CHRONOS-4: phase 3 study of copanlisib plus rituximab-based immunochemotherapy in relapsed indolent B-cell lymphoma

Copanlisib, a pan-class I phosphatidylinositol 3-kinase inhibitor with predominant activity against the α and δ isoforms, previously demonstrated durable responses as monotherapy and improved progression-free survival (PFS) in combination with rituximab in patients with relapsed indolent non-Hodgkin lymphoma (iNHL). CHRONOS-4 was a phase 3, randomized, double-blind, placebo-controlled study to investigate the efficacy and safety of copanlisib in combination with standard immunochemotherapy in patients with relapsed iNHL. Patients (n = 524) were randomized (1:1) to copanlisib (60 mg IV) plus immunochemotherapy (rituximab and bendamustine [R-B] or placebo plus R-B). Copanlisib/placebo were administered with R-B (days 1, 8, and 15 of each 28-day cycle) for ≤6 cycles and as monotherapy from cycle 7 up to 12 months. The primary study end point was PFS. Median exposure was 8.5 months (0.2-12.9) for copanlisib plus R-B and 11.4 months (0.1-12.6) for placebo plus R-B. Median PFS was 32.9 months (95% confidence interval [CI], 24.4-38.6) for copanlisib plus R-B and 33.3 months (95% CI, 27.8-42.8) for placebo plus R-B (hazard ratio, 1.13; 95% CI, 0.88-1.44; P = .83). No differences between treatment arms were observed in overall survival (data not yet mature), objective response rate, and duration of response for the overall population or individual histology types. Overall, copanlisib plus R-B was associated with higher rates of serious treatment-emergent adverse events (TEAEs), grade 4 and 5 TEAEs, and treatment discontinuation. A number of serious TEAEs were infections. Overall, copanlisib plus R-B did not provide clinical benefit vs placebo plus R-B and was associated with worse tolerability in patients with relapsed iNHL. This trial was registered at www.ClinicalTrials.gov as #NCT02626455.