Peroxisome proliferator–activated receptors (PPARs) are nuclear transcription factors that modulate gene expression. Therapeutic agents targeting 2 distinct families of PPARs (α and γ) have been introduced in the United States. The first dual-PPAR agonist, muraglitazar, was reviewed by a US Food and Drug Administration (FDA) advisory committee on September 9, 2005, resulting in a vote of 8:1 recommending approval for its use in controlling blood glucose levels in patients with type 2 diabetes.
To evaluate the incidence of death, myocardial infarction (MI), stroke, congestive heart failure (CHF), and transient ischemic attack (TIA) in diabetic patients treated with muraglitazar compared with controls.
Design, Setting, and Participants
The source material for this analysis consisted of documents about phase 2 and 3 clinical trials released under public disclosure laws for the FDA advisory committee meeting. All reviewed trials were prospective, randomized, double-blind, multicenter studies enrolling patients with type 2 diabetes and hemoglobin A1c levels between 7% and 10%. Patients (N = 3725) were randomized to receive differing doses of muraglitazar, pioglitazone, or placebo as monotherapy or in combination with metformin or glyburide in trials ranging from 24 to 104 weeks.
Main Outcome Measures
The primary outcome was the incidence of death, nonfatal MI, or nonfatal stroke. A more comprehensive composite outcome included these events plus the incidence of CHF and TIA.
In the muraglitazar-treated patients, death, MI, or stroke occurred in 35 of 2374 (1.47%) patients compared with 9 of 1351 (0.67%) patients in the combined placebo and pioglitazone treatment groups (controls) (relative risk [RR], 2.23; 95% confidence interval [CI], 1.07-4.66; P = .03). For the more comprehensive outcome measure that included TIA and CHF, the incidence was 50 of 2374 (2.11%) for muraglitazar compared with 11 of 1351 (0.81%) for controls (RR, 2.62; 95% CI, 1.36-5.05; P = .004). Relative risks for each of the individual components of the composite end point exceeded 2.1 but were not statistically significant. Incidence of adjudicated CHF was 13 of 2374 (0.55%) muraglitazar-treated patients and 1 of 1351 controls (0.07%) (RR, 7.43; 95% CI, 0.97-56.8; P = .053).
Compared with placebo or pioglitazone, muraglitazar was associated with an excess incidence of the composite end point of death, major adverse cardiovascular events (MI, stroke, TIA), and CHF. This agent should not be approved to treat diabetes based on laboratory end points until safety is documented in a dedicated cardiovascular events trial.