The PCSK9 protein inhibitor evolocumab may soon be approved by the FDA to treat high cholesterol levels in those not responding to statin therapy.
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Evolocumab acts on a protein called PCSK9 (proprotein convertase subtilisin/kexin type 9) in the body. PCSK9 binds to the LDL-cholesterol receptor and directs it into the liver cells to be destroyed. Thus, there are less number of LDL-cholesterol receptors to take up LDL cholesterol from the blood, and the blood level of LDL cholesterol rises. Evolocumab blocks the protein PCSK9 and thereby prevents the breakdown of LDL-cholesterol receptors.
Evolocumab causes reductions in LDL-cholesterol much more as compared to statins, the current drugs of choice for treating high LDL-cholesterol levels. The drug is likely to be approved for homozygous familial hypercholesterolemia. This is a genetic condition where the patient has extremely high LDL levels. It is possible that it may be approved for high LDL – cholesterol levels due to other causes as well which cannot be controlled with statins or if patients develop side effects to statins. It will be available as an injection of 140mg to be administered once in two weeks, or 420 mg once a month.
However, further studies will be required regarding the long-term safety of this drug. Because of the large dose administered in a single injection, there is a possibility that the blood LDL-cholesterol levels may fall too low below normal. Also, long-term studies will also be required to address if the drug can prevent heart attack and extend life.
Amgen, the company that manufactures evolocumab, plans to market it under the name of Repatha. Another PCSK9 blocker, alirocumab marketed by Regeneron and Sanofi, is also seeking approval for marketing.