Liberia moves a step closer to Ebola vaccine trials

In a move that puts West Africa's Ebola outbreak region closer to key vaccine trials, GlaxoSmithKline (GSK) announced today that it expects the first batch of vaccine to arrive today in Liberia, where a large-scale trial will begin soon.

The vaccine is one of two slated for large efficacy trials over the next couple months. The vaccine, called ChAD3, uses a modified chimpanzee adenovirus and was developed by the US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), and GSK.

A second vaccine developed by Canadian researchers and licensed by NewLink Genetics and Merck is also nearing clinical trials in the outbreak region. That vaccine uses an Ebola virus protein spliced into a vesicular stomatitis virus (VSV-EBOV). NIAID Director Anthony Fauci, MD, said the NIH is partnering with Liberia's government to test both vaccines, with trials to launch in a few weeks, USA Today reported yesterday.

The estimates of the trial launch are roughly in line with a late January estimate made by World Health Organization (WHO) experts after a meeting earlier this month to discuss phase 1 trial developments and sketch out the next research phases.  They also projected that trials would launch in Guinea and Sierra Leone sometime in February.

Trial details, possible obstacles

GSK said in a statement that the shipment contains an initial 300 vials of the vaccine, which is currently being tested in five small phase 1 studies in the United Kingdom, United States, Switzerland, and Mali. The studies involve different doses, and so far initial data show that that the vaccine has an acceptable safety profile.

The company said it has selected a dosage level for the upcoming larger-scale efficacy studies, but its statement did not specify the dosage that will be tested. The clinical trial planned for Liberia would involve up to 30,000 people, one-third of whom would get the ChAD3 vaccine. Researchers will compare it against a control vaccine to gauge if the immune response seen in phase 1 trials protects against Ebola in an outbreak setting.

Among the study volunteers will be frontline health workers, GSK said.

The number of Ebola infections, however, has fallen rapidly in Liberia over the past several weeks and is now dropping quickly in Guinea and Sierra Leone, as well, leading some experts to question if the conditions will delay the phase 3 trials or even make them impossible to conduct.

Researchers who are preparing to conduct a convalescent serum trial in Liberia are airing similar concerns. They said they might not be able to proceed or may need to move the trial to Sierra Leone, where cases are declining but are still higher than in the other two outbreak countries, Bloomberg News reported yesterday, citing two unnamed people who are familiar with the project.

Fauci said if scientists aren't able to enroll enough volunteers in Liberia they may reach out to Sierra Leone, according to the USA Today report. He said even if conditions aren't optimal, the trials will still yield useful information about safety and immune response.

Fauci noted that if the scientists can't gather enough data, the companies can apply for approval through a process for highly lethal diseases. (The US Food and Drug Administration's "animal rule" allows lab animal data to be used to show efficacy in the event human trials aren't feasible.)

Pending regulatory approval, the clinical trial will launch in Liberia in the coming weeks with more vaccine shipments to follow, GSK said, adding that large phase 2 studies are slated to launch at the same time in West African countries that weren't hit by Ebola.

Outbreak region update

With a small number of Ebola cases and deaths continuing to be reported in the three hardest hit countries, the total in the region has grown to 21,797 infections, along with 8,675 deaths, the World Health Organization (WHO) reported today.

The most recent total reflects an increase of 38 infections and 7 fatalities compared with yesterday's WHO total. Numbers include cases reported to Jan 20 for all three countries, and all of the newly reported cases are in Sierra Leone. For the deaths, 6 are from Sierra Leone and 1 is from Guinea.

In other outbreak region developments, the United Nations Mission for Ebola Emergency Response (UNMEER) said today that Liberia's health ministry, the UN Children's Fund, and other partners are addressing recent outbreaks in Liberia's Tewor district in Grand Cape Mount County with a "mop-up" campaign that targets 30,000 people living in 6,600 households. The efforts will focus on disease prevention, rapid reporting and isolation, safe burials, and reducing stigmatization.

UNMEER also reported that community resistance to safe burials and suspicion about burial teams are continuing in many parts of Liberia, an issue that it says will continue to be addressed in the next phase of the response. UNMEER said it and county authorities will follow up on recent burials that occurred in three locations in Nimba County.

See also:

Jan 23 GSK press release

Jan 22 USA Today story

Jan 9 CIDRAP News story "WHO experts chart next steps for Ebola vaccine trial"

Jan 22 Bloomberg News story

Jan 23 WHO update

Jan 23 UNMEER update

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