This study aims to evaluate the efficacy, safety, pharmacokinetics (PK) and immunogenicity of 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.