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Purpose: Ibrutinib has transformed the management of chronic lymphocytic leukemia (CLL), though its use is limited by toxicity and resistance. In this study, we utilized an “add on” approach for patients who had been treated with ibrutinib in the front-line or relapsed/refractory settings with detectable MRD. Umbralisib and ublituximab (U2) were added on to ibrutinib, patients were treated until achieving undetectable-MRD (U-MRD), and then they entered a period of treatment-free observation (TFO). Patients and Methods: Patients were eligible if they received ibrutinib in any line of therapy for at least 6 months and had detectable MRD (flow cytometry, Results: Twenty-eight patients were enrolled of whom 27 were evaluable for efficacy. Patients received ibrutinib for a median of 21 months (range 7–67) prior to study enrollment. Fourteen patients (52%) have achieved U-MRD per protocol whereas 78% had at least one U-MRD evaluation. Seventeen patients (63%) have entered TFO after a median of 6.4 months on triplet therapy. Progression-free survival at 12 months was estimated at 95%. Grade ≥3 adverse events were hypertension 7%, diarrhea 4%, and increased ALT/AST 4%. Conclusions: This triplet approach utilizes the addition of U2 to ibrutinib as an MRD-driven time-limited therapy. This therapy was well tolerated and effective. TFO following this therapy appears durable in ongoing follow-up.

Supplementary Data from Adding Umbralisib and Ublituximab (U2) to Ibrutinib in Patients with CLL: A Phase II Study of an MRD-Driven Approach

Supplementary Data from Dual Inhibition of Akt/Mammalian Target of Rapamycin Pathway by Nanoparticle Albumin-Bound–Rapamycin and Perifosine Induces Antitumor Activity in Multiple Myeloma

Purpose:Ibrutinib has transformed the management of chronic lymphocytic leukemia (CLL), though its use is limited by toxicity and resistance. In this study, we utilized an “add on” approach for patients who had been treated with ibrutinib in the front-line or relapsed/refractory settings with detectable MRD. Umbralisib and ublituximab (U2) were added on to ibrutinib, patients were treated until achieving undetectable-MRD (U-MRD), and then they entered a period of treatment-free observation (TFO).Patients and Methods:Patients were eligible if they received ibrutinib in any line of therapy for at least 6 months and had detectable MRD (flow cytometry, –4 cutoff for U-MRD). U2 was added to ibrutinib, and patients were monitored serially for MRD. Once U-MRD was achieved or a total of 24 cycles were administered, patients entered a period of TFO. The primary study objective was rate of U-MRD. Secondary endpoints included safety and durability of clinical benefit after treatment discontinuation.Results:Twenty-eight patients were enrolled of whom 27 were evaluable for efficacy. Patients received ibrutinib for a median of 21 months (range 7–67) prior to study enrollment. Fourteen patients (52%) have achieved U-MRD per protocol whereas 78% had at least one U-MRD evaluation. Seventeen patients (63%) have entered TFO after a median of 6.4 months on triplet therapy. Progression-free survival at 12 months was estimated at 95%. Grade ≥3 adverse events were hypertension 7%, diarrhea 4%, and increased ALT/AST 4%.Conclusions:This triplet approach utilizes the addition of U2 to ibrutinib as an MRD-driven time-limited therapy. This therapy was well tolerated and effective. TFO following this therapy appears durable in ongoing follow-up.

The phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway mediates multiple myeloma (MM) cell proliferation, survival, and development of drug resistance, underscoring the role of mTOR inhibitors, such as rapamycin, with potential anti-MM activity. However, recent data show a positive feedback loop from mTOR/S6K1 to Akt, whereby Akt activation confers resistance to mTOR inhibitors. We confirmed that suppression of mTOR signaling in MM cells by rapamycin was associated with upregulation of Akt phosphorylation. We hypothesized that inhibiting this positive feedback by a potent Akt inhibitor perifosine would augment rapamycin-induced cytotoxicity in MM cells. Perifosine inhibited rapamycin-induced phosphorylated Akt, resulting in enhanced cytotoxicity in MM.1S cells even in the presence of interleukin-6, insulin-like growth factor-I, or bone marrow stromal cells. Moreover, rapamycin-induced autophagy in MM.1S MM cells, as evidenced by electron microscopy and immunocytochemistry, was augmented by perifosine. Combination therapy increased apoptosis detected by Annexin V/propidium iodide analysis and caspase/poly(ADP-ribose) polymerase cleavage. Importantly, in vivo antitumor activity and prolongation of survival in a MM mouse xenograft model after treatment was enhanced with combination of nanoparticle albumin-bound–rapamycin and perifosine. Utilizing the in silico predictive analysis, we confirmed our experimental findings of this drug combination on PI3K, Akt, mTOR kinases, and the caspases. Our data suggest that mutual suppression of the PI3K/Akt/mTOR pathway by rapamycin and perifosine combination induces synergistic MM cell cytotoxicity, providing the rationale for clinical trials in patients with relapsed/refractory MM. Mol Cancer Ther; 9(4); 963–75. ©2010 AACR.

Purpose Intolerance is the most common reason for kinase inhibitor (KI) discontinuation in CLL. Umbralisib a novel, highly selective PI3Kδ/CK1e inhibitor, is active and well tolerated in CLL patients. This phase 2 trial evaluated umbralisib in CLL patients who are intolerant to prior BTK or PI3K inhibitor therapy. Patients and methods In this phase 2 trial (NCT02742090), umbralisib was initiated at 800 mg oral daily in CLL patients requiring therapy per investigator discretion who were intolerant to prior BTK or PI3K inhibitor therapy, until progression or toxicity. Primary endpoint was progression-free survival (PFS). Secondary endpoints included time to treatment failure and umbralisib safety profile. DNA isolated from buccal swabs was genotyped for polymorphisms in CYP3A4, CYP3A5 and CYP2D6. Results Fifty-one patients were enrolled (44 BTKi and 7 PI3Kδi intolerant). Median age was 70 years (range 48-96), median of 2 prior lines of therapy (1-7), 24% had del17p and/or TP53 mutation, and 65% were IGHV unmutated. Most common AEs leading to prior KI discontinuation were rash (27%), arthralgia (18%), and atrial fibrillation (16%). Median progression free survival (PFS) was 23.5 months (95% CI 13.1-not estimable). 58% of patients were on umbralisib for a longer duration than prior KI. Most common (≥5%) grade ≥3 AEs on umbralisib (all causality) were neutropenia (18%), leukocytosis (14%), thrombocytopenia (12%), pneumonia (12%), and diarrhea (8%). Six patients (12%) discontinued umbralisib due to an AE. Eight patients (16%) had dose reductions and were successfully re-challenged. Conclusions Umbralisib is safe and effective in this BTK and alternate PI3K inhibitor intolerant CLL population. These are the first prospective data to confirm that switching from a BTK or alternate PI3K inhibitor to umbralisib can result in durable, well tolerated responses.

Summary Background Patients with chronic lymphocytic leukaemia and high-risk features have poorer outcomes on ibrutinib than those without high-risk features. The aim of this study was to assess the benefit of adding ublituximab, an anti-CD20 monoclonal antibody, to ibrutinib therapy in this population. Methods We did a randomised, phase 3, multicentre study (GENUINE) of patients aged 18 years or older with relapsed or refractory chronic lymphocytic leukaemia with at least one of 17p deletion, 11q deletion, or TP53 mutation, at 119 clinics in the USA and Israel. Eligible patients had received at least one previous chronic lymphocytic leukaemia therapy and had an Eastern Cooperative Oncology Group performance status of 2 or lower. We randomised patients (1:1) using permuted block randomisation with a block size of four and stratified by previous lines of therapy (one vs two or more) to receive ibrutinib alone or ibrutinib in combination with ublituximab. Treatment allocation was not masked to patients or investigators. Ibrutinib was given orally daily at 420 mg for all cycles. Ublituximab was given intravenously in 28-day cycles, with increasing doses during cycle 1 (≤150 mg on day 1, 750 mg on day 2, and 900 mg on days 8 and 15) and continuing at 900 mg on day 1 of cycles 2–6. After cycle 6, ublituximab was given at 900 mg every three cycles. The study was initially designed with co-primary endpoints of progression-free survival and overall response rate but due to protracted patient accrual, the protocol was amended to have a single primary endpoint of independent review committee-assessed overall response rate (defined as the proportion of patients who had a partial response, complete response, or complete response with incomplete marrow recovery according to the 2008 International Workshop on CLL criteria) in the intention-to-treat population. Safety was evaluated in the population of patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov , NCT02301156 , and the final analysis is presented. Findings 224 patients were assessed for eligibility, of whom 126 patients were enrolled and randomly assigned to receive ublituximab plus ibrutinib (n=64) or ibrutinib alone (n=62) between Feb 6, 2015, and Dec 19, 2016. After a median follow-up of 41·6 months (IQR 36·7–47·3), the overall response rate was 53 (83%) of 64 patients in the ublituximab plus ibrutinib group and 40 (65%) of 62 patients in the ibrutinib group (p=0·020). 117 patients, including 59 in the ublituximab plus ibrutinib group and 58 in the ibrutinib group, received at least one dose of treatment and were included in safety analyses. Most adverse events were grade 1 or 2. The most common grade 3 and 4 adverse events were neutropenia (11 [19%] patients in the ublituximab plus ibrutinib group and seven [12%] in the ibrutinib group), anaemia (five [8%] and five [9%]), and diarrhoea (six [10%] and three [5%]). The most common serious adverse events were pneumonia (six [10%] in the ublituximab plus ibrutinib group and four [7%] in the ibrutinib group), atrial fibrillation (four [7%] and one [2%]), sepsis (four [7%] and one [2%]), and febrile neutropenia (three [5%] and one [2%]). Two patients in the ublituximab plus ibrutinib group died due to adverse events (one cardiac arrest and one failure to thrive), neither of which were treatment-related. Five patients in the ibrutinib group died due to adverse events, including one cardiac arrest, one cerebral infarction, one intracranial haemorrhage, one Pneumocystis jirovecii pneumonia infection, and one unexplained death; the death due to cardiac arrest was considered to be treatment-related. Interpretation The addition of ublituximab to ibrutinib resulted in a statistically higher overall response rate without affecting the safety profile of ibrutinib monotherapy in patients with relapsed or refractory high-risk chronic lymphocytic leukaemia. These findings provide support for the addition of ublituximab to Bruton tyrosine kinase inhibitors for the treatment of these patients. Funding TG Therapeutics.

Background: Umbralisib is an oral, once-daily, novel, dual inhibitor of phosphatidylinositol-3-kinase-delta (PI3Kδ) and casein kinase-1ε (CK1ε) that exhibits improved selectivity for the delta isoform of PI3K. Ublituximab is a novel anti-CD20 monoclonal antibody glycoengineered for enhanced antibody-dependent cellular cytotoxicity that targets a unique epitope on CD20. U2 has been well-tolerated and demonstrated promising activity in heavily pre-treated CLL patients. Herein, results are presented for the randomized, multicenter, Phase 3 UNITY-CLL trial (NCT02612311), which evaluated U2 vs O+Chl in patients with TN and R/R CLL. Methods: Patients ≥18 years of age with treatment-naïve (TN) or relapsed/refractory (R/R) CLL requiring treatment per iwCLL criteria with adequate organ function and ECOG PS ≤2 were eligible. Stratification factors included treatment status (TN vs R/R) and del(17p) status. Patients were initially randomized 1:1:1:1 to receive U2, O+Chl, umbralisib monotherapy, or ublituximab monotherapy. Following establishment of contribution comparing U2 to the single agents, patients were randomized 1:1 to U2 or O+Chl. Umbralisib was given orally at 800 mg once-daily until progression or removal from treatment for other reasons. Ublituximab was administered intravenously at 900 mg on Days 1/2 [split 150/750 mg], 8, and 15 of Cycle 1, Day 1 of Cycles 2 - 6, and on Day 1 every 3 cycles after Cycle 6. O was given intravenously at 1000 mg on Days 1/2 [split 100/900], 8, and 15 of Cycle 1, and Day 1 of Cycles 2 - 6. Chl was given orally at 0.5 mg/kg on Day 1 and 15 of Cycles 1 - 6. Each cycle was 28 days. The primary endpoint was independent review committee (IRC)-assessed progression-free survival (PFS) of U2 vs O+Chl. Key secondary endpoints included IRC-assessed overall response rate (ORR), complete response (CR), undetectable minimal residual disease (uMRD), duration of response (DOR), and safety (assessed from the first dose until 30 days after the last dose of study medication in each arm) as well as contribution of umbralisib and ublituximab to the U2 combination. Results: From Feb 2016 - Oct 2017, 421 pts were randomized to the U2 (n=210) or O+Chl (n=211) arms. The median age was 67 y (range, 36-91); 57% of patients (n=240) were treatment-naïve; 43% (n=181) had R/R CLL (median number of prior treatments = 1); 10% had del(17p), 20% del(11q), and 56% were IgHV unmutated. 66% were male. Demographics were well-balanced between treatment arms. At a median follow-up of 36.2 mos, U2 significantly prolonged PFS vs O+Chl (median 31.9 mos vs 17.9 mos; HR 0.546, 95% CI 0.413-0.720, P The median treatment duration was 23 mos for U2 (range, 0.1 - 49 mos) and 5 mos (range, 0.1 - 7 mos) for O+Chl. G3/4 AEs of interest regardless of causality (U2 vs O+Chl) included neutropenia (30.6% vs 34.7%), thrombocytopenia (3.4% vs 13.1%), diarrhea (12.1% vs 2.5%), infusion related reaction (1.9% vs 3.5%), elevated AST/ALTs (8.3% vs 2%), colitis (3.4% vs 0%) and pneumonitis (2.9% vs 0%). AEs led to treatment discontinuation in 34 patients (16.5%) on U2 and 16 patients (7.6%) on O+Chl. Conclusions: UNITY-CLL is the first randomized Phase 3 study in CLL of a PI3Ki vs. chemoimmunotherapy, and the first randomized study of a PI3Ki in treatment-naive CLL. U2 exhibited a well-tolerated safety profile, and significantly improved PFS vs. standard of care chemoimmunotherapy in patients with treatment-naive and relapsed/refractory CLL. Figure Disclosures Gribben: Janssen: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Celgene: Research Funding; Abbvie: Honoraria. Jurczak:Celgene: Research Funding; Afimed: Research Funding; Sandoz-Novartis: Consultancy; European Medicines Agency,: Consultancy; AstraZeneca: Consultancy; Takeda: Research Funding; Janssen China R&D: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Bayer: Research Funding; Acerta: Consultancy, Research Funding; Pharmacyclics: Research Funding; Maria Sklodowska-Curie National Research Institute of Oncology, Krakow, Poland: Current Employment; MEI Pharma: Research Funding; Nordic Nanovector: Research Funding; Servier: Research Funding; Merck: Research Funding; Gilead Sciences: Research Funding; Epizyme: Consultancy; Roche: Research Funding; MorphoSys: Research Funding; TG Therapeutics, Inc.: Research Funding; Jagiellonian University, Krakow, Poland: Ended employment in the past 24 months. Jacobs:Sanofi Genzyme: Speakers Bureau; Genentech: Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Verastem: Consultancy; Seattle Genetics: Consultancy; Astra Zeneca: Consultancy, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Pharmacyclics: Research Funding, Speakers Bureau; TG Therapeutics, Inc.: Research Funding. Giannopoulos:BMS-Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Janssen: Honoraria. Wrobel:Janssen-Cilag: Honoraria, Research Funding, Speakers Bureau. Zafar:Bristol Meyers Squibb: Honoraria, Other: TRAVEL, ACCOMODATIONS, EXPENSES (paid by any for-profit health care company); Florida Cancer Specialists and Research Institute: Current Employment; Sarah Canon Research Institute: Research Funding; Karyopharm: Honoraria; AstraZeneca: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Danilov:Nurix: Consultancy; Celgene: Consultancy; Astra Zeneca: Consultancy, Research Funding; Aptose Biosciences: Research Funding; Gilead Sciences: Research Funding; Verastem Oncology: Consultancy, Research Funding; Pharmacyclics: Consultancy; Abbvie: Consultancy; BeiGene: Consultancy; Takeda Oncology: Research Funding; Karyopharm: Consultancy; TG Therapeutics: Consultancy; Genentech: Consultancy, Research Funding; Rigel Pharmaceuticals: Consultancy; Bristol-Myers Squibb: Research Funding; Bayer Oncology: Consultancy, Research Funding. Burke:Gilead: Consultancy; Epizyme: Consultancy; Adaptive: Consultancy; Kura: Consultancy; Astra Zeneca: Consultancy; Bayer: Consultancy; Bristol Myers Squibb: Consultancy; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; Morphosys: Consultancy; Verastem: Consultancy; Roche: Consultancy; Seattle Genetics: Speakers Bureau; Celgene: Consultancy. Goldschmidt:Bristol-Myers Squibb: Speakers Bureau; Amgen: Consultancy; Blue Ridge Cancer Care: Current Employment. Huntington:Genentech: Consultancy; Astrazeneca: Honoraria; TG Therapeutics: Research Funding; Pharmacyclics: Honoraria; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Bayer: Consultancy, Honoraria; AbbVie: Consultancy; DTRM: Research Funding. Pinilla Ibarz:AstraZeneca: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Novartis: Consultancy; Sunesis Pharmaceuticals: Consultancy; TG Therapeutics: Consultancy; Sanofi: Consultancy; Pharmacyclics: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau. Sharman:Bristol Meyers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Acerta: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; BeiGene: Research Funding. Siddiqi:AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding; Juno: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Oncternal: Research Funding; TG Therapeutics: Research Funding; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau. Brander:MEI Pharma: Other, Research Funding; Pfizer: Consultancy, Other; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other, Research Funding; Novartis: Consultancy, Other; Teva: Consultancy, Honoraria; Tolero: Research Funding; ArQule: Consultancy, Other, Research Funding; Ascentage: Other, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Tolero: Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; NCCN: Other; Verastem: Consultancy, Honoraria, Other, Research Funding; Teva: Consultancy, Honoraria; Novartis: Consultancy, Other; AstraZeneca: Consultancy, Honoraria, Other, Research Funding; BeiGene: Other, Research Funding; DTRM: Other, Research Funding; NCCN: Other; Genentech: Consultancy, Honoraria, Other, Research Funding; Juno/Celgene/BMS: Other, Research Funding. Kolibaba:TG Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Research Funding; Sumitomo Dainippon Pharma Oncology: Consultancy, Other; Verastem: Honoraria; Genentech: Research Funding; Gilead: Research Funding; Janssen: Research Funding; McKesson Life Sciences: Consultancy; Novartis: Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; AbbVie: Research Funding; Atara Biotech: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Cell Therapeutics: Research Funding; Compass Oncology: Ended employment in the past 24 months. Ghosh:Karyopharm: Consultancy; Genmab: Consultancy, Speakers Bureau; AbbVie: Speakers Bureau; AstraZeneca: Speakers Bureau; Celgene/Bristol-Myers Squibb: Speakers Bureau; Forty Seven Inc: Consultancy, Other: Research Bureau, Research Funding; Janssen: Consultancy, Research Funding, Speakers Bureau; Juno/Celgene/Bristol-Myers Squibb: Consultancy, Research Funding; Kite/Gilead: Consultancy, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; SGN: Consultancy, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Research Funding; Roche/Genentech: Research Funding. Sportelli:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miskin:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor:Astex Pharmaceuticals: Honoraria, Research Funding; Celgene: Honoraria, Other: Data Safety Monitoring Committee, Research Funding; TG Therapeutics: Current Employment, Current equity holder in publicly-traded company; Kymera Therapeutics: Current equity holder in private company, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nomocan: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Mundipharma: Other: Consulting; Servier: Consultancy. Weiss:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Flinn:Iksuda Therapeutics: Consultancy; Curis: Research Funding; Infinity Pharmaceuticals: Research Funding; F. Hoffmann-La Roche: Research Funding; Vincera Pharma: Consultancy; Karyopharm Therapeutics: Research Funding; Gilead Sciences: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Triphase Research & Development Corp.: Research Funding; Trillium Therapeutics: Research Funding; TG Therapeutics: Consultancy, Research Funding; Teva: Research Funding; Seattle Genetics: Consultancy, Research Funding; ArQule: Research Funding; Unum Therapeutics: Consultancy, Research Funding; Incyte: Research Funding; Forma Therapeutics: Research Funding; Loxo: Research Funding; BeiGene: Consultancy, Research Funding; Kite Pharma: Consultancy, Research Funding; MorphoSys: Consultancy, Research Funding; Forty Seven: Research Funding; Genentech, Inc.: Research Funding; Great Point Partners: Consultancy; IGM Biosciences: Research Funding; Juno Therapeutics: Consultancy, Research Funding; Acerta Pharma: Research Funding; AbbVie: Consultancy, Research Funding; Celgene: Research Funding; Johnson & Johnson: Other; Yingli Pharmaceuticals ≠: Consultancy, Research Funding; Rhizen Pharmaceuticals: Research Funding; Roche: Consultancy, Research Funding; Curio Science: Consultancy; Nurix Therapeutics: Consultancy; Takeda: Consultancy, Research Funding; Calithera Biosciences: Research Funding; Merck: Research Funding; Constellation Pharmaceuticals: Research Funding; Agios: Research Funding; Portola Pharmaceuticals: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Pfizer: Research Funding; Novartis: Research Funding.

