The Safety of Fecal Microbiota Transplantation for Crohn’s Disease: Findings from A Long-Term Study

All procedures performed in this study involving human participants were in accordance with the Second Affiliated Hospital of Nanjing Medical University Institutional Ethical Review Board and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all participants included in the study.

FMT via mid-gut for mild to severe CD with the Harvey Bradshaw Index (HBI) > 4 as a registered trial was performed from October 2012 to December 2016 at the Second Affiliated Hospital of Nanjing Medical University. This study was retrospectively registered with clinicaltrials.gov. Trial registration date: 13/2/2013. Trial registration number: NCT01793831. All patients and donors were informed of the benefits and potential risks of FMT and laboratory screening. All written informed consentd were obtained. Eligible subjects required documentation of definite diagnosis of CD.

Donors were considered to be suitable according to our screening criteria [6]. Healthy donors were selected from patients’ relatives or friends or from our universal stool bank (China fmtBank), and carefully screened using the following exclusion criteria: history of drug use (e.g., antibiotic, laxative or diet pill use within the past 3 months; prior immunomodulator or chemotherapy use) and history of disease (e.g., infectious diseases, obesity, diabetes, IBD, irritable bowel syndrome, chronic diarrhea, constipation, colorectal polyps or malignant neoplasm, immunocompromised states, metabolic syndrome, allergy, history of major gastrointestinal operation or auto-immune diseases, as well as any other diseases or conditions related to the disturbance of intestinal microbiota). All donors accepted laboratory examinations, such as regular blood tests, C-reactive proteins, erythrocyte sedimentation rates, immunoglobulin subtypes, biochemical tests, hepatitis-associated indices, HIV, syphilis, Cytomegalovirus, Epstein–Barr virus, rubella virus, herpes simplex virus, toxoplasma, and stool testing (including stool culture, stool ova and parasites).

Fecal samples were obtained from scanned donors after signing the informed consent, and were processed for enriching microbiota in the laboratory by manual methods (before April 2014) or automatic methods based on the automatic purification machine GenFMTer (FMT Medical, Nanjing, China) [7] (since April 2014). We followed the “1-h FMT protocol”, which means that the time from the stool coming out of the colon to the patient’s intestine or storing at − 80 °C refrigerator is required to be finished within 1 h [7]. The stored fecal microbiota needed be thawed at 37–39 °C before infusion into the patient’s intestine. However, after we had confirmed that the frozen FMT induced the decreased rate of clinical improvement by 26.7% at 6 months post-FMT compared with the fresh FMT in CD at our earlier phase [6], the fresh FMT has become the first and even the most important suggestion to patients with CD in our practice. The purified fecal microbiota was delivered into the mid-gut through a naso-jejunal tube or gastroscopic infusion under anesthesia.

All AEs were recorded during the follow-up after FMT. The longest follow-up time was 5 years. All AEs were described using Common Terminology Criteria for Adverse Events (CTCAE) as in our previous study [6]. Grade refers to the severity of the AE. The CTCAE displays Grades 1–5 with clinical descriptions of severity for AE based on the guideline.

The efficacy of FMT was evaluated at 1 month after FMT. The activity of disease was assessed by HBI based on abdominal symptoms, examination findings, and the presence of extraintestinal manifestations [6, 7]. Clinical response was defined as the HBI score decreasing to  > 3. Clinical remission was defined as HBI  ≤ 4 after FMT. All patients who achieved clinical remission were included in the analysis of clinical response.

Data were analyzed by using SPSS 18.0. Analyses included the nonparametric test, Chi square test, Fisher’s exact test and logistic analysis. Two-tailed P value was calculated with each test. P < 0.05 was considered significant.

A totla of 156 patients with moderate to severe CD underwent FMT from October 2012 to December 2016. Of these, 17 (10.9%) patients were excluded, as 9 had incomplete medical records, and the remaining 8 patients were lost to follow-up. Finally, 139 patients were included for the analyses (Table 1).

In total, 139, 106 and 32 patients were included for analysis with 12 months, 2 years and 5 years of follow-up, respectively. All FMTs were delivered through the mid-gut. A total of 33 patients underwent multiple FMTs for maintaining clinical response during a long-term period. The second FMT for CD was performed generally 3–6 months after the first FMT [7]. Six patients were performed the second FMT within 1–3 months after the first FMT in consideration of their serious condition. In total, 184 FMTs were performed for 139 patients. Of these, 13.6% (25/184) of AEs occurred within 1 week after FMT (Fig. 1). Only herpes zoster was observed within 1 week after FMT but it was cured within 1 month. According to CTCAE, the relevance to FMT was classified as probable or possible, and 84.0% (21/25) of AE were considered grade 1. All AEs occurred after FMT and 84% of them were self-improvement without medication treatment (Table 2). Only four patients (16%) with AEs were treated with medication. One (4%) had persistent fever after FMT and was prescribed oral prednisone in consideration that the FMT might fail to induce clinical improvement. Hematochezia occurred in one patient after FMT; however, the symptom disappeared after the repeated FMT. One patient required to be discharged due to increased frequency of defecation after FMT. This patient gradually recovered from corticosteroid treatment in another hospital. There were no serious AEs after FMT during the follow-up.

A total of 139 patients at the first FMT were included for further analysis of the possible risk factors for AEs of FMT. Logistic analysis adjusting for the confounders showed that only manual fecal microbiota purification methods were an independent risk factor for FMT-related AEs (OR = 3.644, 95% CI 1.414–9.393, P = 0.007). A total of 21.7% (15/69) patients had AEs after FMT in the group of manual methods was lower than the 8.7% (10/115) in the group of automatic preparations (Table 3).

We further analyzed the efficacy of FMT and its relevance with the methods of fecal microbiota purification and the occurrence of AEs (Table 4). No significant difference was observed between the group with manual methods and the group with automatic methods, indicating that the method of fecal microbiota preparation should not affect the efficacy of FMT for active CD. Interestingly, the rate of clinical response and clinical remission were 45% (9/20) and 20% (4/20) in the patients with AE, which was significantly lower than 75.6% (90/119) and 63.0% (75/119) in the group without AE, respectively.