HIV treatment discontinuation less frequent with B/F/TAF than DTG/3TC

In a real-world cohort, virologically suppressed HIV patients who switched from a prior regimen to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) were less likely to discontinue their regimen than those who switched to dolutegravir/lamivudine (DTG/3TC).

“Virologic failure (VF) was infrequent, and no statistical difference was observed in the risk of VF between the two regimens over the study duration,” reported study author Dr Gerald Pierone, Jr from Whole Family Health Center, Vero Beach in Florida, US at IDWeek 2023.

Common single-tablet regimens for HIV

Pierone, Jr's team sought to compare the risk of confirmed VF and risk of regimen discontinuation in virologically suppressed HIV patients in the OPERA* longitudinal cohort who were switching to two common single-tablet regimens for HIV.

Included were treatment-experienced adults switching to B/F/TAF (n=3,713) or DTG/3TC (n=2,327) between 1 Aug 2020 and 30 June 2022, with a viral load (VL) of <200 copies/mL at the time of switch and >1 viral load during follow-up. [IDWeek 2023, abstract 1023]

Confirmed VF was defined as two consecutive VLs ≥200 copies/mL or regimen discontinuation following a VL of ≥200 copies/mL. A VL of ≥50 copies/mL was used in the sensitivity analysis.

Discontinuation was defined as any regimen modification or a treatment gap >45 days. Incidence rates of VF and discontinuation (Poisson regression) and hazard ratios (Cox proportional hazard models) were estimated with inverse probability of treatment weights (IPTW) to adjust for race, payer type, baseline CD4 count, and eGFR decline. Covariate balance was assessed with standardized mean differences. Values more than 0.10 indicated adequate balance.

Those on B/F/TAF were followed for a median of 16 months (interquartile [IQ] range 11–22), whereas those on DTG/3TC were followed for a median of 15 months (IQ range 10–21). Patients were followed up through regimen discontinuation, loss to follow-up, death, or December 2022.

“B/F/TAF was more likely to be prescribed to Black patients who experienced VF on their previous HIV regimen, with lower CD4 counts, and higher eGFR,” reported Pierone, Jr.

Risks of confirmed VF, regimen discontinuation

Key characteristics differed between groups and balance was achieved with IPTW. VF≥200 incidence rates per 100 person-years were low in both groups (B/F/TAF=1.7 and DTG/3TC=2.1). The risk with B/F/TAF was not statistically different from DTG/3TC (HR, 0.84, 95 percent confidence interval (CI), 0.59–1.18), he added.

VF≥50 incidence rates were higher, but the risk did not differ between groups (HR, 1.04, 95 percent CI, 0.86–1.26].

All-cause regimen discontinuation was less likely with B/F/TAF than DTG/3TC (HR, 0.83, 95 percent CI, 0.73–0.94).

Discontinuation due to treatment-related reasons (ie, last VL ≥200 copies/mL, adverse diagnosis, side effect, laboratory abnormality) was identified in 6 percent of B/F/TAF and 9 percent of DTG/3TC recipients. Other reasons for discontinuation were switch to long-acting regimen, pregnancy, access issues, ≥45 days without ART, and patient or provider choice.

“Both regimens were virologically effective. Regimen discontinuation occurred statistically earlier with DTG/3TC than B/F/TAF. Additionally, there were more treatment-related discontinuations with DTG/3TC than B/F/TAF,” Pierone, Jr said.

“Most discontinuations in both groups appeared unrelated to treatment effectiveness or to safety/tolerability events severe enough to be noted in the electronic health record,” he added. “Switching to long-acting antiretroviral therapy was more frequent with DTG/3TC than B/F/TAF.”