Gilead’s Bictegravir Shows Equivalent Efficacy to Tivicay in Phase 3 Trials

Data from three phase 3 ongoing HIV trials suggests fixed-dose combination treatment regimens containing the novel investigational integrase strand transfer inhibitor bictegravir are noninferior to those containing GlaxoSmithKline’s Tivicay. 

In addition, early data from a fourth trial also indicates similar results when switching to a bictegravir-containing regimen from a suppressive regimen of nucleoside/nucleotide reverse transcriptase inhibitors and a boosted protease inhibitor.

“This investigational single tablet regimen brings together the potency of an integrase inhibitor, bictegravir [BIC], with the demonstrated efficacy and safety profile of the [Truvada (emtricitabine/tenofovir alafenamide, Gilead) (FTC/TAF)] backbone,” Norbert Bischofberger, PhD, executive vice president and chief scientific officer at Gilead Sciences, said in a press release. “Based on the results from these Phase 3 studies, the combination of bictegravir and FTC/TAF could represent an important advance in triple-therapy treatment for a broad range of HIV patients, and we look forward to submitting regulatory applications in the U.S. and EU this year.”

In the first two studies, treatment naive patients (n = 600) randomly received the study treatment BIC/FTC/TAF, or a standard fixed-dose therapy of Triumeq (abacavir/dolutegravir/lamivudine, ViiV Healthcare) (ABC/DTG/3TC) or DTG+FTC/TAF. The primary endpoint in both of these studies was the proportion of patients with viral loads less than 50 copies/mL at week 48.

In another trial, virologically suppressed patients (n = 520) currently on a regimen of ABC/DTG/3TC or DTG+ABC/3TC were assigned to stay on the current regimen or switch to BIC/FTC/TAF. The fourth trial was an open-label study in which virologically suppressed patients (n = 520) on a boosted protease inhibitor with a backbone of ABC/3TC or FTC/TAF were randomly assigned to stay on their regimen or switch to BIC/FTC/TAF. The endpoint of these studies was the proportion of patients with viral loads equal to or exceeding 50 copies/mL at week 48.

The BIC/FTC/TAF treatment regimen met non-inferiority measurements in all four studies, and was well tolerated with no patients discontinuing medication due to renal events. No patients randomized to the BIC- or DTG-containing arms developed treatment-emergent resistance, while one patient randomized to the protease inhibitor arm in the fourth study developed an abacavir resistance mutation.

Gilead said it will be submitting in-depth data from each study for presentation at scientific conferences during 2017.—Dave Muoio