13 October 2005 Cervical Cancer On The Ropes, Ovarian Cancer Next? by Angie Rankman
With the final stage clinical trials over, women all over the globe will be happy to know that a cervical cancer vaccine with a 100 percent success rate will be available by early 2006. This is a great achievement by the vaccine’s Australian researchers, as cervical cancer is the second most common cancer in women. More than 500,000 cases are diagnosed annually and it kills an estimated 275,000 women around the world every year. Astonishingly, the human papilloma virus (HPV) that causes cervical cancer is contracted by up to an estimated 70 percent of sexually active women.
Developed by pioneering University of Queensland (UQ) researcher Professor Ian Frazer and his team, the final results of the trials were announced in New York by the vaccine’s developers, Merck & Co. “It is very encouraging to see such great results coming out of Australian research,” exclaimed Frazer. “It is very rare, almost unheard of, to achieve a 100 percent efficacy rate in any treatment, so these results are truly wonderful,” he added. Known as Gardasil™, the product should be available from early 2006, once it gains FDA approval.
Gardasil™ works by preventing the development of pre-cancerous and non-invasive HPVs, which makes the vaccine preventative rather than curative. While cervical cancer is directly caused by this viral infection, many other cancers are not. Professor Frazer acknowledges this limitation and is currently working on a new vaccine that will treat already developed cancers. “My major focus these days, as indeed it was right back in the beginning, is on developing a vaccine to treat these existing infections,” he said. “We have produced a second vaccine which we hope will do this, however clinical trials are still at a very early stage. A therapeutic vaccine to treat already infected individuals is much harder to develop than a vaccine to prevent infection.”
This could serve to ground the expectations that women may have about cures to non-viral cancers. The difference between a non-viral cancer vaccine and a viral vaccine becomes clearer when we consider other streams of research focusing on cancers in women.
As it happens, yet another Australian company, Prima BioMed, has developed a cancer vaccine, this time for ovarian cancer. The researchers, based in Melbourne, announced that they had completed the initial recruitment for a Phase IIa clinical trial. Analysis of those patients already receiving treatment is already underway, and these results are scheduled for release in December.
Ovarian cancer is trickier to deal with, as a normally functioning immune system does not detect ovarian cancer cells because they invade the body by stealth; they ostensibly “camouflage” themselves so as to appear like the body’s own cells. Consequently, the science behind Prima’s ovarian vaccine is different to that of the cervical cancer treatment. If all goes well, the ovarian cancer vaccine will significantly boost and, hopefully, re-educate the body’s immune system to recognize cancer cells as intruders. As revolutionary as this sounds, you can appreciate that the methodology and experimentation for such a treatment is quite different to that of other forms of cancer vaccines. It seems that not all cancers are created equal, but then the human body is a complex system.
Encouragingly, the companies involved in the HPV cervical cancer vaccine have made a commitment to differential pricing that will enhance availability of the drug in the developing world. And that’s good news, because it means women in developing nations will now have one less life threatening infection to worry about.
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