UPDATE 1-US health officials say Ebola treatment trial to start soon in Liberia

(Adds details on trials)

Jan 22 (Reuters) - U.S. health officials said on Thursdaythat they are planning to start larger, decisive clinical trialsin Liberia in the next two weeks to determine if two new Ebolatreatments under development are safe and effective.

One of the treatments is being developed by GlaxoSmithKline and another by Newlink Genetics Corp with Merck& Co.

The U.S. government and leading drugmakers have acceleratedtheir efforts to bring a vaccine or treatment to market sincethe Ebola outbreak reached crisis proportions in West Africalast year. That includes speeding to human trials treatmentsthat had only been tested in non-human primates.

The treatments are advancing even as the World HealthOrganization said the epidemic in West Africa appears to beebbing.

There have been 21,724 cases of Ebola reported in ninecountries in the past year since the epidemic began in Guinea,including 8,641 deaths, according to the latest WHO figures.

The officials, speaking on a conference call, also said thatthey expect to soon start phase 1 and phase 2 clinical trials -an earlier stage than the trials for the other two treatments -of the ZMapp Ebola virus treatment that is being developed byprivately held Mapp Biopharmaceutical Inc.

They said they believe they have produced enough ZMapp tosupply the trials, which are awaiting approval from the U.S.Food and Drug Administration and will likely start two to threeweeks later.

Dr. Robin Robinson, Director of the U.S. government'sBiomedical Advanced Research and Development Authority, said itexpects to have thousands of doses of the ZMapp drug availableby the end of the year for commercial use if the treatment isproved effective in the trials.

In Liberia, about 27,000 people are expected to take part inthe trial for the treatments from GlaxoSmithKline, Merck andNewLink. In Sierra Leone, where the officials said they are alsoconsidering moving forward with a trial, they are targetinghealthcare workers and expect to include about 6,000 people.Sierra Leone has yet to decide which treatment would be used inthat trial, the officials said. (Reporting by Bill Berkrot and Caroline Humer; editing byAndrew Hay and Christian Plumb)