In this ongoing study, patients with untreated chronic lymphocytic leukemia (CLL) received sonrotoclax (an investigational BCL2 inhibitor) plus obinutuzumab. The combination was generally safe, with no deaths or treatment discontinuations due to side effects. The most common any-grade treatment-emergent adverse events (TEAEs) were thrombocytopenia, infusion-related reaction, and neutropenia. No laboratory or clinical tumor lysis syndrome (TLS) events occurred during sonrotoclax ramp-up. High rates of deep remission (undetectable minimal residual disease) were achieved early and maintained over time. The findings support further research into this combination, which is now being studied in the larger phase 3 CELESTIAL-RRCLL (BGB-11417-303) trial.