Though the current Ebola outbreak in the Democratic Republic of the Congo remains isolated and thus far unlikely to reach West African outbreak levels, it has reignited conversations around progress against the virus.
"It is important that we continue to try to do research and be ready to respond," said H. Clifford Lane, deputy director for clinical research and special projects at the U.S. National Institute of Allergy and Infectious Diseases, or NIAID, which is part of the National Institutes of Health.
"The best way for us to be able to respond quickly is to have ongoing programs that can evolve as needed," Lane told S&P Global Market Intelligence.
Merck & Co. Inc.'s experimental vaccine against the Zaire strain of the virus — the type of Ebola currently in the DRC and that spread in West Africa during the 2014-15 outbreak — is the furthest along in the pipeline chain.
The vaccine, dubbed V920 and also known as rVSV-ZEBOV, is not yet licensed anywhere in the world. But health officials in the DRC in late May gave the go-ahead for the product to be used during the current outbreak, although the World Health Organization is not recommending it unless there are new confirmed cases.
Merck already has made at least 500,000 doses of the investigational vaccine and expects to file for licensure by the end of this year.
Other vaccine efforts
Elsewhere, Johnson & Johnson and partner Bavarian Nordic A/S are testing a prime-boost regimen for the Zaire strain in phase 2 and 3 studies, usually the last two stages of human trials required for regulatory approval. In the trials, participants will receive a dose of J&J's experimental vaccine candidate Ad26.ZEBOV to prime their system, and two months later, they will get Bavarian Nordic's MVA-BN-Filo to boost their immune response, with the ultimate goal of potentially strengthening and optimizing the duration of the immunity to the virus.
In earlier development is J&J and Bavarian Nordic's multivalent prime-boost vaccine candidate Ad26.Filo + MVA-BN-Filo, which is aimed at combating the Zaire and Sudan Ebola strains, in addition to the related Marburg virus. The vaccine, which is in phase 1 testing, without a completion date set at this time, would be the first of its kind.
In April, the NIAID; the French National Institute of Health and Medical Research, or INSERM; the London School of Hygiene and Tropical Medicine; and health authorities in Guinea and Liberia revealed they were launching a randomized, controlled trial of Merck's and J&J/Bavarian Nordic's monovalent Ebola vaccines, Lane noted.
The phase 2 PREVAC trial seeks to test three vaccine strategies with placebo regimens in 4,900 study participants — 3,500 adults and 1,400 children 1 to 17 years of age — to determine the safety and immune response of the products, he said.
The trial initially will be conducted in Guinea and Liberia, with an additional site planned for Sierra Leone, Lane said. Plans are in the works to add another site in Mali, he said.
"The idea for us is to try to have a regional clinical research network so we can launch some of these protocols more efficiently and in a more coordinated way and we hope that allows us to do them quicker and get results out quicker," Lane said.
All of the partners in the PREVAC collaboration, which is part of the NIAID's PREVAIL series of trials, are providing either financial or in-kind resources, he said, adding that he was not letting President Donald Trump's request to cut the NIH's budget by nearly $6 billion for fiscal year 2018 get in the way of his optimism.
"It's my philosophy that we do these studies planning for them to succeed, not planning ways to mitigate failure," he said. "We will go full-speed ahead to try to get this work done."
GSK positions for quick reactivation
In February 2016, GlaxoSmithKline PLC and NIAID said their experimental Ebola vaccine, known as ChAd3-EBOV, was well-tolerated and induced an immune response in a phase 2 randomized, placebo-controlled trial conducted in Liberia.
But Merck's vaccine, which was tested in the same study, known as PREVAIL-1, showed a slightly better response.
With the outbreak in West Africa declared over in 2015, GSK put its plans for licensure on hold, but said its initiated clinical, nonclinical and stability studies are continuing until completed, and manufacturing and regulatory dossiers also will be finished up accordingly.
"This means we would be well-positioned to quickly reactivate the program if required," a GSK spokeswoman told S&P Global Market Intelligence.
Motivation for investment
While the World Health Organization has called for support to develop vaccines against two other strains, Taï Forest and Bundibugyo, Luis Encinas, an Ebola expert with Médecins Sans Frontières, said he thinks it is unlikely those would be pursued in the current environment.
"It's clear that the motivation, or the next strong investment, will be when the next Western country is affected by Ebola," he said in an interview. "This is a very vicious circle, because you cannot push for the R&D if you have no patients."
There have been moves to fund early research and draw companies into the vaccine space. The Coalition for Epidemic Preparedness Innovations, an alliance formed earlier this year to finance and coordinate the development of new vaccines, has about $500 million in the bank so far and has called for proposals.
But companies will never reap profits from developing these vaccines, said Mike Turner, head of infections and immunobiology at the U.K.-based Wellcome Trust, whose organization is part of the alliance.
"We're now asking them to do something essentially for the public good rather than the commercial benefit," he said in an interview. "When we frame it that way, I'm just impressed they've actually stepped up to the mark and been good citizens."
Ebola treatment R&D
There currently are no drugs approved by the U.S. Food and Drug Administration to treat Ebola.
Mapp Biopharmaceutical Inc.'s ZMapp, a cocktail composed of three humanized monoclonal antibodies manufactured in tobacco plants bioengineered specifically to produce large quantities of the proteins, is the furthest in development.
Results of the PREVAIL-2 study reported in February 2016 indicated ZMapp was well-tolerated and showed promise in patients with Ebola, the company's president, Larry Zeitlin, told S&P Global Market Intelligence.
Zeitlin noted that Mapp was granted an expanded access protocol for use of ZMapp in the four countries that participated in the PREVAIL-2 study: Liberia, Sierra Leone, Guinea and the U.S. He said the protocol also would also cover use in the DRC.
Zeitlin said Mapp is working under a partnership with the U.S. Biomedical Advanced Research and Development Authority, or BARDA, to advance ZMapp toward U.S. licensure under the FDA's animal rule, which permits a drug's effectiveness to be demonstrated in animals when it is unethical or not feasible to conduct controlled clinical trials in humans.
Regeneron Pharmaceuticals Inc. also is pursuing development of an antibody cocktail for Ebola, known as REGN3470-3471-3479, which is in phase 1 testing in healthy volunteers. Regeneron also has received BARDA funding to advance its experimental Ebola product.
Gilead's experimental nucleotide analogue GS-5734, a small molecule, also was used under an expanded access protocol toward the end of the West African outbreak. The biotech has contacted public health agencies about the drug's potential use in the DRC and is preparing for potential requests to supply it, Gilead spokesman Nathan Kaiser told S&P Global Market Intelligence.
Also in the chase for an Ebola drug is Fujifilm Holdings Corp., whose healthcare division is developing its antiviral Avigan, also known as favipiravir, as a potential treatment for the virus. The drug is approved in Japan to treat influenza.
INSERM and the government of Guinea conducted trials of Avigan during the 2014-15 outbreak. Based on the outcome of the trials, the Guinean government selected Avigan as a "standard treatment," company spokesperson Kana Matsumoto told S&P Global Market Intelligence.
MSF and another humanitarian medical group, Alima, has contacted Fujifilm about the use of Avigan in the DRC, but Matsumoto said the firm does not expect a formal request for supply of the medicine to be made.