Phase I/II Study of Sonrotoclax (BGB-11417) Monotherapy in Patients With Mantle Cell Lymphoma Previously Treated With Anti-CD20 Therapy and a Bruton Tyrosine Kinase Inhibitor

Abstract

PURPOSE Mantle cell lymphoma (MCL) is a rare and typically aggressive B-cell non-Hodgkin lymphoma characterized by recurrent relapse after short remissions. Sonrotoclax (BGB-11417) is a next-generation B-cell lymphoma 2 inhibitor with greater selectivity and potency than venetoclax, a shorter half-life, and no drug accumulation. Sonrotoclax monotherapy was evaluated in Bruton tyrosine kinase inhibitor–pretreated patients with relapsed/refractory (R/R) MCL. METHODS BGB-11417-201 (ClinicalTrials.gov identifier: NCT05471843 ) is an ongoing global, open-label, phase I/II trial. Sonrotoclax was orally administered once daily with gradual, 4-week ramp-up to 160 mg or 320 mg to mitigate tumor lysis syndrome (TLS). The primary end point was overall response rate by the independent review committee (ORR-IRC) per Lugano classification; secondary end points included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS Overall, 125 patients were enrolled and assigned to receive sonrotoclax 160 mg (n = 10) or 320 mg (n = 115) target doses once daily. Most patients had advanced disease (stage IV, 78.3%) and were heavily pretreated (median prior therapies, 3). In efficacy-evaluable patients (n = 103), the ORR-IRC was 52.4% (95% CI, 42.4 to 62.4), a statistically significant increase versus the historic control ORR (30%; P < .0001); the complete response rate was 15.5%. Responses were seen across high-risk subgroups, including patients with TP53 mutation (59.1%). With a median study follow-up of 14.2 months, the median DOR-IRC was 15.8 months, and the median PFS-IRC was 6.5 months. Median OS was not reached. The most common all-grade/grade ≥3 treatment-emergent adverse events were neutropenia (35.7%/19.1%), thrombocytopenia (24.3%/9.6%), and anemia (24.3%/7.8%). TLS occurred in 7.0% of patients; all cases resolved without sequelae. CONCLUSION Sonrotoclax demonstrated rapid, durable responses and manageable safety in heavily pretreated patients with R/R MCL, including high-risk subgroups, supporting its further clinical evaluation as an oral therapy for R/R MCL.