PURPOSE Phosphatidylinositol-3-kinase (PI3K) inhibitors have shown activity in relapsed or refractory (R/R) indolent non-Hodgkin lymphoma (iNHL). PI3K inhibitors have been hampered by poor long-term tolerability and toxicity, which interfere with continuous use. Umbralisib, a dual inhibitor of PI3Kδ/casein kinase-1ε, exhibits improved selectivity for PI3Kδ compared with other PI3K inhibitors. This phase IIb trial was designed to evaluate the efficacy and safety of umbralisib in patients with R/R iNHL. PATIENTS AND METHODS In this multicohort, open-label, phase IIb study, 208 patients with R/R marginal zone, follicular, or small lymphocytic lymphoma (MZL, FL, or SLL) unresponsive to prior treatments (≥ 1 MZL; ≥ 2 FL/SLL), including ≥ 1 anti-CD20–based therapy, were administered umbralisib 800 mg orally once daily until disease progression, unacceptable toxicity, or study withdrawal. Primary end point is overall response rate; secondary end points include time to response, duration of response, progression-free survival, and safety. RESULTS The median follow-up is 27.7 months (efficacy) and 21.4 months (safety). The overall response rate was 47.1%, and tumor reduction occurred in 86.4% of patients. The median time to response was 2.7-4.6 months. The median duration of response was not reached for MZL, 11.1 months for FL, and 18.3 months for SLL. Median progression-free survival was not reached for MZL, 10.6 months for FL, and 20.9 months for SLL. At least one grade ≥ 3 treatment-emergent adverse event (TEAE) was reported in 53.4% of patients. TEAEs led to umbralisib discontinuation in 32 patients (15.4%). A total of 31 patients (14.9%) discontinued because of a treatment-related adverse event. Grade ≥ 3 TEAEs reported in ≥ 10% of patients: neutropenia (11.5%) and diarrhea (10.1%). Increased ALT/AST (grade ≥ 3) occurred in 6.7%/7.2% of patients. CONCLUSION Umbralisib achieved meaningful clinical activity in heavily pretreated patients with iNHL. The safety profile was manageable, with a relatively low incidence of immune-mediated toxicities and adverse event–related discontinuations.

Targeting both CD20 and phosphatidylinositol 3-kinase (PI3K), a protein that is critically involved in B-cell maturation, could be an efficacious strategy for treating B-cell malignancies. The safety of the next-generation compounds umbralisib, a PI3K-δ inhibitor, plus ublituximab, an anti-CD20 monoclonal antibody (combination referred to as U2), was evaluated in patients with chronic lymphocytic lymphoma (CLL) or non-Hodgkin lymphoma (NHL) in this phase 1/1b study. Phase 1 dose escalation was performed with a 3 + 3 design to establish the maximum tolerated dose. In this portion, ublituximab was given intravenously (NHL, 900 mg; CLL, 600 or 900 mg) for 12 cycles. Umbralisib was given orally once daily at 800 or 1200 mg (initial formulation) or 400 to 1200 mg (micronized formulation) in the phase 1 dose escalation portion, and at 800 to 1200 mg in the phase 1b portion until progression, toxicity, or study removal. The maximum tolerated dose was not reached in either the CLL or NHL cohort, and only 1 dose-limiting toxicity was observed. U2 had low instances of grade 3 or higher diarrhea (8%), pneumonia (8%), or hepatic toxicity (4%). Treatment discontinuation due to adverse events occurred in 13% of patients, and umbralisib dose reductions occurred in 15% of patients. The overall response rate for all patients was 46% with 17% complete responses. The median duration of response was 20 months (95% confidence interval, 11.3-not reached). U2 was well tolerated, and no new safety signals were observed over single-agent umbralisib. Preliminary efficacy with this combination is promising and warrants further investigation. This study was registered at www.clinicaltrials.gov as #NCT02006485.

Summary Background Therapeutic approaches for B-cell malignancies continue to evolve, especially with regard to combination approaches. We assessed the safety and efficacy of the triplet ublituximab, umbralisib, and ibrutinib in patients with advanced B-cell malignancies. Methods We did an open-label, phase 1 study with dose-escalation and dose-expansion phases, at five centres in the USA. Eligible patients were aged 18 years or older with histologically confirmed lymphocytic leukaemia or relapsed or refractory B-cell non-Hodgkin lymphoma, had measurable disease, adequate organ function, and an Eastern Cooperative Oncology Group (ECOG) performance status of 2 or less. Patients with known CNS lymphoma, active hepatitis B or C infection, or HIV were excluded. In the dose-escalation cohort, patients were treated in cycles of 28 days with escalating doses of oral umbralisib (400, 600, or 800 mg) and fixed doses of intravenous ublituximab (900 mg) and oral ibrutinib (420 mg for patients with chronic lymphocytic leukaemia; 560 mg for patients with B-cell non-Hodgkin lymphoma) in a standard 3 × 3 design until disease progression or intolerance. In the dose-expansion phase, patients were given the recommended dose of the drug combination as determined from the dose-escalation phase. The primary endpoints were safety, dose-limiting toxicities, and the maximum tolerated dose of umbralisib, when given in combination with ublituximab and ibrutinib. Safety was assessed in patients who received at least one dose of study drug; activity was assessed in all patients who had at least one post-treatment efficacy measurement. The study is ongoing but no longer recruiting patients. This trial is registered with ClinicalTrials.gov, number NCT02006485. Findings Between Sept 2, 2014, and Nov 6, 2017, we enrolled 46 patients: 24 in the dose-escalation cohort (n=14 chronic lymphocytic leukaemia or small lymphocytic lymphoma; n=10 B-cell non-Hodgkin lymphoma) and 22 in the dose-expansion cohort (n=9 chronic lymphocytic leukaemia or small lymphocytic lymphoma; n=13 B-cell non-Hodgkin lymphoma). 46 patients received at least one dose of study drug. The maximum tolerated dose of umbralisib was not reached. The recommended dose for the dose-expansion phase was umbralisib 800 mg orally once daily plus ibrutinib orally once daily and intravenous ublituximab 900 mg administered on days 1, 8, and 15 of cycle 1, day 1 of cycles 2–6, and on day 1 of cycles 9 and 12. 37 (84%) of 44 patients achieved an overall response (complete or partial response). The most common any-grade adverse events were diarrhoea (n=27 [59%]), fatigue (n=23 [50%]), infusion-related reaction (n=20 [43%]), dizziness (n=17 [37%]), nausea (n=17 [37%]), and cough (n=16 [35%]). Grade 3–4 adverse events were manageable with the most common being neutropenia (n=10 [22%]) and cellulitis (n=6 [13%]). Serious adverse events occurred in 11 (24%) of 46 patients and included rash (n=2 [4%]), pneumonia (n=2 [4%]), atrial fibrillation (n=2 [4%]), sepsis (n=2 [4%]), abdominal pain (n=1 [2%]), syncope (n=1 [2%]), cellulitis (n=1 [2%]), pneumonitis (n=1 [2%]), headache (n=1 [2%]), lung infection (n=1 [2%]), skin infection (n=1 [2%]), pleural effusion (n=1 [2%]), pericardial infusion (n=1 [2%]), upper gastrointestinal bleeding (n=1 [2%]), diarrhoea (n=1 [2%]), and weakness (n=1 [2%]). No deaths related to adverse events occurred. Interpretation The combination of ublituximab, umbralisib, and ibrutinib seems to be tolerable and is associated with encouraging activity in advanced chronic lymphocytic leukaemia and B-cell non-Hodgkin lymphoma. This triplet combination will require further investigation in future studies to improve understanding of this novel, chemotherapy-free triplet combination in the management of these cancers. Funding TG Therapeutics.

Summary Background Patients with relapsed or refractory high-risk chronic lymphocytic leukaemia or mantle cell lymphoma often do not derive durable benefit from ibrutinib monotherapy. We hypothesised that dual B-cell receptor pathway blockade would be tolerable and efficacious. We investigated a next-generation phosphoinositide-3-kinase-δ inhibitor (PI3K-δi), umbralisib, plus a Bruton tyrosine kinase inhibitor (BTKi), ibrutinib, in relapsed or refractory chronic lymphocytic leukaemia and mantle cell lymphoma. Methods We did an investigator-initiated, multicentre, phase 1–1b study of patients from five sites in the USA (academic and community sites). Patients were 18 years and older with relapsed or refractory chronic lymphocytic leukaemia or mantle cell lymphoma, with an Eastern Cooperative Oncology Group performance status of 2 or less, and were given umbralisib orally once daily (400 mg, 600 mg, or 800 mg) and ibrutinib orally once daily (420 mg for chronic lymphocytic leukaemia or 560 mg for mantle cell lymphoma) until disease progression or unacceptable toxicity. The phase 1 dose-escalation cohorts for each histology escalated independently in a standard 3 × 3 design. The primary endpoints were intention-to-treat assessment of maximum-tolerated dose, safety, and dose-limiting toxicities. This trial is ongoing and is registered with ClinicalTrials.gov , number NCT02268851 . Findings Between Dec 5, 2014, and March 7, 2018, we enrolled 44 patients, of which 42 were given at least one dose of study drug (chronic lymphocytic leukaemia, n=21; mantle cell lymphoma, n=21). Patients had a median age of 68 years (range 48–85) and had a median of two (IQR 1–3) previous therapies. No dose-limiting toxicities were observed and the maximum-tolerated dose of umbralisib was not reached. The recommended phase 2 dose of umbralisib when given in combination with ibrutinib was 800 mg once daily. The most frequent adverse events included diarrhoea (22 [52%] patients, 10% of whom had grade 3), infection (21 [50%], 17% grade 3–4), and transaminitis (ten [24%], 2% grade 3). Serious adverse events occurred in 12 (29%) patients and included lipase elevation, atrial fibrillation, hypophosphataemia, adrenal insufficiency, transaminitis, and infections. Interpretation Umbralisib plus ibrutinib is well tolerated and active in relapsed or refractory chronic lymphocytic leukaemia and mantle cell lymphoma, with a recommended phase 2 dose of umbralisib 800 mg once daily. To the best of our knowledge, these are the first clinical data on a BTKi and PI3K-δi doublet in B-cell malignancies, and the results suggest that this approach is feasible and worthy of further study. Funding TG Therapeutics, Leukemia and Lymphoma Society Therapy Accelerator Program.

