ClostridiumPhase 4OpTIONNCT02667418
Optimal Treatment for Recurrent Clostridium Difficile
A Phase 4 study testing Fidaxomicin, Vancomycin with Taper/Pulse and Vancomycin in people with Clostridium and Difficile, run by VA Office of Research and Development at 33 sites in 2 countries.
Trial summary
The purpose of this study is to determine whether fidaxomicin and vancomycin followed by taper and pulse vancomycin treatment are superior to standard vancomycin treatment for the treatment of recurrent Clostridium difficile infection. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Clostridium, Difficile, Fidaxomicin
- What is being tested?
- Fidaxomicin, Vancomycin with Taper/Pulse and Vancomycin
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 308 participants
- Where
- 33 sitesin 2 countries
- Study dates
- 19 Feb 2016to 31 Aug 2024
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Informed consent obtained and signed
- Age > 18
- If female, participant must not be pregnant or nursing
- Negative pregnancy test required for females <61 years of age or without prior hysterectomy
- Confirmed current diagnosis of CDI, determined by having
- >3 loose or semi-formed stools for participants over 24 hours AND
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- Positive stool assay for C. difficile
- EIA positive for toxin A/B; or
- Cytotoxin assay; or
- Nucleic Acid Amplification Test (NAAT, PCR or LAMP) based detection of toxigenic C. difficile
- Current episode represents the first recurrent episode of CDI within 3 months of the primary CDI episode in a patient who has not had CDI in the 3 months prior to the primary episode OR a second recurrent CDI episode occurring within 3 months of the first recurrent episode, as defined above
- At least one of the previous CDI episodes must have been confirmed by a stool assay for C. difficile
Who cannot join
- Inability to provide informed consent
- Inability to take oral capsules
- Receipt of >72 hours of antibiotics considered effective in the treatment of CDI, including:
- metronidazole
- vancomycin
- fidaxomicin
Show all 15Show fewer
- nitazoxanide
- rifaximin
- Prior infusion of bezlotoxumab within the previous 6 months
- Known presence of fulminant CDI, including hypotension, severe ileus or GI obstruction or incipient toxic megacolon
- Receipt of more than a single course of oral vancomycin, fidaxomicin, or a vancomycin tapering regimen since the primary episode of CDI as defined above
- Known allergy to vancomycin or fidaxomicin
- Acute or chronic diarrhea due to inflammatory bowel disease or other cause (e.g., presence of an ileostomy or colostomy) that would confound evaluation of response to CDI treatment
- Anticipation of need for long term systemic antibiotic treatment (beyond 7 days)
- Patients with an active diagnosis of COVID-19 will be excluded from the study, but patients who have recovered (per current CDC guidance on discontinuation of transmission-based precautions) can be included in the study.
Trial locations and contacts
33 sites in 2 countries.
