 Open-label studies are typically used when the controlled trial has ended and treatment is continued so that the subjects and the controls may continue to receive the investigational drug until marketing approval is obtained.Hemispherx management had missed several target deadlines for new drug application (NDA) filing in the past, including the end of 2005, the third quarter of 2006, and the first quarter of the year 2007.In October 2007, the US Food and Drug Administration (FDA) Ampligen NDA was filed.