Biotechnology’s top performing stocks this year have already given investors envy-inspiring returns, but there’s reason to believe that Calithera Biosciences (NASDAQ: CALA), Aurinia Pharmaceuticals (NASDAQ: AUPH), and Esperion Therapeutics (NASDAQ: ESPR) could still go higher. All three of these companies are run by proven winners, and each is developing drugs that target markets worth hundreds of millions of dollars, or more.