Phase 3 Study of Prostvac in Castration-resistant Prostate Cancer Discontinued

Phase 3 Study of Prostvac in Castration-resistant Prostate Cancer Discontinued

An independent Data Monitoring Committee (DMC) recommended that the Phase 3 PROSPECT study of Prostvac in men with metastatic castration-resistant prostate cancer (mCRPC) should be discontinued due to inadequate results.

Prostvac is produced by Bavarian Nordic. In a press release sent out from the pharmaceutical company on Sept. 14, Bavarian Nordic’s president and CEO Paul Chaplin said, “We are extremely disappointed for patients that this study of Prostvac as monotherapy was not successful.”

“On behalf of Bavarian Nordic, I want to express our gratitude to the PROSPECT investigators, patients and families who participated in this trial,” he added.

The PROSPECT trial (NCT01322490) was a randomized, double-blind, and placebo-controlled Phase 3 trial that included 1,298 mCRPC patients from 200 sites in 15 countries. These men had minimal or no symptoms associated with their mCRPC.

The trial evaluated whether Prostvac, alone or in combination with granulocyte macrophage colony-stimulating factor (GM-CSF), could improve overall survival compared to a placebo.

GM-CSF is a cytokine or signaling molecule that can also stimulate the immune system. It stimulates the production of granulocytes and monocytes, two types of cells in the immune system that are important for fighting infections.

Prostvac is a vaccine immunotherapy that specifically targets prostate specific antigen (PSA). It is designed to enhance or stimulate the body’s immune system to kill PSA-positive prostate cancer cells. Prostvac is being developed in collaboration with the National Cancer Institute under a Cooperative Research and Development Agreement.

Previous studies evaluating more than 2,000 participants suggested that Prostvac immunotherapy was well-tolerated. In a Phase 2 trial, this immunotherapy showed potential in prolonging survival in men with advanced prostate cancer. However, the interim analysis for the Phase 3 PROSPECT trial suggested that Prostvac may not be as effective as hoped.

Bavarian Nordic is a biotech company that focuses on the development, manufacturing, and commercialization of cancer immunotherapies as well as vaccines for infectious diseases.

Although the PROSPECT trial was not successful, Chaplin remains positive.

“While this is certainly not the desired outcome, we remain steadfast believers in the power of combination treatments, including immunotherapies, to transform the future of cancer therapies,” he said.