Adjuvant Rezvilutamide in Combination With Androgen Deprivation Therapy in Androgen Receptor-positive, High-risk Salivary Duct Carcinoma

• Rezvilutamide (Drug): Rezvilutamide 240 mg (3*80mg tablets) will be administered orally once daily with or without food.
• Leuprolide Acetate (Drug): The dose and frequency of administration will be consistent with the prescribing information in prostate cancer patients.

Primary outcomes

• 3-year disease-free survival (DFS) [36 months]: DFS is defined as the time from entry until disease recurrence or death

Secondary outcomes

• 3-year overall survival (OS) [36 months, 60 months]: OS is defined as the time from entry until death due to any cause
• 3-year disease-specific survival (DSS) [36 months, 60 months]: DSS is defined as the time from entry until disease-specific death
• 3-year distant-metastatic free survival (DMFS) [36 months, 60 months]: DMFS is defined as the time from entry until distant metastasis or death
• Adverse events [36 months]: Evaluate adverse events utilizing CTCAE V5
• 5-year disease-free survival (DFS) [60 months]: DFS is defined as the time from entry until disease recurrence or death

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Histologically confirmed salivary duct carcinoma and stage III or IVa or IVb according to AJCC Cancer Staging Manual Eighth Edition
* Completed SDC surgery, and adjuvant radiotherapy is planned or ongoing or has completed
* Androgen receptor (AR) positive
* White blood cell (WBC) ≥ 3.0 x 10\^9/L, Neutrophil count≥ 1.5 x 10\^9/L, Platelet count (PLT) ≥ 75 x 10\^9/L, Haemoglobin (Hb) ≥ 90 g/L
* Serum creatinine (Cr) < 1.5 x upper limit of normal(ULN) or creatinine clearance ≥ 50 ml/min.
* Total bilirubin (TBIL) < 1.5 x ULN, AST< 2.5 x ULN, and ALT< 2.5 x ULN
* Eastern Cooperative Oncology Group (ECOG) performance status 0, 1 or 2, and ability to take oral medication
* For females of reproductive potential: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation and for an additional 1 year after the end of study intervention administration
* For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner

Exclusion Criteria:

* Received prior anti-AR pathway therapy
* Treatment with another investigational drug or chemotherapy within 6 months
* History of hypothalamus or pituitary dysfunction
* History of seizure
* Clinically uncontrolled diseases, such as septic shock, uncontrolled hypertension, unstable angina, New York Heart Association (NYHA) class III or IV heart disease, clinically unstable arrhythmia, myocardial infarction (in the past 6 months)
* Previous cancer except skin cancer rather than malignant melanoma or any cancer curatively treated > 5 years prior to study entry
* Pregnancy or lactation