FDA approves antibiotic for CDAD, oral treatment for hepatitis C infection

Key Points

Fidaxomicin

(Dificid, Optimer Pharmaceuticals)

Efficacy. Fidaxomicin's efficacy was demonstrated in 2 randomized, active-controlled, double-blind trials enrolling a total of 564 adult patients with CDAD. Both trials compared fidaxomicin 200 mg twice daily for 10 days to vancomycin 125 mg 4 times daily for 10 days. Enrolled patients had either no prior history or only 1 episode of CDAD in the previous 3 months and were not suffering from a life-threatening or fulminant infection. At the end of the 10-day treatment course, clinical response was similar between the fidaxomicin and vancomycin groups. Additionally, the sustained clinical response rate (25 days after the end of treatment) showed fidaxomicin to be superior to vancomycin.

Safety. The safety of fidaxomicin was evaluated in the 2 trials mentioned above. The most common adverse reactions noted in these trials were nausea, vomiting, abdominal pain, gastrointestinal hemorrhage, anemia, and neutropenia. Thirty-three patients receiving fidaxomicin withdrew from the study because of an adverse reaction. Vomiting was the most common adverse reaction to result in fidaxomicin (and vancomycin) discontinuation.

Dosing. The recommended dose is one 200-mg tablet taken twice daily with or without food. No dose adjustment for fidaxomicin is required in patients with renal dysfunction. The impact of hepatic dysfunction on the pharmacokinetics of fidaxomicin has not been evaluated, but since the drug and its metabolites do not undergo hepatic metabolism, no dose adjustment is expected.