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Purpose: This global phase I trial investigated the safety, efficacy, pharmacokinetics, and pharmacodynamics of lisaftoclax (APG-2575), a novel, orally active, potent selective B-cell lymphoma 2 (BCL-2) inhibitor, in patients with relapsed or refractory chronic lymphocytic leukemia or small lymphocytic lymphoma (R/R CLL/SLL) and other hematologic malignancies (HMs). Patients and Methods: Maximum tolerated dose (MTD) and recommended phase II dose were evaluated. Outcome measures were safety and tolerability (primary) and pharmacokinetic variables and antitumor effects (secondary). Pharmacodynamics in patient tumor cells were explored. Results: Among 52 patients receiving lisaftoclax, MTD was not reached. Treatment-emergent adverse events (TEAEs) included diarrhea (48.1%), fatigue (34.6%), nausea (30.8%), anemia and thrombocytopenia (28.8% each), neutropenia (26.9%), constipation (25.0%), vomiting (23.1%), headache (21.2%), peripheral edema and hypokalemia (17.3% each), and arthralgia (15.4%). Grade ≥ 3 hematologic TEAEs included neutropenia (21.2%), thrombocytopenia (13.5%), and anemia (9.6%), none resulting in treatment discontinuation. Clinical pharmacokinetic and pharmacodynamic results demonstrated that lisaftoclax had a limited plasma residence and systemic exposure and elicited rapid clearance of malignant cells. With a median treatment of 15 (range, 6–43) cycles, 14 of 22 efficacy-evaluable patients with R/R CLL/SLL experienced partial responses, for an objective response rate of 63.6% and median time to response of 2 (range, 2–8) cycles. Conclusions: Lisaftoclax was well tolerated, with no evidence of tumor lysis syndrome. Dose-limiting toxicity was not reached at the highest dose level. Lisaftoclax has a unique pharmacokinetic profile compatible with a potentially more convenient daily (vs. weekly) dose ramp-up schedule and induced rapid clinical responses in patients with CLL/SLL, warranting continued clinical investigation.

These are all the Supplementary Figures: S1, S2, S3, S4, S5, S6, and S7

Summary of BH3 profiling for PBMC samples collected at baseline.

Purpose:This global phase I trial investigated the safety, efficacy, pharmacokinetics, and pharmacodynamics of lisaftoclax (APG-2575), a novel, orally active, potent selective B-cell lymphoma 2 (BCL-2) inhibitor, in patients with relapsed or refractory chronic lymphocytic leukemia or small lymphocytic lymphoma (R/R CLL/SLL) and other hematologic malignancies (HMs).Patients and Methods:Maximum tolerated dose (MTD) and recommended phase II dose were evaluated. Outcome measures were safety and tolerability (primary) and pharmacokinetic variables and antitumor effects (secondary). Pharmacodynamics in patient tumor cells were explored.Results:Among 52 patients receiving lisaftoclax, MTD was not reached. Treatment-emergent adverse events (TEAEs) included diarrhea (48.1%), fatigue (34.6%), nausea (30.8%), anemia and thrombocytopenia (28.8% each), neutropenia (26.9%), constipation (25.0%), vomiting (23.1%), headache (21.2%), peripheral edema and hypokalemia (17.3% each), and arthralgia (15.4%). Grade ≥ 3 hematologic TEAEs included neutropenia (21.2%), thrombocytopenia (13.5%), and anemia (9.6%), none resulting in treatment discontinuation. Clinical pharmacokinetic and pharmacodynamic results demonstrated that lisaftoclax had a limited plasma residence and systemic exposure and elicited rapid clearance of malignant cells. With a median treatment of 15 (range, 6–43) cycles, 14 of 22 efficacy-evaluable patients with R/R CLL/SLL experienced partial responses, for an objective response rate of 63.6% and median time to response of 2 (range, 2–8) cycles.Conclusions:Lisaftoclax was well tolerated, with no evidence of tumor lysis syndrome. Dose-limiting toxicity was not reached at the highest dose level. Lisaftoclax has a unique pharmacokinetic profile compatible with a potentially more convenient daily (vs. weekly) dose ramp-up schedule and induced rapid clinical responses in patients with CLL/SLL, warranting continued clinical investigation.

