The Task Force is supporting the development of two new polio antiviral therapies to treat immune-deficient people who excrete poliovirus after receiving oral polio vaccine (OPV). Development of polio antiviral agents is critical to eradicating the disease.
In rare cases, OPV can cause paralysis or be fatal to individuals whose immune systems may be deficient due to chronic diseases or genetic abnormalities. These people can also potentially transmit the virus to others causing new polio outbreaks.
A study in 13 countries that use OPV, conducted by The Task Force and its partners, determined that as many as two percent of people who receive the vaccine may excrete poliovirus, with approximately half these individuals excreting for six months or longer.
The Task Force is working with the drug developer ViroDefense Inc. to develop two antiviral drugs that will be used in combination to treat immune-deficient individuals who continue to excrete poliovirus after exposure to live oral polio vaccine. The first drug has been evaluated in Phase 1 and 2 clinical studies and is currently being given on a compassionate use basis. The second drug is expected to begin clinical trials in 2018. Both drugs are expected to be available on a compassionate use basis as a combination therapy in early 2020.
“Vaccine-derived polioviruses excreted by immune-deficient individuals represent a risk for reemergence of poliovirus in the post-eradication era,” said Mark McKinlay, PhD, director of the Center for Vaccine Equity at The Task Force. “Poliovirus antiviral agents are the only option for eliminating this source of potential outbreaks.”
Development of the antiviral agents is supported by the Polio Antivirals Initiative (PAI), a collaborative project among The Task Force, the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC), National Institutes of Health, Rotary International, the Food and Drug Administration, and the Jeffrey Modell Foundation. The Task Force serves as the PAI secretariat. The Task Force’s work with ViroDefense is supported by the Bill & Melinda Gates Foundation, CDC, and WHO.
In addition to supporting the development of polio antiviral agents, The Task Force has been a key partner with WHO and CDC in the switch to a safer oral polio vaccine and surveying and containing poliovirus samples within U.S. laboratories.