Fidaxomicin-Associated Hypersensitivity Reactions: Report of a Morbilliform Drug Eruption.

PurposeWe report a probable case of morbilliform drug eruption secondary to fidaxomicin in a patient with Clostridioides difficile infection (CDI). Summary: A 62-year-old female presented to our institution's emergency department (ED) with symptoms consistent with Clostridioides difficile infection. The patient was prescribed 2 weeks of oral vancomycin for CDI prior to presentation. Given insufficient response to vancomycin, the patient was started on fidaxomicin with a planned 10-day course. After 2 doses of fidaxomicin, the patient developed a rash on her back that spread within 24 hours. The patient did not experience relief upon administration of a variety of medications for allergic reaction. Improvement was noted upon discontinuation of fidaxomicin. The Food and Drug Administration reports that < 2% of adults treated with fidaxomicin experience a rash as an adverse effect. Conclusion: Fidaxomicin was a probable cause of morbilliform drug eruption in our patient with CDI. The patient improved upon discontinuation of fidaxomicin.

Fecal Microbiota Transplantation Is Superior to Fidaxomicin for Treatment of Recurrent Clostridium difficile Infection.

BACKGROUND & AIMS: Fecal microbiota transplantation (FMT) is recommended for treatment of recurrent Clostridium difficile infection (rCDI). We performed a single-center randomized trial to compare the effects of FMT with those of fidaxomicin and vancomycin. METHODS: We studied consecutive adults with rCDI seen at a gastroenterology clinic in Denmark from April 5, 2016 through June 10, 2018. Patients were randomly assigned to a group that received FMT, applied by colonoscopy or nasojejunal tube, after 4-10 days of vancomycin (125 mg 4 times daily; FMTv; n = 24), 10 days of fidaxomicin (200 mg twice daily; n = 24), or 10 days of vancomycin (125 mg 4 times daily; n = 16). Patients who had rCDI after this course of treatment and patients who could not be randomly assigned to groups were offered rescue FMTv. The primary outcome was combined clinical resolution and a negative result from a polymerase chain reaction test for Clostridium difficile (CD) toxin 8 weeks after the allocated treatment. Secondary end points included clinical resolution at week 8. RESULTS: All 64 patients received their assigned treatment. The combination of clinical resolution and negative results from the test for CD were observed in 17 patients given FMTv (71%), 8 patients given fidaxomicin (33%), and 3 patients given vancomycin (19%; P = .009 for FMTv vs fidaxomicin; P = .001 for FMTv vs vancomycin; P = .31 for fidaxomicin vs vancomycin). Clinical resolution was observed in 22 patients given FMTv (92%), 10 patients given fidaxomicin (42%), and 3 patients given vancomycin (19%; P = .0002; P < .0001; P = .13). Results did not differ significantly between patients who received FMTv as their initial therapy and patients who received rescue FMTv. There was 1 serious adverse event that might have been related to FMTv. CONCLUSIONS: In a randomized trial of patients with rCDI, we found the FMTv combination superior to fidaxomicin or vancomycin based on end points of clinical and microbiological resolution or clinical resolution alone. ClinicalTrials.gov, number NCT02743234; EudraCT, j.no 2015-003004-24.

Pharmacokinetics and safety of fidaxomicin in patients with inflammatory bowel disease and Clostridium difficile infection: an open-label Phase IIIb/IV study (PROFILE).

Objectives: Inflammatory bowel disease (IBD) poses an increased risk for Clostridium difficile infection (CDI). Fidaxomicin has demonstrated non-inferiority to vancomycin for initial clinical cure of CDI in patients without IBD; however, lack of data has caused concerns regarding potential systemic absorption of fidaxomicin in patients with IBD. Methods: The plasma pharmacokinetics (PK) of fidaxomicin and its primary metabolite OP-1118 were evaluated in a multicentre, open-label, single-arm, Phase IIIb/IV study enrolling patients with active IBD and CDI. Patients received fidaxomicin, 200 mg twice daily for 10 days. The primary and secondary endpoints were, respectively, plasma and stool PK of fidaxomicin and OP-1118 on Days 1, 5 and 10 of treatment. Other secondary endpoints included safety of fidaxomicin treatment (assessed until Day 180). ClinicalTrials.gov identifier: NCT02437591. Results: Median Tmax of fidaxomicin and OP-1118 for the PK analysis set (PKAS; 24 patients) was 1-2 h across Days 1, 5 and 10. Cmax ranges were 1.2-154 ng/mL for fidaxomicin and 4.7-555 ng/mL for OP-1118 across Days 1, 5 and 10 (PKAS). The ranges of concentrations in stool were 17.8-2170 µg/g for fidaxomicin and 0-1940 µg/g for OP-1118. Sixty percent (15/25) of patients experienced treatment-emergent adverse events (TEAEs), none of which led to treatment discontinuation or death. Conclusions: Maximum fidaxomicin and OP-1118 plasma concentrations observed in this study population suggest no increase in absorption, compared with patients without IBD. Incidence of TEAEs was similar to previous Phase III trials, suggesting that fidaxomicin is comparatively well tolerated in patients with IBD.

Fidaxomicin for the treatment of Clostridium difficile infection (CDI) in at-risk patients with inflammatory bowel disease, fulminant CDI, renal impairment or hepatic impairment: a retrospective study of routine clinical use (ANEMONE).

