Prior to the current outbreak in West Africa, Ebola garnered little global attention. Previous outbreaks elsewhere in Africa were relatively small and self-limiting, although still devastating to those communities that were affected.1 As is the case with many other neglected tropical diseases, Ebola was not a major target for pharmaceutical research and development (R&D)—there simply was not a sufficient market demand for drugs and vaccines to cure and prevent Ebola virus infections. Yet, despite the lack of financial incentive, in 2015 we do have a number of vaccine and drug candidates in development, which may help in containing the current or future outbreaks.
The Ebola medical countermeasures (MCM)—drugs, vaccines, and diagnostics—being discussed and tested today have been developed with the significant investment in biodefense programs over the past decade. Ebola virus is a Category A priority pathogen, and it is judged to be one of a few biological agents that pose the “highest risk to national security and public health.”2 Because Ebola has been identified as a Category A pathogen, the federal government has dedicated resources to developing medical countermeasures to be used in the event that Ebola is used against the US in a bioterrorism attack.
The US government has made sustained biodefense-related investments in basic and applied R&D aimed at producing anti-Ebola MCMs for more than a decade.3 Investments made by the National Institute of Allergy and Infectious Diseases (NIAID), through Biodefense and Emerging Infectious Diseases Program funding, and by the Department of Defense (DoD) Defense Threat Reduction Agency (DTRA), through the Chemical and Biological Defense Program (CBDP), have led to the development of a majority of the countermeasures in the pipeline.3 In addition, biodefense investments in building advanced development capabilities at the Biomedical Advanced Research and Development Authority (BARDA) and in building mechanisms for emergency clinical testing and emergency regulatory approval at the Food and Drug Administration (FDA) are now proving critical to current efforts to rapidly confirm safety and efficacy and ramp up production of countermeasures.
NIAID has been a major source of Ebola research and research support as part of the US biodefense enterprise. NIAID works to understand the pathophysiological processes that make Ebola and other Category A pathogens so worrisome to public health and national security agencies; it works to develop animal models that can be used to test the efficacy of countermeasures and develops treatment strategies for viral hemorrhagic fevers and other diseases.4
Since fiscal year (FY) 2004, NIAID has invested over $333 million specifically focused on Ebola, including basic research on the virus and research toward development of vaccines, therapeutics, and diagnostics (Martin Johnson, Chief, Resource Planning and Mission Integration Branch, NIAID, NIH, personal communication, September 19, 2014) (see Table 1).
Table 1.
NIAID Support for Ebola Research FY2004-13 (in $Millions)
| Fiscal Year | Basic | Vaccine | Therapeutics | Diagnostic | Total |
|---|---|---|---|---|---|
| 2004 | 6.06 | 15.15 | 1.88 | 17.03 | |
| 2005 | 8.48 | 16.04 | 4.94 | 20.97 | |
| 2006 | 7.83 | 31.70 | 19.48 | 51.18 | |
| 2007 | 6.43 | 31.18 | 3.09 | 34.27 | |
| 2008 | 7.93 | 11.61 | 30.59 | 0.15 | 42.34 |
| 2009 | 15.48 | 20.84 | 6.22 | 0.12 | 27.18 |
| 2010 | 11.69 | 37.16 | 8.85 | 0.91 | 46.93 |
| 2011 | 13.80 | 17.57 | 8.67 | 2.84 | 29.08 |
| 2012 | 13.56 | 22.51 | 9.52 | 2.92 | 34.95 |
| 2013 | 131.37 | 17.19 | 10.31 | 1.86 | 29.35 |
| Total | 222.63 | 220.94 | 103.55 | 8.79 | 333.29 |
Note. Adapted from personal communication with NIAID. Funding amounts were provided by NIAID in September 2014. Amounts here exclude funding as part of the American Recovery and Reinvestment Act (ARRA).