Phosphoinositide 3-kinase-δ (PI3Kδ) inhibitors are active in lymphoid malignancies, although associated toxicities can limit their use. Umbralisib is a dual inhibitor of PI3Kδ and casein kinase-1ε (CK1ε). This study analyzed integrated comprehensive toxicity data from 4 open-label, phase 1 and 2 studies that included 371 adult patients (median age, 67 years) with relapsed/refractory non-Hodgkin lymphoma (follicular lymphoma [n = 147]; marginal zone lymphoma [n = 82]; diffuse large B-cell lymphoma/mantle cell lymphoma [n = 74]; chronic lymphocytic leukemia [n = 43]; and other tumor types [n = 25]) who were treated with the recommended phase 2 dose of umbralisib 800 mg or higher once daily. At data cutoff, median duration of umbralisib treatment was 5.9 months (range, 0.1-75.1 months), and 107 patients (28.8%) received umbralisib for ≥12 months. Any-grade treatment-emergent adverse events (AEs) occurred in 366 (98.7%) of 371 patients, with the most frequent being diarrhea (52.3%), nausea (41.5%), and fatigue (31.8%). Grade 3 or higher treatment-emergent AEs occurred in 189 (50.9%) of 371 patients and included neutropenia (11.3%), diarrhea (7.3%), and increased aminotransferase levels (5.7%). Treatment-emergent serious AEs occurred in 95 (25.6%) of 371 patients. AEs of special interest were limited and included pneumonia (29 of 371 [7.8%]), noninfectious colitis (9 of 371 [2.4%]), and pneumonitis (4 of 371 [1.1%]). AEs led to discontinuation of umbralisib in 51 patients (13.7%). Four patients (1.1%) died of AEs, none of which was deemed related to umbralisib. No cumulative toxicities were reported. The favorable long-term tolerability profile and low rates of immune-mediated toxicities support the potential use of umbralisib for the benefit of a broad population of patients with lymphoid malignancies.

Perifosine, an investigational, oral, synthetic alkylphospholipid, inhibits signal transduction pathways of relevance in multiple myeloma (MM) including PI3K/Akt. Perifosine demonstrated anti-MM activity in preclinical studies and encouraging early-phase clinical activity in combination with bortezomib. A randomized, double-blind, placebo-controlled phase 3 study was conducted to evaluate addition of perifosine to bortezomib-dexamethasone in MM patients with one to four prior therapies who had relapsed following previous bortezomib-based therapy. The primary endpoint was progression-free survival (PFS). The study was discontinued at planned interim analysis, with 135 patients enrolled. Median PFS was 22.7 weeks (95% confidence interval 16·0-45·4) in the perifosine arm and 39.0 weeks (18.3-50.1) in the placebo arm (hazard ratio 1.269 [0.817-1.969]

Background: The median age at diagnosis of patients with Chronic Lymphocytic Leukemia (CLL) is 70 years, which presents unique challenges for disease management, as these patients have more comorbidities and often require multiple concomitant medications. While some baseline characteristics (e.g., history of cardiovascular or bleeding issues) may create potential risk for significant medical events, others (e.g., hypertension, joint pain) threaten the ability of patients to stay on long-term continuous BTKi, compromising optimal therapeutic benefit. The tolerability of Bruton's tyrosine kinase inhibitors (BTKi) can be suboptimal in these patients, emphasizing the need for novel non-chemotherapy regimens with a differentiated risk profile. The combination of umbralisib and ublituximab (U2) demonstrated superior progression-free survival (PFS) and overall response rates (ORR) compared to chemoimmunotherapy in the primary analysis of the randomized, multicenter, Phase 3 UNITY-CLL trial (NCT02612311) (Gribben et al. 2020). Herein, an analysis was conducted of patients treated with U2 on UNITY-CLL who had a pre-existing comorbidity or concomitant medication that could potentially preclude the use of BTKi. Methods: Patients ≥18 years of age with CLL who were treatment-naïve (TN) or previously treated (PT) requiring treatment per iwCLL criteria with adequate organ function and ECOG PS ≤2 were eligible. Patients were initially randomized 1:1:1:1 to receive U2, obinutuzumab+chlorambucil (O+Chl), umbralisib monotherapy, or ublituximab monotherapy. Stratification factors included treatment status (TN vs. PT) and deletion 17p (del17p) status. Umbralisib was given orally at 800 mg once daily until progression or removal from treatment for other reasons. Ublituximab was administered intravenously at 900 mg on Days 1/2 [split 150/750 mg], 8, and 15 of Cycle 1, Day 1 of Cycles 2-6, and on Day 1 every 3 cycles after Cycle 6. The primary endpoint was independent review committee (IRC)-assessed PFS of U2 compared to O+Chl. Key secondary endpoints included IRC-assessed ORR, complete response, undetectable minimal residual disease (uMRD), duration of response, and safety, assessed from the first dose until 30 days after the last dose of study medication. BTKi risk factors were defined by the comorbidities and concomitant medication categories listed in Table 1 and include pre-existing arrythmias, cardiovascular dysfunction, history of major bleeding, hypertension, and joint pain. Results: In the UNITY-CLL study, 206 subjects with CLL received treatment with U2. Among these patients, the median age was 67 years, 9% had del17p, 54% had unmutated IGHV, and 57% were TN. Among these patients, 131 (63.6%) met at least 1 BTKi risk factor criteria (Table 1). Among patients with BTKi risk factors, the median age was slightly higher at 69 years, 11% had del17p, 56% were unmutated IGHV, and 57% were TN. At a median follow-up of 36.7 months, 40% remain on U2 as compared to 37% for the entire U2 population. The median PFS for patients with a BTKi risk factor was equivalent to the entire U2 population at 31.9 months, and a similar ORR (88% vs 83%, difference not statistically significant) was observed in this population as compared to the overall U2 population. In terms of safety, there were no differences in the incidences of SAEs, grade ≥3 AEs, fatal AEs, or discontinuations due to AEs. Conclusions: Patients with BTKi risk factors attained durable clinical benefit from U2. In this population with BTKi risk factors, the baseline disease characteristics aligned with the overall population treated with U2, and efficacy and safety outcomes did not appear to be negatively impacted by the presence of comorbidities or the use of concomitant medications. These data suggest that U2 can be a valuable treatment option for patients with these conditions. Figure 1 Figure 1. Disclosures Pinilla Ibarz: AbbVie, Janssen, AstraZeneca, Novartis, TG Therapeutics, Takeda: Consultancy, Other: Advisory; Sellas: Other: ), patents/royalties/other intellectual property; AbbVie, Janssen, AstraZeneca, Takeda: Speakers Bureau; MEI, Sunesis: Research Funding. Jurczak: Abbvie: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celtrion: Research Funding; Celgene: Research Funding; Debbiopharm: Research Funding; Epizyme: Research Funding; Incyte: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Mei Pharma: Research Funding; Morphosys: Research Funding; Novo Nordisk: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sandoz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; TG Therapeutics: Research Funding. Lech Maranda: Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board, lectures; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board, lectures; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board, lectures; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Sanofi: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board, lectures; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board, lectures; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board, lectures. Wróbel: BeiGene: Honoraria; Takeda: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; BMS: Honoraria; Roche: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria, Speakers Bureau. Sharman: AstraZeneca: Consultancy; TG Therapeutics: Consultancy; Centessa: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics LLC, an AbbVie Company: Consultancy; Lilly: Consultancy; BMS: Consultancy; BeiGene: Consultancy; AbbVie: Consultancy. Hoffmann: TG Therapeutics: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pharmcyclics: Consultancy, Honoraria; celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Huntington: Flatiron Health Inc.: Consultancy; DTRM Biopharm: Research Funding; TG Therapeutics: Research Funding; AstraZeneca: Consultancy, Honoraria; Novartis: Consultancy; AbbVie: Consultancy; SeaGen: Consultancy; Genentech: Consultancy; Servier: Consultancy; Bayer: Honoraria; Thyme Inc: Consultancy; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Research Funding. Jacobs: Adaptive Biotechnologies: Consultancy; ADC Therapeutics: Consultancy; SecuraBio: Consultancy, Speakers Bureau; Genentech: Consultancy; Jannsen: Speakers Bureau; TG Therapeutics: Research Funding, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; Verastem: Consultancy; AbbVie: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; TeneoBio: Research Funding; MEI Pharma: Research Funding. Rowland: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Sportelli: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Weiss: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor: Myeloid Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Dren: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Kymera: Consultancy, Current equity holder in publicly-traded company; TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Nomocan: Consultancy; Mundipharma: Consultancy. Flinn: Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding.

Background: While time-limited novel agent combinations have demonstrated high overall response rates and durable responses for patients with chronic lymphocytic leukemia (CLL), they also have high rates of adverse events and possibly overtreat many favorable risk patients. Meanwhile, patients receiving indefinite ibrutinib monotherapy are at risk for cumulative toxicity and acquired resistance with continuous exposure. To address these challenges, we utilized an "add-on" approach to combination therapy after a period of ibrutinib monotherapy exposure. We examined the addition of umbralisib (a selective PI3Kδ and casein kinase-1epsilon [CK1ε] inhibitor) and ublituximab (a novel anti-CD20 monoclonal antibody glycoengineered for enhanced antibody-dependent cellular cytotoxicity; U2) to ibrutinib in CLL patients with detectable minimal residual disease (MRD) after an initial period of treatment with ibrutinib monotherapy. With this strategy, we aimed to induce undetectable MRD (uMRD), minimize the risk of developing BTKi resistance mutations, stop all CLL-directed therapy, and achieve a durable treatment-free observation (TFO) period in CLL patients who would most benefit from combination therapy. Methods: This is a phase II, multicenter, open label clinical trial (NCT04016805). Eligible patients were receiving ongoing ibrutinib, in any line of therapy, for a minimum duration of 6 months and had detectable residual CLL in the peripheral blood via MRD assay (flow cytometry with a cutoff of 10^-4 for uMRD). Umbralisib (administered daily at 800mg) and ublituximab (administered intravenously at 900 mg on Days 1/2 [split 150/750 mg], 8, and 15 of Cycle 1, Day 1 of Cycles 2-6, and on Day 1 every 3 cycles after Cycle 6) were added to ibrutinib, and patients were monitored serially for MRD starting on Cycle 3 Day 1. Once uMRD was achieved and confirmed 4 weeks later, patients entered a period of TFO. Patients who did not attain uMRD continued treatment for up to 24 cycles followed by TFO. The primary objective of the study was rate of uMRD, with a prespecified MRD conversion rate of 25% defined as promising. Secondary endpoints included safety and durability of clinical benefit after treatment discontinuation. Results: In this fully accrued study, U2 was added to ibrutinib in 26 patients. Median age was 63 years (range, 48-81) and 77% were male. Disease characteristics included del(17p) in 8%, del(11q) in 12%, and unmutated IGHV in 31%. Median duration of ibrutinib treatment prior to addition of U2 was 22 months (range 7-66 months). The swimmer plot in Figure 1 depicts time on ibrutinib prior to enrolling in this study, the duration of treatment with triplet therapy, achievement of uMRD, and TFO. MRD has been assessed in 24 patients; 71% (17/24) had uMRD in at least 1 assessment. Median time to first uMRD result was 5 months (range 2 - 12). A total of 16 patients (67%) entered TFO; 15 had 2 consecutive uMRD assessments and 1 completed 24 cycles with detectable MRD. TFO appears durable, with a median of 242 days off therapy (range 5-538 days) as of the data cutoff. 73% remain uMRD at last follow up. No patient has progressed or required re-treatment per iwCLL criteria. U2 plus ibrutinib was well tolerated. All-causality grade 3/4 adverse events of special interest included ALT/AST increase (4%), diarrhea (4%), and hypertension (8%). Two patients discontinued all therapy due to rash; both were uMRD at the time of treatment discontinuation and remain uMRD. One patient died due to complications of COVID-19. Conclusions: This is the first MRD-driven approach utilizing the combination of BTKi, PI3Ki, and anti-CD20 monoclonal antibody. This novel agent combination therapy was well tolerated and effective, with achievement of uMRD in 71% of evaluable patients. This "add-on" approach for patients on continuous ibrutinib resulted in deep remissions that allowed for a tailored, time-limited therapy and sustained treatment-free observation. Figure 1 Figure 1. Disclosures Roeker: Pharmacyclics: Consultancy; TG Therapeutics: Consultancy; Pfizer: Consultancy, Research Funding; AbbVie, AstraZeneca, Janssen, LOXO, Pharmacyclics, TG Therapeutics, Vaniam Group, Verastem: Consultancy; Abbot Laboratories: Current equity holder in publicly-traded company; Loxo Oncology: Consultancy. Leslie: Karyopharm Therapeutics: Honoraria, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; Epizyme: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria; Merck: Consultancy; Janssen: Consultancy, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy; BeiGene: Consultancy, Honoraria, Speakers Bureau; Seagen: Consultancy, Honoraria, Speakers Bureau; Celgene/BMS: Consultancy, Honoraria, Speakers Bureau; PCYC/Janssen: Consultancy, Honoraria, Speakers Bureau; Pharmacyclics: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau. Soumerai: Abbvie: Consultancy; Adaptive Biotechnologies: Consultancy; AstraZeneca: Consultancy; BeiGene: Consultancy, Research Funding; BMS: Consultancy; BostonGene: Research Funding; GlaxoSmithKline: Research Funding; Seattle Genetics: Consultancy; TG Therapeutics: Consultancy, Research Funding. Zelenetz: MorphoSys: Honoraria; AstraZeneca: Honoraria; Gilead: Honoraria, Research Funding; Verastem: Honoraria; BMS/Celgene/JUNO: Honoraria, Other; NCCN: Other; Gilead: Honoraria; LFR: Other; MEI Pharma: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Janssen: Honoraria; Beigene: Honoraria, Other, Research Funding; SecuraBio: Honoraria; Amgen: Honoraria; Pharmacyclics: Honoraria; MethylGene: Research Funding; Genentech/Roche: Honoraria, Research Funding; Novartis: Honoraria. Falchi: Abbvie: Consultancy, Research Funding; Roche: Research Funding; Genetech: Research Funding; Genmab: Consultancy, Research Funding. Park: Curocel: Consultancy; PrecisionBio: Consultancy; BMS: Consultancy; Minerva: Consultancy; Novartis: Consultancy; Affyimmune: Consultancy; Innate Pharma: Consultancy; Kite Pharma: Consultancy; Autolus: Consultancy; Kura Oncology: Consultancy; Servier: Consultancy; Amgen: Consultancy; Artiva: Consultancy; Intellia: Consultancy. Battiato: Janssen Pharmaceutical: Other: Advisory Board July 2020; Abbvie Pharmaceuticals: Other: CLL Steering Committee November 2020-present. Thompson: VJHemOnc: Honoraria; Curio Science: Honoraria; MJH Life Sciences: Honoraria. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Sportelli: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Mato: Janssen: Consultancy, Research Funding; LOXO: Consultancy, Research Funding; MSKCC: Current Employment; Adaptive Biotechnologies: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; TG Therapeutics: Consultancy, Other: DSMB, Research Funding; Nurix: Research Funding; AstraZeneca: Consultancy; Acerta/AstraZeneca: Consultancy, Research Funding; Sunesis: Consultancy, Research Funding; Genmab: Research Funding; AbbVie: Consultancy, Research Funding; DTRM BioPharma: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Johnson and Johnson: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding.

