Six-year follow-up and subgroup analyses of a phase 2 trial of venetoclax for del(17p) chronic lymphocytic leukemia

Chromosome 17p deletion (del[17p]) is associated with poor prognosis in patients with chronic lymphocytic leukemia (CLL). Venetoclax is approved for treatment of previously untreated and relapsed/refractory (R/R) CLL, including patients with del(17p), based on the open-label, multicenter, phase 2 M13-982 trial (NCT01889186). Here, we detail the 6-year follow-up analysis for M13-982. A total of 158 patients with previously untreated (n = 5) or R/R (n = 153) del(17p) CLL received 400 mg venetoclax daily after initial ramp-up until progressive disease. After a median follow-up of 70 months, the best objective response rate (ORR) was 77% (21% complete remission [CR], 49% partial remission [PR]), with a median duration of response (DOR) of 39.3 months (95% confidence interval [CI], 31.1–50.5). The median progression-free survival (PFS) was 28.2 months (95% CI, 23.4–37.6), median overall survival (OS) was 62.5 months (95% CI, 51.7-not reached), with 16% of patients remaining on treatment after 6 years. Multivariable analysis did not identify statistically significant correlation between patient subgroups defined by clinical or laboratory variables and ORR or PFS. The most common grade ≥3 adverse events were neutropenia (42%), infections (33%), anemia (16%), and thrombocytopenia (16%). Post hoc comparative analyses of PFS and OS from treatment initiation, from a 24-month landmark, and by minimal residual disease status were performed between patients with del(17p) in M13-982 and MURANO in the interest of understanding these data in another context. These long-term data show the continued benefits of venetoclax in patients with del(17p) CLL.