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In the phase 3 RESONATE study, ibrutinib demonstrated superior progression-free survival (PFS), overall survival (OS) and overall response rate (ORR) compared with ofatumumab in relapsed/refractory CLL patients with high-risk prognostic factors. We report updated results from RESONATE in these traditionally chemotherapy resistant high-risk genomic subgroups at a median follow-up of 19 months. Mutations were detected by Foundation One Heme Panel. Baseline mutations in the ibrutinib arm included TP53 (51%), SF3B1 (31%), NOTCH1 (28%), ATM (19%) and BIRC3 (14%). Median PFS was not reached, with 74% of patients randomized to ibrutinib alive and progression-free at 24 months. The improved efficacy of ibrutinib vs ofatumumab continues in all prognostic subgroups including del17p and del11q. No significant difference within the ibrutinib arm was observed for PFS across most genomic subtypes, although a subset carrying both TP53 mutation and del17p had reduced PFS compared with patients with neither abnormality. Reduced PFS or OS was not evident in patients with only del17p. PFS was significantly better for ibrutinib-treated patients in second-line vs later lines of therapy. The robust clinical activity of ibrutinib continues to show ongoing efficacy and acceptable safety consistent with prior reports, independent of various known high-risk mutations.

Abstract: First-generation Bruton tyrosine kinase (BTK) inhibitor, ibrutinib, has been associated with an increased risk of cardiovascular toxicities. Zanubrutinib is a more selective, next-generation BTK inhibitor. In this analysis, incidence rates of atrial fibrillation, symptomatic (grade ≥2) ventricular arrhythmia, and hypertension were evaluated in a pooled analysis of 10 clinical studies with zanubrutinib monotherapy in patients (N = 1550) with B-cell malignancies and a pooled analysis of head-to-head studies comparing zanubrutinib with ibrutinib (ASPEN cohort 1; ALPINE). Among the 10 studies, most patients (median age, 67 years) were male (66.3%) and had CLL/SLL (60.5%). Overall incidence and exposure-adjusted incidence rates (EAIR) for atrial fibrillation, symptomatic ventricular arrhythmia, and hypertension were lower with zanubrutinib than ibrutinib. Despite a similar prevalence of preexisting cardiovascular events in ASPEN and ALPINE, atrial fibrillation/flutter incidence rates (6.1% vs 15.6%) and EAIR (0.2 vs 0.64 persons per 100 person-months; P < .0001) were lower with zanubrutinib than with ibrutinib. Symptomatic ventricular arrhythmia incidence was low for both zanubrutinib (0.7%) and ibrutinib (1.7%) with numerically lower EAIR (0.02 vs 0.06 persons per 100 person-months, respectively) for zanubrutinib. The hypertension EAIR was lower with zanubrutinib than ibrutinib in ASPEN but similar between treatment arms in ALPINE. The higher hypertension EAIR in ALPINE was inconsistent with other zanubrutinib studies. However, fewer discontinuations (1 vs 14) and deaths (0 vs 6) due to cardiac disorders occurred with zanubrutinib versus ibrutinib in ALPINE. These data support zanubrutinib as a treatment option with improved cardiovascular tolerability compared with ibrutinib for patients with B-cell malignancies in need of BTK inhibitors. These trials were registered at www.ClinicalTrials.gov as # NCT03053440, NCT03336333, NCT03734016, NCT04170283, NCT03206918, NCT03206970, NCT03332173, NCT03846427, NCT02343120, and NCT03189524., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Abstract: High-count monoclonal B-cell lymphocytosis (HCMBL) is a precursor condition to chronic lymphocytic leukemia (CLL). We have shown that among individuals with HCMBL, the CLL-International Prognostic Index (CLL-IPI) is prognostic for time-to-first therapy (TTFT). Little is known about the prognostic impact of somatically mutated genes among individuals with HCMBL. We sequenced DNA from 371 individuals with HCMBL using a targeted sequencing panel of 59 recurrently mutated genes in CLL to identify high-impact mutations. We compared the sequencing results with that of our treatment-naïve CLL cohort (N = 855) and used Cox regression to estimate hazard ratios and 95% confidence intervals (CIs) for associations with TTFT. The frequencies of any mutated genes were lower in HCMBL (52%) than CLL (70%). At 10 years, 37% of individuals with HCMBL with any mutated gene had progressed requiring treatment compared with 10% among individuals with HCMBL with no mutations; this led to 5.4-fold shorter TTFT (95% CI, 2.6-11.0) among HCMBL with any mutated gene vs none, independent of CLL-IPI. When considering individuals with low risk of progression according to CLL-IPI, those with HCMBL with any mutations had 4.3-fold shorter TTFT (95% CI, 1.6-11.8) vs those with none. Finally, when considering both CLL-IPI and any mutated gene status, we observed individuals with HCMBL who were high risk for both prognostic factors had worse prognosis than patients with low-risk CLL (ie, 5-year progression rate of 32% vs 21%, respectively). Among HCMBL, the frequency of somatically mutated genes at diagnosis is lower than that of CLL. Accounting for both the number of mutated genes and CLL-IPI can identify individuals with HCMBL with more aggressive clinical course., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Exportin-1 (XPO1), the main soluble nuclear export receptor in eukaryotic cells, is frequently overexpressed in diffuse large B-cell lymphoma (DLBCL). A selective XPO1 inhibitor, selinexor, received approval as single agent for relapsed or refractory (R/R) DLBCL. Elucidating the mechanisms by which XPO1 overexpression supports cancer cells could facilitate further clinical development of XPO1 inhibitors. We uncovered here that XPO1 overexpression increases tolerance to genotoxic stress, leading to a poor response to chemoimmunotherapy. Upon DNA damage induced by MYC expression or exogenous compounds, XPO1 bound and exported EIF4E and THOC4 carrying DNA damage repair mRNAs, thereby increasing synthesis of DNA damage repair proteins under conditions of increased turnover. Consequently, XPO1 inhibition decreased the capacity of lymphoma cells to repair DNA damage and ultimately resulted in increased cytotoxicity. In a phase I clinical trial conducted in R/R DLBCL, the combination of selinexor with second-line chemoimmunotherapy was tolerated with early indication of efficacy. Overall, this study reveals that XPO1 overexpression plays a critical role in the increased tolerance of cancer cells to DNA damage while providing new insights to optimize the clinical development of XPO1 inhibitors., Significance: XPO1 regulates the dynamic ribonucleoprotein nuclear export in response to genotoxic stress to support tolerance and can be targeted to enhance the sensitivity of cancer cells to endogenous and exogenous DNA damage. See related commentary by Knittel and Reinhardt, p. 3., (©2023 The Authors; Published by the American Association for Cancer Research.)

The B cell leukemia/lymphoma 2 (BCL-2) inhibitor venetoclax is effective in chronic lymphocytic leukemia (CLL); however, resistance may develop over time. Other lymphoid malignancies such as diffuse large B cell lymphoma (DLBCL) are frequently intrinsically resistant to venetoclax. Although genomic resistance mechanisms such as BCL2 mutations have been described, this probably only explains a subset of resistant cases. Using 2 complementary functional precision medicine techniques - BH3 profiling and high-throughput kinase activity mapping - we found that hyperphosphorylation of BCL-2 family proteins, including antiapoptotic myeloid leukemia 1 (MCL-1) and BCL-2 and proapoptotic BCL-2 agonist of cell death (BAD) and BCL-2 associated X, apoptosis regulator (BAX), underlies functional mechanisms of both intrinsic and acquired resistance to venetoclax in CLL and DLBCL. Additionally, we provide evidence that antiapoptotic BCL-2 family protein phosphorylation altered the apoptotic protein interactome, thereby changing the profile of functional dependence on these prosurvival proteins. Targeting BCL-2 family protein phosphorylation with phosphatase-activating drugs rewired these dependencies, thus restoring sensitivity to venetoclax in a panel of venetoclax-resistant lymphoid cell lines, a resistant mouse model, and in paired patient samples before venetoclax treatment and at the time of progression.

