In the rindopepimut arm at 2 months, 50% of patients were able to stop taking corticosteroids versus 26% in the control arm. By ≥6 months, 33% of patients had reduced or stopped steroid use versus none with the control.
“Corticosteroid use and requirement is a very relevant endpoint for our patients,” said Reardon. “A higher number in the rindopepimut arm were able to come off and stay off steroids at 2 months and 6 months. Quite significant improvement relative to the control arm.”
The most frequently reported all-grade adverse events (AEs) experienced by patients in the rindopepimut arm versus the control were arthralgia (23% vs 5%, respectively), nausea (23% vs 11%), back pain (17% vs 8%), vomiting (17% vs 5%), diarrhea (17% vs 5%), and falls (17% vs 5%). In some incidences, AEs were lower in the rindopepimut arm versus the control, specifically for hemiparesis (6% vs 16%, respectively), hyperglycemia (9% vs 11%), and headaches (23% vs 24%).
The most frequently reported grade ≥3 AEs in the rindopepimut arm were convulsion (11%) and back pain (6%). For the control arm, grade ≥3 AEs consisted of hyperglycemia (8%), hypertension (8%), hemiparesis (5%), headache (5%), and fatigue (5%).
“We confirmed that this vaccine is quite safe and extremely well tolerated, here in the recurrent disease setting,” explained Reardon. “There were no unexpected toxicities, outside of what we would expect with bevacizumab. No serious AEs or discontinuation of treatment-related to AEs. Basically patients experienced a mild erythema at the injection site as the only consistent adverse event."
In February 2015, rindopepimut was granted a breakthrough therapy designation by the FDA for adult patients with GBM who tested positive for EGFRvIII. This indication was based on data from the phase II ReACT study along with data from the phase II ACT III study for patients with newly diagnosed GBM.
The phase III ACT IV study is currently exploring rindopepimut in newly diagnosed patients EGFRvIII-positive GBM. Following the first interim analysis of this study in June 2015, a data safety and monitoring board recommended the continuation of the study. The second-interim is schedule to occur in early 2016.
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. Presented at: 2015 Annual Meeting of the Society for Neuro-Oncology; November 19-22, 2015; San Antonio, TX. Abstract IMCT-08.
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