c difficile

FDA Expands Indication for C diff Treatment

The Food and Drug Administration (FDA) has expanded the approval of Dificid (fidaxomicin) for the treatment of Clostridioides (formerly Clostridium) difficile-associated diarrhea (CDAD) in children aged 6 months and older.

The expanded approval is based upon the results of a phase 3, multicenter, investigator-blind, randomized, parallel group study which examined the safety and efficacy of Dificid in patients aged 6 months to >18 years with confirmed C. difficile infection. Of the 148, 142 received either Dificid or vancomycin in a 2:1 ratio. Overall, sustained clinical response (no CDAD recurrence through 30 days following treatment) was higher in the Dificid group than in the vancomycin group (68.4% vs 50,0%).

The safety of Dificid in patients aged 6 months to >18 years was evaluated in a phase 2 single-arm trial involving 38 patients and a phase 3 randomized, active-controlled trial involving 98 patients treated with Dificid and 44 patients treated with vancomycin. Treatment discontinuation due to adverse reactions occurred in 7.9% of patients in the phase 2 trial and 1% and 2.3% of those in the phase 3 trial treated with Dificid and vancomycin, respectively.

The most common adverse reactions in the phase 3 trial were pyrexia, abdominal pain, vomiting, diarrhea, constipation, increased aminotransferases, and rash. A single death occurred in the phase 3 trial in Dificid-treated patients and appeared to be related to underlying comorbidities. No deaths occurred in vancomycin-treated patients.

—Michael Potts

FDA approves merck’s dificid® (fidaxomicin) to treat Clostridioides difficile in children aged six months and older [press release]. Kenilworth, New Jersey: Merck; January 27, 2020. https://www.mrknewsroom.com/news-release/prescription-medicine-news/fda-approves-mercks-dificid-fidaxomicin-treat-clostridioides.