Failure of on-demand pre-exposure prophylaxis: the risk of HIV drug resistance

Dear Editor, A man aged 32 years who self-described as men who have sex with men (MSM) started on-demand pre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir (FTC/TDF) based on reporting 30 partners within the last 24 weeks, not using condoms in 50% of sex acts, use of gamma-hydroxybutyric acid during sex and previous STI diagnoses (Smith score=37).1 Over 1 year, we conducted 3-monthly STI screening and HIV-RNA testing. He tested HIV-negative at months 0, 3, 6 and 9. At month 12, he reported missing a single PrEP dose 1 month earlier due to gamma-hydroxybutyric acid use; we formed the impression that more doses might have been missed. Laboratory tests showed detectable HIV-RNA (1938 copies/mL), a positive fourth-generation HIV antibody/antigen test, a negative Alere Determine HIV-1/2 test and a positive western blot (Fiebig stage V),2 together with asymptomatic anal gonorrhoea. The CD4 count was 949 cells/µL. Hepatitis B and C were...
Source: Sexually Transmitted Infections - Category: Sexual Medicine Authors: Tags: PostScript Source Type: research