Although chemoimmunotherapy is the current standard of care for initial treatment of mantle cell lymphoma (MCL), newer data suggest that there may be a role for a chemotherapy-free approach. We report the 9-year follow-up results of a multicenter, phase 2 study of lenalidomide plus rituximab (LR) as the initial treatment of MCL. The LR doublet is used as induction and maintenance until progression, with optional discontinuation after 3 years. We previously reported an overall response rate of 92% in evaluable patients, with 64% achieving a complete response. At a median follow-up of 103 months, 17 of 36 evaluable patients (47%) remain in remission. The 9-year progression-free survival and overall survival were 51% and 66%, respectively. During maintenance, hematologic adverse events included asymptomatic grade 3 or 4 cytopenia (42% neutropenia, 5% thrombocytopenia, and 3% anemia) and mostly grade 1 to 2 infections managed in the outpatient setting (50% upper respiratory infections, 21% urinary tract infections, 16% sinusitis, 16% cellulitis, and 13% pneumonia, with 5% requiring hospitalization). More patients developed grade 1 and 2 neuropathy during maintenance therapy (29%) than during induction therapy (8%). Twenty-one percent of patients developed secondary malignancies, including 5% with invasive malignancies, whereas the remainder were noninvasive skin cancers treated with local skin-directed therapy. Two patients permanently discontinued therapy because of concerns of immunosuppression during the COVID-19 pandemic. With long-term follow-up, LR continues to demonstrate prolonged, durable responses with manageable safety as initial induction therapy. This trial was registered at www.clinicaltrials.gov as #NCT01472562., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

ELEVATE-RR demonstrated noninferior progression-free survival and lower incidence of key adverse events (AEs) with acalabrutinib vs ibrutinib in previously treated chronic lymphocytic leukemia. We further characterize AEs of acalabrutinib and ibrutinib via post hoc analysis. Overall and exposure-adjusted incidence rate was assessed for common Bruton tyrosine kinase inhibitor-associated AEs and for selected events of clinical interest (ECIs). AE burden scores based on previously published methodology were calculated for AEs overall and selected ECIs. Safety analyses included 529 patients (acalabrutinib, n = 266; ibrutinib, n = 263). Among common AEs, incidences of any-grade diarrhea, arthralgia, urinary tract infection, back pain, muscle spasms, and dyspepsia were higher with ibrutinib, with 1.5- to 4.1-fold higher exposure-adjusted incidence rates. Incidences of headache and cough were higher with acalabrutinib, with 1.6- and 1.2-fold higher exposure-adjusted incidence rate, respectively. Among ECIs, incidences of any-grade atrial fibrillation/flutter, hypertension, and bleeding were higher with ibrutinib, as were exposure-adjusted incidence rates (2.0-, 2.8-, and 1.6-fold, respectively); incidences of cardiac events overall (the Medical Dictionary for Regulatory Activities system organ class) and infections were similar between arms. Rate of discontinuation because of AEs was lower for acalabrutinib (hazard ratio, 0.62; 95% confidence interval, 0.41-0.93). AE burden score was higher for ibrutinib vs acalabrutinib overall and for the ECIs atrial fibrillation/flutter, hypertension, and bleeding. A limitation of this analysis is its open-label study design, which may influence the reporting of more subjective AEs. Overall, event-based analyses and AE burden scores demonstrated higher AE burden overall and specifically for atrial fibrillation, hypertension, and hemorrhage with ibrutinib vs acalabrutinib. This trial was registered at www.clinicaltrials.gov as #NCT02477696., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory checkpoint receptor that negatively regulates Tcell responses. CD226 competes with TIGIT for binding to the CD155 ligand, delivering a positive signal to the T cell. Here we studied the expression of TIGIT and CD226 in a cohort of 115 patients with chronic lymphocytic leukemia (CLL) and report expression of TIGIT and CD226 by leukemic cells. By devising a TIGIT/CD226 ratio, we showed that CLL cells favoring TIGIT over CD226 are typical of a more indolent disease, while those favoring CD226 are characterized by a shorter time to first treatment and shorter progression-free survival after first treatment. TIGIT expression was inversely correlated to the B-cell receptor (BCR) signaling capacity, as determined by studying BTK phosphorylation, cell proliferation and interleukin- 10 production. In CLL cells treated with ibrutinib, in which surface IgM and BCR signaling capacity are temporarily increased, TIGIT expression was downmodulated, in line with data indicating transient recovery from anergy. Lastly, cells from patients with Richter syndrome were characterized by high levels of CD226, with low to undetectable TIGIT, in keeping with their high proliferative drive. Together, these data suggest that TIGIT contributes to CLL anergy by downregulating BCR signaling, identifying novel and actionable molecular circuits regulating anergy and modulating CLL cell functions.

Acalabrutinib is a Bruton tyrosine kinase (BTK) inhibitor approved to treat adults with chronic lymphocytic leukemia, small lymphocytic lymphoma, or previously treated mantle cell lymphoma. As the bioavailability of the acalabrutinib capsule (AC) depends on gastric pH for solubility and is impaired by acid-suppressing therapies, coadministration with proton-pump inhibitors (PPIs) is not recommended. Three studies in healthy subjects (N = 30, N = 66, N = 20) evaluated the pharmacokinetics (PKs), pharmacodynamics (PDs), safety, and tolerability of acalabrutinib maleate tablet (AT) formulated with pH-independent release. Subjects were administered AT or AC (orally, fasted state), AT in a fed state, or AT in the presence of a PPI, and AT or AC via nasogastric (NG) route. Acalabrutinib exposures (geometric mean [% coefficient of variation, CV]) were comparable for AT versus AC (AUC inf 567.8 ng h/mL [36.9] vs 572.2 ng h/mL [38.2], C max 537.2 ng/mL [42.6] vs 535.7 ng/mL [58.4], respectively); similar results were observed for acalabrutinib's active metabolite (ACP-5862) and for AT-NG versus AC-NG. The geometric mean C max for acalabrutinib was lower when AT was administered in the fed versus the fasted state (C max 255.6 ng/mL [%CV, 46.5] vs 504.9 ng/mL [49.9]); AUCs were similar. For AT + PPI, geometric mean C max was lower (371.9 ng/mL [%CV, 81.4] vs 504.9 ng/mL [49.9]) and AUC inf was higher (AUC inf 694.1 ng h/mL [39.7] vs 559.5 ng h/mL [34.6]) than AT alone. AT and AC were similar in BTK occupancy. Most adverse events were mild with no new safety concerns. Acalabrutinib formulations were comparable and AT could be coadministered with PPIs, food, or via NG tube without affecting the PKs or PDs., (© 2022 AstraZeneca. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Cardiovascular (CV) toxicities of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib may limit use of this effective therapy in patients with chronic lymphocytic leukemia (CLL). Acalabrutinib is a second-generation BTK inhibitor with greater BTK selectivity. This analysis characterizes pooled CV adverse events (AE) data in patients with CLL who received acalabrutinib monotherapy in clinical trials (clinicaltrials gov. Identifier: NCT02029443, NCT02475681, NCT02970318 and NCT02337829). Acalabrutinib was given orally at total daily doses of 100-400 mg, later switched to 100 mg twice daily, and continued until disease progression or toxicity. Data from 762 patients (median age: 67 years [range, 32-89]; median follow-up: 25.9 months [range, 0-58.5]) were analyzed. Cardiac AE of any grade were reported in 129 patients (17%; grade ≥3, n=37 [5%]) and led to treatment discontinuation in seven patients (1%). The most common any-grade cardiac AE were atrial fibrillation/flutter (5%), palpitations (3%), and tachycardia (2%). Overall, 91% of patients with cardiac AE had CV risk factors before acalabrutinib treatment. Among 38 patients with atrial fibrillation/flutter events, seven (18%) had prior history of arrhythmia or atrial fibrillation/flutter. Hypertension AE were reported in 67 patients (9%), 43 (64%) of whom had a preexisting history of hypertension; no patients discontinued treatment due to hypertension. No sudden cardiac deaths were reported. Overall, these data demonstrate a low incidence of new-onset cardiac AE with acalabrutinib in patients with CLL. Findings from the head-to-head, randomized trial of ibrutinib and acalabrutinib in patients with highrisk CLL (clinicaltrials gov. Identifier: NCT02477696) prospectively assess differences in CV toxicity between the two agents.

