FDA Approves Hovilpri for Drug-Resistant HSV Lesions in Immunocompromised Adults

The U.S. Food and Drug Administration has authorized Hovilpri for use in adults with mucocutaneous herpes simplex virus lesions that do not respond to standard antiviral treatments. This approval applies specifically to immunocompromised patients whose infections are resistant to acyclovir, valacyclovir, or famciclovir.

Asahi Kasei Therapeutics announced the FDA decision on October 9, 2026, describing Hovilpri as the first new HSV therapy with a distinct mechanism in nearly three decades. The company stated that the drug operates differently from existing nucleoside analogue treatments.

Hovilpri is classified as a helicase-primase inhibitor, which sets it apart from previously approved antiviral medications for herpes simplex virus. According to the company, this mechanism targets the virus in a way that is not addressed by nucleoside analogues.

The FDA granted Hovilpri priority review status, which is reserved for drugs that may offer significant improvements over existing therapies. This designation can expedite the review process for medications that address unmet medical needs.

What the numbers show

• 63% of immunocompromised adults treated with Hovilpri achieved complete lesion healing by Day 28.
• 34% of patients receiving investigator’s choice treatment reached complete healing in the same period.
• Hovilpri is the first HSV therapy with a novel mechanism approved in nearly 30 years.

In the Phase 3 PRIOH-1 Part C clinical trial, Hovilpri demonstrated higher rates of lesion healing compared to other available treatment options. The trial included immunocompromised adults with HSV lesions that were resistant to commonly used antivirals.

Results from the study showed that a greater proportion of patients receiving Hovilpri experienced full healing of their lesions within 28 days, compared to those treated with alternatives selected by investigators. These findings supported the FDA's decision to approve the drug for this specific patient group.

Hovilpri's approval provides a new therapeutic option for individuals with limited alternatives due to resistance to standard antiviral medications. The FDA's action reflects a documented need for treatments that address drug-resistant HSV infections in immunocompromised adults.

* This article is based on publicly available information at the time of writing.