Bruton tyrosine kinase inhibitors have indisputably transformed the treatment landscape of chronic lymphocytic leukemia, but require continuous therapy to maintain response. This places emphasis on their unique toxicity profile and potential loss of efficacy owing to resistance. Data from single-arm clinical studies are suggestive of comparable efficacy and favorable toxicity profiles of next-generation Bruton tyrosine kinase inhibitors. This is supported by the ASPEN study in Waldenstrom's macroglobulinemia, which convincingly demonstrated that zanubrutinib has a better toxicity profile than ibrutinib. Novel, reversible Bruton tyrosine kinase inhibitors are showing the potential to improve long-term efficacy by overcoming common mechanisms of resistance.

Intravenous high-dose methotrexate (HD-MTX) is a critical chemotherapeutic agent in hematological malignancies, however, data are lacking on how to predict and prevent toxicities such as kidney injury. We retrospectively analyzed 539 episodes of HD-MTX (≥1 g/m

Ibrutinib is a first-in-class, highly potent Bruton tyrosine kinase inhibitor which has become standard of care for patients with chronic lymphocytic leukaemia and other lymphoproliferative disorders. It requires indefinite administration which places emphasis on toxicity and long-term tolerance. Extensive use of ibrutinib in studies and clinical practice has better defined its full toxicity profile which has made its use more challenging than initially foreseen. In particular, dysrhythmias, bleeding, infections and constitutional symptoms have been reported and can result in dose reduction or discontinuation of ibrutinib. Herein, we review the common as well as rare but important toxicities and discuss approach and management on a practical level. We also highlight that patients should be regularly monitored for adverse events and proactively treated to minimise side effects and avoid disruption.

Massive obstetric haemorrhage (MOH) is a leading cause of maternal morbidity and mortality world-wide. Using the Australian and New Zealand Massive Transfusion Registry, we performed a bi-national cohort study of MOH defined as bleeding at ≥20 weeks' gestation or postpartum requiring ≥5 red blood cells (RBC) units within 4 h. Between 2008 and 2015, we identified 249 cases of MOH cases from 19 sites. Predominant causes of MOH were uterine atony (22%), placenta praevia (20%) and obstetric trauma (19%). Intensive care unit admission and/or hysterectomy occurred in 44% and 29% of cases, respectively. There were three deaths. Hypofibrinogenaemia (

Bruton tyrosine kinase inhibitors have indisputably transformed the treatment landscape of chronic lymphocytic leukemia, but require continuous therapy to maintain response. This places emphasis on their unique toxicity profile and potential loss of efficacy owing to resistance. Data from single-arm clinical studies are suggestive of comparable efficacy and favorable toxicity profiles of next-generation Bruton tyrosine kinase inhibitors. This is supported by the ASPEN study in Waldenstrom's macroglobulinemia, which convincingly demonstrated that zanubrutinib has a better toxicity profile than ibrutinib. Novel, reversible Bruton tyrosine kinase inhibitors are showing the potential to improve long-term efficacy by overcoming common mechanisms of resistance.

Venetoclax is a highly selective and effective B-cell lymphoma-2 (BCL-2) inhibitor, which is able to reinstate the apoptotic potential of cancer cells. With its full repertoire yet to be explored, it has changed the therapeutic landscape in haematological malignancies, and most particularly chronic lymphocytic leukaemia (CLL), acute myeloid leukaemia (AML) and multiple myeloma (MM). In CLL, it has shown remarkable efficacy both as monotherapy and in combination therapy. Based on data from MURANO and CLL14 studies, fixed-duration combination therapy of venetoclax with anti-CD20 antibody is now the standard of care in numerous countries. In AML, although of limited efficacy as a single agent, venetoclax combination therapy has demonstrated encouraging outcomes including rapid, durable responses and acceptable toxicity, particularly in the older, unfit patient population. Multiple myeloma with translocation (t)(11;14) harbours high BCL-2/ myeloid cell leukaemia sequence-1 (MCL-1) and BCL-2/BCL-XL ratio and is, therefore, particularly suited for venetoclax-based therapy. Despite a wide ranging and evolving clinical role in these diseases, venetoclax treatment is not curative and, over time, clonal evolution and disease relapse appear to be the norm. While a variety of distinct resistance mechanisms have been identified, frequently emerging in a sub-clonal pattern, the full picture is yet to be characterised. Further illumination of the complex interplay of various factors is needed to pave the way for rational combination therapies aimed at circumventing resistance and improving durability of disease control. Serial molecular studies can aid in identification of new prognostically significant and/or targetable mutations.

