Defining the critical hurdles in cancer immunotherapy.

Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer.

Dendritic cells pulsed with HER-2/neu-derived peptides can induce specific T-cell responses in patients with gastric cancer.

PURPOSE: We have previously reported (K. Kono et al., Int. J. Cancer, 78: 202-208, 1998) that HER-2/neu-derived peptides are naturally processed as tumor-associated antigens recognized by tumor-specific, human leukocyte antigen (HLA)-A2-restricted CTLs in gastric cancer. In the present study, we described a Phase-1 vaccination trial in gastric cancer patients using dendritic cells (DCs) pulsed with the immunodominant HER-2/neu(p369) peptides. EXPERIMENTAL DESIGN: Nine enrolled patients, who had HER-2/neu-overexpressing tumors and who were HLA-A2 positive, received four vaccinations by DCs pulsed with HER-2(p369) peptide at 2-week intervals intradermally. RESULTS: There were no serious adverse effects noted in the immunized patients. Peripheral blood mononuclear cells, preimmunization and after the fourth immunization, were cultured with autologous, HER-2(p369)-pulsed antigen-presenting cells for 12 days. Thereafter, peptide specificity was evaluated by IFN-gamma secretion assay from cultured T cells against T2 cells pulsed with HER-2(p369) peptide. HER-2/neu peptide-specific recognition could be demonstrated in six of nine patients after immunization, whereas there was no HER-2/neu peptide-specific recognition before immunization. The peptide-specific CTL lines isolated from two of the patients could also lyse a HER2/neu-transfected cell line. Furthermore, a peptide-specific delayed-type hypersensitivity response occurred in three of nine patients. One of the patients underwent a partial clinical response concurrent with a decrease of tumor marker. Another patient demonstrated a stabilization of disease status for a period of 3 months. CONCLUSIONS: Taken together, tumor vaccination therapy with DCs pulsed with HER-2/neu-peptides may be a potential candidate for the novel treatment of gastric cancer patients.