Randomized, double-blind, phase III trial of a personalized peptide vaccination for human leukocyte antigen-A24-positive glioblastoma multiforme patients refractory to temozolomide-based therapy.

Abstract

2000 Background: To establish whether personalized peptide vaccination (PPV) is clinically beneficial for human leukocyte antigen (HLA)-A24-positive glioblastoma multiforme (GBM) patients refractory to temozolomide (TMZ)-based therapy. Methods: From January 2012 to March 2016, 88 HLA-A24-positive GBM patients refractory to TMZ-based therapy from 20 Japanese hospitals were randomly assigned to receive PPV treatment (n = 58) or best supportive care (BSC) (n= 30) at a 2 to 1 ratio. Four peptides chosen from 12 peptide candidates based on pre-vaccination IgG levels specific to each peptide or 4 corresponding placebos were injected subcutaneously once weekly for 12 times at the first course followed by biweekly vaccinations until disease progression. The primary endpoint was overall survival (OS). Results: The primary endpoint was not met in this clinical trial. Unfavorable prognostic factors were performance status (PS) 3, higher plasma levels of pre-vaccination granulocyte macrophage-colony stimulating factor (GM-CFS), and PPV containing SART2-derived peptides. Therefore, 78 patients with PS of 0 to 2 (50 with PPV and 28 with BSC) were provided for the subgroup analysis. Among them, the median OS of 39 PPV patients (10.4 months, 95% CI, 7.8-12.0 months) who had either lower levels of GM-CSF ( < 0.9 pg/mL) or 4 peptide vaccinations that did not include SART2-derived peptides was significantly (p = 0.03) longer than that of the corresponding 19 BSC patients (6.8, 4.6-12.7). In contrast, the median OS of 10 PPV patients (4.1, 1.1-8.3) who had both higher levels of GM-CSF ( > 0.9 pg/mL) and 4 peptide vaccinations containing SART2-derived peptides was significantly (p = 0.01) shorter than that of the corresponding 9 BSC patients (not reached, 1.6-not reached). A single grade 3 adverse event was the only PPV-related adverse event of grade > 3 in this study. Conclusions: PPV monotherapy could be a new treatment modality for HLA-A24-positive GBM patients refractory to TMZ-based therapy, since this approach showed clinical benefit and safety under precision medicine-based pre-vaccination selection of appropriate patients. Clinical trial information: UMIN000006970.