Dificid, a newer antibiotic for treating Clostridium difficile infection, was highly effective for treating initial and recurrent infections, including in patients with inflammatory bowel disease, according to the results of a multicenter retrospective study.
“The overall response rate to [Dificid (fidaxomicin, Merck)] was 90%,” Sahil Khanna, MBBS, of the division of gastroenterology and hepatology at the Mayo Clinic in Rochester, Minn., told Healio Gastroenterology. “Patients with no prior CDI episodes had significantly higher response and lower recurrence rates compared with patients with prior episodes. All patients with IBD responded to fidaxomicin, with 19% experiencing recurrence, similar to the response and recurrence rates seen in our non-IBD population.”
Because real-world data on fidaxomicin are limited, Khanna and colleagues reviewed a diverse cohort of patients with CDI who were treated with fidaxomicin at Mayo Clinic sites between August 2011 and July 2015. They included 81 patients with a median age of 55.9 years; 53% were women, 26% had IBD, 75% had prior CDI episodes (median, 1), 90% were previously treated with metronidazole, 89% were previously treated with vancomycin, and five patients were previously treated with fecal microbiota transplantation (FMT).
Overall, 90% of patients had complete response to treatment, while 10% had no response. Responders had a median of 1 prior CDI episode while nonresponders had a median of 2.5 (P = .01). The response rate was 100% in patients with an initial CDI episode, 96% in patients with one previous episode, and 82% in patients who had two or more previous episodes (P = .02).
“Our overall response rate was comparable to the response rates reported in phase 3 clinical trials of fidaxomicin,” Khanna said. “However, when we limited our cohort to a population similar to those used in the clinical trials (patients with 0 or 1 prior CDI episodes), the response rate was higher at 98%.”
Overall, 19% of patients experienced recurrence of CDI within 8 weeks after the end of treatment, and patients without recurrence had a median of 1 previous CDI episodes while patients with recurrence had a median of 2 previous CDI episodes (P = .005). No patients with initial CDI experienced recurrence compared with 23% of patients with one previous episode and 29% of patients with at least two previous episodes (P = .005). All IBD patients responded, and 19% experienced recurrence, and four of the five FMT patients responded with one experiencing recurrence.
No adverse events with fidaxomicin occurred.
“We report a higher recurrence rate than seen in the trials, which was to be expected given that almost half of our population had two or more prior CDI episodes, putting them at higher risk of recurrent disease, likely due to decreased microbial diversity in patients previously treated with less selective antibiotics for prior CDI episodes,” Khanna said.
These results suggest that early use of fidaxomicin may be more beneficial than later use in the CDI course, but more real-world studies are needed, Khanna and colleagues concluded. – by Adam Leitenberger
Disclosures: The study was supported by Merck. Khanna reports he serves as a consultant for Rebiotix, and another researcher reports he has served as a consultant for Merck.