Merck & Co., Inc. (NYSE:MRK) reported its earnings before opening bell, reporting falling sales but beating analysts’ estimates for earnings. Worldwide sales were reported as $10.7 billion, a decline of 9 percent, which the company attributed to patent expirations and a 2 percent negative impact from foreign exchange.

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Earnings per share, excluding certain items, were 85 cents. Analysts were expecting the company to report earnings of 79 cents on revenue of $11.1 billion. Including costs related to acquisitions, restructuring and other items, the company’s earnings were 52 cents per share.

“Our first quarter performance reflects the challenges of major patent expiries coupled with the impact of currency and other headwinds, said chairman and CEO Kenneth C. Frazier in a statement. “During the quarter, we took focused actions to reach our EPS target while at the same time advancing Merck’s pipeline in our laboratories and through strategic deals and partnerships.”

One of Merck & Co., Inc. (NYSE:MRK)’s newest partnerships is with Pfizer Inc. (NYSE:PFE). Together, the two will develop a medication to treat type 2 diabetes. Trials on the drug are expected to begin this year.

The company’s pharmaceutical sales during the first quarter fell 12 percent to $8.9 billion. The drug maker’s losses of patent exclusivity for Singulair, Maxalt and Clarinex were partially offset by growth in sales of Gardasil, Zostavaz, Remicade, Simponi and Isentress. Its animal health sales were up 2 percent to $840 million, compared to the same quarter a year ago. Consumer care revenue rose 3 percent to $571 million.

The drug maker also revised its full-year guidance down to between $3.45 and $3.55 per share excluding items and between $1.92 and $2.16 including items. The company now expects its full year sales to be 3 to 4 percent below 2012 levels. Merck said it updated its guidance because of pressures on sales that are greater than expected and also losses due to foreign exchange.

This morning Merck also announced a new $15 billion share buyback program. It plans to buy back about $7.5 billion worth of common stock within the next year.

As of the moment of this writing, shares of Merck & Co., Inc. (NYSE:MRK) were down .19 percent in pre-market trading.