33 sites in 2 countries
United States32 sites
VA Ann Arbor Healthcare System, Ann Arbor, MI
Ann Arbor, Michigan, 48105
Asheville VA Medical Center, Asheville, NC
Asheville, North Carolina, 28805-2576
Rocky Mountain Regional VA Medical Center, Aurora, CO
Aurora, Colorado, 80045-7211
Rehabilitation R&D Service, Baltimore, MD
Baltimore, Maryland, 21202
Bay Pines VA Healthcare System, Pay Pines, FL
Bay Pines, Florida, 33744-0000
VA Boston Healthcare System Jamaica Plain Campus, Jamaica Plain, MA
Boston, Massachusetts, 02130-4817
Jesse Brown VA Medical Center, Chicago, IL
Chicago, Illinois, 60612
Louis Stokes VA Medical Center, Cleveland, OH
Cleveland, Ohio, 44106-1702
VA North Texas Health Care System Dallas VA Medical Center, Dallas, TX
Dallas, Texas, 75216-7167
Atlanta VA Medical and Rehab Center, Decatur, GA
Decatur, Georgia, 30033-4004
John D. Dingell VA Medical Center, Detroit, MI
Detroit, Michigan, 48201-1916
Durham VA Medical Center, Durham, NC
Durham, North Carolina, 27705-3875
North Florida/South Georgia Veterans Health System, Gainesville, FL
Gainesville, Florida, 32608-1135
Edward Hines Jr. VA Hospital, Hines, IL
Hines, Illinois, 60141-3030
Edward Hines Jr. VA Hospital, Hines, IL
Hines, Illinois, 60141
Michael E. DeBakey VA Medical Center, Houston, TX
Houston, Texas, 77030
Central Arkansas Veterans Healthcare System, Little Rock, AR
Little Rock, Arkansas, 72205
VA Loma Linda Healthcare System, Loma Linda, CA
Loma Linda, California, 92357
VA Long Beach Healthcare System, Long Beach, CA
Long Beach, California, 90822
Clement J. Zablocki VA Medical Center, Milwaukee, WI
Milwaukee, Wisconsin, 53295-0001
Oklahoma City VA Medical Center, Oklahoma City, OK
Oklahoma City, Oklahoma, 73104-5007
VA Palo Alto Health Care System, Palo Alto, CA
Palo Alto, California, 94304-1290
Phoenix VA Health Care System, Phoenix, AZ
Phoenix, Arizona, 85012
VA Portland Health Care System, Portland, OR
Portland, Oregon, 97207-2964
VA Northern California Health Care System, Mather, CA
Sacramento, California, 95655-4200
VA Salt Lake City Health Care System, Salt Lake City, UT
Salt Lake City, Utah, 84148
South Texas Health Care System, San Antonio, TX
San Antonio, Texas, 78229
VA San Diego Healthcare System, San Diego, CA
San Diego, California, 92161
VA Puget Sound Health Care System Seattle Division, Seattle, WA
Seattle, Washington, 98108
James A. Haley Veterans' Hospital, Tampa, FL
Tampa, Florida, 33612
Southern Arizona VA Health Care System, Tucson, AZ
Tucson, Arizona, 85723-0001
VA Greater Los Angeles Healthcare System, West Los Angeles, CA
West Los Angeles, California, 90073
Puerto Rico1 site
VA Caribbean Healthcare System, San Juan, PR
San Juan, 00921
About this study
Official title: CSP #596 - Optimal Treatment for Recurrent Clostridium Difficile Infection
The purpose of this study is to determine whether fidaxomicin and vancomycin followed by taper and pulse vancomycin treatment are superior to standard vancomycin treatment for the treatment of recurrent Clostridium difficile infection.
Read the detailed description
Abstract Clostridium difficile is the most common cause of healthcare-associated infectious diarrhea among adults in industrialized countries. In addition to diarrhea, C. difficile infection (CDI) may also result in serious complications such as shock, toxic megacolon, colectomy, and death. The Centers for Disease Control and Prevention (CDC) has estimated C. difficile results in 250,000 hospital infections, 14,000 deaths, and $1 billion in excess costs annually. Recurrent CDI is the most challenging clinical dilemma facing clinicians who treat this disease. An estimated 30% of patients who respond to initial treatment with either vancomycin or metronidazole develop recurrent CDI, usually within 1-4 weeks of completing treatment.
