A randomized pilot trial testing the safety and immunologic effects of a MAGE-A3 protein plus AS15 immunostimulant administered into muscle or into dermal/subcutaneous sites

Abstract

Introduction Methods to induce T cell responses to protein vaccines have not been optimized. The immunostimulant AS15 has been administered with the recombinant MAGE-A3 protein (recMAGE-A3) i.m. but not i.d. or s.c. This study tests hypotheses that the i.d./s.c. route is safe and will increase CD4+ and CD8+ T cell responses to MAGE-A3. Patients and 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 IFNγ ELISPOT assay and by flow cytometry for multifunctional (TNFα/IFNγ) 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 1 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. 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.

Intratumoral interferon-gamma increases chemokine production but fails to increase T cell infiltration of human melanoma metastases

“…If the maximum of the 2 negative controls for a given sample was zero, a meaningful fold-increase could not be calculated; in those cases, the minimum detectable value for the assay was used as the negative control for that sample to enable defining a T-cell response. These criteria match those we used previously [20,21]. Interassay coefficients of variation (CVs) were calculated for normal donor PBMC responses to a pool of 32 peptides from CMV, Epstein-Barr virus and influenza proteins (CEF peptides) [22].…”

Topical treatment of melanoma metastases with imiquimod, plus administration of a cancer vaccine, promotes immune signatures in the metastases

“…Briefly, assays were conducted on PBMCs directly ex vivo after cryopreservation. A patient was considered to have a response to vaccination (yes/no) if the following criteria were met: the ratio of T-cell response to the pooled 12MP peptides relative to T-cell response to the maximum of the negative controls was greater than 2, and the spots counted for the pooled experimental peptides was at least 20 (per 10 5 CD8 + cells) greater than the number of spots for the negative control (24). If the maximum of the negative controls for a given sample was zero, a meaningful fold-increase could not be calculated; in those cases, the minimum detectable value among all similar assays was used as the negative control for that sample to enable defining a T-cell response.…”

Trial watch: Peptide-based vaccines in anticancer therapy

“…Peptide-based vaccination was employed as a standalone adjuvanted intervention, 140-146 or combined with chemotherapy 147-149 radiation therapy 147,150 or other forms of treatment including other immunotherapies. 148,149,151-158 These studies enrolled patients with hematological malignancies, 151,159 brain tumors, 152,153 non-small cell lung carcinoma (NSCLC), 140,147,160 breast cancer, 141,148,161 , prostate carcinoma, 142,154 melanoma, 144-146,155-158,162 . ovarian cancer.…”

“…149 , cervical cancer, 163 hepatocellular carcinoma 164 and biliary tract cancer 165 . The TAAs harnessed for the construction of peptide-based vaccines in these studies included the cancer/testis antigen 1B (CTAG1B; best known as NY-ESO-1), 144 MAGE family member A3 (MAGEA3), 140,146,147 TTK protein kinase (TTK), 158 WT1, 151,166 baculoviral IAP repeat containing 5 (BIRC5; best known as survivin), 149 mutant epidermal growth factor receptor (EGFRvIII), 153 erb-b2 receptor tyrosine kinase 2 (ERBB2; best known as HER2), 148 indoleamine 2,3 dioxygenase 1 (IDO1), 157 TCR gamma alternative reading frame protein (TARP), 154 and multiple glioma-associated antigens. 152 Most often, peptide-based vaccines were well tolerated and no severe side effects were reported.…”

“…Mild side effects were sporadic and included flu-like symptoms, fatigue and minor reactions at the injection site. Immunes responses driven by vaccination were documented in a variety of studies based on (1) interferon gamma (IFNG) production by T cells with enzyme-linked immunospot (ELISPOT) assays, 142,151,152,154,155 (2) tumor infiltration by CD4 + and CD8 + lymphocyte infiltration, 144,145,147,157,158 or (3) presence of peptide-specific antibodies in the serum. 158 Sporadic clinical responses were also documented (see below).…”