Panel Backs Glaxo Rare-Cancer Therapy; Rejects Merck Drug

GlaxoSmithKline Plc’s drug for a rare, often deadly form of cancer won the backing of U.S. advisers, while a similar treatment from Merck & Co. and Ariad Pharmaceuticals Inc. failed to gain support.

A Food and Drug Administration advisory panel today determined the benefits of the Glaxo treatment outweighed the risks while the therapy from Merck and Ariad didn’t. The agency isn’t required to follow the panel’s recommendations.

If approved, Votrient from London-based Glaxo and ridaforolimus, developed by Merck and Ariad, would be the first targeted treatments for a cancer that invades soft tissue such as muscle, tendons and fat outside the stomach and intestines. Chemotherapy is now used for these tumors, which are diagnosed in about 10,000 patients a year.

“Everyone wants better therapies to be available,” Wyndham Wilson, the panel chairman and chief of the National Cancer Institute’s Lymphoma Therapeutics Section, said during the meeting. “The story is told in what the actual delay in progression-free survival is.”

Glaxo’s Votrient kept sarcoma from spreading in soft tissue three months longer than placebo. Ridaforolimus stopped progression of the cancer three weeks longer than placebo. Patients in clinical trials experienced heart, kidney and liver disorders.

Panel Votes

The panel vote 11-2 that Votrient’s benefits outweighed its risks and 13-1 that the risks of ridaforolimus outweighed the drug’s potential benefits. The advisers met in Silver Spring, Maryland.

Ariad fell 2 percent to $14.75 at 4:50 p.m. New York time in extended trading. Merck fell less than 1 percent to $37.73. Glaxo gained less than 1 percent to close at 1,433.5 pence in London trading.

The agency is set to decide on Glaxo’s drug by May 6 and the medicine from Merck and Ariad by June 5.

“Merck remains confident in the potential of the investigational agent ridaforolimus for an indication where patients have limited options,” said Eric Rubin, vice president, clinical research oncology, at the Whitehouse Station, New Jersey-based drugmaker. “We remain committed to bringing forward this promising therapy for patients with metastatic sarcoma, and will continue to work with the FDA to address the committee’s questions.”

Tumor Types

There are about 50 types of soft-tissue sarcoma, which are different from carcinomas that arise from cells, according to the American Cancer Society. Most sarcomas are in the arms and legs or internal organs, according to the National Cancer Institute.

The median survival of patients diagnosed with soft-tissue sarcoma that is spreading is about a year, according to the FDA documents.

Sarcoma tumors also can develop in bone tissue. About 2,500 new cases are diagnosed a year, according to the University of California, San Francisco. Ridaforolimus, the experimental drug from Merck and Cambridge, Massachusetts-based Ariad, also would treat bone sarcoma.

Chemotherapy is effective at shrinking the tumor in 20 percent to 25 percent of patients, said Scott Okuno, an oncologist at the Mayo Clinic in Rochester, Minnesota. Once tumors have spread, a minority of patients are cured, he said in a telephone interview.

Study Results

Glaxo’s Votrient, chemically known as pazopanib, enabled patients to live a median of 4.6 months, or 3.1 months longer than a placebo, while the disease stopped advancing, according to a company statement. The final-phase trial studied 369 patients, including 246 on the drug, with certain metastatic soft tissue sarcomas that have tried chemotherapy.

The trial excluded patients with gastrointestinal tumors. The FDA approved Votrient in 2009 to treat advanced renal cell carcinoma.

“It’s a little step but it’s a little step in a field that has had nothing,” Lee Helman, a panel member and scientific director for clinical research at the National Cancer Institute’s center for cancer research, during the meeting.

Ridaforolimus didn’t have the same benefit, the panel said.

Patients stayed alive and free of disease progression on ridaforolimus, which may be called Taltorvic if approved, for a median of 17.7 weeks, or 3.1 weeks longer than placebo, according to an FDA staff report. The final-phase trial tested 711 patients, 347 on the compound, with soft-tissue sarcoma that spread to other areas of the body or bone sarcomas whose disease hadn’t progressed after at least four cycles of chemotherapy.

Since patients can’t stay on chemotherapy indefinitely because of harsh side effects, ridaforolimus would be used to delay progression of the disease after the treatment.

Merck is responsible for the development and worldwide commercialization of ridaforolimus in oncology, while Ariad has co-promotion rights in the U.S., Pamela Eisele, a Merck spokeswoman, said in an e-mail.

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