Viral kinetics in semen with different antiretroviral treatments


In a randomized open-label study the viral decay in semen was compared between three different antiretroviral regimens. Treatment-naïve HIV-positive men with plasma viral loads between 1,000 and 100,000 copies/ml and seminal plasma level > 1,000 were included in the study. All patients received a backbone treatment with tenofovir disoproxil fumarate plus emtricitabine and either cobicistat-boosted elvitegravir (EVG), rilpivirine (RPV) or ritonavir-boosted darunavir (DRV). Viral load was measured in plasma and seminal plasma at baseline and after 1, 2, 4, 6, 8, 12, 18 and 24 weeks. In seminal fluid, the viral decay rate was similar for EVG and RPV while the decay was slower with DRV. After 12 weeks of therapy all patients receiving EVG and RPV had undetectable viral load in seminal plasma but only 58 % in the DRV arm. Drug concentrations were measured in plasma and seminal plasma. The concentration ratio between seminal plasma and plasma was 0.43 for EVG, 0.19 for RPV and 0.10 for DRV.

Gutierrez-Valencia et al. Clin Infect Dis 2017;65:551-556

Comment: It is somewhat surprising that the viral decay in seminal plasma is as rapid with RPV as with EVG taken the faster plasma decay with EVG (like all integrase inhibitors) into account. It is less surprising that the viral decay is slower with DRV. It has been shown repeatedly that protease inhibitors have a slower viral decay compared to non-nucleoside reverse transcriptase inhibitors and integrase inhibitors. It is uncertain whether these results should have any clinical consequences.