[co-author: Ben Brahm]
On July 28, 2021, the U.S. Food and Drug Administration (FDA) announced a landmark approval of Viatris Inc.’s Semglee® as the first interchangeable biosimilar product. Semglee® (insulin glargine-yfgn), indicated to control high blood sugar in adults with Type 2 diabetes and adults and pediatric patients with Type 1 diabetes, is the first biosimilar that can be substituted at the pharmacy counter for its reference product, Lantus®.
In 2009, as part of the Affordable Care Act, the FDA created the pathway for approval of biosimilars. These biologic therapeutics must be “highly similar” to their reference product and without clinically meaningful differences in their safety, purity, and potency. However, it was not until 2019 that the FDA released its industry guidance for the testing and data that would be sufficient to achieve interchangeability classification.1 In addition to the previous requirements, the FDA mandated showing that safety and efficacy risks from switching between the two drugs is “not greater” than the risk of using the reference drug alone. Equipped with greater understanding of the regulatory expectations, Viatris worked with the FDA to make Semglee® the first to achieve the vaunted designation as an interchangeable biologic. With this designation comes 12 months of market exclusivity as the only interchangeable biologic with Lantus®.
Despite receiving the prestigious designation, the road to marketability is not without significant hurdles in other areas. While the FDA has approved 30 biosimilars since 2015, many of those therapeutics are either not available or not available in their most desired form. The history of Semglee® is representative of the struggle many biosimilar companies face.
When Viatris first filed its new drug application (NDA) for Semglee®in 2017, it and Biocon, its manufacturing partner, were immediately met with a patent infringement lawsuit from Lantus® manufacturer Sanofi. This lawsuit automatically triggered a 30-month stay on approval of Viatris’ application. Sanofi alleged infringement of 18 patents, including patents related to the drug product as well as the injector pen device for administering the therapeutic. Because diabetes treatments require daily and often public injections, the injection device is an important part of being able to offer patients a truly competitive product.
Viatris strategically responded to each of the alleged infringements using the full array of options available in intellectual property disputes. Through inter partes reviews (IPR), the validity of Sanofi’s Lantus® patent portfolio was brought back under the scrutiny of the U.S. Patent and Trademark Office (USPTO) with new prior art references submitted to the Patent and Trademark Appeals Board (PTAB). First, the PTAB found that the references Viatris provided demonstrated that Sanofi’s reformulation patents (U.S. Patent Nos. 7,476,652 and 7,713,930) were unpatentable. This finding was subsequently upheld by the Federal Circuit in 2019.2 Additional IPRs directed to Sanofi’s device patents (U.S. Patent Nos. 8,603,044; 8,679,069; 8,992,486; 9,526,844; 9,604,008; and RE47,614) were also successful in demonstrating that the patents’ claims and amendments were unpatentable. Finally, in March of 2020, the U.S. District Court for the District of New Jersey held that the sole patent tried of the 18 originally asserted, U.S. Patent No. 9,526,844, was both invalid for lack of a sufficient written description and not infringed.3 Final judgment was subsequently entered in the case, leaving no outstanding claims of infringement, pending appeals.
With the legal and regulatory hurdles successfully navigated over the last four years, Viatris now has the opportunity to bring its interchangeable product to the American public. This will bring much desired competition to the recombinant insulin market.
Wilson Sonsini represented Viatris in the insulin glargine Inter Partes review and litigation matters.
 Food and Drug Administration, FDA-2017-D-0154, Considerations in Demonstrating Interchangeability with a Reference Product Guidance for Industry (2019).
 Sanofi-Aventis Deutschland GMBH v. Mylan Pharms. Inc., 791 F. App'x 916 (Fed. Cir. 2019), cert. denied, 141 S. Ct. 266, 208 L. Ed. 2d 33 (2020).
 Sanofi-Aventis U.S. LLC v. Mylan GmbH, No. CV 17-9105 (SRC), 2019 WL 2067373 (D.N.J. May 9, 2019).