Oral Vancomycin Followed by Fecal Transplantation Versus Tapering Oral Vancomycin Treatment for Recurrent Clostridium difficile Infection: An Open-Label, Randomized Controlled Trial
Fecal Transplant vs Vancomycin Taper • CID
Oral Vancomycin Followed by Fecal Transplantation Versus Tapering Oral Vancomycin Treatment for Recurrent Clostridium difficile Infection: An Open-Label, Randomized Controlled Trial
Susy S. Hota () 0 4 5 10
Valerie Sales 0 3 4 10
George Tomlinson 0 9 10
Mary Jane Salpeter 0 5 8
Allison McGeer 0 4 7 12
Bryan Coburn 0 4 10 11
David S. Guttman 0 2 6
Donald E. Low 0 1 4 7 12
Susan M. Poutanen 0 4 7 12
0 Received 18 May 2016; editorial decision 8 September 2016; accepted 31 October 2016; published online November 9, 2016
1 D. E. L. passed away and is posthumously included as an author in recognition of his signif- icant contribution to this study. 103, Toronto General Hospital , 200 Elizabeth St, Toronto, ON M5G 2C4 , Canada
2 Centre for the Analysis of Genome Evolution and Function, University of Toronto , Toronto , Canada
3 Department of Medicine, Markham-Stouffville Hospital , Markham
4 Department of Medicine, University of Toronto
5 Department of Infection Prevention and Control, University Health Network , Toronto
6 Department of Cell and Systems Biology, University of Toronto
7 Department of Microbiology, University Health Network/Sinai Health System
8 Department of Anaesthesia, University Health Network
9 Institute of Health Policy, Management and Evaluation and Dalla Lana School of Public Health, University of Toronto
10 Department of Medicine, University Health Network
11 Toronto General Research Institute, University Health Network
12 Department of Laboratory Medicine and Pathobiology, University of Toronto
(See the Editorial Commentary by Johnson and Gerding on pages 272-4.) Background. Fecal transplantation (FT) is a promising treatment for recurrent Clostridium difficile infection (CDI), but its true effectiveness remains unknown. We compared 14 days of oral vancomycin followed by a single FT by enema with oral vancomycin taper (standard of care) in adult patients experiencing acute recurrence of CDI. Methods. In a phase 2/3, single-center, open-label trial, participants from Ontario, Canada, experiencing recurrence of CDI were randomly assigned in a 1:1 ratio to 14 days of oral vancomycin treatment followed by a single 500-mL FT by enema, or a 6-week taper of oral vancomycin. Patients with significant immunocompromise, history of fulminant CDI, or irreversible bleeding disorders were excluded. The primary endpoint was CDI recurrence within 120 days. Microbiota analysis was performed on fecal filtrate from donors and stool samples from FT recipients, as available. Results. The study was terminated at the interim analysis after randomizing 30 patients. Nine of 16 (56.2%) patients who received FT and 5 of 12 (41.7%) in the vancomycin taper group experienced recurrence of CDI, corresponding with symptom resolution in 43.8% and 58.3%, respectively. Fecal microbiota analysis of 3 successful FT recipients demonstrated increased diversity. A futility analysis did not support continuing the study. Adverse events were similar in both groups and uncommon. Conclusions. In patients experiencing an acute episode of recurrent CDI, a single FT by enema was not significantly different from oral vancomycin taper in reducing recurrent CDI. Further research is needed to explore optimal donor selection, FT preparation, route, timing, and number of administrations. Clinical Trials Registration. NCT01226992.
regimen of oral vancomycin over 6–8 weeks [3, 4]. However, as
an antibiotic, vancomycin may perpetuate the problem by further
interfering with the intestinal microbiota. Moreover, the
effectiveness of tapering vancomycin is poorly understood.
Fecal transplantation (FT), the introduction of feces from
a healthy donor into the intestinal tract of someone with
disrupted microbiota, is a promising salvage therapy for RCDI.
