Merck's Isentress aces HIV combo study

Good news for Merck's (NYSE: MRK) HIV drug franchise. The company's Isentress drug fought off the virus as well as older drugs did, when used as start-up therapy in combination with Abbott Laboratories' (NYSE: ABT) Kaletra treatment. It's the sort of research that could affect doctors' prescribing habits, because physicians are looking for HIV treatments that are safer when used for years, experts tell Bloomberg.

"Patients are now living longer and while viral suppression is still a concern, for many patients the major concern is the long-term effects and premature aging related to the drugs," explains lead researcher Esteban Martinez of the University of Barcelona.

And Isentress might be free of some of its rival drugs' known side effects. According to a new study, patients who switched to Isentress from Kaletra kept HIV at bay just as well, and after 48 weeks of therapy, had lower cholesterol than patients still using Kaletra. This research contradicts an earlier company-funded study that found patients who switched were more likely to have a relapse.

Abbott is considering developing a new combination pill--either Kaletra plus Isentress or Kaletra plus Truvada--and that's why it funded the combination-therapy study. Isentress coupled with Kaletra pushed HIV to undetectable levels in 83 percent of patients, compared with 85 percent of those using Truvada with Kaletra. Abbott says it's waiting for longer-term data before deciding which combo to bet on--with a particular eye to side effects.

- see the Abbott release
- read the Bloomberg story