R-1206 (also known as Elsulfavirine) is a phenylacetamide derivative patented by Roche Palo Alto LLC as non-nucleoside reverse transcriptase inhibitor (NNRTI) for treating retroviral infections. R-1206 is the prodrug of the active compound VM-1500A, a small molecule selective NNRTI, which prevents HIV replication. The antiviral activity of R-1206 is broad, with activity demonstrated towards various viral strains and clinical isolates of HIV, including those resistant to other NNRTIs. Furthermore, R-1206 was associated with a low probability of cross-resistance or resistance development, and a high genetic barrier to the development of resistant drug mutations. In clinical trials, R-1206 20 and 40 mg demonstrated superiority to efavirenz in terms of the effectiveness to reduce the level of viral load to 400 copies/mL after 12 weeks of therapy. R-1206 20 mg once daily is generally well tolerated in ART-naive HIV-1 infected patients.