Background: Patients with relapsed or refractory (R/R) DLBCL generally have a poor prognosis, particularly if they are not candidates for autologous stem cell transplantation (ASCT) or experience relapse following approved CAR-T therapies. The UNITY-NHL study systematically explored the efficacy and tolerability of the PI3K-d/CK1-e inhibitor, umbralisib, alone (umbra), and in combination with the glycoengineered anti-CD20 monoclonal antibody ublituximab (U2), followed by a cohort treated with U2 plus bendamustine (U2+benda). Herein we report on the experience in a large cohort of patients with R/R DLBCL. Methods: This study explored a sequential combination design as described above. Eligible patients had histologically confirmed R/R DLBCL and were ineligible for ASCT, with no limit on number or type of prior treatment. Umbra was given orally at 800 mg once daily in 28-day cycles (C) until disease progression or unacceptable tolerability. Ublituximab was administered intravenously (IV) on Days 1, 8, and 15 of C1, on Day 1 of C2-6, and on Day 1 every 3C through C24. Benda was administered IV (90 mg/m 2) on Days 1/2 of C1-6. Cell of origin, NGS, and c-myc (FISH) were analyzed centrally. The primary endpoint of the study was overall response rate (ORR) as assessed by an independent review committee. Secondary endpoints included duration of response, progression-free survival, time to response, and safety. Results: 226 patients with DLBCL were enrolled as follows: umbra monotherapy (n=30), U2 (n=66), and U2+benda (n=130). The population demographics included the following features: median age was 72 years (range 32-95); 59% were male; 64% of patients had stage III or IV disease; 58% were refractory to their immediate prior therapy; and the median number of prior therapies was 2 (range 1-8). There were no substantive differences in these characteristics across cohorts. Median follow-up for the umbra, U2, and U2+benda arms was 51 months (range 47-61), 46 months (range 41-57), and 40 months (range 35-47), respectively. Overall and complete response rates for the umbra mono, U2, and U2+benda arms were 13.3% (CR 3.3%), 31.8% (CR 10.6%), and 43.1% (CR 16.9%), respectively. Results pertaining to secondary endpoints are listed in Table 1. Correlation of response to cell of origin and mutation/c-myc status is ongoing and will be available at the time of presentation. Adverse events (AEs) were similar across the cohorts, with the exception of hematologic AEs which were increased in patients receiving benda. The most common all-grade AEs by treatment arm (umbra, U2, and U2+benda, respectively) were diarrhea (47%; 41%; and 48%), nausea (40%; 45%; and 45%), fatigue (33%; 30%; and 41%) and neutropenia (3.3%; 18%; and 32%). All-grade AEs of special interest included non-infectious colitis (3.3%, 1.5%, and 2.3%) and pneumonitis (3%, 1.5%, and 1.5%) in umbra, U2 and U2+benda treated patients respectively. Grade 3/4 AEs were uncommon, with the only events >10% being limited to neutropenia (11% for U2; 27% for U2+benda), and anemia (17% for U2+benda). Conclusions: In the DLBCL cohort of UNITY-NHL, the U2+benda triplet regimen was active and well tolerated in patients with R/R DLBCL who were unsuitable for transplant or who had relapsed following ASCT. Umbra monotherapy and U2 were also well tolerated but resulted in lower ORR than in the U2+benda cohort. Figure 1 Figure 1. Disclosures Burke: X4 Pharmaceuticals: Consultancy; Bristol Myers Squibb: Consultancy; SeaGen: Consultancy, Speakers Bureau; Beigene: Consultancy, Speakers Bureau; Roche/Genentech: Consultancy; Epizyme: Consultancy; Adaptive Biotechnologies: Consultancy; Kura: Consultancy; MorphoSys: Consultancy; AstraZeneca: Consultancy; Kymera: Consultancy; AbbVie: Consultancy; Verastem: Consultancy. Fonseca: Amgen: Honoraria, Speakers Bureau; Celgene/BMS: Honoraria, Speakers Bureau; Dava Oncology: Honoraria; Epizyme: Honoraria; Karyopharm: Honoraria; Sanofi: Honoraria; Abbvie: Honoraria. Jurczak: Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Research Funding; Morphosys: Research Funding; Mei Pharma: Research Funding; Merck: Research Funding; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Epizyme: Research Funding; Debbiopharm: Research Funding; Celgene: Research Funding; Celtrion: Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding; Sandoz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; TG Therapeutics: Research Funding. Melear: TG Therapeutics: Speakers Bureau; Astrazeneca: Speakers Bureau; Janssen: Speakers Bureau. Islas-Ohlmayer: Seagen Inc.: Research Funding. Reeves: Apollomics, Inc.: Research Funding; Tarveda Therapeutics: Research Funding; Ascentage Pharmaceuticals: Research Funding; Clovis Oncology: Research Funding; Arvinas: Research Funding; Pfizer: Research Funding; Ellipses: Research Funding; ImmunoGen: Research Funding; Karyopharm Therapeutics: Honoraria, Research Funding; Moderna: Research Funding; Thrive: Research Funding; Genentech: Research Funding; Incyte Corporation: Research Funding; Astellas Pharma: Research Funding; IDEAYA Biosciences: Research Funding; Pharmacyclics: Research Funding; Loxo Oncology: Research Funding; AbbVie Inc.: Research Funding; Celgene: Research Funding; GSK: Research Funding; Jiangsu Hengrui Medicine Co.: Research Funding; Arcus Biosciences: Research Funding; Calithera: Research Funding; Amgen: Research Funding; Mirati Therapeutics, Inc.: Research Funding; Array BioPharma Inc.: Research Funding; Taiho Pharmaceutical: Research Funding; Boehringer Ingelheim: Research Funding; GI Therapeutics Inc.: Research Funding; Hutchison: Research Funding; MacroGenics: Research Funding; Ipsen: Research Funding; MedImmune, LLC.: Research Funding; BeiGene: Research Funding; TG Therapeutics: Research Funding; Acerta Pharma: Research Funding; Verastem: Research Funding; Janssen Pharmaceuticals: Research Funding, Speakers Bureau; Eisai Co.: Research Funding, Speakers Bureau; Roche Pharma: Research Funding; Novartis Pharmaceuticals: Research Funding; Daiichi Sankyo: Research Funding; Arvinas: Research Funding; CytomX: Research Funding; Sermonix Pharmaceutical: Research Funding; Seattle Genetics: Research Funding; AstraZeneca: Research Funding; Evelo Biosciences: Research Funding. Wróbel: Takeda: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; BMS: Honoraria; Roche: Honoraria, Research Funding, Speakers Bureau; BeiGene: Honoraria; Janssen: Honoraria, Speakers Bureau. Pagel: Incyte/MorphoSys: Consultancy; MEI Pharma: Consultancy; Pharmacyclics/AbbVie: Consultancy; AstraZeneca: Consultancy; Gilead: Consultancy; Actinium Pharmaceuticals: Consultancy; Kite, a Gilead Company: Consultancy; Epizyme: Consultancy; BeiGene: Consultancy. Goldschmidt: Ontada: Current Employment; Blue Ridge Cancer Care: Current Employment; Amgen: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; TG Therapeutics: Honoraria; G1 Therapeutics: Honoraria, Speakers Bureau. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Sportelli: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Nomocan: Consultancy; Dren: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Myeloid Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Kymera: Consultancy, Current equity holder in publicly-traded company; Mundipharma: Consultancy. Ghosh: Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Genmab: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Consultancy, Honoraria; Genentech: Research Funding; Karyopharma: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Adaptive Biotech: Consultancy, Honoraria; Epizyme: Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Honoraria, Speakers Bureau.

Background: Umbralisib, a selective PI3Kδ and casein kinase-1epsilon (CK1ε) inhibitor, is pharmacologically distinct from other PI3K inhibitors and is administered orally once daily. Ublituximab is a novel anti-CD20 monoclonal antibody glycoengineered for enhanced antibody dependent cellular cytotoxicity (ADCC) that targets a unique epitope on CD20. The UNITY-NHL trial (NCT02793583) is a multicenter, open-label, registration-directed Phase 2 study designed to evaluate the safety and efficacy of the umbralisib + ublituximab (umbra+ubli, U2) combination in patients with previously treated NHL . Umbra has been recently approved for the treatment (tx) of previously treated marginal zone lymphoma (MZL) based on reported data (Fowler JCO 2021), and the U2 combination has been shown to be active with a manageable safety profile in patients with relapsed/refractory (R/R) NHL (Lunning Blood 2019). In contrast with other PI3Kis, there has been a low incidence of immune-mediated toxicities with umbra, possibly attributable to enhanced selectivity for the PI3Kδ isoform as well as inhibition of CK1ε. Herein, we present results from the MZL cohort treated with U2. Methods: Eligible patients had histologically confirmed MZL (splenic, nodal, extranodal) and were R/R to ≥1 prior lines of tx which must have included an anti-CD20. Patients were treated with U2: umbra was given orally at 800 mg once daily until progression or unacceptable tolerability and ubli was administered intravenously on Days 1, 8, and 15 of Cycle 1, on Day 1 of Cycles 2-6, and on Day 1 every 3 cycles until Cycle 24 in 28-day tx cycles. The primary endpoint of the study was overall response rate (ORR) as assessed by an independent review committee according to the revised IWG criteria (Cheson 2007). Secondary endpoints included duration of response (DoR), progression-free survival (PFS), time to response (TTR), and safety. Results: 72 MZL patients were enrolled and received U2. The median age was 70 years (range 40-89), 53% were female, 74% had stage III or IV disease, and 25% were refractory to their immediate prior therapy. Patients had received a median of 2 prior regimens (range 1-9). As of the cutoff date, 41 patients remain on tx. The ORR was 68%, with 19% achieving complete response (CR). At a median follow-up of 16 months, median DoR was not reached (12 - not estimable). 90% of patients had a reduction in disease burden from baseline while on U2. Figure 1a depicts efficacy data for U2, and Figure 1b shows the best % change in target lesions from baseline for MZL patients treated with at least 1 dose of U2. The most common adverse events (AEs) were diarrhea (all grades: 49%, grade ≥3: 13%), nausea (all grades: 30%, grade ≥3: 0%), and fatigue (all grades: 36%, grade ≥3: 6%). Other AEs of interest included non-infectious colitis (all grades: 2.8 %, grade ≥3: 2.8%) and rash (all grades: 11%, grade ≥3: 0%). Four patients (5.6%) discontinued due to an AE. Conclusions: U2 was highly active in patients with R/R MZL, with improved efficacy when compared to a prior cohort of MZL patients treated in this study with umbra mono (Fowler JCO 2021). The safety profile of the U2 combination was manageable, with a relatively low incidence of immune-mediated toxicities and AE-related discontinuations. Figure 1 Figure 1. Disclosures Chavez: Bristol Myers Squibb: Speakers Bureau; AstraZeneca: Research Funding; BeiGene: Speakers Bureau; Epizyme: Speakers Bureau; MorphoSys: Speakers Bureau; Karyopharm Therapeutics: Consultancy; Merck: Research Funding; Adaptive: Research Funding; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy; Abbvie: Consultancy; Kite/Gilead: Consultancy. Goldschmidt: AbbVie: Consultancy, Research Funding. Samaniego: Imbrium: Membership on an entity's Board of Directors or advisory committees; Arog: Research Funding. Wrobel: Janssen: Honoraria, Speakers Bureau; Roche: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; BeiGene: Honoraria, Speakers Bureau. Cavallo: ROCHE: Membership on an entity's Board of Directors or advisory committees; Gilead: Speakers Bureau; Servier: Speakers Bureau. Fonseca: Sanofi: Honoraria; Karyopharm: Honoraria; Epizyme: Honoraria; Dava Oncology: Honoraria; Celgene/BMS: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Abbvie: Honoraria. Drgona: Abbvie: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Roche: Honoraria, Speakers Bureau; Sandoz: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Teva: Honoraria; Viatris: Honoraria. Hawkes: Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Merck KgA: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Specialised Therapeutics: Consultancy; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Speakers Bureau; Regeneron: Speakers Bureau; Antigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Levi: AbbVie: Consultancy, Research Funding. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Sportelli: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor: Myeloid Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Mundipharma: Consultancy; Nomocan: Consultancy; Kymera: Consultancy, Current equity holder in publicly-traded company; TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Dren: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Fowler: Bristol Myers Squibb, F. Hoffmann-La Roche Ltd, TG Therapeutics and Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; BostonGene, Corp: Current Employment, Current holder of stock options in a privately-held company. Zinzani: ROCHE: Other, Speakers Bureau; NOVARTIS: Consultancy, Other, Speakers Bureau; GILEAD: Other: Advisory board, Speakers Bureau; KYOWA KIRIN: Other, Speakers Bureau; SANDOZ: Other: Advisory board; BMS: Other: Advisory board, Speakers Bureau; Incyte: Other, Speakers Bureau; JANSSEN-CILAG: Other: Advisory board, Speakers Bureau; CELLTRION: Other: Advisory board, Speakers Bureau; VERASTEM: Consultancy, Other: Advisory board, Speakers Bureau; SERVIER: Other: Advisory board, Speakers Bureau; TAKEDA: Other: Advisory board, Speakers Bureau; Beigene: Other, Speakers Bureau; MSD: Consultancy, Other: Advisory board, Speakers Bureau; TG Therapeutics: Other: Advisory board, Speakers Bureau; EUSAPHARMA: Consultancy, Other, Speakers Bureau; ADC Therap.: Other.

