Gilead has revealed it is working on an experimental anti-viral for Ebola, after it emerged this week that nurse Pauline Cafferkey elected to receive the drug at London’s Royal Free hospital following her re-admission with late complications of the disease.

The company confirmed that it has fulfilled a request for compassionate access to GS-5734, a novel nucleotide analogue in development for the potential treatment of Ebola, discovered as part of its programme to screen compounds in its libraries for activity against a range of potential emerging viruses.

In animal studies conducted treatment initiated on day three post-infection with Ebola virus resulted in 100% survival of monkeys, Gilead said, also nothing that a Phase I clinical trial in healthy human volunteers is now underway to determine the safety, tolerability and pharmacokinetics of the drug.

Ms Cafferkey contracted Ebola nine months ago while working Sierra Leone and initially overcame the virus, but was readmitted to hospital earlier this month after developing viral meningitis caused by her original infection, an unusual and late complication of the illness. Doctors say her condition has now significantly improved.

“I am hopeful Pauline will make a full recovery – maybe it will be with the help of this anti-viral drug, maybe it will be down to her own immune system. Over time I anticipate that the virus will be eradicated from her completely,” said infectious disease consultant Michael Jacobs.

“It is very encouraging to hear that the patient in question is doing better and is no longer in critical condition,” said Norbert Bischofberger, Gilead’s chief scientific officer. “We recognize the urgent need for treatments to address Ebola and we are working with collaborators to advance development of GS-5734 as quickly as possible”.