A long-term extension study depicted that in adults with moderate-to-severe active ulcerative colitis patients, 2 mg etrasimod has a favorable safety profile. Most individuals with endoscopic improvement, clinical response, and remission at week 12 maintained that status to the end of therapy.

In phase II, randomized, double-blind, placebo-controlled trial in ulcerative colitis patients (OASIS), etrasimod 2 mg displayed good tolerability and yielded substantial benefits compared to placebo. An open-label extension study by Séverine Vermeire et al. was performed to investigate the efficacy and safety of once-daily 2 mg etrasimod (an oral, selective, sphingosine 1-phosphate receptor modulator) in attaining and maintaining clinical response and/or remission in individuals who completed the OASIS.

In OASIS, 156 participants were administered 1 mg etrasimod, 2 mg etrasimod, or placebo once-daily for about 12 weeks. After completing OASIS, participants could enroll in the open-label extension study and receive 2 mg etrasimod for a further 34-40 weeks.

In total, 118 participants were recruited in the open-label extension study; 112 subjects received 2 mg etrasimod at any point and were assessed for efficacy and safety. Notably, 92 (82%) subjects who were administered 2 mg etrasimod in the open-label extension completed the study.

About 94% of treatment-emergent adverse events were mild-to-moderate, and no novel safety signals were witnessed. The adverse effects were found to occur in 60% (67/112) of individuals receiving 2 mg etrasimod at any time, most commonly anaemia and deteriorating ulcerative colitis. At the end of therapy, 64% of participants fulfilled the criteria for clinical response, 43% for endoscopic improvement, and 33% for clinical remission.

The week 12 clinical remission, clinical response, or endoscopic improvement was sustained/maintained to the end of therapy in 60% (15/25), 85% (39/46), or 69% (20/29) of patients, respectively.

In 22% of overall patients, steroid-free clinical remission was found to occur. Endoscopic improvement, clinical response, and remission noted with etrasimod at Week 12 in the OASIS trial was sustained (or improved) for up to 52 weeks in most individuals participating in the open-label extension study.

Etrasimod displayed a good safety profile and tolerability with a large majority of participants remaining on therapy over one year of therapy. Thus, this study offers support for sustained therapeutic benefits and a long-term safety profile of etrasimod to manage individuals suffering from ulcerative colitis.