Wang M, Rule S, Zinzani PL, et al. - Given acalabrutinib [a next-generation Bruton tyrosine kinase (BTK) inhibitor] efficacy and safety in relapsed/refractory (R/R) mantle cell lymphoma (MCL) has been shown by initial results in a single-arm phase 2 study (ACE-LY-004), and a long-term analysis at 3-year follow-up revealed consistent safety and efficacy of acalabrutinib and that median overall survival (OS) had not yet been reached, thus, researchers herein report final study outcomes, including updated OS data. Until progressive disease or toxicity, adults with R/R MCL (with no prior BTK/BCL-2 inhibitor exposure) were administered oral acalabrutinib 100 mg twice daily. Analysis involved 124 patients. Following a median observation of 38.1 months at a December 4, 2020 data cutoff for the final analysis, documented overall response rate and complete response remained unaltered since the previous report (81% and 48%). Also, no change was evident in median duration of response and median progression-free survival (29 months and 22 months). Median OS, at the final data cutoff, was reached at 59.2 months. Overall, a high activity of acalabrutinib at a median time on treatment of 17.5 months was corroborated in long-term 3.5-year median follow-up from this study. Findings showed that median OS has been reached at 59 months for R/R MCL cases on acalabrutinib treatment.