The maker of "orphan" drugs for rare diseases may be a takeover target, Reuters said, citing sources close to several drugmakers. Big Pharma is interested in orphan drugs as patents on their blockbusters expire. No deal is imminent, and ViroPharma (VPHM) hasn't said it's for sale, the report said, but it's attracting interest because of its strong pipeline. ViroPharma declined to comment. Its shares rose 6.3% to 28.87 after hitting 30.89 intraday.