Background: Umbralisib, a selective PI3Kδ and casein kinase-1epsilon (CK1ε) inhibitor, is pharmacologically distinct from other PI3K inhibitors and is administered orally once daily. Ublituximab is a novel anti-CD20 monoclonal antibody glycoengineered for enhanced antibody-dependent cellular cytotoxicity that targets a unique epitope on CD20. The primary analysis of the randomized, multicenter, Phase 3 UNITY-CLL trial (NCT02612311) demonstrated that the umbralisib+ublituximab (U2) combination prolonged progression-free survival (PFS) compared to chemoimmunotherapy in both treatment-naïve (TN) and previously treated (PT) populations (Gribben et al. 2020). Herein, results are presented for patients treated with U2 by treatment status. Methods: Patients ≥18 years of age with TN or PT CLL requiring treatment, per iwCLL criteria with adequate organ function and ECOG PS ≤2, were eligible. Patients were initially randomized 1:1:1:1 to receive U2, obinutuzumab+chlorambucil (O+Chl), umbralisib monotherapy, or ublituximab monotherapy. Stratification factors included treatment status (treatment-naïve vs. previously treated) and deletion 17p status. Umbralisib was administered orally at 800 mg once daily until progression or removal from treatment for other reasons. Ublituximab was administered intravenously at 900 mg on Days 1/2 [split 150/750 mg], 8, and 15 of Cycle 1, Day 1 of Cycles 2 - 6, and on Day 1 every 3 cycles after Cycle 6. The primary endpoint was independent review committee (IRC)-assessed PFS of U2 compared to O+Chl. Key secondary endpoints included IRC-assessed overall response rate (ORR), complete response, undetectable minimal residual disease (uMRD), duration of response, and safety, assessed from the first dose until 30 days after the last dose of study medication. While the primary analysis reported results for the pooled intent-to-treat population, the current analysis focuses on outcomes in patients treated with U2 by treatment status. Results: At data cut-off date of May 1, 2020, U2-treated patients had a median follow-up of 35.27 months. Of the 210 patients treated with U2, 119 were TN and 91 were PT. TN patients had a median age of 68 years (39 - 88 years) and 63% were male. Median PFS for U2 in TN patients was 38.5 mos (95% CI, 33.2, NE) with an estimated 24-mo PFS rate of 76.6%. IRC-assessed ORR was 84.0% (95% CI, 77.5%-90.6%). The median duration of exposure to umbralisib and ublituximab was 26.5 and 29.5 mos, respectively. In TN patients, AEs of special interest (AESI) of grade ≥3 included: neutropenia (24.1%), diarrhea (13.8%), ALT increased (12.1%), AST increased (7.8%), non-infectious colitis (2.6%), infusion-related reaction (IRR, 0.9%), and pneumonitis (0.9%). Discontinuation of either study drug due to these grade ≥3 AESI occurred in 5.2% (neutropenia), 2.6% (diarrhea), 3.4% (ALT increase), 1.7% (AST increase), 1.7% (colitis), 0.9% (IRR), and 0.9% (pneumonitis) of patients. PT patients had a median of 2 prior (1 - 9) lines of therapy, the median age was 65 years (43 - 87 years) and 65.9% were male. Median PFS was 19.5 mos (95% CI, 14.6-27.7) with an estimated 24-mo PFS rate of 41.3%. The IRC-assessed ORR was 82.4% (95% CI, 74.6%-90.2%). Among 14 patients previously treated with ibrutinib, the ORR was 57%. The median duration of exposure to umbralisib and ublituximab were 15.6 mos and 14.6 mos, respectively. In PT patients, AESI of grade ≥3 included: neutropenia (40.0%), diarrhea (10.0%), IRR (3.3%), ALT increase (3.3%), AST increase (2.2%), and non-infectious colitis (2.2%). Discontinuation of either study drug due to these grade ≥3 AESI occurred in 1.1% (ALT increase), 1.1% (AST increase), and 1.1% (colitis) of patients. Conclusions: U2 demonstrated a tolerable safety profile in both the TN and PT populations. These results mark the first randomized Phase 3 trial of a PI3K in TN CLL, establishing a new mechanism of action in this setting. Disclosures Jacobs: Genentech: Consultancy; Jannsen: Speakers Bureau; TG Therapeutics: Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; Verastem: Consultancy; AbbVie: Consultancy, Speakers Bureau; SecuraBio: Consultancy, Speakers Bureau; TeneoBio: Research Funding; MEI Pharma: Research Funding; Adaptive Biotechnologies: Consultancy; ADC Therapeutics: Consultancy. Jurczak: Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Research Funding; Morphosys: Research Funding; Mei Pharma: Research Funding; Merck: Research Funding; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Epizyme: Research Funding; Debbiopharm: Research Funding; Celgene: Research Funding; Celtrion: Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding; Sandoz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; TG Therapeutics: Research Funding. Flinn: ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Giannopoulos: Sandoz: Consultancy, Honoraria; Pfizer: Honoraria; Teva: Honoraria; Karyopharm: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Bei-Gene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; TG Therapeutics: Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Polish Myeloma Consortium, Next Generation Hematology Association: Membership on an entity's Board of Directors or advisory committees; Sanofi-Genzyme: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding. Wróbel: Novartis: Honoraria, Speakers Bureau; BMS: Honoraria; Roche: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; BeiGene: Honoraria. Cultrera: Beigene: Research Funding. Danilov: Gilead Sciences: Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Rigel Pharm: Honoraria; Bayer Oncology: Consultancy, Honoraria, Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding; SecuraBio: Research Funding; Genentech: Consultancy, Honoraria, Research Funding. Burke: Kymera: Consultancy; Adaptive Biotechnologies: Consultancy; Beigene: Consultancy, Speakers Bureau; Epizyme: Consultancy; AbbVie: Consultancy; MorphoSys: Consultancy; Verastem: Consultancy; Bristol Myers Squibb: Consultancy; Kura: Consultancy; Roche/Genentech: Consultancy; AstraZeneca: Consultancy; SeaGen: Consultancy, Speakers Bureau; X4 Pharmaceuticals: Consultancy. Goldschmidt: Ontada: Current Employment; Blue Ridge Cancer Care: Current Employment; Amgen: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; TG Therapeutics: Honoraria; G1 Therapeutics: Honoraria, Speakers Bureau. Beach: TG Therapeutics: Speakers Bureau. Huntington: TG Therapeutics: Research Funding; DTRM Biopharm: Research Funding; AbbVie: Consultancy; AstraZeneca: Consultancy, Honoraria; Flatiron Health Inc.: Consultancy; Bayer: Honoraria; Servier: Consultancy; Genentech: Consultancy; Novartis: Consultancy; Thyme Inc: Consultancy; SeaGen: Consultancy; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Research Funding. Pinilla Ibarz: Sellas: Other: ), patents/royalties/other intellectual property; AbbVie, Janssen, AstraZeneca, Takeda: Speakers Bureau; AbbVie, Janssen, AstraZeneca, Novartis, TG Therapeutics, Takeda: Consultancy, Other: Advisory; MEI, Sunesis: Research Funding. Sharman: TG Therapeutics: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy; BeiGene: Consultancy; AstraZeneca: Consultancy; Centessa: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Lilly: Consultancy; AbbVie: Consultancy. Siddiqi: AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Juno therapeutics: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; BeiGene: Other: DSM Member, Speakers Bureau; PCYC: Speakers Bureau; Jannsen: Speakers Bureau; Dava Oncology: Honoraria; ResearchToPractice: Honoraria. Brander: Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; AstraZeneca: Research Funding; ArQule: Research Funding; DTRM: Research Funding; Ascentage: Research Funding; Genentech: Consultancy, Research Funding; Novartis: Research Funding; TG Therapeutics: Consultancy, Research Funding; AbbVie: Consultancy, Other: informCLL registry steering committee, Research Funding; Verastem: Consultancy; MEI Pharma: Research Funding; LOXO: Research Funding; NCCN: Other: panel member; ArQule/Merck: Consultancy; Juno Therapeutics/Celgene/Bristol Myers Squibb: Research Funding; BeiGene: Research Funding; Pfizer: Consultancy, Other: Biosimilars outcomes research panel. Shadman: Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune , Mustang Bio and Atara Biotherapeutics: Consultancy; Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding. Pagel: AstraZeneca: Consultancy; Gilead: Consultancy; Pharmacyclics/AbbVie: Consultancy; Incyte/MorphoSys: Consultancy; Actinium Pharmaceuticals: Consultancy; Kite, a Gilead Company: Consultancy; MEI Pharma: Consultancy; Epizyme: Consultancy; BeiGene: Consultancy. Dlugosz-Danecka: Janssen: Consultancy, Research Funding; Roche: Consultancy, Research Funding, Speakers Bureau; Servier: Consultancy, Speakers Bureau; Acerta Pharma: Research Funding; AbbVie: Research Funding; Macrogenics: Research Funding; Beigene: Research Funding; MEI Pharma: Research Funding; Incyte Corp.: Research Funding; Takeda: Research Funding. Ghosh: Janssen: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Karyopharma: Consultancy, Honoraria; Genentech: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; Genmab: Consultancy, Honoraria; Adaptive Biotech: Consultancy, Honoraria; AbbVie: Honoraria, Speakers Bureau. Kolibaba: TG Therapeutics: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Atara Biotechm: Consultancy; McKesson Specialty Health: Consultancy; Sunitomo Dainippon Pharma: Consultancy; Tolero Pharma: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Sportelli: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. O'Connor: Mundipharma: Consultancy; Nomocan: Consultancy; Kymera: Consultancy, Current equity holder in publicly-traded company; TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Dren: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Myeloid Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Weiss: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Gribben: Takeda: Honoraria; Novartis: Honoraria; Morphosys: Honoraria; Gilead/Kite: Honoraria; BMS: Honoraria; Abbvie: Honoraria; AZ: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; TG Therapeutics: Honoraria.

Background Umbralisib is an oral, once-daily inhibitor of PI3Kδ and CK1e that is highly selective for the delta isoform. The UNITY-NHL trial (NCT02793583) is a multicenter, open-label, Phase 2b study evaluating umbralisib in previously treated NHL patients. Herein, we present results from the UNITY-NHL study. Methods 208 patients with R/R marginal zone, follicular, or small lymphocytic lymphoma (MZL, FL, SLL) unresponsive to prior treatments (≥1 MZL; ≥2 FL/SLL), including ≥1 anti-CD20–based therapy, were administered umbralisib 800mg orally once-daily until disease progression, unacceptable toxicity, or study withdrawal. The primary endpoint of the study was overall response rate (ORR) as assessed by an independent review committee, according to the revised IWG criteria. Results At a median follow up of 27.8 months, MZL patients (n=69) had an ORR of 49.3% (95% CI 37.0% - 61.6%) with 15.9% achieving a complete response (CR), and a Disease Control Rate (DCR: CR+PR+SD) of 82.6%. Median time-to-response (TTR): 2.8 months (95% CI 2.7 - 2.9). No patient who achieved CR has progressed to date. At a median follow up of 27.5 months, FL patients (n=117) had an ORR of 45.3% (95% CI 36.1% - 54.8%) with 5.1% achieving a CR, and a DCR of 79.5%. Median TTR: 4.6 months (95% CI 3.0 - 5.6). At a median follow up of 29.3 months, SLL patients (n=22) had an ORR of 50.0% (95% CI 28.2 - 71.8) with 4.5% achieving a CR, and a DCR of 86.4%. Median TTR: 2.7 months (95% CI 2.4 - 2.8). At least one grade ≥3 treatment-emergent adverse event (TEAE) was reported in 53.4% of patients. TEAEs led to umbralisib discontinuation in 32 patients (15.4%). Grade ≥3 TEAEs reported in ≥10% of patients: neutropenia (11.5%) and diarrhea (10.1%). Increased ALT/AST (grade ≥3) occurred in 6.7%/7.2% of patients. Conclusions Umbralisib achieved meaningful clinical activity in a heavily pretreated iNHL population. The safety profile was manageable, with a relatively low incidence of immune-mediated toxicities and AE-related discontinuations. These results suggest umbralisib has a favorable benefit-risk profile in this patient population and have supported the Accelerated Approval of umbralisib in previously treated MZL and FL patients.

