Focusing on Intrathecal Pemetrexed for Treating Leptomeningeal Metastases From NSCLC

Intrathecal chemotherapy is one of the mainstay treatment options for leptomeningeal metastases (LMs). In 2019 and 2020, intrathecal pemetrexed (IP) at a 10 mg dose on a schedule of 1 to 2 times per week presented good efficacy and safety in the cerebrospinal fluid (CSF) in a phase 1 study and a phase 1 and 2 study, respectively.1,2 Recently, I read with great interest the article by Fan et al.3 focusing on IP for tyrosine kinase inhibitor (TKI)-failed LMs from EGFR-mutant NSCLC. Nevertheless, I think it is very important to point out some major issues and concerns regarding the study design, study medication, medical ethics, and study data.