Coronavirus patients around the world are rushing to join studies of an experimental drug that showed promise against some similar viruses in the past. Interest in the drug remdesivir has been so great that the U.S. National Institutes of Health is boosting the size of its study, which has nearly reached its initial goal just a few weeks after starting. Drugmaker Gilead Sciences is quickly enrolling patients in its own studies, too. The drug is designed to interfere with an enzyme that reproduces viral genetic material. Results from the first tests of it in China are expected later this month.