(MONEY Magazine) – In April we called Genentech "the brightest star in the [biotech] sector." Our confidence was vindicated in May, when shares of Genentech (DNA), the second-largest biotech, shot up a whopping 45% in a single day. Investors were responding to a study that showed that Avastin, a Genentech anticancer drug that's still in clinical trials, extended the lives of patients with colon cancer. The good news about Avastin, which works by blocking the growth of blood vessels that feed cancerous tumors, was the second boost Genentech received in May. Earlier in the month, an FDA panel approved the asthma treatment Xolair. Both Xolair and Avastin could be on the market by 2004. "No one in biotech has a better track record of developing drugs," says Jim Fiore, president of biotech investment firm Life Science Group. After its recent surge, Genentech trades for a pricey 52 times trailing earnings. Given the volatility of the biotech sector, it's best not to start buying the stock. But those who own Genentech should hold tight: Earnings are expected to grow 22% a year over the next five years. --ARAVIND ADIGA