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Introduction: The primary analysis of the phase 3 ECHO trial (NCT02972840) demonstrated that acalabrutinib plus bendamustine-rituximab (ABR) significantly improved progression-free survival (PFS) vs placebo plus bendamustine-rituximab (PBR) in older patients (pts) with previously untreated mantle cell lymphoma (MCL) (Wang et al. EHA 2024, Abstract #LB3439). Here we present additional efficacy and safety results from the ECHO trial. Methods: Pts aged ≥65 years (y) with previously untreated MCL and ECOG PS ≤2 were randomly assigned 1:1 to receive ABR or PBR. Acalabrutinib (100 mg twice daily) or placebo was administered until progressive disease (PD) or unacceptable toxicity. Induction with BR was administered for 6 cycles followed by rituximab maintenance (A±R maintenance, cycles 7-30) in pts achieving a partial or complete response (PR or CR). Pts progressing on PBR could cross over to receive acalabrutinib monotherapy. PFS (primary endpoint) was assessed by independent review committee. Minimal residual disease (MRD) negativity rate (10-5) was assessed in peripheral blood (every 24 weeks [wks], at CR, and at PD) and bone marrow (at CR) by NGS-based ClonoSEQ assay (Adaptive Biotechnologies). Results: Among the 598 pts randomized to ABR or PBR (299 in each arm), high-risk baseline characteristics included high-risk simplified MIPI score in 24.1% and 24.4%, blastoid histology in 8.7% and 6.7%, pleomorphic histology in 5.0% and 6.0%, centrally tested Ki-67 ≥30% in 46.5% and 49.2%, and known TP53 mutation in 7.4% and 9.7%, respectively. PFS hazard ratios (HRs) for subgroups were 0.78 (95% confidence interval [CI] 0.51-1.19) in pts with high-risk simplified MIPI score, 0.68 (95% CI 0.29-1.58) in pts with blastoid histology, 0.64 (95% CI 0.25-1.66) in pts with pleomorphic histology, 0.69 (95% CI 0.49-0.98) in pts with Ki-67 ≥30%, and 0.88 (95% CI 0.42-1.78) in pts with known TP53 mutation. In the ABR arm, median PFS was 22.2 months (mo) among pts who discontinued acalabrutinib during induction for reasons other than PD or death, 29.4 mo in pts who discontinued acalabrutinib during A±R maintenance (cycles 7-30) for reasons other than PD or death, and not reached in pts who received acalabrutinib for 31 cycles or more. Among evaluable patients who were MRD negative at the end of induction (24 wks), the rate of conversion to MRD positive during maintenance was lower in the ABR arm (5.85%; n=11/188) than in the PBR arm (15%; n=26/171). Conversely, among evaluable pts who were MRD positive at the end of induction (24 wks), 37.5% (n=3/8) in the ABR arm and 20% (n=3/15) in the PBR arm converted to MRD negative during maintenance. Overall rates of AEs were similar in each arm during induction, but were higher in ABR during A±R maintenance (cycles 7-30) and more so in the monotherapy phase (cycle 31+). Grade ≥3 TEAEs (ABR vs PBR) were 70.0% vs 68.7% during induction, 64.9% vs 62.9% during A±R maintenance (cycles 7-30), and 57.0% vs 45.3% during monotherapy (cycle 31+). Similarly, rates of TEAEs leading to discontinuation of acalabrutinib/placebo were 8.1% vs 8.8% during induction, 23.9% vs 19.0% during A±R maintenance (cycles 7-30), and 25.9% vs 13.7% during monotherapy (cycle 31+). Exposure-adjusted incidence rates per 100 person-years reduced the difference between ABR and PBR for clinically relevant TEAE rates (32.6 vs 29.3 for grade ≥3 serious TEAEs; 4.2 vs 4.0 for grade 5 TEAEs; 15.5 vs 12.4 for TEAEs leading to acalabrutinib/placebo discontinuation), possibly due to longer median exposure to acalabrutinib (28.6 vs 24.6 mo). Conclusion: Acalabrutinib in combination with BR provides a significant PFS benefit in pts with previously untreated MCL, including those with high-risk features. Furthermore, the addition of acalabrutinib to BR provided a greater PFS effect among pts in the ABR arm with the longest exposure to acalabrutinib. The PFS improvement may be partially driven by the contribution of acalabrutinib to sustained MRD-negative status and deepened responses after the end of induction. ABR provides this clinical benefit without excess toxicity as shown by attenuated differences between arms in exposure-adjusted incidence rates, suggesting that higher AE rates in the ABR arm are likely due in part to the longer duration of acalabrutinib treatment vs placebo. These data emphasize the benefits of acalabrutinib in frontline MCL treatment in high-risk pts and the additional benefit of continuous therapy.

