Safety and effectiveness of switch to bictegravir/emtricitabine/tenofovir alafenamide following dual regimen therapy in people with HIV: Insights from the Icona cohort.

OBJECTIVES

Most treatment switches are for simplification from three-drug (3DR) to dual regimens (2DR). However, a proportion of people with HIV may switch back to 3DR, like bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) after 2DR.

METHODS

We included people with HIV enroled in the Icona cohort who switched to B/F/TAF after 2DR INSTI-based (3TC/DTG, RPV/DTG, RPV/CAB, or DOR + DTG). Virological rebound (VR), virological suppression (VS), and treatment discontinuation (TD) due to toxicity or failure were evaluated using Kaplan-Meier curves. Random intercept and slopes before and after the switch were used to evaluate the trajectories of triglycerides, cholesterol, CD4, and CD4/CD8. Viro-immunological analyses were stratified according to HIV-RNA at switch.

RESULTS

Among the 3662 people with HIV who started a 2DR INSTI-based regimen, 71 (1.9%) switched to B/F/TAF; 60 had been followed up after the switch, for a median of 10.9 months (interquartile range: 3.6-24.7). Forty people with HIV switched with HIV-RNA <50 copies/mL (uVL), 20 with HIV-RNA ≥50 copies/mL (dVL). Among the uVL group, one participant experienced VR (HIV-RNA: 99, 71 followed by 29 copies/mL). Among the dVL group, the 1-year cumulative probability of undetectable VL was 75% (95% confidence interval [CI] 57.6-95.1). Fourteen people with HIV interrupted B/F/TAF for simplification (50.0%), toxicity (28.6%), VR (14.2%), and patient's choice (7.1); the 1-year cumulative probability of TD for toxicity/failure was 10.7% (95% CI 14.5-24.5). We observed an increase in the CD4/CD8 ratio (+0.02 CD4/CD8/month, p = 0.026) only in the dVL group.

CONCLUSIONS

Switching from 2DR-INSTI to B/F/TAF is infrequent; this switch results in a low rate of toxicity and failure, along with a favourable immunovirological and lipid profile. CD4/CD8 gain is observed in those switching with detectable HIV-RNA.