Comparative Efficacy of Mesalazine and Ozanimod following Induction Treatment in Mesalazine-Exposed Advanced Therapy-Naïve Adult Ulcerative Colitis Patients.

Geert D’Haens and Ekaterina Safroneeva should be considered joint
first authors.

Introduction
Both mesalazine and ozanimod are oral treatment options for patients with moderately active ulcerative colitis (UC).Methods
Comparative analysis comparing efficacy endpoints of an 8-week non-inferiority induction study (TP0503) with 3.2 g/day mesalazine (n = 321) to the True North 10-week induction study of 1 mg/day ozanimod (n = 281). We compared the efficacy of oral mesalazine (Asacol) as monotherapy and ozanimod (Zeposia) as add-on therapy to mesalazine, without concomitant corticosteroids, following induction treatment in mesalazine-exposed but immunomodulator- and advanced therapy-naïve UC patients. Endpoints from the non-inferiority study were re-calculated using the definitions from the True North study.Results
The two cohorts had similar age (45 ± 14 years vs. 44 ± 13.5 years) and baseline disease severity (total Mayo score; 8.5 ± 0.8 vs. 8.6 ± 1.1) for mesalazine- and ozanimod-treated patients, respectively. No differences were observed in patients achieving clinical response (reduction from baseline in the 3-component Mayo score [sum of rectal bleeding subscore/RBS, stool frequency subscore/SFS, and Mayo endoscopic score/MES) of ≥2 points and ≥35%, and a reduction from baseline in the RBS of ≥1 point or an absolute RBS ≤1} (58% vs. 58%; p = 0.917) and clinical remission (RBS = 0, SFS ≤1 [and decreases of ≥1 point from baseline SFS], and MES ≤1) (22% vs. 28%; p = 0.074) treated with mesalazine (at 8 weeks) and ozanimod (at 10 weeks), respectively. A higher percentage of patients treated with ozanimod achieved endoscopic improvement (MES ≤1 without friability) compared to mesalazine (38% vs. 29%, p = 0.018).Conclusion
Among individuals previously exposed to mesalazine, a similar effect on clinical efficacy was observed between patients treated with mesalazine and those treated with ozanimod.