Safety and efficacy of a soluble P75 tumor necrosis factor receptor (Enbrel, etanercept) in patients with advanced heart failure

Background - Although previous studies suggested that TNF may contribute to heart failure progression, it is unclear whether antagonizing TNF is beneficial in heart failure patients. Methods and Results - Eighteen NYHA class HI heart failure patients were randomized into a double-blind dose- escalation study to examine the safety and potential efficacy of etanercept, a specific TNF antagonist (Enbrel). Patients received placebo (6 patients) or an escalating dose (1, 4, or 10 mg/m²) of etanercept (12 patients) given as a single intravenous infusion. Safety parameters and patient functional status were assessed at baseline and at days 1, 2, 7, and l4. There were no significant side effects or clinically significant changes in laboratory indices. There was, however, a decrease in TNF bioactivity and a significant overall increase in quality-of-life scores, 6-minute walk distance, and ejection fraction in the cohort that received 4 or 10 mg/m² of etanercept; there was no significant change in these parameters in the placebo group. Conclusions - A single intravenous infusion of etanercept was safe and well tolerated in patients with NYHA class III heart failure. These studies provide provisional evidence that suggests that etanercept is sufficient to lower levels of biologically active TNF and may lead to improvement in the functional status of patients with heart failure.