The vaccine showed exceptional and significant efficacy in preclinical trials as both a preventative vaccine and as an anti-tumour therapy against HER-2 expressing tumours and could provide a boost to the prognosis of many breast cancer sufferers.
The cancer vaccine sector took a huge blow when the leading candidates, Biomira's breast cancer vaccine Theratope and CancerVax / Serono's skin cancer vaccine Canvaxin both failed in late stage clinical trials and all work on them has since ceased.
In spite of these high-profile failures a recent Datamonitor report, Therapeutic Cancer Vaccines - A turbulent path from bench to bedside, states that there are 14 cancer vaccines in late stage development that may have a combined worldwide sales potential as high as $3.1bn (€2.4bn) by 2015. The long wait for the first cancer vaccine to reach the market may soon be over if the US Food and Drug Administration (FDA) licenses Dendreon's prostate cancer vaccine Provenge (sipuleucel-T).
MVA-BN-HER2 targets the HER-2 enzyme, that controls how cells grow, divide and repair themselves, which is over-expressed in 20 to 40 per cent of breast cancers. The overexpression of this gene causes the production of HER-2 receptors and is associated with a poor prognosis due to increased cancer recurrence.
Preclinical trials showed that the MVA-BN-HER2 antibody almost completely eradicated highly aggressive tumours in a lung metastasis model within 14 days by inducing an extremely rapid antigen-specific immune response.
If it reaches the market, MVA-BN-HER2 would address a market dominated by Roche and Genentech's blockbuster monoclonal antibody Herceptin (trastuzumab) that also targets HER-2 receptors. The drug had combined worldwide sales of CHF 2.8bn (€1.7bn) in the first nine months of 2006.
The studies will evaluate the safety and tolerability of the new antibody as well as the biological activity by measuring immune responses in patients. The studies will not only test the drug as a first line therapy of metastatic breast cancer, but also as a combination treatment with Herceptin and various chemotherapies.
Other breast HER-2 cancer vaccine candidates in development include Apthera / the US Army's E75, soon to enter Phase III trials, and Generex subsidiary Antigen Express' AE75, soon to enter Phase II.
Meanwhile, Oxford BioMedica has just announced that its TroVax renal cancer vaccine will enter Phase III trials at the UK National Cancer Research Network (NCRN). TroVax is in Phase II testing for breast cancer.