By Alexandra Foster


Paris-based drug maker Sanofi AG is yet again seeking to protect its closely guarded, best-selling diabetes drug, Lantus, by filing a lawsuit against Merck & Co. alleging as many as ten patent violations and seeking to prevent the United States drug maker from launching a rival product.[1]

After Merck filed for a new drug application with the U.S. Food and Drug Administration, the French multinational pharmaceutical company sued in the U.S. District Court of Delaware, claiming Merck’s international division “violated as many as ten patents” in an attempt to introduce a biosimilar diabetes drug to the market.[2] The diabetes division represents twenty percent of Sanofi’s profits, with Lantus and its insulin delivery device soloSTAR grossing seven billion dollars in 2014 sales.[3] Merck’s spokeswoman claims the new biosimilar insulin glargine product does not infringe on the Sanofi patents.[4]

The United States adopted the TRIPS agreement in 1995, agreeing to protect international and domestic patent owners for twenty years.[5] Under Article 33 of TRIPS, Sanofi has enjoyed an uninterrupted twenty-year run of patent protection for its diabetes drug Lantus.[6]

This is not the first time Sanofi has turned to the judicial system to protect Lantus. In 2012 Sanofi sued pharmaceutical company Eli Lilly under similar conditions, but settled out of court with a result that Eli Lilly postpone marketing its biosimilar for types 1 and 2 diabetes until 2016.[7] Under the terms of the settlement, this is the year that Eli Lilly may introduce its insulin glargine product to the market. Coincidentally (or perhaps not), Sanofi’s twenty-year patent protection for Lantus terminates this year as well. The pharmaceutical market is bound to see biosimilar insuline glargine products from other big-name drug companies rapidly enter the market.[8]

If Merck prevails over the patent infringement claims, the introduction of another biosimilar product will create further competition between the pharmaceutical companies. This will be good for consumers, as wide availability of generics and competition between three large companies as well as others planning to enter the market will inevitably lead to lower prices at the pharmacy. For Sanofi the results may be slightly less positive; the company has not been reported to have another “blockbuster” drug ready to replace Lantus.[9]

Of course, one can reasonably assert that Sanofi’s fiscal losses may not be as drastic, nor as soon, as expected. The company has enjoyed a hold on the market for years, and the introduction of biosimilar insuline glargine products may still take years for doctors and drugstores to begin prescribing and carrying.

In addition, Sanofi is the fifth largest prescription drug manufacturer in the world, and made over 37 billion dollars in 2015. It would be juvenile to assume this pharmaceutical giant would not have planned for the day when its diabetes drug lost its patent protection. It has known since 1996 that 2016 would be the year its twenty-year Lantus patents expire, and since its settlement with Eli Lilly in 2012 that 2016 would be the year for its settlement terms to vest.

With a new, long-acting basil insulin Toujeo in the works, perhaps it is time for Sanofi to stop worrying about the future of Lantus.   Sanofi has seven major therapeutic divisions within the company;[10] by concentrating efforts away from its diabetes division, Sanofi could instead focus its efforts in developing a stand-out product in another market.

[1] Noemie Bisserbe & Inti Landauro, Sanofi Files Suit Against Merck, Claiming Patent Infringements, Wall Street Journal (Sept. 19, 2016, 11:19 AM),

[2] Id.

[3] Tracy Staton, Sanofi Patent Deal Lets Lilly Roll Out a Lantus Biosim in U.S. Next December, FiercePharma (Sept. 28, 2015, 11:37 AM),

[4] Bisserbe & Landauro, supra note 2.

[5] Gene Quinn, How Long Does a Patent Last? IP Watchdog (Jul. 26, 2014),


[7] Bisserbe & Landauro, supra note 2.

[8] Paul Whitfield, Sanofi Fighting a Losing Battle, Sues Merck for Alleged Patent Infringement, The Street (Sept. 19, 2016),

[9] Id.

[10] Sanofi-Aventis to Sign Deal to Build Flu Vaccine Plant in China, Forbes (Nov. 23, 2007) (cardiovascular, central nervous system, internal medicine, diabetes, oncology, thrombosis, vaccines).

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