By Thomas Dunlap

[Dec. 08, 2020]  Nearly two years before patent expiration, Merck, Sharp & Dohme Corp’s (Merck) diabetes drug, Janumet, is at the center of another patent infringement case. In response to an Abbreviated New Drug Application (ANDA) filed with the Food and Drug Administration (FDA) by Ajanta Pharma Ltd., Merck is suing for alleged patent infringement.[1] The patent in question is U.S. Patent No. 7,326,708 (the ‘708 patent), issued in July of 2008.[2] The ‘708 patent contains the claims for the brand name drug Janumet (metformin hydrochloride and sitagliptin Phosphate), listed in the FDA’s Orange Book, is a well-known Type-2 Diabetes treatment drug.[3]

What is ANDA litigation?  

ANDA litigation generally is a result Drug Price Competition and Patent Term Restoration Act (commonly known as the Hatch-Waxman Act) that was enacted as an effort to control the pharmaceutical marketplace and pricing. One of the amendments to the original act included a process for FDA approval on an abbreviated timeline of generic versions of patented “name brand” pharmaceuticals through the filing of an Abbreviated New Drug Application (ANDA) together with the corresponding right of a patent holder to, in turn, file patent litigation against an ANDA applicant as is the case with Merck and Ajanta. These applications are “abbreviated” instead of a regular NDA (or New Drug Application) because they do not require preclinical and clinical data. Instead, the ANDA applicants must simply prove that their proposed generic product is bioequivalent of an existing pharmaceutical, often called the innovator drug.  

According to the Merck patent infringement complaint filed on November 4, 2020, Ajanta, in its ANDA application, asserts that the ’708 patent is invalid, unenforceable, and/or will not be infringed by the manufacture, use, offer for sale, sale, and/or importation of Ajanta’s ANDA Product. Therefore Ajanta should have the right to manufacture and sell its generic form of the product before the expiration of Merck’s patent. Merck’s complaint requests an order prohibiting the FDA from approving Ajanta’s ANDA until the ‘708 patent’s expiration date in 2022.[4] In addition, the complaint seeks an injunction against Ajanta “from the commercial manufacture, use, sale, offer for sale, or importation into the United States of Ajanta’s ANDA Product” and a declaration that any future use (before patent expiration) will be rendered an infringement, as well.[5] 

The defendant, Ajanta Pharma Ltd, is a pharmaceutical company headquartered in Mumbai, India.[6] Joining Ajanta Pharma as a defendant is the company’s U.S. subsidiary, Ajanta Pharma USA Inc.[7] The ANDA filed by Ajanta Pharma is alleged to contain the generic version of Janumet and contains the same ingredients.[8]

Though Ajanta has not brought the Janumet bioequivalent/generic to market and is pending FDA approval, Merck’s complaint alleges that “upon approval of Ajanta’s ANDA, Ajanta will manufacture, market, sell, and distribute Ajanta’s ANDA product throughout the United States.” [9] Ajanta Pharma has not filed a response or issued a statement yet.

Ajanta Pharma Ltd. is not the first company to face legal challenges from Merck over the ‘708 patent. Merck has sued other companies, including Dr. Reddy’s Labs, Aurobindo Pharma, and Mylan NV (now a part of Viatris[10]) for alleged infringement of the Janumet patent and similar diabetes treatment, Januvia (sitagliptin phosphate) in the wake of their respective ANDA applications.[11] None of these cases have been decided yet, with the Mylan case set to be heard in late 2021.[12] Previously, Merck also sued Accord Healthcare for alleged infringement over the drug Januvia.[13] This case resulted in an undisclosed settlement between the two parties.[14]

Together, Januvia and Janumet account for a large portion of Merck’s financial profile with over $5.5 billion in product life revenues.[15] In the third quarter of 2020 alone, Januvia and Janumet collectively raked in $1.3 billion for the pharmaceutical giant.[16] The diabetes drug sales came second for highest-grossing drug sales, only to Merck’s cancer drug, Keytruda.[17] Because of these high profits for Januvia and Janumet, it is not surprising that several companies are challenging the ‘708 patent, not that Merck is aggressively defending the ‘708 patent, which will expire in July of 2022. 

After expiration, other pharmaceutical companies will be able to use the patent to manufacture and sell generic versions of the drug through the same ANDA process – but without the counter-balancing litigation right by Merck, which ends once the patent is expired. 


[1] Complaint at 1-2, Merck Sharp & Dohme Corp. v. Ajanta Pharma Ltd., No. 1:99-mc-09999 (D. Del. November 4, 2020), ECF 1236.

[2] Id. 

[3] Kevin Stawicki, Merck Plows Ahead With Another Suit Over Diabetes Drug, Law 360 (November 5, 2020), https://www.law360.com/articles/1326111/merck-plows-ahead-with-another-suit-over-diabetes-drug

[4] Complaint, supra note 1 at 10. 

[5] Id. 

[6] Stawicki, supra note 3. 

[7] Id. 

[8] Id. 

[9] Complaint, supra note 1 at 1. 

[10] Gough, After Nearly 60 Years, Mylan Makes Way for Viatris, Pittsburg Bus. Times (Nov. 16, 2020), https://www.bizjournals.com/pittsburgh/news/2020/11/16/after-nearly-60-years-mylan-makes-way-for-viatris.html.

[11] Stawicki, supra note 3. 

[12] Id. 

[13] Id. 

[14] Id. 

[15] Merck Announces Third-Quarter 2020 Financial Results, Merck (October 27, 2020), https://s21.q4cdn.com/488056881/files/doc_financials/2020/q3/Merck-3Q20-Earnings-News-Release.pdf

[16] Id. 

[17] Id. 

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Posted in: Intellectual Property - Patents