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Drugs, vaccines, and diagnostics: The Pipeline

Vaccines

A number of companies were testing Ebola vaccines when this course was produced. They include:

  • GSK (formerly GlaxoSmithKline). Their vaccine was developed by scientists at the U.S. National Institutes of Health in Bethesda, Maryland.
  • Merck and NewLink Genetics. They are developing a vaccine made by scientists at Canada’s National Microbiology Laboratory in Winnipeg, Manitoba. Animal studies suggest this vaccine may have two possible uses – to prevent infection by being given before exposure and to prevent severe illness or death when given as a prophylaxis* after exposure to Ebola.
  • Johnson & Johnson. They are developing an Ebola vaccine in collaboration with a company called Bavarian Nordic. It requires two injections per person, a technique known as prime-boost.*
  • Profectus Biosciences. They are making an Ebola vaccine that is similar in design to the one made by Merck and NewLink Genetics. Their vaccine requires two injections, given 21 days apart.

Drugs

1) “Repurposed” drugs:

Many drugs that are already approved for use in other conditions have been suggested as possibly being beneficial for Ebola patients. The advantage of such drugs is that researchers already know a lot about their safety, so Phase I can be skipped. The World Health Organization organized a scientific working group to assess the evidence for testing the various drugs. The result, at the time this course was completed: An initial round of trials focusing on two drugs and one treatment.

  • Convalescent serum: Blood from Ebola survivors contains antibodies to fight the virus. A trial in Conakry, Guinea, was established to test whether giving Ebola patients blood from Ebola survivors increases chances of survival. Donors can only give blood to a recipient of a compatible blood type.
  • Favipiravir: An influenza drug also known as T-705. It is licensed in Japan for use against pandemic influenza strains. Early results of a study done in Guinea, announced in February 2015, suggested the drug is useful when given early in the infection but has no effect when given later, when patients are really sick. But this trial did not compare treated people to those in a control group. It instead compared the outcome of patients to people treated at the participating clinics earlier in the epidemic.
  • Brincidofovir: An antiviral* drug being developed to treat other virus infections. It was being tested in Liberia. But Chimerix, the company which is developing the drug, withdrew from the trial and it was halted.

2) Ebola-specific treatments:

Some Ebola-specific drugs and treatments have been under development for a number of years. Some of the leading ones are:

  • ZMapp: A monoclonal antibody* cocktail. Developed by Canadian and U.S. government scientists, this treatment is a mixture of three antibodies that target the Ebola virus. It is given intravenously. ZMapp is being commercialized by U.S. biotech companies LeafBio and Mapp Biopharmaceutical.
  • TKM-Ebola: A drug being developed by Tekmira Pharmaceuticals of British Columbia, Canada. A Phase II trial of the drug started in Sierra Leone on 11 March 2015.
  • BCX4430: An antiviral drug being developed by the U.S. firm Biocryst Pharmaceuticals.

Tip: Be careful about reporting on vaccine and drug trials.

Drug and vaccine trials often raise questions and worries in the population. The way they are set up can be hard to understand, and misconceptions arise easily. Here are some things to be aware of.

  • Know the difference between drugs and vaccines. The words are not interchangeable. See the vocabulary section for definitions.
  • The experimental vaccines cannot cause Ebola. They do not contain live Ebola viruses. The vaccines can cause people to feel unwell for a few days after they are vaccinated. They may have a sore arm, feel achy and some could develop a fever. This does not mean they have Ebola. It means the vaccine has activated their immune system.
  • The same is true for experimental Ebola drugs. They cannot cause Ebola.
  • In clinical trials, some participants don’t get the actual drug or vaccine that is being studied. As we explained before, many studies compare a group of people who get the candidate drug or vaccine to a group that gets a placebo, or dummy, in a randomized controlled trial (RCT). This is the fastest way to discover whether the drug or vaccine really works, and it’s considered an ethical way of doing the study as long as you don’t know if the product works. Ebola is a special case; because the disease is so often fatal, some experts have argued that it’s unethical to withhold experimental products from some trial participants; every volunteer should get the “real” drug or vaccine, they said. Others claim that because an RCT is the fastest way to know whether a drug works, such trials will save more people in the long run. At the time of writing, both types of studies are being done. If some people in a study don’t get the real drug or vaccine, be aware that this has been done after a long debate, and with approval from the government, and that the study participants will have been informed about it.
  • It is possible that someone who gets vaccinated will develop Ebola within a few days. When someone contracts Ebola, it can take up to 21 days for them to become sick. That period from exposure to illness is called the incubation period.* If someone is incubating Ebola, gets a vaccination and then develops Ebola symptoms, they or their family could think the vaccination caused the illness and they could turn to the media to voice concerns. It is important to remember: Ebola vaccines cannot give someone Ebola.
  • If someone takes an experimental drug and dies, it doesn’t mean that the drug doesn’t work. It’s also possible that the person took it too late, and that the virus had already caused too much damage for the drug to work. Or the drug may only help some patients but not all of them, for reasons that are unclear. This is why a study enrolls a large number of people; only when all of them have completed the trial and the results have been analyzed do scientists know whether the drug works or not.
  • If someone takes an experimental drug and dies, it also doesn’t mean that the drug killed them. Any drug can cause side-effects, up to and including death. But if a person becomes severely ill or dies after receiving an experimental drug, it does not mean that the drug caused the decline in their health. The drug may have simply come too late for them. If there are deaths in a clinical trial of experimental drugs, the researchers will investigate closely and will sometimes suspend the clinical trial while they do it. It is important to find out if these events are linked to taking an experimental drug, but be careful about how you report on a situation like this. Do not assume the drug caused the illnesses or deaths.
  • Many people will survive Ebola without drugs. In one MSF study, they showed that a person’s likelihood of survival closely matched the amount of virus they had in their blood when they were diagnosed. So if there is no control group, treating someone who has low levels of virus to begin with could easily give the mistaken impression that a drug worked. Conversely, treating someone who already had a high level of virus  could make it seem that a drug was worthless when it in fact could help healthier people.

Diagnostic tests

Once a person infected with Ebola is diagnosed, he or she can be isolated for care. That helps the patient, but it also helps to stem spread of the disease. People who are cared for at home put their families and neighbors at risk of contracting Ebola.

However, Ebola is hard to diagnose in the early stages of the illness. The symptoms are similar to those of other diseases such as Lassa fever, malaria, and even influenza.

Diagnosis requires a blood test. But you must have a laboratory capable of running Ebola tests to make the diagnosis. In the first few decades of Ebola’s history, blood samples often had to be transported long distances to a lab in a capital city.

In the past decade, scientists who respond to Ebola have developed portable laboratories they can take to the site of an outbreak. But testing still takes several hours. Ideally, health workers could test a person anywhere and immediately tell them the result.

Many teams are working on more rapid tests, and some are coming to fruition. One rapid test, developed by a U.S. company called Corgenix, can provide results within 15 minutes and the testing can be done without electricity, a key advantage when outbreaks are in remote settings with few resources. Another, developed by scientists at the Massachusetts Institute of Technology in Boston, USA, involves strips of specially treated paper that turns color when it comes in contact with blood containing Ebola virus.

This is a field that is evolving rapidly and it will be important that these new tests are both quick and accurate.

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