Study Finds That Provenge Improves Survival in mCRPC Patients Over Xtandi, Zytiga.

Provenge (sipuleucel-T) by Dendreon Pharmaceuticals, is superior to Zytiga (abiraterone acetate) or Xtandi (enzalutamide) at prolonging the lives of men with metastatic castration (hormone)-resistant prostate cancer (mCRPC) when added at any point in a treatment regimen, according to a real-life study in the U.S.

The study, “A Retrospective Observational Analysis of Overall Survival with Sipuleucel-T in Medicare Beneficiaries Treated for Advanced Prostate Cancer,” was published in the journal Advances in Therapy.

“Men with mCRPC who received [Provenge] had a significant improvement in median overall survival and reduction in the risk of death at three years, regardless of line of use,” according to Rana R. McKay, MD, the study’s lead author at the University of California, San Diego.

“This analysis underscores the importance of using complementary mechanisms of action to maximize patient survival outcomes and highlights the critical role immunotherapy plays in the modern era of mCRPC treatment,” said Bruce A. Brown, MD, Dendreon’s chief medical officer. “Provenge continues to deliver on its promise of helping men with advanced prostate cancer live longer and should be considered when making treatment decisions in daily clinical practice,” Brown added.

Approved in the U.S. in 2010, Provenge is the only immunotherapy that uses a patient’s own immune cells to fight prostate cancer. It consists of an individual’s white blood cells that have been exposed to a prostate cancer protein, ultimately priming them to activate the remaining immune cells to fight cancer.

In the years since Provenge’s approval, the oral agents Zytiga and Xtandi — second-generation androgen-receptor signaling pathway inhibitors (ASPIs) — have become the standard-of-care treatment for men with mCRPC. Currently, both ASPIs and Provenge are recommended as a first-line treatment for the same indication. However, no study to date has compared the effectiveness of Provenge with that of the ASPIs. To fill this knowledge gap, Dendreon researchers and colleagues retrospectively analyzed the survival outcomes of 6,044 men with mCRPC who received either Provenge or ASPIs (Zytiga or Xtandi).

The current study explored differences in the survival outcomes, adjusted for multiple factors available in the dataset that could potentially influence the patients’ risk of death.

The results showed that men treated with first-line Provenge lived significantly longer (34.9 months; nearly three years) than those receiving ASPIs as first-line therapy (21 months; just less than two years), reflecting a 44% reduced risk of death at three years. Further, adding Provenge to either Zytiga or Xtandi at any point of the treatment regimen reduced the risk of death by 41% and prolonged median overall survival by 14.5 months (just over one year). Specifically, overall survival was 35.2 months with any-line Provenge versus 20.7 months without the immunotherapy.

These findings highlight that including Provenge at any point during treatment prolongs the life of men with mCRPC by more than one year and reduces their risk of death by more than 40%.

Moreover, exploratory analyses suggested that patients who received both Provenge and an ASPI during their treatments saw their risk of death reduced by 52% compared with only one ASPI or two sequential ASPIs.

“These findings support the need for further research to explore treatment sequences and therapeutic combinations,” the researchers wrote.

For additional details, see the October 26th issue of Prostate Cancer News Today by Marta Figueiredo.

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