A study to test different doses of BI 730357 and find out the effect they have on symptoms in people with active psoriatic arthritis

This trial is designed to evaluate safety, tolerability, PK and PD of BI 730357 in male and female patients with psoriatic arthritis using multiple escalation schemes and doses, and will support dose selection for phase 3 clinical development of BI 730357. Although effective treatments for psoriatic arthritis are approved, the unmet medical need remains for safer oral therapy that works well, improves joint and skin inflammation, prevents structural damage and maintains the efficacy over time. This trial is a randomised, double-blind, placebo-controlled trial in which three dose regiments of BI 730357 will be compared to placebo over a 12-week treatment period. Only approximately 40 patients out of total 160 patients will be randomized to receive placebo treatment. A placebo-control design is required for evaluation of evaluation of BI 730357 efficacy and safety. In addition, a placebo arm is needed in order to avoid potential confounding factors, such as placebo effect, potential investigator bias in safety and efficacy assessment or regression to the mean in endpoint scoring. In addition, as a risk mitigation strategy, if the patient experiences an intolerable increase in diseases activity of psoriatic arthritis during the course of the trial treatment, the patient will be discontinued from the trial treatment and will receive a standard of care treatment as deemed appropriate by the investigator.