Clinicians may soon have an important new tool for treating patients with EGFRvIII-positive, recurrent glioblastoma (GBM). An experimental therapeutic vaccine appears to improve survival as an add-on therapy.

New data from a randomized, double-blind phase 2 study of rindopepimut in patients with epidermal growth factor receptor variant III (EGFRvIII)-positive recurrent GBM presented at the 20th Annual Scientific Meeting of the Society for Neuro-Oncology (SNO) showed a marked benefit in terms of overall survival (hazard ratio, 0.53).1

Rindopepimut is an investigational EGFRvIII-specific therapeutic vaccine and was granted Breakthrough Therapy Designation by the U.S. Food and Drug Administration in February 2014.

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ReACT is a randomized, controlled phase 2 exploratory study designed to determine if adding rindopepimut to standard of care bevacizumab improves outcomes for patients with EGFRvIII-positive GBM across multiple measures. In this study, 73 patients who were bevacizumab-naïve at study entry were enrolled.

Patients with recurrent disease who express the EGFRvIII mutation typically have a worse prognosis than the overall glioblastoma population, including poor long-term survival. The median time from recurrence to death for EGFRvIII-positive patients is 8.7 months, according to lead study author of the ReACT study David Reardon, MD, who is the clinical director of the Center for Neuro-Oncology at the Dana-Farber Cancer Institute and an associate professor of medicine at Harvard Medical School, Boston, MA.

“This is a major step forward. It is the first immunotherapeutic to improve survival against these devastating tumors when assessed in a randomized, controlled clinical trial. Furthermore, it inspires hope that additional immunotherapies may also be able to help improve outcome for this desperate unmet need in medical oncology today,” Dr Reardon told Cancer Therapy Advisor.

Dr Reardon said this new vaccine may offer patients and their families new hope in the face of one of the most difficult to treat cancers. Nine of 10 patients (1 patient lost to follow-up) on the vaccine arm remain alive since the last presented data in May compared with only 2 out of 5 patients on the control arm.

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He said these results are changing the way clinicians view glioblastoma, and that these findings put to bed the notion that the brain, masked behind the blood-brain barrier, is beyond the reach of the promise of immunotherapy.

The study demonstrated that at 2 years, the survival rate for vaccine-treated patients was 25% vs 0% for control patients in the intent-to-treat (ITT) population.