Olivier Gruselle

Predictive Gene Signature in MAGE-A3 Antigen-Specific Cancer Immunotherapy

PURPOSE To detect a pretreatment gene expression signature (GS) predictive of response to MAGE-A3 immunotherapeutic in patients with metastatic melanoma and to investigate its applicability in a different cancer setting (adjuvant therapy of resected early-stage non-small-cell lung cancer [NSCLC]). PATIENTS AND METHODS Patients were participants in two phase II studies of the recombinant MAGE-A3 antigen combined with an immunostimulant (AS15 or AS02B). mRNA from melanoma biopsies was analyzed by microarray analysis and quantitative polymerase chain reaction. These results were used to identify and cross-validate the GS, which was then applied to the NSCLC data. RESULTS In the patients with melanoma, 84 genes were identified whose expression was potentially associated with clinical benefit. This effect was strongest when the immunostimulant AS15 was included in the immunotherapy (hazard ratio [HR] for overall survival, 0.37; 95% CI, 0.13 to 1.05; P = .06) and was less strong with the other immunostimulant AS02B (HR, 0.84; 95% CI, 0.36 to 1.97; P = .70). The same GS was then used to predict the outcome for patients with resected NSCLC treated with MAGE-A3 plus AS02B; actively treated GS-positive patients showed a favorable disease-free interval compared with placebo-treated GS-positive patients (HR, 0.42; 95% CI, 0.17 to 1.03; P = .06), whereas among GS-negative patients, no such difference was found (HR, 1.17; 95% CI, 0.59 to 2.31; P = .65). The genes identified were mainly immune related, involving interferon gamma pathways and specific chemokines, suggesting that their pretreatment expression influences the tumors immune microenvironment and the patients clinical response. CONCLUSION An 84-gene GS associated with clinical response for MAGE-A3 immunotherapeutic was identified in metastatic melanoma and confirmed in resected NSCLC.

Gene expression of MAGE-A3 and PRAME tumor antigens and EGFR mutational status in Taiwanese non–small cell lung cancer patients

To determine the frequency of expression of the tumor‐associated antigens (TAAs) melanoma‐associated antigen A3 (MAGE‐A3) and preferentially expressed antigen of melanoma (PRAME) and the rate of EGFR mutations in a Taiwanese non–small cell lung cancer (NSCLC) population including only adenocarcinomas and squamous cell carcinomas. Furthermore, to investigate associations between TAA expression and EGFR mutations and to evaluate these TAAs as prognostic markers for overall survival. The occurrence of single nucleotide polymorphisms in MAGEA3 and PRAME was also assessed.

The prevalence of expression of MAGE-A3 and PRAME tumor antigens in East and South East Asian non-small cell lung cancer patients

INTRODUCTION Treatment of non-small cell lung cancer (NSCLC) is an important and often unmet medical need regardless of the disease stage at the time of first diagnosis. Antigen-specific immunotherapy may be a feasible therapeutic option if tumor associated antigens (TAAs) that can be targeted by the patients immune system are identified. The study objective (NCT01837511) was to investigate the expression rates of MAGE-A3 and PRAME in tumors from East Asian NSCLC patients, and the associations between TAA expression and clinico-pathologic patient characteristics. METHODS Archived formalin-fixed paraffin-embedded tumor tissue specimens were tested for MAGE-A3 and PRAME expression by quantitative reverse transcription polymerase chain reaction. Exploratory analyses of the impact of patient and tumor characteristics on antigen expression were performed by multivariate logistic regression analyses. RESULTS A total of 377 specimens were tested and a valid expression result was obtained for 86.5% and 92.6% for MAGE-A3 and PRAME, respectively. Of the specimens with valid test results, 26.4% expressed MAGE-A3, 49.9% PRAME, 20.0% both and 57.5% expressed at least one TAA. The same pattern of associations between antigen expression and patient and tumor characteristics was found for both TAAs: higher rates of antigen-positive tumors were found in squamous cell carcinomas compared to adenocarcinomas, and for smokers compared to non-smokers. CONCLUSIONS Expression of MAGE-A3 and PRAME suggests an association with tumor histology and the patients smoking status. The rates of TAA-positive tumors found in these East and South East Asian NSCLC patients indicate that both antigens may serve as targets for antigen-specific immunotherapies.

Abstract A37: Identification of a gene expression signature predictive of clinical activity following MAGE‐A3 ASCI treatment

Clinical data today highlight the encouraging potential of the MAGE‐A3 Antigen‐Specific Cancer Immunotherapeutic (ASCI) for cancer treatment. The MAGE‐A3 gene encodes a tumor‐specific antigen expressed on tumor cells only. When used as a recombinant protein and combined with an immunological Adjuvant System designed to enhance the immune response to the MAGE‐A3 antigen, it was shown to induce specific T‐cell responses and long‐lasting clinical objective responses in metastatic melanoma (Phase II NCT00086866 trial) (Kruit et al. JCO 2008 26:9065), and demonstrated proof‐of‐concept in Non‐Small Cell Lung Cancer (NSCLC; Phase II NCT00290355 trial) (Vansteenkiste et al. JCO 2007 25:7554). In these 2 trials, gene expression profiling by microarrays was used to identify biomarkers predictive of the clinical activity of the MAGE‐A3 ASCI. A first analysis carried out on samples from melanoma patients using supervised hierarchical clustering of 2 objective responders and 2 non‐responders identified 2 gene clusters based on differential gene expression. This immune gene expression signature was then confirmed in an analysis of 22‐patient samples, and independently validated on an additional 30‐patient testing set; furthermore these analyses confirmed the association of clinical benefit and the molecular signature. Most of the identified genes are immune‐related, defining a particular biological context present in the tumor environment before immunization. This was confirmed by selecting genes using all patients eligible for gene expression profiling. Upon crossvalidation, median overall survival was improved significantly in the population of patients whose tumor presented the gene signature (GS): 28 months in the GS+ population, 16.2 months in the GS−. The predictive value of the melanoma signature was tested in NSCLC. A subset of 49 genes discovered in the melanoma Phase II trial was assayed by qPCR on biopsies taken prior to any ASCI treatment from 137 patients of the lung Phase II trial. Applied to NSCLC patients, this biomarker showed that the relative reduction in the risk of recurrence upon MAGE‐A3 ASCI treatment is increased by about 2 fold in the patients with the predictive gene signature as compared to the overall population: from 25% relative improvement in the overall population to 53% in patients whose tumor presents the predictive gene signature. In conclusion, two clinical proof‐of‐concepts have been obtained with the MAGE‐A3 ASCI in 2 different types of tumors, NSCLC and melanoma. More importantly, we have identified a gene expression signature predictive of clinical activity of the MAGE‐A3 ASCI treatment. The initiation of Phase III studies in NSCLC (MAGRIT) and melanoma (DERMA) is a unique opportunity to validate prospectively these biomarkers with the ultimate goal to select patients that are the most likely to benefit from the MAGE‐A3 ASCI therapy. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A37.