Human Genome Sciences Inc. and GlaxoSmithKline PLC said Friday that the Food and Drug Administration wants three more months before making a decision on their lupus drug candidate Benlysta, delaying the agency's decision until around March 10.
The news sent Human Genome shares down 6 percent to $24.06 in aftermarket trading, having earlier closed at $25.60.
The companies said the FDA wanted more information about Benlysta following an advisory committee meeting in November. They say they have submitted that data. The FDA was scheduled to make a decision on Benlysta by Dec. 9. If approved, it would be the first new lupus therapy to reach the market in more than 50 years.
Human Genome Sciences had said it could get Benlysta to the market in the first quarter of 2011 if it was approved this month. Analysts expect Benlysta sales to eventually reach more than $1 billion a year.
In November, an FDA panel recommended approving Benlysta as a treatment for the symptoms of lupus, an autoimmune disease in which the body attacks its own tissues and organs. However, the panel had questions about Benlysta's effectiveness because studies showed the drug does not work on all patients. For example, it did not help African-Americans during clinical testing, and African-Americans are three times more likely to develop lupus than Caucasians. Those issues could lead to greater restrictions on Benlysta's use.
Human Genome Sciences of Rockville, Md., and GlaxoSmithKline of London began collaborating on Benlysta in 2006.
Shares of GlaxoSmithKline shares gained 25 cents to close at $39.19 Friday and lost 4 cents to $39.15 in aftermarket trading.