Background and Significance Diffuse large B-cell lymphoma (DLBCL) and other LBCLs account for 35-40% of non-Hodgkin lymphoma cases in North America, Europe, and East Asia. Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), typically administered for 6 cycles, is the standard therapy for DLBCL and is curative in ~60-70% of patients (pts). However, 30-40% of pts have relapsed/refractory (RR) DLBCL following treatment with R-CHOP, with poor clinical outcomes. International Prognostic Index (IPI) scores of 3-5 are used to identify high-risk (HR) pts who are more likely to be RR following treatment. Additionally, pts with IPI scores of 1-2 who also have bulky disease and/or very high lactate dehydrogenase levels (LDH), have been identified as a HR subset with similar outcomes to pts with an IPI score of 3 (Maurer et al. ASH 2023, #4512). First-line therapy represents the greatest opportunity to address the unmet need for these pts. Golcadomide (GOLCA) is a potential first-in-class oral cereblon E3 ligase modulator (CELMoD™) agent purposefully designed for the treatment of lymphoma. GOLCA co-opts cereblon to induce targeted degradation of the transcription factors Ikaros/Aiolos, inducing deep, rapid, and extensive tumor killing, independent of cell of origin, and enhanced immunostimulatory activity. In the phase 1b study CC-220-DLBCL-001, GOLCA combined with R-CHOP was well tolerated, showing promising activity and combinability with high rates of durable responses irrespective of cell of origin in pts with previously untreated aggressive BCL, including those with HR disease (Hoffmann et al. EHA 2024, S235). Additionally, GOLCA has shown encouraging efficacy and safety profiles in pts with RR DLBCL, both as a monotherapy (Michot et al. ICML 2023, P90) and in combination with rituximab (Chavez et al. ASH 2023, P4496). The efficacy and safety data observed in early-phase studies suggest promising activity and a manageable safety profile. This supports further investigation of the GOLCA + R-CHOP combination in the phase 3 setting. Here, we present the study design of GOLSEEK-1, a multicenter, randomized, double-blind, placebo-controlled phase 3 study (NCT06356129) comparing the efficacy and safety of GOLCA + R-CHOP vs placebo + R-CHOP in pts with previously untreated HR LBCL. Study Design and Methods Approximately 850 pts with previously untreated LBCL will be randomized 1:1 to either GOLCA + R-CHOP or placebo + R-CHOP. Pts must have a histologically confirmed diagnosis of LBCL according to WHO 2022 classification, including: DLBCL, not otherwise specified (NOS) including ABC and GCB subtypes; high-grade B-cell lymphoma with MYC and BCL2 rearrangements, or NOS; T-cell/histiocyte-rich LBCL; Epstein-Barr Virus-Positive DLBCL. Other key inclusion criteria include an IPI score of 1 or 2 considered HR (LDH > 1.3 × upper limit of normal and/or bulky disease, defined as a single lesion of ≥ 7 cm [Maurer et al. ASH 2023, #4512]), or IPI score ≥ 3; and measurable disease as defined by the Lugano classification. Key exclusion criteria include other lymphoma subtypes such as primary mediastinal LBCL; primary cutaneous DLBCL-leg type, grade 3b follicular lymphoma (FL); transformed indolent lymphoma; anaplastic lymphoma kinase (ALK)-positive LBCL; primary effusion lymphoma; and Burkitt lymphoma, as well as documented or suspected central nervous system involvement. Randomization will be stratified by IPI score (1-2 with risk factors and 3 vs 4-5) and bulky disease (> 7 cm vs ≤ 7 cm). After a screening period of ≤ 4 weeks, pts will receive GOLCA (0.4 mg) or placebo orally once daily for 7 consecutive days in each of 6 cycles in combination with R-CHOP in 21-day cycles. The primary endpoint of this study is progression-free survival (PFS) in untreated HR LBCL, assessed by investigator based on the Lugano Response Criteria. Key secondary endpoints include PFS in untreated non-high-grade BCL, event-free survival in pts with untreated HR LBCL, independently assessed complete metabolic response rate, undetectable minimal residual disease by PhasED-Seq (defined as undetectable circulating tumor DNA levels at treatment end), and overall survival. Patient follow-up will occur for up to approximately 67 months after beginning treatment. This study is recruiting at 293 sites in 37 countries, across the United States, Europe, Latin America, and East Asia.

