Stem cell therapy is linked to sustained clinical remission of fistulizing Crohn's disease, according to a new study. Therefore continued evaluation of the long-term safety and efficacy of stem cell therapy for fistulizing Crohn's disease is indicated.

The study has been published in the Inflammatory Bowel Diseases.
The efficacy of a single administration of darvadstrocel (expanded allogeneic adipose-derived mesenchymal stem cells) for treating complex perianal fistulas in patients with Crohn's disease was demonstrated in a randomized, double-blind trial (ADMIRE-CD [Adipose Derived Mesenchymal Stem Cells for Induction of Remission in Perianal Fistulizing Crohn-'s Disease] trial). The current chart review study (INSPECT [A retrospectIve chart review study evaluatINg the longer-term effectiveneSs of darvadstrocel in PatiEnts who CompleTed ADMIRE-CD]) evaluated the longer-term effectiveness and safety of darvadstrocel. Eligible patients had completed at least 52 weeks in the ADMIRE-CD trial. Data on clinical remission and fistula relapse outcomes were collected retrospectively at 104 and 156 weeks after treatment. Adverse events of special interest (tumorigenicity and ectopic tissue formation) were collected up to 208 weeks after treatment.

Results of the study are:
Eighty-nine patients were included (43 darvadstrocel patients, 46 control subjects).
At 52, 104, and 156 weeks posttreatment, clinical remission was observed in 29 (67.4%) of 43, 23 (53.5%) of 43, and 23 (53.5%) of 43 darvadstrocel-treated patients, compared with 24 (52.2%) of 46, 20 (43.5%) of 46, and 21 (45.7%) of 46 control subjects, respectively.
In patients with clinical remission at week 52, this remission was sustained at 104 and 156 weeks after treatment in 19 (65.5%) of 29 and 16 (55.2%) of 29 darvadstrocel-treated patients and in 17 (70.8%) of 24 and 13 (54.2%) of 24 control subjects, respectively.
Time to fistula relapse and incidence of fistula relapse or new fistula occurrence were not significantly different between groups.
Tumorigenicity was reported for 1 (2.2%) patient in the control group (malignant epidermoid carcinoma). No ectopic tissue formation was reported.
Thus, real-world follow-up of patients from the ADMIRE-CD trial indicates that clinical remission of complex perianal fistulas can be sustained in the long term irrespective of whether it is achieved through darvadstrocel administration or maintenance treatment regimens and confirms a favourable long-term safety profile of darvadstrocel.
Reference:
INSPECT: A Retrospective Study to Evaluate Long-term Effectiveness and Safety of Darvadstrocel in Patients With Perianal Fistulizing Crohn's Disease Treated in the ADMIRE-CD Trial by Julian Panés, et al. published in the Inflammatory Bowel Diseases.
https://doi.org/10.1093/ibd/izab361