Avelumab With Radiotherapy in Patients With Leptomeningeal Disease

Inclusion Criteria: * 1\. Histologically or cytologically confirmed diagnosis of any cancer except leukemia * 2\. Patients must have the presence of malignant cells in the CSF (CSF+) OR at least 2 of the 3 following features: 1) clinical signs and symptoms of LMDz 2) characteristic radiographic abnormalities , and 3) "suspicious" CSF (Chamberlain 2017) * 3\. Patients must have an Eastern Cooperative Oncology Group performance scale of \< 3 OR Karnofsky Performance Status of \>50. * 4\. An interval of at least 2 weeks after the end of prior radiation therapy to the brain (e.g., stereotactic radiosurgery or other-WBRT is excluded) * 5\. An interval of at least 4 weeks following any surgical resection of brain lesions prior to treatment * 6\. Be \> 18 years of age on the day of signing consent * 7\. Demonstrate adequate organ function as defined in Table 2. All screening labs should be performed with 14 days of treatment initiation * 8\. Resting baseline O2 saturation by pulse oximetry of \> 92% at rest * 9\. Patients must have recovered from the toxic effects of prior therapies (\< Grade 1) * 10\. Provision of signed and dated informed consent form * 11\. Life expectancy of \> 8 weeks * 12\. Pregnancy test: negative serum or urine pregnancy test at screening for women of childbearing potential. * 13\. Contraception: Highly effective contraception for both male and female subjects throughout the study and for at least 30 days after last Avelumab treatment administration, if the…