Switch to B/F/TAF sustains virologic suppression in adult PLHIV

Adult people with HIV-1 (PLHIV) who switched to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) after initially taking dolutegravir/abacavir/lamivudine (DTG/ABC/3TC) or DTG+F/TAF show a consistently high virologic suppression and have few discontinuations over 5 years of follow-up, according to a study presented at the HIV Glasgow 2022 Congress.

“HIV guidelines offer switch strategies for virologically suppressed PLHIV, but long-term clinical follow-up after the regimen switch is often lacking, said the researchers led by Chloe Orkin, physician and professor of HIV Medicine at Queen Mary University London, UK.

Orkin and her team assessed 96-week outcomes on B/F/TAF in an open-label extension that followed 144 weeks of blinded DTG-based treatment in two randomized, double-blind phase III studies of PLHIV initiating first-line treatment: study 1489 (n=254; B/F/TAF vs DTG/ABC/3TC) and study 1490 (n=265; B/F/TAF vs DTG+F/TAF). [HIV Glasgow 2022, abstract P088]

The researchers then examined the cumulative results for PLHIV who were initially treated with either DTG/ABC/3TC or DTG+F/TAF for 144 weeks and then switched to 96 weeks of B/F/TAF in an open-label extension (total of 240 weeks of follow-up). They also assessed efficacy as the proportion with HIV-1 RNA <50 copies/mL at each visit after initiating B/F/TAF (missing=excluded [M=E] analysis) and safety by adverse events (AEs) and laboratory results.

In the first study, 315 PLHIV were randomized to DTG/ABC/3TC, of whom 254 (81 percent) entered the open-label extension. In the second study, 325 participants were randomly assigned to DTG+F/TAF, of whom 265 (82 percent) entered the extension phase.

M=E analysis revealed greater than 96-percent efficacy at every visit through week 240 following the switch to B/F/TAF. Eleven PLHIV had HIV-1 RNA ≥50 copies/mL at time of switch, of whom two were found to have M184V while on blinded DTG/ABC/3TC and resuppressed on B/F/TAF.

“No resistance to any components of B/F/TAF occurred in any group of the final resistance analysis population,” the researchers noted.

In terms of safety, two out of 519 (0.4 percent) switch participants across both studies had an AE that resulted in treatment discontinuation during the open-label extension. No discontinuations due to renal AEs were reported. Grade 3 drug-related AE occurred in one participant, but none had grade 4 AEs.

Of note, small median fasting lipid changes occurred from time of switch to B/F/TAF to the open-label extension at week 96. PLHIV who switched from DTG/ABC/3TC had greater weight increases than those who switched from DTG+F/TAF.

“These results provide additional long-term evidence of the safety and efficacy of B/F/TAF in those who switch from a DTG-containing regimen,” the researchers said.

Another study presented at the HIV Glasgow 2022 Congress reported the safety and efficacy of B/F/TAF in older PLHIV with a long history of HIV infection, several comorbidities, and comedication. Twenty-seven participants were enrolled in eight French clinical centres, of whom 91.7 percent maintained a plasma viral load of <50 copies/mL at week 24. [HIV Glasgow 2022, abstract P038]