Genzyme and Isis Pharmaceuticals announce phase 3 study data of mipomersen

Genzyme Corp. (NASDAQ: GENZ) and Isis Pharmaceuticals Inc. (NASDAQ: ISIS) announced that data from the phase 3 study of mipomersen in patients with homozygous familial hypercholesterolemia (hoFH) were presented today at the American Heart Association’s Scientific Sessions. The study met its primary endpoint in an intent-to-treat analysis, with a 25 percent reduction in LDL-cholesterol after 26 weeks of treatment, vs. 3 percent for placebo (p<0.001) which constitutes an average reduction greater than 100 mg/dL. The trial also met each of its secondary endpoints.

This phase 3 study in hoFH patients, one of the largest trials to date in this rare population, was designed to test the efficacy and safety of adding mipomersen to substantial lipid-lowering therapy. Patients’ average LDL-C at baseline was greater than 400 mg/dL. All but one of the patients were being treated with lipid-lowering therapy (50/51, 98 percent), of whom 11 (22 percent) were taking a statin alone and 39 (78 percent) were taking a statin in combination with at least one other lipid-lowering agent, most commonly ezetimibe (37/50, 74 percent). The LDL-C reductions observed in the study were in addition to those achieved with the patients’ existing therapeutic regimen.

“These results are good news for patients with hoFH,” said Professor Frederick J. Raal, Ph.D., Director of the Carbohydrate and Lipid Metabolism Research Unit at the University of the Witwatersrand in South Africa, and the study’s primary investigator. “These patients are at very high risk of cardiovascular events despite being on currently available treatments, and their life expectancies are limited due to the severity of the disease. Mipomersen has the potential to change the standard of care for hoFH patients.”

The trial met all of its secondary and tertiary endpoints, suggesting that mipomersen may offer potential benefits to patients beyond LDL-C reduction. Patients treated with mipomersen experienced a 27 percent reduction in apolipoprotein B vs. 3 percent for placebo; a 21 percent reduction in total cholesterol vs. 2 percent for placebo; and a 25 percent reduction in non-HDL cholesterol vs. 3 percent for placebo (all p<0.001).