Treatment of recurrent gliomas and metastatic brain tumors with a polydrug protocol designed to combat nitrosourea resistance

Abstract

Purpose: The study was undertaken to evaluate a chemotherapy protocol against recurrent malignant gliomas that was designed to combat presumed chloroethyl-nitrosourea (NU) resistance.

Patients and methods: All patients had malignant gliomas and had failed prior therapy. Patients were stratified as having either glioblastoma multiforme (GM) or anaplastic gliomas (AG) and as having failed radiotherapy (RT) only or both RT and chemotherapy. Chemotherapy consisted of six drugs: before lomustine (CCNU), thioguanine (TG), dibromodulcitol (mitolactol; DBD), and procarbazine (PCB) were given to enhance CCNU-induced tumor-cell kill and to reduce alkyltransferase repair of ethylated DNA. A fluorouracil-hydroxyurea (FUHU) combination was given 2 weeks later to kill cells that began to cycle after the challenge of the first four drugs (TPDC-FUHU chemotherapy).

Results: Of the 88 assessable patients, 37 had GM, 38 had AG, and 13 had other primary and metastatic brain tumors. For GM patients, 61% had a partial response (PR) or stable disease (SD) for a median of 9.3 months if RT only failed, and 58% had a PR or SD for a median of 5.1 months if they had previously been treated with an NU. For AG patients, 92% had a PR or SD for a median of 15 months if RT only had failed, but only 38% had a PR or SD for a median of 10.6 months if they had been previously treated with a NU. Activity was also seen against other recurrent or progressive primary and metastatic brain tumors.

Conclusions: TDPC-FUHU chemotherapy is a highly effective form of chemotherapy for both recurrent GM and AG patients. This study suggests but does not prove that this combination may be superior to other NU-based treatments for recurrent malignant glioma patients who fail RT. Because of the activity of this chemotherapy, we intend to evaluate more fully this approach in a randomized study.