The Food and Drug Administration (FDA) has approved Dificid (fidaxomicin) for the treatment of Clostridioides difficile-associated diarrhea in adult and pediatric patients aged 6 months and older. Previously, the treatment had only been approved for adults ≥18 years of age. Additionally, an oral suspension formulation of fidaxomicin, a macrolide antibacterial, has also been approved.
The pediatric approval was based on data from the phase 3 SUNSHINE study, which evaluated the clinical response of fidaxomicin vs vancomycin in pediatric patients with C. difficile-associated diarrhea (N=148). The primary end point of the study was clinical response defined in patients <2 years old as the absence of watery stools for at least 2 consecutive days while on treatment with no requirement for further therapy through 2 days after completing treatment. In patients ≥2 to <18 years, clinical response was defined as <3 unformed bowel movements for at least 2 consecutive days while on treatment and no requirement for further therapy through 2 days after completing treatment.
Results from the trial showed clinical response in the overall pediatric population was similar between the fidaxomicin and vancomycin groups (77.6% vs 70.5%; treatment difference: 7.5 [95% CI, -7.4 to 23.9]). Moreover, sustained clinical response, a secondary end point defined as the proportion of treated patients with confirmed clinical response and no C. difficile-associated diarrhea recurrence through 30 days after the end of treatment, was higher for fidaxomicin than for vancomycin (68.4% vs 50.0%; treatment difference: 18.4 [95% CI, 1.5 to 35.3]).
As for safety, the most common adverse reactions in pediatric patients treated with fidaxomicin were pyrexia, abdominal pain, vomiting, diarrhea, constipation, increased aminotransferases and rash.
Dificid is currently available as a 200mg tablet. The oral suspension will be supplied as granules in bottles containing 5.45g of fidaxomicin (40mg of fidaxomicin per mL after reconstitution).
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