MS Drug Gets Stronger Alert; Trial of Another SuspendedMar 17, 2005 | USA TODAY Avonex, the No. 1-selling drug for treating multiple sclerosis, might cause liver failure in rare cases and will carry a stronger warning label, the Food and Drug Administration and maker Biogen Idec (BIIB) said Wednesday.
The stronger warning will match one already on rival drug Rebif and underscores dangers that have long been known with that class of drugs, doctors say.
Still, the news was another blow to the MS community. Last month, Biogen and partner Elan (ELN) pulled the promising MS drug Tysabri from the market after one patient taking it died from a rare brain infection and another contracted the same condition.
More bad news came Wednesday when the FDA and drugmaker GlaxoSmithKline (GSK) suspended a clinical trial of a new drug in the same class as Tysabri. The drug hadn't been approved for sale to consumers. The trial, involving 400 patients, was suspended until more is known about what happened with Tysabri. "I imagine the FDA is trying to be as cautious as possible," says Nicholas LaRocca, an MS specialist at the National Multiple Sclerosis Society. Glaxo said it hopes to restart the trial. There are about 150 MS drug trials underway, many of which don't include Tysabri-like drugs.
MS is a progressive disease of the central nervous system that affects more than 400,000 people in the USA and more than 1 million worldwide. Avonex, Tysabri and other drugs are intended to slow the disease's progression.
LaRocca says the withdrawal of Tysabri and the suspension of the Glaxo trial represent a "chink in optimism for the future" of MS treatments, but five other drugs, including Avonex, are still available.
Biogen, which has said it hopes to return Tysabri to market, wouldn't say how many Avonex users had liver failure. But it said the condition was "very, very rare" and that it sees the label change as "minor."
Biogen's competitors may not benefit much because some pose the same liver risk, but the overall risk is small, says Winton Gibbons, biotech analyst for William Blair.