This oral medication is indicated for patients whose infections do not respond, with or without documented resistance, to standard antiviral therapies including acyclovir, famciclovir, or valacyclovir.
The company anticipates that the medicine will become available in the US before this year end.
The regulatory decision followed findings from PRIOH-1 Part C, an open-label, comparator-controlled Phase III superiority trial involving 101 immunocompromised adults.
Patients received either pritelivir or Investigator’s Choice therapy consisting of cidofovir, foscarnet, or imiquimod.
By day 28, complete lesion healing occurred in 63% of patients receiving Hovilpri compared with 34% on Investigator’s Choice, representing an adjusted treatment difference of 28.4%.
By Day 42, response rates reached 82% and 42%, respectively, an adjusted difference of 40.0%.
Safety findings from the trial showed adverse reactions in 22% of pritelivir recipients against 54% in the comparator arm. Discontinuations due to adverse drug reactions occurred in 2% of the Hovilpri cohort versus 20% receiving Investigator’s Choice.
Headache was the most frequent adverse reaction, reported in 6% of HOVILPRI patients and 4% of those receiving Investigator’s Choice.
Asahi Kasei Therapeutics US and Europe CEO Stacy Wheeler said: “Today’s approval delivers the first FDA-approved treatment for refractory mucocutaneous HSV lesions with a novel mechanism of action in nearly 30 years and marks an important advancement for immunocompromised adults.
“Hovilpri offers a new oral treatment option for adult patients with a persistent, difficult-to-treat disease.”
Unlike nucleoside analogues that require viral thymidine kinase enzyme activation, Hovilpri operates as a helicase-primase inhibitor active against both HSV-1 and HSV-2 strains, including those resistant to nucleoside analogues and foscarnet.
The therapy was originated by AiCuris Anti-infective Cures, now part of Asahi Kasei Therapeutics, the global specialty pharmaceutical unit of Tokyo-headquartered Asahi Kasei.
HSV is an incurable, lifelong infection that can cause severe, prolonged complications in immunocompromised people, including transplant recipients, cancer patients, and those living with HIV.
Earlier this month, Asahi Kasei signed a definitive agreement to acquire all issued shares of German-based Aicuris Anti-infective Cures for approximately $920.7m.