Multiple systematic reviews of largely uncontrolled,
heterogeneous studies, have reported success rates of 80%–93%
for RCDI [5–9]. Five randomized trials have shown
symptom resolution in 70%–94%; however, none of these studies
compared FT to standard of care treatment and not all
evaluated FT for treatment of active episodes of RCDI [10–14].
Therefore, the true effectiveness of FT, as compared to current
standard of care, for treatment of an acute episode of RCDI
remains uncertain. Furthermore, FTs are being manufactured
and performed with considerable variability and some of these
factors may affect outcome . Consequently, best practice
guidelines, specialist groups, and regulatory bodies have both
endorsed and cautioned clinicians about FT [3, 4, 16–20].
With the hypothesis that FT was superior to oral
vancomycin taper, we conducted a randomized controlled trial (RCT)
comparing the effectiveness of 14 days of oral vancomycin
followed by a single FT by enema with standard of care treatment,
a 6-week taper of oral vancomycin, in patients experiencing an
acute episode of RCDI.
Design and Participants
We conducted a phase 2/3, single-site, open-label RCT
comparing 14 days of oral vancomycin followed by a single fecal
transplant (FT) by enema with 6 weeks of oral vancomycin taper in
adult patients experiencing an acute episode of RCDI. FT was
performed using fresh donations from screened, healthy donors
identified by the recipients. Research ethics board and Health
Canada approvals were obtained. A data and safety monitoring
committee monitored the trial.
Participants were recruited in Ontario, Canada. Consenting
adult (≥18 years of age) patients were included if they had a
history of at least 2 episodes of laboratory or pathology-confirmed
CDI, and had received at least one course of oral vancomycin
(minimum 10 days of 500 mg total daily dose). Symptoms of
CDI were self-reported and confirmed by study physicians
to meet standard epidemiologic definitions of diarrhea .
Enzymatic immunoassay (EIA) for C. difficile toxin or
polymerase chain reaction (PCR) for C. difficile toxin gene was accepted
for laboratory confirmation.
Exclusions included neutropenia, graft-vs-host disease,
or other severe immunocompromised states; CDI requiring
intensive care unit admission; evidence of active, severe colitis
unresponsive to oral vancomycin; hypersensitivity or
intolerance to oral vancomycin; chronic gastrointestinal diseases
that may cause diarrhea; planned therapy in the next 120 days
that may cause diarrhea (eg, chemotherapy); planned surgery
requiring perioperative antibiotics within 120 days;
pregnancy; significant bleeding disorder; or inability to tolerate FT
Consenting adult (≥18 years age) potential donors were
screened using a self-screening questionnaire of behaviors
associated with risk for blood-borne pathogens, study
physician assessment, and blood and stool testing for potentially
transmissible infections. Donor screening occurred after
randomization of a participant to FT and within 2 weeks of
FT. Donor exclusion criteria (see Supplementary Methods 1)
and screening were developed in consultation with Health
Upon recurrence of CDI, participants were randomized at a 1:1
ratio to either intervention. Investigators and participants were
not blinded to interventions as it would be impractical due to
FT odor, and sham enemas were not endorsed by the research
ethics board due to unnecessary potential risk.
For vancomycin taper, participants received 14 days of
vancomycin 125 mg orally every 6 hours followed by a taper over
4 weeks: vancomycin 125 mg orally every 12 hours for 1 week;
then, vancomycin 125 mg orally every 24 hours for 1 week;
then, vancomycin 125 mg orally every second day for 1 week;
then, vancomycin 125 mg orally every third day for 1 week.
