"We had solid revenue growth in the first quarter," said Kevin Sharer, chairman & CEO. "Prolia continues to build momentum and XGEVA is off to a strong start. Our operating costs grew in the quarter as we absorbed the new U.S. Healthcare Reform Excise Fee, invested in launches of Prolia and XGEVA and in clinical development programs transitioning to Phase 3."
Adjusted EPS and adjusted net income for the first quarter of 2011 and 2010 exclude, for the applicable periods: stock option expense; certain expenses related to acquisitions and actions to improve cost efficiencies; non-cash interest expense resulting from a change in accounting for our convertible notes; and certain other items. These adjustments and other items are presented on the attached reconciliations.
On a reported basis and calculated in accordance with United States (U.S.) Generally Accepted Accounting Principles (GAAP), Amgen's GAAP diluted EPS were $1.20 in the first quarter of 2011, an increase of 2 percent compared to $1.18 in the same quarter last year. GAAP net income of $1,125 million in the first quarter of 2011 decreased 4 percent from $1,167 million in the first quarter of 2010.
Amgen's first quarter of 2011 financial results were positively impacted by the recently enacted Puerto Rico excise tax associated with the Company's manufacturing operations in Puerto Rico. This excise tax is accounted for as a manufacturing cost that is capitalized in inventory and expensed when the products are sold. For U.S. income tax purposes, a significant portion of the excise tax results in a foreign tax credit that is recognized when the tax is paid. This difference in the timing of recognizing the expense and the applicable tax credit positively impacted the first quarter of 2011 financial results.
Amgen discovers, develops, manufactures, and delivers innovative human therapeutics. A biotechnology pioneer since 1980, Amgen was one of the first companies to realize the new science's promise by bringing safe, effective medicines from lab to manufacturing plant to patient. Amgen therapeutics have changed the practice of medicine, helping millions of people around the world in the fight against cancer, kidney disease, rheumatoid arthritis, bone disease, and other serious illnesses. With a deep and broad pipeline of potential new medicines, Amgen remains committed to advancing science to dramatically improve people's lives.