A Clinical Trial to Evaluate Safety of Gusacitinib in Patients With Systemic Lupus Erythematosus (SLE) or Lupus

Background: Systemic lupus erythematosus (SLE), also called lupus, is a disease that causes the body s immune system to attack healthy tissue. Lupus causes swelling and inflammation in the skin, skin, joints, kidneys, brain, blood vessels, and other organs. There is no cure for lupus. Current treatments do not help everyone and may have adverse effects. Better treatments are needed. Objective: To test a study drug (Gusacitinib) in people with lupus. Eligibility: People aged 18 years and older with lupus. Design: Participants will be screened. They will have a physical exam with blood and urine tests and a test of their heart function. They will have a chest X-ray. They will have tests that use blood pressure cuffs to measure blood flow and pressure throughout the body. Participants will have 9 clinic visits and 6 phone visits over about 7 months. The study has 3 parts. Part 1: Gusacitinib is a tablet taken by mouth. Participants will be divided into 3 groups. One group will receive the study drug, and a second group will get a placebo. The placebo looks like the study drug but does not contain any medicine. Both of these groups will take their tablets once a day for 12 weeks. The third group will continue to take their usual medications for lupus throughout the study. Part 2: All participants who took the study drug or placebo in part 1 will take the study drug once a day for 12 weeks. Part 3: All participants who took the study drug will stop taking it for 4 weeks.