Toronto-based Apotex said its version of Lipitor, which generates revenue of C$1.2bn a year for Pfizer in Canada, is a different crystal form of the drug and hence does not infringe on of any of the US drugmaker’s patents.
Pfizer rejected Apotex’ claim that its drug is bioequivalent to Lipitor, telling Reuters that it cannot be considered an identical "interchangeable" product until drug formularies maintained by Canadian provinces declare it so.
Spokeswoman Sally Beatty said that the firm plans to sell its own non-branded version of the drug in Canada through its established products business unit but did not say when it would launch the generic.
The next few years are likely to see Pfizer face more and more challenges to its Lipitor franchise which is set to start losing patent protection in key markets in 2011.