Boosting Immune System Slows Progression in Advanced Colorectal Cancer

Following up the combination regimen of gemcitabine (Gemzar) and FOLFOX with drugs designed to boost the immune system significantly improved progression-free survival (PFS) in patients with advanced colorectal cancer. Pierpaolo Correale MD, PhD, Siena University School of Medicine, Italy, noted that the benefits observed in the experimental arm of the trial led a monitoring committee to halt the trial early. Preliminary data were reported at the 102nd annual meeting of the American Association for Cancer Research being held in Orlando, Florida.

The phase 3 trial began enrolling patients in 2005, which Correale pointed out was prior to the routine use of monoclonal antibodies. The 130 patients recruited for the study were randomized to chemotherapy with a doublet of gemcitabine and FOLFOX followed by granulocyte-macrophage colony stimulating factor and low-dose aldesleukine (GOLFIG) or FOLFOX alone.

Patients continued treatment for up to 12 cycles and were then given maintenance therapy until progression. Median PFS for patients in the GOLFIG arm was 16.5 months compared with 7.5 months for patients in the FOLFOX-only arm. According to Correale, using FOLFIRI or FOLFOX regimens alone to treat advanced colorectal cancer typically results in overall survival (OS) of 8 to 10 months; adding a monoclonal antibody to a standard chemotherapy regimen can improve OS to 20 to 22 months. OS for each group in the study was not reported. Correale said, "Based on our experience and results to date, we believe that the GOLFIG regimen is superior to FOLFOX chemotherapy in terms of efficacy and comparable in terms of toxicity and cost." He said the next step would be to compare the GOLFIG protocol to regimens containing standard chemotherapy and a monoclonal antibody.

A discussant at the presentation, Igor Astsaturov, MD, assistant professor of medical oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, noted that some patients with metastatic colorectal cancer are not candidates for some of the commonly used monoclonal antibodies due to KRAS or other mutations. Confirmation of the results with GOLFIG could lead to a new standard of care for these patients.