Study of DITPA in Patients With Congestive Heart Failure

Rationale: Congestive heart failure (CHF) is a major public health problem associated with significant morbidity and mortality in patients with New York Heart Association (NYHA) class III or IV disease. Multiple studies have identified a particularly high-risk group of patients who have reduced thyroid hormone activity, specifically, low serum triiodothyronine (T3) levels. This group represents approximately 30% of patients with NYHA class III or IV disease and has significantly higher mortality rates than those with normal T3. DITPA (3,5-diiodothyropropionic acid) is an analogue of naturally occurring thyroid hormone (T3) that has been specifically designed to improve cardiac performance with a lower potential for tachycardia in CHF patients. Although structurally similar to T3, DITPA has a propionic acid side chain and lacks an iodine at the 3' position of the outer phenolic ring. While DITPA binds to the same thyroid hormone receptors as T3, binding affinities are significantly less, suggesting partial agonistic actions. Preclinical studies with DITPA have supported a rationale for its use in patients with CHF. Primary objective: To assess the safety and tolerability of DITPA in patients with NYHA class III/IV CHF and low serum T3. Secondary Objective: To obtain preliminary evidence of the efficacy of DITPA in patients with NYHA class III/IV CHF and low serum T3 Design: The multi-center, randomized, double-blind, placebo-controlled study is designed to evaluate the safety and tolerability of DITPA in patients with NYHA class III or IV CHF who have low levels of serum T3 with normal levels of thyroid stimulating hormone (TSH). One hundred and fifty patients at approximately 35 centers in the U.S. will be randomized to 1 of 3 treatment groups in a 1:1:1 ratio (i.e., 50 patients per treatment group): * DITPA at 180 mg/day (90 mg twice a day \[BID\], orally) * DITPA at 360 mg/day (180 mg BID, orally) * Placebo BID, orally