Dr. Mark Gilbert, a professor at the University of Texas MD Anderson Cancer Center's Department of Neuro-Oncology, said the findings are important because some doctors have been using Avastin as a frontline treatment for their brain-cancer patients.
"Obviously, glioblastoma is a cancer with too few effective therapies," Gilbert, who also holds the Blanche Bender Professorship in Cancer Research, said in a statement. "Bevacizumab, or Avastin, recently received approval in the second-line -- recurrent disease -- setting, and we knew some physicians were already giving the drug as a frontline therapy -- even with virtually no data to support that decision. It was important from a patient care and regulatory standpoint that we conduct this trial."
He noted glioblastoma is the most common and lethal form of brain cancer with an average survival rate of less than 18 months.
The Phase III, randomized, double-blind, placebo-controlled study registered 978 and enrolled 637 patients, respectively, all of whom were newly diagnosed with glioblastoma.
Participants underwent surgery to resect some or most of the tumor, received the standard of care of chemo-radiation with temozolomide, and were randomized to receive either bevacizumab or placebo. The study was designed with two primary endpoints: progression-free survival and overall survival.
The study, published in the New England Journal of Medicine, found no difference in overall survival between the bevacizumab and placebo arms, 15.7 and 16.1 months, respectively. When looking at the molecular markers, no subgroup of patients that benefited from bevacizumab could be identified, Gilbert said.
However, bevacizumab was associated with a higher rate of toxicities, including hypertension, bleeding, deep vein thrombosis and pulmonary embolism and gastrointestinal perforation.
Those on the therapy also experienced increase rates of symptom burden and neurocognitive decline, as well decreased quality of life, compared to those on placebo, Gilbert said.
Gilbert presented the findings at the American Society of Clinical Oncology annual meeting.