Amgen recently announced its decision to file an intellectual property lawsuit against Sanofi/Regeneron regarding their PCSK9 inhibitor alirocumab, which is in phase 3 and nearing regulatory submission. For background, PCSK9 inhibitors are an exciting new injectable drug class for lowering LDL cholesterol; phase 3 results on alirocumab as well as Amgen’s evolocumab (which was recently submitted in the US/EU) have shown striking LDL reductions of 50% or more, even in challenging statin-intolerant patients (Pfizer’s bococizumab is next in line, currently in phase 3). Analysts have estimated that the PCSK9 inhibitor drug class could become a blockbuster drug class in fairly short order, and as a result the race to the market has been fierce: Amgen was first to regulatory submission, but Sanofi announced during its 2Q14 update that it and Regeneron had purchased an FDA priority review voucher for $67.5 million that would cut the agency review timeline for alirocumab by four months. The exact implications and next steps of the Amgen lawsuit are currently unclear, but as we learned in the case of Sanofi’s ongoing lawsuit against Lilly/BI regarding the companies’ biosimilar insulin glargine formulation, lawsuits of this nature can potentially result in timeline delays of months or more, even if the case is ultimately ruled in the defendants’ favor. We expect to learn more about the lawsuit early next week, when both Sanofi and Amgen report their 3Q14 earnings.