June 22, 2003 - National Cancer Insitute: RPCV Laura A. Koutsky develops breakthrough vaccine against cervial cancer
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June 22, 2003 - National Cancer Insitute: RPCV Laura A. Koutsky develops breakthrough vaccine against cervial cancer
RPCV Laura A. Koutsky develops breakthrough vaccine against cervial cancer
Read and comment on this excerpt from a story from the National Cancer Insitute on RPCV Dr. Laura A. Koutsky, a professor of epidemiology at the University of Washington in Seattle who together with Dr. Kathrin U. Jansen developed a breakthrough vaccine to protect women against cervical cancer. Read the story at:
The Cross-Country Duo Behind a Breakthrough Vaccine*
* This link was active on the date it was posted. PCOL is not responsible for broken links which may have changed.
The Cross-Country Duo Behind a Breakthrough Vaccine
By DENISE GRADY
ine years ago, when Dr. Kathrin U. Jansen began trying to create a vaccine to protect women against cervical cancer, other scientists gave her about a 10 percent chance of success. Some of her own colleagues at Merck Research Laboratories shook their heads. Even a job applicant whom she interviewed took it upon himself to tell her that her idea would never work. (He did not get the job.) At conferences where she talked about the project, she felt waves of skepticism from the audience.
"That gives you even more energy," Dr. Jansen said.
It also makes victory all the more sweet. Last year, she and her research team created the first vaccine to work against cervical cancer. In a large study, it proved 100 percent effective against a common virus that causes half of all cases of the disease. The results were published in November in The New England Journal of Medicine, with an enthusiastic editorial titled, "The Beginning of the End of Cervical Cancer?" by a Harvard scientist who was not involved in the study.
A successful vaccine could sharply reduce the rates of the cancer, which is a major cause of sickness and death among women worldwide. Globally, there are 470,000 new cases a year, and 225,000 women die from the disease. Most of the deaths occur in developing countries where women do not have regular Pap tests, which can detect cancers or precancers early enough to cure them. Vaccination is easier than cancer screening, and may be a better option in many parts of the world.
"For individuals in countries with no screening, a vaccine is a lifesaver," said Dr. Jansen, who is executive director for microbial vaccine research at Merck's laboratories in West Point, Pa.
"I'm elated that it worked so well," she said. "Usually in science you're bracing yourself all the time for something that doesn't work."
Another source of pleasure and pride is knowing that this drive to wipe out a disease that kills women is being led by two women: herself and Dr. Laura A. Koutsky, a professor of epidemiology at the University of Washington in Seattle.
The vaccine is not available yet. Merck does not intend to market the first vaccine because it is testing a newer version that is expected to prevent 70 percent of cervical cancers instead of 50 percent. Since the tests are not finished, that version will not be ready for about five years. It will be recommended for young people before they become sexually active. Given as three shots over six months, it will prevent cervical cancer but will not treat the disease once it has developed.
The viral origin of cervical cancer, first recognized in 1984, is what makes the disease a target for a vaccine. Nearly all cervical cancers are caused by viruses that belong to a group known as human papillomaviruses, or HPV. They are sexually transmitted, very common and hard to avoid. More than half the adults in the United States have been infected at some time. Condoms may lower the rate of HPV transmission but do not prevent it entirely, probably because the viruses are spread by skin contact and lurk in places that condoms do not cover.
More than 30 types of the virus infect the genital area in humans. Only some types cause cancer; others cause genital warts. A type known as HPV-16 causes 50 percent of cervical cancers, and HPV-18 causes another 20 percent. But even the cancer-causing types are harmless in most people, because their immune systems fight off the virus and make them immune to further infection.
For unknown reasons, however, the virus persists in some women, causing lesions on the cervix. Most go away, but some turn cancerous.
The two women who teamed up against the disease are from different disciplines. Dr. Jansen, 45, was born in Germany and earned her doctorate in microbiology there. She conducted her postdoctoral study at Cornell and worked in Geneva for the drug maker Glaxo before joining Merck. Dr. Koutsky, 50, spent two years in the Peace Corps and worked at the University of Washington for Dr. King Holmes, an expert on sexually transmitted diseases, before earning graduate degrees in public health and epidemiology.
Both women are married to men in related fields, who, they say, accept their passion for work. Neither has children, and both said they doubted they could have accomplished as much as they did if they had been mothers.
In 1993, shortly after Dr. Jansen began working at Merck, the company acquired the license for a technique to make a protein that is part of HPV-16, the virus type that causes half of cervical cancers. The protein, called a viruslike particle, is sort of a fake virus. It does not cause an infection but can act as a vaccine, stimulating the immune system to fight off the real virus.
By that time, Dr. Jansen was an expert on working with yeasts, and she knew they could be genetically engineered to make the viruslike particles.
