FDA Advisers Deal Setbacks to Two Cancer Drugs

An FDA advisory committee last week recommended against final approval for two oncology drugs that had been granted New Drug Application and priority review status by the agency despite mixed clinical results.

The FDA's Oncologic Drugs Advisory Committee (ODAC) ruled that Genasense (oblimersen sodium), a skin cancer drug developed by Genta in partnership with Aventis, did not prove effective enough in clinical trials in combination with chemotherapy to outweigh the risk of increased toxicity in patients who have not received prior chemotherapy.

The committee also ruled that a test group used by Allos Therapeutics for RSR13 (efaproxiral), a drug to treat brain metastases originating from breast cancer as an adjunct to whole-brain radiation therapy, was too small and that successful results should be considered "exploratory."

While Genasense did not hit a key target for extending life in a 771-person clinical trial, Genta presented data on the treatment's success at shrinking tumors and slowing the progress of the disease. Allos' 538-person, non-cancer-specific Phase III trial revealed a positive survival rate only among 115 breast cancer patients with brain metastasis.

Although the FDA committee's decision is not binding—the agency has at times ruled against ODAC findings—both companies concede a setback that will reverberate to contract fine chemicals manufacturers Hovione, which makes RSR13 for Allos, and Avecia, which manufactures the 18-nucleotide active ingredient in Genasense.