31 7.5 – Limitations and Challenges of Using FMT
Study Limitations
There were several limitations that affected the study. It was a single center pilot study conducted without any control groups (He et al. 2017). Control groups are essential when conducting any study, because it allows the comparison of how efficient or inefficient a treatment is. There was also no endoscopic assessment for each patient, so the internal digestive tract was not observed (He et al. 2017). The metabolic and microbial analyses for comprehending the mechanism of the microbiota were not conducted (He et al. 2017).
Biological Limitations
Variable results based on biological differences occurs frequently across different labs as well as during a single lab. The different donors would have different microbiota compositions based on geographic locations, diet, and lifestyle habits. Different patient conditions such as the locations of the abscesses or phlegmons, or the use of antibiotics prior to FMT could affect the efficiency of FMT treatments and the remission rates for each patient (He et al. 2017).
Another biological limitation involves the inefficiency of frozen fecal samples for FMT (He et al. 2017). Although fresh and frozen fecal samples are similar in efficacy when treating for recurrent C.difficile infections (CDI), it is not the same for Crohn’s Disease (CD) (He et al. 2017). A previous pilot study using frozen fecal microbiota samples was conducted, and they concluded that the patients who used frozen fecal microbiota samples had lower clinical responses at 3 months after the FMT compared fresh fecal microbiota samples (He et al. 2017).
Timing of Treatments
After the first FMT induced remission, it remained unclear when to exactly give repeated FMTs to the patients (He et al. 2017). Based on the study’s observations, the repeated FMTs given to maintain the previous FMT’s efficacy should be between 3-6 months, but it was recommended to be given every 3 months (He et al. 2017). Some patients who were satisfied with the outcomes after the first FMT induced remission refused additional FMTs (He et al. 2017). It was also inconvenient for some patients to travel to the hospital for repeated FMTs (He et al. 2017). These factors might have contributed to the decreased rate of clinical improvement and clinical remission at 18 months after the first FMT (He et al. 2017).