Outcomes following ibrutinib to zanubrutinib transition in Waldenström macroglobulinemia

A study evaluating outcomes in 47 patients with Waldenström macroglobulinemia (WM) transitioning from ibrutinib treatment in the phase III ASPEN trial (NCT03053440) to zanubrutinib in the long-term extension 1 (LTE1) study (NCT04170283) was published by Garcia-Sanz et al. in Blood Advances. The primary outcome was safety.

Key data: At a median follow-up of 15.3 months, 85% of patients remained on zanubrutinib treatment in LTE1. Most ibrutinib treatment-emergent adverse events (TEAEs) of interest for Bruton’s tyrosine kinase (BTK) inhibitors did not recur or worsen with zanubrutinib. In LTE1, Grade ≥3 and serious TEAEs occurred in 23.4% and 12.8% of patients, respectively. No new episodes of hypertension occurred, and no resolved or ongoing atrial fibrillation/flutter recurred or worsened. The best overall response (BOR) was observed in 96% (44/46) of patients. 

Key learning: The findings demonstrate that patients with WM who tolerated ibrutinib may safely transition to zanubrutinib without compromising efficacy.