TNF and Glucocorticoid Antagonist for GWI Associated Multi-symptom Disease Homeostasis Reset

This is a study in male Veterans 45-70 years of age who meet the modified Kansas and Centers for Disease Control and Prevention (CDC) criteria for GWI (Gulf War Illness) and have high physiologic stress. This phase I single-site, open-label, two-arm study will focus on optimizing the dosage of a sequential etanercept-mifepristone intervention for GWI. Twenty participants will be assessed at baseline, 6, 12, 13, 16 and 24 weeks. The investigators will use systems biology methods to perform computational modelling of physiological responses to supervised maximal exercise challenge studies on a fitness bicycle at baseline and 24 weeks. These analyses will assess the impact of the treatment on homeostatic networks: the changes in levels of physiological parameters and the changes in inter-correlations among the measured parameters (e.g., cytokines), cross-sectionally and over time. Participants will also undergo subjective assessments of functional health, symptom severity, pain, fatigue, and cognition at baseline, 6, 12, 13, 16, and 24 weeks. Participants will be observed through the treatment period and for 3 months after completion to assess immediate effects and durability of the response. The results of this phase I study will be compared to those from an existing short-duration study to identify the optimal duration and dosage for use in a future phase II study.