UNSW and University of Queensland researchers have teamed with Prima BioMed Ltd to develop an oral vaccine for the prevention of cervical cancer. The development of an oral vaccine could reduce the incidence of cervical cancer, which claims more than 253,000 lives globally each year.

Nearly all cases of cervical cancer are caused by infection with the human papillomavirus (HPV), which is typically transmitted through sexual contact. Injectable vaccines – such as Gardasil and Cervarix – that guard against high-risk strains of HPV have been on the market since 2006. They are targeted at girls and women aged nine to 26 because the vaccine is effective only before HPV-infection.

The availability of an orally-delivered vaccine would overcome several barriers to injectable vaccines, including their expense, requirements for repeated doses and sterile conditions, and patient fear and pain, which lead to poor patient compliance and compromised therapeutic effects.

A vaccine in tablet form would also lessen the risk of infection among patients and healthcare workers that is associated with mass parenteral vaccinations. In the US alone, more than one million people suffer injury or infection from needles annually, which can often require costly treatment.

The three-year research program is a collaboration between the Australian biotechnology company Prima BioMed Ltd, the Diamantina Institute for Cancer at the University of Queensland under the leadership of Professor Ian Frazer, who was the developer of the Gardasil vaccine, and Professor Neil Foster and his team at UNSW’s Supercritical Fluids Group. The alliance will unite medical practitioners, immunologists, material scientists, pharmacists and chemical engineers on a project of international significance.

“This joint research program may have significant benefit for mass vaccination environments,” says UNSW Professor Neil Foster, “especially in developing countries where the amelioration of production costs and requirements for specialized health workers and hygiene standards are decisive factors. In this regard oral vaccination can be a significant contributor to public health by enabling life saving interventions on a large scale.”

The key challenge of the research program is to encapsulate the vaccine so that it can safely pass through the body and be released to a target site in the body. This work will draw on the expertise of UNSW’s Supercritical Fluids Group, which is a world leader in the use of nanotechnology and dense gas technology to orally deliver drugs and other bio-active compounds, as well as via the pulmonary route.

Despite the potential advantages of oral vaccines, there are few oral vaccines licensed for human use. Oral vaccines currently available include polio, rotavirus, adenovirus, smallpox, rabies, influenza, typhoid and cholera. There are several reasons for the lack of a generic technology for oral vaccine delivery. These include:

• harsh conditions in the gastrointestinal tract may degrade vaccines;
• orally-administered vaccines must be absorbed and presented to
appropriate cells of the immune system. The usual inefficiency of this process requires the administration of large vaccine doses; and,
• the potential for enzymatic degradation, leading to a short vaccine
half-life. A major challenge is to greatly improve oral vaccine absorption from the usual 1 percent.

Another challenge to vaccine development has been economic: many of the diseases most demanding a vaccine, including malaria, HIV ad tuberculosis, exist principally in poorer nations.

Pharmaceutical firms and biotechnology companies have therefore had little incentive to develop vaccines for these diseases because there is little revenue potential. Even in more affluent countries, financial returns are usually minimal.

However the global vaccine market forecast to 2012 reports that vaccines, have emerged as one of the most lucrative segments of the pharmaceutical industry. The industry now has a projected compound annual growth rate of over 16 percent in the next 5 years.

Further, the cancer vaccine market, led by cervical cancer vaccines such as Gardasil, is presently one of the most lucrative areas for vaccine manufacturers. Overall cancer vaccines are expected to account for nearly 27 percent of the total vaccine revenues by 2012. The global vaccine market is expected to register revenues in excess of US$30 billion by 2012.

Commenting on the announcement, Prima BioMed executive director Martin Rogers said: “A fully developed oral drug delivery platform would provide significant benefits to patients in the form of reduced side-effects, more efficient utilisation of dosages and improved patient compliance. We look forward to commencing work on this exciting product development with Professors Ian Frazer and Neil Foster, and their respective teams”.

Media contact
Dan Gaffney, UNSW Media, 0411 156 015