A phase I clinical trial of the fast-tracked Ebola vaccine VSV-ZEBOV has been halted in Switzerland because some trial participants developed mild joint pain after receiving the injection.
Some of the 59 volunteers who received the experimental vaccine experienced fever and muscle pain in the hours and days after the vaccine was administered. It was after four volunteers reported unanticipated joint pain in hands and feet 10–15 days after receiving the vaccine that prompted the University Hospitals of Geneva (HUG) to halt the trial as a precautionary measure.
The trial, which began on 10 November 2014, is a collaboration between HUG and the World Health Organization. It will resume on 5 January 2015 if the symptoms prove to be benign and temporary, says HUG in a statement. The available time will allow HUG to gather more information and share it with the other teams that are testing the same vaccine.
It is not thought that this reaction has been noted in patients receiving the vaccine at other study sites; trials of VSV-ZEBOV are underway in the United States, Canada, Germany and Gabon and due to start soon in Kenya. The WHO has said The Data and Safety Monitoring Board has recommended that vaccinations can continue at doses lower than those used in the trial in Geneva to date.
HUG says that it plans to recruit up to of 15 volunteers per week when the trial resumes in order to ensure optimum monitoring conditions.
VSV-ZEBOV is being developed by Merck & Co, headquartered in New Jersey, after it gained exclusive rights to the vaccine from Iowa-based NewLink Genetics in November 2014.
VSV-ZEBOV was originally developed by the Public Health Agency of Canada and has been fast-tracked for clinical development under a World Health Organization programme. Pending results of the phase I safety studies, the US National Institutes of Health plans to initiate a large Phase III study of VSV-ZEBOV and another investigational Ebola vaccine co-developed by the National Institute of Allergy and Infectious Diseases and GlaxoSmithKline.