No surprise, right? Pharmasset's $11 billion ($137-per-share) takeover by Gilead Sciences ( GILD) last month was just icing on Pharmasset's very sweet year. The company's experimental pill PSI-7977, with its potential to eliminate the need for weekly interferon injections from hepatitis C therapy, could soon dominate a $20 billion treatment market. The stock: Pharmasset shares rose a stunning 468% this year, as of Dec. 16. >>To see these stocks in action, visit the Five Drug Stock Winners of 2011 portfolio on Stockpickr. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com. Follow TheStreet on Twitter and become a fan on Facebook.