Patients randomized to FT received 14 days of oral
vancomycin 125 mg every 6 hours followed by one FT by enema, 48
hours after stopping vancomycin. Donors provided stool from
their most recent bowel movement, no more than 48 hours
before FT. Fifty grams of donated feces was homogenized with
500 mL of normal saline in a Stomacher Lab Blender using
a sterile 330-µm microfilter-separated double compartment
polyethylene bag. Five hundred milliliters of fecal filtrate was
transferred to an enema bag and delivered immediately to the
patient over 10–30 minutes. These proportions were selected
based on published methodologies for FT at the time of study
design [22–24]. The manufacturing of FT was validated for
viability of aerobes and anaerobes using semiquantitative
Participants were followed for 120 days. For vancomycin
taper, day 0 was the first day of the 4-week taper whereas for
FT, day 0 was the day of FT. Participants reported by telephone
and submitted stools for testing if diarrhea occurred between
days 0 and 120. Stools were also requested for microbiota
analysis at baseline, day 7, and day 120. Two study visits (at
days 7 and 120) and 4 telephone visits (at days 4, 21, 42, and
84) evaluated possible CDI recurrence and adverse events.
Participants who experienced RCDI were offered crossover to
the alternative study treatment and followed for an additional
The primary outcome was recurrence of symptomatic,
laboratory-confirmed CDI within 120 days of the intervention,
using criteria outlined in the inclusion criteria. Safety
outcomes included solicited adverse events at days 4 and 7;
unsolicited adverse events within 14 days of interventions; serious
adverse events throughout follow-up; mortality attributable to
CDI during follow-up; and all-cause mortality throughout
follow-up. Other secondary outcomes included recurrence of CDI
symptoms within 14 and 120 days (not laboratory-confirmed);
recurrence of CDI within 120 days of crossover; days of
diarrhea in the 120 days of follow-up; and CDI requiring hospital
admission. Standardized questionnaires were used to assess for
symptoms of RCDI and adverse events.
Fecal Microbiota Analysis
Fecal microbiota analysis was performed retrospectively on
frozen fecal filtrate from 19 donors and stool from 3 recipients
with successful outcomes (baseline; 7 days post-FT; 16 weeks
post-FT, as available). DNA was extracted using PowerSoil
DNA Isolation Kit (Mo Bio Laboratories, Carlsbad, California).
The V4 hypervariable region of the 16S rRNA locus was
interrogated using the V4-515F and V4-806R primers  and
analyzed with QIIME . Diversity indices were compared using
Student t test (Supplementary Methods 2).
Using a 2-sided test for comparison of 2 independent
proportions, and assuming 8% recurrence in the FT group , 30%
recurrence in the vancomycin arm , 80% power, and α of
.05, we required 57 participants per intervention (114
participants total). Assuming 20% attrition over follow-up, 138
participants were required for randomization.
We planned an interim analysis for safety and feasibility after
the completion of the first 30 participants. The trial was stopped
at the interim analysis and a futility analysis based on the
primary outcome was added using a Bayesian approach . The
primary analysis was per protocol and secondary analysis was
intention to treat. For the primary outcome, we calculated the
posterior distribution of the risk difference and the
probability that the absolute risk reduction exceeded several clinically
important thresholds (any reduction, >10%, and >20%). All
Bayesian analyses used uniform priors on proportions. Analyses
of safety and secondary outcomes were descriptive. All analyses
were done using R 3.2.1 .
Between January 2011 and July 2014, 140 patients were assessed
for eligibility (Figure 1). Forty were ineligible on prescreening
and 19 declined participation, primarily due to unwillingness
to be randomized. Of the 81 consented patients, 3 met
exclusion criteria and 48 (59.2%) did not experience recurrence of
symptomatic, laboratory-confirmed CDI over the study period,
which was required for randomization. Of these 48 patients, 2
experienced diarrhea not meeting case definition and 6
experienced self-limited diarrhea meeting case definition but with
negative C. difficile laboratory tests. Thirty patients were
randomized: 14 to vancomycin taper and 16 to FT. Two patients
in the vancomycin taper group withdrew—one to seek FT
elsewhere and another due to repeated protocol noncompliance.
Thus, 12 patients in the vancomycin taper arm and 16 in the FT
arm were included in the interim analysis.