The primary objective of this study is to determine whether 1) standard fidaxomicin treatment and 2) standard vancomycin treatment followed by taper and pulse vancomycin treatment are superior to standard vancomycin treatment alone for sustained clinical response at day 59 for all treatments, for participants with either their first or second recurrence of CDI. Veterans presenting with a first or second CDI recurrence will be screened, consented and randomly assigned in a double-blind manner equally to one of three treatment groups: 1) a 10 day course of oral vancomycin (VAN-TX), 2) a 10 day course of fidaxomicin (FID-TX) or 3) a 31 day course of vancomycin which includes a taper and pulse following daily treatment (VAN-TP/P). Symptom resolution is defined as an improvement or resolution of diarrhea ( 3 unformed bowel movements over 24 hours) for 48 consecutive hours compared to the participant's baseline. Recurrence is defined as having diarrhea (>3 loose or semi-formed stools over 24 hours for 48 consecutive hours). A sample size of 459 randomized study participants is required to obtain 91% global power to detect a 16% absolute difference (expected proportion of 31% in the VAN-TX group) in sustained clinical response (D- COM) proportion for at least one comparison (VAN-TP/P vs. VAN-TX, FID-TX vs. VAN-TX) at the family wised error rate (FWER) 0.05 level. The marginal probability (disjunctive power) of detecting 16% absolute difference for each comparison is 81%. The expected withdrawal rate prior to day 59 (prior outcome assessment) is estimated to be 10%. If both FID-TX and VAN-TP/P are found to be superior to VAN-TX, then the non-inferiority of VAN-TP/P to FID-TX will be assessed.
With the assumption that sites recruit 4 participants (site average) per year for sites primarily recruiting from the main hospital and nearby CBOCS, and 6 participants (site average) per year for sites that could partner with independent VAMCs (Independent VAMCs LSI Application will be reviewed and approved by Central IRB) that are close in distance to allow a shared site coordinator (WOC appointed) at an increased funding level, the study is expected to complete enrollment of 459 participants within 6 years with 90 days of follow-up. This includes 2 years of pilot phase plus transitioning period from pilot phase to full study, and 4 years of full study. There were 6 sites in the pilot phase and will have 24 units (26 sites) in full phase (including 5 pilot sites and 21 additional sites). Sites that are significantly below the recruitment target for an extensive period may be considered for termination. The recruitment timeline and the number of sites will be re-evaluated based on the actual recruitment rate, the number of sites still recruiting, whether replacement or additional sites will be added, the study time period on administrative recruitment hold due to COVID-19 pandemic, and available funding resources.
- Conditions
- Clostridium, Difficile, Fidaxomicin, Vancomycin
- Being tested
- Fidaxomicin, Vancomycin with Taper/Pulse, Vancomycin
- Keywords
- Clostridium, Difficile, Fidaxomicin, Vancomycin, Recurrent, Pulse, Taper
- Medical subject headings
- Recurrence
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FidaxomicinDrug
200 mg PO twice daily for 10 days
Vancomycin with Taper/PulseDrug
125 mg PO four times daily for 10 days, followed by 125 mg once daily x 7 days, then once every other day x 7 days, then once every 3rd day x 7 days
VancomycinDrug
125 mg PO for times daily for 10 days
| Study group | Role | What they receive |
|---|---|---|
| Fidaxomicin | Other | Standard 10-day fidaxomicin treatment for Clostridium difficile Receives: Drug: Fidaxomicin |
| Vancomycin T/P | Other | Standard 10-day vancomycin treatment followed by taper and pulse vancomycin treatment for Clostridium difficile Receives: Drug: Vancomycin with Taper/Pulse |
| Vancomycin | Other | Standard 10-day vancomycin treatment for Clostridium difficile Receives: Drug: Vancomycin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Sustained Clinical Response as Measured at Study Day 59 for All Treatment Regimens
The Primary outcome will be sustained clinical response as measured at study day 59 for all treatment regimens. Sustained clinical response is a composite outcome that includes symptom resolution during treatment without any of the following (as assessed on day 59):
- Diarrhea recurrence
- Other non-fatal clinical events including severe abdominal pain, toxic megacolon (where diarrhea ceases but is not a beneficial outcome), and colectomy
- Death
Measured: Day 59 for all treatment regimens.
Secondary outcomes (14)
Sustained Diarrhea Composite Outcome (D-COM) at 28 Days Post End of Therapy
Sustained Diarrhea Composite Outcome (D-COM) at 28 days Post End of Therapy- Secondary Analyses of Primary Outcome. Sustained clinical response without recurrent CDI (CDI-COM) at 28 days post end of therapy for all three treatment regimens. Sustained clinical response was defined using the same criteria as previously stated except that the endpoint will be 28 days after the last dose of treatment drug for each treatment arm (day 38 for vancomycin and fidaxomicin, and day 59 for vancomycin taper/pulse).Sustained clinical response is a composite endpoint defined as symptom resolution during treatment without diarrhea recurrence, mortality or other important clinical outcomes at any time during the follow-up period. Those participants failing to meet the criteria of symptom resolution (diarrhea resolution) by the end of the active treatment (day 10 for all groups), or who experience a recurrence during the follow-up period, will be considered study treatment failures.
