(Adds analyst comment; updates shares)
April 17 (Reuters) - Teva Pharmaceutical Industries Ltd signed a deal that allows the Israeli drugmaker to launch a generic version of Pfizer Inc's blockbuster painkiller Celebrex in December.
A U.S. court in March invalidated a patent extending Pfizer's marketing exclusivity for Celebrex to Dec. 2, 2015. Celebrex's basic chemical patent is set to expire this May.
Pfizer said on Thursday it would continue to defend the patent extending its marketing exclusivity.
"(The deal) helps them to get through 2014 with a lot less competition," Morningstar analyst Damien Conover said.
"As soon as other generics get in, (Pfizer's) sales will erode even quicker."
The U.S. Food and Drug Administration usually grants 180 days of marketing exclusivity to drugmakers who are first to file for generic approvals.
Teva, the world's largest generic drugmaker, said it believed it was the first to file for an approval of a generic version of at least three of the four dose strengths of Celebrex.
"I think Teva was concerned about the second patent that potentially could hold, so to reduce the risk, they said they would launch later," Conover said.
The deal settles Pfizer's patent infringement lawsuit against Teva.
The U.S. drugmaker has also sued other generic drugmakers, including Mylan Inc and Actavis Inc, which are seeking U.S. regulatory approval to sell their own versions of Celebrex.
Deals between patent holders and generic drug makers have come under increasing regulatory scrutiny because of their potential to delay the launch of cheaper medicines.
The U.S. Federal Trade Commission is seeking a settlement of $1 billion or more from drugmakers, including AbbVie Inc , Actavis Plc and Teva, for settling patent-related lawsuits that allegedly end up making drugs more expensive.
Celebrex, which is used to treat arthritis pain and inflammation, generated about $2.92 billion in sales in 2013, according to Pfizer's annual regulatory filing.
"Under certain conditions, the license will be royalty-bearing, through the remaining term of the patent (Dec. 2, 2015)," a Pfizer spokesman told Reuters in an email.
The company declined to reveal other terms of the settlement.
Teva's U.S.-listed shares were up 1 percent at $50.41 in afternoon trading on the New York Stock Exchange, while Pfizer's shares were little changed at $30.24.
(Additonal reporting by Esha Dey in Bangalore; Editing by Kirti Pandey, Prateek Chatterjee and Sriraj Kalluvila)