Background: BCL2, a key regulator of apoptosis, is aberrantly expressed in many hematologic malignancies, which can lead to pathologic cancer cell survival. BCL2 inhibitors have been shown to be safe and effective, resulting in their approval for the treatment of pts with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and acute myeloid leukemia. Treatment with the currently approved BCL2 inhibitor, venetoclax, can be limited by common gastrointestinal toxicities, neutropenia, and the emergence of specific BCL2 mutations around the BH3-binding groove causing resistance. BGB-11417 was developed as a potent and highly selective inhibitor of BCL2. It has shown antitumor activity superior to venetoclax in human acute lymphoblastic leukemia, mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma (DLBCL) xenograft models (Hu, AACR 3077). BGB-11417 also has a favorable pharmacokinetic profile with excellent bioavailability and selectivity for BCL2 at concentration The combination of a BCL2 inhibitor and a BTK inhibitor is tolerable with synergistic activity in CLL and MCL pts (Hillmen, J Clin Oncol 2019;37(30):2722-9; Jain, N Engl J Med 2019;30;380(22):2095-103; Siddiqi, ASH 2020 S158; Tam, N Engl J Med 2018; 378:1211-23). Zanubrutinib is a next-generation BTK inhibitor that has shown excellent activity and favorable toxicity in pts with CLL/SLL (Hillmen, EHA 2021 LB1900) and MCL (Tam, Blood Adv 2021;5(12):2577-85); with approval for treatment in MCL. Here we report preliminary results of the BGB-11417-101 trial (NCT04277637) in pts with non-Hodgkin lymphoma (NHL) or CLL/SLL treated with BGB-11417 monotherapy or in combination with zanubrutinib. Methods: BGB-11417-101 is a phase 1, open label, multicenter, dose-escalation and expansion study. Pts with NHL or CLL/SLL are treated with BGB-11417 as monotherapy or in combination with zanubrutinib. For dose escalation, pts with R/R B-cell malignancies are enrolled in 1 of 5 potential dose levels of BGB-11417 (40, 80, 160, 320, or 640 mg once daily). All pts utilize a ramp-up to intended target dose that varies by disease type. Pts in the combination therapy arm receive zanubrutinib 320 mg daily beginning 8-12 weeks before BGB-11417 is introduced. Adverse events (AEs) are reported per Common Terminology Criteria for AEs v5.0. Dose-limiting toxicity (DLT; assessed from ramp-up through day 21 at intended daily dose), evaluated by Bayesian logistic regression model, will be used to determine the maximum tolerated dose (MTD). Results: As of 24 May 2021 (data cutoff) 19 pts had been treated; 14 pts with monotherapy (NHL: n=11; CLL/SLL: n=3) and 5 pts with combination (all CLL; 3 pts were still on zanubrutinib pretreatment; 2 had started combination treatment). Median age was 72 y (range, 50-86); median follow-up was 1.9 mo (range, 0.7-12.4); all pts were R/R with a median of 2 prior regimens (range, 1-4). No DLTs were observed in pts with NHL receiving BGB-11417 monotherapy (n=11) up to the 160 mg dose level. AEs across all dose levels occurring in ≥2 pts (monotherapy) or ≥1 pt (combination) are listed in Table 1. A total of 5 pts discontinued treatment (all NHL) due to disease progression (n=4; 2 at 40 mg, 2 at 80 mg) or lack of efficacy (n=1 at 40 mg). No pt discontinued due to AEs. Laboratory tumor lysis syndrome was observed in 1 pt with CLL and high tumor burden (resolved with no sequelae). Initial efficacy after 3-month restaging in pts with CLL/SLL demonstrated 1 partial response (monotherapy arm) at the first dose level tested. All pts with CLL/SLL who have completed ramp-up (n=2, both monotherapy) normalized absolute lymphocyte count (ALC). Marked decreases in ALC were observed in pts with CLL at doses as low as 1 mg (Figure 1). Conclusion: Preliminary results suggest that BGB-11417 monotherapy is tolerable in pts with R/R NHL at the tested dose levels. Further assessment of safety and efficacy of BGB-11417 +/- zanubrutinib in CLL/SLL and NHL will be presented at the meeting, and evaluation in patients with treatment naïve CLL/SLL, R/R MCL, and R/R WM is planned. Figure 1 Figure 1. Disclosures Tam: AbbVie: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Loxo: Consultancy; Novartis: Honoraria; Pharmacyclics: Honoraria. Verner: Janssen-Cilag Pty Ltd: Research Funding. Lasica: Celgene: Other: Travel, Accommodations, Expenses; Janssen: Other: Education. Arbelaez: Amgen: Other: Travel, Accommodations, Expenses. Browett: AbbVie: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees. Soumerai: BeiGene: Consultancy, Research Funding; AstraZeneca: Consultancy; Adaptive Biotechnologies: Consultancy, Research Funding; AbbVie: Consultancy; GlaxoSmithKline: Research Funding; BostonGene: Research Funding; BMS: Consultancy; Seattle Genetics: Consultancy; TG Therapeutics: Consultancy, Research Funding. Hilger: BeiGene: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Fang: BeiGene (Shanghai) Co, Ltd.: Current Employment, Current equity holder in publicly-traded company. Huang: BeiGene: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company, Divested equity in a private or publicly-traded company in the past 24 months, Other: Travel, Accommodations, Expenses; Protara Therapeutics: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Simpson: Janssen: Research Funding; GSK: Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; MSD: Research Funding; Roche: Research Funding; Celgene: Research Funding; Amgen: Research Funding; AbbVie: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; BeiGene: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Opat: Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GIlead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics LLC, an AbbVie Company: Research Funding; Monash Health: Current Employment; BeiGene: Research Funding; Sandoz: Research Funding. Cheah: Ascentage Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Lilly: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; TG therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Beigene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Zanubrutinib is an investigational agent and has not been approved for NHL or CLL/SLL in the US

