Intrathecal Pemetrexed for Leptomeningeal Metastasis

Intrathecal chemotherapy is one of the most important treatment modalities for leptomeningeal metastasis of solid tumors. In the previous study(Intrathecal Pemetrexed for Recurrent Leptomeningeal Metastasis From Non-small Cell Lung Cancer: A Prospective Pilot Clinical Trial. ClinicalTrials.gov identification number: NCT03101579), pemetrexed presented feasibility of intrathecal administration. Pemetrexed at 10 mg dose level on the schedule of 1-2 times per week was recommended as an intrathecal administration agent for patients with refractory leptomeningeal metastases from non-small-cell lung cancer in the previous study. Moreover, the maximum-tolerated dose and recommended dose of intrathecal pemetrexed in the previous study was obtained without vitamin supplementation. Vitamin supplementation has been shown to reduce pemetrexed-induced myelosuppression. In this study, the regimen of intrathecal pemetrexed with folic acid and vitamin B12 supplementation may provide higher safety. Therefore, the purpose of this study is to investigate the maximally tolerated dose and evaluate the safety and effectiveness of intrathecal pemetrexed with vitamin supplementation as the first-line intrathecal chemotherapy in patients with leptomeningeal metastases from malignant solid tumors.

Sex

All

Minimum age

18 Years

Maximum age

75 Years

Inclusion Criteria:

1. Patients who have been definitely diagnosed as leptomeningeal metastasis according to cerebrospinal fluid cytology or neuroimaging, or patients who got the clinical diagnosis by combining with the history of cancer, clinical manifestation, cerebrospinal fluid examination, neuroimaging etc.;
2. Patients who have been diagnosed as malignant solid tumor according histopathology or cytopathology combined with imaging;
3. No prior intrathecal chemotherapy;
4. Normal liver and kidney function; WBC≥4000/mm3, Plt≥100000/mm3;
5. No other severe chronic diseases;
6. No history of severe nervous system disease;
7. No severe dyscrasia.

Exclusion Criteria:

1. Patients receiving molecularly targeted drugs that are effective in treating leptomeningeal metastases within 2 weeks prior to enrollment;
2. Patients with hydrocephalus or other factors suggestive of cerebrospinal fluid circulation obstruction;
3. patients with serious central nervous system disorders including severe encephalopathy, moderate or severe coma, and Glasgow Coma Score of \<8 points;
4. Patients who have been diagnosed as hematological malignancy or primary central germ cell tumor;
5. Other reasons that were unsuitable for this study, including patients with lethal or extensive systemic diseases with few treatment options,psychiatric illness and poor compliance.

• BACKGROUNDPan Z, Yang G, He H, Cui J, Li W, Yuan T, Chen K, Jiang T, Gao P, Sun Y, Cong X, Li Z, Wang Y, Pang X, Song Y, Zhao G. Intrathecal pemetrexed combined with involved-field radiotherapy as a first-line intra-CSF therapy for leptomeningeal metastases from solid tumors: a phase I/II study. Ther Adv Med Oncol. 2020 Jul 17;12:1758835920937953. doi: 10.1177/1758835920937953. eCollection 2020. PMID 32733606
• BACKGROUNDPan Z, Yang G, Cui J, Li W, Li Y, Gao P, Jiang T, Sun Y, Dong L, Song Y, Zhao G. A Pilot Phase 1 Study of Intrathecal Pemetrexed for Refractory Leptomeningeal Metastases From Non-small-cell Lung Cancer. Front Oncol. 2019 Aug 30;9:838. doi: 10.3389/fonc.2019.00838. eCollection 2019. PMID 31544065
• DERIVEDPan Z, Ye X, Huang Y, Tai P, Liu M, Sun X, Tang R, Gu A, Wang Z, Shen L, Pang X, Yuan T, Yang G. Intrathecal pemetrexed for newly diagnosed leptomeningeal metastases: a multicenter, open-label, phase I/II study. J Neurooncol. 2025 Nov;175(2):857-868. doi: 10.1007/s11060-025-05160-4. Epub 2025 Jul 23. PMID 40699526