Emerging integrase resistance in an international perinatal virtual clinic

Abstract

Objective: The aim of this study was to identify the prevalence of emergent integrase drug resistance mutations (INSTI-DRMs) in international referrals to a perinatal virtual clinic (PVC).

Design: A retrospective cohort study.

Setting: Monthly multidisciplinary PVC reviewing complex case management for children and adolescents with perinatally acquired HIV (CAWHIV).

Participants: One hundred fourteen cases referred for virological failure between October 2018 and January 2024.

Main outcome measures: Data collected included age, sex, weight, country of residence, antiretroviral therapy (ART) history, HIV viral load, CD4+ cell count, and comorbidities. Resistance mutations were interpreted using the Stanford HIV Drug Resistance database with emergent major INSTI-DRMs described.

Results: Of 114 referrals, 103 (90%) had resistance sequences available. Prior INSTI exposure was documented in 61/103 (59%) with 19/61 (31%) having INSTI-DRMs. For these 19, median (IQR) age was 11 years (6-14), weight 25 kg (17-50), CD4+ cell count 485 cells/μl (153-805), and viral load 84 000 copies/ml (2380-137 000). Twelve of 19 (65%) were from low/middle-income countries (LMIC), 6/19 (32%) had current AIDS diagnoses with 14/19 (74%) referred from 2022 onwards. There were a median three prior regimens with 13/19 (68%) having at least 3 class resistance. Two developed INSTI-DRMs on first-line dolutegravir (DTG)-based ART, 17 on second+ line therapy. PVC recommendations were for tenofovir+ lamivudine/emtricitabine (six split adult tablets) with boosted darunavir [19; six twice daily (b.i.d.)], with b.i.d. DTG (6), plus fostemsavir (1) and ibalizumab (1).

Conclusion: Although uncommon, INSTI resistance is emerging, mainly in highly treatment experienced CAWHIV from LMIC, highlighting the global need for access to boosted protease inhibitors and novel classes, including formulations for children less than 35 kg.