ION253

ION253 (previously known as IONIS-JBI2-2.5Rx) is a generation 2.5 antisense oligonucleotide developed by Ionis Pharmaceuticals and Janssen Biotech. It is designed as an orally delivered, locally acting RNA-targeted therapeutic aimed at reducing the production of an undisclosed target in the gastrointestinal (GI) tract. The primary indication under investigation is the treatment of autoimmune diseases affecting the GI tract. The drug employs RNA interference to silence gene expression, providing a targeted approach for modulating specific proteins involved in GI autoimmune pathologies. As of May 2025, its highest development status is Phase 2[PENDING], and development is led by Janssen for global regulatory and commercialization activities[1][4][11].