Purpose: BCL2 is overexpressed and confers prosurvival signaling in malignant lymphoplasmacytic cells in Waldenström macroglobulinemia (WM). Venetoclax is a potent BCL2 antagonist and triggers in vitro apoptosis of WM cells. The activity of venetoclax in WM remains to be clarified., Patients and Methods: We performed a multicenter, prospective phase II study of venetoclax in patients with previously treated WM (NCT02677324). Venetoclax was dose-escalated from 200 mg to a maximum dose of 800 mg daily for up to 2 years., Results: Thirty-two patients were evaluable, including 16 previously exposed to Bruton tyrosine kinase inhibitors (BTKis). All patients were MYD88 L265P -mutated, and 17 carried CXCR4 mutations. The median time to minor and major responses was 1.9 and 5.1 months, respectively. Previous exposure to BTKis was associated with a longer time to response (4.5 v 1.4 months; P < .001). The overall, major, and very good partial response rates were 84%, 81%, and 19%, respectively. The major response rate was lower in those with refractory versus relapsed disease (50% v 95%; P = .007). The median follow-up time was 33 months, and the median progression-free survival was 30 months. CXCR4 mutations did not affect treatment response or progression-free survival. The only recurring grade ≥ 3 treatment-related adverse event was neutropenia (n = 14; 45%), including one episode of febrile neutropenia. Laboratory tumor lysis without clinical sequelae occurred in one patient. No deaths have occurred., Conclusion: Venetoclax is safe and highly active in patients with previously treated WM, including those who previously received BTKis. CXCR4 mutation status did not affect treatment response., Competing Interests: Jorge J. CastilloConsulting or Advisory Role: Janssen, Roche/Genentech, Beigene, AbbVie/PharmacyclicsResearch Funding: Pharmacyclics (Inst), AbbVie (Inst), Janssen (Inst), BeiGene (Inst), TG Therapeutics (Inst) John N. AllanHonoraria: AstraZeneca, AbbVie, Pharmacyclics/Janssen, BeiGeneConsulting or Advisory Role: AbbVie/Genentech, Pharmacyclics, Ascentage Pharma, BeiGene, Janssen Oncology, Epizyme, AstraZeneca, TG Therapeutics, ADC TherapeuticsResearch Funding: Genentech, Janssen, Celgene, TG Therapeutics Tanya SiddiqiConsulting or Advisory Role: Juno Therapeutics, AstraZeneca, BeiGene, Celgene, Pharmacyclics, Bristol Myers Squibb/CelgeneSpeakers' Bureau: Pharmacyclics/Janssen, AstraZeneca, BeiGene, Bristol Myers Squibb/CelgeneResearch Funding: Juno Therapeutics (Inst), Kite, a Gilead company (Inst), Acerta Pharma (Inst), TG Therapeutics (Inst), BeiGene (Inst), Pharmacyclics (Inst), Celgene (Inst), Oncternal Therapeutics (Inst), Bristol-Myers Squibb/Sanofi (Inst) Ranjana H. AdvaniConsulting or Advisory Role: Genentech/Roche, Seattle Genetics, Takeda, Portola Pharmaceuticals, Celgene, Sanofi, Kura Oncology, Merck, Karyopharm Therapeutics, ADC Therapeutics, Daiichi Sankyo, Bristol Myers Squibb/Celgene, Epizyme, IncyteResearch Funding: Millennium (Inst), Seattle Genetics (Inst), Genentech/Roche (Inst), Pharmacyclics (Inst), Janssen (Inst), Merck (Inst), Kura Oncology (Inst), Forty Seven (Inst), Cyteir (Inst) Catherine A. FlynnConsulting or Advisory Role: Pharmacyclics, Karyopharm Therapeutics Shayna SarosiekResearch Funding: Acrotech Biopharma (Inst) Andrew R. BranaganConsulting or Advisory Role: Pharmacyclics/Janssen, Genzyme, Adaptive Biotechnologies, BeiGene, Karyopharm Therapeutics, CSL Behring Xia LiuEmployment: Merck (I) Guang YangEmployment: AbbVie (I), Blueprint MedicinesStock and Other Ownership Interests: Blueprint MedicinesHonoraria: Janssen Matthew S. DavidsHonoraria: Research to PracticeConsulting or Advisory Role: Genentech, Janssen, Pharmacyclics, TG Therapeutics, AbbVie, AstraZeneca, Celgene, MEI Pharma, Adaptive Biotechnologies, Verastem, Ascentage Pharma, BeiGene, Lilly, Novartis, Takeda, Bristol Myers SquibbResearch Funding: Genentech (Inst), TG Therapeutics (Inst), Pharmacyclics (Inst), Surface Oncology (Inst), MEI Pharma (Inst), Verastem (Inst), Ascentage Pharma (Inst), AstraZeneca (Inst), Novartis (Inst)Travel, Accommodations, Expenses: TG Therapeutics, Janssen, AbbVie, BeiGene, Genentech Richard R. FurmanHonoraria: Janssen, AstraZeneca, Pharmacyclics, Janssen Biotech, Genentech/Roche, Loxo, TG Therapeutics, Verastem, Acerta Pharma, AstraZeneca, Beigene, Incyte, OncoTracker, AbbVie, MorphoSys, SanofiResearch Funding: Acerta Pharma, TG TherapeuticsExpert Testimony: AbbVie, Janssen OncologyTravel, Accommodations, Expenses: TG Therapeutics, Janssen OncologyOther Relationship: Incyte, Janssen Biotech Steven P. TreonHonoraria: Abbvie/Pharmacyclics, Janssen Oncology, BeiGeneConsulting or Advisory Role: Janssen, Pharmacyclics, Beigene, X4 Pharmaceuticals, Bristol Myers SquibbResearch Funding: Pharmacyclics, Bristol Myers Squibb (Inst), X4 Pharmaceuticals (Inst), Lilly (Inst), Beigene (Inst), AbbVie (Inst)Patents, Royalties, Other Intellectual Property: My institution holds patents related to use of MYD88 and CXCR4 testing for which a predetermined financial distribution to the laboratory and individuals is provided. I have not received any income to this date related to these patents (Inst)Travel, Accommodations, Expenses: Janssen OncologyOther Relationship: Janssen, Pharmacyclics, BeigeneNo other potential conflicts of interest were reported.

Monoclonal B-cell lymphocytosis (MBL) is a precursor to CLL. Other than age, sex, and CLL family-history, little is known about factors associated with MBL risk. A polygenic-risk-score (PRS) of 41 CLL-susceptibility variants has been found to be associated with CLL risk among individuals of European-ancestry(EA). Here, we evaluate these variants, the PRS, and environmental factors for MBL risk. We also evaluate these variants and the CLL-PRS among African-American (AA) and EA-CLL cases and controls. Our study included 560 EA MBLs, 869 CLLs (696 EA/173 AA), and 2866 controls (2631 EA/235 AA). We used logistic regression, adjusting for age and sex, to estimate odds ratios (OR) and 95% confidence intervals within each race. We found significant associations with MBL risk among 21 of 41 variants and with the CLL-PRS (OR = 1.86, P = 1.9 × 10 -29 , c-statistic = 0.72). Little evidence of any association between MBL risk and environmental factors was observed. We observed significant associations of the CLL-PRS with EA-CLL risk (OR = 2.53, P = 4.0 × 10 -63 , c-statistic = 0.77) and AA-CLL risk (OR = 1.76, P = 5.1 × 10 -5 , c-statistic = 0.62). Inherited genetic factors and not environmental are associated with MBL risk. In particular, the CLL-PRS is a strong predictor for both risk of MBL and EA-CLL, but less so for AA-CLL supporting the need for further work in this population., (© 2021. The Author(s).)

BACKGROUND: Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncofetal protein present on many cancers. Zilovertamab vedotin (ZV) is an antibody–drug conjugate comprising a monoclonal antibody recognizing extracellular ROR1, a cleavable linker, and the anti-microtubule cytotoxin monomethyl auristatin E. METHODS: In this phase 1, first-in-human, dose-escalation study, we accrued patients with previously treated lymphoid cancers to receive ZV every 3 weeks until the occurrence of cancer progression or unacceptable toxicity had occurred. RESULTS: We enrolled 32 patients with tumor histologies of mantle cell lymphoma (MCL) (n=15), chronic lymphocytic leukemia (n=7), diffuse large B-cell lymphoma (DLBCL) (n=5), follicular lymphoma (n=3), Richter transformation lymphoma (n=1), or marginal zone lymphoma (n=1). Patients had received a median of four previous drug and/or cellular therapies. Starting dose levels were 0.5 (n=1), 1.0 (n=3), 1.5 (n=3), 2.25 (n=11), and 2.5 (n=14) mg per kg of body weight (mg/kg). Pharmacokinetic and pharmacodynamic data documented systemic ZV exposure and exposure-dependent ZV targeting of ROR1 on circulating tumor cells. As expected with an monomethyl auristatin E-containing antibody–drug conjugate, adverse events (AEs) included acute neutropenia and cumulative neuropathy resulting in a recommended ZV dosing regimen of 2.5 mg/kg every 3 weeks. No clinically concerning AEs occurred to suggest ROR1-mediated toxicities or nonspecific ZV binding to normal tissues. ZV induced objective tumor responses in 7 of 15 patients with MCL (47%; 4 partial and 3 complete) and in 3 of 5 patients with DLBCL (60%; 1 partial and 2 complete); objective tumor responses were not observed among patients with other tumor types. CONCLUSIONS: In heavily pretreated patients, ZV demonstrated no unexpected toxicities and showed evidence of antitumor activity, providing clinical proof of concept for selective targeting of ROR1 as a potential new approach to cancer therapy. (ClinicalTrials.gov number, NCT03833180.)

