UPDATE 2-Sepracor claims patent rights on Wyeth's Pristiq

* Patent board to hear dispute in January 2010

* Wyeth launched Pristiq antidepressant last year

(Adds Wyeth comment)

NEW YORK, April 17 (Reuters) - Specialty drugmaker Sepracor Inc SEPR.O said on Friday it is claiming patent rights on Wyeth's WYE.N Pristiq antidepressant.

The Board of Patent Appeals and Interferences has set Jan 6, 2010, for oral arguments on the matter, it said.

The Marlborough, Massachusetts-based company said that if it prevails, it could obtain patent rights that would be infringed by Wyeth’s sale of Pristiq.

Sepracor said the first patent application filing date it asserts is about 22 months earlier than the first application filing date asserted by Wyeth.

Wyeth said in a statement it would “prove during the upcoming proceedings before the patent office that we invented desvenlafaxine and that Sepracor’s position is without merit.” Desvenlafaxine is the chemical name for Pristiq.

Pristiq, a derivative of Wyeth’s $3.9 billion blockbuster antidepressant Effexor, was first sold in the United States last year. Wyeth recorded $66.5 million in Pristiq sales in 2008. The drug faced initial resistance from insurers over reimbursement.

Before agreeing in January to be acquired by Pfizer Inc PFE.N for $68 billion, Wyeth had been counting on Pristiq to help replace Effexor sales when Effexor loses patent protection next year. (Reporting by Lewis Krauskopf; editing by John Wallace, Dave Zimmerman)