Intrathecal Pemetrexed for Recurrent Leptomeningeal Metastases From Non-small Cell Lung Cancer

Pemetrexed,10-15 mg, intrathecal injection via lumbar puncture, twice per week for 2 weeks, followed by once per week for 2-4 weeks.

Dexamethasone, 5 mg, intrathecal injection via lumbar puncture, simultaneously with pemetrexed, twice per week for 2 weeks, followed by once per week for 2-4 weeks.

Folic acid, 400 μg, oral, once per day, prior to the first intrathecal pemetrexed, until 21 days after the last intrathecal pemetrexed.

A single dose of vitamin B12 1000 μg, intramuscular injection, before the first intrathecal pemetrexed.