Bayer shares tumbled to a 12-month low yesterday after a US judge ended the pharmaceutical giant's patent on Yasmin, the company’s top-selling birth control pill. The ruling means rival Barr Pharmaceuticals may introduce a lower-priced generic version of Yasmin in the next few months, Bloomberg reports.
Sales of Yasmin generated $490 million for Bayer in the US last year, and the drug and related contraceptives accounted for the biggest chunk of Bayer’s pharmaceutical revenue. American sales of Yasmin could fall by up to 50% in the first year after the launch of a generic version, said one analyst. Bayer, Germany’s largest pharmaceutical firm, may appeal the judge’s ruling.