A study looking at a vaccine to prevent infection with HPV 16, HPV 18 and cancer of the cervix in young women (PATRICIA)

Cancer type:

Cervical cancer

Status:

Results

Phase:

Phase 3

This trial looked at a vaccine called Cervarix to prevent infection with the human papilloma viruses (HPVs) 16 and 18 in young women aged between 15 and 25.

HPVs are a group of viruses that can infect the neck of the womb (the cervix). The different viruses are given numbers to tell them apart.

Some types of HPV are called ‘high risk’ because they are linked to cervical cancer. Nearly all women with cervical cancer are found to have these high risk types of HPV. Even so, many women who have HPV do not go on to develop cervical cancer.

The HPV virus can cause the cells of the cervix to change and become abnormal. If left untreated these abnormal cells may become cancerous. Women have cervical smears Open a glossary item to pick up abnormal or pre cancerous cells in the cervix.

When this trial was done there was no way to stop women from getting HPV. The aim of this trial was to see if Cervarix could prevent two of the ‘high risk’ types of virus, HPV 16 and HPV 18. If the vaccine worked and prevented infection with HPV 16 and 18, it could reduce the number of women who go on to develop cervical cancer.

Summary of results

The trial team found that Cervarix was useful in preventing infection with HPV 16 and HPV 18.

This trial recruited 18,644 healthy women between the age of 15 and 25.

Half had 3 injections of the Cervarix vaccine
Half had 3 injections of the hepatitis A vaccine – (doctors called this the ‘control group ’)

All the women who took part had 3 vaccinations Open a glossary item over about 6 months. They had a cervical smear before the injections and a check up every 6 months during the trial to see if they had developed HPV 16 or HPV 18. They had a smear test at the end of each year in the trial to see if they had any pre cancerous changes to the cervix.

The researchers looked at the results when 23 women in the trial had pre cancerous changes in the cervix caused by HPV 16 or HPV 18. They found

21 women in the control group had CIN 2 linked with HPV16 or HPV 18
2 women in the Cervarix group had CIN 2 linked with HPV 16 or 18

From their analysis, the researchers say that Cervarix prevented pre cancerous changes (CIN 2 or 3) caused by HPV 16 and HPV 18 in about 90% of women. They concluded that the vaccine worked well against HPV infection and could be used to help prevent cervical cancer.

The side effects for both groups were mild and included injection site reactions such as redness, pain and swelling for a few days. Some of the women who had Cervarix also had headaches and felt tired. But this went away a few days after the injections.

After 3 years, the researchers published some more results. This longer term follow up showed the vaccine continued to prevent pre cancerous changes in more than 90% of women.

We have based this summary on information from the team who ran the trial. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.