title: A multivalent bcr-abl fusion peptide vaccination trial in patients with chronic myeloid leukemia.
abstract: A tumor-specific, bcr-abl-derived fusion peptide vaccine can be safely administered to patients with chronic myelogenous leukemia (CML) and can elicit a bcr-abl peptide-specific T-cell immune response. In the present phase 2 trial, 14 patients with CML in chronic phase were vaccinated with 6 fusion peptides mixed with Quillaja saponaria (QS-21). No significant toxic effects were observed. In 14 of 14 patients, delayed-type hypersensitivity (DTH) and/or CD4 proliferative responses developed after beginning vaccinations, and 11 of 14 patients showed interferon-gamma (IFN-gamma) release by CD4 enzyme-linked immunospot (ELISPOT) at one or more time points. These responses were CD4(+)CD45RO(+). A peptide-specific CD8(+) interferon-gamma ELISPOT was found in 4 patients. Four patients in hematologic remission had a decrease in Philadelphia chromosome (Ph) percentage (3 concurrently receiving interferon-alpha and 1 on imatinib mesylate), and 3 patients in molecular relapse after allogenic transplantation became transiently polymerase chain reaction (PCR) negative after vaccination; 2 of these patients received concurrent donor lymphocyte infusion (DLI). All 5 patients on IFN-alpha ultimately reached a complete cytogenetic remission. In conclusion, a tumor-specific bcr-abl breakpoint peptide-derived vaccine can be safely administered and can reliably elicit measurable peptide-specific CD4 immune responses, including in patients after bone marrow transplantation, on interferon, or on imatinib mesylate. A relationship between the clinical responses and vaccination cannot be determined from this trial.
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000009:adverse effects / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000276:immunology*; D006801:Humans; D006968:Hypersensitivity, Delayed; D007371:Interferon-gamma / Q000096:biosynthesis; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000276:immunology* / Q000628:therapy*; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D012449:Safety; D022223:Vaccines, Subunit / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D019496:Cancer Vaccines; D022223:Vaccines, Subunit; D007371:Interferon-gamma; D016044:Fusion Proteins, bcr-abl