Gilead's bictegravir meets endpoints but does not beat dolutegravir

US biotech major Gilead Sciences (Nasdaq: GILD) today announced that its four Phase III clinical studies evaluating the investigational fixed-dose combination of bictegravir, emtricitabine and tenofovir alafenamide (BIC/F/TAF) have met their primary end point for the treatment of HIV-1.

Three of the ongoing studies are designed to explore the efficacy and safety of BIC/F/TAF compared to regimens containing dolutegravir (50mg; DTG) among treatment-naïve patients (Studies 1489 and 1490), and among virologically suppressed patients switching from an existing antiretroviral regimen (Study 1844). A fourth ongoing study in virologically suppressed patients compares switching to BIC/F/TAF versus remaining on a suppressive regimen of two nucleoside/nucleotide reverse transcriptase inhibitors and a boosted protease inhibitor (Study 1878).

BIC/FTC/TAF met the definition of non-inferiority in all four studies, with comparable proportions of patients having HIV-1 RNA <50 copies/mL (Studies 1489 and 1490) and HIV-1 RNA ≥50 copies/mL (Studies 1844 and 1878). In all studies BIC/FTC/TAF was well tolerated and no patients discontinued study medication due to renal events. No patients randomized to the bictegravir or dolutegravir arms developed treatment-emergent resistance. One patient randomized to the protease inhibitor arm in Study 1878 developed an abacavir resistance mutation (L74V).