Despite charges relating to a recent acquisition, biotech giant Amgen Inc. beat Wall Street second-quarter forecasts on Thursday as it reported double digit increases in sales of its drugs to fight anemia, infection and inflammation.

Thousand Oaks-based Amgen’s acquisition of Fremont-based biotech Abgenix Inc. took a significant chunk out of the company’s reported earnings. Charges related to the merger, plus stock-options expenses and other costs, totaled $1.1 billion, reducing net income to $14 million, compared to $1.03 billion, or 82 cents, for the same period a year ago. Sales rose 14 percent to $3.6 billion.

But Amgen said adjusted earnings showed a jump of nearly 12 percent to almost $1.2 billion, or $1.05 a share. The consensus of analysts polled by Thomson First Call had forecast sales of $3.5 billion and adjusted earnings of 94 cents a share.

Sales of Amgen’s top-selling anemia drug Aranesp surged 26 percent to $1.1 billion. Combined sales of Neulasta, used with chemotherapy to fight infection, and an older version called Neupogen rose 12 percent to about $1.1 billion. Sales for Enbrel, which treats rheumatoid arthritis, rose 13 percent to $724 million.

“It’s a really good result,” Geoffrey Porges, an analyst at Sanford C. Bernstein & Co. told Bloomberg News. “People are going to get excited about this name again.”

Amgen shares, which fell 1 percent to $63.92 in regular trading, climbed 4.5 percent in after-hours trading. The company, which released its financials after the market close, has seen its share price fall 20 percent since the beginning of the year.

Amgen acquired Abgenix for $2.2 billion in April to gain full rights to a potential $2 billion-a-year colon cancer treatment called panitumumab. If approved by U.S. regulators as the company expects in September, the drug will be Amgen’s first product to directly fight the cancer, not merely treat its side effects. The company said it plans to market the drug under the brand name Vectibix.