Fixed-duration ibrutinib plus venetoclax for first-line treatment of CLL: primary analysis of the CAPTIVATE FD cohort

: CAPTIVATE (NCT02910583) is an international phase 2 study in patients aged ≤70 years with previously untreated chronic lymphocytic leukemia (CLL). Results from the cohort investigating fixed-duration treatment with ibrutinib plus venetoclax are reported. Patients received 3 cycles of ibrutinib lead-in then 12 cycles of ibrutinib plus venetoclax (oral ibrutinib [420 mg/day]; oral venetoclax [5-week ramp-up to 400 mg/day]). Primary endpoint was complete response (CR) rate. Hypothesis testing was performed for patients without del(17p) with prespecified analyses in all treated patients. Secondary endpoints included undetectable minimal residual disease (uMRD) rates, progression-free survival (PFS), overall survival (OS), and safety. 159 patients were enrolled and treated, including 136 patients without del(17p). Median time on study was 27.9 months and 92% of patients completed all planned treatment. Primary endpoint was met, with CR rate of 56% (95% CI, 48-64) in patients without del(17p), significantly higher than prespecified 37% minimum rate (P<.0001). In the all-treated population, CR rate was 55% (95% CI, 48-63); best uMRD rates were 77% (peripheral blood) and 60% (bone marrow); 24-month PFS and OS rates were 95% and 98%, respectively. At baseline, 21% of patients were in the high tumor burden category for tumor lysis syndrome risk; after ibrutinib lead-in, only 1% remained in this category. Most common grade ≥3 adverse events were neutropenia (33%) and hypertension (6%). First-line ibrutinib plus venetoclax represents the first all-oral, once-daily, chemotherapy-free, fixed-duration regimen for patients with CLL. Fixed-duration ibrutinib plus venetoclax achieved deep, durable responses and promising PFS, including in patients with high-risk features.