Lomitapide and mipomersen: novel lipid-lowering agents for the management of familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disorder caused primarily by mutations in the low-density lipoprotein receptor gene. Familial hypercholesterolemia is characterized by exceedingly high levels of low-density lipoprotein cholesterol (LDL-C) and subsequent premature coronary heart disease. Homozygous FH (HoFH) is less prevalent, but more severe, than heterozygous FH. Current treatment options include dietary therapy, lipid-lowering agents (eg, statins), and/or LDL-C apheresis. PURPOSE: Despite the available treatment options, patients with FH rarely attain treatment goals. This review will focus on 2 novel agents, lomitapide and mipomersen, with recently approved US Food and Drug Administration (FDA) labeling for use in patients with HoFH. CONCLUSIONS: Lomitapide and mipomersen are 2 agents with novel mechanisms of action and the ability to significantly lower LDL-C, apolipoprotein B, and non-high-density lipoprotein cholesterol levels. A black box warning exists for lomitapide and mipomersen regarding the risk for transaminase elevations and hepatic steatosis. Furthermore, these agents are currently restricted for use only in patients with HoFH and have been required by the FDA to participate in a Risk Evaluation and Mitigation Strategy. CLINICAL IMPLICATIONS: These new agents offer additional treatment options for clinicians managing patients with HoFH, but it remains uncertain whether lomitapide and mipomersen will gain FDA approval for use in patients with heterozygous FH or in the general population. Cost and concern for the risk for hepatotoxicity will remain limiting factors to these agents being more widely used.

Toll-like receptor 4 modulates skeletal muscle substrate metabolism.

Toll-like receptor 4 (TLR4), a protein integral to innate immunity, is elevated in skeletal muscle of obese and type 2 diabetic humans and has been implicated in the development of lipid-induced insulin resistance. The purpose of this study was to examine the role of TLR4 as a modulator of basal (non-insulin-stimulated) substrate metabolism in skeletal muscle with the hypothesis that its activation would result in reduced fatty acid oxidation and increased partitioning of fatty acids toward neutral lipid storage. Human skeletal muscle, rodent skeletal muscle, and skeletal muscle cell cultures were employed to study the functional consequences of TLR4 activation on glucose and fatty acid metabolism. Herein, we demonstrate that activation of TLR4 with low (metabolic endotoxemia) and high (septic conditions) doses of LPS results in increased glucose utilization and reduced fatty acid oxidation in skeletal muscle and that these changes in metabolism in vivo occur in concert with increased circulating triglycerides. Moreover, animals with a loss of TLR4 function possess increased oxidative capacity in skeletal muscle and present with lower fasting levels of triglycerides and nonesterified free fatty acids. Evidence is also presented to suggest that these changes in substrate metabolism under metabolic endotoxemic conditions are independent of skeletal muscle-derived proinflammatory cytokine production. This report illustrates that skeletal muscle is a target for circulating endotoxin and may provide critical insight into the link between a proinflammatory state and dysregulated metabolism as observed with obesity, type 2 diabetes, and metabolic syndrome.

The US Food and Drug Administration's Perspective on the New Antipsychotic Pimavanserin.

OBJECTIVE: To summarize the US Food and Drug Administration's (FDA's) review of the safety and effectiveness for pimavanserin, an atypical antipsychotic, for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis. We describe the regulatory and clinical issues important to the FDA's approval of this New Drug Application, with special focus on the risk-benefit balance. We also describe a new labeling feature that presents additional efficacy data to clinicians. DATA SOURCES: Data sets for all relevant clinical trials of pimavanserin and the Applicant's and FDA's analyses of these data were considered in this review. Data were available from 616 patients with Parkinson's disease with hallucinations and delusions who received at least 1 dose of pimavanserin, with a total exposure of 825 patient-years in the Parkinson's disease psychosis population. RESULTS: Pimavanserin 34 mg/d was effective in treating hallucinations and delusions associated with Parkinson's disease. In the Applicant's single pivotal trial, 80.5% of pimavanserin patients experienced at least some improvement in symptoms compared to 58.1% of patients taking placebo. Pimavanserin did not worsen motor function, an adverse effect commonly observed with other antipsychotics, probably because of a lack of consequential dopamine binding. CONCLUSIONS: Pimavanserin is the only FDA-approved treatment for the hallucinations and delusions seen in patients with psychosis of Parkinson's disease. Although pimavanserin appears to have a pharmacologic mechanism that is different from other atypical antipsychotics, concern remained that the increased risk of death seen with antipsychotic use in elderly demented patients, and described in all approved antipsychotic labels, would also occur with pimavanserin. Pimavanserin bears the same boxed warning about the risk of death associated with antipsychotic use in elderly patients with dementia.