Paclitaxel Polymersomes + Carboplatin + Adebelimab: Neoadjuvant Phase Ⅱ Single-Arm Study for Resectable Mucosal Melanoma

Inclusion criteria

• Age ≥ 18 years old.
• Histopathologically confirmed resectable mucosal melanoma.
• Subjects must provide 5 formalin-fixed paraffin-embedded (FFPE) tissue sections collected before treatment, or be willing to undergo needle biopsy for pathological tissue acquisition to facilitate pathological assessment.
• ECOG (Performance Status, PS) score of 0-1.
• No prior treatment with immune checkpoint inhibitors such as anti-CTLA-4, anti-PD-1, or anti-PD-L1 monoclonal antibodies.
• No prior treatment with taxane-based drugs.
• Presence of measurable lesions (per RECIST 1.1 criteria).
• No history of immunosuppressant use within 6 months prior to enrollment.
• Hematological and biochemical test results meeting the following criteria:

i. Neutrophil count ≥ 1,500 × 10⁹/L; ii. Platelet count ≥ 100 × 10⁹/L; iii. Hemoglobin > 9.0 g/dL; iv. Serum creatinine ≤ 1.5 × upper limit of normal (ULN) or creatinine clearance (CrCl) ≥ 40 mL/min; v. Aspartate aminotransferase (AST)/Alanine aminotransferase (ALT) ≤ 3 × ULN; vi. Total bilirubin ≤ 1.5 × ULN.

• Women of childbearing potential must have a negative serum or urine pregnancy test and agree to use an appropriate contraceptive method (barrier contraception or oral contraceptives).

Exclusion criteria

• Presence of distant metastatic lesions.
• Active autoimmune disease. Note: Patients with vitiligo, type 1 diabetes mellitus, or Hashimoto's thyroiditis with hypothyroidism who only require hormone replacement therapy may be enrolled if there is no evidence of significant disease recurrence.
• Need for systemic corticosteroid therapy (> 10 mg prednisolone [or equivalent]/daily) or other immunosuppressant use within 14 days after enrollment. Note: Inhaled or topical corticosteroids, or adrenal hormone replacement therapy (> 10 mg prednisolone [or equivalent]/daily) are acceptable for patients without obvious autoimmune diseases.
• Concurrent diagnosis of other malignant tumors requiring anti-tumor treatment. Note: Patients may be considered for enrollment if the other malignant tumor has achieved complete remission for 2 years or more and no additional anti-tumor treatment is required during the study period.
• Patients who are medically, psychologically, or physically unable to complete the study or understand the information provided in the patient brochure, as assessed by the investigator.
• Prior treatment with anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CTLA-4, or other drugs targeting T-cell costimulatory or immune regulatory pathways.
• Prior chemotherapy with taxane-based drugs.
• Positive HIV test result or confirmed diagnosis of acquired immunodeficiency syndrome (AIDS).
• Known hypersensitivity to the study drugs.
• Pregnant or lactating women.