FDA Grants Priority Review to Mosunetuzumab for Relapsed or Refractory Follicular Lymphoma

Clinical trial results show durable responses with mosunetuzumab in advanced follicular lymphoma.

The FDA has granted priority review to a Biologics License Application (BLA) for mosunetuzumab (Genentech) for the treatment of adults with relapsed or refractory (R/R) follicular lymphoma (FL) who were previously administered at least 2 systemic therapies.

The FDA is expected to make a decision on the potential first-in-class CD20xCD3 T-cell engaging, fully humanized immunoglobulin G1 bispecific antibody immunotherapy by December 29, 2022, according to Genentech. FL is the most common indolent form of non-Hodgkin lymphoma (NHL), which often recurs following initial therapy, with periods of remission and relapse. An estimated 13,000 new cases of FL will be diagnosed in the United States in 2022.

“New therapeutic options are needed for follicular lymphoma, which often relapses after initial therapy and becomes increasingly difficult to treat each time it returns. Clinical trial results have demonstrated durable responses with mosunetuzumab in advanced follicular lymphoma, representing a step toward shifting the treatment paradigm,” said Levi Garraway, MD, PhD, chief medical officer and head of Global Product Development, in a press release. “Since mosunetuzumab does not require the collection or genetic modification of patient cells, it could become an effective, fixed-duration outpatient option without the barriers of travelling to a major academic center.”

The BLA submission followed positive results from the phase 1/2 GO29781 study, in which mosunetuzumab showed high complete response (CR) rates, as most responders (57% [95% CI: 49-70]) maintained their responses for at least 18 months, with manageable tolerability in patients with heavily pretreated FL.

At a median follow-up of 18.3 months, the CR rate was 60% (n=54/90), the objective response rate was 80% (n=72/90), and the median duration of response among patients who responded to treatment was 22.8 months (95% CI: 9.7-not estimable).

The most common adverse event was cytokine release syndrome (39%; n=86/218)—which was typically low grade (grade 1: 25.6%; grade 2: 14%; grade 3: 2.3%; grade 4: 0.5%), and all of which resolved—followed by (>20%) fatigue, headache, neutropenia, fever, and hypophosphatemia.

Mosunetuzumab was previously awarded FDA Breakthrough Therapy Designation in June 2020 for adults with R/R FL previously administered at least 2 systemic therapies, as well as Orphan Drug Designation in December 2018.

Mosunetuzumab is designed to target CD20 on the surface of B cells and CD3 on the surface of T cells, which activates and redirects T cells to engage and kill target B cells by releasing cytotoxic proteins into the B cells. Mosunetuzumab is being investigated as a monotherapy and in combination with other medicines, for the treatment of B-cell non-Hodgkin lymphomas, including follicular lymphoma, diffuse large B-cell lymphoma, and other blood cancers.

Reference

FDA Grants Priority Review to Genentech’s Mosunetuzumab for People with Relapsed or Refractory Follicular Lymphoma. Genentech. News release. July 6, 2022. https://www.gene.com/media/press-releases/14958/2022-07-05/fda-grants-priority-review-to-genentechs