7053 Background: In ECHELON-1 (NCT01712490), 6-year follow-up (FU) analyses demonstrated significant improvements in overall survival (OS) and progression-free survival (PFS) with A+AVD (brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine) versus ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine), with a comparable safety profile. Here, we report data at 7-year median FU. Methods: Analyses of OS and PFS per investigator were conducted in the intent-to-treat (ITT) population (data cut-off March 11, 2023). Patients (pts) were randomized 1:1 to receive ≤6 cycles of A+AVD (n=664) or ABVD (n=670) on days 1 and 15, every 28 days. PET scan after cycle 2 (PET2) evaluation was mandatory. Long-term safety outcomes in the safety population included resolution or improvement of peripheral neuropathy (PN), second malignancies, and pregnancies. Results: At median FU of 89.3 months (95% CI 87.0–90.2), 7-year OS rates were 93.5% (95% CI 91.1–95.2) with A+AVD and 88.8% (95% CI 85.8–91.1) with ABVD; OS favored A+AVD over ABVD (HR 0.62; 95% CI 0.42–0.90; p=0.011). Subgroup analyses showed consistent OS benefit for A+AVD, including in the age <40 years and Stage IV disease subgroups (Table). 7-year PFS rates with A+AVD vs ABVD were 82.3% (95% CI 79.1–85.0) vs 74.5% (95% CI 70.8–77.7; HR 0.68 [95% CI 0.53–0.86]; p=0.001). PN improved/resolved in most pts at last FU (A+AVD: 86%; ABVD: 87%). Median (range) time to complete resolution of PN (A+AVD vs ABVD) was 16 (0–373) vs 10 (0–343) weeks; median (range) time to improvement was 42 (2–182) vs 19 (15–142) weeks. PN was ongoing in 28% (4% grade ≥3) of A+AVD and 20% (1% grade ≥3) of ABVD pts. Second malignancies were reported in 5% of A+AVD and 6% of ABVD pts. Pts and their partners reported 84/92 livebirths/pregnancies with A+AVD and 59/73 with ABVD; no stillbirths were recorded. Conclusions: At 7-year median FU, pts with stage III/IV cHL who received A+AVD showed a sustained PFS and OS benefit vs ABVD, with PFS rates indicating potential curability. The safety profile in pts treated with A+AVD showed no new safety signals at 7 years. Clinical trial information: NCT01712490 . [Table: see text]

Background:Richter transformation (RT) occurs in up to 10% of patients with chronic lymphocytic leukemia (CLL), typically presents as an aggressive diffuse large B-cell lymphoma (DLBCL) and is associated with poor survival. RT has no approved standard therapy; and clinical trial enrollment is the preferred first line of therapy. Pirtobrutinib, a highly selective, non-covalent (reversible) BTKi, that inhibits both wildtype and C481-mutant BTK with equal low nM potency, has favorable oral pharmacology that enables continuous BTK inhibition throughout the dosing interval. Pirtobrutinib demonstrated durable overall response rates (ORR) and was well tolerated in patients (pts) with poor-prognosis B-cell malignancies regardless of prior therapy. Here we provide updated safety and efficacy of pirtobrutinib in RT pts from the phase 1/2 BRUIN trial (NCT03740529). Methods: Pts with previously treated, histologically confirmed RT were eligible in the global, multicenter, phase 1/2 BRUIN study. Pts with untreated RT became eligible after Amendment 10. All but