CROI 2017: High Virologic Response Seen with Bictegravir

Gilead faces competition from dolutegravir, which is already approved by the Food and Drug Administration.

A combination of Gilead Science's bictegravir (75 mg) and emtricitabine/tenofovir alafenamide (200/25 mg) [BIC+FTC/TAF] held up well in a phase 2 clinical trial that compared the treatment to dolutegravir (Tivicay, ViiV Healthcare, a specialist HIV company majority-owned GlaxoSmithKline) and FTC/TAF, according to a presentation at the Conference on Retroviruses and Opportunistic Infections 2017 being held in Seattle this week.

Paul Sax, MD, of Brigham and Women’s Hospital, Professor of Medicine at Harvard Medical School and the lead study investigator, discussed the findings at a media briefing on the meeting, calling the results "outstanding." He noted that both regimens demonstrated high virologic response rates at weeks 24 and 48; 97% (63 out of 65 patients) at week 24 for patients of patients taking BIC+FTC/TAF and 94% (n=31/33; 95% CI: -8.5% to 14.2%, P=.50) of patients taking DTG+FTC/TAF achieved HIV-1 RNA levels less than 50 copies/mL.

At week 48, 97% (n=63/65) of patients taking BIC+FTC/TAF and 91% (n=30/33; 95% CI: -6.0% to 18.8%, P=.17) of patients taking DTG+FTC/TAF achieved HIV-1 RNA levels less than 50 copies/mL.

No viral resistance was detected in the BIC+FTC/TAF arm. Mean CD4 count increases at week 48 were 258 cells/µL in the BIC+FTC/TAF arm and 192 cells/µL in the DTG+FTC/TAF arm.

Dr Sax noted that one patient in the BIC+FTC/TAF arm discontinued due to an adverse event of urticaria following the week 24 visit. There were no treatment-related serious adverse events and no deaths in either arm, and the most commonly reported adverse events were diarrhea and nausea.

Four phase 3 trials for bictegravir are currently underway and results on those trials are expected by the end of this year, Dr. Sax noted.

Reference

Sax P. Randomized trial of bictegravir or dolutegravir with FTC/TAF for initial HIV Therapy. Paper presented at: 2017 Conference on Retroviruses and Opportunistic Infections (CROI); Feb. 14, 2017; Seattle.