Just looking at the top five selling drugs, US sales of more than US$10 billion will be open to competition by the generics industry.

Key patent expiries, according to data from EvaluatePharma, include Lipitor (atorvastatin – Pfizer), Zyprexa (olanzapine – Eli Lilly), Levaquin (levofloxacin – Johnson & Johnson), Concerta (methylphenidate – Johnson & Johnson) and Protonix (pantoprazole – Pfizer). These patent expiries, while being very good news for the generics industry and patients could deal a major blow to some of the largest pharmaceutical companies.

In 2010, with US$10.8 billion in worldwide sales, Lipitor accounted for 15.8% of Pfizer’s total revenue. While in 2010, Zyprexa’s worldwide revenues were just over US$5 billion, or nearly 22% of Eli Lilly’s full year sales.

Once drugs lose patent protection, lower-price generics rapidly gain market share, often siphoning off as much as 90% of sales. Benefits to patients are substantial, with generics averaging about 30% of the price of the brand-name originals.

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