With the Nasdaq biotech index down 13% for 2006, most biotech investors are having a bad year. Not so for investors in Gilead Sciences (NASDAQ:GILD); shares of the biopharmaceutical company have risen more than 9% since the year began.

Yesterday, Gilead released results from its busy and acquisitive second quarter. Just last month, the company purchased a manufacturing facility for $144 million. Two days ago, Gilead announced its purchase of the remaining shares of privately held Corus Pharmaceuticals for $365 million.

What did Corus bring to Gilead? It's tough to tell, since Corus was a private company, but its research focused on respiratory and infectious diseases. The company's lead drug is in two phase 3 trials for the treatment of cystic fibrosis. If the results of those trials, expected in early 2007, are favorable, an NDA filing could follow in the second half of next year. Gilead said it would release more information about Corus in the future, which will hopefully make it much easier to handicap the quality of this acquisition.

Just last week, Gilead announced that the FDA approved a more convenient combination of its antiretroviral blockbuster Truvada and Bristol-Myers Squibb's (NYSE:BMY) Sustiva. The new Atripla is a single-dose pill of the two companies' drugs. Since Atripla won't be selling for a premium price compared to Truvada and Sustiva separately, I don't see huge sales growth potential relative to the cannibalizing of Truvada sales that will occur.

Gilead's two revenue-growth drivers are its HIV products and royalties on Roche's sales of Tamiflu. HIV product sales increased 38% to $475 million year over year, and Tamiflu royalties were up more than 100% to $73 million in the same period. Together, Tamiflu and the HIV products represent about 80% of Gilead's $685 million in revenues.

For 2006, Gilead also raised its HIV franchise revenue guidance for the year by about $100 million, to $1.95 billion-$2 billion. If the company can pull this off, it would represent roughly 40% year-over-year growth for its flagship products.

At the moment, Gilead currently holds roughly $3.3 billion in cash. With two acquisitions in the past month, the company has shown that it is not afraid to open its wallet. I wouldn't be surprised to see Gilead attempt a few more purchases in the near future to restock its drug pipeline.

Trading at around 28 times 2006 EPS estimates, and with 40% growth expected for its HIV franchise, Gilead offers tempting value -- assuming it makes smart use of that cash sitting on the balance sheet.

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Fool contributor Brian Lawler does not own shares of any company mentioned above. He welcomes your feedback at blawler@utk.edu. The Fool has a disclosure policy.