Orelabrutinib versus chemoimmunotherapy in treatment-naïve chronic lymphocytic leukemia/small lymphocytic lymphoma: a randomized, phase 3 trial

Orelabrutinib is a potent, irreversible, and highly-selective BTK inhibitor that has been approved for the treatment of relapsed/refractory chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL). This randomized, phase 3 study (ClinicalTrials.gov identifier: NCT04578613) compared orelabrutinib with chemoimmunotherapy in patients with treatment-naïve CLL/SLL. From February 20, 2021, to July 8, 2024, 192 eligible patients were randomly assigned (1:1) to receive either orelabrutinib (91 patients) or chlorambucil plus rituximab (101 patients), comprising the intention-to-treat population. At a median follow-up of 21.4 months (data cutoff, May 17, 2024), the primary endpoint of progression-free survival (PFS) per independent review committee (IRC) was not reached (NR; 95% CI, not estimable [NE]–NE) with orelabrutinib versus 19.4 months (95% CI, 16.6–NE) with chlorambucil plus rituximab (hazard ratio [HR], 0.32; 95% CI, 0.18–0.58; p < 0.0001; crossing the efficacy boundary). The IRC-assessed overall response rate (90.1% vs 79.2%; p = 0.041) and duration of response (HR, 0.30; 95% CI, 0.15–0.60; p = 0.0003) also favored orelabrutinib over chlorambucil plus rituximab. In the safety population, treatment-related adverse events occurred in 82 of 91 patients (90.1%) receiving orelabrutinib and 89 of 98 patients (90.8%) receiving chlorambucil plus rituximab, with 32 (35.2%) and 59 (60.2%) at grade 3 or worse, respectively. Orelabrutinib maintained or improved patient-reported outcomes compared with chemoimmunotherapy. In summary, orelabrutinib significantly improved PFS and response versus chemoimmunotherapy in patients with treatment-naïve CLL/SLL, with a manageable safety profile, supporting it as an effective alternative first-line option.