Introduction: TG-1701 is an irreversible, selective, novel Bruton's tyrosine kinase inhibitor (BTKi) administered once daily (QD). BTK inhibitors, as well as the U2 combination (anti-CD20 mAb ublituximab + the PI3Kδ-CK1ε inhibitor umbralisib), are highly efficacious in chronic lymphocytic leukemia (CLL), each of which have been previously demonstrated to be superior over standard chemoimmunotherapy. Treatment with a more selective BTK inhibitor could result in improved efficacy and safety outcomes compared with ibrutinib (ALPINE study, EHA 2021), and we hypothesized that dual blockade of the B-cell receptor (BCR) pathway through combination of TG-1701 with U2 may confer greater depth of response compared to either regimen alone. Methods: Patients with CLL and non-Hodgkin lymphoma (NHL) were enrolled in an ongoing Phase 1 study. After characterizing the safety profile of TG-1701 monotherapy, a parallel dose escalation arm of TG-1701+U2 was implemented. Select dose levels of TG-1701 monotherapy and TG-1701+U2 were also expanded. All patients were treated until disease progression, unacceptable toxicity, or investigator/patient decision to withdraw. Safety was evaluated in all treated patients, and efficacy was evaluated in all treated patients who had at least 1 post-baseline assessment. TG-1701 monotherapy data were previously presented; herein we present data from the TG-1701+U2 dose escalation/expansion and the TG-1701 monotherapy CLL expansion cohorts Results: As of July 2021, 142 patients were treated with TG-1701, 36 of whom were enrolled in the TG-1701+U2 arm. The median # of prior therapies across all treated patients was 1 (range, 0-10) and all patients were BTKi-naïve. Among the 36 patients treated with U2+1701, 19 were evaluable for efficacy and safety (17 too early to evaluate). The median age was 69 years (range 47-81), and 56% were male. TG-1701+U2 was well tolerated at 4 different dose levels without dose-limiting toxicities. The most common (>30%) all-causality, all grade treatment-emergent adverse events (TEAEs) were diarrhea (53%) contusion (42%), nausea (37%), hypertension, ALT/AST increase, and fatigue (all 32% each) with TG-1701+U2. Grade 3/4 AEs >15% were limited to ALT/AST increase (21%). Dose reduction occurred in 1 patient due to an AE, and 4 patients discontinued at least 1 study drug due to an AE: 2 discontinued umbralisib, 1 discontinued umbralisib and TG-1701, and 1 discontinued all 3 agents. At the data cut-off, overall response rate (ORR) was 84% (4 CR and 12 PR) among 19 evaluable patients, with remaining patients awaiting post-baseline assessment. In the monotherapy CLL-specific cohorts (200 mg QD, n=20; and 300 mg QD, n=20), 40 pts were evaluable for safety, and 39 for efficacy (1 pt withdrew due to COVID prior to first response assessment). The median age was 71 (range 49-86), and 43% were male. The most common TEAEs were increased ALT/AST (all grades: 18%; grade ≥3: 3%), followed by diarrhea (all grades: 15%; grade ≥3: none), and neutropenia (all grades: 13%; grades ≥3: 13%). There were no cases of atrial fibrillation, major bleeding, or ventricular tachyarrhythmia in the CLL cohorts at a median follow-up of 12.8 months (range 2.5 - 20.8). TEAEs leading to TG-1701 dose reduction occurred in 1 (3%) patient. No patients in the 200 mg or 300 mg CLL cohorts have discontinued due to AEs. In patients with anemia and thrombocytopenia at baseline, sustained improvement in hematologic variables was observed. The ORR among 39 patients was 97% (all PR/PR-L). Lymphocytosis resolved to normal value or The median duration of response has not been reached in either cohort. Best change in tumor burden from baseline in patients with CLL is presented in Figure 1. Conclusions: TG-1701 exhibits an encouraging safety and efficacy profile as monotherapy in patients with CLL and additionally shows promising activity and a manageable tolerability profile in combination with U2. Future registration trials are being planned in CLL with TG-1701. Recruitment to this study (NCT03671590) continues. Figure 1 Figure 1. Disclosures Cheah: MSD: Consultancy, Honoraria, Other: advisory, Research Funding; TG Therapeutics: Consultancy, Honoraria, Other: advisory; Loxo/Lilly: Consultancy, Honoraria, Other: advisory; AstraZeneca: Consultancy, Honoraria, Other: advisory; Celgene: Research Funding; AbbVie: Research Funding; Ascentage pharma: Consultancy, Honoraria, Other: advisory; Beigene: Consultancy, Honoraria, Other: advisory; Roche: Consultancy, Honoraria, Other: advisory and travel expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: advisory; Gilead: Consultancy, Honoraria, Other: advisory. 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. Lasica: Abbvie: Speakers Bureau; Celgene: Other: Ambassadorship. Wróbel: 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. Walewski: roche: Honoraria, Research Funding, Speakers Bureau; GSK: Research Funding; novartis: Honoraria, Research Funding; takeda: Consultancy, Honoraria; abbvie: Consultancy, Honoraria; gilead: Consultancy, Honoraria; amgen: Consultancy, Honoraria; seervier: Consultancy, Honoraria. Giannopoulos: Sanofi-Genzyme: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Sandoz: Consultancy, Honoraria; TG Therapeutics: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria, Research Funding; Pfizer: Honoraria; Gilead: Honoraria, Research Funding; Bei-Gene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Teva: Honoraria; Roche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Polish Myeloma Consortium, Next Generation Hematology Association: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Honoraria, Research Funding. Lewis: AstraZeneca: Consultancy, Honoraria; Janssen: Honoraria, Patents & Royalties; Novartis: Patents & Royalties; Roche: Consultancy, Honoraria. 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. Miskin: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Ricart: TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Pfizer: Current equity holder in publicly-traded company; Merck: Current equity holder in publicly-traded company; Seagen: Current equity holder in publicly-traded company; Gilead: Current equity holder in publicly-traded company. O'Connor: Mundipharma: Consultancy; Kymera: Consultancy, Current equity holder in publicly-traded company; TG Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Nomocan: Consultancy; 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. Tam: BeiGene: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Loxo: Consultancy; Roche: Consultancy, Honoraria; Novartis: Honoraria; Pharmacyclics: Honoraria.