DoD has also invested in medical countermeasures development for hemorrhagic fever viruses as part of their agency-wide Chemical and Biological Defense Program. According to a press release by DoD, DTRA has invested over $300 million since FY2003 in basic and applied research programs that work to develop vaccines, drugs, and diagnostics for Ebola and other diseases, although further breakdown of this funding was not provided by DTRA.5 This research has been conducted with the primary purpose of protecting the warfighter, yet these investments are also proving to have benefits for civilian populations. Support provided by DTRA, the US Army Medical Research Institute of Infectious Diseases (USAMRIID), and the Defense Advanced Research Projects Agency (DARPA) for research on Ebola has contributed to a number of countermeasures that may be useful in the current crisis if they are ready and scaled up in time.
As a direct result of US biodefense investments since 2003, there are at least a dozen vaccines and therapeutics in the pipeline for Ebola (see Table 2). Many of these countermeasures are currently in phase 1 clinical trials, and for some phase 2 and 3 clinical trials have begun or are being planned for 2015. A number of the therapeutics under development have been provided to Ebola-infected patients in this outbreak under “compassionate use” regulations, which allow for use of promising but experimental drugs and vaccines for patients with life-threatening illnesses.28 While conclusions cannot be drawn from the few patients who have received experimental treatments, it is noteworthy that drugs and vaccines were available to give in limited quantities.
Table 2.
Major Experimental Ebola Medical Countermeasures in Advanced Development as of December 18, 2014
| Product Name | Developer(s) | Mechanism of Action | Evidence of Efficacy | Development Phase | References | |
|---|---|---|---|---|---|---|
| Vaccines | ChAD3 | NIAID, GSK, Okairos | Uses chimp adenovirus 3 with glycoproteins (GP) from Ebola Sudan and Ebola Zaire | In nonhuman primates (NHP), there is 100% protection when given pre-exposure. | In Phase 1 clinical trials in the US, UK, Denmark, and Mali. Results from the US trial show an acceptable safety profile and evidence that the vaccine produced an immune response. Phase 2/3 clinical trials are beginning in early 2015 in West Africa. | 6, 7, 8 |
| VSV-ZEBOV | Merck & Co, Public Health Agency of Canada, NewLink, DTRA | Uses vesicular stomatitis virus (VSV) with Ebola Zaire GP exchanged for native VSV GP | In nonhuman primates, there has been 100% protection when given 21 days before exposure. Efficacy when givin within 1 hour postexposure is 30-50%. | In Phase 1 clinical trials in Switzerland, the US, Canada, Germany, Gabon, and soon in Kenya. The Phase 1 trial in Geneva was halted due to reports of joint pain in some of the participants but has now resumed. Phase 2/3 trials are planned for early 2015 depending on the Phase 1 outcomes. This vaccine has been used in response to a laboratory accident in Germany and in some patients evacuated to the US in the current outbreak. | 8, 9, 10 | |
| VesiculoVax™ Zaire-Ebola | Profectus BioSciences, NIAID, DoD, Galveston National Laboratory | Recombinant VSV (N4CT1) vectored Zaire-Ebola vaccine. This platform is also used for an rVSVN4CT1-vectored Marburg vaccine and a trivalent Ebola/Marburg vaccine. | In nonhuman primates, there is 100% protection when given a single dose pre-exposure. | Phase 1 clinical trials are being planned and funded for early 2015 for both the Zaire-Ebola virus vaccine and the trivalent Ebola/Marburg vaccine. | 11, 12 | |
