No one ever said being a biotech company was easy. Biotechnology companies are known for pursuing opportunities that the big boys ignore. That kind of moxie can translate into a drug with no competition and, hence, considerable sales. Sometimes, though, even an approved drug is more trouble than it's worth. Cell Therapeutics (NASDAQ:CTIC) has learned that lesson, but the company still faces some tough times ahead.

The Seattle-based company announced Tuesday that it will sell its only approved drug to Cephalon (NASDAQ:CEPH). Cell Therapeutics unloaded Trisenox, a treatment for a rare form of leukemia, for $70 million in cash, plus up to an additional $100 million based on certain sales and regulatory milestones.

Given the economics of Trisenox, the deal makes some sense. From 2000 until the present, Cell Therapeutics spent $100 million on the medicine, while sales have been just $67 million, according to an interview with the firm's CEO James Bianco in the Seattle Post-Intelligencer. Trisenox sales have continued to grow, but not enough to reverse the company's losses, which amounted to $39.1 million in the first quarter.

With Trisenox off its books, the firm now hopes to focus on getting approval for Xyotax, a form of the widely used cancer drug paclitaxel, which has been modified to improve its water-solubility, lowering its toxicity.

Unfortunately, the Trisenox sale is not likely to provide much breathing room; $30 million from the deal will go to investor PharmaBio Development. Based on the remaining proceeds (excluding potential future payments), and cash and equivalents at the end of the first quarter, Cell Therapeutics will have roughly a year's worth of cash if it achieves its hoped-for $8 million monthly burn rate.

An NDA submission for Xyotax is expected in the first half of 2006, meaning that Cell Therapeutics will probably need to raise cash while it awaits FDA approval. Without an approved drug on the market or the certainty of FDA clearance, the firm won't have an easy time finding investors.

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Fool contributor Brian Gorman is a freelance writer in Chicago. He does not own shares of any companies mentioned in this article.