EACS 2023: Switching to daily fixed-dose doravirine/islatravir: 96-week results

1 December 2023. Related: Conference reports, Antiretrovirals, EACS 19 Warsaw 2023.

Simon Collins, HIV i-Base

EACS 2023 included 96-week results from a phase 3 study that randomised 641 participants with undetectable viral load on current ART to either switch to daily DOR/ISL (100 mg / 0.76 mg) or continue on B/F/TAF (Biktarvy).

This was a double-blinded placebo-controlled study for the first 96 weeks and continues for a further 48 weeks using open-label fixed dose combinations.

Baseline characteristics included mean age 47.8 years (SD: ±12.2), 72% male, 75% white.

At week 96, viral load was <50 copies/mL in 84.8% vs 90.9% in people taking DOR/ISL vs B/F/TAF (difference –6.1% [95% CI –11.3 to –1.1]). However, when excluding 13 participants from the DOR/ISL arm due to protocol-defined CD4 decreases >30% (introduced at week 72), results were 88.3% vs 90.9% respectively (difference –2.6% [95% CI: –7.5 to +2.2]).

Two participants taking DOR/ISL had viral failure (confirmed >200 copies/mL) at roughly 800 and 14,000 copies/mL, both with no detectable islatravir levels suggesting non-adherence. A single blip to 70 copies/mL in the B/F/TSF arm resuppressed without any changes.

Mean CD4 count changes were lower with DOR/ISL vs B/F/TAF (+6 vs +60 cells/mm³).

Adverse events, including infections, were comparable in each arm. More discontinuations on DOR/ISL were linked to the decline in CD4 counts.

Reference

Paredes R et al. Switch to fixed-dose doravirine/islatravir (100/0.75 mg) once daily in adults with HIV-1 virologically suppressed on bictegravir/emtricitabine/tenofovir alafenamide: week 96 results of a phase 3, randomized, double-blind, non-inferiority trial. 19th EACS, 18–21 October 2023, Warsaw, Poland. Oral presentation PS 1.01.
https://eacs2023.abstractserver.com/program/#/details/presentations/396 (abstract)
https://live.allintheloop.net/Agenda/EACS/EACS2023/greenLiveStream/444748/2 (webcast with login)