Among patients with previously treated, advanced melanoma, treatment with the investigational drug ipilimumab improved overall and progression-free survival. The results of this Phase III clinical trial were presented at the 2010 annual meeting of the American Society of Clinical Oncology.
Melanoma is the most deadly type of skin cancer. Each year in the United States, there are roughly 68,000 new diagnoses of melanoma and 8,700 deaths from the disease. Finding effective treatments for advanced melanoma has been challenging, and research in this area continues.
Ipilimumab is an investigational drug that targets a molecule known as CTLA4. CTLA4 is found on the surface of T cells and is thought to inhibit immune responses. By targeting this molecule, ipilimumab may enhance the immune system’s response against tumor cells.
To evaluate ipilimumab in the treatment of melanoma, researchers conducted an international Phase III clinical trial among 676 patients with previously treated, Stage III or Stage IV melanoma.
Patients were assigned to one of three treatment groups: 1) ipilimumab; 2) ipilimumab plus the gp100 vaccine; or 3) the gp100 vaccine alone. The gp100 vaccine is an experimental melanoma vaccine that is also designed to stimulate T cells to attack melanoma cells. In previous studies it has shown modest anticancer activity and was superior to treatment with IL-2.
- Median overall survival was 10 months in the groups that received ipilimumab, compared with 6.5 months in the group that received the gp100 vaccine alone.
- Two-year survival was 24% among patients who received ipilimumab alone, 22% among those who received ipilimumab and the gp100 vaccine, and 14% among those who received the gp100 vaccine alone.
- Six-month progression-free survival was 30% among patients in the ipilimumab groups and 11% among patients in the group that received the gp100 vaccine alone.
- Ipilimumab was generally well tolerated, but 10-14% of patients treated with ipilimumab experienced sometimes severe side effects such as rash and colitis (inflammation of the colon). The frequency among patients treated with gp100 was roughly 3%.
These results suggest that ipilimumab may delay cancer progression and improve overall survival among patients with previously treated, advanced melanoma. The addition of the gp100 vaccine to ipilimumab did not appear to further improve outcomes.
Reference: O’Day S, Hodi FS, McDermott DF et al. A phase III, randomized, double-blind, multicenter study comparing monotherapy with ipilimumab or gp100 peptide vaccine and the combination in patients with previously treated, unresectable stage III or IV melanoma. Presented at the 2010 annual meeting of the American Society of Clinical Oncology. June 4-8, 2010. Chicago, IL. Abstract 4.