Pifenidone Prophylactic Therapy for Radiation Lung Injury in Patients Who Have Previously Received Immune Checkpoint Inhibitors

Inclusion Criteria: 1. The patients joined the study voluntarily and signed an informed consent form (ICF). They had good compliance and cooperated with follow-up; 2. Patients with lung cancer who had received at least 2 cycles of immunomonotherapy or combination systemic therapy (including PD-1 or PD-L1 immunocheckpoint inhibitors) within 6 months; 3. Age ≥ 18 years, no gender limit; 4. ECOG PS score: 0～1; 5. The expected survival time ≥ 3 months; 6. Use appropriate methods of contraception or surgical sterilization during treatment and for 3 years after treatment for men and women of reproductive age； 7. Appropriate biochemical indicators and organ function. Exclusion Criteria: 1. Currently participating in interventional clinical research and treatment, or receiving other research drugs or treatment with research equipment within 4 weeks before the first administration; 2. Accept solid organ or blood system transplantation; 3. Suffer from active autoimmune diseases that require hormone or immunomodulatory treatment, such as rheumatoid arthritis, ankylosing spondylitis, type I diabetes, psoriasis, vitiligo, immune-related thyroid dysfunction, etc. (hormone replacement Can be included after treatment is normal); 4. Suffer from acute or chronic infectious diseases, such as hepatitis B, hepatitis C, tuberculosis, and HIV; 5. Allergic to research drug ingredients; 6. Active infection or fever of unknown cause occurred during the screening period and before the first administration\> 38.5℃ (according to the judgment of the investigator, the subject can be included in the group due to fever caused by the tumor); 7. Suffer from uncontrolled clinical symptoms or diseases of the heart, such as:(1) Heart failure above NYHA II; (2) Unstable angina pectoris; (3) Myocardial infarction occurred within 1 year; (4) Patients with clinically significant supraventricular or ventricular arrhythmia requiring clinical intervention; 8. Suffer from high blood pressure and cannot be well controlled by antihypertensive medication (systolic blood pressure ≥150 mmHg or diastolic blood pressure ≥100 mmHg); 9. Abnormal blood coagulation function (INR\>2.0, PT\>16s), have a bleeding tendency or are receiving thrombolytic therapy, and allow preventive use of low-dose aspirin and low-molecular-weight heparin; 10. Obvious coughing up blood or hemoptysis of 10ml or more per day in the 2 months before enrollment; 11. Have significant clinically significant bleeding symptoms or have a clear bleeding tendency within 3 months before enrollment; 12. Have received anti-tumor monoclonal antibodies (mAb) within 4 weeks before using the study drug for the first time, or the adverse events caused by the previously received drug have not recovered (ie ≤ grade 1 or reached the baseline level). Note: Except for subjects with ≤ Grade 2 neuropathy or ≤ Grade 2 hair loss, if the subject has undergone major surgery, the toxic reaction and/or complications caused by the surgical intervention must be fully recovered before starting treatment; 13. The investigator judged other situations not suitable for inclusion in this study.