- The only way we’re going to find out for sure if experimental Ebola drugs are effective is to use them in sick patients.
- For drugs targeted to Ebola, where these medicines have already proven some benefit in animal testing,it’s imperative we get these medicines into the field.
- There are at least three vaccines in development for Ebola that are garnering attention.
The World Health Organization said last Thursday that the scope of the Ebola outbreak may be vastly underestimated, and will grow worse before they are able to get the epidemic under control.
Amid these dire warnings, and facing a virus with no proven remedies, treatments, or vaccines, a panel of WHO ethicists approved the use of experimental therapies in stricken patients.
It was the right decision for a host of reasons. In fact, it shouldn’t have been ethicists who reached such a conclusion. Drug regulators should have taken this decision.
Patients facing a deadly virus with no proven treatments deserve access to experimental drugs, so long as they provide informed consent to receive them. Such forward deployed drugs should already have established basic proof of safety, and there should be a plausible reason to believe that these agents could also prove effective.
But there’s another reason to forward deploy these experimental treatments. It’s the only way we are ever going to find out if they work, and put them to wider use.
In fact, regulatory policies in the U.S. allow for drugs to be approved on the basis of studies in animals alone when there is no ethical way to test a medicine in sick patients. In the case of Ebola, you can’t purposely infect someone with the virus so that you have a subject to test a treatment on. You need to wait for an outbreak.
The only way we’re going to find out for sure if these experimental Ebola drugs are effective is to use them in sick patients. Given the state of science, this initial use is going to based on little more than information about their effectiveness in animals.
FDA issued a so-called “animal rule” almost a decade ago (amid fears of bioterrorism after the deadly anthrax attacks) outlining how a drug could be approved on the basis of only efficacy studies in animals. It was rightly acknowledged that animal testing alone would have to form the basis of approval when we were dealing with therapeutics that targeted rare and deadly diseases that could be used as weapons.
The same challenges surround drugs targeted to Ebola.
Given the scope of the current outbreak, after experimental Ebola treatments have already proven some benefit in animal testing (and where some measure of their safety has also been established) it’s imperative that we get these drugs into the field.
Regulators, for their part, should be making sure these drugs are delivered in a way that allows us to learn about whether the treatments are working, and use this information to form the basis of potential regulatory approvals. There simply is no other way to test medicines against deadly and rare pathogens like Ebola.
So what are the treatments that are furthest along, and could be deployed in an expanding epidemic? Some of the drugs, like the antibody treatment from Mapp Pharmaceuticals, have already garnered a lot of attention. Mapp’s experimental Ebola treatment Z-Mapp was already administered a Spanish priest who later died and two U.S. aid workers who are reported to have shown signs of recovery.
Here are some of the other experimental treatments that are in development. Some of these compounds could be forward deployed if the outbreak continues:
There are at least three vaccines in development for Ebola that are garnering attention. One of the vaccines, developed by a government laboratory in Canada, has already been shipped to the World Health Organization, presumably for use in Africa. About 1,000 doses of the vaccine, licensed to NewLink Genetics, a company in Ames, Iowa, may be tested in first responders, including healthcare providers, according to reports. Charles Link, the chief executive, said NewLink could manufacture tens of thousands of doses over the next couple of months.
The NIH and GlaxoSmithKline (a company I advise on unrelated matters as a member of GSK’s Product Investment Board) are developing another vaccine. There are 400 doses available now,according to reports — enough for a clinical trial in healthy adults, federal official are saying.
The United Kingdom’s Telegraph reports that GSK is planning to test the vaccine on a small group of people at the NIH Vaccine Research Centre in Maryland later this year. As part of this process, the NIH will recruit health volunteers to inject them with the experimental vaccine. The aim of this early stage testing is see if the product is safe and helps people mount an immune response that would confer protection against a future exposure to Ebola. This process normally takes up to six months. GSK is hoping to report the results by the end of the year.
Bavarian-Nordic, a biotechnology company located in Denmark, also has a vaccine in development that can protect against multiple hemorrhagic fevers, including Ebola. The vaccine is based on the same platform that the company used to develop its smallpox vaccine Imvamune.
Among the companies developing therapeutics, a lot of the early attention has focused on Mapp Pharmaceutical’s product ZMAPP. This is a antibody drug (developed in a tobacco plant) that directly attacks the virus. It has already been studied in monkeys. In those trials, macaque monkeys were able to survive infection with Ebola, and develop a robust and durable immune response against the virus.
It is based on these studies, some of the most advanced with any available treatment for Ebola, that ZMapp has already been used (amidst some controversy) in a number of doctors who were infected with Ebola during the current outbreak. However manufacturing the antibody drug is a long process, and Mapp does not have a facility capable of making the drug at large scale. As a result, existing supplies of the drug have already been exhausted, and it will take several months to develop a new stock.
The biotech company Tekmira (NASDAQ:TKMR) has also received attention for a drug that it is developing under the FDA’s Animal Rule. The product, which uses RNA interference to directly target the Ebola virus, is currently in Phase I clinical studies.
In a paper published in the medical journal Lancet, Tekmira showed that the product consistently conferred post-exposure protection in primates exposed to Ebola. However, in these primate studies the drug also caused some serious (but temporary) side effects, which seemed to be a consequence of cytokine release, a marker of an immune response that the drug was generating in the monkeys. Temira, a public company, has an existing contract with the U.S. Department of Defense to develop the experimental Ebola compound that is worth $140 million.
Another private biotechnology company, MediVector, has developed a compound against invluenza (Favipiravir) that it believes can also be used as a treatment against Ebola. The compound is believed to be effective against a wide variety of RNA viruses, which is what’s raising hopes that it could be used against Ebola. The company has a contract with the U.S. DoD. MediVector has been asked to prioritize animal studies evaluating Favipiravir against Ebola. It has studies underway with Ebola-infected monkeys, and expects to have the initial results this fall.
SIGA (NASDAQ:SIGA) is an anti-infective company headquartered in New York is working closely with federal agencies to develop a range of compounds that target diseases that could be used as bioweapons, such as smallpox. The company has one compound that it is developing to target filo-viruses such as Ebola.
SIGA uses analytical tools to evaluate the bacterial and viral genomes to find new targets against these bugs. The company is currently testing three different experimental drugs. SIGA’s compounds work by trying to prevent the Ebola virus from entering host cells. This would block the ability of the virus to replicate.
The biotech company Sarepta (NASDAQ:SRPT) also developed a potential treatment for Ebola that had success in combatting the disease in primates. The drug’s development stopped two years ago when government funding dried up, but Barrons reports that Sarepta still has enough of the drug on hand to treat a few dozen patients.
Some scientists also think statins, a drug already in widespread use for lowering cholesterol, could help combat Ebola. The statins don’t attack the virus directly. The theory is that the statins help reduce the extent of the immune system reaction that Ebola triggers in infected people. It’s the immune response that we mount to the virus that inflicts a lot of the lethal damage that the virus causes to our bodies.
In all of these cases, if these experimental drugs are going to see action in the current outbreak, the companies involved (and drug regulators) should make sure that we are collecting information on how these drugs perform. The results of this unfortunate but necessary use of these agents may be the best information we’re going get to support the approval of a successful treatment.