generic competition in the U.S. in May 2011, as well as the loss of exclusivity in many major European markets in February 2012, and lower revenues for Spiriva in certain European countries, Canada and Australia due to the expiration of our collaboration with BI in those countries, partially offset by the strong performance of Enbrel and Rebif in the U.S. We expect that the Aricept 23mg tablet will have exclusivity in the U.S. until July 2013. See the “The Loss or Expiration of Intellectual Property Rights” section of this Financial Review for a discussion regarding the expiration of various contract rights relating to Aricept, Spiriva, Enbrel and Rebif. Eliquis (apixaban) has been jointly developed and commercialized by Pfizer and Bristol-Myers Squibb (BMS). In 2012, Eliquis (apixaban) was approved to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation in the 27 countries of the EU, plus Iceland and Norway, Canada, Japan and the U.S., and it was launched for that indication in the U.S. in January 2013. The two companies share commercialization expenses and profit/losses equally on a global basis.

• Embeda—WemetwiththeFDAinMay2012todiscussourproposalforreintroductionofEmbedatothemarket.Therequiredstability programs are underway, and we are working toward a submission with the FDA in the first half of 2013.

See Notes to Consolidated Financial Statements—Note 17. Commitments and Contingencies for a discussion of recent developments concerning patent and product litigation relating to certain of the products discussed above.

Research and Development

Research and Development Operations

Innovation is critical to the success of our company and drug discovery and development is time-consuming, expensive and unpredictable, particularly for human health products. As a result, and also because we are predominately a human health company, the vast majority of our R&D spending is associated with human health products, compounds and activities.

The following table provides additional information by operating segment about our research and development expenses (see also Notes to Consolidated Financial Statements––Note 18. Segment, Geographic and Other Revenue Information):

Our human health R&D spending is conducted through a number of matrix organizations––Research Units, within our Worldwide Research and Development organization, are generally responsible for research assets (assets that have not yet achieved proof-of-concept); Business Units are generally responsible for development assets (assets that have achieved proof-of-concept); and science-based and other platform- services organizations.

We take a holistic approach to our human health R&D operations and manage the operations on a total-company basis through our matrix organizations described above. Specifically, a single committee, co-chaired by members of our R&D and commercial organizations, is accountable for aligning resources among all of our human health R&D projects and for ensuring that our company is focusing its R&D resources in the areas where we believe that we can be most successful and maximize our return on investment. We