Conclusion
The MAGE-A3 immunotherapeutic was well tolerated after i.d./s.c. administration, with trends to higher CD4(+) T cell response rates than with i.m. administration. This study supports further study of AS15 by i.d./s.c. administration.
Methods
Twenty-five patients with resected stage IIB-IV MAGE-A3(+) melanoma were randomized to immunization with recMAGE-A3 combined with AS15 immunostimulant (MAGE-A3 immunotherapeutic) either i.m. (group A, n = 13) or i.d./s.c. (group B, n = 12). Adverse events were recorded. Ab responses to MAGE-A3 were measured by ELISA. T cell responses to overlapping MAGE-A3 peptides were assessed in PBMC and a sentinel immunized node (SIN) after 1 in vitro stimulation with recMAGE-A3, by IFN-γ ELISPOT assay and by flow cytometry for multifunctional (TNF-α/IFN-γ) responses.
Results
Both routes of immunization were well tolerated without treatment-related grade 3 adverse events. All patients had durable Ab responses. For all 25 patients, the T cell response rate by ELISPOT assay was 30 % in SIN (7/23) but only 4 % (1/25) in PBMC. By flow cytometry, multifunctional CD8(+) T cell responses were identified in one patient in each group; multifunctional CD4(+) T cell response rates for groups A and B, respectively, were 31 and 64 % in SIN and 31 and 50 % in PBMC.