Idelalisib is associated with increased occurrence of immune-related adverse events (irAEs). Clinical observations suggest a correlation between immune checkpoint inhibitor-induced irAEs and survival outcomes in patients with solid tumors; however, this relationship in hematologic malignancies is not well understood. In a post hoc analysis of 3 registrational trials, we explored the relationship between Grade ≥3 diarrhea/colitis and alanine/aspartate transaminase (ALT/AST) elevation incidences and efficacy endpoints in patients with indolent non-Hodgkin lymphoma (iNHL), follicular lymphoma (FL), and chronic lymphocytic leukemia treated with idelalisib. Grade ≥3 diarrhea/colitis was associated with higher overall response rate (ORR) and longer progression-free survival (PFS) for all subgroups. Grade ≥3 ALT/AST elevations were associated with improved duration of response and overall survival for all subgroups and improved ORR and PFS for patients with FL or iNHL. Our analysis in hematologic malignancies showed a trend correlating idelalisib-induced Grade ≥3 irAEs with improved efficacy.

Background: Patients with chronic lymphocytic leukaemia who progress to Richter transformation (diffuse large B-cell lymphoma morphology) have few therapeutic options. We analysed data from the Richter transformation cohort of a larger, ongoing, phase 1-2, single-arm study evaluating the safety and activity of the selective, irreversible Bruton's tyrosine kinase inhibitor acalabrutinib for the treatment of chronic lymphocytic leukaemia or small lymphocytic lymphoma., Methods: For this open-label, single-arm, phase 1-2 study, patients aged 18 years or older with biopsy-proven treatment-naive or previously treated diffuse large B-cell lymphoma (Richter transformation) or prolymphocytic leukaemia transformation (Eastern Cooperative Oncology Group performance status ≤2) were assigned to receive oral acalabrutinib 200 mg twice daily as monotherapy until disease progression or toxicity. Patients were enrolled across seven centres from four countries. Safety and pharmacokinetics were assessed as primary endpoints; secondary endpoints were overall response rate, duration of response, and progression-free survival. Safety was assessed in the all-treated population (patients who received ≥1 dose), and activity was assessed in the all-treated population (for progression-free survival) and efficacy-evaluable population (for response rate; patients in the all-treated population with ≥1 response assessment after the first dose). This trial is registered with ClinicalTrials.gov (NCT02029443)., Findings: Between Sept 2, 2014, and April 25, 2016, 25 patients with Richter transformation were enrolled; 12 (48%) were male and 23 (92%) were White. As of data cutoff (March 1, 2021), two (8%) of 25 patients remained on acalabrutinib. The median time on study was 2·6 months (IQR 1·8-8·4). The most common adverse events (all grades) were diarrhoea (12 [48%] of 25 patients), headache (11 [44%]), and anaemia (eight [32%]). The most common grade 3-4 adverse events were neutropenia (seven [28%] of 25) and anaemia (five [20%]). The most common reason for treatment discontinuation was disease progression (17 [68%] of 25 patients). 11 (44%) deaths were reported within 30 days of the last acalabrutinib dose; none was considered treatment-related. Acalabrutinib was rapidly absorbed and eliminated, with similar day 1 and day 8 exposures. The overall response rate was 40·0% (95% CI 21·1-61·3), with two (8%) of 25 patients having a complete response and eight (32%) having a partial response; the median duration of response was 6·2 months (95% CI 0·3-14·8). Median progression-free survival in the overall cohort was 3·2 months (95% CI 1·8-4·0)., Interpretation: Acalabrutinib appears to be generally well tolerated, although progression-free survival was relatively poor in this cohort of patients with Richter transformation. On the basis of these findings, the use of acalabrutinib monotherapy in this setting is limited; however, further assessment of acalabrutinib as part of combination-based regimens for patients with Richter transformation is warranted., Funding: Acerta Pharma, a member of the AstraZeneca Group., Competing Interests: Declaration of interests TAE reports grants from AstraZeneca and BeiGene; consulting fees from Kite, Gilead, BeiGene, Incyte, Secura, and Roche; honoraria from Janssen, AbbVie, AstraZeneca, Loxo, Incyte, and Roche; and a leadership or fiduciary role in other board, society, committee or advocacy groups for Loxo Oncology. AS reports honoraria from AstraZeneca, Roche, Janssen, and AbbVie; and unrestricted education grants from Janssen and AstraZeneca. WGW reports research funding from GlaxoSmithKline/Novartis, AbbVie, Genentech, Pharmacyclics, AstraZeneca/Acerta Pharma, Gilead, Juno, Kite, Sunesis, Miragen, Oncternal, Cyclacel, Loxo, Janssen, and Xencor. JRB reports consultancy for AbbVie, Acerta/AstraZeneca, BeiGene, Bristol Myers Squibb/Juno/Celgene, Catapult, Dynamo, Eli Lilly, Genentech/Roche, Hutchmed, Janssen, Kite, Loxo, MEI Pharma, MorphoSys AG, Nextcea, Novartis, Octapharma, Pfizer, Pharmacyclics, Rigel, TG Therapeutics, and Verastem; honoraria from Janssen; research funding from Gilead, Loxo/Lilly, Sun, and Verastem/SecuraBio; and participation on data safety monitoring committees for Invectys and MorphoSys. PG reports support for the present work by Acerta and AstraZeneca; research funding from AbbVie, Gilead, Janssen, and Sunesis; consulting fees from AbbVie, AstraZeneca, ArQule/MSD, BeiGene, Janssen, Lilly/Loxo, and Roche; honoraria from AbbVie, AstraZeneca, ArQule/MSD, BeiGene, Janssen, Lilly/Loxo, and Roche; and participation on a data safety monitoring board or advisory board for Hovon and the German CLL Study Group. JMP reports consulting fees, travel support, and honorarium from Adaptive, AstraZeneca, BeiGene, Gilead/Kite, Incyte, and Epizyme. RRF reports consulting fees from AbbVie, AstraZeneca/Acerta Pharma, BeiGene, Genentech, Janssen, Pharmacyclics, Loxo, MorphoSys, Sanofi, X4 Pharmaceuticals, and TG Therapeutics; honoraria from AbbVie, AstraZeneca/Acerta Pharma, BeiGene, and Janssen; fees for expert testimony from AbbVie, Janssen, and Pharmacyclics; and participation on a data safety monitoring board or advisory board for Incyte. PP reports previous employment by Acerta Pharma/AstraZeneca during the time the research was done and stock ownership in Acerta Pharma/AstraZeneca. MHW reports employment by and stock ownership in AstraZeneca. JC reports support for the present work by Acerta and AstraZeneca and stock ownership in Acerta and Kartos. YX reports previous employment by AstraZeneca during the time the research was done. RI reports previous employment by Acerta Pharma/AstraZeneca during the time the research was done, is a patent holder for acalabrutinib, and is a stockholder of Acerta Pharma and AstraZeneca. AH reports previous employment by Acerta Pharma during the time the research was done, has patents pending, and is a stockholder of Acerta Pharma. PH reports research support from Janssen, AbbVie, Pharmacyclics, Gilead, and Roche; and fees for speaking for Janssen and AbbVie. JCB reports support for the present work by Acerta and AstraZeneca; consulting fees from Astellas, Pharmacyclics, Syndax, and Trillium; honoraria from Acerta and AstraZeneca; travel support from AstraZeneca; participation on a data safety monitoring board or advisory board for Kartos; a leadership or fiduciary role in other board, society, committee or advocacy groups for Hendrix College; and stock ownership in Vincerx., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Bruton tyrosine kinase (BTK) inhibitors represent an important therapeutic advancement for B cell malignancies. Ibrutinib, the first-in-class BTK inhibitor, is approved by the US FDA to treat patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), and mantle cell lymphoma (MCL; after ≥1 prior therapy); and by the European Medicines Agency (EMA) for adult patients with relapsed/refractory (R/R) MCL and patients with CLL. Ibrutinib treatment can be limited by adverse events (AEs) including atrial fibrillation, arthralgias, rash, diarrhea, and bleeding events, leading to drug discontinuation in 4%-26% of patients. Acalabrutinib, a second-generation BTK inhibitor, is approved by the FDA to treat adult patients with CLL/SLL or MCL (relapsed after 1 prior therapy); and by the EMA to treat adult patients with CLL or R/R MCL. The most common AE associated with acalabrutinib is headache of limited duration, which occurs in 22%-51% of patients, and is mainly grade 1-2 in severity, with only 1% of patients experiencing grade ≥3 headache. Furthermore, acalabrutinib is associated with a low incidence of atrial fibrillation. Zanubrutinib, a selective next-generation covalent BTK inhibitor, is approved by the FDA to treat adult patients with MCL who have received ≥1 prior therapy, and is under investigation for the treatment of patients with CLL. In the phase 3 SEQUOIA trial in patients with CLL, the most common grade ≥3 AEs were neutropenia/neutrophil count decreased and infections. This review provides an overview of BTK inhibitor-related AEs in patients with CLL, and strategies for their management., Competing Interests: SO has served as a consultant for Amgen, Astellas, Celgene, GlaxoSmithKline, Janssen Oncology, Aptose Biosciences Inc, Vaniam Group LLC, AbbVie, and Alexion; has received research support from Kite Pharma, Regeneron, and Acerta Pharma; and has been a consultant and received research support from Gilead, Pharmacyclics, TG Therapeutics, Pfizer, and Sunesis. JBr has served as a consultant for AbbVie, Acerta, AstraZeneca, BeiGene, Catapult, Dynamo Therapeutics, Eli Lilly, Juno/Celgene, Kite, MEI Pharma, Nextcea, Novartis, Octapharma, Pfizer, Rigel, Sunesis, TG Therapeutics, and Verastem; received honoraria from Janssen; received research funding from Gilead, Loxo, Sun, and Verastem; and served on data safety monitoring committees (DSMC) for Invectys. JBy reports personal fees from Acerta Pharma (a member of the AstraZeneca Group), Genentech, Janssen, and Pharmacyclics. RF reports consulting fees from AbbVie, Acerta, AstraZeneca, BeiGene, Genentech, Janssen, Loxo Oncology, Morphosys, OncoTarget, Pharmacyclics, Sanofi, Sunesis, TG Therapeutics, and Verastem; DSMC: Incyte; and speaker fees from Janssen. PG reports consulting or advisory fees from AbbVie, BeiGene, Janssen Oncology, Gilead Sciences, Juno Therapeutics, Sunesis Pharmaceuticals, ArQule, Adaptive Biotechnologies, MEI Pharma, and Acerta Pharma/AstraZeneca; and research funding from: AbbVie, Janssen Oncology, Gilead Sciences, and Novartis. JS reports personal fees from AbbVie, Acerta Pharma (a member of the AstraZeneca Group), AstraZeneca, Genentech, Pharmacyclics, Sunesis, and TG Therapeutics. WW has received research funding from AbbVie, Acerta Pharma, Genentech, Gilead, GlaxoSmithKline/Novartis, Janssen, Juno, Kite, and Pharmacyclics., (Copyright © 2021 O’Brien, Brown, Byrd, Furman, Ghia, Sharman and Wierda.)

