FDA Issues Special Protocol Assessment Agreement for a Pivotal Phase 3 Clinical Study of a Melanoma Cancer Vaccine

California-based Polynoma LLC today announced that it had reached an agreement with the U.S. Food and Drug Administration (FDA) under a Special Protocol Assessment (SPA) on a pivotal Phase 3 clinical study of seviprotimut-L, Polynoma's melanoma cancer vaccine.

This SPA is for the adjuvant treatment of patients 60 years and younger with Stage IIB or IIC melanoma following definitive surgical resection to improve recurrence-free survival.

Seviprotimut-L previously received Fast Track designation from the U.S. FDA.

The final analysis of Part B1 data from the Melanoma Antigen Vaccine Immunotherapy Study (MAVIS) was recently published in the Journal for ImmunoTherapy of Cancer.

A subgroup analysis of patients receiving seviprotimut-L with AJCC Stage IIB/IIC melanoma, under age 60 with a median follow-up time of 45.8 months (3.8 years), showed clinically significant improvement in recurrence-free survival (RFS), reducing the risk of disease recurrence or death by 68% (HR=0.32; 95% CI, 0.121, 0.864) compared to patients receiving placebo.

Additionally, RFS was more favorable in patients under age 60 with ulcerated melanomas (HR 0.21; 95% CI: 0.065-0.702), and there was a trend toward improved overall survival (HR 0.34; 95% CI: 0.117, 0.975) for patients that received seviprotimut-L compared to those receiving placebo.

There were no immune-mediated AEs, or other treatment-related serious AEs observed.

"Vaccination with seviprotimut- L has an advantage of having very low toxicity, without significant immune-related adverse events and no significant increase in toxicity over placebo," said Craig L. Slingluff, Jr., M.D., Professor of Surgery and Director of the Human Immune Therapy Center and lead author of the JITC research paper on MAVIS, in a press statement issued on January 11, 2022. 

"If the definitive evaluation of this vaccine therapy confirms clinical benefit in patients with Stage IIB/IIC melanoma, particularly those aged 60 and younger, the low toxicity of this approach will be a valuable option for these patients."

Seviprotimut-L is an allogeneic, polyvalent, partially purified shed melanoma antigen vaccine derived from three proprietary human melanoma cell lines. Seviprotimut-L stimulates humoral and cellular immune responses. 

Melanoma-associated antigens (MAAs) found in seviprotimut-L are taken up by antigen-presenting cells (dendritic cells), which then activate the production of antigen-specific cytotoxic T-lymphocytes (CTLs) as well as develop antibody responses against MAAs. 

These CTLs and antibodies then recognize and act on tumor cells expressing the MAAs on their surfaces, causing cell death.

Seviprotimut-L is currently developing for the adjuvant treatment of patients with Stages IIB and IIC melanoma following definitive resection.

Polynoma LLC is a U.S. immuno-oncology focused biopharmaceutical company headquartered in San Diego, CA, and is a wholly-owned subsidiary of CK Life Sciences Int'l., Inc.