THOUSAND OAKS, Calif. ( TheStreet) -- Amgen ( AMGN) reported a 13% increase in adjusted second-quarter earnings Monday ahead of an important Food and Drug Administration meeting for its osteoporosis drug denosumab next month.

The company also raised 2009 earnings guidance and announced a marketing partnership with drug giant GlaxoSmithKline ( GSK) to sell denosumab in Europe.

Net income for the second quarter totaled $1.27 billion, or $1.25 a share, compared to net income of $906 million, or 84 cents a share, in the year-ago quarter. Income in the quarter was partially bolstered by a one-time tax benefit, the company said.

On an adjusted basis, Amgen earned $1.29 a share, above the Street's consensus estimate of $1.16 a share, according to Thomson Reuters.

June quarter revenue fell 1% year over year to $3.76 billion, but still ahead of the consensus forecast of $3.58 billion.

Amgen raised guidance on 2009 adjusted earnings to a range of $4.80 a share to $4.95 a share. Current Street consensus is at $4.57 a share. The company also said revenue for the year was coming in at the high end of its previously stated guidance range of $14.4 billion to $14.8 billion.

Amgen's second-quarter earnings report comes as the FDA is set to convene an advisory panel meeting on Aug. 13 to review the company's experimental osteoporosis drug denosumab. A key issue to be debated at the meeting will be denosumab's safety with a particular focus on any association between the drug and an increased risk of infection.

Denosumab is the most important new drug to come out of Amgen's research labs in years and is a key to the company's future growth as sales of its flagship anemia drugs, Epogen and Aranesp, have flagged in recent years.

Monday, Amgen said Glaxo will co-market denosumab for osteoporosis in Europe I in exchange for a $120 million upfront payment and ongoing royalties based on the product's sales.

Returning the the June quarter recap, worldwide sales of the anemia drug Aranesp totaled $693 million, a 16% decrease year over year but still above investor expectations Aranesp sales in the U.S. fell 21% year over year to $338 million.

Aranesp sales have fallen over the past two years due new safety-related label restrictions mandated by regulators in the U.S. and Europe. Less expensive copycat versions of Aranesp - so-called biosimilars - are also being marketed by competitors in Europe.

Sales of Enbrel, used to treat psoriasis, rheumatoid arthritis and other autoimmune diseases, rose 7% in the first quarter to $899 million. Analysts were looking for sales of around $825 million.

The rebound in second-quarter Enbrel sales comes after the drug posted disappointing sales in the first quarter due to the weak economy. Earlier this month, Abbott Labs ( ABT) also posted stronger sales of its rheumatoid arthritis drug Humira.

Turning to other products, Amgen reported $638 million in worldwide sales of Epogen, the company's other anemia drug. Worldwide sales of the infection-fighting drugs Neupogen and Neulasta totaled $1.16 billion million in the quarter.

Amgen shares closed Friday at $60.77.

-- Reported by Adam Feuerstein in Boston
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