7525 Background: TG-1701 is a selective, covalent BTK inhibitor administered once daily (QD). Both the “U2” combination (anti-CD20 mAb ublituximab + the PI3Kδ-CK1ε inhibitor umbralisib) and BTK inhibition are highly active in treatment-naïve (TN) and relapsed/refractory (R/R) CLL, each having previously demonstrated superiority over standard chemoimmunotherapy. Here we report the results of the dose escalation of TG-1701 monotherapy and TG-1701+U2. Methods: Pts with R/R CLL and lymphoma were enrolled in a Ph 1 study initially evaluating dose escalation (DE) of oral TG-1701 QD continuously administered in 28-day cycles (100, 200, 300, and 400 mg). After characterizing the safety profile of TG-1701 monotherapy, we implemented a parallel DE arm of TG-1701+U2. Select dose levels of TG-1701 monotherapy were expanded in CLL, MCL and Waldenström's (WM). All pts were treated until disease progression. The primary objectives are to characterize the safety profile and define the recommended Ph 2 doses for the drugs alone and in combination. Results: As of 03 February 2021, 123 pts were treated with TG-1701: 25 in the monotherapy DE arm, 61 in the 200 mg disease-specific cohorts (20 CLL [5 TN], 21 MCL [4 TN], 20 WM [8 TN]), 20 in the 300 mg CLL cohort (4 TN), and 17 in the 1701+U2 DE arm. The median # of prior therapies was 1 (range, 1 - 10). All pts were BTKi-naïve. All 123 pts were evaluable for safety. TG-1701 was well tolerated and the maximum tolerated dose (MTD) for monotherapy was not reached at 400 mg (demonstrating near 100% saturation of the BTK at all dose levels studied). Treatment emergent adverse events (TEAE) of clinical interest included atrial fibrillation (AF 4.0% of pts, G ≥3 in 1 case), G ≥3 hypertension (2.4%), and bleeding events (18.7%, all G1-2). No cases of ventricular tachyarrhythmia were reported. TEAEs leading to TG-1701 dose reduction occurred in 6.5% of pts. TEAEs leading to treatment discontinuation occurred in 1.6% of pts (AF, COVID-19). At the data cut-off, 119 pts were evaluable for response, including 40 in DE (Table). The median duration of response has not been reached among responders overall. The median follow-up (mFU range) was 15.9 mos (1.3 - 28.6+) in DE and 8.5 mos (1.4 -15.6+) in disease-specific cohorts. Conclusions: TG-1701 exhibits an encouraging safety and efficacy profile. The combination of 1701+U2 has been well tolerated and dose escalation continues. The combination shows enhanced depth of response over TG-1701 monotherapy. Recruitment to this study continues. Response per investigator review by treatment group. Clinical trial information: NCT03671590. [Table: see text]

