US FDA approves Asahi Kasei's pritelivir for persistent herpes

The US Food and Drug Administration on Friday approved Asahi Kasei's oral drug pritelivir for treating persistent herpes simplex virus sores in immunocompromised patients who have not responded to other treatments. The drug, acquired by Asahi Kasei from German drugmaker Aicuris in April, works by blocking proteins the herpes virus needs to copy its genetic material, stopping its multiplication. This mechanism allows pritelivir to combat infections resistant to older treatments, which require activation by a viral enzyme before blocking replication. A late-stage trial involving 101 participants showed that sores healed completely within 28 days in 62.7% of patients receiving pritelivir, compared to 34% receiving other treatments like foscarnet, cidofovir, or imiquimod. Commonly reported side effects included headache, diarrhea, nausea, reduced appetite, vomiting, and dizziness. Asahi Kasei previously estimated that pritelivir could serve about 15,000 US patients and generate peak annual sales exceeding $400 million in the mid-to-late 2030s.