Wright, Emily Kate

Abstract Background Darvadstrocel (DVS), a suspension of expanded allogeneic adipose-derived mesenchymal stem cells, is approved for the treatment of complex Crohn’s perianal fistulas (CPF). INSPIRE (EUPAS24267) is a European observational post-approval study evaluating real-world effectiveness and safety of DVS in patients with complex CPF for up to 36 months. Here we report preliminary clinical and safety outcomes from INSPIRE. Methods Patients with complex CPF who had received DVS according to local standard practice were eligible to enrol. Clinical response (closure of ≥50% of external openings [EOs]) and clinical remission (closure of all EOs) of DVS-treated fistulas that were draining at baseline, were evaluated in the all-treated (AT; received ≥1 dose of DVS with an evaluation for fistula response after 6 months) and per-protocol (PP; received DVS as per label-approved guidelines) cohorts. Treatment-emergent adverse events (TEAEs), serious TEAEs and AEs of special interest were reported for the safety cohort (all patients treated with DVS). Results As of April 2023, 652 patients had enrolled (Table 1). Complete data to evaluate 12-month clinical response and remission were available for 134 (AT cohort) and 124 (PP cohort) patients, of whom 79.9% (AT, n = 107) and 79.8% (PP, n = 99) had a clinical response and 76.1% (AT, n = 102) and 76.6% (PP, n = 95) had clinical remission (Figure 1). From baseline to Month 12, there was a decrease in the mean (standard deviation [SD]) Perianal Disease Activity Index score (–3.5 [3.3]; n/N = 96/302 and –3.7 [3.2]; n/N = 89/249) and a decrease in the mean (SD) Harvey–Bradshaw Index for Crohn’s disease activity (-0.3 [2.8]; n/N = 102/302 and -0.4 [2.9]; n/N = 95/249) in the AT and PP cohorts, respectively. Complete safety data were available for 619 patients (median [min–max] follow-up 480 [6–1595]) days. Overall, 26% (n = 162) had ≥1 TEAE and 10% (n = 63) ≥1 serious TEAE. The most frequent TEAEs were anal abscess (6.9%), COVID-19 (1.9%) and proctalgia (1.1%). No deaths were reported. One breast cancer lymph node metastasis and one ovarian epithelial cancer were reported; both events were confounded by immunosuppressant treatment and were not considered related to DVS treatment. Conclusion These preliminary data are consistent with the pivotal ADMIRE-CD study and demonstrate a single dose of DVS in patients with complex CPF is associated with positive clinical outcomes in up to 80% of patients, and a favourable safety profile, both of which are maintained after 12 months. The inherent limitations of registry-based studies mean these data should be interpreted with caution. However, the ongoing INSPIRE study will provide longer follow-up data to confirm these observations with respect to any study limitations.

Abstract Background Complex perianal fistulas are a serious complication in patients with Crohn’s disease (CD). Darvadstrocel (DVS), a suspension of expanded adult allogeneic adipose-derived mesenchymal stem cells, is approved in Europe and Japan for treatment of complex Crohn’s perianal fistulas (CPF). The global ADMIRE-CD II phase 3 randomized double-blind placebo-controlled study evaluated the efficacy and safety of DVS for treatment of complex CPF. Methods Patients aged 18–75 years with clinically controlled, inactive or mildly active CD and complex CPF (≤2 internal openings [IO] and ≤3 external openings [EOs]) who had an inadequate, or a loss of response to immunosuppressive agents or biologics were included. Patients were randomized 1:1 to receive a local injection of DVS as a single dose (120 x 106 cells/24 mL) or placebo. In all patients, fistula preconditioning included vigorous curettage and seton placement 2–3 weeks before treatment, and seton removal, a further curettage and closure of IOs immediately before treatment. The primary endpoint was combined remission (closure of all treated EOs that were draining at baseline, despite gentle finger compression, and absence of collections >2 cm confirmed by MRI) at 24 weeks. Secondary endpoints included combined remission at 52 weeks, clinical remission (closure of all treated EOs without MRI confirmation) at 24 and 52 weeks, and time to clinical remission at 24 weeks. Safety was monitored up to 52 weeks. Results From 19 Oct 2017 to 26 Jul 2023, 568 patients received DVS (n = 283) or placebo (n = 285) with fistula preconditioning; 56.3% of patients enrolled in Europe and Israel, and 43.7% in North America. Mean (SD) age, sex and race were similar in the DVS and placebo arms (38.4 [11.9] vs 37.7 [10.8] years; 42.8% vs 45.6% female; 85.9% vs 89.1% White). Combined remission rates at 24 weeks did not statistically differ between treatments (48.8% DVS vs 46.3% placebo) and there were no differences in secondary endpoints (Table 1; Figure 1). Based on health authority guidelines, post hoc analyses of patients randomized before COVID-19 (11 March 2020; n = 141 DVS, n = 143 placebo) were performed: combined remission rates at 24 weeks were 46.8% (DVS) and 38.5% (placebo). The safety profile for DVS was consistent with prior studies with no new safety signals (Table 1). Conclusion The efficacy outcomes assessed did not statistically differ between DVS and placebo, and the placebo response rate (with fistula preconditioning) was higher than expected. Post hoc analyses revealed lower placebo response rates in patients randomized before COVID-19 (similar to the pivotal ADMIRE CD I study) than the overall placebo arm. DVS was well tolerated.