The FDA on Friday granted Biogen Inc. almost, but not quite, everything the company had been hoping for in the agency's marketing approval of Avonex beta interferon for multiple sclerosis.

The approval covers all relapsing forms of MS. Avonex is indicated to slow the accumulation of physical disability and to decrease the frequency of clinical exacerbations in relapsing MS. That label makes it the only drug approved to slow the progression of disease. Betaseron, the form of beta interferon marketed by Berlex Laboratories Inc. and manufactured by Chiron Corp., is indicated for reduction of exacerbations in relapsing/remitting MS.

The only downside for BGEN is that the FDA asked the company to blend the data on exacerbations for the package insert. Combining all patients in the study, no matter how long or short a time they had been on Avonex, results in exacerbation rates in the treatment group of 0.67 per year versus 0.82 in the placebo group, a reduction of 18 percent.

Promotional leeway

In its scientific presentations, the company and clinical investigators focused on patients who had been on drug for two years, because that group was more directly comparable to data from Betaseron. For patients who were on Avonex for two years, there was a 32 percent reduction in exacerbations, from 0.9 to 0.6 per year.

While those numbers aren't in the package insert, that may not matter much. The FDA is allowing BGEN to use the two-year data in its promotional material. "We were a little bit disappointed, but with our selling and promotional material, we will overcome this quickly," said Ken Bate, vice president of sales and marketing.

BGEN, which has its manufacturing, distribution and sales force in place, was to begin marketing Avonex today. The company's sales force includes 50 reps, plus another 10 regional managers and account personnel. BGEN said it has sufficient drug available to treat all patients.

The company is pricing Avonex to be competitive with Betaseron, which costs patients $9,864 a year, according to Jeffrey Latts, vice president of R&D and chief medical officer at Berlex. Avonex will cost about $9,890, Bate said.