Evaluation of HIV drug resistance in virally suppressed patients in Cameroon
BACKGROUND: Viral suppression (Viral load < 1000copies/ml) is considered a therapeutic success in resource limited settings. However, several studies have shown the presence of resistance mutations at residual viral loads, which could compromise long-term therapeutic response. We sought to assess the effectiveness of sequencing and determine the HIV drug resistance genotypic profile in virally suppressed patients (VSP) in Cameroon.
METHODS: A cross-sectional and analytical study was conducted at the Chantal BIYA International Reference Centre from January 2020 to August 2021 among VSP. Sequencing was performed in the reverse-transcriptase and protease regions. Sequences were analysed using the Stanford HIVDBv9.0 algorithm, and molecular phylogeny done using MEGAX. Sequencing success rate and occurrence of drug resistance mutations were assessed by viremia, with P<0.05 considered statistically significant.
RESULTS: In total, 132 participants were retained; median age [IQR]: 43[33-51] years; 69% female. The median duration on antiretroviral therapy (ART) was 19 [12-34.4] months. The amplification rate was 39 (CI95%, 21.93-38.11) %, and the sequencing success rate 28.8% (38/132), thus 97.4% of amplicons. Genotyping was more effective for patients with viremia â?¥ 200 copies/ml, 47.2% (25/53) versus 16.5% (13/79) for viremia â?¤ 200 copies/ml, p<0.001. Of the 38 sequences generated, the overall resistance rate was 89.74%, with 79.9% NRTI resistance, 79.4% NNRTI resistance and 15.3% PI/r resistance. This resistance rate was higher in patients with viremia â?¥ 200 copies/ml, 32.0% versus viremia â?¤ 200 copies/ml (7.7%), OR 5.65; p=0.13. Seven viral clades were identified with predominance of CRF02_AG (64%). M184V (74.3%) and K103N (45.7%) were the most frequent mutations in reverse transcriptase and M46I 14.2% in protease. The viral susceptibility profile revealed 41.1% (14/38) of participants on suboptimal therapies despite virological suppression.
CONCLUSIONS: â??In the Cameroonian context with broad HIV genetic diversity, sequencing appears to be effective in half of the virally suppressed patients with a viremia of at least 200 copies/ml. Moreover, the emergence of major resistance mutations in these patients would be more considerable with a viral load â?¥ 200 copies/ml. In these virally suppressed patients, nearly 4 out of 10 would need to optimise their therapy for long-term therapeutic success.
R.A. Nayang Mundo * (1), J. Fokam (1,2), C. Chenwi (1,2), D. Takou (1), M.-S. Sosso (1), W.L. Pabo Togna (3), A. Ka'e (4), G.O. Beloumou (1), S.C. Djupsa (1), A. Abba (1), C.-F. Perno (1,5)
(1) Centre International de Référence CHANTAL BIYA pour la Recherche sur la Prévention et la Prise en Charge du VIH/SIDA, Virology, Yaoundé, Cameroon, (2) Faculté de Médecine et des Sciences Biomédicales du Cameroun, Microbiology, Yaoundé, Cameroon, (3) Faculty of Science, University of Buea, Buea, Cameroon, (4) University of Rome â??Tor Vergataâ??, Rome, Italy, (5) University of Milan, Milan, Italy