Efficacy of pirtobrutinib in covalent BTK-inhibitor pre-treated relapsed/refractory CLL/SLL: Additional patients and extended follow-up from the phase 1/2 BRUIN study

Pirtobrutinib remains a strong clinical area of interest as a noncovalent BTK inhibitor for patients with CLL who have experienced disease progression during prior covalent BTK inhibitor therapy. Researchers demonstrated that in a heavily pretreated population (including many patients who had received chemoimmunotherapy, BCL2 inhibitors, and anti-CD20 antibodies), the ORR with pirtobrutinib was 74%. At a median follow up of 13.9 months, the median PFS was 19.4 months (95% CI, 16.6 – 22.3 months). The most common treatment-related adverse events (TRAE) of any grade included fatigue, diarrhea, and contusion; the most common grade > 3 TRAE was neutropenia. Additional adverse events of interest based on prior data for covalent BTK inhibitors included relatively low rates of grade > 3 AEs including hypertension (3%), hemorrhage (2%), and atrial fibrillation/flutter (1%), with only 2% of patients discontinuing therapy due to treatment related side effects.