Dr Reardon said there is a clear advantage that has been demonstrated across multiple clinically important endpoints including overall survival (OS), long-term progression-free survival (PFS), objective response rate (ORR) and need for steroids. The study showed that 33% of patients on the vaccine arm who were receiving steroids at baseline were able to stop steroids for 6 months or longer compared to none on the control arm.
Dr Reardon said the long-term survival benefit observed in this study is unprecedented as it is exceedingly rare for patients with highly aggressive, EGFRvIII-positive glioblastoma, even in the newly diagnosed setting, to live beyond 2 years. In addition, he said patients are also living better, with minimal side effects and potentially a reduced need for steroids.
The most common adverse events for rindopepimut include injection site reactions, fatigue, rash, nausea, and pruritus. “Side effects from rindopepimut are minimal, very mild redness around the injection site of the vaccine that fades in a few days,” said Dr Reardon.
Co-study author David Tran, MD, PhD, of the Department of Neurosurgery at the University of Florida in Gainesville, said this study is remarkable because it showed this approach is not associated with significant side effects and its effectiveness appears to be even greater than anticipated.
“We are pleasantly surprised with the results,” Dr Tran said in an interview with Cancer Therapy Advisor. “We were hoping immunotherapy would work to some extent, but we didn’t know it would have such a dramatic effect. This kind of survival benefit is surprising.”
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He believes this is just the first vaccine product of its kind that will be used in this patient population. Dr Tran said advancements in technology are going to lead to similar vaccines that are even more targeted and potentially more effective.
“This opens the door. If immunotherapy is designed correctly and designed against the right targets, it may prolong life. So, it gives us a lot of hope that we are moving in the right direction. This is a beginning,” said Dr Tran.
Editor’s note: The overall hazard ratio originally listed in this article was out of date. The number was updated on this site on December 17, 2015.
- Reardon DA, Desjardins A, Schuster J, et al. ReACT: long-term survival from a randomized phase II study of rindopepimut (CDX-110) plus bevacizumab in relapsed glioblastoma. Oral presentation at: 20th Annual Scientific Meeting and Education Day of the Society for Neuro-Oncology; November 19-22, 2015; San Antonio, TX. Abstract IMCT-08.