Helping fuel investors' enthusiasm was Human Genome Sciences whose shares jumped a whopping 395 percent in July on news of positive results for its experimental lupus injectable drug Benlysta, confounding all analysts' expectations and potentially clearing the way for the first new treatment against the inflammatory disease for over 50 years. Patients taking Benlysta plus a standard treatment for one year had reduced symptoms - including pain, rashes and infections - compared with patients taking standard treatment plus placebo. The study involved more than 860 patients in Asia, South America and Eastern Europe. Taking advantage of its strong share value, the company is planning a public offering of over $310 million.

Other major biotech movers included:

- Targacept closed out July up a whopping 338 percent on news that its drug candidate, TC-5214, significantly improved symptoms of major depressive disorder for patients who did not respond to an older drug, Forest Laboratories Inc.'s Celexa. TC-5214 was better than a placebo at improving an overall depression measurement, as well as reducing depression, irritability and severity of illness, and leading to better cognition and overall improvement.

- Orexigen Therapeutics shares jumped 54 percent in July after revealing that Contrave, a longer lasting form of two generic diet drug compounds, helped people lose weight in all three of its major clinical trials. That should clear the way for the San Diego biotech to file for approval to market the drug with the FDA.

- A marquee acquisition also caught the headlines as Medarex's shares soared 90 percent in July on news that Bristol-Myers Squibb was buying the Princeton, New Jersey-based biotech for $2.4 billion, or $16 per share in cash, representing a 90 percent premium. With the acquisition Bristol-Myers Squibb gains full rights to ipilimumab, an experimental drug for metastatic melanoma in late stage testing. The companies together have been developing the drug, which is also being studied in lung and prostate cancers. Bristol also gains rights to seven antibodies in clinical trials under Medarex's sole sponsorship and three other antibodies being co-developed with other partners, and rights to pre-clinical assets in various stages of development by Medarex - in particular, monoclonal antibodies focused in oncology and immunology.