Over four years ago, in October 2014, Amgen initiated a patent infringement suit against Sanofi and Regeneron regarding biologics for treatment of high cholesterol. The case reached an important milestone recently as a jury entered a verdict largely upholding the validity of Amgen’s asserted patents, to the disappointment of Sanofi and Regeneron. A similar decision had previously been entered in March 2016, but the Federal Circuit then found error and remanded for a new trial. Based on statements by Sanofi and Regeneron, the most recent decision may be appealed as well.
Amgen’s drug Repatha® (“Repatha”) uses the monoclonal antibody evolocumab to inhibit PCSK9 from destroying low-density lipoprotein (LDL) receptors, which are responsible for extracting LDL cholesterol, or “bad cholesterol,” from the bloodstream. Repatha and other PCSK9 inhibitors thereby lower a patient’s LDL cholesterol levels and thus aid in the prevention of heart attacks, strokes, and cardiovascular disease. Amgen began developing Repatha in early 2005 and received FDA approval in August 2015. Starting in September 2007, Sanofi and Regeneron jointly developed their own drug, Praluent® (“Praluent”), which includes the PCSK9 inhibitor alirocumab as an active ingredient. The FDA approved Praluent in July 2015. Sales data demonstrates these companies’ motivation behind the protracted legal battle over Amgen’s patents. For net sales in the United States in 2018, Amgen reported $358 million for Repatha (up from $225 million in 2017), and Sanofi and Regeneron reported $181.3 million for Praluent (up from $131.4 million in 2017).
The patents at issue are Amgen’s U.S. Pat. Nos. 8,829,165 (“the ’165 patent”) and 8,859,741 (“the ’741 patent”). The relevant claims cover a genus of antibodies that bind to specific amino acid residues on PCSK9 and block PCSK9 from binding to LDL receptors. The patents are not limited to claiming Amgen’s Repatha, or any other antibody, by amino acid sequence, and Amgen asserted that the patents are infringed by Sanofi and Regeneron’s Praluent. Sanofi and Regeneron stipulated to infringement but challenged the validity of the patents. The parties proceeded to a first trial in March 2016, and the jury returned a verdict finding the asserted claims valid. Specifically, the jury found that Sanofi and Regeneron failed to prove by clear and convincing evidence that the claims of the ’165 and ’741 patents are invalid for lack of enablement or lack of written description. In January 2017, following post-trial motion practice, the district court entered a final judgment in favor of Amgen and granted a permanent injunction enjoining sales of Praluent.
On appeal, the Federal Circuit determined that the district court had erred by excluding Sanofi and Regeneron’s post-priority-date evidence regarding written description and enablement and by improperly instructing the jury on written description. Amgen Inc. v. Sanofi, 872 F.3d 1367, 1380-81 (Fed. Cir. 2017). The Federal Circuit therefore vacated the judgment as to written description and enablement and remanded for a new trial on these two issues, further vacating the permanent injunction. Id. In January 2019, the Supreme Court denied Amgen’s petition for a writ of certiorari.
A second trial was held, and the jury entered a verdict at the conclusion of the trial on February 25, 2019. This time, while the jury found that two asserted claims of the ’165 patent are invalid for lack of adequate written description, the jury again found that two other asserted claims of the ’165 patent and one asserted claim of the ’741 patent are not invalid for lack of enablement or written description.
Thereafter, Amgen was quick to claim victory, with its chairman and CEO stating that Amgen is “thankful that the jury weighed the evidence carefully and recognized the validity of Amgen’s patents.” Amgen’s press release also referenced decisions in foreign patent offices regarding the validity of its PCSK9 antibody patents and announced Amgen’s plan to enforce these patents against Sanofi and Regeneron in the national courts of Europe and Japan. On the other hand, Sanofi and Regeneron issued a press release expressing disappointment and announcing that they “strongly disagree with certain aspects of [the] jury verdict” upholding three of the five asserted claims. In the press release, Sanofi and Regeneron stated their intent to utilize post-trial motion practice to seek to overturn the jury verdict and request a new trial, as well as their intent to appeal to the Federal Circuit again “if necessary.” Although this litigation may be far from over, the recent verdict is a key development.
 Amgen Inc. v. Sanofi, No. 1:14-cv-01317 (D. Del.)
 https://www.amgen.com/media/news-releases/2019/01/amgen-reports-fourth-quarter-and-full-year-2018-financial-results/; see also Form 10-K filed with the S.E.C.
 https://newsroom.regeneron.com/news-releases/news-release-details/regeneron-reports-fourth-quarter-and-full-year-2018-financial; see also Form 10-K filed with the S.E.C.
 https://newsroom.regeneron.com/news-releases/news-release-details/regeneron-and-sanofi-strongly-disagree-verdict-upholding-three; http://www.news.sanofi.us/2019-02-25-Sanofi-and-Regeneron-strongly-disagree-with-verdict-upholding-three-of-five-Amgen-U-S-patent-claims-relating-to-PCSK9-antibodies