Search

Rilpivirine (RPV) and Etravirine (ETR) are approved second-generation non-nucleoside reverse transcriptase inhibitors (NNRTIs) for HIV treatment. There is a cross-resistance HIV mutation profile between first- and second-generation NNRTI drugs. We determined the prevalence of HIV-1 drug resistance mutations (DRMs) to RPV and ETR in Botswana. A total of 168 HIV-1 polymerase gene sequences from participants failing nevirapine (NVP)- or efavirenz (EFV)-containing regimens were analyzed for DRMs using the Stanford University HIV drug resistance database. Forty-one sequences were from an adult antiretroviral therapy (ART) study, the Tshepo study, and 127 from a prevention of mother-to-child transmission (PMTCT) study, the Mashi study, all conducted in Botswana. Prevalence of RPV and ETR highest DRM in the adult ART study (n = 41) were K101E (26.2%), E138A (23.8%), and Y181C (26.2%). The PMTCT cohort's (n = 127) high prevalence mutations were Y181C (15.7%), E138A (15%), and K101E (11%). A total of 42.9% and 3.2% of patients in the adult ART study and PMTCT study, respectively, had three or more NNRTI mutations at virologic failure. We identified HIV-1 mutations conferring resistance to RPV and ETR even though they have not been used in Botswana. Of concern was the high proportion of sequences from the adult ART study that displayed multiple DRMs; as the number of NNRTI mutations increases, the level of cross-resistance increases. It is plausible that patients displaying such profiles maybe at increased risk of failing second-generation NNRTI drugs, hence, calls for genotyping in patients with prior NVP or efavirenz exposure before prescription of RPV- or ETR-containing cART.

HIV-1 uses the coreceptors CCR5 and/or CXCR4 for cell entry. Monotropic CCR5-using variants are found early in the infection while CXCR4-using variants may appear after progression to AIDS. CXCR4 use may consist of both monotropic and dualtropic viruses. The viral phenotype is important in evaluating the response to CCR5 inhibitors, a new class of antiviral drugs. The coreceptor use of HIV-1 was investigated using population sequencing in 24 patients from Botswana, carrying HIV-1 subtype C and failing antiretroviral treatment, while 26 treatment-naive patients acted as controls. Single genome sequencing was used to discern minor HIV-1 populations in the treatment-experienced group. The Geno2Pheno method was employed to predict the coreceptor use phenotype from HIV-1 env gp120 V3 DNA sequences. The glycan-charge model adjusted for subtype C was also used for phenotype prediction. The viral phenotype of population sequences was predicted using Geno2Pheno in 24/24 treatment-experienced patients, of whom eight (33%) were predicted to harbor CXCR4-using strains as compared to 2/26 in the treatment-naive group (p=0.03). Single genome sequencing generated 4-23 clones/patient in the treatment-experienced group. Altogether, 90/295 (31%) putative CXCR4-using clones were identified. In 10/24 (42%) treated patients at least one clone was predicted to be CXCR4-using, further increasing the amount of identified treatment-experienced patients with CXCR4 use. Although subtype C is usually associated with comparatively little CXCR4 use, the frequency of CXCR4 use in treatment-experienced patients with subtype C can be higher, which may have implications for the administration of CCR5 inhibitors in this patient group.