New data presented by GlaxoSmithKline (GSK) highlighted the potential of its investigational MAGE-A3 Antigen-Specific Cancer Immunotherapeutic (ASCI) through results of three studies evaluating highly targeted immunotherapy as a treatment for metastatic melanoma and non-small cell lung cancer (NSCLC).

These data were presented at the 2008 American Society of Clinical Oncology (ASCO) annual meeting in Chicago.

A randomised, open label phase II study designed to evaluate two different formulations of the MAGE-A3 ASCI in patients with metastatic melanoma has been conducted. In this study, the ASCI, which is a combination of MAGE-A3 recombinant protein and a GSK proprietary adjuvant system, was evaluated and resultant data suggest a positive trend for clinical response. These data also demonstrate the induction of a desirable immune response, including humoral and cellular responsesi.

These study results represent a second positive trend for clinical activity for the novel MAGE-A3 cancer immunotherapeutic, following encouraging clinical results reported in a separate double-blind, placebo-controlled phase II study of patients with NSCLC. The encouraging results from the phase II NSCLC study have led to a phase III safety and efficacy trial in MAGE-A3-positive NSCLC patients (stage IB, II and IIIA) who have undergone complete surgical resection.

At this year's ASCO, GSK also presented data regarding the use of the genetic profiling of melanoma in predicting clinical outcomes of treatment with MAGE-A3 ASCI. Biopsies performed on the melanoma tumours prior to immunisation were used to identify genetic markers expressed by the disease. These markers enabled researchers to establish a correlation between the expression of given genes and the clinical response induced by the MAGE-A3 ASCI in metastatic melanoma.

In addition, GSK presented data on the genetic profiling of patients with NSCLC. In a retrospective analysis, a predictive gene signature similar to that observed in melanoma was associated with a lower rate of disease recurrence in the MAGE-A3 treated group.

"These phase II data mark another significant milestone for the development of the MAGE-A3 ASCI as a potential novel cancer therapy. Validation of a predictive gene signature, combined with selection of patients who express cancer antigens of interest, may allow GSK to improve predictions of a patient's clinical response to treatment with cancer immunotherapeutics," said Johan Vansteenkiste, Professor of Internal Medicine, Faculty of Medicine, Catholic University of Leuven, Belgium. "They also provide further positive proof-of-concept phase II data which highlight the importance of the ongoing MAGRIT phase III trial in Non-Small Cell Lung Cancer".