With the early success of the “experimental serum” use in the two Samaritan’s Purse volunteers who contracted Ebola Virus Disease (EVD) while treating patients in Liberia, the Centers for Disease Control and Prevention (CDC) published the following Q & A on the topic yesterday.
What is ZMapp?
ZMapp, being developed by Mapp Biopharmaceutical Inc., is an experimental treatment, for use with individuals infected with Ebola virus. It has not yet been tested in humans for safety or effectiveness. The product is a combination of three different monoclonal antibodies that bind to the protein of the Ebola virus.
How effective is the experimental treatment?
It is too early to know whether ZMapp is effective, since it is still in an experimental stage and has not yet been tested in humans for safety or effectiveness. Some patients infected with Ebola virus do get better spontaneously or with supportive care. It’s important to note that the standard treatment for Ebola remains supportive therapy.
This consists of the following measures:
- balancing the patients’ fluids and electrolytes;
- maintaining their oxygen status and blood pressure; and
- treating them for any complicating infections.
Why aren’t more people getting ZMapp?
At this time, very few courses of this experimental treatment have been manufactured. Since the product is still in an experimental stage, it is too early to know whether ZMapp is effective. The manufacturer of this experimental treatment continues to research and evaluate the product’s safety and effectiveness. It has not yet been tested in humans for safety or effectiveness and much more study is needed.
Did the NIH play a role in getting the experimental therapy to the two U.S. patients in Liberia?
This experimental treatment was arranged privately by Samaritan’s Purse, the private humanitarian organization, which employed one of the Americans who contracted the virus in Liberia. Samaritan’s Purse contacted the Centers for Disease Control and Prevention (CDC), who referred them to the National Institutes of Health (NIH). NIH was able to provide the organization with the appropriate contacts at the private company developing this treatment. The NIH was not involved with procuring, transporting, approving, or administering the experimental treatments.
Will patients in West Africa be able to access this experimental treatment? How much supply is there?
The product is still in an experimental stage, and the manufacturer reports that there is a very limited supply, so it cannot be purchased and is not available for general use. The manufacturer has been planning for phase 1 clinical trials and does not have the capacity to manufacture large quantities of the treatment. The drug has not gone through clinical trials, meaning its safety and effectiveness has not yet been tested in humans. The manufacturer of the experimental treatment continues to research and evaluate the product’s safety and effectiveness.
Is ZMapp available under the Food and Drug Administration’s expanded access to investigational drugs?
Currently there are only experimental treatments for Ebola virus infection in the earliest stages of development. When a drug is not approved, the FDA can authorize access to potentially promising products through other mechanisms, such as through an emergency Investigational New Drug (IND) application. In order for an experimental treatment to be administered in the U.S., such a request must be submitted to and authorized by the FDA. The FDA cannot comment on the specifics of ongoing drug development programs and cannot reveal information that is not otherwise public concerning submissions covering such programs such as IND applications submissions. The FDA stands ready to work with companies and investigators treating these patients.
Is ZMapp a vaccine?
No. ZMapp is being developed as a therapeutic product for treatment of people infected with Ebola virus, but not to prevent infection in the same manner as a vaccine. The best way to prevent infection currently is with stringent infection control measures.
What’s the difference between therapy and vaccine?
Vaccines are usually given to people before they are exposed to a virus or bacteria that causes a disease. A vaccine stimulates the immune system to generate antibodies and cellular immunity that can fight off an infection if it were to occur. Typically, therapeutics are provided to people who are already infected with the virus. With the experimental ZMapp treatment, the monoclonal antibodies bind to the virus, so that the human immune system can clear the virus.
Are there Ebola vaccines available for use or in development?
There are currently no FDA approved vaccines for Ebola. The NIH’s National Institute of Allergy and Infectious Diseases is working on developing an Ebola vaccine. NIH recently announced they are expediting their work, and aiming to launch phase 1 clinical trials of an Ebola vaccine in the fall. NIH is also supporting the Crucell biopharmaceutical company in its development of an Ebola/Marburg vaccine as well as Profectus Biosciences in its development of an Ebola vaccine. Additionally, NIH and the Thomas Jefferson University are collaborating to develop a candidate Ebola vaccine based on the established rabies vaccine.
Is the U.S. government involved in the development of ZMapp?
The U.S. government, specifically, the NIH’s National Institute of Allergy and Infectious Diseases, the Department of Defense’s Defense Threat Reduction Agency (DTRA), and the HHS’ Biomedical Advanced Research and Development Authority (BARDA), has provided support for the development of this experimental treatment.
Are there other companies developing experimental treatments or vaccines?
Two other companies, Tekmira and Biocryst Pharmaceuticals, receive funding from the Department of Defense’s Defense Threat Reduction Agency and have therapeutic candidates for Ebola in early development. The Department of Defense is working with a company called Newlink to develop an Ebola vaccine candidate. BioCryst, with NIH support, is working to develop an antiviral drug to treat Ebola virus that is expected to begin Phase 1 testing later this year.