tiistai 25. elokuuta 2009
Safety review for obesity drug
The US Food and Drug Administration announced yesterday (August 24) that it was reviewing reports of liver injury -- including 6 cases of liver failure and 27 hospitalizations -- in patients taking the weight loss drug orlistat, marketed by GlaxoSmithKline (GSK) and Roche.
In 2007, GSK's formulation of orlistat, alli -- so named to sound connote an ally in weight loss -- became the first diet drug to be sold over-the-counter (OTC). GSK paid $100 million to purchase the licensing rights to orlistat from Switzerland-based manufacturer Roche, who developed and still markets the prescription version, Xenical. (The Scientist wrote about the deal and the lengthy process of turning orlistat into an OTC drug in a feature article last year.) In 2008, its first full year as an OTC diet drug, alli's sales were estimated at $500 million, with future projections of $1 billion annually, according to Wall Street analysts.
Rare cases of liver problems were observed in patients taking the Roche's drug Xenical before, but when GSK first launched alli greater concern lay with its most common side effects, such as diarrhea, oily stools, and gas, which could be effectively managed by a healthy diet. The FDA said yesterday that it is reviewing the 32 cases of serious liver injury in patients taking orlistat -- most often signaled by yellowing of the skin or the whites of the eyes (jaundice), weakness, and stomach pain -- reported between 1999 and 2008. Thirty of the reports came from outside the US before orlistat was marketed as the OTC alli, said FDA spokesperson Siobhan DeLancey. The two most recent cases, however, were both in the US and associated with alli, she said.
"Right now, this is designed just to alert consumers and medical professionals that there may be a connection between the use of this drug and liver injury," DeLancey said. "We haven't established a conclusive link at this point."
Both Roche and GSK downplayed concerns regarding orlistat's role in liver injury. Yesterday's report is an update on an ongoing study by the FDA as "part of their regular communications," said GSK spokeswoman Deborah Bolding. Furthermore, GSK said in a statement that "there is no obvious biological mechanism to explain how liver damage can occur with alli," which acts in the gastrointestinal tract to block one-quarter of the fat a person ingests. Roche said in a statement that no "definite association" has been made between liver injury and Xenical. "The efficacy and safety of Xenical are supported by more than 10 years of clinical experience and over 35 million patients have been treated worldwide."
Lähde: The Scientist