As world leaders increasingly recognize the Zika virus as an international public health threat, the Center for Vaccine Development at the University of Maryland School of Medicine's Institute for Global Health has been chosen as one of three study sites in a human safety trial of a new Zika vaccine. The early-stage study will evaluate the experimental vaccine's safety and ability to generate an immune system response in participants.
The selection of the University of Maryland School of Medicine (UM SOM) marks the second time in two years that the School's internationally-acclaimed Center for Vaccine Development (CVD) has been tapped to lead vaccine development efforts in the midst of a growing crisis. In 2014, the UM SOM was the only U.S. medical school asked to join an unprecedented international consortium formed by the World Health Organization. The Consortium resulted in the development of one of the first effective vaccines for Ebola. Recently, the CVD received FDA approval for the first vaccine approved in the U.S. for protection against Cholera. In July, the CVD began malaria vaccine trials in Burkina Faso.
The Zika vaccine trial, which will involve at least at least 80 volunteers at the sites in the United States, is being undertaken by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). The early-stage study will evaluate the experimental vaccine's safety and ability to generate an immune system response against Zika.
Scientists at NIAID's Vaccine Research Center (VRC) developed the investigational vaccine--called the NIAID Zika virus investigational DNA vaccine--earlier this year.
Leading the effort at the UM SOM's CVD is the Center's Director Kathleen Neuzil, MD, MPH, Professor of Medicine and Deputy Director of the UM SOM's Institute for Global Health, who has extensive experience with vaccine research policy and introduction.
"As we learn more about the threat that Zika poses, and as it spreads further and further, the need for a vaccine becomes greater," Dr. Neuzil said. "Our center is gratified that we have been chosen by NIH to be part of this extremely important collaborative effort."
The study is part of the U.S. government response to the ongoing outbreak of Zika virus in the Americas. According to the Centers for Disease Control and Prevention, more than 50 countries and territories have active Zika virus transmission. In the United States and its territories, more than 6,400 Zika cases have been reported. Although Zika infections are usually asymptomatic, some people experience mild illness lasting about a week. However, Zika virus infection during pregnancy can cause a serious birth defect called microcephaly, as well as other severe fetal defects of the brain and other organs. There are no vaccines or specific therapeutics to prevent or treat Zika virus disease.
The NIAID Zika virus investigational DNA vaccine approach is similar to that used for another investigational vaccine developed by NIAID for West Nile virus. That vaccine candidate was found to be safe and induced an immune response when tested in a Phase 1 clinical trial.
The investigational Zika vaccine includes a small, circular piece of DNA--called a plasmid--that scientists engineered to contain genes that code for proteins of the Zika virus. When the vaccine is injected into the arm muscle, cells read the genes and make Zika virus proteins, which self-assemble into virus-like particles. The body mounts an immune response to these particles, including neutralizing antibodies and T cells. DNA vaccines do not contain infectious material--so they cannot cause a vaccinated individual to become infected with Zika--and have been shown to be safe in previous clinical trials for other diseases.
The Phase 1 clinical trial, called VRC 319, is led by Julie E. Ledgerwood, D.O., chief of the VRC's clinical trials program. Volunteers will be divided randomly into four study groups of 20 people each. After enrollment, all participants will receive a vaccination at their first visit via a needle-free injector that pushes the vaccine fluid into the arm muscle. Half of the participants will receive one additional vaccination eight weeks or 12 weeks later. The remaining participants will receive two additional vaccinations: one group of 20 participants will receive a second vaccine at week four and a third at week eight; the other group of 20 participants will receive a second vaccine at week four and a third at week 20. All participants will receive the same dose at each vaccination.
Following each vaccination, participants will remain at the study site for observation for a minimum of 30 minutes so clinicians can monitor for any adverse reactions. Participants will receive a diary card to use at home to record their temperature and any symptoms for seven days following each vaccination.
All participants will return for follow-up visits within a 44-week time period after the first vaccination so investigators can monitor their health to determine if the vaccine is safe. The study team will review patient data daily and weekly to monitor safety. A Protocol Safety Review Team will also conduct formal interim safety reviews.
At follow-up visits, investigators will also take blood samples for laboratory testing to measure the immune response to the vaccine. Participants will be asked to return for two follow-up visits at 18 months and two years following the initial vaccination so investigators can obtain additional blood samples to assess the durability of the immune response.
The other two study sites are Emory University in Atlanta and NIH in Bethesda, Maryland. Initial safety and immunogenicity data from the Phase 1 trial are expected by the end of 2016. If results show a favorable safety profile and immune response, NIAID plans to initiate a Phase 2 trial in Zika-endemic countries in early 2017.
"Zika is an urgent international public health threat, including, now, in parts of our own country," said UM SOM Dean E. Albert Reece, MD, PhD, MBA, who is also vice president for medical affairs at the University of Maryland and the John Z. and Akiko K. Bowers Distinguished Professor. "It is gratifying to see the University of Maryland's Center for Vaccine Development continue to be involved on the front lines of addressing these global threats, as we have done with Ebola and other infectious diseases."
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