This is an open-label, single-arm, phase I/II trial of immune checkpoint inhibitor combined with pemetrexed intrathecal injection for leptomeningeal metastasis from solid tumors.

This is an open-label, single-arm, phase I/II trial of immune checkpoint inhibitor combined with pemetrexed intrathecal injection for leptomeningeal metastasis from solid tumors. The primary objective was to assess recommended dose and safety based on adverse events (AEs). All participants were observed to evaluate the clinical response rate (CRR), disease control rate (DCR) and overall survival (OS). Patients underwent cerebrospinal fluid (CSF) and blood specimen collection to evaluate potential clinical, molecular, and/or immune predictors of treatment efficacy and safety.

Inclusion Criteria:

1. Histologically or cytologically confirmed diagnosis of solid tumors; Cerebrospinal fluid cytopathology is positive.
2. Male or female aged between 18 and 75 years; Normal liver and kidney function; WBC≥4000/mm3, Plt≥100000/mm3.
3. No history of severe nervous system disease; No severe dyscrasia.

Exclusion Criteria:

1. Any evidence of nervous system failure, including severe encephalopathy, grade 3 or 4 leukoencephalopathy on imaging, and Glasgow Coma Score less than 11.
2. Any evidence of extensive and lethal progressive systemic diseases without effective treatment.
3. A history of HIV or AIDS, acute or chronic hepatitis B or C infection, previous anti-PD1 therapy-induced pneumonitis, or have ongoing >Grade 2 adverse events of such therapy; or ongoing autoimmune disease that required systemic treatment in the past 2 years.
4. Patients with poor compliance or other reasons that were unsuitable for this study.

All individual participant data that underlie results in a publication will be available to other researchers.

Starting 6 months after publication

Individual participant data will be public accessable via contacting with principal investigator by email within 6 months after the trial complete