Purpose: Management of complex fistulas is a challenge due to the limitations of current treatments. Expanded adipose derived mesenchymal Stem Cells (Cx401) is a novel cell therapy based on immunoregulation and cell proliferation which helps repair damaged tissue.
Methods: A multicenter, randomized, controlled trial is being conducted to evaluate the efficacy and safety of Cx401 in 49 adult patients with complex perianal fistula from Cryptoglandular (35) or Crohn (14) diseases. Patients received fibrin glue or 20 million cells plus fibrin glue intralesionally. Fistula healing was evaluated at 8 wks. If not healed, a second dose of fibrin glue or 40 million cells plus fibrin glue was administered, with healing evaluated 8 wks later. Healing was defined as absence of drainage (spontaneous or by gentle compression) and complete re-epithelization of the external openings.
Results: The proportion of patients whose fistulas were healed was significantly higher with Cx401 than with fibrin glue [17(70.83%) vs 4(16.00%) respectively, RR=4.43(CI 1.74, 11.27);p-value=0.0001]. Efficacy was observed in Crohn and non-Crohn. 45% of Cx401 patients received a cumulative dose of 60 million cells. At 6 months follow-up, 2 SAEs were observed in each group. Only one SAE was related to fibrin glue, no SAE was related to Cx401
Conclusions: A dose of 20-60 million Expanded Adipose-derived Stem Cells (Cx401) in combination with fibrin glue is an effective and safe treatment for complex perianal fistula.
Cx401 Efficacy data: Primary Endpoint (healing)

DATA - Frequency (%)	Cx401 (N=24)	Fibrin glue (N=25)	Relative Risk CI (95%) p-value (chi-square)
Healing	17 (70.83%)	4 (16.00%)	4.43 (1.74, 11.27) p-value=0.0001

Expanded Adipose-derived Mesenchymal Stem Cells (Cx401)