Mosunetuzumab with Polatuzumab Vedotin Triples Remission Time in Relapsed LBCL vs R-GemOx

A new chemotherapy-free combination of mosunetuzumab (Lunsumio, Genentech) and polatuzumab vedotin (Polivy, Genentech) may offer a more effective and better-tolerated option for people with relapsed or refractory large B-cell lymphoma (LBCL) who are not eligible for stem cell transplant. Learn results from the phase 3 SUNMO study and what they could mean as part of your LBCL treatment options.

Designed without traditional chemotherapy 

Mosunetuzumab is a bispecific antibody. It works by attaching to the surface protein CD20 on LBCL cells and CD3 on T-cells. T-cells are a type of white blood cell that are a part of the immune system. They target specific antigens, including cancer cells. Mosunetuzumab helps the T-cells find the cancer cells. 

Polatuzumab vedotin is an antibody-drug conjugate. It pairs an antibody with an anticancer drug. The antibody carries the drug to a specific protein, CD79b, found on LBCL cells. This allows the anticancer drug to target cancer cells while avoiding most healthy cells. 

Without traditional chemotherapy, this combination could reduce chemo-related side effects.

New therapy triples time before cancer worsens

The SUNMO study compared mosunetuzumab with polatuzumab vedotin to a standard chemotherapy combination of rituximab, gemcitabine, and oxaliplatin (R-GemOx).

For patients who took mosunetuzumab with polatuzumab vedotin, the median amount of time the cancer did not progress and patients were alive was 11.5 months, compared to 3.8 months for those who received R-GemOx. These results were also seen in high-risk patients. 

This means the mosunetuzumab with polatuzumab vedotin controlled LBCL nearly three times longer than the standard chemotherapy combination. 

More people responded and stayed in remission longer

In the study, 70.3% of people receiving mosunetuzumab with polatuzumab vedotin saw a partial or full reduction in cancer cells (objective response), compared to 40.0% in the R-GemOx group. Additionally, 51.4% had no detectable LBCL (complete response) versus 24.3% of patients with R-GemOx.  

After one year since achieving a response, nearly 75% of those who had a complete response to the new combination were still in remission, higher than 44.1% in the R-GemOx group. 

For people with relapsed/refractory LBCL, high responses and long-lasting remission are important goals, especially when previous therapies have not worked. 

Encouraging safety profile with potential for outpatient use

The side effects of the mosunetuzumab and polatuzumab vedotin combination were similar to what’s expected from each medicine on its own. The therapy is safe and may be given in an outpatient setting, meaning people can receive treatment without needing to stay in the hospital overnight. 

Cytokine release syndrome, a reaction to immune-based therapy, was seen in about 1 in 4 people and was mostly mild. There were no reports of brain-related side effects (called ICANS). Serious side effects that required hospital-based supportive care were similar between the treatment groups. Only 2.2% of those who received mosunetuzumab and polatuzumab vedotin had to stop treatment due to side effects, compared to 4.7% in the R-GemOx group. 

Possible new option for patients ineligible for transplant 

People with relapsed/refractory LBCL often need second-line treatment. Stem cell transplant is one option, but some patients may not be candidates due to age, health, or other reasons.

Mosunetuzumab with polatuzumab vedotin could be an "off-the-shelf" option, ready to use without delay. That is important when LBCL progresses quickly, and treatment must start immediately. 

FDA review and treatment guidelines

The SUNMO study’s results will soon be submitted to global health authorities, including the U.S. Food and Drug Administration. If approved, this would provide LBCL patients with a new treatment option. 

Mosunetuzumab and polatuzumab vedotin have already been included in specialist guidelines as a second-line treatment for people with diffuse large B-cell lymphoma who are not able to receive a stem cell transplant. This suggests that experts recognize the potential of this combination for future care. 

“There remains a clear need for effective and well-tolerated treatments for people with this difficult-to-treat disease. If approved, this off-the-shelf treatment combination of mosunetuzumab and polatuzumab vedotin could be administered over a fixed period of time, without mandatory hospitalization or traditional chemotherapy, which could provide a meaningful option for patients with relapsed or refractory LBCL.” -Jason Westin, MD, professor of lymphoma and director of lymphoma clinical research at The University of Texas, MD Anderson Cancer Center. 

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Source: 

• Genentech’s Lunsumio and Polivy Combination Significantly Prolongs Remission for People With Relapsed or Refractory Large B-Cell Lymphoma