| MVA-BN® Ebola and Filo | Bavarian Nordic, NIAID | Modified Vaccinia Ankara virus platform for an Ebola-Zaire vaccine and a multivalent vaccine to protect against Ebola (Zaire and Sudan) and Marburg | Preclinical testing in animals shows complete protection from Ebola Zaire species with the Ebola vaccine. | Phase 1 clinical trials have begun in the UK for the multivalent Ebola Zaire, Ebola Sudan, Marburg vaccine. Results are expected in early 2015. | 13, 14 | |
| Combination MVA-BN®/AdVac® | Crucell/Bavarian Nordic/NIAID/USAMRIID | Recombinant, multivalent adenovirus/MVA vacccine for Ebola and Marburg | The combination vaccine has shown complete protection in preclinical testing against Ebola. | Phase 1 clinical trials began for this vaccine in January. | 8, 15, 16 | |
| EBOV GP Vaccine | Novavax | Adjuvanted Ebola GP recombinant nanoparticle vaccine based on the 2014 Guinea Ebola strain | Rodent and NHP studies have shown high titers of neutralizing antibodies specific to the 2014 Guinea Ebola strain. | Phase 1 clinical trials are ongoing in Australia. | 16, 17, 18 | |
| VXA ZBOV-GP | VaxArt/Lonza | Recombinant VSV-VECTOR vaccine used in HIV-1 vaccine candidates. Using replication-competent live oral monovalent virus vaccine (Zaire Ebola strain). | NHP studies showed complete protection with a single dose. | Phase 1 clinical study is planned for 2015 in the US. | 16, 18 | |
| Recombinant rabies vector Ebola vaccine | Thomas Jefferson University/NIAID/IDT Biologika/Exxell Bio | Inactivated recombinant rabies vaccine expresses Ebola GP | Vaccine has been shown to be safe and to induce both rabies and Ebola specific protection in non-human primates. NHP challenge studies showed complete protection against Ebola with a single dose. | Phase 1 clinical study is planned for mid-2015 in the US. | 8, 18, 19 | |
| Therapeutics with Antiviral Activity | Zmapp | Mapp (Leaf) Biopharmaceutical, DARPA, NIAID, DTRA | Triple monoclonal antibody cocktail neutralizes virus and kills infected cells. | In NHP, there is 100% treatment efficacy when initiated at 5 days postinfection. | The drug has been used under emergency investigational new drug application (eIND) for cases of compassionate use in this outbreak in Ebola-infected patients in Africa and patients evacuated to the US and Europe with inconclusive benefits. Phase 1/2 trials planned in the US and West Africa in early 2015. Few doses of the drug are available due to the current method of production in tobacco plants, which takes time. Mapp is exploring an alternative manufacturing system to increase production and has partnered with BARDA. | 8, 20 |
| TKM-Ebola | Tekmira Pharmaceuticals, USAMRIID, DTRA | Cocktail of 2 small interfering RNAs (siRNAs) in lipid nanoparticle target the viral proteins VP35 and L polymerase to silence viral genes. | In NHP, efficacy is 83% when initiated 48 hours postinfection and 67% when initiated 72 hours postinfection. | This drug has been used under eIND for cases of compassionate use in some Ebola-infected patients in the US. A Phase 1 single ascending dose (SAD) study was completed, and discussions for Phase 1 clinical trials are under way. | 20, 21 | |
| BCX4430 | BioCryst Pharmaceuticals, Inc./NIAID/USAMRIID | Small molecule, viral polymerase inhibitor | In vitro mouse studies show efficacy. NHP studies showed good protection. | Phase 1 clinical trials are under way with NIH. | 20, 22 | |
| Brincidofovir (CMX001) | Chimerix | Small molecule, viral polymerase inhibitor | In vitro activity against filoviruses seen. Cannot evaluate in NHP due to metabolism. Used in Dallas patient unsuccessfully, but given late in the course of disease. | Human clinical trials are now under way, led by MSF at an Ebola treatment facility in Liberia. Trials are not randomized, and no patients will receive placebo. Any patients diagnosed with Ebola at the ELWA 3 treatment center can opt to receive the drug. | 20, 23 | |
