Shares of pharmaceutical company Dr. Reddy's Laboratories were tumbling on Friday after it said that the drugmaker and its subsidiary could be involved in an antitrust case in the US.

What Happened: The company and its unit were named as defendants in a complaint in the U.S. District Court for the District of New Jersey.

The complaint, filed by Walgreen, Kroger Specialty Pharmacy and CVS Pharmacy, asserts claims under federal antitrust law, alleging that Dr. Reddy’s, in connection with Celgene Corporation, Bristol-Myers Squibb Co, Natco Pharma and Teva Pharmaceuticals USA, improperly restrained competition and maintained a shared monopoly in the sale of brand and generic Revlimid through their respective settlements of patent litigation.

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Dr. Reddy’s has said that the allegations against it lack merit and asserted that it will vigorously defend the litigation.

Price Action: Dr. Reddy’s share price ended Friday’s session down 3.65% at ₹6,190, its lowest in just under a month.

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