GlaxoSmithKline reported data from a Phase II trial of a therapeutic vaccine for patients with non-small cell lung cancer indicating that the drug could prevent the chances of the disease coming back after surgery by a third.

The results come after a string of disappointments with this type of immunotherapeutic approach to cancer in recent years, with high profile failures the likes of CancerVax’s Canvaxin and Merck KGaA/Biomira’s Theratope.

But Vincent Brichard, director of clinical development for the cancer programme at GSK Biologicals in Belgium, told PharmaTimes that the results indicate that, with the selection of the right antibody and use of adjuvants, the approach still has potential.

GSK’s vaccine is targetted against MAGE-A3, a tumor-specific antigen found in 35% to 50% of NSCLC tumours and also seen in a number of other cancer types. It has been formulated alongside a package of proprietary adjuvants, immune-stimulating factors that have been a major focus for GSK as it builds its vaccines business.

The 182-patient Phase II trial, reported at the American Society of Clinical Oncology (ASCO) meeting in Atlanta at the weekend, failed to reach statistical significance despite the 33% reduction in cancer recurrence, but Brichard noted that this was an interim analysis and final results are expected before the end of the year.

The final analysis will focus on time to recurrence as well as disease-free survival, overall survival and lung cancer-related death rate, he noted, and should presage the start of a full Phase III programme in 2007.

Meanwhile, a Phase II trial is underway in malignant melanoma, another cancer with a high proportion (around 74%) of MAGE-A3 expression, while GSK has vaccines targetted against the P501 antigen for prostate cancer in Phase I, the breast cancer-associated HER-2 antigen in Phase I/II, and WT1, over-expressed in leukaemia cells – due to start clinical testing early next year.

Brichard noted that GSK has access to a broad array of tumour antigens and anticipates extending its work on antigen specific cancer immunotherapy into other tumour types.

MAGE-A3 was licensed from the Ludwig Institute of Cancer Research. Earlier this week GSK expanded its relationship with the LICR to include a ‘significant number’ of cancer antigens.

Earlier this year, a report from Datamonitor predicted that despite recent failure, the therapeutic cancer vaccine segment is likely to take off with 12 products in Phase II/III testing, although it still predicted sales of just $500 million for these products in 2010.

Most of these avoid the personalised approach taken by their predecessors and are based on ‘off-the-shelf’ technologies that should bypass issues such as high cost, low scaleability of manufacture, logistical complications and complex regulatory processes, it said.