Dendreon Pharmaceuticals has completed patient enrollment ahead of schedule in an ongoing Phase 3 trial assessing the safety and efficacy of its immunotherapy Provenge (sipuleucel-T) for men with early-stage prostate cancer on active surveillance, the company announced.

The open-label ProVent trial (NCT03686683) included more than 450 participants from approximately 60 sites across the United States. Patients were randomly assigned to one of two groups: those who continued on active surveillance as standard of care (control group), and those given three infusions of Provenge at approximately two-week intervals.

“The rapid pace of enrollment in the ProVent trial is a significant milestone for Dendreon, and underscores a strong interest by patients and physicians in the potential clinical benefit of sipuleucel-T in men on active surveillance,” Bruce A. Brown, MD, chief medical officer at Dendreon, said in a press release.

Prostate cancer is the most common cancer among men, but a great number of cases will remain dormant and not progress to significant disability or risk of mortality. In these cases, active surveillance — an approach that consists of actively monitoring the cancer to detect progression before starting any treatment — is an accepted alternative to treatments that can carry significant side effects.

Data from large academic institutions and clinical trials have shown that active surveillance is safe and results in low rates of cancer-specific mortality. However, some patients will eventually progress and require radical treatments, such as surgery and radiation.

Provenge is an immunotherapy that uses a patient’s own immune cells to fight prostate cancer. It consists of a fraction of white blood cells that have been exposed to a prostate cancer protein, being primed to trigger the remaining immune cells to fight cancer.

The Phase 3 trial was designed to test Provenge as an alternative to active surveillance for men with early-stage prostate cancer, diagnosed in the past 12 months. Its main goal is to determine if Provenge prevents cancer progression, as assessed by a pathologist. Secondary measures include the percentage of patients who receive subsequent prostate cancer treatment, and the proportion of patients with a negative biopsy (without signs of cancer), and safety.

The study will also evaluate how Provenge affects immune responses and quality of life.

“For men with low-risk, localized prostate cancer, the option of active surveillance is regularly recommended; however, variation in prostate specific antigen (PSA) monitoring and the anxiety of having a ‘cancer’ diagnosis causes many men to leave surveillance management and undergo interventional treatment,” said Neal D. Shore, MD, medical director for the Carolina Urologic Research Center and practicing urologist at Atlantic Urology Clinics.

“Given the numerous studies describing the effectiveness of sipuleucel-T immunotherapy for advanced prostate cancer, we are optimistic that data from ProVent may lead to the first-ever immunotherapy treatment option for men with early-stage prostate cancer,” added Shore, who is also ProVent’s principal investigator.

In 2010, Provenge became the first immunotherapy to be approved in the U.S. for asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer, after data showed that it extended patients’ lives by four months, compared to a placebo. More recent real-world clinical data continues to demonstrate Provenge’s benefits in the same population, with some patients living up to four years after receiving the treatment.

“Provenge has been proven to extend life in men with metastatic castration-resistant prostate cancer (mCRPC), and we intend to change the way prostate cancer is treated by showing that immunotherapy can reduce disease progression and the need for aggressive intervention in men with early-stage disease,” Brown said.