Intrathecal Dual Checkpoint Inhibitor (PD-1 and CTLA-4) in Combination With Pemetrexed for Leptomeningeal Metastasis

Intrathecal injection of PD-1/CTLA-4 bispecific antibody was administered every 2 weeks for 6 weeks during the induction phase, followed by monthly injections during the maintenance phase, until recurrence or death.

Pemetrexed (Alimta, Eli Lilly and Company) was administrated by intrathecal injection, first as induction therapy, twice per week for 2 weeks, followed by consolidation therapy, once per week for 4 weeks, then maintenance therapy, once per month until the patient's death, leptomeningeal metastasis progresses, or intolerable severe adverse events occurred.