Information is limited or lacking on fidaxomicin treatment of Clostridium difficile infection (CDI) in patients with inflammatory bowel disease, fulminant or life-threatening CDI, severe renal impairment, moderate-to-severe hepatic impairment and pregnancy. The ANEMONE study investigated fidaxomicin use in a routine clinical setting, focusing on these medical conditions of specific interest (MCSIs). This retrospective, post-authorisation study reviewed hospital records from Austria, Germany, Spain and the UK (June 2012-June 2015), collecting data from hospital admission to 30 days after last fidaxomicin dose. The primary objective was to identify the proportion of fidaxomicin-treated patients with MCSIs. Secondary objectives were to describe 30-day mortality, changes in ECG and laboratory parameters, fidaxomicin exposure and CDI response (resolution of diarrhoea; 30-day recurrence). 45.3% (261/576) of patients had ≥ 1 MCSI. Thirty-day mortality (post-first dose) was 17.0% (98/576) in the total population and slightly higher (24.6-27.6%) in patients with fulminant CDI or severe renal impairment. 29.6% (24/81) deaths of known cause were attributable to CDI. Of changes in laboratory parameters or ECG findings, only a decrease in leucocyte counts appeared associated with fidaxomicin, consistent with a positive treatment response. Diarrhoea resolved in 78.0% (404/518) of treatment episodes; diarrhoea resolution was lowest in patients with fulminant CDI (investigator-defined, 67.5%, 56/88) and severe renal impairment (68.0%, 68/100). Thirty-day recurrence (18.8%, 79/420) was similar across MCSI subgroups. Although almost half of fidaxomicin-treated patients had ≥ 1 MCSI, the majority of patients in all subgroups had positive responses to treatment, and no particular safety concerns were identified.

Retrospective evaluation of fidaxomicin versus oral vancomycin for treatment of Clostridium difficile infections in allogeneic stem cell transplant.

OBJECTIVE/BACKGROUND: Clostridium difficile infection (CDI) is a potential complication during hematopoietic stem cell transplantation (HSCT), and no specific recommendations exist regarding treatment of CDI in allogeneic SCT patients. Use of metronidazole and oral vancomycin has been associated with clinical failure. Fidaxomicin has previously been found noninferior to the use of oral vancomycin for the treatment of CDI, and no studies have compared the use of oral vancomycin with fidaxomicin for the treatment of CDI in allogeneic SCT. METHODS: This retrospective chart review included 96 allogeneic SCT recipients who developed CDI within 100 days following transplantation. Participants were treated with oral vancomycin (n = 52) or fidaxomicin (n = 44). The primary outcome was clinical cure, defined as no need for further retreatment 2 days following completion of initial CDI treatment. Secondary outcomes were global cure, treatment failure, and recurrent disease. RESULTS: No differences in clinical cure were observed between patients receiving oral vancomycin or fidaxomicin (75% vs. 75%, p = 1.00). Secondary outcomes were similar between oral vancomycin and fidaxomicin in regards to global cure (66% vs. 67%, p = .508), treatment failure (28% vs. 27%, p = .571), and recurrent disease (7% vs. 5%, p = .747). In a subanalysis of individuals that developed acute graft-versus-host disease following CDI, the difference in mean onset of acute graft-versus-host disease was 21.03 days in the oral vancomycin group versus 32.88 days in the fidaxomicin group (p = .0031). CONCLUSION: The findings of this study suggest that oral vancomycin and fidaxomicin are comparable options for CDI treatment in allogeneic SCT patients within 100 days following transplant.

Probable fidaxomicin-induced pancytopenia.

PURPOSE: A case of pancytopenia in a patient receiving treatment with fidaxomicin for Clostridium difficile infection (CDI) is described. SUMMARY: A 33-year-old Caucasian woman was admitted to the hospital with a chief complaint of loose stools occurring approximately 7 times a day; she also reported fever, nausea, diffuse abdominal pain, and fatigue. The patient had a history of recurrent CDI, recurrent urinary tract infections, nephrolithiasis, chronic hepatitis C, and endometriosis. Her previous therapies for CDI included metronidazole, vancomycin, rifaximin, and fecal microbiota transplantation. On admission, she had a platelet count of 172,000 platelets/mm3, hemoglobin concentration of 11.1 g/dL, and white blood cell (WBC) count of 3,100 cells/mm3. Within 24 hours of the first dose of fidaxomicin and before the second dose, the patient's platelet count fell to 156,000 platelets/mm3, her hemoglobin concentration decreased to 9.9 g/dL, and her WBC count fell to 2,600 cells/mm3. Values for all 3 tests continued to decrease during the first few days of fidaxomicin therapy. One dose of filgrastim 300 µg was administered subcutaneously on day 6 in response to the pancytopenia, after which the platelet, hemoglobin, and WBC values stabilized for a day and then generally declined. Platelet, hemoglobin, and WBC values returned to normal within 3 days of the patient's last dose of fidaxomicin. Use of the Naranjo et al. adverse drug reaction probability scale indicated a probable association (score of 6) between fidaxomicin and the patient's pancytopenia. CONCLUSION: A 33-year-old woman developed pancytopenia during a course of fidaxomicin therapy for CDI. Platelet, hemoglobin, and WBC values returned to normal within 3 days of the final fidaxomicin dose.