Safety and efficacy of acalabrutinib plus bendamustine and rituximab in patients with treatment-naïve or relapsed/refractory mantle cell lymphoma: phase Ib trial.

Tycel Phillips
Michael Wang
Tadeusz Robak
David Gallinson
Don Stevens
Krish Patel, Center for Blood Disorders and Stem Cell Transplantation, Swedish Cancer Institute, Seattle, WA, USA
Safaa Ramadan
Chuan-Chuan Wun
Wojciech Jurczak
Stephen D Smith

Abstract

This multicenter, open-label, phase Ib study (ACE-LY-106) assessed the safety and efficacy of acalabrutinib, bendamustine, and rituximab (ABR) in treatment-naïve (TN) and relapsed or refractory (R/R) mantle cell lymphoma (MCL). Patients received acalabrutinib from cycle 1 until disease progression or treatment discontinuation, bendamustine on days 1 and 2 of each cycle for up to 6 cycles, and rituximab on day 1 of each cycle for 6 cycles, continuing every other cycle from cycle 8 for 12 additional doses (TN cohort). Eighteen patients enrolled in the TN cohort and 20 in the R/R cohort. Median duration of exposure to acalabrutinib was 34.0 and 14.6 months in the TN and R/R cohorts, respectively. No new safety risks were identified, and most adverse events (AE) were grades 1 or 2. Thirteen patients from the TN cohort (72.2%) and 17 patients from the R/R cohort (85.0%) reported grade 3-4 AE, most commonly neutropenia (TN: 38.9%; R/R: 50.0%). AE leading to death were pneumonitis (N=1, TN cohort), COVID-19, and cerebrospinal meningitis (N=1 each, R/R cohort). Overall response was 94.4% and 85.0% in the TN and R/R cohorts, respectively; complete response rates were 77.8% and 70.0%, respectively. After a median follow-up of 47.6 months, median progression-free survival (PFS) and overall survival (OS) were not reached in the TN cohort. After a median follow-up of 20.4 months, median PFS was 28.6 months and OS was not reached in the R/R cohort. Results indicate that ABR was safe and efficacious, supporting further study in patients with TN MCL.