NEW YORK (CNN/Money) - Bristol-Myers Squibb, which reports earnings on Thursday, is feeling the familiar sting of patent loss, though analysts said the company's robust pipeline could make it a promising long-term investment.

Bristol-Myers enjoyed growing sales for some of its key products last year and on March 30 had Baraclude, a treatment for hepatitis B, approved by the FDA. But last year's patent expiration on chemotherapy drug Paraplatin is expected to make its mark on first quarter earnings, analysts say, and the looming loss of Pravachol will make things worse for the company.

"It's the same old story of patent expiration," said Scott Henry, an analyst for Oppenheimer & Co. who rates the company a "neutral." Referring to the loss of Paraplatin, a chemotherapy drug with $673 million in 2004 sales, Henry said, "It's going to be $160 million [in quarterly sales] that's going to go away."

Bristol-Myers is expected to report a 10 percent decline in revenue and a 18 percent drop in earnings per share for the first quarter, according to a Thomson Financial consensus. Bristol-Myers (up $0.07 to $25.76, Research) stock prices have been volatile over the last 12 months, but are trading about where they were a year ago.

The loss of Paraplatin is "weighing on the company," but pales in comparison to the impending expiration of Pravachol in 2006, said John Boris, analyst for Harris Nesbitt with a "neutral" rating for the company. Pravachol, a cholesterol lowering drug, made $2.6 billion in sales last year, out of $19.4 billion total sales for the company.

"You're just coming out of Paraplatin and you get whacked in the stomach again with Pravachol," said Boris.

In addition, Boris said ongoing litigation involving the company's top-selling drug Plavix, an anti-stroke blood thinner with $3.3 billion in 2004 sales, should concern investors.

"If Plavix goes, so does the dividend," said Boris.

And sales for newly-approved Baraclude won't pick up the slack, said Boris, who expects annual revenues for that hepatitis B treatment to peak at $200 million in 2010. "[Baraclude] doesn't really move the needle," said Boris.

The company's pipeline is promising, but investors will have to wait years before any of those drug candidates become "billion dollar pillars," said Boris. Assuming FDA approval, Boris expects the diabetes treatment Muraglitazar and the rheumatoid arthritis drug Abatacept to be making $1 billion in global sales by 2010.

When analysts speak favorably of Bristol-Myers, they give a nod to the pipeline. Richard Evans, analyst for Bernstein & Co. who rates the company a "buy," reported that the company's pipeline is undervalued compared to competing drug companies, presenting the company as an attractive possibility for acquisition.

"Bristol's pipeline remains cheap versus peers," wrote Evans in a report Wednesday. "We think it would be cheaper for a competitor to buy the pipeline than to recreate it."