| Human Convalescent Serum | N/A | Passive transfer of antibodies in human serum | A single report from the 1995 Kikwit Ebola outbreak, where 8 seriously ill patients received transfusion; 7 of 8 survived, but unable to differentiate effect of supportive care vs. use of convalescent serum. Has been used in this outbreak with indeterminate results. | WHO has issued interim guidance on the use of convalescent whole blood or plasma. Discussions about clinical trials and use during the outbreak are under way. | 24 | |
| AVI-7537 | Sarepta, USAMRIID | Phospho Morpholino Oligonucleotide (PMOs) blocks viral protein production. | In NHP, treatment efficacy is 60-80% when initiated 1 hour postinfection. | Under IND for human clinical trials. Phase 1 SAD completed with no safety issues. Support for clinical trials is under consideration. | 25, 26 | |
| Favipiravir (T-705) | Medivector/Toyoma/Fujifilm/DTRA | Small molecule, viral polymerase inhibitor | In vitro mouse studies show it is less active against Ebola than influenza. NHP efficacy studies under way. | Conditionally approved in Japan for novel influenza and in Phase 3 for uncomplicated influenza. There are reports of compassionate use in Ebola patients in Europe. Phase 2/3 clinical trials began in Guinea in December 2014. | 8, 27 |
Note. Adapted from a presentation by Dr. Peter Jahrling at the JHSPH Ebola Crisis Dean's Symposium on October 15, 2014. Information has been updated.8
Current Funding Picture
Recently, NIH and DoD have continued to provide support for advancing research into many of the countermeasures included in Table 2. They have also provided support for clinical trials and have partnered with private sector pharmaceutical companies to expand production capacity of countermeasures for use in clinical trials. Some of the funding for these efforts has been derived from current MCM budgets, and other funding has been reprogrammed. In October 2014, Congress gave approval for reprogramming $750 million in DoD war funds to support Operation United Assistance, the deployment of military assets to assist the government of Liberia. As of December 1, 2014, $25.6 million of the $750 million in funding had been expended by DoD for Ebola countermeasures research and development.29
Going forward, on December 16, 2014, the President signed into law the Consolidated and Further Continuing Appropriations Act, 2015, which appropriates a total of $5.4 billion in emergency funding to support the US response to Ebola. Of that total, approximately $1.1 billion will go to Ebola MCM research, development, procurement, and approval (see Table 3).30
Table 3.
Ebola Countermeasures-Related Funding in the FY2015 Omnibus (in $Millions)
| Department/Agency | Primary Purpose of Funds | Appropriations Amount |
|---|---|---|
| HHS, Food and Drug Administration (FDA) | Review, regulation, and postmarket surveillance of MCMs, and administrative activities | 25 |
| Department of Defense (DoD) | $17 million for MCM procurement and $95 million for MCM RDT&E | 112 |
| NIH, National Institute of Allergy and Infectious Diseases (NIAID) | Ebola countermeasures R&D | 238 |
| HHS Office of the Secretary (PHSSEF) (BARDA) | To develop and purchase countermeasures, vaccines, diagnostics, and medical supplies | 733 |
| Total | 1,108.00 |
Note. Adapted from the text of H.R. 83, the Consolidated and Further Continuing Appropriations Act, 2015.30
Future Investments Needed
The current Ebola crisis has shown that investments in biodefense and health security have benefits beyond enhancing our preparedness for bioterrorism and deserve increased and sustained support over the long run.
