Ipilimumab and radiotherapy improves survival in patients with metastatic castration-resistant prostate cancer

This trial was carried out to examine the effectiveness of radiotherapy followed by treatment with ipilimumab (Yervoy) in men with metastatic castrate-resistant prostate cancer  (mCRPC). The trial found that this treatment led to higher survival in these patients compared to radiotherapy followed by placebo.

Prostate cancer (PC) is one of the most common forms of cancer found in men. mCRPC is a form PC that has spread and is no longer responsive to hormonal therapy. Ipilimumab is an immunotherapy that activates the immune system to detect and kill cancer cells.

Previous trials have shown that ipilimumab was effective at increasing the duration of survival without the progression of their disease. However, the overall survival benefit of ipilimumab in patients with mCRPC spread to the bone treated with radiotherapy is still under investigation.

There were 799 patients with mCRPC. All patients had previously been treated with docetaxel (Taxotere) chemotherapy. All patients had bone metastasis (cancer spread to the bones) and received radiotherapy (RT) for these metastasis. After 2 days from RT, patients received either ipilimumab (399 patients) or a placebo (400 patients). The average follow-up period was 50 months.

Overall survival (OS) after 2 years was higher in the ipilimumab group (25%) compared to the placebo group (17%). The 3-year OS rate was also higher with ipilimumab (15%) versus 7.9% in the placebo group. The 5-year OS rate was also higher with ipilimumab compared to placebo (7.9% vs. 2.7%) in the PA. 

Side effects in the ipilimumab group were similar to other trials involving this drug. The most common side effects related to ipilimumab treatment were skin and bowel-related such as itching, rash, diarrhea.

This study concluded that the addition of ipilimumab to radiotherapy for bone metastasis in men with mCRPC previously treated with docetaxel improved survival in the long-term. 

This study was sponsored by Bristol Meyers Squibb, the manufacturer of ipilimumab .