Baseline characteristics were similar in both
randomization groups (Table 1). Most randomized patients were women
and had a history of 4–5 episodes (range, 2–9) of CDI prior to
entering the trial. Thirteen (13/16) of the FT and 10 of 12 of the
vancomycin taper patients had failed at least one vancomycin
taper prior to enrollment. In comparison to those randomized,
patients who were not randomized because they did not have an
episode of RCDI were younger, had fewer recurrences, and had
lower mean Charlson comorbidity scores. In the FT group, 10
of 16 participants retained at least 80% (400 cc) of the enema.
Of 18 donors screened, 2 were excluded on the basis of stool
and blood testing. Most donors were male (12/16) with a mean
age of 50 years. Eleven (11/16) were blood relatives of the
recipient and 4 (4/16) lived within the same household as the
recipient at the time of donation.
Nine of 16 (56.2%) patients who received FT and 5 of 12
(41.7%) in the vancomycin taper group experienced recurrence,
corresponding with resolution of symptoms in 43.8% and
58.3%, respectively (Figure 2). Recurrence occurred a median
of 9 days after FT treatment and 35 days after initiating
vancomycin tapering (7 days after completing the vancomycin taper).
There was no association between donor relatedness or shared
household and FT recipient recurrence. Four of the 5 patients
who failed vancomycin taper crossed over to FT. All 4
experienced recurrence of symptoms after FT. All patients who failed
FT subsequently withdrew.
Figure 3 shows the per-protocol absolute risk reduction
estimates for CDI recurrence with FT. Although the initial plan
was for intention-to-treat analysis, given the small number of
participants, the 2 patients in the vancomycin group who did
not complete the trial were excluded. The Bayesian 95% interval
for the change in risk of CDI recurrence with FT ranged from a
2.8% reduction to a 47.3% increase. There was a posterior
probability of 22.2% that the FT reduced recurrences at all and only
a 2.8% probability that risk was reduced by 20% or more.
The futility analysis found that if the planned total of 57
patients were randomized to each treatment group, given the
current data, there was only a 3.4% probability of finding a
significant benefit for FT, defined as the upper end of the
onesided Bayesian 95% interval for the risk reduction lying below
0. Results of the futility analysis did not change using intention
In the early period (days 0–7), abdominal pain, tenderness,
and bloating were equally prevalent in the FT and vancomycin
groups (Table 2). In the later period (after 7 days), abdominal
pain, tenderness, bloating, mucoid stools, and smelly stools
were reported more frequently in the vancomycin group.
Four serious adverse events were reported in 3 patients. None
was deemed related to the study interventions. One patient in
the vancomycin taper group was hospitalized with fever and
a urinary tract infection. One FT patient was hospitalized
with anasarca and was diagnosed with end-stage liver disease.
Another FT patient experienced a perforated bowel secondary
to diverticulitis 35 days after FT. This patient had a longstanding
history of diverticulitis; upon review with the most responsible
physicians, it was decided that the FT was unlikely to be related
to the perforation.
No study participant experienced recurrence of CDI
symptoms without laboratory confirmation within 14 days or
120 days of treatment. Patients who underwent FT experienced
Nonrandomizedb (n = 48)
Any previous vancomycin taper
No. of previous vancomycin tapers
No. of previous hospital admissions for CDI
Charlson comorbidity index score
Other antibiotic use within 3 mo of
Proton pump inhibitor usee
Figure 2. Cumulative incidence of Clostridium difficile infection recurrence by
treatment group over 120 days. Day 0 indicates day of fecal transplant for fecal
transplant group and first day of tapering protocol for vancomycin taper group.
Although follow-up continued for 120 days, the y-axis ends at 60 days as there
were no recurrences beyond this timepoint.
a mean of 0.8 (SD, 0.8) days of diarrhea in follow-up,
compared with 1.7 (SD, .4) days in the vancomycin taper group. No
patients developed CDI requiring hospital admission or died.
