Shares in Tekmira have taken a downturn after it emerged that its experimental Ebola vaccine was unlikely to hit efficacy goals in a mid-stage trial.

The Vancouver, Canada-based group said it has stopped enrolment in the Phase II, Sierra Leone-based trial after a predefined statistical endpoint indicated that there was not likely to be an overall therapeutic benefit from its jab.

However, “final conclusions on the efficacy and tolerability of the drug must await full analysis of the data,” noted Peter Horby, Associate Professor of Infectious Diseases and Global Health, University of Oxford, Chief Investigator on the study.

Data analysis is ongoing and full results will be made available as soon as possible, the firm said.

Tekmira’s RNAi therapeutic - designed to switch off certain genes responsible for the virus’ proliferation - was being tested by Oxford University researchers against the Ebola-Guinea strain behind the current outbreak in Africa, with funding help from the UK’s Medical Research Council.