Active Specific Immunotherapy Phase III Trials for Malignant Melanoma: Systematic Analysis and Critical Appraisal

What's new in skin cancer? An analysis of guidelines and systematic reviews published in 2008-2009

This review summarizes clinically important findings from 17 systematic reviews and 2 guidelines on skin cancer indexed between April 2008 and April 2009. Melanoma primary-prevention measures, such as education, are more likely to be successful in younger children than adolescents, and general population screening for melanoma by whole-body examination is not currently supported by the evidence. A large systematic review of melanoma and pregnancy concluded that pregnancy does not affect prognosis. Two systematic reviews imply that sunburn later in life also increases the risk of melanoma, and that it is just as important as sunburn early in life. Three systematic reviews discussed the role of positron emission tomography and sentinel lymph-node biopsy for melanoma staging, but produced conflicting results. Superior diagnostic accuracy of dermatoscopy over naked-eye examination for melanoma was found in one review, while a second implied nonsignificantly higher sensitivity of computer-based diagnostic methods over dermatoscopy for melanoma but with reduced specificity. There were no identified randomized controlled trials of treatments for unresectable recurrent melanoma, and a review of immunotherapy with vaccines for melanoma failed to prove improved overall and disease-free survival. Guidelines for the management of basal cell carcinoma call for risk stratification, based on numerous factors including tumour size, site and histological subtype. Squamous cell carcinoma of the ear has been shown to spread to regional lymph nodes more commonly than to other sites, and may be predicted by depth of invasion, tumour size, cellular differentiation and completeness of excision.

Establishment of stable cell lines for personalized melanoma cell vaccine

Personalized vaccine, recognized after the failure of allogenic melanoma whole cell and lysate vaccine phase III trials, involves culturing cells from a patient's own tumor within a short duration and with less passages but with optimized expression of tumor-associated antigens (TAAs). Its feasibility is established by comparing pure cell lines generated from fresh and cryopreserved tissues (n=164) of patients with lymph node (LN) and distant metastases. Stable cell lines (from 67% of specimens) are subcultured after cryopreserving them. Pure cell lines established after eliminating fibroblasts (from 96% of the cell lines) include those from LN (69%), soft tissues including cutaneous (60%), liver (64%), lung (75%), bone (80%), brain (75%), and other sites (73%). Within 3.5 months, stable cell lines (> or =50 million cells) are established from initiating the cell culture. For LN metastases, the duration differs significantly (P2<0.05) between fresh (1.4-3.4 months) and cryopreserved (2.4-4.7 months) tissues. The expression of TAAs varies as follows: Tyrosinase (81%) >Melan-A (80%) >HMB45/gp-100 (75%) >Mel-5/TRP-1 (65%) >MAGE-1 (47%) > S-100 (28%). The number of TAAs per cell line differs between early (<7) and late (>7) passages. Among late passage cell lines, lesser percentage of cell lines express three to six antigens pointing out that early passage (<7) cell lines may be needed for antigen-targeted immunotherapy. This study provides a protocol for establishing cell lines within 2-5 months for personalized vaccine therapy for nodal and organ metastatic melanoma patients.

Improvement of a dendritic cell-based tumour vaccine by an influenza virus

BACKGROUND

Induction of cytotoxic T cells by dendritic cells (DCs) is a promising approach to tumour-immunotherapy. A standardized effective preparation of DCs remains a challenge for clinical application.

MATERIAL AND METHODS

We assessed whether influenza A partial NS1 deletion (NS1-124) - or complete NS1 deletion (delNS1) vaccine viruses can be employed to enhance monocyte-derived dendritic cell (MODC)-based T-cell stimulation directed against malignant cells in vitro.

RESULTS

Infection of cultures containing human MODCs and CD3(+) T cells with NS1 deletion viruses led to an increased induction of type I interferons and IL-6 compared with infection with wild-type virus. This correlated with the fact that infection of MODCs with NS1 deletion viruses but not with wild type virus led to stimulation of a cytotoxic T-cell (CTL) response against the Panc-1 cells, which were used as cell lysate to prime the MODCs. Moreover, stimulation of MODCs with Panc-1 tumour cell lysate obtained via lysis with the complete deletion virus delNS1, but not with the partial NS1 deletion virus also enhanced the CTL response against the tumour cells. Induction of function CTL response in those assays correlated with an increased proliferation of CD8(+) T cells.

CONCLUSIONS

The pro-inflammatory capacity of influenza NS1 deletion vaccine viruses could serve as an adjuvant-like agent to improve preparations of MODC-based anti-cancer vaccines. The complete NS1 deletion virus appears to be more potent as adjuvant when used for production of tumour lysates.

Treatment combinations targeting apoptosis to improve immunotherapy of melanoma

Immunotherapy based on T cell responses to the tumor is believed to involve killing of cancer cells by induction of apoptosis. The predominant mechanisms are death ligand-induced signaling mainly by TNF-related apoptosis-inducing ligand (TRAIL) mediated by CD4 T cells, monocytes and dendritic cells, and perforin/granzyme mediated apoptosis mediated by CD8 T cells and NK cells. Resistance against TRAIL involves loss of TRAIL death receptors and/or activation of the MEK and/or Akt signal pathways. Resistance to CD8 CTL responses also involves activation of the MEK and/or Akt pathways. Apoptosis induced by immune responses is regulated by the Bcl-2 family of proteins. Many reagents have been developed against the Bcl-2 antiapoptotic proteins and clinical trials combining them with immunotherapy are awaited. The second group of agents that regulate the Bcl-2 family of proteins are the signal pathway inhibitors. Clinical trials with inhibitors of RAS, RAF or MEK are in progress and would appear an exciting combination with immunotherapy. One of the main drivers of resistance to apoptosis are adaptive mechanisms that allow cancer cells to overcome endoplasmic reticulum (ER) stress. These adaptive mechanisms inhibit practically all known apoptotic pathways and create an acidic environment that may reduce infiltration of lymphocytes against the tumor. The signal pathway inhibitors may be effective against these adaptive processes but additional agents that target ER stress pathways are in development. In conclusion, combination of immunotherapy with agents that target antiapoptotic mechanisms in cancer cells offers a new approach that requires evaluation in clinical trials.