Experimental Ebola drug trial is called off

Promising possible treatment a failure, developer reports.

In a setback for efforts to treat Ebola,an experimental drug that researchers had considered one of the most promising potential treatments has not worked in patients in Sierra Leone,the drug’s developer said Friday.

T he company,T ekmira Pharmaceuticals,said in a news release that enrollment in a clinical trial testing its drug had been ended because the drug was “not likely to demonstrate an overall therapeutic benefit,” even if the trial had continued.

T he company did not provide actual results, saying the data were being analyzed and full results would be made available later.

T he drug,called TK M - Ebola-G uinea,uses a technique called R NA interference to block the action of certain genes of the Ebola virus.It was considered one of the most promising treatments because it had worked in monkeys deliberately infected with the virus.

D r.Peter H orby of the University of O xford,the lead investigator in the trial,said in an email that the drug “has not demonstrated an overall therapeutic benefit,” but that more time was needed to better interpret the results.

T he study,which was paid for by the Wellcome T rust,a B ritish charity,did not have a control group of patients getting a placebo or a different drug.A ll the patients received the drug.T he effectiveness of the drug was judged by comparing the treated patients with others in Sierra Leone who did not get the drug.

U.S.health officials have criticized the lack of a control group as a weakness that would make it harder to see if drugs were safe and effective. B ut other authorities,including the ones involved in this study,said it would be unethical to offer patients a placebo and that patients would be less likely to enroll in a study if there were a chance they would get a placebo.