" Genetic data have shown that patients with natural loss-of-function mutations in PCSK9 have significantly lower LDL-C and a lower risk of coronary heart disease," said Dr. Elias Zerhouni, President, Global Research & Development, Sanofi. "Based on this finding and the results of our Phase 2 trials, Sanofi and Regeneron plan to initiate the SAR236553/REGN727 Phase 3 program in the second quarter."Data from a separate trial, "Study DFI11566," were presented yesterday during an oral session of the ACC meeting. The study enrolled patients with primary hypercholesterolemia with elevated LDL-C (greater than or equal to 100 mg/dL) who were on a stable low dose of atorvastatin (10 mg). The primary objective of the study was to compare the effect on LDL-C lowering of switching to a high dose of atorvastatin alone (80 mg) versus a high dose of atorvastatin combined with SAR236553/REGN727. Patients who received SAR236553/REGN727 plus atorvastatin 80 mg achieved a mean reduction of 73% in LDL-C, compared to a mean reduction of 17% for patients who switched to atorvastatin 80 mg alone (p<0.001) after eight weeks. The study also included a third arm in which SAR236553/REGN727 was added to the stable low dose of atorvastatin. Patients in this arm achieved a 66% reduction in mean LDL-C. Patients in the study were followed for a total of 16 weeks for safety. In this trial, the most common AE with SAR236553/REGN727 was infection. There was one serious AE in the SAR236553/REGN727 plus atorvastatin 80 mg group (dehydration) that was deemed not to be treatment-related. A long-term safety and tolerability study of SAR236553/REGN727 (NCT01507831) is ongoing in patients with hypercholesterolemia who are not adequately controlled with their current lipid-modifying therapy.(6) Sanofi and Regeneron are intending to initiate Phase 3 clinical studies for SAR236553/REGN727 in Q2 2012. Sanofi and Regeneron are co-developing SAR236553/REGN727 as part of their research and development collaboration agreements. About PCSK9 PCSK9 is known to be a determinant of circulating LDL levels, as it binds to LDL receptors resulting in their degradation so that fewer are available on liver cells to remove excess LDL-cholesterol from the blood. Moreover, traditional LDL-lowering therapies such as statins actually stimulate the production of PCSK9, which limits their own ability to lower LDL-cholesterol. Blocking the PCSK9 pathway is therefore a potentially novel mechanism for lowering LDL-cholesterol.