Approval Probability
TA Base Rate
Adjusted LOA
ML Risk
Label indication DIFICID is a macrolide antibacterial indicated in adult and pediatric patients 6 months of age and older for the treatment of C. difficile -associated diarrhea. ( 1.1 ) To reduce the development of drug-resistant bacteria and maintain the effectiveness of DIFICID and other antibacterial drugs, DIFICID should be used only to treat infections that are proven or strongly suspected to be caused by C. difficile . FDA label
Also known as Fidaxomicin oral suspension, DIFICID, DIFICLIR, OPT-80, PAR-101
fidaxomicin · 5 trials · 4 indications
Initial clinical response (ICR) for ages from birth to \< 2 years was defined as absence of watery diarrhea for 2 consecutive treatment days, remaining well until study drug discontinuation. ICR for ages ≥ 2 years to \< 18 years was defined as improvement in number and character of bowel movements as determined by \< 3 unformed bowel movements (UBMs) per day for 2 consecutive treatment days, remaining well until study drug discontinuation. CCR was defined for both age groups as not requiring further CDAD therapy within 2 days after study drug completion, and was reported with a positive (Yes) or negative (No) outcome. Resolution of diarrhea was assessed during interviews of participant/parent/legal guardian, supplemented by review of personal records (if hospitalized) and checked for presence of watery diarrhea (ages from birth to \< 2 years) or number of UBMs (for ages ≥ 2 years to \< 18 years).
CDAD is defined as follows: Diarrhea: (change in bowel habits with \>3 unformed bowel movements in a 24 hour period) and the presence of either toxin A and/or B (or their respective genes, tcdA and/or tcdB) of C. difficile in the stool determined by C. difficile toxin assay. Wald 95% Confidence Intervals (CI) are presented.
Percentage of participants with 3 or fewer unformed stools for 2 consecutive days and maintained through the end of therapy, and the subject no longer needed specific anti-Clostridium antibacterial treatment after completion of the course of study medication.
Number of participants with adverse events, as categorized by MedDRA.
3-5 hour plasma levels of fidaxomicin (mean)
End of therapy fecal levels of fidaxomicin (mean)
3-5 hour plasma levels of OP-1118 (mean)
End of therapy fecal levels of OP-1118 (mean)
| Arm | Type | Description |
|---|---|---|
| Fidaxomicin | EXPERIMENTAL | Participants from birth to \< 6 years of age received weight based doses of fidaxomicin oral suspension (32 mg/kg/day with a maximum dose of 400 mg/day divided in 2 doses) 2 times daily for 10 days. Participants aged ≥ 6 years to \< 18 years of age received a 200 mg fidaxomicin tablet 2 times daily for 10 days. |
| Vancomycin | ACTIVE_COMPARATOR | Participants from birth to \< 6 years of age received weight based doses of vancomycin oral liquid (40 mg/kg/day with a maximum dose of 500 mg/day divided in 4 doses) 4 times daily for 10 days. Participants aged ≥ 6 years to \< 18 years of age received a 125 mg vancomycin capsule 4 times daily for 10 days. |
| Placebo | PLACEBO_COMPARATOR | Placebo tablet once daily for no longer than 40 days |
| Name | Type | Description |
|---|---|---|
| Fidaxomicin oral suspension | DRUG | Participants from birth to \< 6 years of age received weight based doses of fidaxomicin oral suspension (32 mg/kg/day with a maximum dose of 400 mg/day divided in 2 doses) 2 times daily for 10 days. |
| Fidaxomicin tablets | DRUG | Participants aged ≥ 6 years to \< 18 years of age received a 200 mg fidaxomicin tablet 2 times daily for 10 days. |
| Vancomycin oral liquid | DRUG | Participants from birth to \< 6 years of age received weight based doses of vancomycin oral liquid (40 mg/kg/day with a maximum dose of 500 mg/day divided in 4 doses) 4 times daily for 10 days. |
| Vancomycin capsules | DRUG | Participants aged ≥ 6 years to \< 18 years of age received a 125 mg vancomycin capsule 4 times daily for 10 days. |
| fidaxomicin | DRUG | Fidaxomicin 200 mg tablet once daily from the start (+/- 2 days) of condition (prior to transplantation) or at the time of Fluoroquinolone initiation. Study drug treatment will continue until 7 days after either neutrophil engraftment or the completion of any Fluoroquinolone antibiotic regimen (whichever occurs later). Study drug treatment will stop at onset of CDAD or no longer than 40 days of duration, even if other antibiotics are still administered or neutrophil engraftment extends beyond 40 days. |
| Placebo | DRUG | Placebo tablet once daily from the start (+/- 2 days) of condition (prior to transplantation) or at the time of Fluoroquinolone initiation. Treatment will continue until 7 days after either neutrophil engraftment or the completion of any Fluoroquinolone antibiotic regimen (whichever occurs later). Treatment will stop at onset of CDAD or no longer than 40 days of duration, even if other antibiotics are still administered or neutrophil engraftment extends beyond 40 days. |
| Vancomycin | DRUG | 125 mg capsules q6hr (4 times a day) |
| Matching Placebo to Fidaxomicin | DRUG | Matching Placebo to Fidaxomicin administered two times daily (intermittently with fidaxomicin dosing) |
| OPT-80 | DRUG | - |
Inclusion Criteria: * Subject is diagnosed with CDAD according to local diagnostic criteria. As a minimum there must be positive detection, within 72 hours prior to randomization, of either toxin A and/or toxin B in stool or positive detection of toxigenic C. difficile in stool and: * Subject fr...
Fidaxomicin is used to treat Clostridium difficile-associated diarrhea (CDAD) and Clostridium infections. It is an oral small molecule antibacterial developed by Merck & Company, Inc. (ticker MRK). Clinical development has covered both adult and pediatric patients with CDAD, including a Phase 3 study in adults undergoing hematopoietic stem cell transplantation.
Fidaxomicin is developed by Merck & Company, Inc., which trades under the ticker MRK. Merck has sponsored the clinical trial program for the drug, including pediatric and adult studies of the oral suspension and tablet formulations in Clostridium difficile-associated diarrhea.
Fidaxomicin has been studied in Phase 3 clinical development for Clostridium difficile-associated diarrhea and Clostridium infections, with additional Phase 2 work in pediatric patients. Its registered trials are listed as completed, and no trials are currently active.
Fidaxomicin has been evaluated in completed trials including NCT02218372, a Phase 3 pediatric study of the oral suspension or tablets versus vancomycin; NCT01691248, a Phase 3 prophylaxis study in adults undergoing hematopoietic stem cell transplantation; NCT01591863, a Phase 2 pediatric pharmacokinetics study; and NCT00314951, a Phase 3 comparison with vancomycin.
Yes. Fidaxomicin oral suspension is an alternative name for fidaxomicin, referring to the liquid oral formulation of the same drug. It has been studied alongside fidaxomicin tablets, including in the Phase 3 pediatric trial NCT02218372 in Clostridium difficile-associated diarrhea.
Across the registered fidaxomicin trials, total enrollment is 797 participants. The studies were randomized, double-blind, and used active-controlled designs, with enrollment spanning pediatric patients from 6 months of age and adults, including those undergoing hematopoietic stem cell transplantation.