A Study to Investigate the Efficacy and Safety of NSI-8226 in Adults with Eosinophilic Esophagitis

Phase 2 study to evaluate the safety, tolerability, PK, immunogenicity, and pharmacodynamics of solrikitug in adult participants with eosinophilic esophagitis.

This is a 24-week randomized, double-blind, placebo-controlled Phase 2 clinical study with a 28-week extension to evaluate the safety, tolerability, PK, immunogenicity, and pharmacodynamics of 3 dose levels of solrikitug versus placebo on top of standard of care in adult participants with EoE.

Approximately 157 adult participants with EoE will be randomized at approximately 80 sites. Participants will receive solrikitug, or placebo, administered via subcutaneous injection at the study site, over a 24-week treatment period followed by a 28-week extension period. The study also includes a post-treatment follow-up period of 16 weeks.

Eligibility Criteria:
Key inclusion criteria

Part A

* Participant must be 18 to 75 years of age inclusive, at the time of signing the informed consent.
* Established diagnosis of EoE with a previous EGD and esophageal biopsy confirming diagnosis of EoE.
* Participants who have symptomatic EoE as defined by a history of on average at least 2 episodes of dysphagia per week in the 4 weeks prior to Screening.
* Must remain on a stabilized diet for at least 8 weeks prior to Visit 1 and during the course of the study.
* May be on any background PPI and/or STC, during the course of the study, as long as background medications have been stable for at least 8 weeks prior to the Screening and must agree to no changes to background medication or dosage unless medically indicated.
* Discontinuation of any marketed investigational drug or biologic (monoclonal or polyclonal antibody) within 30 days or 5 half-lives prior to screening, whichever is longer.
* Participants should have previously documented standard of care treatment, which could include PPI and/or STC and/or diet.

Part B

* Participants who have completed all Part A assessments, doses, and have current negative pregnancy test may have the option to participate in the extension portion of this study (Part B).

Key exclusion criteria

Part A

* Female participant who is pregnant or breastfeeding.
* Have a history or presence of any other gastrointestinal disorders such as active Helicobacter pylori infection, history of achalasia, hyper eosinophilic syndrome and eosinophilic granulomatosis with polyangiitis, esophageal varices, Crohn's disease, ulcerative colitis, inflammatory bowel disease, celiac disease, eosinophilic enteritis, gastritis, colitis, diverticulitis, irritable bowel syndrome, or other clinically significant gastrointestinal conditions as per Investigator discretion.
* Esophageal stricture that prevents the easy passage of a standard endoscope or any critical esophageal stricture that requires dilation at screening.
* Esophageal dilation performed within 8 weeks prior to screening.
* Participant has a known hypersensitivity to any component of the formulation of solrikitug, including any of the excipients, or a history of anaphylactic reaction to any therapeutic monoclonal antibody.

Part B

* Participants who, during Part A, developed a serious adverse event (SAE) and/or adverse event (AE) deemed related to study drug, which in the opinion of the investigator could indicate that continued treatment with study drug may present and unreasonable risk to the participant.
* Participants who became pregnant during Part A.
* Participants who are prematurely discontinued from study drug due to AE (patients who are prematurely discontinued from study drug due to lack of efficacy are eligible to enter Part B).
* Patients who did not undergo endoscopy with biopsies prior to receiving rescue treatment.