Measured: 28 Days Post End of Therapy
Clostridium Difficile Infection Composite Outcome (CDI-COM)
Clostridium difficile Infection Composite Outcome (CDI-COM) at day 59 post randomization. Sustained response in CDI-COM is defined using the same composite endpoint criteria as was used in the D-COM composite outcome but with confirmation of no CDI recurrence by a negative C. difficile stool assay test (i.e., proportion of subjects who achieve symptom resolution by day 10 without recurrent CDI, without non-fatal clinical events, and without death).
Measured: Day 59 post randomization
Symptom Resolution
The percentage of participants who had symptom resolution by Day 10 post randomization
Measured: Day 10 since randomization
CDI Recurrence
CDI recurrence following initial symptom resolution
Measured: Day 90 since randomization
Diarrhea Recurrence
Diarrhea recurrence with confirmation of recurrent CDI following initial symptom resolution
Measured: Day 90 since randomization
C.Diff Health Related Quality of Life (HRQOL)
Change in patient reported C.diff Health Related Quality of Life (HRQOL) from baseline (day 0) to day 10. The HRQOL is measured with patient self-reported 32-item questionnaire. The summary measure, CDiff32-QOL, is the total score that sums over 32 individual items with each item rated on a 5-point Likert scale and then transformed to a 100-point scale with higher score indicating better C.diff Health Related QOL in general. The full scale of the HRQOL: 1-5 on a 5-point Likert scale and 0-100 on the 100-point scale; the minimum: 0 on the 100-point scale and maximum value: 100 on the 100-point scale. The summary measure (32 items) range on the 100-point scale: 0-3200.
Measured: Day 10 since randomization
C.Diff Health Related Quality of Life (HRQOL)
Change in patient reported C.diff Health Related Quality of Life (HRQOL) from baseline day 0 to day 59. The HRQOL is measured with patient self-reported 32-item questionnaire. The summary measure, CDiff32-QOL, is the total score that sums over 32 individual items with each item rated on a 5-point Likert scale and then transformed to a 100-point scale with higher score indicating better C.diff Health Related QOL in general. The full scale of the HRQOL: 1-5 on a 5-point Likert scale and 0-100 on the 100-point scale; the minimum: 0 on the 100-point scale and maximum value: 100 on the 100-point scale. The summary measure (32 items) range on the 100-point scale: 0-3200.
Measured: day 0- day 59
Sustained Clinical Response (D-COM) BI/NAP1/027 Strain as "Yes"
Sustained clinical response (D-COM) at day 59 for subgroups (infection with the BI/NAP1/027 strain (yes) at study enrollment; etc.). The sliced analysis was used to break down the subgroup factors into different sub-levels and then to explore the differences between treatment group (VAN-TP and FDX) and VAN control group at each level.
Measured: Day 59 since randomization
Diarrhea Recurrence
Diarrhea recurrence with confirmation of recurrent CDI following initial symptom resolution. Diarrhea recurrence and diarrhea recurrence with confirmation of recurrent CDI following initial symptom resolution. Diarrhea (>3 loose or semi-formed stools over 24 hours) over 48 consecutive hours in participants who achieved initial symptom resolution will be recorded separately from sustained clinical response as will confirmed CDI recurrence.
