Monoclonal antibody boosts cholesterol reduction

By Sally Robertson, B.Sc.Nov 9 2012

Adding a monoclonal antibody that blocks the breakdown of lipid receptors to atorvastatin therapy further reduces low-density lipoprotein (LDL) cholesterol levels in patients with primary hypercholesterolemia, show study findings.

The combination of the antibody, dubbed SAR236553, and 80 mg atorvastatin resulted in twice as many patients reaching a target LDL cholesterol level of less than 100 mg/dL as did with atorvastatin and placebo, and more than five times as many obtaining levels under 70 mg/dL.

Futhermore, no specific safety concerns were identified with the antibody therapy, report Evan Stein (Metabolic and Atherosclerosis Research Center, Cincinnati, Ohio, USA) and colleagues in TheNew England Journal of Medicine.

"Statins are highly efficacious in lowering LDL cholesterol. However, many patients, especially those with very high initial LDL cholesterol levels and those who have unacceptable side effects with high-dose statins, do not reach recommended target levels of LDL cholesterol," explains the team. "There remains a considerable unmet need for additional, more effective therapeutic options that have acceptable side-effect profiles."

The antibody investigated in the current trial prevents an enzyme called serum protein convertase subtilisin/kexin 9 (PCSK9) from binding to and degrading LDL cholesterol receptors and thereby disrupting the removal of LDL cholesterol from the circulation.

For the study, the team recruited 92 patients with LDL cholesterol levels that remained higher than 100 mg/dL after 7 weeks of treatment with 10 mg atorvastatin.

Among those who were randomly allocated to receive 80 mg of atorvastatin plus SAR236553, the mean LDL cholesterol level reduced by 73.2% from baseline after 8 weeks of treatment. This compared with a mean reduction in LDL cholesterol of 17.3% among those on 80 mg of atorvastatin plus placebo, giving a mean absolute difference of 55.9%.

Furthermore, the LDL cholesterol reduction from baseline among patients who took 10 mg of atorvastatin plus SAR236553 was also greater than with 80 mg atorvastatin and placebo, at a mean of 66.2%.

All of the patients in the two groups assigned SAR236553 achieved the target level of less than 100 mg/dL, compared with only 52% of those in the atorvastatin plus placebo group.

Similarly, the target level of less than 70 mg/dL was achieved in 90% of those who received atorvastatin 80 mg plus SAR236553 and in 97% of those who received atorvastatin 10 mg plus SAR236553, compared with 17% of those who received atorvastatin plus placebo.

Overall, the proportion of patients who reported at least one adverse event occurring during study treatment was similar in the two groups assigned to 80 mg of atorvastatin (approximately 60%) and was lower in the group assigned to 10 mg of atorvastatin plus SAR236553.

The team says their findings warrant further confirmation in large, longer-term studies.

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