Paclitaxel poliglumex (PPX), a drug conjugate that links paclitaxel to poly-L-glutamic acid, is a potent radiation sensitizer. Prior studies in esophageal cancer have demonstrated that PPX (50 mg/m2/wk) can be administered with concurrent radiation with acceptable toxicity. The primary objective of this study was to determine the safety of the combination of PPX with temozolomide and concurrent radiation for high-grade gliomas.
Eligible patients were required to have WHO grade 3 or 4 gliomas. Patients received weekly PPX (50 mg/m2/wk) combined with standard daily temozolomide (75 mg/m2) for 6 weeks with concomitant radiation (2.0 Gy, 5 d/wk for a total dose of 60 Gy).
Twenty-five patients were enrolled, 17 with glioblastoma and 8 with grade 3 gliomas. Seven of 25 patients had grade 4 myelosuppression. Hematologic toxicity lasted up to 5 months suggesting a drug interaction between PPX and temozolomide. For patients with glioblastoma, the median progression-free survival was 11.5 months and the median overall survival was 18 months.
PPX could not be safely combined with temozolomide due to grade 4 hematologic toxicity. However, the favorable progression-free and overall survival suggest that PPX may enhance radiation for glioblastoma. A randomized study of single agent PPX/radiation versus temozolomide/radiation for glioblastoma without MGMT methylation is underway.