FDA Approves First Bispecific Antibody for Follicular Lymphoma

Lunsumio is Genentech’s first approved T-cell engaging bispecific antibody and targets CD20 on the surface of B cells and CD3 on the surface of T cells.

The FDA has granted accelerated approval of Genentech’s Lunsumio (mosunetuzumab-axgb) to treat adult patients with relapsed or refractory (R/R) follicular lymphoma (FL). It is indicated for patients after two or more lines of systemic therapy.

Follicular lymphoma is the most common slow-growing form of non-Hodgkin’s lymphoma, accounting for about one in five cases. It typically responds well to treatment but is often characterized by periods of remission and relapse. In the United States, about 13,000 new cases of FL will be diagnosed in 2022 and more than 100,000 people are diagnosed with FL each year worldwide.

Lunsumio is an off-the shelf bispecific antibody and represents a new class cancer immunotherapy. It targets CD20 on the surface of B cells and CD3 on the surface of T cells. This redirects a patient’s existing T cells to engage and eliminate target B cells.

Lunsumio will be available in the United States in the coming weeks.

“As a first-in-class T-cell engaging bispecific antibody that can be initiated in an outpatient setting, Lunsumio’s high response rates and fixed-duration could change the way advanced follicular lymphoma is treated,” Elizabeth Budde, M.D., Ph.D., said in a press release. She is a hematologic oncologist and associate professor, City of Hope Division of Lymphoma, Department of Hematology & Hematopoietic Cell Transplantation, and Lunsumio clinical trial investigator.

The accelerated approval is based on results from the phase 2 GO29781 study of Lunsumio in people with heavily pretreated follicular lymphoma. Results from the study showed high and durable response rates. An objective response was seen in 80% (72/90) of patients treated with Lunsumio, with a majority maintaining responses for at least 18 months. The objective response rate is the combination of complete response rate (a disappearance of all signs and symptoms of cancer) and partial response rate (a decrease in the amount of cancer in the body. The median duration of response among those who responded was almost two years. A complete response was achieved in 60% of patients (54/90).

Among 218 patients with hematologic malignancies who received Lunsumio, the most common adverse event was cytokine release syndrome. The median duration of cytokine release syndrome events was three days. Other common adverse events included fatigue, rash, pyrexia and headache.

Lunsumio is also investigated as a subcutaneous formulation and in phase 3 studies that will expand the understanding of its impact in earlier lines of treatment in people with non-Hodgkin’s lymphoma.