Evaluating the effectiveness and safety of mosunetuzumab for patients with relapsed/refractory non-Hodgkin lymphoma.

This study investigated the effectiveness and safety of mosunetuzumab (RG7828) for the treatment of patients with relapsed or refractory (r/r) non-Hodgkin lymphoma (NHL). The data showed that mosunetuzumab resulted in long-lasting complete responses with manageable side effects for these patients.

NHL is cancer that starts in white blood cells called lymphocytes, which are part of the body’s immune system. The standard treatment for NHL is chemotherapy plus immunotherapy. A high number of patients with NHL experience relapse (the tumor grows after treatment) or are refractory (not responsive to the treatment) to standard treatment. For these patients, treatment options are limited.

Mosunetuzumab (RG7828) is a new type on immunotherapy. This treatment helps T-cells (an important cell type in the body’s immune system) attack cancer cells. This leads to cancer cell death. However, the effectiveness and safety of mosunetuzumab for the treatment of patients with r/r NHL are still unknown.

The study involved 230 patients with r/r NHL. Patients were divided into 2 groups based on the dose of mosunetuzumab they received. Group 1 included 33 patients who received a fixed dose of mosunetuzumab up to 2.8 mg on day 1. Group 2 included 197 patients who received increasing doses of mosunetuzumab up to 60 mg during cycle 1 on days 1, 8, and 15, with treatment continuing for 8 or 17 cycles based on tumor response. 

In group 2, 34.9% of the patients with aggressive NHL responded to the treatment and 19.4% of the patients achieved a complete response (complete disappearance of cancer). The average length of time that the patients responded to treatment without the cancer growing or spreading was 22.8 months. The average survival without cancer worsening was 1.4 months.

In group 2, 66.2% of the patients with indolent (painless) NHL responded to the treatment and 48.5% of the patients achieved a complete response. The average length of time that the patients responded to treatment without the cancer growing or spreading was 20.4 months. The average survival without cancer worsening was 11.8 months.

In group 2, 27.4% of the patients experienced cytokine release syndrome (CRS). CRS is a side effect of mosunetuzumab caused by the immune system becoming highly active. CRS can cause fever, nausea, skin rash, an increase in heartbeat, low blood pressure, and trouble breathing. The other most common side effects were low white blood cells counts (28.4%), low serum phosphate levels (23.4%), fatigue (22.8%), and diarrhea (21.8%).

This study concluded that mosunetuzumab resulted in long-lasting complete responses with manageable side effects in patients with r/r NHL.

This study was sponsored by Genentech Inc, the manufacturer of mosunetuzumab. Larger studies are needed to fully evaluate the safety and effectiveness of mosunetuzumab.