(treatment of cancer), among others (see the “Analysis of Consolidated Statements of Income: Product Developments––Biopharmaceutical: New Drug Candidates in Late-Stage Development” section of this Financial Review). In December 2009, Prevnar/Prevenar 13 Infant received regulatory approval in a major market and, as a result, we reclassified the asset from IPR&D to Developed Technology Rights and began to amortize the asset.

The fair value of finite-lived identifiable intangible assets will be recognized in our results of operations over the expected useful life of the individual assets.

Some of the more significant estimates and assumptions inherent in the estimate of the fair value of identifiable intangible assets include all assumptions associated with forecasting product profitability from the perspective of a market participant.

Revenue—We use historical, forecast, industry or other sources of market data, including estimates of the number of units to be sold, selling prices, market penetration, market share and year-over-year growth rates over the product’s life cycle.

Cost of sales, Sales and marketing expenses, General and administrative expenses—We use historical, forecast, industry or other sources of market data.

R&D expenses—In the case of approved products, we estimate the appropriate level of ongoing R&D support, and for unapproved compounds, we estimate the amount and timing of costs to develop the R&D into viable products.

Estimated life of the asset—We assess the asset’s life cycle and the competitive trends impacting the asset, including consideration of any technical, legal, regulatory or economic barriers to entry, as well as expected changes in standards of practice for indications addressed by the asset.

Inherent risk—We use a discount rate that is based on the weighted-average cost of capital with an additional premium to reflect the risks associated with the specific intangible asset, such as country risks (political, inflation, currency and property risks) and commercial risks. In addition, for unapproved assets, an additional risk factor is added for the risk of technical and regulatory success, called the probability of technical and regulatory success (PTRS).

The discount rates used in the intangible asset valuations ranged from 9% to 17%, and the estimated cash flows were pro- jected over periods extending up to 20 years or more. For IPR&D assets, the PTRS rates ranged from 4% to 90%. Within this broad range, we recorded approximately $600 million of assets with a PTRS of up to 25%; approximately $500 million of assets with a PTRS of 26% to 50%; approximately $500 million of assets with a PTRS of 51% to 75%; and approximately $12.2 billion of assets with a PTRS above 75% (which includes Prevnar/Prevenar 13 for Infant and Adult). All of these judgments and esti- mates can materially impact our results of operations.

For IPR&D assets, the risk of failure has been factored into the fair value measure and there can be no certainty that these assets ultimately will yield a successful product. The nature of the biopharmaceutical business is high-risk and requires that we invest in a large number of projects as