Chimerix Inc., of Research Triangle Park, N.C., started enrolling patients in an open-label study of CMX001, in development for dual use as a broad-spectrum antiviral against life-threatening viral infections in immunocompromised patients and as a medical countermeasure in the event of a smallpox outbreak. The primary objective of the study is to provide CMX001 to patients with immediately life-threatening or serious disease caused by any of 12 different viral infections resulting from dsDNA viruses.