Matching-adjusted indirect comparison of acalabrutinib versus ibrutinib in relapsed/refractory mantle cell lymphoma

In the absence of head-to-head clinical trials, matching-adjusted indirect comparison (MAIC) was used to compare two Bruton tyrosine kinase inhibitors (BTKis) approved for the treatment of relapsed/refractory (R/R) mantle cell lymphoma (MCL). This analysis compares the efficacy and safety of acalabrutinib versus ibrutinib using a more mature dataset than a previously published MAIC.

Individual patient data from 122 patients treated with acalabrutinib in a phase 2 study were weighted to match aggregate baseline characteristics of patients pooled from three separate trials of ibrutinib. Patients were matched on Eastern Cooperative Oncology Group performance status, simplified Mantle Cell Lymphoma International Prognostic Index, lactate dehydrogenase, prior lines of therapy, tumor burden, and blastoid histology. Outcomes assessed included progression-free survival (PFS), overall survival (OS), and adverse events.

After matching, differences in PFS between acalabrutinib (median = 17.8 months) and ibrutinib (median = 12.8 months) were not statistically significant (hazard ratio [HR] = 0.92; 95% confidence interval [CI] = 0.74-1.15; p = 0.48). Similarly, after matching, OS differences between acalabrutinib (median = 36.5 months) and ibrutinib (median = 27.9 months) did not reach statistical significance (HR = 0.87; 95% CI = 0.64-1.17; p = 0.35). Acalabrutinib was associated with an improved safety profile compared with ibrutinib, with statistically significantly lower rates of grade ≥3 atrial fibrillation and thrombocytopenia.

This comparison of two BTKis used in the treatment of R/R MCL showed that PFS and OS risk was not statistically different between the treatments; however, acalabrutinib had an improved safety profile compared with ibrutinib.