Last checked at 
LONDON, Feb 14 (Reuters) - Gilead Sciences hasthrown down a challenge to GlaxoSmithKline with goodclinical trial results for an experimental HIV drug that worksin the same way as the British group's successful dolutegravir.
Gilead's bictegravir, another so-called integrase inhibitordrug, delivered 97 percent virus suppression, making it just aseffective as GSK's product, data presented at a medical meetingin Seattle late on Monday showed.
Importantly, there were no cases of resistance emerging tothe new medicine in the 98-patient Phase II study and nopatients discontinued treatment due to kidney problems, whichcan be an issue with HIV treatments.
Potential drug resistance is a key consideration for the newdrug because dolutegravir is valued by doctors for its excellentresistance profile.
Berenberg analyst Laura Sutcliffe said the results were goodnews for Gilead but the data was not yet conclusive, sincefindings from larger Phase III tests are due later in the year.
Gilead is pinning its hopes on bictegravir to staycompetitive with GSK and the U.S. company has been testing thenew medicine alongside two older drugs.
GSK, meanwhile, is working on a dolutegravir-based two-drugtreatment regimen for controlling the virus behind AIDS, adevelopment that marks a departure from conventional triple drugcocktails.
Detailed findings from two Phase III trials testing the newtwo-drug combination were presented at the Conference onRetroviruses and Opportunistic Infections in Seattle. GSKalready said in December that these studies were successful.
GSK sells its HIV drugs through its majority-owned ViiVHealthcare unit, in which Pfizer and Japan's Shionogi hold minority stakes.
GSK shares were 0.6 percent lower by 0830 GMT. (Reporting by Ben Hirschler; Editing by Keith Weir)