7502 Background: The BCL-2i venetoclax is active in certain HMs but can increase the risk of tumor lysis syndrome (TLS), requiring a 5-week dose ramp-up for CLL patients. Cases of severe neutropenia with venetoclax treatment have also been reported. Lisaftoclax is a novel, potent, selective BCL-2i that is active against HMs and is under clinical development. Methods: This first-in-human global phase I dose study assessed the safety, PK, PD, efficacy, and MTD/RP2D of lisaftoclax in patients with R/R CLL and other HMs. Lisaftoclax was orally administered daily in a 28-day cycle. Patients with CLL or intermediate-high TLS risk were initiated on a daily ramp-up schedule until the assigned dose before the study cycles. Results: On January 7, 2021, 35 pts had been enrolled and treated with lisaftoclax at doses ranging from 20 to 1,200 mg, with a median (range) of 2 (1-13) prior lines of treatment, and had diagnoses of R/R CLL or SLL (n = 15), MM (n = 6), FL (n = 5), WM (n = 4), and either AML, MCL, DLBCL, MDS, or HCL (n = 1 each). No DLT has been observed, even though 1,200 mg was considered as the highest dose treated. The MTD has not been reached, and no laboratory or clinical TLS has been reported. Any grade TRAEs in > 10% of pts included neutropenia (22.9%) and anemia (17.1%; hematologic), and fatigue (28.6%), diarrhea (17.1%), and nausea (11.4%; nonhematologic). Grade >3 TRAEs were neutropenia (14.3%) and thrombocytopenia, leukopenia, lymphopenia, fatigue, and nausea (2.9% of pts each). In CLL/SLL pts, grade 3-4 TRAEs included neutropenia (13.3%) and thrombocytopenia (6.7%), which did not cause treatment-related discontinuation. In all, 12 of 35 pts (34.3%) had non-treatment-related SAEs, and only two pts experienced > 1 SAE. With a median (range) treatment of 7 (3-20) cycles, 12 of 14 evaluable R/R CLL/SLL pts achieved PR, for an ORR of 85.7% and a median (range) time to response of 3 (2-7) cycles. Absolute lymphocyte counts (ALCs) were reduced at lisaftoclax doses as low as 20 mg/day. The preliminary PK profile showed that exposures increased with lisaftoclax doses from 20 to 1,200 mg (average half-life: 4-5 hours). On BH3 profiling, lisaftoclax rapidly triggered changes in BCL-2 complex in CLL/SLL pt samples, which were consistent with rapid clinical reductions in ALCs. Conclusions: Lisaftoclax was well tolerated up to 1,200 mg/day. No TLS was observed, even with the daily ramp-up schedule. There were no significant new or unmanageable safety findings, and the ORR in R/R CLL/SLL pts was 85.7%. Grade 3-4 TRAEs were infrequent, even at dose levels of 800 mg and above. BCL-2i lisaftoclax offers a treatment alternative for patients with R/R CLL/SLL and other HMs, with a daily ramp-up schedule that may be more pt “user friendly” and a favorable preliminary safety profile. Internal study identifier APG2575-001. Clinical trial information: NCT03537482.

