Takayasu arteritis (TKA) is an autoimmune vasculitis characterized with involvement of aorta and its primary branches.Upadacitinib is an oral, selective JAK1 inhibitor that potently inhibits JAK1 activity, representing a potential therapeutic option.This study aims to assess the efficacy and safety of upadacitinib in refractory Takayasu arteritis.

This is a single-arm trial conducted to evaluate the safety and efficacy of upadacitinib in refractory Takayasu arteritis (TKA). Patients in active TKA and unresponsive to at least 6 months of TNF-α inhibitors therapy were enrolled. Patients discontinued TNF-α inhibitors and received upadacitinib at 15 mg/day for up to 24 weeks, which was added to the glucocorticoid and immunosuppressants. The clinical manifestations, inflammatory indicators, imaging and treatment of patients were recorded by investigators during the follow up.

Inclusion Criteria:

• Male or female aged 18-70 years at time of screening. Diagnosis of Takayasu arteritis (according to the 2022 ACR/EULAR) for ≥3 months before screening.

Active Takayasu arteritis at time of screening (NIH score≥2). Resistant to traditional therapies and anti-TNF-α therapy for at least 6 months.

Given their written informed consent to participate in the trial and expected to be able to adhere to the study visit schedule and other protocol requirements.

Exclusion Criteria:

• TKA-related active major organ involvement requiring immunosuppressive therapy, e.g., pulmonary (e.g., pulmonary artery aneurysm), vascular (e.g., thrombophlebitis, recurrent malignant aneurysms), gastrointestinal (e.g., gastrointestinal ulcers), and central nervous system (e.g., meningoencephalitis).

High-dose glucocorticoid (>1mg/kg/d) usage within 1 month. Severe comorbidities: including heart failure (≥ grade III NYHA), renal insufficiency (creatinine clearance ≤30 ml/min), hepatic insufficiency (serum ALT or AST >3 times the ULN, or total bilirubin >ULN for the central laboratory conducting the test). Other severe, progressive or uncontrolled hematologic, gastrointestinal, endocrine, pulmonary, cardiac, neurologic, or cerebral disease (including demyelinating diseases such as multiple sclerosis).

Known allergies, hypersensitivity, or intolerance to Baricitinib or its excipients.

Had a severe infection (including, but not limited to hepatitis, pneumonia, sepsis, or pyelonephritis); had been hospitalized for an infection; or had been treated with IV antibiotics for an infection, within 2 months prior to the first administration of study agent.

Chest radiograph within 3 months prior to the first administration of study agent that showed an abnormality suggestive of a malignancy or current active infection, including tuberculosis.

Infected with HIV (positive serology for HIV antibody) or hepatitis C (positive serology for Hep C antibody). If seropositive, consultation with a physician with expertise in the treatment of HIV or hepatitis C virus infection was recommended.

Infected with hepatitis B virus. For patients who were not eligible for this study due to hepatitis B virus test results, consultation with a physician with expertise in the treatment of hepatitis B virus infection was recommended.

Had any known malignancy or has a history of malignancy within the previous 5 years (with the exception of a nonmelanoma skin cancer that had been treated with no evidence of recurrence for ≥3 months before the first study agent administration or cervical neoplasia with surgical cure).

Had uncontrolled psychiatric or emotional disorder, including a history of drug and alcohol abuse within the past 3 years that might prevent the successful completion of the study.

Received, or was expected to receive, any live virus or bacterial vaccination within 3 months before the first administration of study agent, during the study, or within 4 months after the last administration of study agent. Had a BCG vaccination within 12 months of screening.

Pregnancy, lactation or women of child-bearing potential (WCBP) unwilling to use medically approved contraception whilst receiving treatment and for 12 months after treatment has finished.

Men whose partners are of child-bearing potential but who are unwilling to use appropriate medically approved contraception whilst receiving treatment and for 12 months after treatment has finished.

Based on the inclusion and exclusion criteria, adult patients with refractory TAK admitted to Peking University People's Hospital and other hospitals were selected, and clinical and laboratory indicators during the same period were collected.