No. 4: Questcor Pharmaceuticals (QCOR)
Once again, selling a high-priced drug to relatively small groups of patients proves to be a winning formula for Questcor. Sales of H.P. Acthar Gel are surging and so are Questcor's profit.
The stock: This is the second consecutive year that Questcor lands on the list of best-performing biopharmaceutical stocks. Questcor shares are 197% since Dec. 16. Earnings are expected to double this year over 2010 and grow another 60% in 2012.