Asahi Kasei’s AiCuris buyout pays off with FDA approval for HOVILPRI

Asahi Kasei’s acquisition of German biotech AiCuris for about €780 million ($920 million) brought pritelivir into its portfolio. The drug is now FDA-approved under the brand name HOVILPRI.

The FDA approved HOVILPRI for immunocompromised adults with herpes simplex virus (HSV) skin or mucosal lesions that do not respond to standard antivirals—acyclovir, valacyclovir, or famciclovir—with or without documented resistance.

Pritelivir works through a different mechanism:
it inhibits the HSV helicase-primase enzyme, rather than targeting the virus in the same way as older antivirals. It is an oral option for eligible patients, potentially avoiding intravenous treatment.

In the pivotal Phase 3 study of 101 patients, lesions healed within 28 days in about 63% of those receiving pritelivir, compared with 34% receiving comparator treatments.

The approval is a notable addition for patients whose weakened immune systems—such as after transplantation or because of cancer or HIV—make HSV infections harder to control. U.S. availability was expected before the end of 2026.