Methods
We conducted the current early phase II study of the PPV in children diagnosed with refractory solid cancer. The details of the protocol are given in Supplemental Appendix A1. The patient profiles are presented in Table 1. Four patients with pediatric sarcoma (alveolar rhabdomyosarcoma [ARMS], osteosarcoma, alveolar small cell tumor, and Wilms tumor, respectively) were enrolled in this study between October 2016 and March 2017. The safety profile was assessed by monitoring the occurrence of adverse events according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0). For measuring the IgG responses to 31 peptides, IgG titers specific to the antigen peptides in the plasma were evaluated by using a bead-based multiplex Luminex assay, as previously described.5-12 We adopted “Fluorescence Intensity Unit (FIU)” for measuring peptide-specific IgG response associated with personalized vaccine. Komatsu reported the comparison between the IgG measured by ELISA and FIU12. The total sums of the immunoglobulins specific to each peptide were calculated. The protocol was approved by the Kurume University Ethical Committee and registered in the UMIN Clinical Trials registry (UMIN # 000030249). The patient caregivers were given a full explanation of the protocol and provided informed consent before enrollment.