• Shuichi Izumoto, Akihiro Tsuboi, Yoshihiro Oka, Tsuyoshi Suzuki, Tetsuo Hashiba, Naoki Kagawa, Naoya Hashimoto, Motohiko Maruno, Olga A Elisseeva, Toshiaki Shirakata, Manabu Kawakami, Yusuke Oji, Sumiyuki Nishida, Satoshi Ohno, Ichiro Kawase, Jun Hatazawa, Shin-Ichi Nakatsuka, Katsuyuki Aozasa, Satoshi Morita, Junichi Sakamoto, Haruo Sugiyama, and Toshiki Yoshimine.
• Department of Neurosurgery, Nagoya University, Nagoya, Japan. sizumoto@nsurg.med.osaka-u.ac.jp
• J. Neurosurg. 2008 May 1; 108 (5): 963-71.

ObjectThe object of this study was to investigate the safety and clinical responses of immunotherapy targeting the WT1 (Wilms tumor 1) gene product in patients with recurrent glioblastoma multiforme (GBM).MethodsTwenty-one patients with WT1/HLA-A*2402-positive recurrent GBM were included in a Phase II clinical study of WT1 vaccine therapy. In all patients, the tumors were resistant to standard therapy. Patients received intra-dermal injections of an HLA-A*2402-restricted, modified 9-mer WT1 peptide every week for 12 weeks. Tumor size, which was obtained by measuring the contrast-enhanced area on magnetic resonance images, was determined every 4 weeks. The responses were analyzed according to Response Evaluation Criteria in Solid Tumors (RECIST) 12 weeks after the initial vaccination. Patients who achieved an effective response continued to be vaccinated until tumor progression occurred. Progression-free survival and overall survival after initial WT1 treatment were estimated.ResultsThe protocol was well tolerated; only local erythema occurred at the WT1 vaccine injection site. The clinical responses were as follows: partial response in 2 patients, stable disease in 10 patients, and progressive disease in 9 patients. No patient had a complete response. The overall response rate (cases with complete or partial response) was 9.5%, and the disease control rate (cases with complete or partial response as well as those in which disease was stable) was 57.1%. The median progression-free survival (PFS) period was 20.0 weeks, and the 6-month (26-week) PFS rate was 33.3%.ConclusionsAlthough a small uncontrolled nonrandomized trial, this study showed that WT1 vaccine therapy for patients with WT1/HLA-A*2402-positive recurrent GBM was safe and produced a clinical response. Based on these results, further clinical studies of WT1 vaccine therapy in patients with malignant glioma are warranted.

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