Sexually transmitted infections in men who have sex with men with tenofovir/emtricitabine- or cabotegravir-resistant HIV

Objective: Sexually transmitted infections (STIs) are associated with an increased risk of HIV transmission, raising concerns in case of virus resistant (R) to the drugs currently approved for pre-exposure prophylaxis (PrEP). We explored the incidence of STIs in men who have sex with men with HIV (MSMWH) and resistance to tenofovir/emtricitabine (TXF/FTC) and/or cabotegravir (CAB). Design: Retrospective, cohort study on MSMWH on antiretroviral treatment (ART) with ≥1 genotyping resistance test (GRT) including integrase. Methods: The following STIs were included in the analysis: Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma/Ureaplasma spp. (only if symptomatic), early syphilis (primary, secondary, or early latent), and mpox infections. Poisson regression modeled incidence rates (IRs) and 95% confidence intervals (95%CIs). Results: Overall, 638 MSMWH evaluated: 67 (10.5%) TXF/FTC-R, 4 (0.6%) CAB-R, and 13 (2.0%) TXF/FTC+CAB-R. During a median follow-up of 9.6 (7.3-11.7) years [5908 person-years-of-follow-up (PY)], 307/638 (48.1%) individuals developed 744 STIs: IR = 12.6 (95%CI = 11.7-13.5)/100 PY. Among 307 MSMWH who developed STIs, 34 (11.1%) had ≥1 STI at HIV load ≥200 copies/mL [21 (6.8%) ≥1000 copies/mL]. Thirty-two (10.4%) of 307 individuals with ≥1 incident STI had TXF/FTC- and/or CAB-R strains; 5 (15.6%) of these developed STIs at HIV load ≥200 copies/mL (specifically, ≥1000 copies/mL). STI incidence was significantly lower in presence of drug resistance [either TXF/FTC- or CAB-R: IR = 8.2 (95%CI = 6.2-10.5)/100 PY and IRR = 0.6 (95%CI = 0.5-0.8); TXF/FTC+CAB-R: IR = 2.9 (95%CI = 0.8-7.3)/100 PY and IRR = 0.2 (95%CI = 0.1-0.5)]. Conclusions: In our cohort of MSMWH, STI incidence was non-negligible, although reduced, in presence of resistance to TXF/FTC and/or CAB. Discussion of HIV resistance test results should include the risk of sexual transmission uncontrolled by pre-exposure prophylaxis.