Ebola virus virion

Merck and NewLink Genetics have initiated the third, late-stage, clinical trial of their Ebola vaccine candidate, rVSV-ZEBOV-GP (V920), in Sierra Leone.

Originally developed by the Public Health Agency of Canada’s National Microbiology Laboratory , the Ebola vaccine candidate was licenced to NewLink Genetics in 2010.

In November 2014, Merck and NewLink Genetics entered into an exclusive licencing and collaboration agreement for the investigational Ebola vaccine.

The Phase II/ III safety and effectiveness trial (STRIVE) will include 6,000 health and other frontline workers and is being led by the Sierra Leone College of Medicine and Allied Health Sciences, Sierra Leone Ministry of Health and Sanitation, and the US Centers for Disease Control and Prevention (CDC).

Merck Vaccines chief public health and science officer Mark Feinberg said: "Fighting Ebola remains a global health priority, and Merck is committed to advancing the development of our and NewLink’s vaccine candidate as part of our overall response to the crisis."

The rVSV-ZEBOV-GP vaccine candidate is currently included in three large-scale clinical trials currently underway in West Africa.

Apart from the trial in Sierra Leone, other trials include the Partnership for Research on Ebola Vaccines in Liberia (PREVAIL) and a Phase III trial in Guinea.

PREVAIL was designed to enrol around 27,000 healthy men and women aged 18 years and older and it is led by a Liberia-US clinical research partnership and sponsored by the National Institute of Allergy and Infectious Diseases (NIAID).

The randomised, controlled Phase II/III PREVAIL trial will evaluate safety and efficacy, involves rVSV-ZEBOV-GP and another experimental Ebola vaccine.

The World Health Organization (WHO), the Health Ministry of Guinea, Médecins sans Frontières (MSF), Epicentre and The Norwegian Institute of Public Health have started a safety and effectiveness Phase III trial in Guinea which will evaluate rVSV-ZEBOV-GP.

Image: Electron micrograph of an Ebola virus virion. Photo: courtesy of CDC/Cynthia Goldsmith.