Complications of a temozolomide overdose: a case report

Purpose and background This is a report of a 53 year-old man with a glioblastoma multiforme (GBM) treated with an excessive dose of temozolomide (TMZ). Methods This is a single case review of all clinically relevant records. O-6-methylguanine-DNA methyltransferase activity was determined by a biochemical assay. Results Following conventional radiotherapy (RT) without concurrent chemotherapy, the patient received 5,500 mg of TMZ over 2 days. At the standard dose of 200 mg/m(2)/day his total 5-day dose should have been 1,940 mg. Acutely he had nausea, vomiting and diarrhea for 2 days which cleared. The dominant severe toxicity was pancytopenia between one and four weeks after TMZ which was complicated by secondary infections that were successfully managed. Transient transaminitis occurred but there were no significant pulmonary, renal or other systemic toxicities. His progression free survival was 22 months and overall survival 24 months. Conclusion His outcome suggests that TMZ may prove to be a good agent for dose-escalation trials with hematopoietic stem cell rescue.