Shares of Amgen fell nearly 3 percent in late trading on Tuesday following a weaker-than-expected first-quarter earnings report from the world’s biggest biotech company.

Amgen, based in Thousand Oaks, said net income fell 25 percent to $1.07 billion,or $1.40 per share, down from profits of $1.43 billion, or $1.88 per share, a year earlier. The 2013 first-quarter results benefited from a large tax benefit. Revenue grew seven percent to $4.52 billion, slightly below Wall Street expectations.

Amgen cited rising costs and weaker sales for its arthritis drug Enbrel for the lackluster earnings. The company said it still expects full-year profits of $7.90 to $8.20 per share for 2014 on revenue of $19.2 billion to $19.6 billion. The Associated Press cited analysts from FactSet as expecting earning of $8.15 per share on revenue of $19.2 billion.

Shortly before the market close on April 22, shares were trading at $116.03, down $3.27 per share. Prior to the earnings release, the shares closed up more than $2 for the day at $119.30.
According to an Amgen news release, sales improvements were led by Neulasta and Neupogen, which boost infection-fighting white blood cells, with combined revenue of $1.38 billion. Enbrel,

Amgen’s second-biggest seller, fell 5 percent to $988 million while Prolia, a relatively new treatment for osteoporosis, jumped 38 percent to $196 million.
Amgen pinned the lower profits on increased research and development spending, due largely to its acquisition last year of South San Francisco-based Onyx Pharmaceuticals.

“Strong underlying demand for our products and growth in adjusted operating income make us confident in our full-year growth outlook,” CEO Robert Bradway said in an earnings press release.  “We continue to advance our robust late-stage pipeline.”