Measured: Day 38 since randomization
Diarrhea Recurrence
Diarrhea recurrence with confirmation of recurrent CDI following initial symptom resolution
Measured: Day 59 since randomization
CDI Recurrence
CDI recurrence following initial symptom resolution
Measured: Day 38 since randomization
CDI Recurrence
CDI recurrence following initial symptom resolution
Measured: Day 59 since randomization
Sustained Clinical Response (D-COM) With the BI/NAP1/027 Strain no
Sustained clinical response (D-COM) at day 59 for subgroups (infection with the BI/NAP1/027 strain (no) at study enrollment; etc.). The sliced analysis was used to break down the subgroup factors into different sub-levels and then to explore the differences between therapy group (VAN-TP and FDX) and VAN control group at each level.
Measured: Day 59 since randomization
Sustained Diarrhea Composite Outcome (D-COM) at 90 Days After Randomization
Sustained Diarrhea Composite Outcome (D-COM) at 90 days after Randomization - Secondary Analyses of Primary Outcome
Measured: 90 Days After Randomization
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jan 2016 (estimated)
- Study start19 Feb 2016
- Primary completion7 Aug 2024
- Study completion31 Aug 2024
Why it stopped: The study sponsor stopped the trial early after enrolling 308 of the target sample size because of a slower than expected recruitment rate.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for ClostridiumStudies of the same condition, open and under way.
- More trials run by VA Office of Research and DevelopmentThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 308 participants (actual)
Sponsor and investigators
- Lead sponsor
- VA Office of Research and Development
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
- Investigators
- Stuart B. Johnson, MD BA, Study chair, Edward Hines Jr. VA Hospital, Hines, ILDale N Gerding, MD, Study chair, Edward Hines Jr. VA Hospital, Hines, IL
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02667418
- Sponsor's protocol ID
- 596
- Other IDs
- #15-03, 1613088
- Acronym
- OpTION
- Status last verified
- Jul 2026
- First submitted
- 25 Jan 2016
- Last updated
- 21 Aug 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Johnson S, Gerding DN, Li X, Reda DJ, Donskey CJ, Gupta K, Goetz MB, Climo MW, Gordin FM, Ringer R, Johnson N, Johnson M, Calais LA, Goldberg AM, Ge L, Haegerich T. Defining optimal treatment for recurrent Clostridioides difficile infection (OpTION study): A randomized, double-blind comparison of three antibiotic regimens for patients with a first or second recurrence. Contemp Clin Trials. 2022 May;116:106756. doi: 10.1016/j.cct.2022.106756. Epub 2022 Apr 7.
PubMed 35398532Johnson S, Gerding DN, Donskey CJ, et al. Vancomycin Taper and Pulse or Fidaxomicin for Recurrent C. difficile Infection. NEJM Evidence 2026;5(8): EVIDoa2600016. DOI: 10.1056/EVIDoa2600016
Study at a glance
From the registry record, last updated by the sponsor on 21 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- CSP #596 - Optimal Treatment for Recurrent Clostridium Difficile Infection
- ClinicalTrials.gov ID
- NCT02667418
- Acronym / sponsor ID
- OpTION / 596
- Conditions
- Clostridium, Difficile, Fidaxomicin, Vancomycin
- Keywords
- Clostridium, Difficile, Fidaxomicin, Vancomycin, Recurrent, Pulse, Taper
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: The study sponsor stopped the trial early after enrolling 308 of the target sample size because of a slower than expected recruitment rate.
- Enrolment
- 308 participants (actual)
- Lead sponsor
- VA Office of Research and DevelopmentUS federal agency
- Study start
- 19 Feb 2016 (actual)
- Primary completion
- 7 Aug 2024 (actual)
- Study completion
- 31 Aug 2024 (actual)
- First posted
- 28 Jan 2016 (estimated)
- Results
- Posted 12 Nov 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine whether fidaxomicin and vancomycin followed by taper and pulse vancomycin treatment are superior to standard vancomycin treatment for the treatment of recurrent Clostridium difficile infection.
