Law360, New York (June 03, 2010, 2:17 PM ET) -- Patent claims covering methods of treatment; methods of performing certain diagnostic tests; and, increasingly, personalized medicine are common and important parts of patent portfolios developed by biotech and pharmaceutical companies. Patent owners, however, face a difficult hurdle in enforcing this type of claim against potential infringers.

These claims often are not infringed directly until individual physicians, laboratory technicians or even patients carry out the claimed method. For example, a method of treating a particular disease or condition by taking a drug or combination of drugs is...