One of the report authors, Dr Robert Clarke, from the Clinical TrialService Unit at the University of Oxford, said that the findings were "reassuring".
On Sept. 15, Rory Collins, the head of the Clinical TrialService Unit at Oxford, was called by Merck and told of the SEAS result, according to the letter.
The trialservice will cover three rural general hospitals and 13 community hospitals within Argyll and Bute, Lochaber, Skye and Lochalsh, Wigtown, Western Isles, Arran, Cumbrae and Kinloch Rannoch.