Detailed description
Abstract Clostridium difficile is the most common cause of healthcare-associated infectious diarrhea among adults in industrialized countries. In addition to diarrhea, C. difficile infection (CDI) may also result in serious complications such as shock, toxic megacolon, colectomy, and death. The Centers for Disease Control and Prevention (CDC) has estimated C. difficile results in 250,000 hospital infections, 14,000 deaths, and $1 billion in excess costs annually. Recurrent CDI is the most challenging clinical dilemma facing clinicians who treat this disease. An estimated 30% of patients who respond to initial treatment with either vancomycin or metronidazole develop recurrent CDI, usually within 1-4 weeks of completing treatment.
The primary objective of this study is to determine whether 1) standard fidaxomicin treatment and 2) standard vancomycin treatment followed by taper and pulse vancomycin treatment are superior to standard vancomycin treatment alone for sustained clinical response at day 59 for all treatments, for participants with either their first or second recurrence of CDI. Veterans presenting with a first or second CDI recurrence will be screened, consented and randomly assigned in a double-blind manner equally to one of three treatment groups: 1) a 10 day course of oral vancomycin (VAN-TX), 2) a 10 day course of fidaxomicin (FID-TX) or 3) a 31 day course of vancomycin which includes a taper and pulse following daily treatment (VAN-TP/P). Symptom resolution is defined as an improvement or resolution of diarrhea ( 3 unformed bowel movements over 24 hours) for 48 consecutive hours compared to the participant's baseline. Recurrence is defined as having diarrhea (>3 loose or semi-formed stools over 24 hours for 48 consecutive hours). A sample size of 459 randomized study participants is required to obtain 91% global power to detect a 16% absolute difference (expected proportion of 31% in the VAN-TX group) in sustained clinical response (D- COM) proportion for at least one comparison (VAN-TP/P vs. VAN-TX, FID-TX vs. VAN-TX) at the family wised error rate (FWER) 0.05 level. The marginal probability (disjunctive power) of detecting 16% absolute difference for each comparison is 81%. The expected withdrawal rate prior to day 59 (prior outcome assessment) is estimated to be 10%. If both FID-TX and VAN-TP/P are found to be superior to VAN-TX, then the non-inferiority of VAN-TP/P to FID-TX will be assessed.
With the assumption that sites recruit 4 participants (site average) per year for sites primarily recruiting from the main hospital and nearby CBOCS, and 6 participants (site average) per year for sites that could partner with independent VAMCs (Independent VAMCs LSI Application will be reviewed and approved by Central IRB) that are close in distance to allow a shared site coordinator (WOC appointed) at an increased funding level, the study is expected to complete enrollment of 459 participants within 6 years with 90 days of follow-up. This includes 2 years of pilot phase plus transitioning period from pilot phase to full study, and 4 years of full study. There were 6 sites in the pilot phase and will have 24 units (26 sites) in full phase (including 5 pilot sites and 21 additional sites). Sites that are significantly below the recruitment target for an extensive period may be considered for termination. The recruitment timeline and the number of sites will be re-evaluated based on the actual recruitment rate, the number of sites still recruiting, whether replacement or additional sites will be added, the study time period on administrative recruitment hold due to COVID-19 pandemic, and available funding resources.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Fidaxomicin | Other | Drug: FidaxomicinStandard 10-day fidaxomicin treatment for Clostridium difficile |
| Vancomycin T/P | Other | Drug: Vancomycin with Taper/PulseStandard 10-day vancomycin treatment followed by taper and pulse vancomycin treatment for Clostridium difficile |
| Vancomycin | Other | Drug: VancomycinStandard 10-day vancomycin treatment for Clostridium difficile |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (12 listed)
- Informed consent obtained and signed
- Age > 18
- If female, participant must not be pregnant or nursing
- Confirmed current diagnosis of CDI, determined by having
- Current episode represents the first recurrent episode of CDI within 3 months of the primary CDI episode in a patient who has not had CDI in the 3 months prior to the primary episode OR a second recurrent CDI episode occurring within 3 months of the first recurrent episode, as defined above
Key exclusion criteria (15 listed)
- Inability to provide informed consent
- Inability to take oral capsules
- Receipt of >72 hours of antibiotics considered effective in the treatment of CDI, including:
- Prior infusion of bezlotoxumab within the previous 6 months
- Known presence of fulminant CDI, including hypotension, severe ileus or GI obstruction or incipient toxic megacolon
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fidaxomicin200 mg PO twice daily for 10 days | Drug | Fidaxomicin |
| Vancomycin with Taper/Pulse125 mg PO four times daily for 10 days, followed by 125 mg once daily x 7 days, then once every other day x 7 days, then once every 3rd day x 7 days | Drug | Vancomycin T/P |
| Vancomycin125 mg PO for times daily for 10 days | Drug | Vancomycin |
Primary outcome
Number of Participants With Sustained Clinical Response as Measured at Study Day 59 for All Treatment Regimens
Time frame: Day 59 for all treatment regimens.
