The following article features coverage from the American Society of Clinical Oncology 2019 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

The PI3Kδ inhibitor ME-401 achieved a high rate of durable responses in patients with relapsed or refractory follicular lymphoma, according to the results of a phase 1b study presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting. However, more research on the use of a continuous schedule or intermittent schedule of administration will be needed.

The study was designed to test the efficacy of ME-401 in patients with relapsed or refractory B-cell malignancies. Of the 70 treated patients, 48 had follicular lymphoma. Patients were enrolled in a dose-escalation phase examining doses from 60 mg to 180 mg, and then in 60 mg expansion cohorts as monotherapy (39 individuals) or in combination with rituximab (9 individuals).

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ME-401 was given first as a daily continuous schedule until disease progression or unacceptable toxicity, and then evaluated as an intermittent schedule on days 1-7 of a 28-day after 2 cycles (18 patients) or more than or equal to 3 cycles (9 patients). 

With a median follow-up of 9.3 months, 28 patients remained on therapy. Of the 20 patients who discontinued, there were 9 with disease progression, 4 who withdrew because of adverse events, 4 who withdrew consent, and 3 patients who withdrew to undergo stem cell transplant.

Responses were noted in 79% of patients. Similar rates of response were seen in patients assigned monotherapy and those assigned to ME-401 plus rituximab.

Delayed grade 3 immune-related adverse events occurred in about one-third (30%) of patients assigned to the continuous schedule and 11% of patients that switched to the intermittent schedule. Four patients who had grade 3 immune-related adverse events had a break from treatment and were given corticosteroids, but resumed ME-401 on an intermittent schedule with no adverse event recurrence.

Read more of Cancer Therapy Advisor‘s coverage of ASCO’s annual meeting by visiting the conference page.

Reference

Zelentz AD, Jagadeesh D, Reddy NM, et al. Results of the PI3Kδ inhibitor ME-401 alone or with rituximab in relapsed/refractory (R/R) follicular lymphoma (FL). Presented at: 2019 American Society of Clinical Oncology (ASCO) Annual Meeting; May 31-June 3, 2019. Abstract 7512.