Background: Umbralisib is an oral, once-daily, dual inhibitor of phosphatidylinositol-3-kinase-delta (PI3Kδ) and casein kinase-1ε (CK1ε) that exhibits improved selectivity for the delta isoform of PI3K. The UNITY-NHL trial (NCT02793583) is a multicenter, open-label, registration directed Phase 2 study designed to evaluate the safety and efficacy of umbralisib in previously treated NHL patients (pts). Previously reported results in pts with relapsed/refractory (R/R) marginal zone lymphoma (MZL) demonstrated that umbralisib was active with a manageable safety profile. In contrast with other PI3K inhibitors, there was a low incidence of immune-mediated toxicities with umbralisib, possibly attributable to enhanced selectivity for the PI3Kδ isoform as well as inhibition of CK1ε. Herein, we present results from the final analysis of the iNHL population treated with single agent umbralisib. Methods: Eligible pts had histologically confirmed iNHL: MZL (splenic, nodal, extranodal), follicular lymphoma (FL; Gr 1, 2, 3a), or small lymphocytic lymphoma (SLL). MZL pts were R/R to ≥1 prior lines of treatment, which must have included an anti-CD20, while FL and SLL pts were R/R to ≥2 prior lines, which had to include an anti-CD20 and an alkylating agent. Umbralisib was administered orally at 800 mg once-daily in 28-day treatment cycles until disease progression or unacceptable tolerability. The primary endpoint of the study was overall response rate (ORR) as assessed by an independent review committee (IRC), according to the revised IWG criteria (Cheson 2007). Secondary endpoints included duration of response (DoR), progression-free survival (PFS), time to response (TTR), and safety. Pneumocystis jiroveci pneumonia (PCP) and anti-viral prophylaxis were mandated for all pts. Results: 208 iNHL pts received at least 1 dose of umbralisib, including 69 MZL, 117 FL, and 22 SLL pts. The median duration of exposure was 8.4 mos (range 0.2 - 27.0), median age was 66, and 56.7% were male. Pts had received a median of 2 prior regimens (range 1 - 10) with 46.1% having received ≥ 3 regimens. FL patients had a median of 3 prior regimens. With a median follow up of 27.8 mos, MZL pts had an ORR of 49.3% (95% CI 37.0% - 61.6%) with 15.9% achieving a complete response (CR), and a Disease Control Rate (DCR: CR+PR+SD) of 82.6%. ORR was consistent amongst MZL subtypes. The median TTR was 2.8 months (95% CI 2.7 - 2.9). The median profession-free survival (PFS) was not reached (95% CI 12.1 mos - not evaluable [NE]) with an estimated 12-month PFS rate of 64.2%. The median DoR was not reached (95% CI 10.3 mos - NE), and no pts who achieved CR have experienced disease progression to date. With a median follow up of 27.5 mos, FL pts had an ORR of 45.3% (95% CI 36.1% - 54.8%) with 5.1% achieving a CR, and a DCR of 79.5%. The median TTR was 4.6 mos (95% CI 3.0 - 5.6). The median PFS was 10.6 mos (95% CI 7.2 - 13.7) with an estimated 12-month PFS rate of 45.9%. The median DoR was 11.1 mos (95% CI 8.3 - 15.6). With a median follow up of 29.3 mos, SLL pts had an ORR of 50.0% (95% CI 28.2 - 71.8) with 4.5% achieving a CR, and a DCR of 86.4%. The median TTR was 2.7 mos (95% CI 2.4 - 2.8). The median PFS was 20.9 mos (95% CI 7.4 - 24.1) with an estimated 12-month PFS rate of 62.6%. The median DoR was 18.3 mos (95% CI 2.4 - NE). Best % change in target lesions form baseline for pts with at least one post-baseline assessment is shown in the figure. At the data cut-off, 60 pts (26 MZL, 27 FL, 7 SLL) remained on treatment. The most common ≥G3 AEs were neutropenia (11.5%), diarrhea (10.1%) and increased ALT/AST (7.2%). Other AEs of interest included pneumonitis (All G 1.4%; ≥G3 1.0%), and colitis (All G 1.4%; ≥G3 0.5%). Serious AEs were reported in 28.1% of pts, with 24.6% ≥G3. One patient with SLL had a fatal myocardial infarction (unrelated to umbralisib); there were no other G5 AEs. A total of 31 pts (14.9%) discontinued due a treatment-related adverse event (AE). Treatment-related AEs leading to dose reductions occurred in 20 (9.6%) pts. Conclusions: In the Phase 2 UNITY-NHL study, umbralisib achieved meaningful clinical activity in a heavily pretreated iNHL population. The safety profile was manageable, with a relatively low incidence of immune-mediated toxicities and AE-related discontinuations. These results suggest umbralisib has a favorable benefit-risk profile in this patient population and further development is ongoing. Figure Disclosures Zinzani: Kirin Kyowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Consultancy, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Eusapharma: Consultancy, Speakers Bureau; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics, Inc.: Honoraria, Speakers Bureau; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Jurczak:Sandoz-Novartis: Consultancy; Afimed: Research Funding; Acerta: Consultancy, Research Funding; Pharmacyclics: Research Funding; Bayer: Research Funding; Maria Sklodowska-Curie National Research Institute of Oncology, Krakow, Poland: Current Employment; TG Therapeutics, Inc.: Research Funding; Celgene: Research Funding; Servier: Research Funding; Takeda: Research Funding; Roche: Research Funding; Merck: Research Funding; MEI Pharma: Research Funding; Janssen China R&D: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; AstraZeneca: Consultancy; European Medicines Agency,: Consultancy; Jagiellonian University, Krakow, Poland: Ended employment in the past 24 months; Epizyme: Consultancy; Gilead Sciences: Research Funding; MorphoSys: Research Funding; Nordic Nanovector: Research Funding. Ghosh:Kite/Gilead: Consultancy, Speakers Bureau; Juno/Celgene/Bristol-Myers Squibb: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; SGN: Consultancy, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Research Funding; Roche/Genentech: Research Funding; Karyopharm: Consultancy; Genmab: Consultancy, Speakers Bureau; AbbVie: Speakers Bureau; AstraZeneca: Speakers Bureau; Celgene/Bristol-Myers Squibb: Speakers Bureau; Forty Seven Inc: Consultancy, Other: Research Bureau, Research Funding; Janssen: Consultancy, Research Funding, Speakers Bureau. Derenzini:TG Therapeutics, Inc.: Research Funding. Cheah:Celgene, F. Hoffmann-La Roche, MSD, Janssen, Gilead, Ascentage Pharma, Acerta, Loxo Oncology, TG therapeutics: Honoraria; Celgene, F. Hoffmann-La Roche, Abbvie, MSD: Research Funding. Phillips:Karyopharm: Consultancy; Beigene: Consultancy; Seattle Genetics: Consultancy; BMS: Consultancy; Abbvie: Consultancy, Research Funding; AstraZeneca: Consultancy; Incyte: Consultancy, Other: travel expenses; Cardinal Health: Consultancy; Bayer: Consultancy, Research Funding; Pharmacyclics: Consultancy. Lech-Marańda:Roche, Amgen, Gilead: Speakers Bureau; Roche, Novartis, Takeda, Janssen-Cilag, Amgen, Gilead, AbbVie, Sanofi: Consultancy. Cheson:Abbvie: Consultancy, Research Funding; Kite: Consultancy; TG Therapeutics: Speakers Bureau; Morphosys: Consultancy; Symbio: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Research Funding; Jannsen: Consultancy; Parexel: Consultancy; Trillium: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees. Caimi:Verastem: Other: Advisory Board; Celgene: Speakers Bureau; Amgen: Other: Advisory Board; Bayer: Other: Advisory Board; Kite Pharma: Other: Advisory Board; ADC Therapeutics: Other: Advisory Board, Research Funding. Leslie:BeiGene: Honoraria, Speakers Bureau; KitePharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Speakers Bureau; Celgene: Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Chavez:Karyopharm: Consultancy; BeiGene: Speakers Bureau; Bayer: Consultancy; Merck: Research Funding; AbbVie: Consultancy; Genentech: Speakers Bureau; Epizyme: Speakers Bureau; Gilead: Consultancy; Novartis: Consultancy; Kite, a Gilead Company: Consultancy, Speakers Bureau; Celgene: Consultancy; Morphosys: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; Verastem: Consultancy; Pfizer: Consultancy. Fonseca:Bristol-Myers Squibb Company: Speakers Bureau. Babu:Merck: Research Funding; Syndax: Research Funding; AbbVie: Research Funding; Janssen Oncology: Research Funding; TG Therapeutics: Research Funding; Amgen: Research Funding; Sanofi: Research Funding; Lutheran Hospital: Other; Argenx: Consultancy, Research Funding; Nektar: Research Funding; Novartis: Research Funding; Bayer: Honoraria; Lilly: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Alexion Pharmaceuticals: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Fort Wayne Medical Oncology & Hematology: Current Employment, Current equity holder in publicly-traded company; AstraZeneca/MedImmune: Research Funding; AstraZeneca: Consultancy, Honoraria; Genentech, Inc./ F. Hoffmann-La Roche: Research Funding; Boehringer Ingelheim: Consultancy. Hodson:Gilead Sciences: Research Funding. Burke:Bristol Myers Squibb: Consultancy; Verastem: Consultancy; Bayer: Consultancy; Astra Zeneca: Consultancy; Gilead: Consultancy; Seattle Genetics: Speakers Bureau; AbbVie: Consultancy; Morphosys: Consultancy; Adaptive: Consultancy; Epizyme: Consultancy; Kura: Consultancy; Celgene: Consultancy; Adaptive Biotechnologies: Consultancy; Roche: Consultancy. Sharman:TG Therapeutics: Consultancy, Research Funding; Bristol Meyers Squibb: Consultancy, Research Funding; BeiGene: Research Funding; Genentech: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Acerta: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. O'Connor:Kymera Therapeutics: Current equity holder in private company, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Other: Data Safety Monitoring Committee, Research Funding; TG Therapeutics: Current Employment, Current equity holder in publicly-traded company; Servier: Consultancy; Mundipharma: Other: Consulting; Nomocan: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Astex Pharmaceuticals: Honoraria, Research Funding. Miskin:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Sportelli:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Weiss:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Fowler:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Background: Despite the effectiveness of novel agents in treating CLL, prolonged single agent use can lead to drug resistance, toxicity, challenges with adherence, and considerable financial burden. Combinations may provide deeper prolonged remissions using defined treatment durations. Umbralisib (Umbra) is a novel and highly specific PI3Kδ/CK1ε dual inhibitor, while ublituximab (Ubli) is a glycoengineered monoclonal antibody targeting a unique epitope on CD20. A randomized Phase 3 study of the Umbra + Ubli (U2) combination in patients (pts) with treatment naïve and previously treated CLL, UNITY-CLL, was recently determined to have met its primary endpoint at a pre-planned interim analysis. Integrating the BCL2 inhibitor venetoclax (Ven) into the U2 backbone is hypothesized to reduce the risk of acquired drug resistance (Choudhary, Cell Death Dis 2015), achieve higher levels of undetectable minimal residual disease (MRD), and reduce the risk of tumor lysis syndrome (TLS). Phase 1 results established the recommended Phase 2 doses to be: Umbra 800 mg QD; Ubli 900 mg and Ven 400 mg QD (Barr et al., ASH 2019). The Phase 2 component evaluated the safety, efficacy and MRD negativity rates in relapsed or refractory CLL pts. Methods: In Phase 2, pts received three cycles of Umbra 800 mg QD along with Ubli 900 mg, administered weekly during cycle 1 (Day 1/2 split 150/750), then on Day 1 in cycles 2 through 6. Ven is initiated in cycle 4 and increased in standard fashion to 400 mg and continues with umbralisib once-daily through cycle 12. The primary endpoint for Phase 2 was complete remission (CR) rate by iwCLL criteria. Undetectable MRD ( Results: 40 pts have been treated to date. Baseline demographics were as follows: male/female (26/14), median age 65 yrs (range 43-83), median # prior therapies 2 (range 1-5). 20 pts (50%) had prior ibrutinib of which 11 (55%) were BTK refractory with BTK resistance mutations found in 8 cases. High-risk genetic features included unmutated IGHV genes (n=20), del17p (n=8), del11q (n=11), TP53 mut (n=4), NOTCH1 mut (n=5) and SF3B1 mut (n=2). Baseline (screening) TLS risk amongst efficacy evaluable pts (n=34) was high (H), medium (M) and low (L) risk in 5, 19 and 10 pts respectively. For all pts treated to date, the most common AEs were (all causality and all grade; >25% of pts) infusion related reactions [IRR] (63%), anemia (55%), thrombocytopenia (53%), neutropenia (53%), leukopenia (50%), creatinine increase, (50%), fatigue (45%), diarrhea (43%), nausea (38%), AST increase (30%). The only grade 3/4 AEs occurring in ≥ 5% of pts were neutropenia (23%) leukopenia (13%) and IRR (8%). Grade ≥ 3 PI3Kδ-associated toxicities of interest occurred in 2 pts (1 G3 colitis, and 1 G3 diarrhea). No TLS events were observed during Ven administration. Discontinuations of any study drug due to AE occurred in 3 pts, of which 1 pt discontinued all 3 agents (G3 diarrhea). Of 34 pts who completed 3 cycles of U2 debulking, TLS risk was substantially reduced: of 5 H-risk pts only 1 remained H-risk; of 19 M-risk pts, only 4 remained M-risk with the remainder at L-risk (79% reduction in H- and M-risk TLS). Among evaluable pts, the overall response rate was 76% (26/34) after cycle 3 (U2 debulking only), 100% (26/26) after cycle 7 and 100% (19/19) after cycle 12. Among the 19 pts who finished 12 cycles of therapy, 8 (42%) achieved CR by iwCLL criteria. Undetectable MRD ( Conclusion: U2-Ven is safe and highly effective in patients with relapsed/refractory CLL. Results suggest that this chemotherapy-free regimen can provide undetectable MRD after only 12 cycles of treatment, representing an effective 12-month treatment option for this population. These data have given rise to the multicenter ULTRA-V study, which is studying the U2-Ven triplet in patients with treatment naïve and relapsed/refractory CLL. Figure Disclosures Barr: Seattle Genetics: Consultancy; Abbvie/Pharmacyclics: Consultancy, Research Funding; TG therapeutics: Consultancy, Research Funding; Verastem: Consultancy; Celgene: Consultancy; Merck: Consultancy; Genentech: Consultancy; Janssen: Consultancy; Morphosys: Consultancy; AstraZeneca: Consultancy, Research Funding; Gilead: Consultancy. Ma:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Bioverativ: Consultancy, Honoraria; BeiGene: Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; TG Therapeutics: Research Funding; Juno: Research Funding; Novartis: Research Funding. Zent:TG Therapeutics, Inc: Research Funding; Acerta / Astra Zeneca: Research Funding; Mentrik Biotech: Research Funding. Liesveld:Abbvie: Honoraria; Onconova: Other: data safety monitoring board. Sportelli:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miskin:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Weiss:TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Friedberg:Acerta Pharma - A member of the AstraZeneca Group, Bayer HealthCare Pharmaceuticals.: Other; Roche: Other: Travel expenses; Seattle Genetics: Research Funding; Astellas: Consultancy; Bayer: Consultancy; Kite Pharmaceuticals: Research Funding; Portola Pharmaceuticals: Consultancy. Hill:Pharmacyclics: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; AstraZenica: Consultancy, Honoraria, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Genentech: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding.

Summary This phase 1/2 study evaluated the safety, pharmacokinetic behavior and anti‐tumour activity of ublituximab, a unique type I, chimeric, glycoengineered anti‐CD20 monoclonal antibody, in rituximab‐relapsed or ‐refractory patients with B‐cell non‐Hodgkin lymphoma (B‐NHL) or chronic lymphocytic leukaemia (CLL). Induction therapy (doses of 450–1200 mg) consisted of 4 weekly infusions in cycle 1 for NHL and 3 weekly infusions in cycles 1 and 2 for CLL. Patients received ublituximab maintenance monthly during cycles 3–5, then once every 3 months for up to 2 years. Enrolled patients with B‐NHL (n = 27) and CLL (n = 8) had a median of 3 prior therapies. No dose‐limiting toxicities or unexpected adverse events (AEs) occurred. The most common AEs were infusion‐related reactions (40%; grade 3/4, 0%); fatigue (37%; grade 3/4, 3%); pyrexia (29%; grade 3/4, 0%); and diarrhoea (26%; grade 3/4, 0%). Common haematological AEs were neutropenia (14%; grade 3/4, 14%) and anaemia (11%; grade 3/4, 6%). The overall response rate for evaluable patients (n = 31) was 45% (13% complete responses, 32% partial responses). Median duration of response and progression‐free survival were 9·2 months and 7·7 months, respectively. Ublituximab was well‐tolerated and efficacious in a heterogeneous and highly rituximab‐pre‐treated patient population.

The novel PI3K-δ inhibitor TGR-1202 enhances Brentuximab Vedotin-induced Hodgkin lymphoma cell death via mitotic arrest

8022 Background: The BTK inhibitor ibrutinib (IB) has advanced the treatment for patients (pts) with CLL, however, among pts with high-risk CLL, disease control with IB is less durable. Ublituximab (UTX) is a glycoengineered mAb with enhanced ADCC. The GENUINE study evaluated the addition of UTX to IB vs. IB alone in high-risk rel/ref CLL. With a median follow up now 3.5+ yrs, we present the final results. Methods: Eligible pts having rel/ref CLL with centrally confirmed del17p, del11q, and/or a TP53 mutation, were randomized 1:1 to IB (420 mg QD) alone or with UTX (900 mg on D1, 8, 15 of Cy 1, D1 of Cy 2-6, and Q3 Cy thereafter). No limit on # of prior Tx; prior IB excluded. Primary endpoint was overall response rate (ORR) by iwCLL 2008 (excludes PR-L); secondary endpoints were CR rate, peripheral blood MRD negativity (analyzed centrally), PFS, and safety. Response was by blinded independent review. Results: 117 pts were treated (59 in UTX + IB arm; 58 in IB arm). Med age was 66 yrs and med # of prior Tx was 1 (range 1-5) for each arm. Baseline features were relatively balanced including ECOG, gender, and med time since diagnosis (6+ yrs). 17p del was greater in the IB arm (50% vs 44%); bulky disease was greater in UTX + IB arm (47% vs 28%); IGHV-unmut was 83% for both arms. At data-cutoff of Sep 1, 2019, AEs were comparable between the arms, except infusion reactions (UTX + IB: All G 53% / G 3/4 3%) and neutropenia (All G 36% vs 21%, G 3/4 19% vs. 12%) which were higher for UTX + IB. At a med follow up of 42 mos, all efficacy endpoints were in favor of UTX + IB (see Table). Conclusions: In contrast to prior studies adding rituximab to IB, GENUINE is the first randomized trial to demonstrate a PFS benefit with the addition of an anti-CD20 to IB. Increasing depth of response (CR rate, MRD-neg) post first year of Tx supports maintenance therapy with UTX. Clinical trial information: NCT02301156 . [Table: see text]

Background:Despite the effectiveness of novel agents in treating CLL, single agent use requires prolonged administration which can lead to drug resistance, toxicity and considerable cost over time. Combinations may provide deeper prolonged remissions using defined treatment durations. Umbralisib (Umbra) is a novel, highly-specific PI3Kδ inhibitor and ublituximab (Ubli) is a chimeric monoclonal antibody targeting a unique epitope on CD20 and glycoengineered to enhance antibody dependent cellular toxicity. Combining these agents with the BCL2 inhibitor venetoclax (Ven) may prevent drug resistance (Choudhary, Cell Death Dis 2015), avoid tumor lysis syndrome (TLS) and achieve undetectable minimal residual disease (MRD). This phase 1/2 trial evaluates the safety and efficacy of Umbra + Ubli + Ven for 12 cycles followed by MRD evaluation in relapsed or refractory CLL patients (pts). Methods:Pts received three 28-day cycles of Umbra daily along with Ubli, administered weekly during cycle 1, then once during cycles 2 and 3, followed by Umbra + Ven for 9 additional cycles. During the phase 1 study, dose levels including Umbra 600mg and 800mg were tested with Ubli 900mg and Ven, increased in standard fashion to 400 mg during cycle 4. The primary endpoint for phase 1 was safety; the primary endpoint for phase 2 was complete remission (CR) rate by iwCLL criteria. MRD negativity ( Results: 21 pts have been treated to date: 9 in phase 1 and 12 in phase 2. Baseline demographics were as follows: male/female (12/9), median age 65 yrs (range 49-83), median prior therapies 2 (1-5). 9 pts had prior ibrutinib of which 4 were BTK inhibitor refractory. BTK resistance mutations were found in 2 pts. High risk genetic features included unmutated IGHV genes (11 pts), del17p or del11q (7 pts), TP53 mut (1 pt), NOTCH1 mut (4 pts) and SF3B1 mut (1 pt). Baseline TLS risk was high, medium and low risk in 2, 12 and 7 pts respectively. During dose escalation, 3 pts were treated using Umbra 600mg and subsequently 6 pts using Umbra 800mg. No DLTs occurred, and the MTD was not reached. As such, the phase 2 dose used was Ubli 900 mg + Umbra 800 mg with venetoclax, undergoing ramp up to 400 mg. For all pts treated to date, the most common AEs were (all causality and all grade; >20% of pts) infusion reactions (62%), thrombocytopenia (57%), neutropenia (52%), anemia (52%), fatigue (52%), ALT or AST increase (43%), nausea (33%), diarrhea (29%) and headache (24%). Grade 1 creatinine increase, hypocalcemia and hyperkalemia were observed in 12 (57%), 6 (29%) and 5 (24%) of pts respectively. These AEs predominately occurred outside of venetoclax ramp up. Grade 3/4 AE's occurring in ≥ 2 pts included neutropenia (n=4, 19%), infusion reaction (n=2, 10%) and thromboembolism (n=2, 10%). No grade ≥ 3 PI3Kδ-associated toxicities were noted (0 events of pneumonitis, colitis or grade 3/4 transaminitis). No events of TLS were observed. One pt discontinued study treatment due to grade 3 rash. All pts were converted to low TLS risk after 3 cycles of Umbra + Ubli, except for 1 pt who remained medium risk after discontinuing Ubli secondary to a grade 3 infusion reaction, allowing outpatient venetoclax initiation in all pts. In evaluable pts, the overall response rate was 85% (11/13) after cycle 3, 100% (9/9) after cycle 7 and 100% (5/5) after cycle 12. Of the 5 pts who finished 12 cycles of therapy, a median reduction in nodal disease of 87% occurred resulting in 2 CRs and 3 PRs by iwCLL criteria. 4 pts have undetectable MRD ( Conclusion: We established the phase 2 dose of Umbra + Ubli + Ven and demonstrated good tolerability in pts with relapsed or refractory CLL. Preliminary results suggest that this chemotherapy-free regimen can provide undetectable MRD after only 12 cycles, representing an effective treatment plan for this population. Ongoing enrollment is focused on pts who have relapsed after BTK inhibitors and a multi-center trial is planned to further develop the triplet regimen. Figure Disclosures Barr: Gilead: Consultancy; AbbVie: Consultancy; Janssen: Consultancy; Verastem: Consultancy; Seattle Genetics: Consultancy; Celgene: Consultancy; Merck: Consultancy; Genentech: Consultancy; Astra Zeneca: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie company: Consultancy, Research Funding. Hill:TG therapeutics: Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Research Funding; Kite: Consultancy, Honoraria; Amgen: Research Funding; Takeda: Research Funding; Seattle Genetics: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Honoraria; Celegene: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Ma:Janssen: Consultancy, Speakers Bureau; Beigene: Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Novartis: Research Funding; Xeme: Research Funding; Juno: Research Funding; Incyte: Research Funding; Kite: Consultancy; Genentech: Consultancy; Acerta: Research Funding; Bioverativ: Consultancy; Astra Zeneca: Consultancy, Research Funding, Speakers Bureau; Abbvie: Research Funding; Gilead: Research Funding. Liesveld:Abbvie: Membership on an entity's Board of Directors or advisory committees; Onconova: Other: Data safety monitoring board. Sportelli:TG Therapeutics: Employment. Miskin:TG therapeutics Inc.: Employment, Equity Ownership. Weiss:TG Therapeutics: Employment. Friedberg:Acerta: Other: Data & Safety Monitoring Committee; Bayer: Honoraria, Other: Data & Safety Monitoring Committee. Zent:Astra Zeneca: Research Funding; Mentrik Biotech: Research Funding. OffLabel Disclosure: umbralisib and ublituximab as treatment of CLL

