Alfasigma Secures Exclusive Rights from Innovative Molecules to Parenteral Adibelivir for Treatment of HSV Encephalitis, an Ultra-Rare Disease

Bologna/Munich, January 13 2026 – Alfasigma S.p.A. (“Alfasigma”), a global pharmaceutical company, and Innovative Molecules GmbH (“Innovative Molecules”), a clinical-stage biotechnology company, today announced a strategic partnership whereby Alfasigma will invest in Innovative Molecules and has obtained the exclusive worldwide license to the parenteral formulation of adibelivir (formerly IM 250) for the treatment of Herpes Simplex Virus (HSV) encephalitis, an ultra-rare and life threatening condition.

Adibelivir is a next generation helicase-primase inhibitor. The oral formulation is advancing toward Phase 2 development for genital herpes, while the parenteral formulation is dedicated exclusively to HSV encephalitis and has received approval to enter Phase 1 clinical development.

Clinical Rationale and Patient Impact

HSV encephalitis is a clinically devastating neurological disease, associated with high mortality and a substantial risk of permanent neurological impairment among survivors. Despite decades of use, existing antiviral therapies have not meaningfully improved outcomes, highlighting a critical unmet medical need and a lack of therapeutic innovation in this indication.

Adibelivir is a long-acting helicase inhibitor and is being investigated for its potential to improve viral control and impact clinical outcomes, including survival and long-term neurological sequelae. Although the incidence is low - estimated at 1 case per 250,000 - 500,000 individuals -the disease burden is profound, underscoring the urgent need for innovative treatments capable of improving outcomes in this severe and life-threatening condition.

Francesco Balestrieri, CEO of Alfasigma, commented: “With a focus on rare and specialty care, at Alfasigma we aim to drive growth by developing and delivering innovative solutions that address complex healthcare needs. We are well positioned to do so through our capabilities, expertise, and global footprint. Adibelivir is exactly the kind of innovation we seek to develop and deliver to improve patient outcomes.”

Florian Vogel, CEO of Innovative Molecules, added:

“This partnership represents a strong external validation of our differentiated approach to treating HSV infections and underscores the significant clinical and commercial potential of adibelivir. We are pleased to welcome Alfasigma as a new investor in our company, as this capital infusion will accelerate the advancement of the oral formulation of adibelivir into a Phase 2 clinical development program for patients with genital herpes.”

Financial Considerations

Under the agreement, Alfasigma obtains exclusive global rights to develop, manufacture, and commercialize the parenteral formulation of adibelivir for HSV encephalitis. Innovative Molecules retains full rights to all other formulations, including the oral formulation. Financial terms include payments of up to €125 million in upfront and milestone payments, triggered by development progress, regulatory approvals, and global commercial milestones.