Dr. Thompson on the Safety Profile of Pirtobrutinib in Patients With Richter Transformation

Meghan Thompson, MD, third-year fellow, Hematology and Medical Oncology, Memorial Sloan Kettering Cancer Center, discusses the safety profile of pirtobrutinib (LOXO-305) in patients with Richter transformation.

Findings from the phase 1/2 BRUIN study (NCT03740529) demonstrated a 67% overall response rate with pirtobrutinib, a noncovalent, oral BTK inhibitor, among 15 evaluable patients with Richter transformation.

Regarding safety, pirtobrutinib was well tolerated among patients, and toxicities were generally consistent with those observed in the overall patient population, which included patients with previously treated, advanced B-cell malignancies. In the Richter transformation cohort, the most common treatment-emergent adverse effects included neutrophil count decrease and diarrhea.

Notably, none of the 17 patients with Richter transformation discontinued pirtobrutinib because of toxicity. A dose reduction of pirtobrutinib from 200 mg daily to 100 mg daily was required in 1 patient because of toxicity, Thompson concludes.