Prolonged progression-free survival with zanubrutinib in relapsed/refractory CLL: an indirect treatment comparison...

Bruton tyrosine kinase inhibitors (BTKis) are therapeutic agents for relapsed/refractory chronic lymphocytic leukemia (R/R CLL). Previous indirect treatment comparisons are limited in simultaneously comparing multiple interventions and adjusting for population differences. This study aimed to use a more rigorous approach called multilevel network meta-regression (ML-NMR) to estimate the relative treatment effects of zanubrutinib compared to acalabrutinib and ibrutinib in two target populations: a general R/R CLL population similar to the phase 3 ALPINE trial's intention-to-treat (ITT) population, and a high-risk population with del(17p) and/or del(11q), similar to the ITT population of the phase 3 ELEVATE-RR trial.

The ML-NMR was conducted using data from three phase 3 randomized controlled trials: ALPINE (N = 652), ELEVATE-RR (N = 533), and ASCEND (N = 310). Progression-free survival (PFS) and overall survival (OS) were the outcomes of interest. The ML-NMR integrated individual patient data from ALPINE with aggregate data from the other trials, incorporating important effect modifiers to estimate relative treatment effects for the target populations.

In the general R/R CLL population, zanubrutinib showed an improved PFS compared to ibrutinib (HR = 0.67, 95% Credible Interval [CrI] = 0.52-0.87) and acalabrutinib (HR = 0.57, 95% CrI = 0.34-0.95). In the high-risk population, zanubrutinib maintained its PFS advantage over ibrutinib and acalabrutinib. OS was similar across BTKis in both populations, with wide CrIs that included an estimate of no difference between treatments.

This ML-NMR suggests that zanubrutinib offers improved PFS compared to ibrutinib and acalabrutinib in both general and high-risk R/R CLL populations. OS results were uncertain due to limited follow-up.