A select number of patients infected with the coronavirus will start receiving an experimental drug that researchers hope could stop the virus in its tracks. President Donald Trump told the nation Thursday in his daily briefing that he was fast-tracking trials of the drug, Remdesivir.

"It seems to have a very good result having to do with this virus," Trump said about Remdesivir, produced by the California-based biotechnology company Gilead.

UCLA Medical Center is one of several centers around the country involved in the clinical trials starting today, involving about 1000 patients.

Dr. Otto Yang of UCLA Medical Center, the principal investigator on the study, said only selected patients will start receiving Remdesivir today, administered by daily injection.

"There are very strict criteria. They have to be adults. They have to be ill enough to be admitted to the hospital and show signs of COVID-19 that are significant clinically," Yang said.

Remdesivir is already being tested experimentally on patients in China and Washington state in the hope it stops the coronavirus from replicating in the body. It has also shown promise fighting viruses in research on animals.

"Those are animal models and that does not always translate to humans," Yang said.

The trials at UCLA are what's known as a "Double-Blind Placebo Study." That means half the patients get Remdesivir and half get a placebo. Yang said conclusive results about the effectiveness of the drug will take weeks or months to gather.

"I think we should be very careful about being too optimistic and we should be hopeful, but we really need to wait and see what the results show," Yang said.