Fidaxomicin, a macrolide antibiotic, is used for the treatment of Clostridioides difficile infection (CDI). It works by inhibiting bacterial RNA polymerase, leading to the suppression of bacterial protein synthesis and ultimately bacterial cell death. Fidaxomicin is considered to be a highly effective treatment option due to its targeted action within the gastrointestinal tract, minimizing systemic absorption and related side effects. Its activity against C. difficile is superior in terms of both efficacy and reducing recurrence rates compared to other antibiotics like vancomycin.

Fidaxomicin Tablets, 200 mg, are approved under an abbreviated new drug application (ANDA), demonstrating bioequivalence to the reference listed drug (RLD), Dificid Tablets, 200 mg, by Cubist Pharmaceuticals. The approval was granted following a detailed review of the product’s safety and efficacy profile. The tablets are subject to specific patent protections, which include several U.S. patents listed in the FDA's Orange Book, with expiration dates in 2027 and 2028, along with pediatric exclusivity. The approval process also acknowledged the compliance with the FDA's regulatory requirements, including the submission of a paragraph IV certification and successful dismissal of patent infringement litigation.