A San Antonio medical research facility is one of six centers nationwide chosen for the trial of a new drug treatment for coronavirus patients. The South Texas Allergy & Asthma Medical Professionals research center is making the anticoagulant Xarelto available free of charge to thousands of patients who have mild symptoms and underlying health conditions that put them in a high-risk category. Patients meeting these criteria can find out more about the 21-day trial at the web site staampallergy.com.