By Peter Loftus

Of Dow Jones NEWSWIRES

Bristol-Myers Squibb Co. (BMY) reported a 12% increase in first-quarter profit, as rising sales of cancer drugs helped offset a decline in the company's top-selling anti-clotting drug, Plavix.

The New York-based drug maker's earnings slightly exceeded Wall Street estimates, and the company reaffirmed its earnings forecast for full-year 2012.

Bristol-Myers is bracing for a steep decline in sales of Plavix--which the company co-markets with Sanofi (SNY)--after the drug loses U.S. market exclusivity in May, triggering the launch of lower-priced generic equivalents of the drug.

The company hopes to offset the Plavix patent loss with rising sales of newer drugs, and the potential introduction of new drugs with big commercial potential.

Bristol's research-and-development efforts have been relatively productive in recent years, including last year's launch of skin-cancer drug Yervoy. Bristol hopes to keep the momentum going this year, as it awaits a U.S. regulatory decision by June 28 on Eliquis, a proposed new treatment co-developed with Pfizer Inc. (PFE) to prevent strokes in people with a heart-rhythm disorder that analysts believe has multi-billion-dollar sales potential.

Bristol also is developing potential new treatments for hepatitis C that have shown promise in clinical testing.

Bristol's recent success followed a strategy launched in 2007 to cut costs, shed non-pharmaceutical assets and use the proceeds to pursue acquisitions and license deals to bolster its research pipeline.

"This first quarter performance continues to demonstrate our ability to balance delivering strong financial results in the short-term with positioning the Company for long-term success," Chief Executive Lamberto Andreotti said in a press release.

For the quarter, Bristol reported a profit of $1.1 billion, or 64 cents a share, up from $986 million, or 57 cents a share, a year earlier. The latest quarter exceeded the mean estimate of analysts surveyed by Thomson Reuters by a penny per share.

Gross profit margin as a percentage of net sales was 75.2% in the quarter, versus 73.2% a year earlier.

First-quarter sales rose 5% to $5.25 billion. U.S. sales rose 6%, while non-U.S. sales were up 2%.

Sales of Plavix declined 4% to $1.69 billion. The drug is expected to lose U.S. exclusivity May 17, after which Bristol foresees a substantial sales decline. The drug already has experienced generic competition in some markets outside the U.S.

Combined sales of hypertension drugs Avapro and Avalide, which recently lost market exclusivity, declined 29% to $207 million.

Sales of antipsychotic Abilify were roughly flat at $621 million. Sales of cancer drugs Erbitux and Sprycel increased. Sales of Yervoy, which was approved by the Food and Drug Administration in late March 2011, were $154 million.

Bristol said it continues to expect 2012 earnings of $1.90 to $2 a share. The mean Thomson estimate is $1.97 a share.

--By Peter Loftus, Dow Jones Newswires; +1-215-982-5581; peter.loftus@dowjones.com