The Biomarkers in the Hyperbaric Oxygen Brain Injury Treatment Trial (BioHOBIT)

There are no therapeutic agents that have been shown to improve outcomes from severe traumatic brain injury (TBI). Critical barriers to progress in developing treatments for severe TBI are the lack of: 1) monitoring biomarkers for assessing individual patient response to treatment; 2) predictive biomarkers for identifying patients likely to benefit from a promising intervention. Currently, clinical examination remains the fundamental tool for monitoring severe TBI patients and for subject selection in clinical trials. However, these patients are typically intubated and sedated, limiting the utility of clinical examinations. Validated monitoring and predictive biomarkers will allow titration of the dose of promising therapeutics to individual subject response, as well as make clinical trials more efficient by enabling the enrollment of subjects likely to benefit. Glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL) and high sensitivity c-reactive protein (hsCRP) are promising biomarkers that may be useful as 1) monitoring biomarkers; 2) predictive biomarkers in severe TBI trials. Although the biological rationale supporting their use is strong, significant knowledge gaps remain. To address these gaps in knowledge, we propose an ancillary observational study leveraging an ongoing severe TBI clinical trial that is not funded to collect biospecimen. The Hyperbaric Oxygen in Brain Injury Treatment (HOBIT) trial, a phase II randomized control clinical trial that seeks to determine the dose of hyperbaric oxygen therapy (HBOT) that that has the highest likelihood of demonstrating efficacy in a phase III trial. The proposed study will: 1) validate the accuracy of candidate monitoring biomarkers for predicting clinical outcome; 2) determine the treatment effect of different doses of HBOT on candidate monitoring biomarkers; and 3) determine whether there is a biomarker defined subset of severe TBI that responds favorably to HBOT. This proposal will: 1) inform a go/no-go decision for a phase III trial of HBOT by providing adjunctive evidence of the effect of HBOT on key biological pathways through which HBOT is hypothesized to affect outcome; 2) provide evidence to support further study of the first monitoring biomarkers of severe TBI; 3) increase the likelihood of success of a phase III trial by identifying the sub-population of severe TBI likely to benefit from HBOT; 4) create a repository of TBI biospecimen which may be accessed by other investigators.