More than 40 types of human papillomaviruses (HPVs) can be easily spread through sexual contact and are responsible for more than 14 million new genital HPV infections each year, according to the U.S. Centers for Disease Control. While most HPV infections do not cause cancer, certain strains can persist for many years and may progress to cervical, anal, oropharyngeal, and other types of cancer.
While preventive vaccines exist and provide strong protection against new HPV infections, they are not effective at treating established HPV infections or disease caused by the virus.
Scientists at The Wistar Institute are part of the global effort to reduce and ultimately eliminate cancers caused by HPV. Specifically, the lab of David Weiner, Ph.D., executive vice president, director of the Vaccine & Immunotherapy Center at The Wistar Institute, and the W.W. Smith Charitable Trust Professor in Cancer Research, is using their novel DNA-based vaccine technology to specifically target cancers caused by HPV-16 and HPV-18, the two strains of the virus that are most likely to progress to cancer.
In a study published in 2015 in the journal The Lancet, Weiner and collaborators demonstrated the effectiveness of a DNA-based vaccine for these particular strains of HPV. The study showed that patients with precancerous HPV who received the vaccine were more likely to see their disease regress. This study was notable not just for the positive results but for the fact that it was the first therapeutic DNA-based vaccine to show efficacy. The technology is also being applied to a wide variety of infectious diseases and cancers that the Weiner Lab is studying.
While the initial results were encouraging, the Weiner lab and their collaborators at Inovio Pharmaceuticals, Inc, are continuing to investigate a variety of methods for driving effective immune responses against HPV-related cancers. Megan Wise, Ph.D., a visiting scientist in the Weiner Lab and a postdoctoral fellow at Inovio, is studying various vaccine adjuvants, or additional molecules in the vaccine that can further improve its effectiveness to promote T-cell production and enhance the responses to the vaccine.
“While the preventive HPV vaccine is crucial to helping reduce the burden of HPV-related cancers, many people are still not vaccinated, and the methods of treatment can be invasive and affect a patient’s quality of life,” Wise said. “By studying these therapeutic vaccines, we’re hoping to provide patients with alternative methods of treating this disease.”