HPV ( Human Papilloma Virus) is one of the most common sexually transmitted infections and we know that it can cause a wide range of cancers such as cervical, anal and oro-pharyngeal cancers . It is extremely easy to pick up HPV via any form of sexual contact and once infected there is no cure. Some of the less risky strains will disappear by themselves, but the higher risk strains such as HPV 16 and 18 usually don’t. Researchers have been looking at ways to treat HPV infection in the hope of reducing the risk of cancer. Recent results from a phase 2 trial of a therapeutic vaccine being developed by Transgene, has shown promising results.
HPV types 16 and 18 are thought to account for around 70% of cervical cancers. There are currently ways to try and treat the compilations brought on by the infection, but no real effective treatments exist to get rid of the HPV infection itself, before it can lead to cancer. An effective therapeutic vaccine would be the holy grail.
There are 2 categories of HPV vaccine development, preventative and therapeutic. On the preventative side we already have vaccines available that can prevent infection with high risk strains. On the therapeutic front we still have no workable candidate. The recent results however were very promising .Transgene reported that the vaccine resulted in the disappearance of high grade pre-cancerous changes in half of the vaccinated women. They conducted a phase 2 clinical trial in France, in 21 one women. All of the women had HPV 16 -related CIN 2 or CIN 3 ( Cervical Intraepithelial Neoplasia). The women ranged in age from 25-44. All of the women where given the experimental vaccine candidate TG4001 and were observed by colposcopy ( magnified examination of the cervix) every 2 months.
At the end of the 6 month follow up period information was available on 18 of the 21 candidates.
- 9 Women (50%) had no CIN 2 or CIN 3
- Nine out of the 18 woman had no evidence of HPV proteins E6 and E7. These proteins play an important role in the development of HPV related cancers
- There were no serious side effects of the vaccination
They concluded that 50% of the women were spared from having surgery. This is obviously not the end of the story as we will need it to be more effective to prevent all women from having to undergo further surgery, but it is an important step and could be used as an adjunct to current treatments.