Sustained Benefit of Zanubrutinib vs Ibrutinib in Patients With R/R CLL/SLL: Final Comparative Analysis of ALPINE

ALPINE (NCT03734016) established the superiority of zanubrutinib over ibrutinib in patients with relapsed/refractory chronic lymphocytic leukemia and small lymphocytic lymphoma (R/R CLL/SLL); here we present data from the final comparative analysis with extended follow-up. Overall, 652 patients received zanubrutinib (n=327) or ibrutinib (n=325). At an overall median follow-up of 42.5 months, progression-free survival benefit with zanubrutinib vs ibrutinib was sustained (HR: 0.68 [95% CI, 0.54-0.84]), including in patients with del(17p)/TP53 mutation (HR: 0.51 [95% CI, 0.33-0.78]) and across multiple sensitivity analyses. Overall response rate remained higher with zanubrutinib compared with ibrutinib (85.6% vs 75.4%); responses deepened over time with complete response/complete response with incomplete bone marrow recovery rates of 11.6% (zanubrutinib) and 7.7% (ibrutinib). While median overall survival has not been reached in either treatment group, fewer zanubrutinib patients have died than ibrutinib patients (HR: 0.77 [95% CI, 0.55-1.06]). With median exposure time of 41.2 and 37.8 months in zanubrutinib and ibrutinib arms, respectively, the most common non-hematologic adverse events included COVID-19-related infection (46.0% vs 33.3%), diarrhea (18.8% vs 25.6%), upper respiratory tract infection (29.3% vs 19.8%), and hypertension (27.2% vs 25.3%). Cardiac events were lower with zanubrutinib (25.9% vs 35.5%) despite similar rates of hypertension. Incidence of atrial fibrillation/flutter was lower with zanubrutinib vs ibrutinib (7.1% vs 17.0%); no cardiac deaths were reported with zanubrutinib vs six cardiac deaths with ibrutinib. This analysis, at 42.5 months median follow-up, demonstrates that zanubrutinib remains more efficacious than ibrutinib with an improved overall safety/tolerability profile.