Background: Rituximab (RTX) alone or in combination with chemotherapy has substantially improved treatment outcomes for patients (pts) with marginal zone lymphoma (MZL), but relapse is common and not all pts are acceptable candidates for, or respond to, current salvage therapies. Umbralisib is a novel, next-generation PI3K-delta inhibitor with unique inhibition of casein kinase-1ϵ (CK1ϵ) and, compared to earlier generation PI3K-delta inhibitors, exhibits a differentiated tolerability profile with reduced rates of immune-mediated toxicity (Burris et al, 2018). This registration-directed study evaluates the efficacy and safety of umbralisib in pts with relapsed/refractory (R/R) MZL. Methods: Pts had histologically confirmed MZL, ECOG PS ≤2, and had previously received ≥1 prior therapy including at least one CD20 monoclonal antibody (mAb)-containing regimen. All pts received umbralisib 800 mg orally once daily until progression or unacceptable toxicity. The primary study endpoint was overall response rate (ORR) as assessed by an independent review committee (IRC) according to 2007 IWG criteria. ORR by investigator assessment is reported here, and ORR by IRC is forthcoming. Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and safety. Results: Sixty-nine pts were enrolled; we report on the first 38 who are eligible for at least 6 months (mos) of follow-up as of the data cutoff date. Disease status for the 38 pts: extranodal (n=23), nodal (n=8), and splenic (n=7). Median age was 67 years (range, 34-81). Median number of prior systemic therapies was 2 (range, 1-5). Seven pts (18%) had received monotherapy RTX only, and 26 (68%) had received at least one CD20 mAb-containing chemoimmunotherapy. As of the cut-off date, the median follow-up was 9.6 mos. Per investigator assessment, ORR was 55% (4 CRs and 17 PRs), 29% of pts (n=11) had stable disease (SD) of which 6 of these SD pts remain on study with durations ranging from 7-12+ mos. The clinical benefit rate (CR+PR+SD) was 84%, and 91% of pts with at least 1 post-baseline assessment experienced tumor reductions. The median time to initial response was 2.7 mos, while the median DOR was not reached (95% CI: 8.4-not reached). The 12-month PFS was 71%. The most common (≥20%) adverse events (AE) of any grade included: diarrhea (45%), nausea (29%), fatigue (26%), headache (26%), cough (24%), and decreased appetite (21%). The most common Grade 3/4 events were neutropenia (8%), febrile neutropenia (5%), and diarrhea (5%). As of the cutoff date, 16 pts discontinued treatment (PD: 18%; AEs: 8%; pt decision: 8%; physician decision: 8%) and 58% continue treatment. Conclusions: PI3K-delta inhibition with single-agent umbralisib is active and well tolerated in pts with R/R MZL, achieving durable responses with chemotherapy-free therapy. Citation Format: Nathan H. Fowler, Felipe Samaniego, Wojciech Jurczak, Ewa Lech-Maranda, Nilanjan Ghosh, Bertrand Anz, Piers Patten, James A. Reeves, Lori A. Leslie, Piotr Smolewski, Julio C. Chavez, Paolo Ghia, Corrado Tarella, John M. Burke, Jeff Sharman, Kathryn Kolibaba, Owen A. O'Connor, Chan Y. Cheah, Hari P. Miskin, Peter Sportelli, Michael S. Weiss, Pier Luigi Zinzani. Umbralisib monotherapy demonstrates efficacy and safety in patients with relapsed/refractory marginal zone lymphoma: A multicenter, open-label, registration directed Phase II study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT132.

Introduction: Umbralisib (UMB) is a next generation, once daily, PI3Kδ/CK1ε inhibitor, active in patients with relapsed or refractory (rel/ref) hematologic malignancies that, in long-term follow-up, has demonstrated a uniquely differentiated safety profile from prior PI3Kδ inhibitors (Davids, 2018). Ublituximab (UTX) is a novel glycoengineered mAb targeting a unique epitope on the CD20 antigen. Bendamustine (Benda) is an active chemotherapy agent in pts with lymphoma. The combination of UMB + UTX (U2) is tolerable and active in patients with rel/ref hematologic malignancies and registration directed trials for patients with CLL & NHL are ongoing. This Phase 1 trial evaluates the safety and efficacy of U2 + Benda in patients with advanced diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Methods: Eligible patients had rel/ref DLBCL or FL with an ECOG PS ≤ 2 w/o limit to number of prior therapies. ANC of ≥ 750 and Platelets ≥ 50,000 were required; no growth factor support was permitted in Cycle 1 (cohort escalation group only). Patients refractory to prior PI3Kδ, Benda, or anti-CD20's were eligible. UTX was dosed on Days 1, 8, 15 of Cycle 1, Day 1 of Cycle 2-6, followed by Cycle 9 & 12. UMB was started at 800 mg QD with a -1 dose reduction cohort at 600 mg if not tolerated in ≥ 2/6 patients. Benda was dosed at 90 mg/m2 on Days 1 & 2 of Cycles 1-6 only. Primary endpoints included safety and efficacy (Cheson 2007). Results: Thirty-nine patients were evaluable for safety: 26 DLBCL and 13 FL. Med age 67 yo (range 31-81); 23 M/16 F; median prior treatment regimens = 2 (range 1-6); 22 pts (56%) were refractory to prior treatment and 6 patients had progressed post-transplant; ECOG PS 0/1/2 (12/25/2). Initially 2/4 patients at 800 mg UMB experienced AE's in Cycle 1 that led to treatment interruption (rash, neutropenia) thus the 600 mg dose of TGR-1202 was explored. No additional Cycle 1 treatment delays were reported at the 600 mg dose level, which was later expanded and the 800 mg UMB dose was evaluated with the use of growth factor support in cycle 1 permitted. The most common AE's regardless of causality included diarrhea (54%; G3/4 15%), nausea (49%; G3/4 5%), vomiting (38%; G3/4 0%), neutropenia (33%; G3/4 33%) and pyrexia (31%; G3/4 0%). Thirty-eight patients (25 DLBCL/13 FL) were evaluable for efficacy (1 DLBCL patient came off study for G4 neutropenia prior to first assessment). ORR in the respective groups is shown in Table 1. The median time to response was 8 weeks. The median DOR was 9.6 months (95% CI: 2.5-NR) for patients with DLBCL, and was not reached (95% CI: 8.0-NR) for patients with FL, at a median duration of follow-up for responders of 11.5 months (range 2.9 - 30+ mos). Conclusions: The combination of U2 + bendamustine has exhibited manageable toxicity with significant activity in advanced DLBCL and FL patients, including an encouraging CR rate in advanced patients. Based upon the early activity of the triplet, a registration directed study is underway for patients with rel/ref DLBCL (UNITY-NHL). Disclosures Lunning: Gilead: Consultancy; Astra-Zeneca: Consultancy; Genentech: Consultancy; Spectrum: Consultancy; TG Therapeutics: Consultancy; Bayer: Consultancy; Celgene: Consultancy; AbbVie: Consultancy; Genzyme: Consultancy; Kite: Consultancy; Juno: Consultancy; Genentech: Consultancy; Portola: Consultancy; Janssen: Consultancy; Seattle Genetics: Consultancy; Verastem: Consultancy. Siddiqi:Juno Therapeutics: Other: Steering committee. Flowers:Abbvie: Research Funding; TG Therapeutics: Research Funding; Gilead: Research Funding; Eastern Cooperative Oncology Group: Research Funding; National Cancer Institute: Research Funding; Genentech/Roche: Research Funding; Genentech/Roche: Consultancy; Pharmacyclics: Research Funding; V Foundation: Research Funding; Abbvie: Consultancy, Research Funding; Bayer: Consultancy; Karyopharm: Consultancy; Burroughs Wellcome Fund: Research Funding; Celgene: Research Funding; BeiGene: Research Funding; Gilead: Consultancy; Millennium/Takeda: Research Funding; OptumRx: Consultancy; Pharmacyclics/ Janssen: Consultancy; Spectrum: Consultancy; Janssen Pharmaceutical: Research Funding; Denovo Biopharma: Consultancy; Acerta: Research Funding. Cohen:Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Janssen: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioInvent: Consultancy; Takeda: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BioInvent: Consultancy. Blumel:TG Therapeutics, Inc.: Consultancy. Cutter:TG Therapeutics, Inc.: Consultancy. Pauli:TG Therapeutics, Inc.: Consultancy. Sportelli:TG Therapeutics: Employment, Equity Ownership. Miskin:TG Therapeutics: Employment, Equity Ownership. Weiss:TG Therapeutics: Employment, Equity Ownership. Vose:Kite Pharma: Research Funding; Legend Pharmaceuticals: Honoraria; Roche: Honoraria; Incyte Corp.: Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria; Seattle Genetics, Inc.: Research Funding; Merck Sharp & Dohme Corp.: Research Funding; Acerta Pharma: Research Funding; Epizyme: Honoraria; Celgene: Research Funding.

Introduction: Preclinical data suggest that PD-1 and PD-L1/PD-L2 mediate immune evasion in CLL. However, clinical data (Ding, BLOOD 2017) demonstrate that pembrolizumab monotherapy (pembro) is ineffective in relapsed/refractory (r/r) CLL patients (pts) (ORR 0%, med PFS 2.4 months). Additional data with an anti-PD1 demonstrated a 90% failure rate in Richter's Transformation (RT) with a med 2-month OS (Rogers, BJH 2018). Combinations may represent the future of anti-PD-1 therapy in CLL/RT, especially in RT pts rel/ref to ibrutinib, where median OS is ~3.5 mos. We hypothesized synergistic activity with PD-1 + PI3K blockade. Umbralisib (UMB), is a highly-specific PI3K-δ inhibitor with additional effects on casein kinase-1 epsilon (CK-1ε), which may have an inhibitory effect on Treg function (Deng et al, 2016). We tested the safety and activity of UMB in combination with the anti-CD20 mAb ublituximab (UTX) and pembro in r/r CLL and RT - the first reported combination of a PD-1 inhibitor + PI3K-δ inhibitor in this population. Methods: Ph I (3+3 design), multicenter study to assess the safety/efficacy of UMB + UTX + pembro in pts with r/r CLL and RT. Treatment for CLL pts involved three stages: Induction: UMB (800mg daily) and UTX (900mg 3 out of 4 wks) for the first two 28-day cycles. Consolidation: Pembro (dose level 1=100mg, dose level 2=200mg) was then initiated every 3 wks in combination with UMB and UTX (900mg week 2 of cycle 4 and 6) for cycles 3-6. Maintenance: Cycle > 6, UMB 800 mg daily until progressive disease (PD) or unacceptable AE. For RT pts, all study drugs are started in cycle 1 with the following schedule: UMB 800 mg daily; UTX 900 mg cycle 1 (D1, 8, 15), D1 cycles 2-4, cycle 7 and q3 cycles thereafter; and pembro D3 of cycle 1 and D2 of cycles 2-4. The primary endpoint is safety of the triple combination with efficacy as a secondary endpoint. Response assessments for CLL, based on the iwCLL 2008 criteria, were performed after cycles 2, 6 and 12. RT response assessments (Cheson 2007) were completed at the end of cycles 2, 4 and every 3 cycles until month 12. Peripheral blood and/or bone marrow biopsy, enriched for mononuclear cells, were obtained for correlative analyses at screening, month 2 and 6. Results: Fourteen pts have been treated to date: 9 with CLL (3 at 100 mg pembro / 6 at 200 mg pembro) and 5 with RT (4 at 100 mg pembro / 1 at 200 mg). Baseline demographics were as follows: male/female (9/5), med age 71 yrs (range 60-81), med prior therapies 2 (1-8), 79% were refractory to immediate prior therapy. 10 pts had prior ibrutinib of which 9 were ibrutinib refractory. 64% of pts had at least 1 high risk genetic feature (del17p, del11q, TP53 mut, NOTCH1 mut or complex karyotype). AE's (all causality) were manageable. Grade 3/4 AE's occurring in ≥ 3 pts included neutropenia (n=6, 43%), ALT/AST increase (n=3, 21%) and hypophosphatemia (n=3, 21%). One DLT occurred in a CLL pt at 200 mg dose level (ALT/AST elevation) which trigged expansion to 6 pts. No additional DLTs were reported, and no MTD was achieved. No increase in expected grade ≥ 3 PI3Kδ-associated toxicities were noted (1 pneumonitis event, no colitis events). ORR was 89% for CLL pts with ORR of 75% in BTK refractory CLL pts (3/4). Notably 2/4 BTK refractory CLL pts achieved a response to UMB + UTX (U2) induction alone prior to the addition of pembro. 4/5 RT pts were eligible for efficacy evaluation with 50% ORR (2/4, CR). The 2 RT CRs were durable and are ongoing (15+ mos and 7+ mos); both pts were ibrutinib refractory and had 7 (including SCT) and 8 prior lines respectively, and one had failed CAR-T. With a med follow up of 15 mos, 10/14 (71%) remain progression free (range 3 - 44 mos, Fig 1), including one CLL pt who completed consolidation and has been off therapy for 27+ mos. Sequential sampling for correlative studies demonstrated modest changes in Tregs numbers (Fig 2). Conclusion: The triplet combination of umbralisib + ublituximab + pembro was well-tolerated. Responses were durable in BTK refractory, high risk pts, including two CR's in RT pts. In contrast to pembro monotherapy, data suggest that CLL/RT pts who achieve ≥ PR with this checkpoint inhibitor-containing regimen can achieve durable responses. Correlative studies suggest that maintenance of Tregs may limit autoimmune sequelae. Enrollment is ongoing in both the CLL (BTK refractory only) and RT cohorts. Disclosures Mato: AbbVie: Consultancy, Research Funding; Portola: Research Funding; Regeneron: Research Funding; AstraZeneca: Consultancy; Johnson & Johnson: Consultancy; Celgene: Consultancy; Medscape: Honoraria; TG Therapeutics: Consultancy, Research Funding; Pharmacyclics, an AbbVie Company: Consultancy, Research Funding; Acerta: Research Funding; Prime Oncology: Honoraria. Svoboda:Regeneron: Research Funding; KITE: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Consultancy, Research Funding; Kyowa: Consultancy; Seattle Genetics: Consultancy, Research Funding; Merck: Research Funding. Schuster:Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Nordic Nanovector: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Honoraria, Research Funding; Dava Oncology: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Honoraria, Research Funding. Becker:GlycoMimetics: Research Funding. Brander:DTRM: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; BeiGene: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; Novartis: Consultancy, Other: DSMB; Pharmacyclics, an AbbVie Company: Consultancy, Honoraria, Research Funding; Acerta: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; TG Therapeutics: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; Teva: Consultancy, Honoraria; Genentech: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; AbbVie: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding. Dwivedy Nasta:Aileron: Research Funding; Pharmacyclics: Research Funding; Debiopharm: Research Funding; Incyte: Research Funding; Rafael/WF: Research Funding; Roche: Research Funding; Takeda/Millenium: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Merck: Other: DSMC. Landsburg:Takeda: Consultancy; Curis: Consultancy, Research Funding. Kennard:AbbVie, Gilead, Verastem: Consultancy. Zelenetz:Abbvie: Research Funding; Celgene: Consultancy; AstraZeneca: Consultancy; Novartis/Sandoz: Consultancy; Amgen: Consultancy; Gilead: Consultancy, Research Funding; Genentech/Roche: Consultancy, Research Funding. Purdom:TG Therapeutics: Employment, Equity Ownership. Paskalis:TG Therapeutics: Employment, Equity Ownership. Sportelli:TG Therapeutics: Employment, Equity Ownership. Miskin:TG Therapeutics: Employment, Equity Ownership. Weiss:TG Therapeutics: Employment, Equity Ownership. Shadman:Gilead Sciences: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy; Beigene: Research Funding; AbbVie: Consultancy; Genentech: Research Funding; Qilu Puget Sound Biotherapeutics: Consultancy; Genentech: Consultancy; Mustang Biopharma: Research Funding; Acerta Pharma: Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding; Verastem: Consultancy.

