AVB-114 Demonstrates Clinical Benefit in Persistent Crohn's Perianal Fistulas: Randomized Cohort Results from the Multicenter STOMP2 Trial.

INTRODUCTION:Advanced therapies infrequently achieve complete fistula closure in patients with Crohn's disease (CD). The primary objective of the STOMP2 clinical trial was to determine whether the implantable autologous cell therapy AVB-114 is effective in inducing remission of persistent Crohn's perianal fistulas versus standard of care. METHODS:Eligible patients had a single perianal fistula tract and had failed previous treatment or had documented medication intolerance to biologic or conventional CD therapy. All enrolled subjects underwent surgical fistula optimization and adipose tissue biopsy collection (to manufacture AVB-114) followed by 1:1 randomization to either standard of care (repeat fistula optimization including seton replacement) or AVB-114 implantation. The primary end point was combined fistula remission at 36 weeks, defined as closure of the external opening, no drainage of fluid despite gentle finger compression, and no collections >2 cm in at least 2 of the 3 dimensions on MRI. RESULTS:Subjects at 14 US sites were equally randomized to SoC (N = 24) or AVB-114 (N = 24). Week 36 combined remission was 8.3% and 45.8% for subjects randomized to SoC and AVB-114, respectively (38% difference, 95% CI 11%-60%; P = 0.0078). At week 36, MRI revealed no subjects with collections >2 cm, radiological improvement (≥50% decrease in the Magnetic Resonance Novel Index for Fistula Imaging in Crohn's Disease (MAGNIFI-CD) score from baseline) in 1 SoC subject and 3 AVB-114 subjects, and radiological healing (complete resolution of T2-weighted hyperintensity in fistula tract) in 2 SoC subjects and 5 AVB-114 subjects. Through week 36, there were 40 and 56 treatment emergent adverse events for SoC and AVB-114, respectively. There were no serious treatment emergent adverse events in the AVB-114 group through week 36. DISCUSSION:A significantly higher proportion of patients treated with AVB-114 achieved combined remission vs SoC, and the treatment was well tolerated. These data support the safety and efficacy of AVB-114 in persistent Crohn's perianal fistulas.