IMT-03 CLINICAL TRIAL FOR NEWLY DIAGNOSED MALIGNANT GLIOMA WITH WT1-W10 VACCINATION

OBJECT: Wilms’ tumor 1 (WT1) peptide vaccination is considered a potentially effective therapy against malignant glioma. We conducted a Phase I/II study to investigate the safety and feasibility of novel WT1 peptide (W10) vaccination therapy for patients with newly diagnosed malignant glioma. METHODS: WT1 vaccination therapy was performed for patients with malignant glioma who have undergone concurrent radiotherapy and temozolomide therapy. A mixture of WT1 peptide with inactivated pertussis whole cell vaccine was injected intradermally once a week for at least 12 weeks. RESULTS: Twenty-seven patients (12 men, 15 women; median 65 years) with the following tumors were enrolled: WHO grade IV (15), WHO grade III (12). PFS and OS of glioblastoma cases were 12.7 months 21.9 months, respectively. PFS of the MGMT unmethylated group was shorter than the methylated group. Interestingly enough, overall survival in the MGMT unmethylated group was not significantly different from the methylated group. Analysis of recurrent cases after immunotherapy showed decreased expression of WT1 antigen and increased Treg. They were suggested as a cause of treatment resistance. No serious adverse events were observed except for Grade 1 erythema at the injection sites. CONCLUSIONS: This study of a novel WT1 vaccination therapy demonstrated safety and feasibility in the management of newly diagnosed malignant gliomas.