Here’s why shares of Lupin and Zydus Life are under pressure on Tuesday

Shares of Lupin Ltd. and Zydus Lifesciences Ltd. declined up to 3% on Tuesday, April 28, after developments around the drug Mirabegron raised concerns about rising competition.MSN Laboratories has reached a settlement with Astellas Pharma on April 24 for the generic version of Mirabegron, a drug used to treat overactive bladder.

As part of the agreement, MSN will pay $75 million to Astellas, signalling a potential near-term launch of its generic in the US market.
Zydus and Lupin had earlier launched Mirabegron at risk in 2024 and later settled with Astellas in February 2026.Under their agreements, Zydus is paying $120 million and Lupin $90 million in licensing fees to market the drug until September 2027.

Analysts believe the MSN settlement could open the door for additional generic entrants. An early launch by MSN may impact earnings estimates for both Lupin and Zydus for FY27.

Mirabegron contributes meaningfully to both companies’ earnings. For Lupin, it accounts for around 5-6% of FY27 revenue and 9-10% of EBITDA estimates, while for Zydus, it contributes about 4-5% of revenue and 7-8% of EBITDA.

Separately, Lupin may also face competition in its Tolvaptan portfolio by the end of FY27, following approval for a generic version by Alkem.