one patient received the recommended phase 2 dose of 200 mg daily. Key endpoints included investigator-assessed ORR, DoR per Lugano 2014 criteria, OS, and safety. A data cut of 05 May 2023 was utilized. To assess clonal relationship, IGH rearrangement studies were done on tissue biopsies with RT involvement, and baseline blood or bone marrow (BM) samples with CLL involvement. Results: Among all pts with RT (N=82) the median age was 67 (range, 26-95) and the median total number of lines of prior systemic therapy was 4 (range, 0-13). Pts with prior treatment had a median of 2 CLL-directed therapies and 2 RT-directed therapies. Eight pts did not have a previous line of RT-directed therapy, and 1 patient received neither RT- nor CLL-directed therapy. Common prior RT- and CLL-directed therapies (RT, CLL) included: chemotherapy (76%, 52%), cBTKi (34%, 62%), anti-CD20 antibody (78%, 66%), BCL2i (38%, 49%), stem cell transplant (SCT; 6%, 7%), and CAR-T (11%, 4%). Of 29 pts with bone marrow screening, 41.4% had CLL alone present in BM, 13.8% had DLBCL present and 24.1% had both CLL and DLBCL present. For 39 pts with available PET data, the median SUVmax was 19.1 (range, 2.6-41.2). For all 82 pts, the ORR was 50.0% (95% CI, 38.7-61.3) including complete (13.4%, n=11) and partial (36.6%, n=30) responses. For 61 pts who received prior cBTKi therapy, the ORR was 45.9% (95% CI 33.1-59.2). Among 28 pts with an RT-directed cBTKi and 51 pts with prior CLL-directed cBTKi, the ORR was 42.9% (95% CI, 24.5-62.8) and 43.1% (95% CI, 29.3-57.8), respectively. In 50 pts who discontinued prior cBTKi due to disease progression, the ORR was 42.0% (95% CI, 28.2-56.8). At median follow-up time of 9.7 months, the median DoR for all 82 RT pts was 7.4 months (95% CI, 3.1-19.1) and the estimated rate at 12 months was 45.9% (95% CI, 28.3-61.8). The median time on treatment for the 41pts who responded to treatment was 8.3 months. Eight pts stopped pirtobrutinib to pursue curative-intent allogeneic SCT and DoR was censored at the last preceding disease assessment. At a median survival follow-up of 18.3 months, the median OS for the entire RT cohort was 12.5 months (95% CI, 6.9-20.5). At 18 months, the OS rate was 44.3% (95% CI, 32.5-55.4). Frequent treatment-emergent adverse events (TEAE) in the RT cohort (n=82) were neutropenia/decreased neutrophil count (29.3%, n=24), fatigue (24.4%, n=20) and diarrhea, dyspnea, thrombocytopenia, and pyrexia (18.3% each, n=15). Common grade ≥3 TEAEs were neutropenia/decreased neutrophil count (23.2%, n=19), thrombocytopenia (11.0%, n=9), plus anemia and sepsis (9.8% each, n=8). Any grade hypertension (3.7%, n=3) or atrial fibrillation (1.2%, n=1) were infrequent. Three pts (3.7%) had treatment-related AEs leading to dose reductions, but no pt had a treatment-related AE leading to pirtobrutinib discontinuation. Analyses of clonality will be presented. Conclusions: Continued follow-up from BRUIN demonstrates encouraging response and OS in pts with RT. Pirtobrutinib remains well-tolerated with low rates of discontinuation and manageable safety profile. While RT remains a challenging diagnosis, pirtobrutinib represents a potential treatment option that warrants further investigation.

