Why Did Lupin and Zydus Share Price Decline Sharply?

Lupin Ltd. and Zydus Lifesciences Ltd., 2 leading Indian pharmaceutical companies, faced a major legal setback in the United States concerning their generic versions of Mirabegron. Mirabegron is the generic formulation of Myrbetriq, a drug developed by Astellas Pharma to treat overactive bladder (OAB) and neurogenic detrusor overactivity (NDO) in paediatric patients.

Astellas Pharma filed a lawsuit against both companies, alleging that their generic offerings infringed on the patent rights protecting Myrbetriq, specifically Patent 780.

As of 1:54 PM, Lupin share price was down by 3.6%, and Zydus Lifesciences share price had plunged over 6.5%. 

Court Ruling: A Victory for the Innovator

Following a bench trial, the US Federal Court ruled in favour of Astellas, upholding the validity of the contested patent. This judgment effectively prevents Lupin and Zydus from marketing or selling their versions of Mirabegron in the US market until the patent expires or is otherwise invalidated.

The ruling is considered a critical win for Astellas, reinforcing its market exclusivity over the drug. For Lupin and Zydus, however, the verdict represents a significant blow, as they may now be compelled to halt sales and potentially withdraw existing inventory from distribution.

Financial Implications for Indian Drugmakers

According to the report, the financial stakes were notable. Zydus Lifesciences was estimated to be generating around $35 million in quarterly revenue from its Mirabegron sales in the United States. Similarly, Lupin’s quarterly revenue from the product was believed to be in the range of $25–30 million.

The loss of these revenues, coupled with potential financial penalties or litigation costs, could impact the near-term financial performance of both companies.

Timeline of Events and Regulatory Context

Lupin had entered the US market with its generic Mirabegron following approval from the US Food and Drug Administration (USFDA). However, this launch occurred before the resolution of Astellas’ patent lawsuit. The recent court ruling supersedes the USFDA approval, highlighting that regulatory clearance does not nullify ongoing patent protections.

Both Lupin and Zydus had already introduced the 25 mg dosage of Mirabegron and were preparing to roll out the 50 mg dosage before the legal proceedings halted further expansion.

About Myrbetriq and Its Market Significance

Myrbetriq is a widely prescribed treatment for overactive bladder, a condition marked by symptoms such as frequent or urgent urination and urinary incontinence. It also has approval for treating neurogenic detrusor overactivity in children.

Developed and marketed by Astellas Pharma Global Development, Myrbetriq holds a strong position in the urology pharmaceutical segment, and its exclusivity in the US is a substantial source of revenue for the innovator.

Conclusion

The court’s decision in favour of Astellas has broader implications for the generic pharmaceutical landscape. It underscores the importance of patent law in shaping market access for generics, regardless of regulatory approval.

While this ruling marks a pause in the Mirabegron competition for now, it also reiterates the complex relationship between innovation protection and generic entry in the pharmaceutical industry.

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