Seattle—A novel, investigational drug appears to be promising in rapidly suppressing HIV, according to study results announced at the 2017 Conference on Retroviruses and Opportunistic Infections.
Data from the Phase II study evaluating the efficacy, safety and tolerability of a combination of bictegravir (BIC) and emtricitabine-tenofovir alafenamide (FTC/TAF; Descovy, Gilead) versus dolutegravir (DTG; Tivicay, ViiV) and FTC/TAF in HIV patients who were treatment naive found that both of the combination regimens demonstrated high virologic response rates at weeks 24 and 48, according to Paul Sax, MD, the clinical director of infectious diseases at Brigham and Women’s Hospital, and a professor of medicine at Harvard Medical School, in Boston.
“Bictegravir plus FTC/TAF demonstrated very high rates of viral suppression through week 48—97% in the bictegravir arm, 91% in the dolutegravir arm—outstanding results for both study arms,” said Dr. Sax, who was the lead investigator of the study.
He added: “The time to virologic suppression [for BIC] was extremely fast. Most patients were virologically suppressed by week 4.”
In the blinded, placebo-controlled study, 98 treatment-naive, HIV-infected adults were randomly assigned 2:1 to receive either once-daily BIC+FTC/TAF (n=65) or DTG+FTC/TAF (n=33) for 48 weeks. At week 24, 97% (n=63/65) of patients taking BIC+FTC/TAF and 94% (n=31/33; 95% CI, P=0.50) 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, P=0.17) 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/mcL in the BIC+FTC/TAF arm and 192 cells/mcL in the DTG+FTC/TAF arm.
One patient in the BIC+FTC/TAF arm discontinued due to an adverse event of urticaria after the week 24 visit, he said. Median changes in estimated glomerular filtration by the Cockcroft-Gault formula at week 48 were –7.0 mL per minute for BIC+FTC/TAF and –11.3 mL per minute for DTG+FTC/TAF, with no discontinuations due to renal adverse events. 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.
“Both of the regimens were very well tolerated,” he said, adding that the study was simultaneously published in Lancet HIV (2017 Feb 14. [Epub ahead of print]).
Bictegravir is a novel, investigational, once-daily integrase strand transfer inhibitor being developed by Gilead Sciences. It is potent in vitro against wild-type and most integrase-resistant variants. It has a low likelihood of drug–drug interactions, has a long half-life and does not require boosting, he explained.
Bictegravir is currently in Phase III trials as part of a single-tablet regimen in combination with FTC/TAF for the treatment of HIV, according to Dr. Sax.
“The high virologic response rates seen in this study show that the pairing of bictegravir with FTC/TAF could potentially offer patients and physicians a new HIV treatment option with preclinical data supporting few drug interactions and a high barrier to resistance,” Dr. Sax said.