TPS8055 Background: Len maintenance post ASCT is standard of care for patients (pts) with NDMM. Deep responses (CR or better) post ASCT correlates with better progression free survival (PFS). In a meta-analysis of len maintenance post ASCT (McCarthy PL et al. J Clin Oncol. 2017), only 10.7% of pts achieve CR post ASCT, and 72% of pts who discontinued len maintenance did so because of progressive disease (PD). Selinexor is a selective inhibitor of nuclear export that blocks exportin 1, thus retaining tumour suppressor proteins within the nucleus while blocking proto-oncoprotein translation. It is approved in combination with bortezomib and dexamethasone (dex) for pts with MM who have had at least 1 prior line of treatment, or with dex for pts with penta-refractory MM by the FDA. The oral bioavailability and weekly schedule of selinexor makes it suitable in combination with len for maintenance therapy. Given the encouraging activity (ORR 92%) and tolerability of selinexor, len and dex from the phase 1b/2 STOMP study, we hypothesise that combination low-dose selinexor and len (XR) will be well tolerated and effective, increasing CR and MRD negativity rate post ASCT, thus prolonging PFS compared to len. Methods: ALLG MM23 SeaLAND, is an ongoing randomised, multi-centre, phase 3 trial. Eligible pts ( > 17 years of age) have measurable disease, have undergone 3-6 cycles (C) of induction containing a proteasome inhibitor (PI) and/or immunomodulatory drug and recovered post melphalan-conditioned ASCT with adequate haematopoiesis, renal and liver function, and with ECOG performance status. Registration occurs prior to ASCT with screening between 75 to 115 days post ASCT. The study includes a lead-in safety phase of 20 patients with XR: Len 10mg daily days 1 to 21 and Selinexor 40mg weekly in a 28-day cycle. If well tolerated, Selinexor escalates to 60mg po weekly from C2 and Len to 15mg po daily from C4. Two safety reviews will occur after the 10th and 20th patients completes C2, respectively. Upon meeting safety criteria, a sample size of 290 pts will be randomised 1:1 to XR or lenalidomide (R). Therapy will continue until PD. The primary endpoint is PFS at 3 years post randomisation. Secondary endpoints include ORR and MRD-negativity rate (International Myeloma Working Group Response Criteria), PFS on next treatment line (PFS2), OS, safety and tolerability, quality of life, and cost effectiveness. Main analysis occurs after 232 patients complete 3-years of follow-up. Exploratory objective is to correlate immunological and molecular profiles to treatment response and resistance. ALLG MM23 SeaLAND is a multisite bi-national investigator-initiated trial lead by Australia and New Zealand’s national cooperative group, the Australasian Leukaemia & Lymphoma Group. Clinical trial registration: ACTRN12620000291987p. Clinical trial information: 12620000291987.

