A Clinical Study to Evaluate the Efficacy and Safety of SI-B001 in the Treatment of Recurrent and Metastatic HNSCC

Inclusion Criteria:

1. Sign the informed consent voluntarily and comply with the requirements of theprogram;

2. Age ≥18; Gender is not limited;

3. Expected survival time ≥3 months;

4. Locally advanced squamous cell carcinoma of the head and neck confirmed by histologyor pathology as recurrent metastatic or without indications of radical localtreatment;

5. Patients who failed or were intolerant to previous anti-PD-1 mab andplatinum-containing chemotherapy

• Treatment failure of PD-1 refers to disease progression during or after PD-1treatment.

• Failure of platinum-containing chemotherapy refers to:

1. disease progression during or after platinum-containing chemotherapy;

2. recurrence or disease progression within 6 months of platinum-containingmulti-mode therapy;

3. Agree to provide tumor tissue samples (FFPE block or 10 unstained sections of 5μmsize) or fresh tissue samples archiving within one year from primary or metastaticfoci. If the patient fails to provide the samples, they can be included after theinvestigator's judgment;

4. There must be at least one measurable lesion in accordance with the RECIST v1.1definition. Tumor lesions located in the area of previous radiotherapy or otherlocal regional treatment sites are generally not measurable unless there is definiteprogression of the lesion or the lesion persists three months after radiotherapy;

5. Physical fitness ECOG score 0 or 1;

6. Adverse reactions to previous antitumor therapy were restored to CTCAE 5.0 ≤1 (except for toxicity judged by the researchers to be of no safety risk, such as hairloss, grade 2 peripheral neurotoxicity, and stable hypothyroidism after hormonereplacement therapy);

7. Organ function levels must meet the following requirements and meet the followingstandards:

8. Bone marrow function: absolute neutrophil count (ANC) ≥1.5×109/L, plateletcount ≥75×109/L, hemoglobin ≥90 g/L;

9. Liver function: Total bilirubin TBIL≤1.5×ULN (total bilirubin ≤3×ULN inSubjects with Gilbert's syndrome, liver cancer or liver metastasis), AST andALT ≤2.5×ULN in patients without liver metastasis, AST and ALT ≤5.0×ULN inpatients with liver metastasis;

10. Renal function: creatinine (Cr) ≤1.5×ULN, or creatinine clearance (Ccr) ≥50mL/min (according to Cockcroft and Gault formula);

11. Urine routine / 24-hour protein quantification: qualitative urine protein ≤1+ (if qualitative urine protein ≥2+, 24-hour protein < 1g can be included in thegroup);

12. Cardiac function: left ventricular ejection fraction ≥50%;

13. Coagulation function: International standardized ratio (INR) ≤1.5×ULN, andactivated partial thrombin time (APTT) ≤1.5×ULN;

14. Eligible fertile patients (male and female) must agree to use a reliablecontraceptive method (hormonal or barrier method or abstinence, etc.) with theirpartner during the trial period and for at least 6 months after the last medication;Women of childbearing age must have a negative blood or urine pregnancy test within 7 days prior to the first use of the study drug.

Exclusion Criteria:

1. Squamous cell carcinoma with primary site of nasopharynx or skin;

2. Have received chemotherapy, radiotherapy, biotherapy, endocrine therapy,immunotherapy and other anti-tumor therapy within 4 weeks prior to the first use ofthe study drug, except the following:

• Nitrosorea or mitomycin C within 6 weeks before the first administration of thestudy drug;

• Oral fluorouracil and small molecule targeted drugs are 2 weeks before thefirst administration of the study drug or within the 5 half-lives of the drug (whichever is longer);

• The traditional Chinese medicines with anti-tumor indications were within 2weeks before the first use of the study drug;

3. Received an unmarketed clinical investigational drug or treatment within 4 weeksprior to the first use of the investigational drug;

4. Has undergone major organ surgery (excluding needle biopsy, tracheotomy,gastrostomy, etc.) or has significant trauma within 4 weeks before the first use ofstudy drugs, or needs to undergo elective surgery during the trial;

5. Previous recipients of allogeneic hematopoietic stem cell transplantation or organtransplantation;

6. A history of serious cardiovascular and cerebrovascular diseases, including but notlimited to:

• Severe cardiac rhythm or conduction abnormalities, such as ventriculararrhythmias requiring clinical intervention, grade iii atrioventricular block,etc.

• In the resting state, QT interval was prolonged (QTc > 450 msec in men or QTc > 470 msec in women).

• Acute coronary syndrome, congestive heart failure, aortic dissection, stroke orother grade 3 or higher cardio-cerebrovascular events within 6 months prior tothe first administration;

• New York Heart Association (NYHA) heart function grade ≥II heart failure;

7. Active autoimmune diseases and inflammatory diseases, such as: systemic lupuserythematosus, systemic treatment of psoriasis, rheumatoid arthritis, inflammatorybowel disease, and hashimoto's thyroiditis, etc., with the exception of type Idiabetes, only replacement therapy can control the hypothyroidism, no systemictreatment of skin disease (e.g., vitiligo, psoriasis);

8. A history of other malignancies within 5 years prior to first administration, exceptfor radical basal cell carcinoma of the skin, squamous cell carcinoma of the skinand/or radical excised carcinoma in place, and second primary squamous cellcarcinoma of the head and neck;

9. Poorly controlled hypertension (systolic blood pressure & GT; 150 mmHg or diastolicpressure &gt; 100 mmHg);

10. Pulmonary disease defined as grade 3 or higher according to CTCAE V5.0; Patientswith past or present interstitial lung disease (ILD);

11. Cerebral parenchymal or meningeal metastases with clinical symptoms are not suitablefor inclusion by the investigator;

12. Experienced ≥ grade 3 infusion-related reactions during previous anti-EGFR antibodytherapy;

13. Human immunodeficiency virus antibody (HIVAb) positive, active tuberculosis, activehepatitis B virus infection (HBV-DNA copy number > 104) or hepatitis C virusinfection (HCV-RNA > center detection lower limit);

14. Active infections requiring systemic treatment, such as severe pneumonia,bacteremia, sepsis, etc.;

15. Pregnant or lactating women;

16. Persons with mental disorders or poor compliance;

17. The investigator considers that the subject has a history of other serious systemicdiseases or other reasons and is not suitable to participate in this clinical study