Immunoreactivity to WT1 peptide vaccine is associated with prognosis in elderly patients with acute myeloid leukemia: follow-up study of randomized phase II trial of OCV-501, an HLA class II-binding WT1 polypeptide

• DOI: 10.1007/s00262-023-03432-4
• Publication Date: 2023-04-24T12:03:25Z
• Authors: Tomoki Naoe; Akiko Saito; Nahoko Hosono; Senji Kasahara; Hideharu Muto; Kaoru Hatano; Mizuki Ogura; Taro Masunari; Masatsugu Tanaka; Kensuke Usuki; Yuichi Ishikawa; Koji Ando; Yukio Kondo; Yusuke Takagi; Satoru Takada; Maho Ishikawa; Ilseung Choi; Akihiro Sano; Hirokazu Nagai
• Keywords: Leukemia, Myeloid, Acute; Brief Report; Immunoglobulin G; Vaccines, Subunit; Humans; WT1 Proteins; Prognosis; 3. Good health; Aged; Follow-Up Studies

AbstractWe previously conducted a randomized phase II trial of OCV-501, a WT1 peptide presented by helper T cells, in elderly AML (acute myeloid leukemia) patients in first remission, indicating no difference in 2-year disease-free survival (DSF) between the OCV-501 and placebo groups. Here, we analyzed 5-year outcome and biomarkers. Five-year DFS was 36.0% in the OCV-501 group (N = 52) and 33.7% in the placebo group (N = 53), with no significant difference (p = 0.74). The peripheral WT1 mRNA levels were marginally suppressed in the OCV-501 group compared with the placebo group. Enhanced anti-OCV-501 IgG response by the 25th week was an independent favorable prognostic factor. Anti-OCV-501 IFNγ responses were less frequent than the IgG reactions. These findings suggest that host immunoreactivity has a significant impact on the prognosis of AML and that further improvement of the WT1 peptide vaccine is needed.