References
- 1.Outbreaks chronology: Ebola virus disease. US Centers for Disease Control and Prevention; website. Updated December18, 2014. http://www.cdc.gov/vhf/ebola/outbreaks/history/chronology.html Accessed December18, 2014 [Google Scholar]
- 2.Biodefense and Emerging Infectious Diseases: NIAID emerging infectious diseases/pathogens. National Institute of Allergy and Infectious Diseases; website. Updated August8, 2014. http://www.niaid.nih.gov/topics/BiodefenseRelated/Biodefense/Pages/CatA.aspx Accessed December19, 2014 [Google Scholar]
- 3.Boddie C, Sell TK, Watson M. Federal funding for health security in FY2015. Biosecur Bioterror 2014;12(4):163-177 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Emerging viral pathogens section. National Institute of Allergy and Infectious Diseases; website. Updated June1, 2011. http://www.niaid.nih.gov/labsandresources/labs/aboutlabs/emergingviralpathogens/Pages/default.aspx Accessed December18, 2014 [Google Scholar]
- 5.Pellerin C.DTRA medical countermeasures help West African Ebola crisis. DoD News December12, 2014. http://www.defense.gov/news/newsarticle.aspx?id=123822 Accessed December19, 2014
- 6.Pollack A.Trial of Ebola Vaccines' Effectiveness is Announced. New York Times January23, 2015. http://www.nytimes.com/2015/01/23/business/international/trial-of-2-ebola-vaccines-effectiveness-is-announced.html?_r=0 Accessed January29, 2015
- 7.NIAID/GSK experimental Ebola vaccine appears safe, prompts immune response [news release]. November28, 2014. National Institutes of Health; http://www.nih.gov/news/health/nov2014/niaid-28.htm Accessed December19, 2014 [Google Scholar]
- 8.Jahrling P.Overview of lead experimental medical countermeasures for Ebola and product-specific considerations. Presentation at the JHSPH Ebola Crisis Dean's Symposium; October15, 2014; Baltimore, MD http://www.jhsph.edu/events/2014/ebola-forum/ebola-forum-video-archive/deans-symposium-on-ebola-crisis-context-and-response-part-4 Accessed December19, 2014 [Google Scholar]
- 9.Merck-New Link Ebola vaccine trial resumes at lower dose: Geneva hospital. Reuters January5, 2015. http://www.reuters.com/article/2015/01/05/us-health-ebola-vaccine-idUSKBN0KE0XP20150105 Accessed January29, 2015
- 10.NIH begins early human clinical trial of VSV Ebola vaccine [news release]. October22, 2014. National Institutes of Health; http://www.nih.gov/news/health/oct2014/niaid-22.htm Accessed December19, 2014 [Google Scholar]
- 11.Profectus BioSciences receives $9.5 million Department of Defense funding to manufacture trivalent VesiculoVax™-vectored vaccine to protect against all Ebola and Marburg viruses [news release]. October31, 2014. Profectus BioSciences, Inc; http://www.profectusbiosciences.net/pdfs/releases/2014%201031%20Profectus%20DoD%20Tri-V%20Ebola%20Contract.pdf Accessed December19, 2014 [Google Scholar]
- 12.Profectus BioSciences receives $8.6 million HHS contract to accelerate Ebola vaccine into human clinical studies [news release]. October22, 2014. Profectus BioSciences, Inc; http://www.profectusbiosciences.net/pdfs/releases/2014%201022%20Profectus%20Ebola%20HHS%20BARDA.pdf Accessed December19, 2014 [Google Scholar]
- 13.Bavarian Nordic announces first subject dosed with MVA-BN Filo in a Phase 1 study investigating a new prime-boost regimen of Ebola candidate vaccines [company announcement]. December4, 2014. Bavarian Nordic; http://id.bavarian-nordic.com/media/news.aspx?news=4314 Accessed December19, 2014 [Google Scholar]
- 14.Bavarian Nordic enters licensing and supply agreement with Janssen on MVA-BN Ebola vaccine. October22, 2014. Bavarian Nordic; http://id.bavarian-nordic.com/media/news.aspx?news=4241 Accessed December19, 2014 [Google Scholar]
