Target: Skin and lung cancers
GlaxoSmithKline's immunotherapeutics team is betting it has found a mixture of proteins that can boost the body's natural ability to battle several kinds of cancers, all of which express the MAGE-A3 antigen. This protein is expressed on certain tumor cells but not normal cells. The therapy also contains a mix of chemicals, AS15, that together act as an "adjuvant" to enhance the body's immune response to the selected antigen.
GSK is in the midst of Phase III trials testing its vaccine candidate against metastatic melanoma (DERMA study) and non-small cell lung cancer (MAGRIT study). Clinical design details of the studies that will ultimately involve thousands of patients were reported at the 2011 meeting of ASCO (American Society of Clinical Oncology).
If trials against these cancers succeed, GSK will almost certainly try to develop the vaccine against bladder and liver cancers that also commonly express MAGE-A3. Recognizing that only cancers expressing the antigen in quantity are likely to succumb to the new treatment, GSK has been collaborating since 2009 with diagnostics developer Abbott Molecular, to create PCR-based "companion diagnostic" tests that will verify whether or not patients with melanoma and NSCLC qualify for treatment.