Purpose: Among Bruton's tyrosine kinase inhibitors, acalabrutinib has greater selectivity than ibrutinib, which we hypothesized would improve continuous therapy tolerability. We conducted an open-label, randomized, noninferiority, phase III trial comparing acalabrutinib and ibrutinib in patients with chronic lymphocytic leukemia (CLL)., Methods: Patients with previously treated CLL with centrally confirmed del(17)(p13.1) or del(11)(q22.3) were randomly assigned to oral acalabrutinib 100 mg twice daily or ibrutinib 420 mg once daily until progression or unacceptable toxicity. The primary end point was independent review committee-assessed noninferiority of progression-free survival (PFS)., Results: Overall, 533 patients (acalabrutinib, n = 268; ibrutinib, n = 265) were randomly assigned. At the data cutoff, 124 (46.3%) acalabrutinib patients and 109 (41.1%) ibrutinib patients remained on treatment. After a median follow-up of 40.9 months, acalabrutinib was determined to be noninferior to ibrutinib with a median PFS of 38.4 months in both arms (95% CI acalabrutinib, 33.0 to 38.6 and ibrutinib, 33.0 to 41.6; hazard ratio: 1.00; 95% CI, 0.79 to 1.27). All-grade atrial fibrillation/atrial flutter incidence was significantly lower with acalabrutinib versus ibrutinib (9.4% v 16.0%; P = .02); among other selected secondary end points, grade 3 or higher infections (30.8% v 30.0%) and Richter transformations (3.8% v 4.9%) were comparable between groups and median overall survival was not reached in either arm (hazard ratio, 0.82; 95% CI, 0.59 to 1.15), with 63 (23.5%) deaths with acalabrutinib and 73 (27.5%) with ibrutinib. Treatment discontinuations because of adverse events occurred in 14.7% of acalabrutinib-treated patients and 21.3% of ibrutinib-treated patients., Conclusion: In this first direct comparison of less versus more selective Bruton's tyrosine kinase inhibitors in CLL, acalabrutinib demonstrated noninferior PFS with fewer cardiovascular adverse events., Competing Interests: John C. ByrdStock and Other Ownership Interests: Vincerx PharmaHonoraria: Pharmacyclics, AstraZeneca, Novartis, Syndax, Trillium TherapeuticsConsulting or Advisory Role: Acerta Pharma, Janssen, Kura Oncology, Novartis, Syndax, AstraZenecaResearch Funding: Acerta Pharma, Pharmacyclics, ZencorPatents, Royalties, Other Intellectual Property: OSU PatentsTravel, Accommodations, Expenses: Gilead Sciences, Janssen, Novartis, Pharmacyclics, TG Therapeutics Peter HillmenHonoraria: Janssen, AbbVie, RocheResearch Funding: Janssen, Pharmacyclics, Roche, Gilead Sciences, AbbVieTravel, Accommodations, Expenses: Janssen, AbbVie Paolo GhiaHonoraria: AbbVie, BeiGene, Janssen Oncology, Gilead Sciences, Juno Therapeutics, Sunesis Pharmaceuticals, ArQule, Adaptive Biotechnologies, Dynamo Therapeutics, MEI Pharma, Acerta Pharma/AstraZeneca, Juno/Celgene/Bristol Myers Squibb, MSD, Lilly, RocheConsulting or Advisory Role: AbbVie, BeiGene, Janssen, Gilead Sciences, Sunesis Pharmaceuticals, Juno Therapeutics, ArQule, Adaptive Biotechnologies, Dynamo Therapeutics, MEI Pharma, Acerta Pharma/AstraZeneca, MSD, Lilly, RocheResearch Funding: AbbVie, Janssen Oncology, Gilead Sciences, Sunesis Pharmaceuticals, Novartis, AstraZeneca Arnon P. KaterConsulting or Advisory Role: Janssen Oncology, AbbVie/Genentech, AstraZeneca, Bristol Myers Squibb/Celgene, Lava TherapeuticsResearch Funding: Janssen Oncology, Roche/Genentech, Bristol Myers Squibb/Celgene, AbbVie, AstraZenecaTravel, Accommodations, Expenses: Acerta Pharma/AstraZeneca, Roche/Genentech Asher Chanan-KhanStock and Other Ownership Interests: Matthew & Asher Inc, NanoDev Therapeutics, STARTON TherapeuticsHonoraria: BeiGene, Ascentage PharmaResearch Funding: Ascentage PharmaPatents, Royalties, Other Intellectual Property: Patent on PSMB9 biomarker Richard R. FurmanHonoraria: Janssen, AstraZenecaConsulting or Advisory Role: Pharmacyclics, Janssen Biotech, Genentech/Roche, Loxo, TG Therapeutics, Verastem, Acerta Pharma, AstraZeneca, Beigene, Incyte, OncoTracker, AbbVie, MorphoSys, SanofiResearch Funding: Acerta Pharma, TG TherapeuticsExpert Testimony: AbbVie, Janssen OncologyTravel, Accommodations, Expenses: TG Therapeutics, Janssen OncologyOther Relationship: Incyte, Janssen Biotech Susan O'BrienEmployment: University of California, IrvineHonoraria: Celgene, Janssen, Pharmacyclics, Gilead Sciences, Pfizer, Amgen, Astellas Pharma, GlaxoSmithKline, Aptose Biosciences, Vaniam Group, AbbVie, Sunesis Pharmaceuticals, Alexion Pharmaceuticals, Eisai, TG Therapeutics, Nova Research CompanyConsulting or Advisory Role: Amgen, Celgene, GlaxoSmithKline, Janssen Oncology, Aptose Biosciences, Vaniam Group, AbbVie/Genentech, Sunesis Pharmaceuticals, Alexion Pharmaceuticals, Astellas Pharma, Gilead Sciences, Pharmacyclics, TG Therapeutics, Pfizer, Sunesis PharmaceuticalsResearch Funding: Acerta Pharma, Regeneron, Gilead Sciences, Pfizer, TG Therapeutics, Pharmacyclics, Kite, a Gilead company, Sunesis PharmaceuticalsTravel, Accommodations, Expenses: Celgene, Janssen, Gilead Sciences, Regeneron, Janssen Oncology Mustafa Nuri YenerelConsulting or Advisory Role: Pfizer, Alexion PharmaceuticalsSpeakers' Bureau: Janssen OncologyTravel, Accommodations, Expenses: Pfizer Arpad IllésConsulting or Advisory Role: Janssen, Takeda, Novartis, Pfizer, Roche, CelgeneResearch Funding: Takeda, Seattle GeneticsTravel, Accommodations, Expenses: Novartis, Janssen, Pfizer, Roche Neil KayConsulting or Advisory Role: MorphoSys, Celgene, Agios, CytomX Therapeutics, AstraZeneca, Pharmacyclics, DAVA Pharmaceuticals, Juno Therapeutics, Rigel, Oncotracker, Bristol Myers Squibb, AbbVie, Targeted Oncology, Acerta Pharma/AstraZeneca, MEI Pharma, Sunesis Pharmaceuticals, TG Therapeutics, Tolero Pharmaceuticals, Janssen Biotech, Genentech/AbbVieResearch Funding: Pharmacyclics/Janssen, Tolero Pharmaceuticals, Acerta Pharma, MEI Pharma, Celgene, Genentech, Sunesis Pharmaceuticals, AbbVie, TG Therapeutics, Bristol Myers Squibb Jose A. Garcia-MarcoConsulting or Advisory Role: AbbVie, Janssen, AstraZeneca SpainSpeakers' Bureau: AbbVie, Janssen, AstraZeneca SpainResearch Funding: AbbVie, JanssenTravel, Accommodations, Expenses: AbbVie, Janssen Anthony MatoConsulting or Advisory Role: TG Therapeutics, AbbVie/Genentech, Celgene, Pharmacyclics, Adaptive Biotechnologies, Verastem, Johnson & Johnson, Acerta Pharma/AstraZeneca, DTRM, Loxo/Lilly, Curio/Vaniam Group, Merck, Bristol Myers Squibb/PfizerResearch Funding: Regeneron, TG Therapeutics, Sunesis Pharmaceuticals, LOXO, AbbVie/Genentech, Pharmacyclics, Adaptive Biotechnologies, Johnson & Johnson, Acerta Pharma/AstraZeneca, DTRM, Genmab, Nurix Javier Pinilla-IbarzHonoraria: Novartis, Pharmacyclics, Janssen, AbbVie, Takeda, AstraZenecaConsulting or Advisory Role: Novartis, Pharmacyclics, Janssen, AbbVieSpeakers' Bureau: Pharmacyclics/Janssen, AbbVie, Takeda, AstraZenecaPatents, Royalties, Other Intellectual Property: From a WT vaccine patent by Memorial Sloan Kettering Cancer Center John F. SeymourHonoraria: AbbVie, Acerta Pharma, Janssen, Roche, Sunesis Pharmaceuticals, TakedaConsulting or Advisory Role: AbbVie, Acerta Pharma, Janssen, Roche, Sunesis Pharmaceuticals, Takeda, AstraZeneca, BMS, Gilead Sciences, MEI Pharma, MorphoSysSpeakers' Bureau: AbbVie, RocheResearch Funding: AbbVie, Celgene, Janssen, RocheExpert Testimony: RocheTravel, Accommodations, Expenses: AbbVie, Roche Stephan StilgenbauerHonoraria: AbbVie, AstraZeneca, Celgene, Gilead Sciences, GlaxoSmithKline, Roche, JanssenConsulting or Advisory Role: AbbVie, AstraZeneca, Celgene, Gilead Sciences, GlaxoSmithKline, Roche, JanssenSpeakers' Bureau: AbbVie, AstraZeneca, Celgene, Gilead Sciences, GlaxoSmithKline, Roche, JanssenResearch Funding: AbbVie, AstraZeneca, Celgene, Gilead Sciences, GlaxoSmithKline, Roche, JanssenTravel, Accommodations, Expenses: AbbVie, AstraZeneca, Celgene, Gilead Sciences, GlaxoSmithKline, Roche, Janssen Tadeusz RobakHonoraria: AbbVieConsulting or Advisory Role: AbbVieResearch Funding: AbbVie/Genentech Wayne RothbaumLeadership: Iovance BiotherapeuticsStock and Other Ownership Interests: Acerta Pharma/AstraZeneca, Telios, Kartos TherapeuticsPatents, Royalties, Other Intellectual Property: Telios Pharma and Kartos TherapeuticsTravel, Accommodations, Expenses: Iovance Biotherapeutics, Kartos TherapeuticsUncompensated Relationships: Kartos Therapeutics, Telios Raquel IzumiEmployment: Acerta Pharma, Vincerx PharmaStock and Other Ownership Interests: Acerta Pharma, Vincerx PharmaPatents, Royalties, Other Intellectual Property: Patents pending for Acerta PharmaExpert Testimony: Diablo Valley Oncology Ahmed HamdyEmployment: Acerta Pharma/AstraZenecaStock and Other Ownership Interests: Acerta PharmaPatents, Royalties, Other Intellectual Property: Acalabrutinib multiple patents Priti PatelEmployment: AstraZeneca, Neoleukin TherapeuticsLeadership: Neoleukin TherapeuticsStock and Other Ownership Interests: AstraZeneca, Neoleukin Therapeutics Kara HigginsEmployment: AstraZeneca, PROMETRIKA LLC Sophia SohoniEmployment: AstraZeneca, Portola PharmaceuticalsStock and Other Ownership Interests: Theravance Wojciech JurczakConsulting or Advisory Role: Janssen-Cilag, Roche, AstraZeneca, Debiopharm Group, EpizymeResearch Funding: Acerta Pharma, TG Therapeutics, Incyte, Bayer, Sandoz-Novartis, Roche, Takeda, Epizyme, Janssen-Cilag, BeiGene, Debiopharm Group, MorphoSys, MEI PharmaNo other potential conflicts of interest were reported.

