A Study to Evaluate SHR-1139 Injection in Patients With Pyoderma Gangrenosum

Inclusion Criteria: 1. Aged ≥18 years at the time of signing the informed consent form, regardless of gender; 2. Confirmed as having ulcerative pyoderma gangrenosum (PG) with a PARACELSUS score of ≥10 points at screening; 3. At screening and baseline, having at least one measurable PG ulcer (defined as an ulcer with a measured area of ≥ 5 cm²); 4. The participant voluntarily signs the informed consent form before the initiation of any study-related procedures, is able to communicate smoothly with the investigator, and understands and is willing to strictly comply with the requirements of this clinical study protocol to complete the study; 5. Female participants of childbearing potential or male participants whose female partners are of childbearing potential have no plans for childbirth, sperm/egg donation from the time of signing the informed consent form, and voluntarily adopt highly effective contraceptive measures (including by the partner). Female participants must have a negative pregnancy test result during the screening period and before randomization and dosing, and must not be breastfeeding. Exclusion Criteria: 1. Non-pyoderma gangrenosum (PG) diseases presenting with other ulcers or other similar skin lesions at screening; 2. The measured area of the target PG ulcer exceeding 80 cm² at screening; 3. Participants with chronic, non-inflammatory PG wounds or ulcers judged by the investigator to be unresponsive to immunosuppressive therapy at screening; 4. Participants with active infection in the PG ulcer(s) at screening; 5. A history of lymphoproliferative disorders, including lymphoma or signs and symptoms of potential lymphoproliferative diseases; 6. A history of any active malignant tumor or malignant neoplasm within 5 years prior to the screening visit, except for curatively treated cutaneous squamous cell carcinoma, basal cell carcinoma, or carcinoma in situ of the uterine cervix; 7. Any condition judged by the investigator to interfere with the assessment of the study drug's safety and efficacy.