Researchers have developed an experimental vaccine to treat cervical cancer, the leading cause of cancer death among women worldwide.
The World Health Organization estimates that about 500,000 new cases of cervical cancer are diagnosed each year, mostly among women in the poorest regions of the world - sub-Saharan Africa, Latin America and parts of Asia. The disease kills about 274,000 women every year.
Most cervical cancers are caused by infection with the human papilloma virus, or HPV. Two varieties of the sexually-transmitted disease, known as HPV types 16 and 18, cause up to 75 percent of all cervical cancers.
A vaccine already exists to prevent the acquisition and spread of HPV 16 and 18, as well as other strains of HPV that cause genital warts. The new, experimental drug is designed to treat women who already are infected with HPV and who are at risk of developing cervical cancer.
Niranjan Sardesai is chief of research and development for Inovio Pharmaceuticals, a Pennsylvania company developing the therapeutic vaccine.
“Globally, you know, there is a large unmet need in terms of large numbers of women and men who go unvaccinated. So the disease burden is there. And our vaccine, if successful, has the potential to address large populations that are HPV-infected," said Sardesai.
Unlike other vaccines that stimulate an immune response by exposing the body to a bacterial or viral protein, the cervical cancer treatment is what is called a DNA vaccine.
Researchers make the vaccine using small bits of viral DNA that code for a specific protein. Once injected, these DNA fragments direct the patient’s cells to produce copies of the infectious protein, or antigen, that stimulate a strong immune response against HPV-infected cells.
Again, chemist Niranjan Sardesai:
“So our approach works exactly like vaccines do, which is you immunize people with the target protein or the target antigen, have your body produce immune responses against the target antigen, with one major difference - we are asking the body to produce the target antigen on its own to which it can then produce an immune response," said Sardesai.
In a safety and effectiveness trial, the treatment stimulated a strong T-cell immune response in a small number of HPV-infected women. The next step, according to Sardesai, is to conduct a study to see whether the vaccine eliminates HPV infection in a larger group of patients.
Sardesai says the vaccine could potentially treat several cancers stemming from human papilloma virus, including head and neck cancer, vulvar cancer in women, penile and anal cancers, and cancer of the urogenital tract.
An article describing development of the HPV treatment vaccine is published in the journal Science Translational Medicine.