Introduction Up to 40% of pts with diffuse large B-cell lymphoma (DLBCL) relapse after first-line chemo-immunotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). CELMoD agents such as GOLCA potently degrade target proteins Ikaros/Aiolos, resulting in antiproliferative, apoptotic, and immunomodulatory activity. GOLCA preferentially distributes to tissues and lymphoid organs. In a phase 1 study, GOLCA demonstrated a manageable safety profile with promising clinical activity as monotherapy in relapsed/refractory non-Hodgkin lymphoma (Michot et al. Blood 2021). CC-220-DLBCL-001 (NCT04884035) is an ongoing open-label, multicenter, dose escalation and expansion trial to assess safety and preliminary efficacy of CELMoD agents + R-CHOP for untreated a-BCL. GOLCA demonstrated a manageable safety profile in the dose escalation phase (Munoz et al. ICML 2023 abstract 438); we report combined results from the GOLCA dose escalation and expansion phases. Methods Eligible pts were ≥ 18 years, had untreated a-BCL with measurable disease (Lugano 2014), ECOG performance status ≤ 2 and International Prognostic Index (IPI) score 0-5 (2-5 in dose expansion). Pts were treated with R-CHOP plus GOLCA in 21-day (D) cycles (C) for up to 6C, or until disease progression/unacceptable toxicity/study withdrawal/physician decision. During dose escalation, pts received GOLCA at dose levels (DL): 0.2 mg D1-7 (DL-1), 0.4 mg D1-7 (DL1), and 0.4 mg D1-10 (DL2). DL2 met the dose-limiting toxicity threshold and was not continued in the expansion phase. During dose expansion, pts were randomized 1:1 to R-CHOP plus GOLCA at DL-1 or DL1. The primary endpoint for the expansion phase was safety of GOLCA at the recommended phase 2 dose (DL1) (based on adverse events [AEs]); secondary endpoints included overall response rate (ORR) and complete metabolic response (CMR) rate (assessed at end of treatment [EoT] by PET-CT [Lugano 2014]). Circulating tumor DNA (ctDNA) was measured at C1D1, C2D1, C3D1, and EoT using the PhasED-Seq assay. Results Across escalation and expansion, 78 pts were treated (DL-1, n = 35; DL1, n = 37; DL2, n = 6). Median age was 63.0 years, 56.4% were male, most had high-intermediate/high IPI (3-5) score at diagnosis (64.1%), Ann Arbor stage III-IV disease (83.3%), and germinal center B cell as cell of origin (51.3%); 83.3% pts had DLBCL histology. At data extraction (May 25, 2023), across escalation and expansion, 38 pts had treatment ongoing, 31 completed treatment, and 35 continued to follow-up. A total of 3 pts discontinued due to AEs, 1 each at DL-1, DL1, and DL2. In the safety population (n = 78), median GOLCA relative dose intensity (RDI) was 99.4%; 82.1% of pts received RDI ≥ 85%. RDI for CHOP components was &gt; 90%. A total of 73 (93.6%) pts had ≥ 1 treatment-emergent AE (TEAE); 70 (89.7%) pts had ≥ 1 TEAE considered related to GOLCA; 65 (83.3%) pts had ≥ 1 grade 3/4 TEAE, 62 (79.5%) pts had ≥ 1 grade 3/4 TEAE considered related to GOLCA. The most frequently occurring grade 3/4 TEAEs were neutropenia (76.9%) and thrombocytopenia (32.1%) ( Table). A total of 30 (38.5%) pts had serious TEAEs, most frequently febrile neutropenia (preferred term: 11 pts, 14.1%); 12 (15.4%) pts had serious TEAEs of infection or infestation (system organ class); 6 pts (7.7%) had venous thromboembolisms considered related to GOLCA (4 deep vein thrombosis, 1 superficial thrombosis, 1 pulmonary embolism). Treatment-related AEs leading to GOLCA dose reduction or discontinuation occurred in 11 (14.1%) pts and 6 (7.7%) pts, respectively. After a median follow-up time of 4.1 months (range 0.3-12.3) and among all treated pts with EoT response available, 21/25 had CMR; together, 14/14 pts who received GOLCA 0.4 mg (DL1 and DL2) achieved CMR at EoT ( Figure). Among efficacy-evaluable pts (n = 56), ORR was 91.1% (95% CI 80.4-97.0). Pts treated with GOLCA at DL-1 and DL1 who were ctDNA high-risk (≥ 2.5 log hGE/mL) responded to study treatment (CMR-PMR) and had early decreases in ctDNA (Kaplan et al. ASH 2023). Conclusions GOLCA demonstrated a manageable safety profile, showed good combinability with R-CHOP, and did not compromise delivery of curative treatment. Efficacy results and substantial ctDNA decrease indicate robust clinical activity in frontline DLBCL, with a high CMR rate at EoT, particularly among patients treated at DL1. Study support Bristol Myers Squibb.

