New Clinical Trials Offer Promise for Melanoma Treatments
Melanoma is the deadliest form of skin cancer. Although the World Health Organization estimates that melanoma accounts for only 5% of skin cancer cases — or 132,000 annual cases globally — it accounts for 75% of skin cancer deaths. However, compared with other cancer types, melanoma remains a small area of study. ClinicalTrials.gov shows that, over the past 10 years, excluding studies of unknown status, there have been approximately 1,070 melanoma clinical trials testing. According to Biopharm Insight, 15 approved melanoma treatments exist, with another 49 active drug programs in Phase 3.
One Phase 3 study is Amgen’s clinical trial, which targets the treatment of late-stage melanoma. Begun in April 2009, the trial will run through September 2014 with a planned total enrollment of 439 patients across sites in the US, the UK, Canada and South America. The trial compares the efficacy of a biologic already used to treat melanoma (“subcutaneous granulocyte-macrophage colony-stimulating factor,” or GM-CSF for short) against a new biologic — a genetically modified version of the type one herpes simplex virus.
The trial uses talimogene laherparepvec (brand name: OncovexGM-CSF) to treat patients with IIIB, IIIC or IV melanoma who have not undergone surgery to remove all or part of their cancerous tissues. The experimental treatment replicates itself within tumor tissues until it effectively destroys the cancerous cells. Then, the virus spreads to the tumor tissues, releasing GM-CSF, which its creators engineered the virus to express. Upon its release, GM-CSF — a white blood cell growth factor — chemically triggers patients’ immune systems to kill tumor cells. Of this treatment, Sean E. Harper, MD and executive vice president of R&D at Amgen said, “We believe the innovative mechanism of action of talimogene laherparepvec may offer a promising approach for these patients.”
Recently, Amgen announced top-line results from its study. These findings support the trial’s primary endpoint: demonstrating a durable response rate (DDR) that lasts continuously across six months. Of the control group patients who received only the GM-CSF injection, 2% reported a substantial decrease in tumor size or elimination of the tumor altogether across a six month period. Roughly, 16% of patients in the experimental group reported the same result. The trial has yet to demonstrate its secondary endpoint of significant overall survival rates but expects these rates to become statistically significant as the trial moves forward in 2013.