By Deena Beasley
CHICAGO (Reuters) - An experimental drug from Bristol-Myers Squibb shrank tumors in 31 percent of patients with advanced melanoma, the deadliest form of skin cancer, according to results from an early-stage trial.
The drug, nivolumab, is the most advanced in a new class of immunotherapies designed to work by disabling a brake on the immune system's ability to attack cancer cells.
An existing immunotherapy drug, Bristol's Yervoy, which works by disrupting a different cell receptor, has been shown to be effective in up to 10 percent of people with advanced melanoma.
Researchers said earlier this month that a small study found that treating melanoma patients with a combination of both nivolumab and Yervoy, or ipilimumab, caused tumors to shrink by at least half in 53 percent of patients.
"Nivolumab is a real breakthrough drug for patients with metastatic melanoma, and probably for other diseases, too," said lead study author Dr Mario Sznol, a professor of medical oncology at the Yale Cancer Center in New Haven, Connecticut.
Nivolumab is being studied in patients with a range of different cancers, including lung and kidney.
In the melanoma study, 107 patients were treated with five different doses of nivolumab. All patients had cancer that had worsened despite prior treatment with standard drugs.
The updated results were presented on Saturday at a meeting of the American Society of Clinical Oncology in Chicago.
Overall, 33 patients experienced tumor shrinkage of at least 30 percent and responses were seen at all doses, according to researchers.
The median overall survival across all doses was 16.8 months and was 20.3 months for patients treated with the dose that was chosen for use in subsequent clinical trials. Randomized Phase 3 trials are underway to confirm the findings.
(Reporting By Deena Beasley; Editing by Tim Dobbyn)