Allschwil, Switzerland – June 1, 2026 Idorsia Ltd (SIX: IDIA) today announced additional positive clinical results for IDOR-1134-2831, its vaccine targeting Clostridioides difficile (C. difficile) in a Phase 1 clinical pharmacology trial. The glycan target of this vaccine is present on both bacteria and spores – the transmissible form of the pathogen responsible for spreading infection – of the most clinically relevant C. difficile strains, including hypervirulent variants. Following initial results in June 2025, which provided the first clinical validation for Idorsia's synthetic glycan vaccine technology, the company advanced the program with a higher-dose cohort.