Dr Phillips on the Implications of the FDA Approval of Pirtobrutinib in R/R Mantle Cell Lymphoma

Tycel Phillips, MD, MPH, associate clinical professor, Division of Lymphoma, Department of Hematology & Hematopoietic Cell Transplantation, City of Hope, discusses the implications of the FDA approval of pirtobrutinib (Jaypirca) in patients with relapsed/refractory mantle cell lymphoma (MCL).

In January 2023, the regulatory agency granted accelerated approval to pirtobrutinib for the treatment of adult patients with relapsed or refractory MCL following at least 2 lines of systemic therapy, including a BTK inhibitor, based on data from a subset of patients enrolled to the open-label, single-arm phase 1/2 BRUIN trial (NCT03740529).

Findings showed that patients treated with pirtobrutinib at a daily dose of 200 mg (n = 120) experienced an overall response rate of 50% (95% CI, 41%-59%), including a complete response rate of 13% and a partial response rate of 38%. Additionally, the median time to response was 1.8 months (range, 0.8-4.2) and the median duration of response (DOR) was 8.3 months (95% CI, 5.7–not evaluable). The estimated 6-month DOR rate was 65.3% (95% CI, 49.8%-77.1%).

The approval has provided another treatment option for patients with relapsed/refractory MCL who have progressed following treatment with a covalent BTK inhibitor, Phillips says. However, long-term data on pirtobrutinib still need to be gathered and analyzed, especially as the agent more widely enters clinical practice, he adds. The expanded use will provide real-world data on how the drug affecting patients who are refractory to the covalent BTK inhibitors, Phillips explains.

In the short term, pirtobrutinib could also serve as a bridge to more definitive treatments, such as CAR T-cell therapy with brexucabtagene autoleucel (Tecartus; formerly KTE-X19). If the patients have a good response, allogeneic stem cell transplant could also be an option, Phillips continues. With limited options currently available for patients who progress on a covalent BTK inhibitor, pirtobrutinib serves as a potential treatment for patients who may not be able to access CAR T-cell therapy, Phillips concludes.