Browsing Medical Oncology by Subjects
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Clinical and immunological responses in metastatic melanoma patients vaccinated with a high-dose poly-epitope vaccine.BACKGROUND: Safety and cellular immunogenicity of rising doses and varying regimens of a poly-epitope vaccine were evaluated in advanced metastatic melanoma. The vaccine comprised plasmid DNA and recombinant modified vaccinia virus Ankara (MVA) both expressing a string (Mel3) of seven HLA.A2/A1 epitopes from five melanoma antigens. METHODS: Forty-one HLA-A2 positive patients with stage III/IV melanoma were enrolled. Patient groups received one or two doses of DNA.Mel3 followed by escalating doses of MVA.Mel3. Immunisations then continued eight weekly in the absence of disease progression. Epitope-specific CD8+ T cell responses were evaluated using ex-vivo tetramer and IFN-gamma ELISPOT assays. Safety and clinical responses were monitored. RESULTS: Prime-boost DNA/MVA induced Melan-A-specific CD8+ T cell responses in 22/31 (71%) patients detected by tetramer assay. ELISPOT detected a response to at least one epitope in 10/31 (32%) patients. T cell responder rates were <50% with low-dose DNA/MVA, or MVA alone, rising to 91% with high-dose DNA/MVA. Among eight patients showing evidence of clinical benefit-one PR (24 months+), five SD (5 months+) and two mixed responses-seven had associated immune responses. Melan-A-tetramer+ immunity was associated with a median 8-week increase in time-to-progression (P = 0.037) and 71 week increase in survival (P = 0.0002) compared to non-immunity. High-dose vaccine was well tolerated. The only significant toxicities were flu-like symptoms and injection-site reactions. CONCLUSIONS: DNA.Mel3 and MVA.Mel3 in a prime-boost protocol generated high rates of immune response to melanoma antigen epitopes. The treatment was well tolerated and the correlation of immune responses with patient outcomes encourages further investigation.
Vaccines for the treatment of non-small cell lung cancer: investigational approaches and clinical experience.Globally, lung cancer remains the most common malignancy and the leading cause of cancer-related death. Whilst resection is a therapeutic option for patients with early stage non-small cell lung cancer (NSCLC), most patients have locally advanced or metastatic disease at diagnosis, the treatment of which still presents a considerable challenge for medical oncologists. Therapeutic cancer vaccines offer a novel approach for the treatment of patients with NSCLC in both the adjuvant and advanced disease settings. Although early attempts to use such technologies were of limited success, increased knowledge of the molecular pathology of tumors, of the immune system in general, and of tumor immunity in particular, has facilitated the production of more sophisticated anticancer vaccines. A number of promising vaccine candidates based on different types of antigenic stimulus have now been evaluated in clinical studies. These include belagenpumatucel-L, a vaccine derived from four genetically modified, irradiated NSCLC cell lines and target protein-specific vaccines designed to induce responses against epidermal growth factor (EGF), melanoma-associated antigen A3 (MAGE-A3) and mucin 1 (MUC1). The purpose of this review is to describe the mode of action of the vaccine candidates that are most advanced in their clinical development for the treatment of NSCLC, and to summarize the most recent data from clinical studies of these vaccines.