The management of CML in pregnancy is challenging with the need to balance disease control against potential teratogenic effects of TKI therapy. In this multi-center case-cohort study of 16 women in chronic phase, CML ceased TKI treatment pre- or post-conception during their first pregnancy. Thirteen patients were on imatinib; 9 ceased their TKI prior to conception and 7 ceased at pregnancy confirmation. Twelve patients had achieved either MMR or better at time of TKI cessation. Eleven women lost MMR during pregnancy and two patients lost CHR. Fourteen women reestablished MMR on TKI recommenced. The depth molecular response prior to conception appeared to correlate well with restoration of disease control on TKI recommencement though duration of MMR did not appear to be as important. While interruption of TKI treatment for pregnancy usually leads to loss of molecular response, loss of hematological response is uncommon and disease control is reestablished with resumption of therapy in the majority of women. Refereed/Peer-reviewed

There is currently minimal data on fertility outcomes in premenopausal women undergoing autologous stem cell transplant (ASCT) with carmustine, etoposide, cytarabine and melphalan (BEAM) conditioning. A retrospective analysis of fertility outcomes in premenopausal females aged between 18 and 40 yr who underwent BEAM/ASCT for lymphoma between 1995 and 2011 was performed at four transplant centres. Of 41 premenopausal women who underwent BEAM conditioning, 25 met the inclusion criteria with the main exclusion criterion being inadequate documentation. Eighteen had Hodgkin lymphoma, and seven had non-Hodgkin lymphoma. Median number of chemotherapy regimens pretransplant was 2 (1-3). Seventeen women (68%) with a median age at transplant of 25 yr (range 17-33) recovered their menses. The comparative group without recovery was older with a median age of 34 yr (range 20-40) (P = 0.007). Ten patients, with a median age at transplant of 22 yr (range 17-30), had 15 naturally conceived pregnancies. Chemotherapy regimens and lymphoma type did not obviously influence the incidence of menses recovery or conception. The incidence of recovery of menses and fertility in premenopausal women undergoing BEAM/ASCT for lymphoma is substantial. Younger age at transplant correlates with superior fertility outcomes.

We describe the first case of severe intravascular haemolysis secondary to IVIg treated with partial red cell exchange with Group O blood. A 62-year-old male was administered high dose IVIg (1.4g/kg in three divided doses) for a new diagnosis of chronic inflammatory demyelinating polyneuropathy. Within 24 hours of completing his IVIG infusion, he developed severe intravascular haemolysis, complicated by haemoglobuinuria and acute renal failure. Confirmatory tests included haemolysis screen, elution of anti-A and anti-B antibodies off the patient’s red cells and absence of other causes for haemolysis. The case illustrates patient risk factors for haemolytic IVIG reactions including: high IVIg dose >100g, non-O blood group (patient being AB RhD+) and discusses secretor status. Preventive measures including IVIg product processing are discussed. Although management of this condition is largely supportive, there may be a need to transfuse and group specific blood should be avoided. This patient received a single red cell exchange transfusion with Group O blood, with rapid resolution of renal impairment.