HIV Drug Lopinavir Could Prevent Cervical Cancer
Lopinavir, an antiretroviral drug used to treat HIV, could help prevent cervical cancer caused by the human papilloma virus (HPV), according to researchers from two continents. HPV is the most common cause of cervical cancer.
Cervical cancer is difficult to detect early
Cervical cancer is typically a slow-growing disease that may not have symptoms, yet it can be detected early with regular Pap tests. An estimated 12,200 cases of the disease were diagnosed in the United States in 2010, according to the National Cancer Institute, and more than 4,000 deaths were estimated to be caused by the disease.
Women can have HPV, which is transmitted via sexual contact with an infected individual, for many years before it can lead to cervical cancer. If the cell changes that result in cervical cells can be treated, it is possible to prevent cancer.
Researchers from the University of Manchester, along with colleagues in Canada, discovered how lopinavir triggers a natural viral defense system in HPV-infected cells. The Manchester team had previously worked with lopinavir in cell cultures and had some success against HPV-infected cervical cancer cells.
In the new study, the researchers “found that lopinavir selectively kills HPV-infected, non-cancerous cells, while leaving healthy cells relatively unaffected,” according to Dr. Ian Hampson, of Manchester’s School of Cancer and Enabling Sciences.
The other critical finding by the research team is how lopinavir works. Hampson explained that “we were also able to show that lopinavir kills these HPV-infected cells by re-activating a well-known antiviral system that is suppressed by HPV.” In addition, lopinavir is also much less toxic to healthy, non-HPV infected cells.
These findings are significant for several reasons. One is that current HPV vaccination programs are not effective in women who are already infected with HPV, and the vaccines are not able to protect against all types of HPV. The vaccines are also expensive, which limits their use in developing countries.
Lopinavir may provide an inexpensive, more readily available way to help eliminate early HPV infections and prevent development of cervical cancer, which is responsible for about 290,000 deaths per year around the world.
Hampson noted that the drug’s delivery system would likely need to be as a cream or pessary to effectively treat cervical cells. That’s because in order for the drug to work against HPV, the virus-infected cervical cells require about 10 to 15 times the concentration used in lopinavir tablets.
Dr. Lynne Hampson, a co-author of the study, noted that while the HIV drug is safe when taken orally, ”our latest findings provide very strong evidence to support a clinical trial using topical application of this drug” in an effort to help prevent cervical cancer.
Hampson L et al. Antiviral Therapy 2006; 11(6): 813-25
National Cancer Institute
University of Manchester, news release May 3