The FDA has approved pritelivir (Hovilpri) as an oral treatment for mucocutaneous herpes simplex virus (HSV) lesions in immunocompromised patients whose infections have not responded to existing therapies. Pritelivir is a helicase-primase inhibitor, a mechanism distinct from the nucleoside analogues and foscarnet commonly used, and it is active against HSV-1 and HSV-2 strains resistant to those drugs.
In the open-label phase III PRIOH-1 trial, 101 immunocompromised patients with refractory HSV infection were assigned to take 100 mg pritelivir once daily or to receive an investigator-chosen comparator among foscarnet, cidofovir, or imiquimod. By day 28, 63% of the pritelivir group had all lesions healed, compared with 34% of the comparator group. The trial included patients with a wide range of immunosuppressive conditions, including hematologic malignancies, stem-cell transplantation, HIV infection, autoimmune or inflammatory diseases, nonhematologic malignancies, and solid-organ transplantation.
Rapid lesion healing and tolerability are essential for this population, according to Aicuris chief medical officer Cynthia Wat. Headache was the most common adverse reaction observed in the pritelivir arm. The approval provides a new oral option for a difficult-to-treat condition, though HSV infection itself remains incurable.