New combo therapy aims to stop oral cancer from coming back

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Aged 18 to 75 years at the time of enrollment. * ECOG Performance Status (PS) score of 0-1. * Primary lesion pathologically confirmed as oral squamous cell carcinoma (OSCC), including tumors of the anterior two-thirds of the tongue, gingiva, buccal mucosa, floor of the mouth, hard palate, or retromolar trigone. * Clinical stage III or IVA, defined as T1-2 with N1-2, or T3-4a and/or N0-2, according to the AJCC 8th edition OSCC TNM staging system. * Willingness to undergo surgical treatment. * Presence of at least one measurable lesion as defined by RECIST v1.1 criteria. * Voluntary participation with full understanding and signing of the informed consent form, and willingness to comply with study procedures. * Adequate major organ function, meeting all of the following laboratory criteria: * 1\. Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L without granulocyte colony-stimulating factor (G-CSF) administration within 14 days prior to testing. * 2\. Platelet count ≥ 100 × 10⁹/L without blood transfusion within the previous 14 days. * 3\. Hemoglobin \> 90 g/L without blood transfusion or erythropoietin use within the previous 14 days. * 4\. Total bilirubin ≤ 1.5 × the upper limit of normal (ULN); ≤ 3 × ULN in cases of Gilbert's syndrome or non-hepatic indirect bilirubin elevation. * 5\. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN; ≤ 5 × ULN for patients with hepatic involvement. * 6\. Serum creatinine ≤ 1.5 × ULN and creatinine clearance (calculated by the Cockcroft-Gault formula) ≥ 60 mL/min. * 7\. Adequate coagulation function, defined as INR or prothrombin time (PT) ≤ 1.5 × ULN. * 8\. Normal thyroid function, defined as thyroid-stimulating hormone (TSH) within the normal range. Subjects with abnormal TSH may be enrolled if total T3 (or FT3) and FT4 are within normal limits. * 9\. Normal myocardial enzyme profile (minor laboratory abnormalities deemed clinically insignificant by the investigator are acceptable). * 10\. For women of childbearing potential, a negative urine or serum pregnancy test within 3 days prior to the first dose of study treatment (Cycle 1, Day 1) is required. If the urine test is indeterminate, a serum test must be performed. Non-childbearing women are defined as those who have been postmenopausal for at least one year or have undergone surgical sterilization or hysterectomy. * 11\. All participants (male or female) with reproductive potential must agree to use highly effective contraception (annual failure rate \<1%) during the entire treatment period and for at least 120 days after the last study drug dose or 180 days after the last chemotherapy dose. Exclusion Criteria: * Prior treatment targeting PD-1, PD-L1, PD-L2, or CTLA-4, or other therapies targeting T-cell costimulatory or immune checkpoint pathways. * Participation in another interventional clinical trial or use of an investigational drug or device within 4 weeks prior to the first dose. * History of radiotherapy involving the head, neck, or maxillofacial regions. * Use of traditional Chinese medicines or immunomodulatory agents with OSCC indications (e.g., thymosin, interferon, interleukin) within 2 weeks before first dosing; local therapy for pleural effusion control is permitted. * History of active autoimmune disease within the past 2 years requiring systemic therapy (e.g., corticosteroids or immunosuppressants). Exceptions include: * 1\. Hypothyroidism controlled with thyroid hormone replacement therapy. * 2\. Diabetes mellitus controlled with insulin. * 3\. Adrenal or pituitary insufficiency treated with physiologic doses of corticosteroids. * Use of immunosuppressive agents: * 1\. Systemic corticosteroid therapy within 1 week prior to the first dose is prohibited. * 2\. Use of other immunosuppressive drugs is prohibited. * 3\. Intranasal, inhaled, or topical corticosteroids are permitted. * 4\. Physiologic doses of corticosteroids (e.g., prednisone ≤10 mg/day or equivalent) are permitted. * Prior systemic antitumor therapy, except patients who have had ≥12 months of treatment-free interval between the last chemotherapy and initiation of neoadjuvant therapy. * Previous allogeneic organ or hematopoietic stem cell transplantation (excluding corneal transplantation). * Known hypersensitivity to sintilimab, carboplatin, cisplatin, nab-paclitaxel, or any of their excipients. * Failure to recover to baseline or ≤ grade 1 (except fatigue or alopecia) from adverse events or complications of prior interventions before enrollment. * Known human immunodeficiency virus (HIV) infection (HIV-1/2 antibody positive). * Untreated active hepatitis B infection (HBsAg positive with HBV-DNA above the ULN). Subjects meeting the following criteria may be enrolled: * 1\. HBV viral load \<1000 copies/mL (200 IU/mL) and receiving antiviral therapy during the study to prevent reactivation. * 2\. Subjects who are anti-HBc(+), HBsAg(-), anti-HBs(-), and HBV-DNA(-) do not require prophylactic antiviral therapy but must be closely monitored for viral reactivation. * Active hepatitis C infection (HCV antibody positive with HCV-RNA above the lower limit of detection). * Receipt of a live vaccine within 30 days prior to the first dose (inactivated vaccines, such as inactivated influenza vaccine, are permitted; intranasal live vaccines are not allowed). * Pregnant or breastfeeding women. * Presence of severe or uncontrolled systemic diseases, including but not limited to: * 1\. Cardiac disorders: severe arrhythmias (e.g., complete left bundle branch block, second-degree or higher atrioventricular block, ventricular arrhythmia, or persistent atrial fibrillation), unstable angina, or congestive heart failure (NYHA class ≥ II). * 2\. Vascular disorders: history of unstable angina, myocardial infarction, transient ischemic attack, or stroke within 6 months before enrollment. * 3\. Poorly controlled hypertension (systolic BP \>140 mmHg or diastolic BP \>90 mmHg). * 4\. Pulmonary disorders: noninfectious pneumonitis requiring corticosteroid therapy within 1 year prior to the first dose, or active interstitial lung disease. * 5\. Infectious diseases: active infections requiring systemic treatment, or severe uncontrolled infections. * 6\. Active pulmonary tuberculosis. * 7\. Gastrointestinal disorders: clinically active diverticulitis, intra-abdominal abscess, or intestinal obstruction. * 8\. Hepatic disorders: liver cirrhosis, decompensated liver disease, or acute/chronic active hepatitis. * 9\. Poorly controlled diabetes mellitus: fasting blood glucose (FBG) \>10 mmol/L. * 10\. Renal dysfunction: urine protein ≥++ on urinalysis and 24-hour urinary protein \>1.0 g. * 11\. Psychiatric disorders: severe mental illness that may affect treatment compliance. * Any other condition that, in the opinion of the investigator, makes the subject unsuitable for participation in this study.