Only a select few specialty pharmaceutical companies are actually cash flow-positive; fewer still have enough cash on hand to account for a majority of their share price. With far more cash on hand than debt, and a profitable drug already on the market, ViroPharma (Nasdaq: VPHM) should pique any investor's interest.

Earlier today, ViroPharma released mixed first-quarter financial results. Sales of its oral antibiotic drug Vancocin rose 3.9% year over year, but operating income got crushed by more than 40%. ViroPharma spent those funds to ramp up its sales force and advance its lead pipeline candidate through continued phase 3 testing.

Nonetheless, earnings per share still totaled $0.22 for the quarter. Considering that the reasons behind the increased spending will propel near-term future growth of Vancocin sales, and potentially get ViroPharma's second drug on the market, the extra expenditures seem understandable, if not desirable.

ViroPharma guided that stem-cell-transplant prophylactic treatment Camvia will produce the phase 3 data needed to file a marketing application in 2009. Not all of ViroPharma's pipeline will progress so nicely, though. Earlier this month, ViroPharma and partner Wyeth (NYSE: WYE) announced that they were discontinuing testing of hepatitis C antiviral drug HCV-796.

There were no new developments on ViroPharma's conference call today about how the company plans to spend its nearly $600 million cash stockpile, except for the usual statements about how it was looking at multiple acquisition opportunities. Speaking of this cash, ViroPharma's CFO deserves a raise. This is one of the few drugmakers with sizeable amounts of cash on its balance sheet to feel no direct effects from ongoing troubles in the auction-rate securities markets. 

Even though ViroPharma lost one of its four potential drugs this month, there's still a lot to like about it. An investment here still comes with a lot of risk, since the generic axe on lead drug Vancocin could fall at any time. But as investors have gotten comfortable with the possibility that this generic competition might be further delayed, ViroPharma's shares have risen. For risk-tolerant Fools willing to gamble against any sudden plunge in the shares, ViroPharma still makes an exciting biotech investment.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool's disclosure policy lives dangerously so you don't have to.