But how could a vaccine be tested? The conventional wisdom was that most precancerous lesions or cases of cervical cancer took 10 to 20 years to develop. Ethically, women in a study could not be left to develop cancer if precancerous lesions were detected; the lesions would have to be treated. And it could take a decade or more, huge numbers of women and an enormous amount of money to determine whether a vaccine was working. The difficulty of obtaining proof was a major stumbling block, one that made other scientists doubt that a vaccine could ever be brought to market.
Dr. Jansen realized she needed to know more about the course of human papillomavirus infections and how long cervical cancer took to develop, so she began attending conferences on the subject. At one, in 1995, she met Dr. Koutsky.
"It's so wonderful to meet people who are willing to teach you things," Dr. Jansen said. "You end up talking to them for hours and hours. That's how it was. She had one of the very few ? maybe the only study ongoing ? answering some of the critical questions about the natural history of HPV. And she was doing that in a very meticulous and elegant way, following women over many years of time and measuring the infection rate repeatedly to find out exactly what this virus was doing."
Dr. Koutsky said, "I was interested in how people acquire HPV, what the rates of acquisition are, who's at risk for infection, how you detect infection and how long infections persist."
It was exactly the information Merck needed for studies to determine whether a candidate vaccine was effective.
Dr. Koutsky was impressed with Dr. Jansen, she said, adding, "What makes her so terrific is that when she's given a problem she will find the answer."
Among the crucial information Dr. Koutsky provided was that the human papillomavirus infection rates were high, and that young women would develop abnormal Pap smears sooner than many researchers realized. Much of that data, Dr. Koutsky said, came from the work of her colleague Dr. Nancy B. Kiviat, a pathologist. Those findings meant a study would not take 10 years, or even 5, to show results.
"This was different from what other people were reporting," Dr. Koutsky said. "Kathrin took a chance in terms of believing our data. She had to do some convincing of other people at Merck, tell them: `Yes, this may be a bit different from the way other people are talking about HPV and its natural history, but it allows us to design trials that are possible and feasible. And who knows? It might be right.' "
The first study, the one reported in November, included 2,392 women, half vaccinated and half given placebo shots. The vaccine was directed only against HPV-16. It quickly proved itself. After 17 to 27 months, no vaccinated women developed infections or precancerous growths from HPV, whereas 41 nonvaccinated women did become infected, including 9 with precancerous cervical growths. That translated into an efficacy rate of 100 percent.
To be more effective, however, Merck has created another vaccine, against HPV-18 and HPV-16, which together cause 70 percent of cervical cancers. The new vaccine will also protect against HPV types 6 and 11, which cause about 90 percent of genital warts. Although types 6 and 11 do not cause cervical cancer, they cause some of the abnormal Pap tests that needlessly alarm women.
But the main reason for including the wart viruses, Dr. Jansen said, was to "give incentive to young men to also take the vaccine."
Since men spread the viruses that cause cervical cancer, vaccinating them will help reduce transmission. But since the viruses do not harm men, Dr. Jansen said, men would have little incentive to take the three shots. Asked if she thought many men would get the vaccination out of altruism and concern for their partners, Dr. Jansen laughed.
BUT she said that many young men would probably be eager to avoid genital warts because they can turn into large, ugly growths on the penis and may repel sex partners.
The new vaccine is being tested in tens of thousands of young people in the United States and other countries. Results are expected within several years.
Even in countries with widespread screening and relatively few deaths from cervical cancer, like the United States ? which has 13,000 cases and 4,100 deaths a year ? a vaccine would offer great benefits. Besides reducing cancer rates, a vaccine could spare hundreds of thousands of women from cancer scares, a problem that occurs when Pap tests come back abnormal even when it turns out that there is no cancer.
These nerve-wracking episodes happen because human papillomavirus infections are rampant and often cause cervical lesions that are detected by Pap tests. Most of the lesions are harmless and go away on their own, but some turn cancerous ? and there is no way to predict what a given lesion will do. Therefore, all lesions must be monitored, with more Pap tests and other exams, including biopsies sometimes.
Dr. Jansen said that she herself had an abnormal Pap test when she was in her 20's. "I freaked out," she said. "I didn't know anything. Something is abnormal. That's what you hear, even though they deliver the message benignly."
She had a lesion that was treated with cryotherapy, or freezing. "The whole affair is not something you look forward to," she said. "You hope they got everything. It's not a nice experience, so I can sympathize with women."
Dr. Koutsky said: "Many of my friends have daughters who get an abnormal Pap test, and they think their daughters have cancer. To me, there's an enormous burden placed on women." And many more women go through this ordeal than they really need to, she added. "The Pap test is a wonderful screening tool but is not very accurate."
Before the data on the first vaccine study was analyzed, Dr. Jansen said, members of the research team took bets on how effective the vaccine would turn out. "I think I gave it 97 percent, and Laura gave it 98," Dr. Jansen said, adding that the other bets were also in the high 90's.
Nobody was correct, because the vaccine was 100 percent effective.
"We all lost the bet," Dr. Jansen said. "But we were all glad to lose."
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