Because of the importance of the phosphoinositide 3-kinase (PI3K)/AKT pathway in chronic lymphocytic leukemia (CLL), we evaluated in vitro cytotoxicity induced by perifosine, an AKT inhibitor, in CLL lymphocytes and found that the mean 50% effective dose (ED50) was 313 nM. We then performed a phase II trial of perifosine in patients with relapsed/refractory CLL to assess response, outcomes, toxicity and ex vivo correlative measures. After 3 months of treatment, six of eight patients showed stable disease, one achieved a partial response and one had progressive disease. Median event-free survival and overall survival in all patients treated were 3.9 and 9.7 months. Adverse events included hematologic, infectious/fever, pain, gastrointestinal and constitutional toxicities. Unexpectedly, AKT phosphorylation in CLL lymphocytes from treated patients was not correlated with response. Additionally, perifosine did not inhibit AKT phosphorylation in cultured CLL lymphocytes. Perifosine is cytotoxic to CLL cells in vitro, and largely induces stabilized disease in vivo, with an AKT-independent mechanism.

Summary Ibrutinib is effective in patients with chronic lymphocytic leukaemia (CLL); however, treatment resistance remains a problem. Ublituximab is a novel, glycoengineered anti-CD20 monoclonal antibody with single-agent activity in relapsed CLL. We report the results of a phase 2 study evaluating combination therapy with ibrutinib and ublituximab in patients with relapsed or refractory CLL. Patients received ibrutinib 420 mg once daily. Ublituximab was administered on days 1, 8 and 15 of cycle 1 followed by day 1 of cycles 2–6. Response assessments were completed at cycles 3 and 6; patients then continued on ibrutinib monotherapy per standard of care. Forty-one of 45 enrolled patients were evaluable for efficacy. Safety was consistent with prior experience for each drug, with infusion reactions the most prevalent adverse event. Combination therapy resulted in an overall response rate (ORR) of 88% at 6 months. In the 20 patients with high-risk features (17p or 11q deletions or TP53 mutation) and evaluable for efficacy, the ORR was 95%, with three patients (15%) achieving negative minimal residual disease. Median time to response was 8 weeks. Ublituximab in combination with ibrutinib resulted in rapid and high response rates. The long-term clinical benefit of ublituximab will be defined by an ongoing phase 3 trial (NCT 02301156).

BACKGROUND: The clinical activity of allosteric inhibitors of mammalian target of rapamycin (mTOR) inhibitors in renal cell carcinoma (RCC) may be limited by upstream activation of phosphatidylinositol 3 (PI3)-kinase/Akt resulting from mTOR1 inhibition. On the basis of this rationale, 2 independent phase 2 trials (Perifosine 228 and 231) were conducted to assess the efficacy and safety of the novel Akt inhibitor perifosine in patients with advanced RCC who had failed on previous vascular endothelial growth factor (VEGF)-targeted therapy. METHODS: In the Perifosine 228 trial, 24 patients with advanced RCC received oral perifosine (100 mg daily). Perifosine 231 enrolled 2 groups that received daily oral perifosine (100 mg daily): Group A comprised 32 patients who had received no prior mTOR inhibitor, and Group B comprised 18 patients who had received 1 prior mTOR inhibitor. RESULTS: In the Perifosine 228 trial, 1 patient achieved a partial response (objective response rate, 4%; 95% confidence interval, 0.7%-20%), and 11 patients (46%) had stable disease as their best response. The median progression-free survival was 14.2 weeks (95% confidence interval, 7.7-21.6 weeks). In the Perifosine 231 trial, 5 patients achieved a partial response (objective response rate, 10%; 95% confidence interval, 4.5%-22.2%) and 16 patients (32%) had stable disease as their best response. The median progression-free survival was 14 weeks (95% confidence interval, 12.9, 20.7 weeks). Overall, perifosine was well tolerated, and there were very few grade 3 and 4 events. The most common toxicities included nausea, diarrhea, musculoskeletal pain, and fatigue. CONCLUSIONS: Although perifosine demonstrated activity in patients with advanced RCC after failure on VEGF-targeted therapy, its activity was not superior to currently available second-line agents. Nonetheless, perifosine may be worthy of further study in RCC in combination with other currently available therapies. Cancer 2012. © 2012 American Cancer Society.

edu † Previous presentations are given in Appendix I. Summary The combination of lenalidomide–dexamethasone is active in multiple myeloma (MM). Preclinical data showed that the Akt inhibitor, perifosine, sensitized MM cells to lenalidomide and dexamethasone, providing the rationale for this Phase I, multicentre, single-arm study to assess the safety and determine the maximum-tolerated dose (MTD) of perifosine–lenalidomide–dexamethasone in relapsed and relapsed/refractory MM. Patients received escalating doses of perifosine 50–100 mg daily and lenalidomide 15–25 mg once daily on days 1–21 of each 28-d cycle, plus dexamethasone 20–40 mg weekly thereafter, as indicated. Thirty-two patients were enrolled across four dose cohorts. MTD was not reached, with 31 patients evaluable for safety/tolerability. The most common all-causality grade 1-2 adverse events were fatigue (48%) and diarrhoea (45%), and grade 3–4 neutropenia (26%), hypophosphataemia (23%), thrombocytopenia (16%), and leucopenia (13%). Among 30 evaluable patients, 73% (95% confidence interval, 57·5–89·2%) achieved a minimal response or better, including 50% with a partial response or better. Median progression-free survival was 10·8 months and median overall survival 30·6 months. Response was associated with phospho-Akt in pharmacodynamic studies. Perifosine–lenalidomide–dexamethasone was well tolerated and demonstrated encouraging clinical activity in relapsed and relapsed/refractory MM.

7504 Background: Patients (pts) with high-risk chronic lymphocytic leukemia (CLL) defined by interruptions in TP53 (either by mutation or deletion) or loss of chromosome 11q experience inferior outcomes with ibrutinib (IB) monotherapy (O’Brien ASH 2016). Ublituximab (UTX) is a novel glycoengineered mAb with enhanced ADCC targeting a unique epitope on the CD20 antigen. GENUINE is the first randomized Ph 3 trial conducted assessing the addition of a novel agent to ibrutinib in high-risk rel/ref CLL, and evaluates IB monotherapy vs. UTX + IB. Methods: Eligible pts with rel/ref CLL and centrally confirmed del17p, del11q, and/or a TP53 mutation were randomized 1:1 to receive IB (420 mg QD) alone or with UTX (900 mg on D1, 8, 15 of Cycle 1, D1 of Cycle 2-6, and Q3 Cycles thereafter). There was no limit on number of prior therapies. Prior IB exposure was excluded. The primary endpoint was overall response rate (ORR) per iwCLL 2008 criteria, with secondary endpoints including CR rate, MRD negativity, PFS, time to response (TTR) and safety. Results: 126 pts were randomized at sites in the US and Israel, with 117 pts treated (59 on UTX + IB, 58 on IB alone). Median age 67, median 3 prior therapies (range 1-8), > 70% of were male. High-risk cytogenetics were relatively balanced with ~ 50% of pts having del17p. UTX+IB was well tolerated, with infusion reactions the most prevalent AE (44%, GR3/4 5%). Neutropenia was comparable with the combination (17%, Gr3/4 7% vs. 10%, Gr3/4 9%), and other AE’s were similar or lower with UTX+IB vs. IB alone (all grades), including fatigue (17% vs. 31%), dizziness (12% vs. 21%), contusion (12% vs. 26%), anemia (10% vs. 16%), and myalgia (9% vs. 14%). At median follow-up of 12 mo, best ORR per independent central review was 80% for UTX + IB vs. 47% for IB alone (p < 0.001). While not powered for secondary endpoints, observed advantages were seen in PFS and radiographic CR rate in the UTX + IB arm. CR and MRD confirmation is ongoing. Median TTR for the combo was 1.97 mo vs. 3.8 mo for IB alone. Both arms have responses pending confirmatory assessments. Conclusions: The addition of UTX to IB demonstrated a superior response rate compared to IB alone without additional clinically significant toxicity. Clinical trial information: NCT02301156.

Purpose In a multicenter, double-blind phase II trial, we compared the efficacy and safety of perifosine plus capecitabine (P-CAP) with placebo plus capecitabine (CAP) in patients with metastatic colorectal cancer (mCRC) who had progressed after as many as two prior therapies. Patients and Methods Patients (n = 38) not previously treated with capecitabine received P-CAP (perifosine 50 mg orally once daily, days 1 to 21 and CAP 825 mg/m2 orally twice daily, days 1 to 14) or CAP (825 mg/m2 orally twice daily, days 1 to 14) in 21-day cycles until disease progression. The primary end point was time to progression (TTP). Secondary end points included overall survival (OS), overall response rate (ORR), safety, and tolerability. Results Twenty patients were randomly assigned to P-CAP and 18 to CAP. Median TTP (27.5 v 10.1 weeks; P < .001) and median OS (17.7 v 7.6 months; P = .0052) were improved in patients receiving P-CAP versus CAP. ORR was 20% v 7% in the P-CAP and CAP groups, respectively, and one patient in the P-CAP group had a complete response. A subset analysis of fluorouracil-refractory patients showed a median TTP of 17.6 v 9.0 weeks (P < .001) and median OS of 15.1 v 6.5 months (P = .0061). Toxicities, including diarrhea, nausea, fatigue, and hand-foot syndrome, were manageable. Conclusion P-CAP showed promising clinical activity compared with CAP in previously treated patients with mCRC. A phase III trial is underway comparing P-CAP with CAP in patients with refractory mCRC.

Purpose Novel agents have improved patient outcome in relapsed or relapsed/refractory multiple myeloma (MM). Preclinical data show that the novel signal transduction modulator, perifosine, enhances the cytotoxicity of dexamethasone and bortezomib. Clinical data suggest that perifosine in combination with dexamethasone has activity in relapsed or relapsed/refractory MM. Patients and Methods In a phase I/II study, perifosine in combination with bortezomib with or without dexamethasone was prospectively evaluated in 84 patients with relapsed or relapsed/refractory MM. All were heavily pretreated and bortezomib exposed; 73% were refractory to bortezomib, and 51% were refractory to bortezomib and dexamethasone. The dose selected for the phase II study was perifosine 50 mg/d plus bortezomib 1.3 mg/m2, with the addition of low-dose dexamethasone at 20 mg if progression occurred on perifosine plus bortezomib alone. Results An overall response rate (ORR; defined as minimal response or better) of 41% was demonstrated with this combination in 73 evaluable patients, including an ORR of 65% in bortezomib-relapsed patients and 32% in bortezomib-refractory patients. Therapy was generally well tolerated; toxicities, including gastrointestinal adverse effects and fatigue, proved manageable. No treatment-related mortality was seen. Median progression-free survival was 6.4 months, with a median overall survival of 25 months (22.5 months in bortezomib-refractory patients). Conclusion Perifosine–bortezomib ± dexamethasone demonstrated encouraging activity in heavily pretreated bortezomib-exposed patients with advanced MM. A phase III trial is underway comparing perifosine–bortezomib plus dexamethasone with bortezomib–dexamethasone in patients with relapsed/refractory MM previously treated with bortezomib.

BET (bromodomain and extra-terminal) proteins bind to acetylated lysine residues on chromatin and participate in the regulation of gene transcription. Inhibition of BET protein binding to chromatin with small molecules selectively suppresses the transcription of a set of oncogenes, including MYC and BCL-2. TG-1601 is a novel, selective and potent small molecule inhibitor of BET bromodomains. TG-1601 binds to the first and second bromodomains (BD1, BD2) of the BET protein family, BRD2, BRD3, BRD4, and BRDT, with Kd values ranging from 0.5 nM to 9.1 nM. MYC protein expression is strongly inhibited in the MV4-11 cancer cell line with an EC50 of 5 nM, with GI50 comprised between 15 nM and 85 nM in a variety of leukemia and myeloma cancer cell lines, indicating potent inhibition of cell proliferation. Time course and dose-response studies conducted in mice bearing subcutaneous MV4-11 xenografts showed that MYC protein was undetectable 3 hours following a single 25 mg/kg oral dose, with a TG-1601 tumor concentration of 6uM achieved. Interestingly, at 24h post-dose, while TG-1601 is cleared from the tumor, MYC protein level remains below 40% of its initial level, indicating a long-lasting effect pharmacodynamic of TG-1601, potentially attributable to enhanced binding affinity compared to earlier generation molecules. In agreement with this long-lasting effect, efficacy studies in MV4-11 tumor-bearing mice, dosed with a 20 mg/kg/day PO regimen interrupted by increasing drug holiday periods, showed that drug holidays of 2, 3 and 4 days per week only modestly affected efficacy (3%, 15% and 12% TGI respectively), suggesting discontinuous dosing of TG-1601 in clinic may not significantly impact efficacy. Anti-cancer agents have been shown - in vitro or in vivo - to synergize with BET inhibitors. Here we show that TG-1601 and anti PD-1 antibody demonstrated synergistic anti-tumor activity when combined in the B16F10 model, an aggressive syngeneic model of melanoma. TG-1601 inhibition of MYC, CCR-2 and IL1RN gene expression was tested in a whole blood ex-vivo experiment, and the genes were validated as pharmacodynamic markers to monitor TG-1601 activity in clinic. In conclusion, TG-1601 is a novel BET inhibitor with remarkably strong affinity and a potent ability to inhibit MYC expression and cell growth, with favorable pharmacokinetic properties supporting clinical development. Its properties in vivo provide an opportunity for the rational development of TG-1601 as an anti-cancer agent, taken alone or in combination with other small molecules or antibodies. IND enabling studies are underway, with clinical evaluation expected to commence in the first half of 2018. Citation Format: Emmanuel Normant, Leonid Gorelik, Rama Shmeis, Henry Le, Robert Nisch, Karen TenHuisen, Teja Turpuseema, James Oliviero, Hari P. Miskin, Peter Sportelli, Michael S. Weiss. TG-1601 is a novel BET inhibitor with strong binding affinity and long-lasting effect in pre-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5790.

7530Background: Although KI therapies are generally well-tolerated, intolerance is the most common reason for discontinuation, thus representing an unmet medical need. Umbralisib (TGR-1202), a next...