Fecal microbiota composition and diversity of 19 FT donors
were consistently high, with no significant difference between
Figure 3. Per-protocol analysis of absolute risk reduction of Clostridium difficile
infection recurrence with fecal transplantation. Abbreviation: P (ARR), probability of
absolute risk reduction.
Table 2. Early and Late Adverse Events in Patients Randomized to Fecal
Transplantation and Vancomycin Tapera
Early Events FT (n = 16) 1 (6.2) 4 (25.0)
Abbreviations: FT, fecal transplantation; VT, vancomycin taper.
a Expressed as No. of reported events with percentage in brackets; early events were
from days 0–7 and late events were days 7–14.
b Five of the 16 patients originally randomized to FT recurred within 7 days of intervention
and therefore are not included in the measurement of late adverse events.
those associated with FT success and FT failure (Supplementary
Figure). In 3 successful FT recipients, we demonstrated
increased fecal microbiota diversity post-FT.
In this trial evaluating treatment of an acute episode of RCDI,
a single FT using fresh donor stools administered by enema
after 14 days oral vancomycin therapy had comparable
effectiveness to 6 weeks of tapered oral vancomycin, with resolution
of CDI in 43.8% and 58.3% in each group, respectively. Our trial
was stopped after randomization of 30 patients, on the basis of
FT has been widely reported as 80%–93% effective at curing
RCDI [5–14]. These high success rates are derived from studies
with various limitations. Most FT studies reporting
effectiveness >90% are observational and methodologically
heterogeneous. One RCT was stopped early, reporting 81% resolution
after a single FT by nasojejunal administration, compared with
31% after 2 weeks of oral vancomycin . Two weeks of oral
vancomycin is associated with a higher failure rate than
vancomycin taper , possibly contributing to the trial’s early
termination. A second RCT of FT by colonoscopy stopped early for
effectiveness, but it too used a comparator that was not
standard of care . A small randomized trial of FT by nasogastric
route vs colonoscopy using a frozen inoculum reported overall
CDI resolution in 90% of 20 treated patients . In another
randomized trial, clinical resolution occurred in 70.3% and
75% of patients randomized to fresh and frozen FT by enema,
respectively (n = 219) . These latter 2 studies included RCDI
patients on suppressive antibiotic therapy rather than those
experiencing acute recurrence. Without a control arm in either
trial, it is not known what proportion of patients would have
been symptom-free had their antibiotics been simply
discontinued. A multicenter, double-blind randomized trial found 90.9%
clinical cure in acute and chronic RCDI patients receiving
donor FT compared with 62.5% in those receiving autologous
FT by colonoscopy . However, at one site, 90% of patients
receiving autologous FT reported clinical cure, highlighting the
high proportion of patients labeled as RCDI who may become
symptom-free upon discontinuation of vancomycin suppressive
In the aforementioned studies, multiple administrations of
FT were often required to achieve resolution of CDI symptoms
[5, 6, 10, 13]. Single administration of FT resulted in lower
resolution of CDI: 62%, 65%, and 70% in 3 randomized trials [11–
13]. The 43.8% resolution of RCDI from a single FT observed in
our study is therefore in line with previous reports.
The timing of FT, patient pretreatment, patient and donor
selection, FT manufacturing, route of administration, and
duration of follow-up also likely have an impact on outcomes
of FT . We randomized patients once they experienced an
acute recurrence of CDI and not during symptom-free
intervals, thereby ensuring we compared patients at the same point
in their disease course. Our patients were typical for those in
whom FT would be considered in most jurisdictions. We based
our protocols for donor feces collection, delivery, and
manufacturing on published literature and an internal laboratory
validation study. We demonstrated increased microbiota diversity
post-FT in 3 recipients. Enema route was chosen for delivery
as it was supported by data, practical, inexpensive, and
well-accepted by patients . Although FT may also be administered
by colonoscopy or nasojejunal tube, to date, there are no
definitive data demonstrating superiority of one route of
administration over another [5–9, 12]. Finally, we included a long
follow-up of 120 days to capture treatment failures.
