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

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.