SEATTLE — Results from a phase 2 randomized clinical trial show that Gilead Sciences’ investigational HIV drug bictegravir was both effective and well tolerated in adults compared with the integrase inhibitor Tivicay.
The study compared bictegravir with Tivicay (dolutegravir, ViiV Healthcare) in combination with Descovy (tenofovir alafenamide and emtricitabine, Gilead Sciences; TAF/FTC) in treatment-naive patients with HIV. Paul E. Sax, MD, clinical director of the HIV program at Brigham and Women’s Hospital, presented the findings.
“Integrase inhibitors are increasingly important as part of initial therapy, and our existing integrase inhibitors include [Isentress (raltegravir, Merck)], elvitegravir, which is boosted with cobicistat, and dolutegravir,” he said during a press conference. “Bictegravir is an investigational integrase inhibitor that’s very potent … allows once-daily dosing without boosting, and also has activity against both wild-type and most integrase-resistant viruses.”
In the study, 95 patients were randomly assigned 2:1 to receive blinded treatment with either 75 mg bictegravir or 50 mg dolutegravir once daily. Both treatment arms were given an additional 25 mg TAF and 200 mg FTC. The primary endpoint was the proportion of patients with HIV RNA less than 50 copies/mL at week 24. The study was not adequately powered to evaluate noninferiority, Sax said.
According to Sax, the results were “outstanding” in both treatment arms, with 97% of patients in the bictegravir arm and 94% of patients in the dolutegravir arm having HIV RNA less than 50 copies/mL at week 24. At week 48, 97% of those taking bictegravir and 91% taking dolutegravir achieved virologic success. Given the number of people enrolled in the study, these differences were not statistically significant, Sax said.
Sax mentioned three patients who met the study criteria for virologic failure and who had their virus sequenced for resistance. However, “no significant resistance was detected in any patients in either the bictegravir or dolutegravir arms,” he said. Both regimens were “extremely well tolerated,” he added. One patient in the bictegravir arm, who entered the study with a history of allergic dermatitis, experienced worsening symptoms and was forced to stop treatment before week 48 — the only study drug discontinuation, Sax said.
Sax said the data were promising enough to move into phase 3 testing, where the combination of bictegravir/TAF/FTC is being evaluated in single-tablet form.
On the same day, GlaxoSmithKline released new data from the SWORD I and II trials, which sought to simplify treatment by switching virologically suppressed patients from a three- or four-drug regimen to a two-drug regimen with dolutegravir and Edurant (rilpivirine, Janssen). Results from those studies, initially reported in December 2016, showed that the dolutegravir/rilpivirine combination was noninferior to standard treatment using more drugs. – by John Schoen
Sax PE, et al. Abstract 41. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 13-16, 2017; Seattle.
Llibre JM, et al. Abstract 44LB. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 13-16, 2017; Seattle.
Janssen Sciences Ireland UC. Positive Results From First Phase III Studies of Investigational Two-Drug HIV Treatment Regimen. http://www.prnewswire.com/news-releases/positive-results-from-first-phase-iii-studies-of-investigational-two-drug-hiv-treatment-regimen-300381576.html. Accessed February 9, 2017.
Disclosure: Sax reports receiving research grants from AbbVie, Bristol-Myers Squibb, Gilead Sciences, GlaxoSmithKline, Merck and Janssen.