Vaccine to prevent cervical cancer shows promise

Scientists have used a genetically engineered vaccine to successfully eradicate high-grade precancerous cervical lesions in nearly one-half of women who received the vaccine in a clinical trial.
The goal was to find nonsurgical ways to treat precancerous lesions caused by HPV, scientists said.
"Every standard therapeutic option for women with these lesions destroys part of the cervix, which is particularly relevant for women of childbearing age, who may then be at risk for preterm birth due to a weakened cervix," said Cornelia Trimble, professor at the Johns Hopkins University School of Medicine.
"A vaccine able to cure precancerous lesions could eventually be one way women can avoid surgery that is invasive and can also harm their fertility," said Trimble, first author of the new report published in The Lancet journal.

High-grade cervical lesions, termed CIN2/3, occur most often in women 40 or younger, according to Trimble.
Because the lesions can progress to cancer, they are usually removed by surgery, freezing or laser. The procedures are successful in removing the precancerous areas in approximately 80 per cent of women, said Trimble.

Less troublesome lesions, called low-grade dysplasia, are usually monitored by physicians rather than immediately removed because they pose less of a risk for cancer and usually regress on their own.
For the study, the scientists used a vaccine, originally developed by University of Pennsylvania scientist David Weiner, which is engineered to teach immune system cells to recognise precancerous and cancerous cells.

Those cells are coated with proteins linked to an infection with two strains of HPV - 16 and 18 - that cause cervical cancer.
Between 2011 and 2013, the scientists recruited 167 women, ages 18 to 55, with newly diagnosed, high-grade precancerous cervical lesions.
The women were randomly assigned to receive either three doses of the vaccine or saline injections over a 12-week period at 36 hospitals and private gynecology practices in the US and six other countries.
After each of the injections, the scientists gave the women a small electric pulse at the site of the injection.
Cells near the electric pulse open their pores, said Trimble, increasing the likelihood that the vaccine will be taken up by immune system cells.

Of 114 women who received at least one vaccine dose, 55 (48.2 per cent) had a regression of their precancerous lesion, meaning their lesions disappeared or converted to low-grade lesions, compared with 12 of 40 (30 per cent) who received saline injections.
Of the 114, 107 received all three vaccine doses, and 53 of them (49.5 per cent) had regression of their lesions. Of the 40 in the saline group, 36 got all three injections, and 11 of them (30.6 per cent) had regression of their lesions.
Among women who completed all three injections, scientists could find no trace of HPV in the cervixes of 56 of the 107 women who received the vaccine, compared with only nine of 35 saline recipients.