Cervical cancer vaccine tested

By MARTIN JOHNSTON, health reporter

A vaccine that has shown good results in possibly preventing one of the prime causes of cervical cancer will be tested on up to 300 New Zealand women.

The Auckland and Christchurch women, aged 16 to 23, will be among 5000 in 13 countries testing the effectiveness of the vaccine, being developed by pharmaceutical firm Merck Sharp & Dohme.

The injected vaccine is designed to prevent infection with four kinds of human papilloma virus (HPV): types 6, 11, 16 and 18.

Genetic material from HPV, a common sexually transmitted disease, is found in virtually all cases of cervical cancer. Experts believe other factors, such as cigarette smoking or a weakened immune system, must also be present for HPV to progress to cancer.

A National Women's Hospital gynaecologist, Dr Neil Johnson, said vaccinating people to prevent infection was the next logical step after the practice of screening for cervical abnormalities with smears.

"Obviously it's the big hope and the big promise."

Each year, cervical cancer is diagnosed in about 200 women in New Zealand, and kills about 80.

It is estimated that more than half of sexually active adults will be infected with HPV, of which there are more than 100 types, at some stage in their lives. It is transient in some people, but persists in others.

Types 16 and 18 are associated with up to 70 per cent of all cervical cancer. They are also linked with other genital and anal cancers in men and women.

They do not cause warts, unlike types 6 and 11, which are responsible for about 90 per cent of genital warts.

Condoms provide only limited protection and while genital warts can be treated, there is no cure for HPV.

Merck is one of several companies developing an HPV vaccine.

Preliminary trials of its product, which contains synthetic virus particles, on 2700 women worldwide have shown it to be safe and to produce an immune-system response.

"So far there has been a really good antibody response," said Merck New Zealand's medical director, Dr David Woolner, but the details were a company secret.

"The ultimate vision with this programme would be to prevent enough cervical abnormalities that we did not have to screen. That would be many years away."

Dr Ron Jones, a National Women's gynaecologist who helped write HPV treatment guidelines, said tens of thousands of women each year received some form of investigation for cervical abnormalities.

"This vaccine hopefully is going to prevent many women having abnormal smears and the treatment and complications that can flow from that, including the small number of them who get cancer."

The Family Planning Association is managing the $2 million New Zealand leg of the study and is targeting universities and polytechnics to enrol women. Participants will be given three injections, either of the vaccine or a placebo, in the first six months and will receive regular health checks in the four-year trial.

Merck expects developing a commercial vaccine for 12-year-old girls to take three years after the trial, assuming it proves its effectiveness.

The development of a male vaccine is a year behind the current scheme.

nzherald.co.nz/health