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We report long-term follow-up from the RESONATE-2 phase 3 study of the once-daily Bruton's tyrosine kinase inhibitor ibrutinib, which is the only targeted therapy with significant progression-free survival (PFS) and overall survival (OS) benefit in multiple randomized chronic lymphocytic leukemia (CLL) studies. Patients (≥65 years) with previously untreated CLL, without del(17p), were randomly assigned 1:1 to once-daily ibrutinib 420 mg until disease progression/unacceptable toxicity (n = 136) or chlorambucil 0.5-0.8 mg/kg ≤12 cycles (n = 133). With up to 8 years of follow-up (range, 0.1-96.6 months; median, 82.7 months), significant PFS benefit was sustained for ibrutinib vs chlorambucil (hazard ratio [HR], 0.154; 95% confidence interval [CI], 0.108-0.220). At 7 years, PFS was 59% for ibrutinib vs 9% for chlorambucil. PFS benefit was also observed for ibrutinib- vs chlorambucil-randomized patients with high-risk genomic features: del(11q) (HR, 0.033; 95% CI, 0.010-0.107) or unmutated immunoglobulin heavy chain variable region (HR, 0.112; 95% CI, 0.065-0.192). OS at 7 years was 78% with ibrutinib. Prevalence of adverse events (AEs) was consistent with previous 5-year follow-up. Ibrutinib dosing was held (≥7 days) for 79 patients and reduced for 31 patients because of AEs; these AEs resolved or improved in 85% (67 of 79) and 90% (28 of 31) of patients, respectively. With up to 8 years of follow-up, 42% of patients remain on ibrutinib. Long-term RESONATE-2 data demonstrate sustained benefit with first-line ibrutinib treatment for CLL, including for patients with high-risk genomic features. These trials were registered at www.clinicaltrials.gov as #NCT01722487 and #NCT01724346.

Ibrutinib, a first-in-class once-daily oral Bruton tyrosine kinase inhibitor indicated for chronic lymphocytic leukemia (CLL), is continued until progressive disease or unacceptable toxicity. We conducted an integrated safety analysis of single-agent ibrutinib from randomized phase 3 studies PCYC-1112 (RESONATE, n = 195) and PCYC-1115/1116 (RESONATE-2, n = 135), and examined longer-term safety separately in the phase 1b/2 PCYC-1102/1103 study (n = 94, 420 mg/d). In the integrated analysis (ibrutinib treatment up to 43 months), the most common adverse events (AEs) were primarily grade 1/2; diarrhea (n = 173, 52% any-grade; n = 15, 5% grade 3) and fatigue (n = 119, 36% any-grade; n = 10, 3% grade 3). The most common grade 3/4 AEs were neutropenia (n = 60, 18%) and pneumonia (n = 38, 12%). Over time, prevalence of AEs of interest (diarrhea, fatigue, grade ≥3 infection, bleeding, and neutropenia) trended down; prevalence of hypertension increased, but incidence decreased after year 1. AEs led to dose reductions in 42 (13%) patients and permanent discontinuations in 37 (11%); dose modifications due to AEs were most common during year 1 and decreased in frequency thereafter. The most common AEs (preferred term) contributing to discontinuation included pneumonia (n = 4), anemia (n = 3), and atrial fibrillation (n = 3). With long-term follow-up on PCYC-1102/1103 (ibrutinib treatment up to 67 months), grade 3/4 AEs were generally similar to those in the integrated analysis. Overall, AEs were primarily grade 1/2 and manageable during prolonged ibrutinib treatment in patients with CLL. These trials were registered at www.clinicaltrials.gov as #NCT01578707, #NCT01722487, #NCT01724346, #NCT01105247, and #NCT01109069.

Venetoclax (VEN) is approved for relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) as monotherapy (VENmono) or in combination with rituximab. Whether VEN plus anti-CD20 (VENcombo) is superior to VENmono is unknown. We conducted a multicenter, retrospective cohort analysis comparing 321 CLL patients treated with VENmono vs VENcombo across the United States and the United Kingdom. We examined demographics, baseline characteristics, dosing, adverse events, response rates, and outcomes. The primary endpoints were progression-free survival (PFS) and overall survival (OS), estimated by Kaplan-Meier method, in patients treated with VENmono vs VENcombo. Univariate and bivariate analyses were performed with COX regression. Three hundred twenty-one CLL patients were included (3 median prior treatments, 78% prior ibrutinib). The overall response rates (ORRs) were similar (VENmono, 81% ORR, 34% complete remission [CR] vs VENcombo, 84% ORR, 32% CR). With a median follow-up of 13.4 months, no differences in PFS and OS were observed between the groups. In unadjusted analyses, the hazard ratios (HRs) for PFS and OS for VENmono vs VENcombo were HR 1.0 (95% confidence interval [CI], 0.6-1.8; P = .7) and HR 1.2 (95% CI, 0.6-2.3; P = .5), respectively. When adjusting for differences between the cohorts, the addition of an anti-CD20 antibody in combination with VEN did not impact PFS (HR, 1.0; 95% CI, 0.5-2.0; P = .9) or OS (HR, 1.1; 95% CI, 0.4-2.6; P = .8). We demonstrate comparable efficacy between VENmono and VENcombo in a heavily pretreated, high-risk, retrospective cohort, in terms of both response data and survival outcomes. Prospective studies are needed to validate these findings.