Efficacy and Safety Evaluation of Oral Etrasimod Arginine as Induction and Maintenance Therapy in Moderately to Severely Active Crohn's Disease

The primary objective of this study is to evaluate the **safety**, tolerability, and efficacy of two doses of etrasimod as induction therapy in subjects with moderately to severely active **Crohn's Disease** (CD). This is clinically relevant as it aims to determine the optimal dosing strategy for etrasimod, potentially improving therapeutic outcomes for patients with this chronic inflammatory condition.

Secondary objectives include:

• Substudy A: To assess the long-term safety, tolerability, and efficacy of etrasimod, as well as its pharmacokinetic and pharmacodynamic effects, including changes in lymphocytes, C-reactive protein (CRP), and fecal calprotectin (FCP).
• Substudy 1: To evaluate the safety, tolerability, and efficacy of etrasimod and to identify etrasimod responders for further evaluation in maintenance therapy.
• Substudy 2: To assess the safety and tolerability of the selected etrasimod Phase 3 dose versus placebo as induction therapy and to identify responders for maintenance evaluation.
• Substudy 3: To evaluate the efficacy of etrasimod on sustained clinical remission, endoscopic response, endoscopic remission, and corticosteroid-free clinical remission, and to characterize its safety and tolerability as maintenance therapy.
• Substudy 4: To evaluate the long-term efficacy of etrasimod in subjects with moderately to severely active CD.

The clinical trial involves a total of **808 participants** diagnosed with **Crohn's Disease**, focusing on individuals with moderately to severely active conditions. The study population includes both male and female subjects, aged between **18 to 80 years**. Participants were selected based on their ability to provide informed consent and their compliance with protocol assessments. The trial specifically targets individuals who have had Crohn's Disease for at least three months, with involvement of the ileum and/or colon, and who have demonstrated an inadequate response, loss of response, or intolerance to at least one prior therapy, such as oral corticosteroids, immunosuppressants, TNFα antagonists, integrin receptor antagonists, or interleukin-12/23 antagonists. The study does not specify particular lifestyle considerations such as diet or physical activity. Both genders are included, and the trial acknowledges the inclusion of a vulnerable population. Participants must adhere to contraception requirements if of childbearing potential. The sponsor has not provided additional information regarding specific lifestyle factors or other demographic details.

The clinical trial is designed as a **randomized**, **double-blind**, parallel-group study to evaluate the efficacy and safety of oral Etrasimod Arginine as induction and maintenance therapy for individuals with moderately to severely active **Crohn's Disease**. The trial will involve the administration of Etrasimod Arginine in tablet form, with a maximum daily dose of 3 mg, over a treatment period of up to 274 days. The study will include a placebo group to assess the dose-response relationship and select an optimal dose for further development. The trial is expected to conclude by August 31, 2029, with recruitment having commenced on July 14, 2021.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as age, disease activity, and previous treatment responses. The primary endpoints include the proportion of subjects achieving an endoscopic response at specified weeks, while secondary endpoints focus on clinical remission and changes in disease activity scores. Follow-up visits will occur at regular intervals to monitor safety, tolerability, and efficacy, with assessments including endoscopic evaluations and clinical scoring. The end-of-study visit will finalize data collection and assess long-term outcomes.

Participant involvement is expected to last for the duration of the treatment period, with conditions for early termination including adverse events, non-compliance with study protocols, or withdrawal of consent. The trial aims to provide comprehensive data on the therapeutic potential of Etrasimod Arginine in managing Crohn's Disease, contributing to the development of effective treatment strategies for this chronic condition.

The clinical trial involves the administration of **Etrasimod Arginine Blue**, an investigational medication formulated as a **tablet**. The active substance in this medication is **etrasimod arginine**, a chemical compound developed by Pfizer Inc. The medication is administered orally, with a maximum daily dose of 3 mg. The treatment period extends up to 274 days. The primary objective is to evaluate the safety, tolerability, and efficacy of two doses of etrasimod as induction therapy in subjects with moderately to severely active **Crohn's disease**. Participant compliance is monitored throughout the trial to ensure adherence to the dosing schedule.

In addition to the experimental medication, the study includes a **placebo** group, referred to as **Etrasimod Arginine Blue Placebo**. This placebo is also administered in tablet form and is designed to match the experimental medication in appearance and administration route. The placebo serves as a comparator to assess the efficacy of the active treatment. The use of a placebo is critical in maintaining the double-blind nature of the study, ensuring that neither the participants nor the investigators are aware of the treatment assignments, thus minimizing bias in the assessment of outcomes.

The efficacy of oral Etrasimod as induction and maintenance therapy for moderately to severely active **Crohn's Disease** will be assessed through a series of primary and secondary endpoints. The primary endpoints include the proportion of subjects achieving an endoscopic response at Week 14 and Week 52, as well as the proportion of subjects reaching clinical remission as measured by the Crohn's Disease Activity Index (CDAI) at these timepoints. Secondary endpoints will evaluate additional parameters such as changes from baseline in the Simple Endoscopic Score for Crohn's Disease (SES-CD) and CDAI scores, Etrasimod plasma concentrations at specific timepoints, and changes in absolute lymphocyte count (ALC).

Data collection will occur at multiple timepoints, including Week 14 and Week 52, to capture both short-term and long-term efficacy outcomes. The study will utilize validated scales and laboratory tests to ensure the accuracy and reliability of the efficacy assessments. The trial is designed to evaluate the dose-response relationship of two doses of Etrasimod versus placebo, with the goal of selecting an optimal dose for further development based on efficacy and safety outcomes. The study will also monitor the proportion of subjects achieving clinical remission by patient-reported outcomes (PRO2) and endoscopic remission at specified intervals throughout the trial duration.