Background: Despite the efficacy of covalent (c) Bruton tyrosine kinase inhibitors (BTKi) in R/R MCL, disease relapse arises through evolution of resistance mechanisms or development of cBTKi intolerance. Pirtobrutinib, a highly selective, non-covalent (reversible) BTKi has favorable oral pharmacology that enables continuous BTK inhibition throughout the daily dosing interval regardless of the intrinsic rate of BTK turnover. Pirtobrutinib is the first BTKi to demonstrate durable efficacy following prior cBTKi therapy in heavily pre-treated R/R MCL and was well-tolerated with a low frequency of treatment discontinuation due to toxicity (Wang et al., JCO, 2023). Pirtobrutinib is approved in the USA to treat relapsed or refractory MCL after at least two lines of systemic therapy including a prior cBTKi. Here, we report updated results of pirtobrutinib therapy in all patients (pts), including those with biologically high-risk R/R MCL with a median survival follow-up of 24.2 months (range, 18.2-29.8). Methods: Pts with R/R MCL received pirtobrutinib monotherapy in the multicenter Phase 1/2 BRUIN trial (NCT03740529). Efficacy was assessed in all cBTKi pre-treated pts, as well as in cBTKi treatment-naïve pts. Key endpoints included overall response rate (ORR) as assessed by independent review committee per Lugano 2014 criteria, duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Pts were included across the dose escalation range and expansion (25-300 mg/day) with 93% (n=141) receiving at least one dose of 200 mg/day, the FDA-approved dose. A data cut of 05 May 2023 was utilized. Results: Among all 152 pts with R/R MCL who received a prior cBTKi, the median age was 70 years (range, 46-88), and 52% had intermediate-risk and 28.3% had high-risk sMIPI scores. Median prior lines of therapy were 3 (range, 1-9), including an anti-CD20 antibody (96.7%), chemotherapy (90.1%), immunomodulator (17.1%), stem cell transplant (21.7%), BCL-2 inhibitor (15.8%), CAR-T cell therapy (8.6%), and PI3K inhibitor (3.9%). Among pts with high-risk biomarker data available, 30/60 (50%) had TP53 mutations and 45/63 (71%) had a Ki-67 index of ≥30%. The ORR for cBTKi pre-treated pts was 49.3% (95% CI, 41.1-57.6), including 15.8% complete responses (n=24) and 33.6% partial responses (n=51), whilst cBTKi naïve pts (n=14) had an ORR of 85.7% (95% CI, 57.2-98.2). The ORR among 128 pts who had discontinued a prior cBTKi due to PD and 21 pts who had discontinued for toxicity/other reasons was 43.0% and 90.5%, respectively. Among the 75 responding cBTKi pre-treated pts, the median DOR was 21.6 months (95% CI, 9.2-27.2) at a median follow-up of 24 months. The 18- and 24-month DOR rates were 51.9% (95% CI, 37-64.8) and 38.9% (95% CI, 22.7-54.8), respectively. ORR and DOR by high-risk subgroups (including blastoid/pleomorphic variants, Ki-67 index ≥30%, and TP53 mutations) are shown in Table 1. The 18- and 24-month DOR rates among 12 responding cBTKi naïve pts were both 90.0% (95% CI, 47.3-98.5). The median PFS and OS for cBTKi pre-treated pts was 5.6 months (95% CI, 5.3-9.2), and 23.5 months (95% CI, 17.1-NE), respectively. In the MCL cohort (n=166), the most frequent treatment-emergent adverse events (TEAEs) were fatigue (31.9%), diarrhea (22.3%), and dyspnea (17.5%). The most common Grade ≥3 TEAE was neutropenia/neutrophil count decreased (13.3%) and the rate of Grade ≥3 infections was (19.9%). Grade ≥3 hemorrhage/hematoma (2.4%) and all-grade atrial fibrillation/flutter (3.6%) were infrequent. Overall, 8 pts (5%) had treatment-related AEs leading to dose reductions and 5 (3%) had treatment-related AEs leading to pirtobrutinib discontinuation. Conclusion: Pirtobrutinib continues to demonstrate durable efficacy and a favorable safety profile in heavily pre-treated R/R MCL pts with prior cBTKi therapy. High ORRs were observed in pts who had PD on a prior cBTKi, and in pts with high-risk disease features including blastoid/pleomorphic variants, elevated Ki-67 index, and TP53 mutations.

Abstract 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.