Phase II Clinical Study to Compare the Efficacy and Safety of HLX07 + Serplulimab +Chemotherapy Versus Placebo + Serplulimab + Chemotherapy in First-Line Treatment of Patients With Recurrent or Metastatic NPC

Inclusion Criteria: 1. Voluntarily participate in the clinical study; fully understand, be informed about the study, and have signed the informed consent form (ICF); be willing to follow and be able to complete all trial procedures. 2. Males or females aged ≥ 18 years at the time of signing the ICF. 3. Histologically or cytologically proven recurrent or metastastic NPC. 4. At least one measurable target lesion is assessed by the IRRC according to the RECIST v1.1 within 4 weeks prior to randomization. 5. An ECOG performance status score of 0-1 within 7 days prior to the first dose of the investigational product. 6. An expected survival period ≥ 12 weeks. Exclusion Criteria: 1. Other active malignancies within 3 years prior to the first dose of investigational product. Localized tumors that have been cured such as superficial bladder carcinoma, prostate carcinoma in situ, cervical carcinoma in situ, and breast cancer in situ are acceptable. 2. Patients who are going to receive or have received an organ or bone marrow transplant. 3. With uncontrolled pleural effusion, pericardial effusion, or ascites requiring frequent drainage (monthly or more frequently). 4. With cerebrovascular accident, myocardial infarction, unstable angina, poorly controlled arrhythmia (including QTc intervals ≥ 450 ms for males and ≥ 470 ms for females) (QTc intervals are calculated by Fridericia formula) within half a year. 5. Class III to IV cardiac insufficiency according to New York Heart Association (NYHA) classification (Appendix 5) or an LVEF (left ventricular ejection fraction) \< 50% by cardiac color Doppler. 6. Inadequately controlled hypertension (systolic blood pressure ≥ 150 mmHg and/or diastolic blood pressure ≥ 100 mmHg). 7. With human immunodeficiency virus (HIV) infection.