Bristol-Myers Squibb Co. (BMY) disclosed that it has reached agreements to settle certain litigation stemming from its tumultuous efforts three years ago to resolve a patent battle over its top-selling drug Plavix.

In a regulatory filing Thursday, New York-based Bristol said it reached an agreement in principle in May to pay $125 million to settle lawsuits alleging that Bristol and its former chief executive violated U.S. securities laws by failing to disclose material information about its 2006 efforts to settle the Plavix patent litigation.

In 2006, Bristol had reached a tentative agreement with Apotex Inc. of Canada to block Apotex from selling a generic version of Plavix in the U.S. years before the patent expired. But that patent settlement fell apart amid revelations that a Bristol executive made an oral side agreement, and Apotex briefly sold generic Plavix in the U.S. before a judge ordered it to stop. Bristol eventually prevailed in the patent case, but Plavix sales suffered for several quarters, and the debacle led to the ouster of CEO Peter Dolan.

Bristol pleaded guilty to federal criminal charges of lying to the U.S. government about the proposed patent settlement and agreed to pay a $1 million fine in 2007. The former Bristol executive who made the side agreement with Apotex, Andrew Bodnar, also pleaded guilty to lying about the deal and was recently given the unusual sentence of two years of probation during which he must write a book about his experience in the case, and pay a $5,000 fine.

The lawsuits alleging that Bristol and Dolan violated securities laws were filed in federal court in New York in 2007.

Bristol said Thursday that "the parties reached a settlement in principle to resolve this litigation for payment of $125 million, pending final approval by the court." The company had established a reserve of $100 million for this matter in the first quarter.

Separately, Bristol said it reached a settlement in principle last month to resolve so-called shareholder-derivative lawsuits filed in New York state court "for an amount that is not material to the company, pending final approval by the court." The suits were filed against current and former officers of the company, alleging they breached their fiduciary duties by failing to disclose material information related to the Plavix settlement talks.

Also, Bristol said Apotex has challenged the validity of the Plavix patent in Canada. Bristol said its Plavix marketing partner, Sanofi-Aventis SA (SNY), which discovered the drug, last month sued Apotex for patent infringement.

A Bristol spokeswoman couldn't immediately be reached.

Bristol shares rose 3% to $20.89 after reporting improved second-quarter results and announcing the acquisition of biotechnology company Medarex Inc. (MEDX).

-By Peter Loftus, Dow Jones Newswires; 215-656-8289; peter.loftus@dowjones.com