A Phase II Clinical Trial to Evaluate the Efficacy and Safety of TQH3906 Capsules in the Treatment of Active Psoriatic Arthritis

Inclusion Criteria: * Sign a written Informed Consent Form, which must meet the following requirements * Be willing to participate in the study and able to sign the informed consent form; * Be willing and able to complete all study-specific procedures and visits; * PsA trial participant disease characteristics * Aged 18 to 70 years（inclusive）; * BMI ≥ 18 kg/m² at screening; diagnosed with PsA for at least 3 months prior to screening, and meeting the Classification Criteria for Psoriatic Arthritis (CASPAR) at screening; * Active arthritis at screening and at baseline (Day 1); * Has failed or was intolerant to at least one prior therapy; * If receiving a conventional synthetic Disease-Modifying Antirheumatic Drug (csDMARD), trial participants must be on only one DMARD, which must have been administered for at least 3 months prior to screening, with a stable dose for at least 28 days prior to the first dose; * If using NSAIDs, the dose must have been stable for at least 14 days before the first dose; * If using oral corticosteroids, the dose must have been stable for at least 14 days before the first dose; * Topical treatments for plaque psoriasis must have remained stable for at least 14 days before the first dose; * Women of childbearing potential must agree to use effective contraception during the study and for 6 months after the end of the study; men must agree to use effective contraception during the study and for 6 months after the end of the study…