17 September 2015. A clinical trial testing a vaccine designed to clear up cervical lesions or sores before they become cancerous, found women receiving the vaccine eradicated more of these lesions than those receiving a placebo. Results of the intermediate-stage trial, funded by Inovio Pharmaceuticals Inc. that makes the candidate vaccine, appear in today’s issue of the journal The Lancet (paid subscription required).
The immunotherapy, code-named VGX-3100 is designed to treat high grade cervical lesions associated with human papillomavirus. These lesions are not yet cancerous, but they occur most often in women age 40 or younger and removal requires surgery, laser, or freezing treatments.
“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,” says Cornelia Trimble, professor gynecology and obstetrics at Johns Hopkins University and the study’s first author. “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,” she adds in a university statement.
VGX-3100 contains synthetic DNA fragments engineered to encourage T-cells in the immune system cells to recognize signature proteins of human papillomavirus types 16 and 18, the two strains of the disease responsible for 70 percent of precancerous cervical lesions and cancer of the cervix. The vaccine is given by injection, followed by electroporation, millisecond electrical pulses creating temporary pores in the cell membrane allowing more ingestion of the synthetic DNA.
This technology was initially developed in the lab of David Weiner, a professor of pathology and immunology at University of Pennsylvania medical school, and licensed by Inovio. Weiner, one of the senior authors of The Lancet paper, and colleagues created some of the earliest DNA-based vaccines for HIV and cancer, and advanced them into clinical stages.
In the clinical trial, 167 women with high-grade or precancerous cervical lesions caused by human papillomavirus were randomly assigned to receive VGX-3100 or a placebo at the beginning of the treatment period, then after 4 and 12 weeks. The study team looked primarily at the extent to which after 36 weeks, high-grade lesions either regressed to low-grade or lower-risk lesions, or were cleared up completely. Researchers also measured the amount of human papillomavirus remaining in the participants.
The results show nearly half (48%) of participants receiving at least one VGX-3100 injection reported regression or eradication of their lesions, compared to 30 percent of individuals receiving the placebo. Of participants receiving all three vaccine injections, half (50%) reported regression or eradication of their lesions, compared to 31 percent receiving the placebo.
Among participants receiving all three immunotherapy injections, about half (52%) reported no residual human papillomavirus, compared to about a quarter (26%) of individuals receiving the placebo. Removal of the virus is important in preventing recurrence of the lesions and possible develpment of cancer. Two individuals had to discontinue receiving the vaccine because of pain at the injection site, while some of the placebo recipients developed skin redness.
“In many of these women, the vaccine not only made their lesions disappear, but it also cleared the virus from their cervix,” Trimble notes. “In most unvaccinated patients whose lesions went away, the virus was still present, and many still had low-grade lesions.”
Trimble says she and colleagues at Johns Hopkins are identifying biomarkers from cervical tissue that predict which lesions are more likely to persist and eventually progress to cancer.
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