Bruton tyrosine kinase (BTK) inhibition is an effective therapy for many B-cell malignancies. Acalabrutinib is a next-generation, potent, highly selective, covalent BTK inhibitor. To characterize acalabrutinib tolerability, we pooled safety data from 1040 patients with mature B-cell malignancies treated with acalabrutinib monotherapy in nine clinical studies (treatment-naïve: n = 366 [35%], relapsed/refractory: n = 674 [65%]; median [range] age: 67 [32-90] years; median [range] prior treatments: 1 [0-13]; median [range] duration of exposure: 24.6 [0.0-58.5] months). The most common adverse events (AEs) were headache (38%), diarrhea (37%), upper respiratory tract infection (22%), contusion (22%), nausea (22%), fatigue (21%), and cough (21%). Serious AEs (SAEs) occurred in 39% of patients; pneumonia (6%) was the only SAE that occurred in ≥2%. Deaths due to AEs occurred in 52 patients (5%); pneumonia (n = 8) was the only fatal AE to occur in ≥3 patients. AEs led to treatment discontinuation in 9%. Rates for the AEs of interest (all grades) included infections (67%), hemorrhages (46%), neutropenia (16%), anemia (14%), second primary malignancies (12%), thrombocytopenia (9%), hypertension (8%), and atrial fibrillation (4%). This pooled analysis confirmed acalabrutinib's tolerability and identified no newly emerging late toxicities, supporting acalabrutinib as a long-term treatment for patients with mature B-cell malignancies., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia (CLL), typically to an aggressive lymphoma. Treatment options for RS are limited and the disease is often fatal. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed on CLL cells and other cancers but not on healthy adult tissues, making it an attractive, tumor-specific therapeutic target. VLS-101 is being developed as an antibody-drug conjugate (ADC) for therapy of ROR1-expressing (ROR1+) cancers. VLS-101 comprises UC-961 (a humanized immunoglobulin G1 monoclonal antibody that binds an extracellular epitope of human ROR1), a maleimidocaproyl-valine-citrulline-para-aminobenzoate linker, and the antimicrotubule cytotoxin monomethyl auristatin E (MMAE). VLS-101 binding to ROR1 results in rapid cellular internalization and delivery of MMAE to induce tumor cell death. We studied 4 RS patient-derived xenografts (RS-PDXs) with varying levels of ROR1 expression (11%, 32%, 85%, and 99% of cells). VLS-101 showed no efficacy in the lowest-expressing RS-PDX but induced complete remissions in those with higher levels of ROR1 expression. Responses were maintained during the posttherapy period, particularly after higher VLS-101 doses. In systemic ROR1+ RS-PDXs, VLS-101 dramatically decreased tumor burden in all RS-colonized tissues and significantly prolonged survival. Animals showed no adverse effects or weight loss. Our results confirm ROR1 as a target in RS and demonstrate the therapeutic potential of using an ADC directed toward ROR1 for the treatment of hematological cancers. A phase 1 clinical trial of VLS-101 (NCT03833180) is ongoing in patients with RS and other hematological malignancies., (© 2021 by The American Society of Hematology.)

