Researchers at the ASH Annual Meeting and Exposition reported high response rates in patients with relapsed peripheral T-cell lymphoma after treatment with single-agent duvelisib, a dual PI3K inhibitor.1
Barbara Pro, MD, of Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, reported the updated results of the phase II PRIMO dose-optimization trial of duvelisib in relapsed or refractory PTCL. Consistent responses were shown across a variety of subtypes.
“Duvelisib is one of the most effective agents in PTCL and hopefully will be approved and become available soon for treatment. The next question will be how to move this agent upfront,” Dr. Pro said.
Duvelisib is a dual PI3K inhibitor approved for relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma and follicular lymphoma. It showed encouraging activity as monotherapy in a phase I study of relapsed/refractory PTCL and cutaneous TCL.
Barbara Pro, MD
The PRIMO dose optimization cohort included 33 patients treated with 25 mg or 75 mg twice daily. Response rates by independent review were 40% and 62%, respectively. The median duration of response was 12.2 months with 75 mg twice daily, Dr. Pro reported.
Based on these initial results, the researchers next treated patients in the dose-expansion phase with 75 mg twice daily for two cycles to achieve tumor control, then with 25 mg twice daily to maintain long-term disease control. Using this schema, 25 patients were treated, 52% responded, and 36% achieved complete responses. The median duration of response was 4.1 months, but follow-up is short (median = 3.8 months), she acknowledged.
The adverse events profile to date has been consistent with what was previously observed with duvelisib, with no unexpected toxicities. Serious adverse events thought to be related to duvelisib were pneumonitis and, in one patient, both posttransplant lymphoproliferative disorder and a skin lesion. One pneumonitis event and two cases of elevated liver enzymes led to treatment discontinuation.
“Monotherapy with duvelisib shows consistent response rates across the most common histologic subtypes in patients with relapsed or refractory PTCL,” Dr Pro said. “Enrollment for the dose-expansion phase is ongoing and is expected to conclude at the beginning of next year.”
DISCLOSURE: Dr. Pro has received honoraria from Celgene, Kiowa, Portola Pharmaceuticals, Seattle Genetics, and Takeda; has served in a consulting or advisory role for Corvus Pharmaceuticals; has received research funding from Verastem; has received institutional research funding from Celgene and Takeda; and has been reimbursed for travel, accommodations, or other expenses by Seattle Genetics and Takeda.
REFERENCE
1. Pro B, Brammer JE, Casulo C, et al: Duvelisib in patients with relapsed/refractory peripheral T-cell lymphoma from the phase 2 PRIMO trial: Dose optimization efficacy update and expansion phase initial results. 2020 ASH Annual Meeting & Exposition. Abstract 44. Presented December 5, 2020.
