A product patent on a new use may therefore directly extend the life of the existing patent, unless the claims for the original and the new patent refer to specific and separate uses (“use-bound claims”, see below. During one year of artificially extended market exclusivity (based on an invalid patent), the originator company gained more than $1 billion in net sales of the respective pharmaceutical product. Governments may seek to reduce the risk of such lawsuits by limiting patents on product variations unless there are clear and demonstrable grounds to show that the modified substance produces truly new and significant therapeutic impacts.