We pretreated FT patients with 14 days of oral vancomycin,
which may have negatively impacted the intestinal microbiota
such that a single FT was not sufficient for flora reconstitution.
Vancomycin was discontinued 48 hours prior to FT. Subsequent
data demonstrate that vancomycin remains detectable in feces
for 4–5 days after discontinuation of therapy, potentially
impacting the microbiota of the FT .
The ideal approach to donor selection has yet to be defined.
We did not attempt to match our donors to recipients in any
way. We demonstrated high microbiota diversity in our donor
pool, regardless of recipient relatedness, shared household, or
We present valuable data on the effectiveness of a 6-week
oral vancomycin taper, the current standard of care treatment
for multiple recurrences of CDI. Vancomycin taper resulted in
recurrence in 41.7% of our patients. This proportion is higher
than the 0–30% recurrence rate reported in 2 older
observational studies upon which current treatment recommendations
are based [28, 32].
We noted that 59% of enrolled patients never experienced
recurrence of disease and were therefore not randomized,
despite prior histories of several CDI recurrences. Seventeen
percent (8/48) of these patients experienced symptoms
suggestive of postinfectious irritable bowel disease such as
self-limited loose stools. As clinical features of RCDI in FT studies are
often self-reported and may not be corroborated by medical
assessment or laboratory confirmation, it is possible that
postinfectious irritable bowel syndrome is confounding the true
estimates of recurrence in some studies. Indeed, others have
reported similar observations [14, 33].
A limitation of our study is the small number of randomized
patients. Furthermore, our patients received FT as outpatients,
so these results cannot be extrapolated to the more acutely ill.
Finally, we were unable to perform a blinded study.
We show a similar recurrence rate in RCDI patients treated
with 14 days of oral vancomycin followed by single FT by
enema compared with oral vancomycin taper. These data
should be taken into consideration in CDI treatment
guidelines and in the design of FT programs. More research is
needed to optimize FT methodologies—specifically, donor
selection, FT manufacturing, timing, route, and number of
Acknowledgments. We thank Michael Gardam, MD, MSc, for his
Author contributions. S. S. H was the principal investigator for the trial.
She designed the RCT, carried out the research as primary clinical study
physician, oversaw conduct of the research, wrote the manuscript, and submitted
it for publication. V. S., A. M., D. E. L., and S. M. P. contributed to the study
design and interpretation of results. V. S. and S. M. P. assisted with patient
recruitment and evaluations. S. M. P. also oversaw the laboratory aspects of
FT manufacturing. G. T. performed the statistical analysis and assisted with
interpretation of results. M J. S. assisted with patient assessments, collected
study data, and coordinated the study. B. C. and D. G. performed
intestinal microbiota sequencing and analysis and participated in interpretation
of results in the context of clinical findings. All authors (excepting D. E. L.)
contributed to manuscript preparation and approved the final draft. D. E.
L. is recognized posthumously for his contribution to this research.
Financial support. This work was supported by the Physicians Services
Incorporated Foundation (grant number PSI 10-2021); Public Health Ontario;
University of Toronto Department of Medicine Integrating Challenge Grant;
University Health Network; and Sinai Health System (in kind).
Potential conflicts of interest. S. S. H. has received a grant and
honoraria from serving as a consultant and on the advisory board of Cubist
(Merck) Pharmaceuticals. A. M. has received honoraria for advisory board
participation for Cubist (Merck), and has received research funding from
GlaxoSmithKline and Merck. S. M. P. has received honoraria for
advisory board participation for Cubist (Merck), Paladin Labs, and Accelerate
Diagnostics, and has received speaker honoraria from Merck. All other
authors report no potential conflicts. All authors have submitted the ICMJE
Form for Disclosure of Potential Conflicts of Interest. Conflicts that the
editors consider relevant to the content of the manuscript have been disclosed.
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