Bausch Health’s New Rifaximin Formulation Fails Phase III Trials

Bausch Health’s updated Xifaxan (rifaximin) formulation, amorphous-rifaximin solid soluble dispersion (SSD), did not meet primary endpoints in two Phase III trials for hepatic encephalopathy (HE), marking a setback for the company. The placebo-controlled studies, RED-C-3131 and RED-C-3132, involved over 1,000 patients across 17 countries and assessed whether rifaximin SSD could delay the first HE episode in adults with liver cirrhosis. Both trials showed no significant improvement over placebo.

Following the announcement, Bausch’s stock fell more than 10%, from $6.57 to $5.91. CEO Thomas Appio said the company will continue reviewing trial data to explore potential opportunities for the formulation. HE, a severe complication of liver cirrhosis, can cause cognitive impairment and confusion, and no preventive therapies currently exist.

Xifaxan, first approved in 2004, remains Bausch’s top revenue driver but faces patent expiry in 2029. Researchers are exploring alternative approaches for HE, including microbiome therapies, stem cells, and liver support systems.

26-01-2026