NIH trial success suggests a new treatment option for older, sicker patients.   Half of patients in a trial have safely stopped immunosuppressant medication following a modified blood stem-cell transplant for severe sickle cell disease, according to a study in the July 1 issue of the Journal of the American Medical Association External Web Site Policy. The trial was conducted at the National Institutes of Health’s Clinical Center in Bethesda, Maryland, by researchers from NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the National Heart, Lung, and Blood Institute.