? ? Traumatic brain injury (TBI) is a major cause of premature death and disability worldwide. With the possible functional outcomes. We recently completed an NINDS-funded, Phase l/lla double-blinded, randomized placebo-controlled pilot clinical trial examining the pharmacokinetics, safety, and activity of progesterone, a steroid found to have powerful neuroprotective properties in multiple different animal models of brain injury. Based on encouraging results, we propose to conduct a phase III clinical trial to determine the efficacy and confirm safety of this treatment in adults with moderate to severe TBI. ? Our primary objective is to determine the effectiveness of intravenous progesterone initiated within 4 hours of injury and administered for 72 hours, followed by an additional 24 hour taper, as compared to placebo at improving functional outcome in patients with moderate to severe traumatic brain injury. The primary functional outcome will be determined by Glasgow Outcome Scale - Enhanced (GOSE) measured at 6 months after injury. Secondary objectives are to examine the effects of progesterone versus placebo on mortality, intracranial pressure, alternative measures of functional neurological outcome, on rates of adverse events, and examine the effectiveness in 5 clinical subgroups in patients with moderate to severe TBI. In order to proceed towards the Phase III clinical trial, we are submitting a clinical trial planning grant. The specific objectives of the planning grant are to complete a Manual of Operations; identify, recruit and certify participating centers; assess each candidate center's ability to enroll eligible patients; develop a MCCT data management plan; complete study materials and generate study forms; prepare training schedules and materials; establish committees and organizational chart; prepare budgets and cooperative agreements: develop a model IRB protocol, work with local IRBs to implement Exception from Consent; and obtain FDA IND final approval for intravenous use of progesterone to treat acutely brain-injured adults with an Exception from Informed Consent. ? ? ?