B/F/TAF maintains viral suppression through 4 years in HIV patients

Treatment with the single-tablet regimen of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) leads to sustained viral suppression through 4 years with no treatment-emergent resistance in treatment-naïve people living with HIV (PWH), according to a long-term study presented at IAS 2021.

“B/F/TAF is a guideline-recommended single-tablet regimen for PWH,” stated lead author Dr Jose Ramon Arribas of Hospital Universitario La Paz in Madrid, Spain, who noted that B/F/TAF has been shown to be noninferior to dolutegravir/abacavir/lamivudine (DTG/ABC/3TC) and DTG+F/TAF in treatment-naïve PWH in previous studies, up to week 144.

The current study followed 506 PWH (median age 32 years, 89 percent male) who were originally assigned to receive B/F/TAF in two double-blind phase III randomized studies for 144 weeks and opted to continue participating in the open-label extension (OLE) phase thereafter, in which all patients were offered B/F/TAF. [IAS 2021, abstract PEB 151]

At week 192, almost all participants on treatment with B/F/TAF (99.2 percent) still maintained viral suppression, defined as HIV-1 RNA <50 c/mL, with their CD4 count increasing by a median of 289 cells/mL from baseline.

There were no reports of treatment failure due to treatment-emergent resistance.

In terms of safety profile, most of the treatment-emergent adverse events (AEs, 79 percent) were of grade 1 or 2, with the most common being diarrhoea, nasopharyngitis, upper respiratory tract infection, headache, and syphilis. Discontinuation due to AEs was rare, occurring in 1 percent of the participants. 

In addition, these participants saw a median weight gain of 4.9 kg at 192 weeks compared with baseline, which according to the researchers, occurred mostly during the first year of treatment (at 3 kg gain). 

“Through 4 years of follow-up, B/F/TAF resulted in high rates of virologic suppression with no treatment-emergent resistance, and a low frequency of AEs and few drug discontinuations,” Arribas concluded.

High suppression in older people

High rate of viral suppression was also maintained through 96 weeks in older PWH (≥65 years) who had switched to B/F/TAF from previous regimen, as shown in a separate international, phase III b, open-label trial. 

Participants in this study were 86 virologically suppressed (viral load <50 copies/mL) PWH aged ≥65 years (median age 69 years, 13 percent female) who switched to B/F/TAF from their baseline treatment of either E/C/F/TAF* or a TDF**-based regimen. [IAS 2021, abstract PEB 160]

At 96 weeks, all participants had sustained viral suppression among the 64 participants (74 percent) with virologic data available. The remaining 26 percent did not have virologic data available within the week 96 window. No virologic failures were detected and median CD4 counts remained stable at 96 weeks.

Grade 3-4 study drug-related AEs occurred in 2.3 percent of patients and grade 3-4 laboratory abnormalities in 13 percent of patients. Three participants (3.5 percent) discontinued treatment due to AEs — none of which was attributed to renal, bone or hepatic AEs.

“The safety and efficacy data support the switch to B/F/TAF in virologically suppressed, HIV-infected individuals aged ≥65 years,” said the researchers. 

*E/C/F/TAF: Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide

**TDF: Tenofovir disoproxil fumarate