Ibrutinib with Venetoclax in Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia: A Phase II Study

We explored the efficacy of the combination of ibrutinib + venetoclax in patients with relapsed and/or refractory (R/R) chronic lymphocytic leukemia (CLL). This phase II study enrolled 80 patients between July 2016 and September 2018. Patients received ibrutinib for the first 3 cycles, followed by ibrutinib + venetoclax for 24 cycles. Of the 79 treated patients, the median age was 61 years (IQR, 56-69); 65 (65/76, 86%) had unmutated IGHV and 29 (37%) had either del(17p) or a TP53 mutation. The median number of prior treatments was 1 (range, 1-3). The primary endpoint, best complete remission (CR) and CR with incomplete count recovery (CRi), was 67%, with a bone marrow undetectable measurable residual disease [10-4 sensitivity (U-MRD4)] rate of 61%. At 95.5 months of median follow-up, the estimated 7-year progression-free survival rate was 63.3%. Grade ≥3 neutropenia and thrombocytopenia occurred in 38% and 13% of patients, respectively. The 24-cycle ibrutinib + venetoclax combination led to high rates of CR/CRi and bone marrow U-MRD4 in patients with R/R CLL. SIGNIFICANCE: The 24-cycle ibrutinib + venetoclax combination led to high rates of CR/CRi and bone marrow U-MRD4 in patients with R/R CLL. Responses were durable, including in patients with high-risk genomics.