The Primary outcome will be sustained clinical response as measured at study day 59 for all treatment regimens. Sustained clinical response is a composite outcome that includes symptom resolution during treatment without any of the following (as assessed on day 59): 1. Diarrhea recurrence 2. Other non-fatal clinical events including severe abdominal pain, toxic megacolon (where diarrhea ceases but is not a beneficial outcome), and colectomy 3. Death
14 secondary outcomes
Sustained Diarrhea Composite Outcome (D-COM) at 28 Days Post End of Therapy
Time frame: 28 Days Post End of Therapy
Clostridium Difficile Infection Composite Outcome (CDI-COM)
Time frame: Day 59 post randomization
Symptom Resolution
Time frame: Day 10 since randomization
CDI Recurrence
Time frame: Day 90 since randomization
Diarrhea Recurrence
Time frame: Day 90 since randomization
C.Diff Health Related Quality of Life (HRQOL)
Time frame: Day 10 since randomization
C.Diff Health Related Quality of Life (HRQOL)
Time frame: day 0- day 59
Sustained Clinical Response (D-COM) BI/NAP1/027 Strain as "Yes"
Time frame: Day 59 since randomization
Diarrhea Recurrence
Time frame: Day 38 since randomization
Diarrhea Recurrence
Time frame: Day 59 since randomization
CDI Recurrence
Time frame: Day 38 since randomization
CDI Recurrence
Time frame: Day 59 since randomization
Sustained Clinical Response (D-COM) With the BI/NAP1/027 Strain no
Time frame: Day 59 since randomization
Sustained Diarrhea Composite Outcome (D-COM) at 90 Days After Randomization
Time frame: 90 Days After Randomization
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Aug 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 35398532Johnson S, Gerding DN, Li X, Reda DJ, Donskey CJ, Gupta K, Goetz MB, Climo MW, Gordin FM, Ringer R, Johnson N, Johnson M, Calais LA, Goldberg AM, Ge L, Haegerich T. Defining optimal treatment for recurrent Clostridioides difficile infection (OpTION study): A randomized, double-blind comparison of three antibiotic regimens for patients with a first or second recurrence. Contemp Clin Trials. 2022 May;116:106756. doi: 10.1016/j.cct.2022.106756. Epub 2022 Apr 7.
- Results publicationJohnson S, Gerding DN, Donskey CJ, et al. Vancomycin Taper and Pulse or Fidaxomicin for Recurrent C. difficile Infection. NEJM Evidence 2026;5(8): EVIDoa2600016. DOI: 10.1056/EVIDoa2600016
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Stuart B. Johnson, MD BA study chair
Edward Hines Jr. VA Hospital, Hines, IL
Dale N Gerding, MD study chair
Edward Hines Jr. VA Hospital, Hines, IL
33 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Fidaxomicin, Vancomycin with Taper/Pulse and Vancomycin in people with Clostridium and Difficile, run by VA Office of Research and Development at 33 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 12 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 21 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 33 sites in United States, Puerto Rico. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 12 Nov 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Sustained Clinical Response as Measured at Study Day 59 for All Treatment Regimens (time frame: Day 59 for all treatment regimens.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02667418, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Aug 2026.