Amgen has filed its closely watched PCSK9 inhibitor Repatha (evolocumab) in Japan for the treatment of high cholesterol.
Repatha is an investigational fully human monoclonal antibody that inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9), a protein that reduces the liver’s ability to remove low-density lipoprotein cholesterol (LDL-C), or ‘bad’ cholesterol, from the blood.
Evolocumab (also known as compound number AMG-145 or AMG145) is a monoclonal antibody designed for the treatment of hyperlipidemia. Evolocumab is a fully human monoclonal antibody that inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9).
Evolocumab, being developed by Amgen scientists, is designed to bind to PCSK9 and inhibit PCSK9 from binding to LDL receptors on the liver surface. In the absence of PCSK9, there are more LDL receptors on the surface of the liver to remove LDL-C from the blood.
Two trials have been in progress as at mid-2014:
On 23 January 2014 Amgen announced that the Phase 3 GAUSS-2 (Goal Achievement After Utilizing an Anti-PCSK9 Antibody in Statin Intolerant Subjects-2) trial evaluating evolocumab in patients with high cholesterol who cannot tolerate statins met its co-primary endpoints: the percent reduction from baseline in low-density lipoprotein cholesterol (LDL-C) at week 12 and the mean percent reduction from baseline in LDL-C at weeks 10 and 12. The mean percent reductions in LDL-C, or “bad” cholesterol, compared to ezetimibe were consistent with results observed in the Phase 2 GAUSS study.
The GAUSS-2 trial evaluated safety, tolerability and efficacy of evolocumab in 307 patients with high cholesterol who could not tolerate effective doses of at least two different statins due to muscle-related side effects. Patients were randomly assigned to one of four treatment groups: subcutaneous evolocumab 140 mg every two weeks and oral placebo daily; subcutaneous evolocumab 420 mg monthly and oral placebo daily; subcutaneous placebo every two weeks and oral ezetimibe 10 mg daily; or subcutaneous placebo monthly and oral ezetimibe 10 mg daily.
Safety was generally balanced across treatment groups. The most common adverse events (> 5 percent in evolocumab combined group) were headache (7.8 percent evolocumab; 8.8 percent ezetimibe), myalgia (7.8 percent evolocumab; 17.6 percent ezetimibe), pain in extremity (6.8 percent evolocumab; 1.0 percent ezetimibe), and muscle spasms (6.3 percent evolocumab; 3.9 percent ezetimibe).
Cholesterol-lowering treatment with a statin as part of follow-up care can help reduce a patient’s risk after myocardial infarction, ischaemic stroke or TIA.
The FOURIER Phase 3 clinical study http://www.fourierstudy.com/ seeks to find out whether lowering cholesterol by an additional 50% might reduce this risk even further. Several sites in the UK are part of this very large clinical study, lasting up to five years, and it is hoped that the study will help guide future clinical practice.
Evolocumab (also formerly known as AMG145, from Amgen) binds to PCSK9, a natural protein produced by the liver. By binding to PCSK9, evolocumab allows the LDL receptor (a protein present in the liver) to move LDL-cholesterol out of the bloodstream more efficiently. This study is designed to see whether treatment of dyslipidemia with evolocumab in people who have experienced a prior myocardial infarction, ischaemic stroke or TIA, and who are taking a highly effective dose of a statin, reduces the risk of recurring or additional cardiovascular events. Participants in this study have clinically evident cardiovascular disease.
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