- 15.Akst J.Ebola update: researchers gear up for efficacy trials of experimental Ebola vaccines in Africa. Scientist January12, 2015. http://www.the-scientist.com/?articles.view/articleNo/41882/title/Ebola-Update/ Accessed January29, 2015
- 16.Barry F.Ebola: which are the leading vaccine candidates? BioPharma January27, 2015. http://www.biopharma-reporter.com/Bio-Developments/Ebola-which-are-the-leading-vaccine-candidates Accessed January29, 2015
- 17.Novavax announces Ebola vaccine development program at the 8th Vaccine and ISV Conference in Philadelphia [news release]. October27, 2014. Novavax; http://www.novavax.com/download/releases/Novavax%20Announces%20Ebola%20Vaccine%20Development%20Program%20at%20the%208th%20Vaccine%20and%20ISV%20Conference%20in%20Philadelphia.pdf Accessed January29, 2015 [Google Scholar]
- 18.Ebola Vaccine Landscape [PowerPoint presentation]. US Department of Health and Human Services; January8, 2015. http://www.who.int/mediacentre/events/2015/S2.4_Robinson_ebola_MCM_landscape.pdf Accessed January29, 2015 [Google Scholar]
- 19.Ebola/Marburg: rabies vaccine protects nonhuman primates against deadly Ebola virus. National Institute of Allergy and Infectious Diseases; website. Updated July15, 2013. http://www.niaid.nih.gov/topics/ebolaMarburg/Pages/rabiesVaccebola.aspx Accessed December19, 2014 [Google Scholar]
- 20.Fact Sheet: update on the Ebola response. Official Wire; website. December2, 2014. http://www.officialwire.com/pr/fact-sheet-update-on-the-ebola-response/ Accessed December19, 2014 [Google Scholar]
- 21.About investigational TKM-Ebola therapeutic. Tekmira; website. http://www.tekmira.com/pipeline/tkm-ebola.php Accessed December19, 2014 [Google Scholar]
- 22.BioCryst announces study results for BCX4430 in a non-human primate model of Ebola virus infection [press release]. December23, 2014. BioCryst; http://investor.shareholder.com/biocryst/releasedetail.cfm?ReleaseID=888802 Accessed January29, 2015 [Google Scholar]
- 23.Caulderwood K.Chimerix Ebola drug Brincidofovir begins testing in Liberia. International Business Times January8, 2015. http://www.ibtimes.com/chimerix-ebola-drug-brincidofovir-begins-testing-liberia-1777636 Accessed January29, 2015
- 24.Experimental therapies: growing interest in the use of whole blood or plasma from recovered Ebola patients (convalescent therapies) [news release]. September26, 2014. World Health Organization; website. http://www.who.int/mediacentre/news/ebola/26-september-2014/en/ Accessed December19, 2014 [Google Scholar]
- 25.Kroll D.FDA moves on Tekmira's Ebola drug while Sarepta's sits unused. Forbes August7, 2014. http://www.forbes.com/sites/davidkroll/2014/08/07/fda-moves-on-tekmiras-ebola-drug-while-sareptas-sits-unused/ Accessed December19, 2014
- 26.Jarvis LM, Halford B. Unraveling Ebola. Chem Eng News 2014;92(48):8-15 http://cen.acs.org/articles/92/i48/Unraveling-Ebola.html Accessed December19, 2014
- 27.Oestereich L, Ludtke A, Wurr S, Rieger T, Muñoz-Fontela C, Günther S. Successful treatment of advanced Ebola virus infection with T-705 (favipiravir) in a small animal model. Antiviral Res 2014;105:17-21 [DOI] [PubMed] [Google Scholar]
- 28.Understanding expanded access/compassionate use. US Food and Drug Administration; website. Updated October29, 2014. http://www.fda.gov/forpatients/other/expandedaccess/default.htm Accessed December19, 2014 [Google Scholar]
- 29.DOD helps fight Ebola in West Africa. Operation United Assistance. US Department of Defense; website. October2014. http://www.defense.gov/home/features/2014/1014_ebola/ Accessed December18, 2014 [Google Scholar]
- 30.H.R. 83, 113th Cong. (2014). https://www.congress.gov/bill/113th-congress/house-bill/83/all-info Accessed December18, 2014