PD-1 Inhibitor Plus Chemotherapy Followed by Immediate Versus Selective Re-irradiation for Locally Advanced Recurrent NPC

Nasopharyngeal carcinoma (NPC) is prevalent in Southern China, and 10~15% of patients experience local recurrence, which presents significant treatment challenges. PD-1 inhibitor plus gemcitabine-cisplatin (GP) has become the standard first-line therapy for recurrent/metastatic NPC. However, the survival benefit of adding sequential re-irradiation after GP + PD-1 in locally advanced recurrent nasopharyngeal carcinoma remains uncertain.This phase II randomized trial aims to compare immediate versus selective re-irradiation following PD-1 inhibitor plus GP in locally advanced recurrent NPC, to determine whether sequential re-irradiation provides additional survival benefit without excessive toxicity.

Inclusion criteria

• Age 18-70 years, any gender.
• Local recurrence (with or without regional recurrence) more than one year after radical treatment and unsuitable for surgery.
• Pathologically confirmed non-keratinizing nasopharyngeal carcinoma (WHO type II or III).
• Achieved complete response (CR) or partial response (PR) after 4-6 cycles of chemotherapy plus PD-1 inhibitor therapy.
• ECOG performance status 0-1.
• Expected survival ≥ 3 months.
• No prior radiotherapy, chemotherapy, immunotherapy, or biological therapy for recurrent nasopharyngeal carcinoma
• No contraindications to immunotherapy, chemotherapy, or re-irradiation.
• Adequate organ function within 14 days before first dose, defined as:

Hematology：Hemoglobin ≥ 90 g/L，ANC ≥ 1.5 × 10⁹/L，Platelet count ≥ 100 × 10⁹/L Renal Function：Creatinine ≤ 1.5 × ULN, or creatinine clearance (CrCl) / eGFR ≥ 60 mL/min Liver Function：Total bilirubin ≤ 1.5 × ULN，AST and ALT ≤ 2.5 × ULN, or ≤ 5 × ULN in the presence of liver metastases

• INR or PT ≤ 1.5 × ULN, unless on therapeutic anticoagulation and values within therapeutic range，APTT ≤ 1.5 × ULN, unless on therapeutic anticoagulation and values within therapeutic range.

Exclusion criteria

• Presence of grade 3 or higher late radiation toxicity (excluding skin, subcutaneous tissue, and mucosa) at the time of recurrence
• Prior anti-tumor therapy for recurrent nasopharyngeal carcinoma, including radiotherapy, chemotherapy, surgery, or immunotherapy.
• Prior treatment with PD-1/PD-L1 or CTLA-4 inhibitors.
• History of other malignancies within the past 5 years, except adequately treated basal cell carcinoma, squamous cell skin cancer, or in-situ cervical cancer.
• Active autoimmune disease or history of autoimmune disease requiring systemic treatment (e.g., corticosteroids, immunosuppressants) within the past 2 years, except for stable hypothyroidism, type 1 diabetes mellitus, or resolved childhood asthma/atopy.
• Known history of active pulmonary tuberculosis (TB). Suspected active TB must be excluded by chest X-ray, sputum examination, and assessment of clinical signs and symptoms.
• Hepatitis B: HBsAg positive with peripheral blood HBV DNA ≥ 1000 copies/mL
• Hepatitis C: HCV antibody positive, eligible only if HCV RNA is negative
• HIV infection
• Clinically significant cardiovascular disease (e.g., uncontrolled hypertension, unstable angina, myocardial infarction within 6 months, congestive heart failure ≥ NYHA class II, or serious arrhythmia).
• Interstitial lung disease, non-infectious pneumonitis, or history of ≥ grade 2 pneumonitis.
• Major surgery within 4 weeks before enrollment, or unhealed surgical wound.
• Pregnant or breastfeeding women, or those planning pregnancy during the study period.
• Known allergy or hypersensitivity to study drugs or their excipients.
• Any condition that, in the investigator's judgment, would interfere with trial participation or interpretation of results.