Evaluating High-dose Furmonertinib with Bevacizumab and Pemetrexed for EGFRm NSCLC with Leptomeningeal Metastasis

Inclusion Criteria: 1. Have obtained written informed consent from the patient or his or her legal representative; 2. The patient is ≥18 years old, male or female; 3. Non-small cell lung cancer confirmed by histological or cytological pathology; 4. Genetic testing confirming positive for classical or non-classical EGFR mutations; 5. After comprehensive clinical evaluation according to the "EANO-ESMO" meningeal metastasis diagnostic criteria, the comprehensive clinical evaluation of patients with definite meningeal metastasis included symptom evaluation, imaging evaluation, and/or cerebrospinal fluid pathology evaluation; 6. Patients with newly diagnosed leptomeningeal metastases and those with disease progression after previous antineoplastic therapy were eligible; 7. ECOG Performance Status 0-3; 8. Prior treatment with radiation or surgery targeting the central nervous system is permitted; 9. Admit patients with CNS symptoms or signs, but those symptoms or signs are not life threatening; 10. Fertile men or women with the possibility of becoming pregnant must use a highly effective method of contraception (such as oral contraceptives, intrauterine devices, abstinence or barrier contraception combined with spermicides) during the course of the trial and continue contraception for 12 months after the end of treatment. Exclusion Criteria: * 1)Patients currently have tumors other than NSCLC; 2)Have had or have a history of other malignancies within the last 5 years, other than basal cell carcinoma of the skin, carcinoma in situ of the cervix, and ductal carcinoma in situ of the breast that have been effectively controlled; 3)Serious digestive tract diseases that affect drug use and absorption, including but not limited to peptic ulcer, inflammatory bowel disease, etc. 4)Evidence of any severe or uncontrolled systemic disease, including uncontrolled hypertension, diabetes, and active bleeding, any that the investigator deems to be detrimental to the patient's participation in the study or to adherence to the protocol, or active infections including hepatitis B, hepatitis C, and human immunodeficiency virus (HIV); 5)A history of interstitial lung disease, drug-induced interstitial lung disease, prior history of radiation pneumonia requiring steroid treatment, or any evidence of active interstitial lung disease; 6)The presence of significant arrhythmias (such as prolonged QT interval \> 500ms) or heart failure (left ventricular ejection fraction \< 50%) 7)Pregnant or lactating women; 8)Patients who received a live vaccine within 4 weeks before treatment began; 9)Patients who are or have been involved in another clinical study within 4 weeks; 10)Other severe acute or chronic medical or psychiatric conditions or laboratory abnormalities that, in the investigator's opinion, may increase the risks associated with participating in the study or may interfere with the interpretation of the study results; Or subjects who may not be able to complete the study or comply with the requirements of the study (for administrative or other reasons).