The purpose of this preliminary study is to test the hypothesis that administration of minocycline to humans with moderate and severe TBI is both safe and feasible in the acute post-injury setting, and to characterize its disposition and effects on biomarkers of traumatic CNS injury in a Phase IIa trial. The data collected will serve as the basis for a larger Phase IIb clinical trial in a randomized placebo-controlled parallel group design, to investigate further its potential safety and efficacy as a therapeutic agent for severe human TBI.
Tetracycline derivatives, including doxycycline and minocycline, have been shown to be neuroprotective when given after traumatic brain injury (TBI) and ischemia in rodents. In particular, reduced lesion volume and improved neurological outcome have been demonstrated following minocycline treatment of TBI. The proposed mechanism for these observations is multifactorial, and includes inhibition of microglial activation, caspase-mediated apoptosis, and the excitotoxic N-methyl-D-aspartic acid (NMDA) pathway. Because comparable inflammatory, excitotoxic and apoptotic pathways have also been implicated in human TBI, we hypothesize that administration of minocycline will confer neuroprotection after moderate to severe TBI in that milieu as well, with the potential for significant clinical benefit. Minocycline is highly lipophilic, and thus penetrates the human central nervous system (CNS). In addition, it has been shown to be safe when used in non-traumatic human neurological disorders.