UPDATE: 2007 NASSO conference hears encouraging data on GSK's alli, Orexigen's Contrave et al

In the face of growing concerns about an obesity epidemic, weight-loss drugs, with their high margins, are an attractive target for drugmakers. Data from IMS Health show that, in the year to June 2007, UK sales of prescription obesity drugs reached $121.0 million, with volumes almost double those of five years ago. However, this drug category was rocked earlier this year by the US Food and Drug Administration's rejection of Sanofi-Aventis' Acomplia (rimonabant) because of links to depression (Marketletters passim). The agent is approved and on sale in several European markets but is unlikely to achieve its predicted blockbuster status without clearance in the lucrative US market.

Although Acomplia's rejection poses a setback to the entire category, a wealth of new data on the latest obesity drug candidates was presented at the 2007 annual scientific meeting of the North American Association for the Study of Obesity, recently held in New Orleans. Delegates heard encouraging patient satisfaction data on alli (orlistat 60mg), the only US Food and Drug Administration-approved, over-the-counter weight-loss product. According to UK-based GlaxoSmithKline, which licensed the OTC form of the agent from Switzerland's Roche, the data show that the weight loss achieved with alli strongly motivates subjects to continue treatment regardless of whether they are experiencing side effects. Two million alli starter packs have been sold since the product was launched five months ago, and GSK expects annual sales to hit $1.5 billion.

This cumulative data analysis evaluated controlled and non-controlled studies on orlistat 60mg to examine the overall tolerability profile. According to GSK, the analysis shows that, during the first week of treatment, the overall incidence of most treatment effects was generally low (3% to 8%). In addition, the overall rate was 33% lower than those on 120mg orlistat, which is the prescription strength dose, sold by Roche as Xenical, the current market leader. In fact, researchers found that when alli was used for three months without physician supervision in a non-controlled setting, the overall incidence of treatment effects was 20% lower compared to controlled studies. These data support the proposition that most patients can successfully modify their eating habits to comply with the alli plan, GSK noted.