Aicuris Reports Positive Phase III Results for Pritelivir in Refractory HSV

Aicuris has announced positive results from its pivotal Phase III PRIOH-I trial evaluating pritelivir in immunocompromised patients with refractory herpes simplex virus (HSV) infections, including resistant disease. The open-label, global study compared pritelivir with investigator’s choice therapy (ICT) and enrolled 101 treated patients, with an additional 56 in a non-randomised cohort.

In October 2025, Aicuris confirmed the trial met its primary efficacy endpoint and demonstrated a favourable safety and tolerability profile. Drug-related treatment-emergent adverse events occurred in 2% of patients receiving pritelivir, compared with 20% in the ICT arm, which included foscarnet, cidofovir or imiquimod.

Pritelivir’s novel mechanism targeting the HSV helicase-primase complex could address long-standing unmet need in patients who fail existing antivirals. The results support pritelivir’s potential to redefine care for high-risk HSV patients.

08-02-2026