Results of Phase 3 Study of Immunotherapy Prostvac for Advanced Prostate Cancer Due at Year’s End

Results of Phase 3 Study of Immunotherapy Prostvac for Advanced Prostate Cancer Due at Year’s End

Bavarian Nordic announced that full data from its Phase 3 study assessing the effectiveness of its immunotherapy candidate, Prostvac, to improve survival in people with metastatic castration-resistant prostate cancer (mCRPC) is now expected late in 2017, with a third interim analysis likely to be released at mid-year.

The company pushed back the expected release dates based on a decline in the number of average monthly events occurring in patients enrolled in the large-scale trial. “Monthly event rates” measure radiological progression, pain progression, initiation of chemotherapy or death.

“As there has been speculation that the third interim could occur during first quarter of 2017, we believe it is important to update the market on the current estimated timelines,” Paul Chaplin, Bavarian Nordic’s president and chief executive officer, said in a press release.

But, Chaplain added, “We are encouraged that the current monthly event rate has declined. This is great news for the patients. Not only is this consistent with an improvement in the standard of care for patients with mCRPC, which has been observed in recent years, but could also be indicative of a therapeutic effect of PROSTVAC as well.”

Prostvac is a vaccine immunotherapy that targets prostate specific antigen (PSA), which is designed to enhance or stimulate the body’s immune response, particularly T-cells that kill prostate cancer cells.

The current trial, called PROSPECT (NCT01322490), is a randomized, double-blind, and placebo-controlled Phase 3 trial in 1,298 mCRPC patients, with no or minimal symptoms, enrolled at more than 200 sites worldwide. It is evaluating whether Prostvac, alone or in combination with granulocyte macrophage colony-stimulating factor (GM-CSF), is effective in extending overall survival.

GM-CSF is a monomeric glycoprotein that works as a cytokine, a white blood cell growth factor. GM-CSF stimulates stem cells to produce granulocytes and monocytes, which are crucial for fighting infection.

The immunotherapy has been evaluated in 18 ongoing or completed clinical trials, comprising a total of 2,000 participants – 1,100 of whom received active treatment with Prostvac. The therapy has been considered well-tolerated, and a Phase 2 trial showed its potential in extending the median overall survival by 8.5 months in patients with advanced prostate cancer.

The therapy is being developed in cooperation with the National Cancer Institute, under a Cooperative Research and Development Agreement.