In March 1999, Genpharm Inc, advised it was seeking regulatory approval in Canada to market generic omeprazole capsules and made allegations with respect to AstraZeneca's patents. AstraZeneca responded by filing lawsuits that disputed Genpharm's allegations. In October 2000, the Canadian regulatory authority rejected Genpharm's regulatory application for its generic omeprazole product.

For several years, various companies have sought to market generic omeprazole in Canada. AstraZeneca has successfully asserted its patent rights for its Losec® product and no generic product has reached the market to date.

AstraZeneca is a major international healthcare business engaged in the research, development, manufacture and marketing of ethical (prescription) pharmaceuticals and the supply of healthcare services. It is one of the top five pharmaceutical companies in the world with healthcare sales of over $15 billion and leading positions in sales of gastrointestinal, oncology, anaesthesia including pain management, cardiovascular, central nervous system (CNS) and respiratory products.