Virologic Failure and Drug Resistance After Programmatic Switching to Dolutegravir-based First-line Antiretroviral Therapy in Malawi and Zambia

Veronika Whitesell Skrivankova, Jacqueline Huwa, Guy Muula, Geldert D. Chiwaya, Esau Banda, Shameem Buleya, Belinda Chihota, Joseph Chintedza, Carolyn Bolton, Hannock Tweya, Thokozani Kalua, Stefanie Hossmann, Roger Kouyos, Gilles Wandeler, Matthias Egger*, Richard j Lessells*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Background
People with human immunodeficiency virus (PWH) on first-line, nonnucleoside reverse-transcriptase inhibitor–based antiretroviral therapy (ART) were routinely switched to tenofovir-lamivudine-dolutegravir. We examined virologic outcomes and drug resistance in ART programs in Malawi, where switching was irrespective of viral load, and Zambia, where switching depended on a viral load <1000 copies/mL in the past year.

Methods
We compared the risk of viremia (≥400 copies/mL) at 1 and 2 years by viral load at switch and between countries using exact methods and logistic regression adjusted for age and sex. We performed HIV-1 pol Sanger sequencing on plasma samples with viral load ≥1000 copies/mL.

Results
A total of 2832 PWH were eligible (Malawi 1422, Zambia 1410); the median age was 37 years, and 2578 (91.0%) were women. At switch, 77 (5.4%) were viremic in Malawi and 42 (3.0%) in Zambia (P = .001). Viremia at switch was associated with viremia at 1 year (adjusted odds ratio (OR), 6.15; 95% confidence interval [CI], 3.13–11.4) and 2 years (7.0; 95% CI, 3.73–12.6). Viremia was less likely in Zambia than in Malawi at 1 year (OR, 0.55; 0.32–0.94) and 2 years (OR, 0.33; 0.18–0.57). Integrase sequencing was successful for 79 of 113 eligible samples. Drug resistance mutations were found in 5 PWH (Malawi 4, Zambia 1); 2 had major mutations (G118R, E138K, T66A and G118R, E138K) leading to high-level dolutegravir resistance.

Conclusions
Restricting switching to dolutegravir-based ART to PWH with a viral load <1000 copies/mL may reduce subsequent viremia and, consequently, the emergence of dolutegravir drug resistance mutations.

Clinical Trials Registration
Clinicaltrials.gov (NCT04612452).
Original languageEnglish
Article numberciae261
JournalClinical Infectious Diseases
Early online date7 Jun 2024
DOIs
Publication statusE-pub ahead of print - 7 Jun 2024

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