Medicis Pharmaceutical Corp said generic drugmaker Actavis Mid Atlantic filed a marketing application for a generic version of one of Medicis' skin drugs.
The drug Zyclara is used to treat patients with actinic keratosis, a small, red, raised area on the skin that has been exposed to the sun for a long time.
Zyclara is currently protected by two patents, one of which is valid until 2029. The cream's seven-year marketing exclusivity will expire in March 2013.
Medicis said it will defend its intellectual property rights relating to the product. Zyclara is one of the company's key non-acne dermatology products.
The Scottsdale, Arizona-based Medicis acquired Zyclara through its purchase of the bankrupt drugmaker Graceway Pharmaceutical LLC for $455 million in November.
Medicis, which focuses primarily on the treatment of dermatological conditions, has a market value of $1.93 billion as of Tuesday's close.
The company's shares closed at $32.23 on Tuesday on the New York Stock Exchange.
(Reporting by Adithya Venkatesan in Bangalore; Editing by Sreejiraj Eluvangal)