Sales of Kyprolis—which played a key role in the company's 2013 $10.4 billion Onyx Pharmaceuticals acquisition— totaled $94 million, beating StreetAccount expectations for $85 million in sales.
Amgen's osteoporosis drug Prolia saw the biggest increase, with sales up 43 percent year over year, due to stronger volume. Prolia sales totaled $255 million, topping StreetAccount estimates for $238.6 million.
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The company's shares rose as much as 2 percent before easing. (Get the latest quotes for Amgen.)
Amgen posted third-quarter earnings, excluding items, of $2.30 per share, up about 19 percent from the year-earlier period, while sales rose nearly 6 percent to $5.03 billion.
Wall Street had expected the company to hand in earnings of $2.11 a share on roughly $4.96 billion in revenue, according to a consensus estimate from Thomson Reuters.
Amgen expects full-year earnings to finish in the range of $8.45 to $8.55 per share, versus current analyst estimates for $8.42 per share. It sees full-year revenue coming in between $19.80 billion and $20 billion, higher than current forecasts of $19.73 billion.
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The Thousand Oaks, California-based company previously projected adjusted full-year earnings per share of between $8.20 and $8.40 per share.
Adjusted operating income grew 22 percent, year over year, which "reflects strong performance across our business in the third quarter," Amgen CEO Robert Bradway said in a statement. "With regulatory submissions for four new products during the quarter, we are at the beginning of an exciting new product cycle."
On a GAAP basis, the company said net income fell 9 percent, year over year, and was "negatively impacted by pretax charges of $376 million for the restructuring plan announced earlier in the quarter."
Activist investor Dan Loeb of Third Point Capital recently proposed breaking the company up into parts, calling Amgen a "hidden value situation." Amgen leadership acknowledged receiving the proposal, but has not discussed what action, if any, it will take.
The company also plans to lay off roughly 300 employees in December and close its operations in Washington state by the end of 2015, according to The Seattle Times. The move is part of larger restructuring program announced in July to cut costs and focus the company on researching and making new drugs, as its current portfolio faces competition from cheaper generic alternatives.
—CNBC's Robert Ferris contributed to this report.