The treatment of choice for acyclovir-resistant HSV is IV foscarnet (AI).38,39 IV cidofovir is a potential alternative (CIII). A novel agent, the helicase-primase inhibitor pritelivir, is currently being testing in clinical trials for treatment of acyclovir-resistant herpes in immunocompromised persons (ClinicalTrials.gov Identifier: NCT03073967). There is an Expanded Access Program available for oral pritelivir in these populations; for more information see AiCuris Pritelivir website. Topical trifluridine, foscarnet, cidofovir, and imiquimod also have been used successfully to treat external lesions, although prolonged application for 21 days to 28 days or longer may be required (CIII).40-44