Actual body weight dosing of temozolomide offers survival benefits in glioblastoma

Temozolomide administered to patients with glioblastoma at full actual body weight dosing during the concurrent phase is necessary to achieve a median overall survival (OS) that is similar to that seen in a previous trial, according to a recent study.

“Adult glioblastoma patients receiving standard radiation therapy and concurrent temozolomide chemotherapy have a median survival of 14.6 months,” the authors said. “Based on the pivotal trial data by Stupp [and colleagues], temozolomide doses were calculated based on body surface area (BSA).”

However, details regarding the weight used to calculate BSA were not included in the study. Because of this, doses of temozolomide had been inconsistent.

This retrospective chart review was done to verify the association between dose of first-line temozolomide with OS. The authors included patients who were newly diagnosed with pathology-confirmed glioblastoma between 1 January 2009 and 31 December 2018 and were treated with first-line temozolomide within Alberta Health Services.

Kaplan-Meier method used to compare temozolomide doses above and below the determined cut points. Doses were then assessed using the log-rank test.

A cut point of 97.8 percent of actual body weight calculated BSA dosing was established for concurrent phase temozolomide. Notably, a statistically significant increase of 0.3 years in median OS was observed at doses above the said cut point (p=0.0158).

In terms of adverse events, a statistically significant increase was seen in the proportion of temozolomide dose reductions due to toxicity in patients dosed above the cut point.