In August, the first Phase III study of Quad showed that it was as effective as Gilead's big-selling combo Atripla (efavirenz/tenofovir/emtricitabine). Dr Bischofberger said that based on the availability of data from both studies, "we are now working toward filing for US regulatory approval of Quad by the end of the year". Previously, Gilead had been looking at filings in the first quarter of 2012.