ESCMID Global 2026: Pritelivir Excels in Immunocompromised Refractory HSV Patients

Why It Matters

Pritelivir could become the first oral, once‑daily therapy that outperforms IV antivirals for refractory HSV, addressing a critical unmet need in a growing immunocompromised population.

Key Takeaways

• Pritelivir achieved 62.7% lesion healing vs 34% with standard care
• Complete healing by day 48: 82.4% vs 42% for comparators
• Drug‑related adverse events occurred in 21.6% vs 54% with IV therapies
• FDA granted priority review; PDUFA decision expected Q4 2026
• Oral once‑daily dosing simplifies treatment for immunocompromised patients

Pulse Analysis

Herpes simplex virus infections remain a persistent burden, especially for patients with compromised immune systems. Standard antivirals such as acyclovir often fail to clear lesions, forcing clinicians to rely on intravenous foscarnet or off‑label regimens that carry toxicity, administration challenges, and limited efficacy. As cancer therapies and organ transplantation expand, the pool of immunocompromised individuals is growing, intensifying demand for safer, more convenient treatments that can halt severe, refractory HSV disease.

Pritelivir, a first‑in‑class helicase‑primase inhibitor, targets a viral replication complex distinct from nucleoside analogues, preserving activity against acyclovir‑ and foscarnet‑resistant strains. The PRIOH‑1 Phase III trial demonstrated a 28.4‑percentage‑point advantage in complete lesion healing by day 28 (62.7% vs 34%) and an even larger gap by day 48 (82.4% vs 42%). Viral DNA clearance rose to 73.7% with pritelivir versus 48.7% for comparators, while drug‑related adverse events dropped to 21.6% from 54%. These outcomes suggest a superior efficacy‑safety balance, potentially redefining standard care for this high‑risk cohort.

Regulatory momentum is strong: the FDA granted pritelivir priority review in April 2026 and set a PDUFA target for the fourth quarter of the year. An oral, once‑daily regimen could dramatically reduce hospital stays and infusion‑related costs, opening a sizable market as the global immunocompromised population expands. If approved, pritelivir would likely capture a leadership position in refractory HSV therapy, offering clinicians a potent, patient‑friendly alternative that aligns with broader trends toward oral antivirals and personalized infectious‑disease management.