* Humira patent involved in lawsuit
* Texas jury had awarded $1.67 billion in lawsuit
* Abbott, J&J shares both down slightly (Updates share prices; adds Centocor may appeal)
WASHINGTON, Feb 23 A U.S. appeals court reversed a ruling that Abbott Laboratories' (ABT.N) Humira arthritis drug infringed a patent owned by a Johnson & Johnson (JNJ.N) subsidiary and threw out a $1.67 billion damage award.
The ruling on Wednesday by the U.S. Court of Appeals for the Federal Circuit reversed a 2009 decision by a Texas court.
In that court, a jury awarded $1.67 billion to Centocor Ortho Biotech, the Johnson & Johnson subsidiary.
The appeals court ruled that the patent claims asserted by Centocor were invalid and thus could not be infringed.
The case involves Humira, Abbott's drug that blocks tumor necrosis factor and competes with Johnson & Johnson's older blockbuster medication, Remicade.
Abbott shares closed down 1.1 percent at $46.47 in midafternoon trading, while J&J was down 0.4 percent at $60.39.
Centocor said it was disappointed by the decision. It said the damage award had grown to $1.8 billion because of interest.
"We are considering whether to ask for reconsideration by the panel or by the court of appeals as a whole," said Rob Bazemore, president of Centocor Ortho Biotech Inc.
Abbott said it was pleased.
"The evidence clearly showed that Abbott was first to invent a fully human anti-TNF antibody, HUMIRA," said spokeswoman Adelle Infante.
The case is Centocor Ortho Biotech Inc et al v. Abbott Laboratories et al, Federal U.S. Circuit Court of Appeals, No. 2010-1144. (Editing by Dave Zimmerman; editing by Andre Grenon)