The purpose of this study is to find out the efficacy and safety of oral FXS5626 in participants with active, non-anterior (intermediate, posterior, or pan) non-infectious uveitis (NIU).

This study is a multicenter, randomized, double-blind, placebo-controlled study conducted in china, aimed at evaluating the efficacy, safety and tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of FXS5626 administered twice daily for 24 weeks in participants with active, non-anterior (intermediate, posterior, or pan) non-infectious uveitis(NIU).

This study plans to enroll 40 patients with active non-anterior NIU. Patients who sign the informed consent form will be screened according to the enrollment criteria, and randomly allocated into 3 groups in a 2:1:1 ratio. Participants in groups 1 and 2 will receive different doses of FXS5626. Participants in group 3 will receive placebo.

Inclusion Criteria:

1. Participants must be capable of understanding the trial procedures, voluntarily agree to participate, communicate effectively with the investigators, comply with all study requirements throughout the trial, and provide written Informed consent Form (ICF);
2. At screening visit, male or female paticipants aged 18-70 years (inclusive) ;
3. At screening visit, Body mass index (BMI) between 18 and 30 kg/m² (inclusive), with a body weight of ≥50 kg for males and ≥45 kg for females;
4. At screening, at least one eye was diagnosed with active non-infectious uveitis by the investigator, including non-infectious intermediate uveitis, posterior uveitis, or panuveitis;
5. Subject must have active disease at the screening and baseline visit, as defined by the presence of at least 1 of the following parameters in at least one eye despite at least 2 weeks of maintenance therapy with oral prednisone ≥ 10 mg/day to ≤ 60 mg/day (or oral corticosteroid equivalent):

1) Active, inflammatory, chorioretinal and/or inflammatory retinal vascular lesion 2) ≥ 2+ anterior chamber cells (Standardization of Uveitis Nomenclature [SUN] criteria) 3) ≥ 2+ vitreous haze (National Eye Institute [NEI]/SUN criteria) ; [6] Participants and their partners must have no plans for reproduction, sperm donation, or egg donation from the start of treatment until at least one month after the last dose of the investigational drug, and must voluntarily employ an effective method of contraception as determined by the investigator.

Exclusion Criteria:

1. Participants with isolated anterior uveitis;
2. Participants with macular edema as the sole clinical manifestation of intermediate uveitis, posterior uveitis, or panuveitis;
3. Participants with confirmed or suspected infectious uveitis, including but not limited to infectious uveitis due to Tuberculosis (TB), cytomegalovirus (CMV), Lyme disease, toxoplasmosis, Human T-Lymphotropic Virus Type 1 (HTLV-1), Whipple's disease and herpes simplex virus (HSV);
4. Participants with Histoplasmosis Syndrome (HS);
5. Participants with ocular masquerade syndrome, including but not limited to the following causes: trauma, lymphoma, ocular malignant tumor, or surgery;
6. Participants with serpiginous choroidopathy;
7. Participants with corneal or lens opacity that precludes visualization of the fundus in either eye or that likely requires cataract surgery during the duration of the trial;
8. Participants with severe vitreous opacity or other factors that precludes visualization of the fundus in either eye;
9. Participant with uncontrolled glaucoma, intraocular pressure of ≥ 25 mmHg and on ≥ 2 glaucoma medications or evidence of glaucomatous optic nerve injury; The sponsor provides the definitive and complete eligibility criteria in the study protocol.

Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)