Collins AMBE CHENWI1*
1Faculty of Medicine and Biomedical Sciences Yaounde (FMBS-yaounde)
CaHReF 2018, Yaoundé Congres hall, 08 – 11 January 2019 , OSEP047
Background: HIV is a global health priority, with national prevalence of 3.4% in Cameroon and a high genetic diversity. With scale-up of antiretroviral therapy (ART), HIV drug resistance (HIVDR) becomes a public health priority, requiring monitoring of determinants according to ART-regimens, in order to set-up measures to limit resistance emergence nationwide.
Objectif: To determine the threshold of HIVDR according to ART-exposure of non-B HIV-1 subtype infected patients and factors associated with HIVDR emergence within the Cameroonian context.
Methodology: Using the CIRCB-HIVDR database, a study was conducted among patients received for HIVDR testing at the Virology Laboratory of the Chantal BIYA International Reference Centre for Research on HIV/AIDS prevention and management (CIRCB) from January 2011 to May 2017. Briefly, genotypic HIVDR testing was performed in the protease-reverse transcriptase region and interpreted using the Stanford University HIVDR database.v.8.5. BioEdit.v7.0.5.3 (for sequence alignment) and MEGAv7.0.26 (for phylogenetic tree construction). Statistical analyses were performed per group (ART-na'à¯ve, first- and second-line ART-experienced patients), major HIVDR mutations and their association with clinical, immunological and virological parameters were evaluated; p <0.05 considered statistically significant.
Results: Overall, 441 patients were enrolled (mean-age: 41 ±11 years; 61.68% female) and stratified following ART-exposure: 135 ART-na'à¯ve, 199 and 107 failing first- and second-line respectively. Median-CD4 was highest amongst ART-na'à¯ve (206 cells/mm3 [IQR:72-333], vs. 126 cells/mm3 [IQR:55-241] first-line vs. 110 cells/mm3 [IQR:45-150] second-line). Viremia varied similarly: ART-na'à¯ve (180,900copies/ml [IQR:53,400-617,320]); first-line (50,828copies/ml [IQR:5,280-90,756]); second-line (38,000 copies/ml [IQR:10,230-111,596]). HIVDR increased from 8.15% (ART-na'à¯ve), 83.70% (first-line) to 85.98% (second-line), p=0.54. CRF02_AG was prevailing (60.54%) and associated with lower HIVDR-emergence compared to others (50.35% vs. 64.97%; OR:0.55; p=0.003). However, HIVDR-emergence was similar between patients with poor (83.89%) vs. good (82.00%) compliance to ART (OR:0.93; p=0.88).
Conclusion/Recommandation: In Cameroon, immunity decreases from na'à¯ve to first- and second-line ART-experienced patients, with a similar trend in viral replication (likely due to decreased viral-fitness in the frame of increasing mutants with ART-exposure). The predominant CRF02_AG appears to limit HIVDR emergence compared to other strains circulating. Thus, key determinants of HIVDR-emergence in our Cameroonian context entail exposure to failing ART-regimens, delayed detection of treatment failure (i.e. very-low CD4 at failure) and viral subtype.
Key Words: HIV-1 drug Resistance; Determinants; Subtype; Cameroon