Updated results of a study looking at the dose optimization of duvelisib in patients with relapsed/refractory peripheral T-cell lymphoma (PTCL) from the PRIMO trial support continued evaluation of the drug in this patient population.

Barbara Pro, MD, of Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, presented the mature dose-optimization results and initial results of dose expansion at the virtual 62nd American Society of Hematology (ASH) Annual Meeting and Exposition.

The phase 2 PRIMO trial (ClinicalTrials.gov Identifier: NCT03372057) had a dose-optimization phase that included patients who had received 2 or more cycles of a single prior regimen.

Initial results of the dose-optimization phase showed an overall response rate (ORR) of 54% for the 75 mg twice-daily dose and 35% in the 25 mg twice-daily dose. The median duration of response was 12.2 months with the 75-mg twice-daily dose. All early dropouts for disease progression were on the 25-mg dose.


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Based on initial results, the researchers determined patients would receive the 75-mg twice-daily dose for 2 cycles to get rapid tumor control followed by 25 mg twice daily to maintain long-term disease control.

Twenty-five patients have been dosed in the dose-expansion phase; 13 have responded. The ORR was 52% with a complete response rate of 36%. The median duration of response was 4.1 months, but follow-up is short at this point, Dr Pro noted.

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 the study drug were pneumonitis, posttransplant lymphoproliferative disorder, and a skin lesion. One pneumonitis event and 2 AST/ALT increase events led to treatment discontinuation.

“Monotherapy with duvelisib shows consistent response rates across the most common histologic subtypes in patients with relapsed refractory PTCL,” Dr Pro said. “Enrollment for the dose-expansion phase is ongoing and is expected to conclude at the beginning of next year.”

Disclosures: Some of the presenters disclosed financial relationships with the pharmaceutical industry and/or the medical device industry. For a full list of disclosures, please refer to the presentation abstract.

Reference

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. Presented at: the 62nd American Society of Hematology (ASH) Annual Meeting and Exposition; December 5-8, 2020. Abstract 44.

This article originally appeared on Cancer Therapy Advisor