1496. Bezlotoxumab Administered at the End of a Suppressive Drug Regimen for Patients with Multiply Recurrent Clostridioides difficile Infection.

Background Recurrent Clostridioides difficile infection (CDI) remains a public health burden, affecting as many as 35% of patients with primary CDI. Bezlotoxumab, a monoclonal anti-toxin B antibody, was the first FDA-approved agent indicated for the prevention of recurrent CDI, but real-world experience is limited, particularly in patients with multiple CDI recurrences. Methods We conducted a retrospective case study of patients with multiple CDI recurrences who failed prior treatments with pulsed and tapered vancomycin and fidaxomicin regimens. Six patients in a single CDI specialty outpatient clinic received a single iv infusion of bezlotoxumab at the end of a suppressive vancomycin or fidaxomicin treatment regimen. The suppressive treatment was stopped immediately after the bezlotoxumab infusion and the patients were followed closely for recurrent symptoms and need for additional CDI treatment. Results Four of 6 patients who received bezlotoxumab at the end of a suppressive treatment regimen did not require subsequent CDI treatment and have been followed for 2 weeks to 1.5 years to date. These four patients experienced a single, self-limited episode of diarrhea within 2 weeks of the infusion, and did not require subsequent CDI treatment. Two patients had recurrent symptoms and positive stool C. difficile tests one month after infusion and were re-started on CDI treatment. One of the patients had longstanding underlying irritable bowel syndrome and variable initial response to re-starting vancomycin. The other patient responded to re-starting fidaxomicin. Conclusion Bezlotoxumab at the end of a prolonged suppressive treatment regimen may be an effective therapeutic strategy in preventing recurrent CDI in complicated, multiply recurrent CDI patients. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]