"This portfolio includes process, method of use and additional substance patents with expiration dates ranging from 2009 through to 2019. In addition to these patents Nexium has data exclusivity valid to 2010 in major European markets." A second hearing is scheduled for March 7 on another patent issue involving Nexium and the company pledged to defend it. "AstraZeneca will defend and enforce its intellectual property rights protecting Nexium," the company said.