The FDA approved Bristol-Myers Squibb’s cancer biologic Yervoy (ipilimumab) for the treatment of late-stage melanoma, a particularly deadly form of skin cancer for which treatment options are few. One analyst projected that sales of the drug could top $1.7 billion by 2015.

Yervoy is a monoclonal antibody, delivered intraveneously, that is thought to fight melanoma by thwarting a molecule that baffles the body’s immune system, allowing it to detect and kill the cancer cells. In an international study of 676 patients who had stopped responding to other treatments, those patients given Yervoy or Yervoy plus an experimental vaccine lived an average of around ten months, while those receiving the vaccine, called gp100, lived an average of 6.5 months.

“Late-stage melanoma is devastating, with very few treatment options for patients, none of which previously prolonged a patient’s life,” said Dr. Richard Padzur, MD, director of the Office of Oncology Drug Products in FDA’s Center for Drug Evaluation and Research. “Yervoy is the first therapy approved by the FDA to clearly demonstrate that patients with metastatic melanoma live longer by taking this treatment.”

The therapy is being approved with a Risk Evaluation and Mitigation Strategy owing to “severe to fatal autoimmune reactions” seen in 13% of patients treated with Yervoy.

Bernstein analyst Tim Anderson forecast $1.7 billion in sales of the biologic by 2015, while a consensus forecast of four analysts by Thomson Reuters put sales at $820 million by then.

According to the National Cancer Institute, 68,130 new cases of melanoma were diagnosed in the US last year, with about 8,700 people dying from the disease.