A small subset of cases of chronic lymphocytic leukemia undergoes transformation to diffuse large B-cell lymphoma, Richter syndrome (RS), which is associated with a poor prognosis. Conventional chemotherapy results in limited responses, underlining the need for novel therapeutic strategies. Here, we investigate the ex vivo and in vivo efficacy of the dual phosphatidylinositol 3-kinase-δ/γ (PI3K-δ/γ) inhibitor duvelisib (Duv) and the Bcl-2 inhibitor venetoclax (Ven) using 4 different RS patient-derived xenograft (PDX) models. Ex vivo exposure of RS cells to Duv, Ven, or their combination results in variable apoptotic responses, in line with the expression levels of target proteins. Although RS1316, IP867/17, and RS9737 cells express PI3K-δ, PI3K-γ, and Bcl-2 and respond to the drugs, RS1050 cells, expressing very low levels of PI3K-γ and lacking Bcl-2, are fully resistant. Moreover, the combination of these drugs is more effective than each agent alone. When tested in vivo, RS1316 and IP867/17 show the best tumor growth inhibition responses, with the Duv/Ven combination leading to complete remission at the end of treatment. The synergistic effect of Duv and Ven relies on the crosstalk between PI3K and apoptotic pathways occurring at the GSK3β level. Indeed, inhibition of PI3K signaling by Duv results in GSK3β activation, leading to ubiquitination and subsequent degradation of both c-Myc and Mcl-1, making RS cells more sensitive to Bcl-2 inhibition by Ven. This work provides, for the first time, a proof of concept of the efficacy of dual targeting of PI3K-δ/γ and Bcl-2 in RS and providing an opening for a Duv/Ven combination for these patients. Clinical studies in aggressive lymphomas, including RS, are under way. This trial was registered at www.clinicaltrials.gov as #NCT03892044., (© 2021 by The American Society of Hematology.)

Acalabrutinib has demonstrated significant efficacy and safety in relapsed chronic lymphocytic leukemia (CLL). Efficacy and safety of acalabrutinib monotherapy were evaluated in a treatment-naive CLL cohort of a single-arm phase 1/2 trial (ACE-CL-001). Adults were eligible for enrollment if chemotherapy was declined or deemed inappropriate due to comorbidities (N = 99). Patients had a median age of 64 years and 47% had Rai stage III/IV disease. Acalabrutinib was administered orally 200 mg once daily, or 100 mg twice daily until progression or intolerance. A total of 99 patients were treated; 57 (62%) had unmutated immunoglobulin heavy-chain variable gene, and 12 (18%) had TP53 aberrations. After median follow-up of 53 months, 85 patients remain on treatment; 14 discontinued treatment, mostly because of adverse events (AEs) (n = 6) or disease progression (n = 3). Overall response rate was 97% (90% partial response; 7% complete response), with similar outcomes among all prognostic subgroups. Because of improved trough BTK occupancy with twice-daily dosing, all patients were transitioned to 100 mg twice daily. Median duration of response (DOR) was not reached; 48-month DOR rate was 97% (95% confidence interval, 90-99). Serious AEs were reported in 38 patients (38%). AEs required discontinuation in 6 patients (6%) because of second primary cancers (n = 4) and infection (n = 2). Grade ≥3 events of special interest included infection (15%), hypertension (11%), bleeding events (3%), and atrial fibrillation (2%). Durable efficacy and long-term safety of acalabrutinib in this trial support its use in clinical management of symptomatic, untreated patients with CLL., (© 2021 by The American Society of Hematology.)

Given advanced age, comorbidities, and immune dysfunction, chronic lymphocytic leukemia (CLL) patients may be at particularly high risk of infection and poor outcomes related to coronavirus disease 2019 (COVID-19). Robust analysis of outcomes for CLL patients, particularly examining effects of baseline characteristics and CLL-directed therapy, is critical to optimally manage CLL patients through this evolving pandemic. CLL patients diagnosed with symptomatic COVID-19 across 43 international centers (n = 198) were included. Hospital admission occurred in 90%. Median age at COVID-19 diagnosis was 70.5 years. Median Cumulative Illness Rating Scale score was 8 (range, 4-32). Thirty-nine percent were treatment naive ("watch and wait"), while 61% had received ≥1 CLL-directed therapy (median, 2; range, 1-8). Ninety patients (45%) were receiving active CLL therapy at COVID-19 diagnosis, most commonly Bruton tyrosine kinase inhibitors (BTKi's; n = 68/90 [76%]). At a median follow-up of 16 days, the overall case fatality rate was 33%, though 25% remain admitted. Watch-and-wait and treated cohorts had similar rates of admission (89% vs 90%), intensive care unit admission (35% vs 36%), intubation (33% vs 25%), and mortality (37% vs 32%). CLL-directed treatment with BTKi's at COVID-19 diagnosis did not impact survival (case fatality rate, 34% vs 35%), though the BTKi was held during the COVID-19 course for most patients. These data suggest that the subgroup of CLL patients admitted with COVID-19, regardless of disease phase or treatment status, are at high risk of death. Future epidemiologic studies are needed to assess severe acute respiratory syndrome coronavirus 2 infection risk, these data should be validated independently, and randomized studies of BTKi's in COVID-19 are needed to provide definitive evidence of benefit.

Purpose: The safety and efficacy of ibrutinib, a once-daily Bruton's tyrosine kinase (BTK) inhibitor, in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) was demonstrated in this phase Ib/II study. Extended follow-up up to 8 years is described, representing the longest follow-up for single-agent ibrutinib, or any BTK inhibitor, to date., Patients and Methods: Phase Ib/II PCYC-1102 (NCT01105247) and extension study PCYC-1103 (NCT01109069) included patients receiving single-agent ibrutinib in first-line or relapsed/refractory CLL/SLL., Results: Overall response rate was 89%, with similar rates in first-line (87%; complete response, 35%) and relapsed/refractory settings (89%; 10%). Estimated 7-year progression-free survival (PFS) rates were 83% in first-line and 34% in relapsed/refractory settings. Forty-one patients had CLL progression ( n = 11 with Richter's transformation). Median PFS was not reached with first-line ibrutinib. In relapsed/refractory CLL/SLL, median PFS was 52 months overall, 26 months in patients with chromosome 17p deletion, 51 months with 11q deletion, not reached with trisomy 12 or 13q deletion, and 88 months in patients without these cytogenetic abnormalities. Estimated 7-year overall survival rates were 84% in first-line and 55% in relapsed/refractory settings. Grade ≥3 adverse events (AE) in >15% of patients were hypertension (28%), pneumonia (24%), and neutropenia (18%). These grade ≥3 AEs generally declined over time, except hypertension. AEs leading to discontinuation in ≥2 patients were observed only in the relapsed/refractory setting (sepsis, diarrhea, subdural hematoma, and Richter's transformation)., Conclusions: With up to 8 years of follow-up, sustained responses and long-term tolerability of single-agent ibrutinib were observed with treatment of first-line or relapsed/refractory CLL/SLL, including high-risk CLL/SLL., (©2020 American Association for Cancer Research.)

