Endo sues Indian drug maker over anti-smoking drug patent
Patent-in-suit relates to a synthetic drug used to treat nicotine dependence | Development comes after US Food and Drug Administration sets new guidelines forcing the withdrawal of another big pharma firm’s rival drug.
Endo subsidiary Par Pharmaceuticals (Par) has filed a lawsuit against the Indian generic drug maker Zydus for the alleged infringement of a treatment, varenicline, that helps people to quit smoking.
The case, filed on August 8 at the US District Court for the US District of Delaware, alleges the patent infringement of US patent number 11, 717, 524.
The patent-in-suit relates to a method of producing varenicline tartrate tablets with minimal levels of nitrosamine impurities, as per the US Food and Drug Administration’s (FDA) requirements.
Varenicline tartrate is a synthetic drug useful in treating nicotine dependence, addiction, and withdrawal.
Zydus stands accused of infringing Par’s IP rights by manufacturing and distributing generic versions of the drug.
The suit claims Zydus has used the patented manufacturing methods outlined in the '524 patent to make its new drug.
Par also suggested that Zydus’ “careful adherence to Par’s methods” extend to importing the tablets and selling them in the US.
‘A race to the market’
The plaintiffs argue that the defendant’s actions, including the commercial manufacture and sale of their generic varenicline tartrate tablets, infringes its technology.
Zydus launched their allegedly infringing product after Par informed them of its upcoming approval of the ‘524 patent but before Par could take legal action on the finalised patent.
The company then filed an Abbreviated New Drug Application (ANDA number 216723) seeking approval for the production and commercial distribution of generic varenicline tartrate tablets already offered by Par.
Now that the USPTO has issued the ‘524 patent, Par wants to obtain a ruling that states Zydus has violated the patent by selling its version of the varenicline tablets.
Par is seeking various forms of relief, including injunctive measures, monetary damages, and attorneys' fees.
Pfizer’s attempt to produce similar drug
This development comes after the US Food and Drug Administration (FDA) set more stringent guidelines relating to this particular treatment.
In 2006, Pfizer received FDA authorisation to manufacture and market varenicline tartrate tablets under the brand name Chantix for quitting smoking, generating annual revenues exceeding $1 billion at its peak.
But the pharma firm later withdrew Chantix in July 2021, due to its high levels of N-nitroso-varenicline—a nitrosamine impurity associated with potential cancer risks in humans.
The FDA issued guidelines offering recommendations for evaluating nitrosamine risk in the drug products, as well as setting acceptable daily intake limits.
In July 2021, Pfizer initiated a recall of nine commercial lots of Chantix due to the presence of N-nitroso-varenicline levels surpassing the FDA's acceptable limit, leading to the discontinuation of Pfizer's varenicline tartrate offerings.
In contrast to Pfizer's challenges, Par pursued a new drug application for varenicline tartrate products and successfully developed tablets with nitrosamine levels below the FDA's acceptable intake limit.
In August 2021, the FDA granted approval for Par's drug application.
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