BOSTON — HIV-positive patients can be safely switched from one integrase inhibitor to the new agent bictegravir (Biktarvy) without loss of efficacy or additional adverse events, researchers reported here.
Of 282 patients treated with bictegravir, which is coformulated with emtricitabine and tenofovir alafenamide (Descovy), 264 achieved an undetectable viral load using the 50 copies/mL assay after 48 weeks compared with 267/281 patients who remained on a regimen of dolutegravir plus abacavir and lamivudine (P=0.59), according to Jean-Michel Molina, MD, of St. Louis Hospital in Paris, colleagues.
“Our study shows that we have an effective option for patients who may need to switch to another regimen,” Molina said at a press conference at the Conference on Retroviruses and Opportunistic Infections (CROI).
He said the results fell well within the prespecified criteria for noninferiority for efficacy in the trial. and that “No treatment-emergent resistance was observed in either arm.”
The phase III, randomized, double-blind, multicenter, active-control study was conducted in North America, Europe, and Australia. Patients were assigned to receive a fixed-dose combination of 50 mg bictegravir/200 mg emtricitabine and 25 mg tenofovir once daily, or a dose of dolutegravir/abacavir/lamivudine (50, 600, 300 mg, respectively) once daily. They were followed for 48 weeks.
Eligible patients had been diagnosed with HIV infection, and had been successfully suppressed on the dolutegravir regimen. Active hepatitis B infection was not permitted, and patients were only allowed in the study if they had no resistance to the study drugs.
The median age of the patients in the bictegravir arm was 47 versus a median age of 45 in the dolutegravir arm. About 88% of the bictegravir patients were men compared with 90% of those on dolutegravir. About 73% of the participants were white and 21% were black. The median CD4-positive cell count was 732 cells/μL compared with 661 cell/μL among the patients assigned to receive dolutegravir. The median estimated glomerular filtration rate (EGFR) was 101 uL/min in both groups at baseline.
About 79.8% of patients taking bictegravir reported any kind of adverse event compared with 80.1% of patients on the dolutegravir-based regimen. Upper respiratory tract infections occurred in 10% of each cohort, and was the most common adverse event reported by the patients. Also, 8% of the bictegravir patients and 16% of the dolutegravir patients experienced drug-related adverse events, more often gastrointestinal events and abnormal dreams in the dolutegravir-treated patients.
Laboratory abnormalities were observed in 17% of the bictegravir patients and in 11% of the dolutegravir patients, with elevations in liver function tests occurring more frequently among the patients on the bictegravir regimen.
The researchers observed a slight decline in EGFR among the patients on the dolutegravir regimen while no change was observed among the patients on bictegravir. Albumin creatinine was not statistically different (P=0.74), while retinol-binding protein creatinine was not statistically different (P=0.31), and Beta2-microglobulin creatinine was no different (P=0.53), Molina stated.
The patients on the study drug showed small improvements in bone mineral density, but the difference at the spine (P=0.33) and at the hip (P=0.42) were not statistically significantly different, the researchers reported.
Molina said that the results suggest clinicians may be able to prescribe either of these treatments, without need for these routine tests for kidney and liver function “or at least these tests would not have be be ordered as mandatory as has been the case in the past. These are very clean drugs,” he told MedPage Today.
CROI press conference moderator Diane Havlir, MD, of the University of California at San Francisco, said the findings give “options when we are sitting in the room with our patient — even if they are doing okay on their regimen — that there could be something that works better for them. That is the main finding of this study, which shows an advance in antiretroviral therapy.”
The study was sponsored by Gilead Sciences. Some co-authors are company employees.
Molina disclosed relevant relationships with Gilead Sciences, Merck, and ViiV.
Havlir disclosed no relevant relationships with industry.