In the randomized trial, Radiation Therapy Oncology Group (RTOG) 0525 Phase III Trial Comparing Conventional Adjuvant Temozolomide with Dose-Intensive Temozolomide in Patients with Newly Diagnosed Glioblastoma, no significant improvement in overall patient survival or disease progression was observed for patients who received the dose-intensive (dose-dense) TMZ plus radiotherapy as compared to patients who received standard-dose TMZ plus radiotherapy. The trial did prove the feasibility of collecting and analyzing tumor tissue prospectively in a multi-center setting.

The trial was led by RTOG principal investigator Mark R. Gilbert, MD, University of Texas M.D. Anderson Cancer Center, Houston, and conducted in concert with the European Organization for Research and Treatment of Cancer (EORTC) and the North Central Cancer Treatment Group (NCCTG).

“Given the promising preliminary data of improved patient outcomes using an adjuvant dose-intensive schedule of temozolomide, the trial allowed us to robustly test whether this treatment strategy provides a significant benefit over standard-dose temozolomide treatment,” says Gilbert. “While dose-dense temozolomide did not demonstrate improved efficacy for patients newly diagnosed with a glioblastoma, the study results confirmed the prognostic significance of MGMT gene methylation and demonstrated the feasibility of prospective tumor tissue collection, molecular stratification, and collection of patient outcomes in a large transatlantic intergroup trial.”

The clinical trial also included longitudinal data collection to measure neurocognitive function, symptom burden, and health-related quality of life, collectively called net clinical benefits. The important correlations of these measures with outcomes shown by the trial will be reported at the 2011 American Society of Clinical Oncology (ASCO) annual meeting in Chicago on June 4-8, along with seven presentations regarding other RTOG trials.