A new experimental vaccine shows promise in eliminating both the cervical precancerous lesion and the underlying HPV infection
This therapeutic vaccine triggers an immune system response to attack high-risk HPV types that cause nearly all cervical cancer precursors, known as cervical intraepithelial neoplasia, or CIN.
Cervical precancerous lesions are divided into three grades of severity: CIN 1 lesions generally clear up on their own. CIN 2 lesions often clear up on their own, but can also progress to CIN 3 lesions. CIN 3 is the most severe. It’s a very slow-growing disease, though: fewer than half of CIN 3 lesions will have become cancer within 30 years. All women with CIN 2 or 3 are surgically treated to prevent them from developing cancer.
The therapeutic vaccine, called Tipapkinogen Sovacivec, or TS, is completely different from Gardasil 9, the vaccine given to prevent HPV infection. While Gardasil 9 prevents HPV infection from occurring, TS clears tissue already infected with HPV
The study enrolled 192 women diagnosed with CIN2 or CIN3, randomizing 129 to receive the vaccine and 63 to receive a placebo. Women were given three shots in their thigh, one per week for three weeks. Six months later, the women were treated with standard surgical procedures for CIN 2/3 and the removed tissue was examined.
Women who received the vaccine were more than twice as likely as those who received placebo to see their CIN eliminated regardless of the type of HPV infection. The results were most striking in the more-severe CIN3 where 15- 36 percent of those who got the vaccine saw their CIN3 eliminated, while none of the women in the placebo group did.
The participants were followed for another two and a half years after surgery and results showed that long-term follow-up was better for those who received vaccine over placebo, with more women in the vaccine group remaining completely clear of HPV.
The therapeutic vaccine, called Tipapkinogen Sovacivec, or TS, is completely different from Gardasil 9, the vaccine given to prevent HPV infection. While Gardasil 9 prevents HPV infection from occurring, TS clears tissue already infected with HPV. CIN2 and CIN3 are always caused by high-risk HPV infections.
“The surgical procedure removes all the tissue that is headed towards cancer, but it doesn’t remove all the HPV. You’re not home-free. You still have HPV,” said Diane Harper, M.D., M.P.H., M.S., professor of family medicine and obstetrics and gynecology at Michigan Medicine and a senior associate director of the Michigan Institute of Clinical and Health Research (MICHR).
With the vaccine, researchers found that it not only eliminated the lesions but also eliminated the HPV infection.
“It actually treats the cause of the disease, which is HPV,” Harper said.
Women who received the vaccine injections reported sometimes severe reactions at the injection site as the vaccine is designed to trigger the immune system. The study looked only at cervical lesions, but researchers envision testing TS for other HPV related cancers like head and neck in the future.
The study was published in the journal of Gynecologic Oncology.