According to the US National Academy of Sciences Institute of Medicine, "Chronic fatigue syndrome is a disease characterized by profound fatigue, cognitive dysfunction, sleep abnormalities, autonomic manifestations, pain, and other symptoms that are made worse by exertion of any sort. CFS can severely impair patients’ ability to conduct their normal lives." In October 2007, Hemispherx BioPharma submitted their first new drug application (NDA) to the FDA for rintatolimod to treat CFS. In December 2007, the agency deemed the application incomplete, citing deficiencies including lack of dose ranging, statistical analysis plans inconsistent with protocols, database discrepancies, and lack of clinical pharmacology and carcinogenicity data. In early 2009, Hemispherx again submitted rintatolimod for FDA approval for CFS treatment. The FDA scheduled their decision for May 25th of that year and twice postponed. The company received a complete response letter from the agency on rintatolimod's NDA in December 2009, requesting further data.