Research findings by the Partnership for Research on Ebola Virus in Liberia (PREVAIL) are part of presentations and discussions at this year’s annual conference on Retroviruses and Opportunistic Infections (CROI) being held in Boston, Massachusetts, February 22-25.
On Tuesday evening findings from the studies in Liberia were presented at a special session on Ebola. PREVAIL is a clinical research collaboration established in the fall of 2014 by Liberia’s Ministry of Health and the U.S. Department of Health and Human Services.
In February 2015, the partnership launched an Ebola vaccine trial in Liberia as their first study, PREVAIL I. PREVAIL II tested an experimental Ebola treatment known as ZMapp in patients enrolled at sites in West Africa and the United States. PREVAIL III is an ongoing, in-depth study of Liberian Ebola survivors and their close contacts. Key findings presented at the meeting are summarized below.
Initial results from PREVAIL I, a pioneering placebo-controlled clinical trial of two candidate Ebola vaccines launched in Monrovia, in February 2015, indicate that both vaccines stimulate a good immune response in the early weeks after vaccination and are well tolerated, even among people infected with HIV. In an unexpected twist, the study also found that a number of participants had evidence of a past Ebola virus infection, although none reported being aware of having been infected or of being sick. These and other findings from PREVAIL I were described in Boston by one of the co-principal investigators on the study,Fatorma Bolay, Ph.D., Director of the Liberian Institute for Biomedical Research (LIBR).
A first look at results from PREVAIL II – the only clinical trial evaluating whether the experimental Ebola therapy known as ZMapp is safe and effective—reveals that the treatment is well tolerated and suggests it may hold some promise as an Ebola treatment. However, the study could not enroll enough patients to prove that ZMapp offers significantly more healing benefits than supportive care alone.
ZMapp, made by Mapp Biopharmaceuticals, Inc. (San Diego, California), is a mixture of three different anti-Ebola antibodies. Antibodies are infection-fighting proteins produced by the body that attach to the surface of the Ebola virus and thereby prevent it from damaging cells.
PREVAIL III opened on June 17, 2015 at John F. Kennedy (JFK) Hospital in Monrovia. It subsequently expanded to two other sites in locations with larger concentrations of survivors, Duport Road Health Center in Paynesville, a suburb east of Monrovia; and in the neighboring county of Margibi, C.H. Rennie Hospital in Kakata.
The study anticipates enrolling up to 7,500 people, including 1,500 registered EVD survivors and as many as 6,000 of their close contacts. The latter group comprises household contacts of the survivor at the time of diagnosis—spouses and sexual partners, parents, siblings, and children—as well as sexual partners the survivor has had since recovering from EVD.
“By comparing findings from Ebola survivors and their close contacts, we can identify which medical problems are Ebola-specific,” noted Dr. Fallah. “We are also testing blood samples from both groups for anti-Ebola antibodies, a sign of past Ebola infection, and we will be sampling various body fluids to see where and how long survivors can harbor remnants of the Ebola virus.” -Dispatch