A Study of SI-B001+SI-B003 Combined With Platinum-based Chemotherapy as First-line Treatment in Patients With Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma

Inclusion Criteria: 1. Sign the informed consent form voluntarily and follow the protocol requirements; 2. Gender is not limited; 3. Age ≥18 years old and ≤75 years old; 4. Expected survival time ≥3 months; 5. Patients with recurrent or metastatic head and neck squamous cell carcinoma; 6. Consent to provide tumor tissue samples or fresh tissue samples archived from the primary or metastatic lesions within 2 years; 7. At least one measurable lesion meeting the RECIST v1.1 definition was required; 8. Physical status score: ECOG ≤1; 9. The toxicity of previous antineoplastic therapy has returned to ≤ grade 1 as defined by NCI-CTCAE v5.0; 10. No severe cardiac dysfunction, left ventricular ejection fraction ≥50%; 11. No blood transfusion or colony-stimulating factor was allowed within 14 days before the first use of the study drug, and the organ function level must meet the requirements; 12. Coagulation function: international normalized ratio (INR) ≤1.5, and activated partial thromboplastin time (APTT) ≤1.5×ULN; 13. Urinary protein ≤1+ or ≤1000mg/24h; 14. Fertile female subjects, or male subjects with fertile partners, must use highly effective contraception from 7 days before the first dose until 24 weeks after the dose. Female subjects of childbearing potential had to have a negative serum pregnancy test within 7 days before the first dose. Exclusion Criteria: 1. Squamous cell carcinoma of the nasopharynx, salivary gland, paranasal sinus, skin or of unknown primary site; 2. Patients with any of the following conditions were not eligible for the study: a) suitable and willing for local treatment; b) received systemic therapy, excluding treatment for locally advanced disease as part of multimodal therapy; 3. Patients with active central nervous system metastasis; 4. Who had participated in any other clinical trial within 4 weeks before the study dose; 5. Received radiotherapy within 4 weeks before the first dose of study drug; 6. Use of traditional Chinese medicine with anti-tumor indications within 2 weeks; 7. Had undergone major surgery within 4 weeks before the first dose; 8. Systemic corticosteroids or immunosuppressive agents were required within 2 weeks before study dosing; 9. Pulmonary disease was defined as ≥ grade 3 according to NCI-CTCAE v5.0; Patients with existing or a history of interstitial lung disease (ILD); 10. Have active infection requiring intravenous anti-infective therapy; 11. Had received immunotherapy and had grade ≥3 irAE or grade ≥2 immune-related myocarditis; 12. Received live attenuated vaccine within 4 weeks before the first dose of study drug; 13. Had taken an immunomodulatory drug within 14 days before the first dose of study drug; 14. Patients at risk for active autoimmune disease or with a history of autoimmune disease; 15. Other malignant tumors within 5 years before the first administration; 16. Human immunodeficiency virus antibody positive, active tuberculosis, active hepatitis B virus infection or hepatitis C virus infection; 17. Poorly controlled hypertension; 18. Patients with poor blood glucose control before the first dose; 19. Had a history of severe cardiovascular and cerebrovascular diseases; 20. Previous history of allogeneic stem cell, bone marrow or organ transplantation; 21. Patients with massive or symptomatic effusions or poorly controlled effusions; 22. Patients with a history of allergy to recombinant humanized antibodies or to any of the excipients of SI-B001 or SI-B003; 23. Had severe infusion reactions to antibody therapy in the past; 24. Had autologous or allogeneic stem cell transplantation; 25. Pregnant or lactating women; 26. The investigator did not consider it appropriate to apply other criteria for participation in the trial.