SIGA Technologies Incorporated, New York, New York, has signed a contract with the Biomedical Advanced Research and Development Authority of the United States Department of Health and Human Services (HHS) to deliver two million courses of its smallpox antiviral, ST-246(R), to the strategic national stockpile. The contract award is worth $433 million and includes options that would raise the contract's total value to approximately $2.8 billion, if exercised. ST-246(R) is an oral therapeutic agent active against orthopoxviruses, including smallpox. While no longer present naturally in the environment, smallpox is considered a bioterrorism threat, and there is currently no FDA-approved treatment for symptomatic individuals. ST-246(R) works by blocking the ability of the virus to spread to other cells, preventing it from causing disease. The FDA has designated ST-246(R) for "fast-track" status, creating a path for expedited FDA review and eventual regulatory approval.