Transfer and exploitation of Mosnodenvir and related assets

Dengue fever is the most widespread mosquito-borne viral disease globally, with ~4 billion people at risk of dengue virus infection each year. It heavily impacts (sub)tropical regions and increasingly threatens previously low-risk areas, including the US and Europe. Mosnodenvir is a first-in-class small molecule antiviral drug that inhibits the dengue virus NS3-NS4B interaction, preventing viral replication and achieving pico- to nanomolar in-vitro potency across all four serotypes. This antiviral was discovered by KU Leuven (with the support of the Wellcome Trust) together with Johnson & Johnson (JnJ). It has advanced through Phase 1 studies, with no key safety signals reported, and prophylactic antiviral efficacy has been shown in Phase 2 human challenge studies and an early halted Phase 2 community-based field study showing favorable PK/PD. Mosnodenvir has received U.S. orphan drug status for treatment and fast-track designation for prophylaxis and is protected with a large established patent portfolio. After JnJ's August 2025 decision to terminate the license, as part of a broader strategic shift away from infectious diseases, this project aims to secure the continued clinical development of Mosnodenvir through transfer of data, materials, and know-how from JnJ to KULeuven, maintain IP, and find partners to continue clinical development.