Combining the immune stimulator GM-CSF with the antibody drug ipilimumab created a synergistic effect that prolonged survival in patients with metastatic melanoma and reduced the incidence of the most serious side effects, according to a trial led by researchers at Dana-Farber Cancer Institute.
Interim results of the phase II randomized trial showed that patients receiving the combination of ipilimumab and GM-CSF had a median survival of 17.5 months to date, compared to12.7 months for patients treated only with ipilimumab, said F. Stephen Hodi, MD, the study’s first author and the director of the melanoma center at Dana-Farber. The final median survival for the combination therapy has not yet been reached.
"The combination was better tolerated, in terms of fewer high-grade adverse events, particularly those affecting the gastrointestinal system and the lungs,” Hodi said. Treatment with ipilimumab has been associated with serious side effects, including perforation of the colon and respiratory failure. Ipilimumab is a monoclonal antibody that binds to a protein, CTLA-4, which in effect “takes the brakes off” the immune system’s attack on cancer cells, Hodi said
Adding GM-CSF to ipilimumab appears to lower the incidence of these potentially life-threatening adverse consequences, Hodi said.
GM-CSF is a white blood cell growth factor use for support in patient undergoing high-dose chemotherapy; it also helps present invading proteins to the immune system for attack in fighting infections.
The study enrolled 245 patients with metastatic melanoma who had no more than one previous therapy. Patients were assigned to receive either ipilimumab alone or ipilimumab followed by ipilimumab with GM-CSF.
Hodi said that the study used doses of ipilimumab higher than those approved by the Food and Drug Administration. Depending on how individual clinicians interpret the study, he added, “these results could be practice-changing; there really is no downside to adding GM-CSF.”
The study was part of a NCI-CTEP Easter Cooperative Oncology Group (ECOG) trial.
In addition to Hodi, the study’s other authors are Sandra J. Lee, ScD, Dana-Farber; David F. McDermott, MD, Beth Israel Deaconess Medical Center, Boston; Uma N. M. Rao, MD, Lisa H. Butterfield, PhD, Ahmad A. Tarhini, MD, and John M. Kirkwood, MD, University of Pittsburgh Cancer Institute; Philip D. Leming, MD, Cincinnati Hematology Oncology, Cincinnati, OH; and Igor Puzanov, MD, Vanderbilt University Medical Center, Nashville, Tenn.