Therapeutic targeting of Bruton tyrosine kinase (BTK) has dramatically improved survival outcomes for patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Acalabrutinib is an oral, highly selective BTK inhibitor that allows for twice-daily dosing due to its selectivity. In this phase 1b/2 study, 134 patients with relapsed/refractory CLL or SLL (median age, 66 years [range, 42-85 years]; median prior therapies, 2 [range, 1-13]) received acalabrutinib 100 mg twice daily for a median of 41 months (range, 0.2-58 months). Median trough BTK occupancy at steady state was 97%. Most adverse events (AEs) were mild or moderate, and were most commonly diarrhea (52%) and headache (51%). Grade ≥3 AEs (occurring in ≥5% of patients) were neutropenia (14%), pneumonia (11%), hypertension (7%), anemia (7%), and diarrhea (5%). Atrial fibrillation and major bleeding AEs (all grades) occurred in 7% and 5% of patients, respectively. Most patients (56%) remain on treatment; the primary reasons for discontinuation were progressive disease (21%) and AEs (11%). The overall response rate, including partial response with lymphocytosis, with acalabrutinib was 94%; responses were similar regardless of genomic features (presence of del(11)(q22.3), del(17)(p13.1), complex karyotype, or immunoglobulin variable region heavy chain mutation status). Median duration of response and progression-free survival (PFS) have not been reached; the estimated 45-month PFS was 62% (95% confidence interval, 51% to 71%). BTK mutation was detected in 6 of 9 patients (67%) at relapse. This updated and expanded study confirms the efficacy, durability of response, and long-term safety of acalabrutinib, justifying its further investigation in previously untreated and treated patients with CLL/SLL. This trial was registered at www.clinicaltrials.gov as #NCT02029443., (© 2020 by The American Society of Hematology.)

TP53 alteration in chronic lymphocytic leukemia indicates a high-risk disease that is usually refractory to chemotherapy. It may be caused by deletion of 17p involving the loss of TP53 gene, which occurs in low percentage of patients at diagnosis but can be acquired as the disease progresses. Since patients may harbor TP53 mutation without chromosome 17p deletion, consensus recommendations call for both cytogenetic and PCR mutation analysis of TP53 in chronic lymphocytic leukemia. We conducted a single-institution retrospective study to investigate the clinicopathologic features of chronic lymphocytic leukemia with TP53 alterations as well as the utility of different diagnostic modalities to identify p53 alterations. Forty percent of chronic lymphocytic leukemia patients with TP53 alterations demonstrated atypical lymphocytes with cleaved/irregularly shaped nuclei and/or large atypical lymphoid cells with abundant cytoplasm in the peripheral blood. Progression was also observed in lymph node and bone marrow samples (21% with Richter transformation; 33% with findings suggestive of "accelerated phase" of chronic lymphocytic leukemia including prominent proliferation centers and/or increased numbers of prolymphocytes). However, the presence of the morphologic features suggestive of "accelerated phase" had no effect on overall survival within the chronic lymphocytic leukemia group with TP53 abnormalities (p > 0.05). As previously reported by others, a subset of patients with TP53 alterations were only identified by either PCR mutation analysis (12%) or cytogenetic studies (14%). p53 immunostain positivity was only identified in approximately half of the patients with TP53 alterations identified by either method, and it failed to identify any additional patients with p53 abnormalities. In summary, chronic lymphocytic leukemia patients with TP53 alterations frequently show atypical morphologic features. Use of multiple modalities to identify p53 abnormalities is recommended to ensure optimal sensitivity and specificity.

NOTCH1 mutations in chronic lymphocytic leukemia (CLL) lead to accumulation of NOTCH1 intracellular domain (NICD) and prolong signaling. These mutations associate with a more aggressive disease compared to wild-type (WT) CLL. In this work we demonstrate a bidirectional functional relationship between NOTCH1 and the B cell receptor (BCR) pathways. By using highly homogeneous cohorts of primary CLL cells, activation of NOTCH1 is shown to increase expression of surface IgM, as well as LYN, BTK, and BLNK, ultimately enhancing BCR signaling responses, including global mRNA translation. Upon BCR cross-linking, NOTCH1 itself is actively translated and increased on cell surface. Furthermore, BCR ligation induces calcium mobilization that can facilitate ligand-independent NOTCH1 activation. These data suggest that the two pathways are functionally linked, providing a rationale for dual inhibition strategies. Consistently, addition of the γ-secretase inhibitor DAPT to ibrutinib significantly potentiates its effects, both in vitro and in a short-term patient-derived xenograft model. While this observation may find limited applications in the CLL field, it is more relevant for Richter's Syndrome (RS) management, where very few successful therapeutic options exist. Treatment of RS-patient-derived xenografts (RS-PDX) with the combination of ibrutinib and DAPT decreases disease burden and increases overall survival.

Background: Chemoimmunotherapy is typically the standard of care for patients with Waldenström macroglobulinemia; however, infectious and hematologic toxic effects are problematic. Acalabrutinib is a selective, potent Bruton tyrosine-kinase inhibitor. The aim of this trial was to evaluate the activity and safety of acalabrutinib in patients with Waldenström macroglobulinemia., Methods: This single-arm, multicentre, phase 2 trial was done in 19 European academic centres in France, Italy, Greece, the Netherlands, and the UK, and eight academic centres in the USA. Eligible patients were 18 years or older and had treatment naive (declined or not eligible for chemoimmunotherapy) or relapsed or refractory (at least one previous therapy) Waldenström macroglobulinemia that required treatment, an Eastern Cooperative Oncology Group performance status of 2 or less, and received no previous Bruton tyrosine-kinase inhibitor therapy. Patients received 100 mg oral acalabrutinib twice per day in 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed overall response (at least a minor response) according to the 6th International Workshop for Waldenström Macroglobulinemia (IWWM) and the modified 3rd IWWM workshop criteria. The primary outcome and safety were assessed in all patients who received at least one dose of treatment. This study is registered with ClinicalTrials.gov, number NCT02180724, and is ongoing, but no longer enrolling., Findings: Between Sept 8, 2014, and Dec 24, 2015, 122 patients were assessed for eligibility, of which 106 (87%) patients were given acalabrutinib (14 were treatment naive and 92 had relapsed or refractory disease). With a median follow-up of 27·4 months (IQR 26·0-29·7), 13 (93% [95% CI 66-100]) of 14 treatment naive patients achieved an overall response and 86 (93% [86-98]) of 92 relapsed or refractory patients per both the modified 3rd and 6th IWWM criteria. Seven (50%) of 14 treatment naive patients and 23 (25%) of 92 relapsed or refractory patients discontinued treatment on study. Grade 3-4 adverse events occurring in more than 5% of patients were neutropenia (17 [16%] of 106 patients) and pneumonia (7 [7%]). Grade 3-4 atrial fibrillation occurred in one (1%) patient and grade 3-4 bleeding occurred in three (3%) patients. The most common serious adverse events were lower respiratory tract infection (n=7 [7%]), pneumonia (n=7 [7%]), pyrexia (n=4 [4%]), cellulitis (n=3 [3%]), fall (n=3 [3%]), and sepsis (n=3 [3%]). Pneumonia (n=5 [5%]) and lower respiratory tract infection (n=4 [4%]) were considered treatment related. One treatment-related death was reported (intracranial hematoma)., Interpretation: This study provides evidence that acalabrutinib is active as single-agent therapy with a manageable safety profile in patients with treatment-naive, or relapse or refractory Waldenström macroglobulinemia. Further studies are needed to establish its efficacy against current standard treatments and to investigate whether outcomes can be improved with combination therapies., Funding: Acerta Pharma., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The utility of positron emission tomography-computed tomography (PET-CT) in distinguishing Richter's transformation versus chronic lymphocytic leukemia (CLL) progression after ibrutinib and/or idelalisib was assessed in a post hoc analysis of a phase II study of venetoclax. Patients underwent PET-CT at screening and were not enrolled/treated if Richter's transformation was confirmed pathologically. Of 167 patients screened, 57 met criteria for biopsy after PET-CT. Of 35 patients who underwent biopsy, eight had Richter's transformation, two had another malignancy, and 25 had CLL. A PET-CT maximum standardized uptake value (SUVmax) ≥10 had 71% sensitivity and 50% specificity for detecting Richter's transformation [Odds Ratio (OR): 2.5, 95%CI: 0.4-15; P =0.318]. Response rate to venetoclax was similar for screening SUVmax <10 versus ≥10 (65% vs. 62%) (n=127 enrolled), though median progression-free survival was longer at <10 months (24.7 vs. 15.4 months; P =0.0335). Six patients developed Richter's transformation on venetoclax, of whom two had screening biopsy demonstrating CLL (others did not have a biopsy) and five had screening SUVmax <10. We have defined the test characteristics for PET-CT to distinguish progression of CLL as compared to Richter's transformation when biopsied in patients treated with B-cell receptor signaling pathway inhibitors. Overall diminished sensitivity and specificity as compared to prior reports of patients treated with chemotherapy/chemoimmunotherapy suggest it has diminished ability to discriminate these two diagnoses using a SUVmax ≥10 cutoff. This cutoff did not identify venetoclax-treated patients with an inferior response but may be predictive of inferior progression-free survival. (Registered at clinicaltrials.gov identifier: 02141282 )., (Copyright© 2019 Ferrata Storti Foundation.)