The present clinical trial evaluated the safety of an immune-based therapy (termed ‘combined immunotherapy’) as an alternative to chemotherapy for the treatment of metastatic (spread with distant metastases) prostate cancer non-responsive to hormonal treatment, or ‘castration-resistant prostate cancer’ (mCRPC).
The trial aimed at establishing the highest tolerated dose for patients treated with GVAX, a whole cell vaccine with anti-tumor properties, in combination with Ipilimumab (Yervoy), an antibody that stimulates the body’s immune system. The study concluded that GVAX in combination with Ipilimumab is safely tolerated and induced a clinically relevant immune response, leading to an improved survival rate.
In total, 28 mCRPC patients were enrolled and treated with a fixed dose of the GVAX vaccine, plus varying (escalated) doses (0.3-5mg/kg) of Ipilimumab for a period of 24 weeks. Patients were monitored for immune-related adverse responses to either one of the drugs as well as for drug effectiveness. Vaccine-related adverse events (reported at higher doses of Ipilimumab) were manageable and included injection-site reactions, fatigue and fever. Clinically relevant changes like Prostate-specific antigen (PSA) level, bone scan results and overall survival rate were recorded during and after treatment for up to 70 months. A significantly improved overall survival rate (46.5 versus 20.6 months) was observed in 12 patients who became immunized to prostate-specific membrane antigen (PSMA). This positive, tumor-specific immune response was limited to patients who had received higher doses of GVAX plus Ipilimumab (3 or 5mg/kg).
In this pilot study, an immunotherapy schedule of GVAX plus 3mg/kg Ipilimumab was found to be safe and associated with an increased survival rate, suggesting that it may provide an alternative treatment option to chemotherapy in patients with mCRPC.
Published By :
Lancet oncology
Date :
May 01, 2012
