With biopharma assets getting bid up so much nowadays, thanks to their resistance to future generic competition, any drugmaker with an approved biologic therapy should be on investors' watch lists. Yesterday, one such biotech, Alexion Pharmaceuticals (Nasdaq: ALXN), presented at the Wachovia Healthcare Conference, providing an opportunity to reflect on where Alexion stands in the biopharma sector with its lead drug.

In March, Alexion received FDA marketing approval for Soliris, which is the only approved treatment for paroxysmal nocturnal hemoglobinuria, a very rare blood disorder that affects 8,000 to 10,000 people in North America and Europe. In June, the European Union regulatory authorities approved Soliris as well.

Alexion owns the worldwide rights to Soliris, but it may have to pay a small royalty to PDL BioPharma (Nasdaq: PDLI), depending on the outcome of a patent-infringement lawsuit PDL filed. By the end of the third quarter, Alexion had only a few hundred patients using Soliris worldwide, but the drug still generated $21.8 million in sales, up more than double from the $9.8 million it brought in during its launch in the second quarter.

Soliris is a monoclonal antibody. It's now Alexion's main clinical-stage pipeline candidate, after another biologic that it promoted with partner Procter & Gamble (NYSE: PG) failed in phase 3 testing back in 2006. That drug was intended to be a treatment in conjunction with coronary artery bypass graft surgery.

Soliris sales should experience some serious growth in 2008. Alexion's priority for the year is to help doctors find and diagnose patients who might benefit from Soliris -- because finding them is half the battle with this ultra-rare disorder -- and then getting them on the drug. In Europe, Soliris is only on the market in the U.K. and Germany, but sales in France, Italy, and Spain are expected to commence in the middle of the year. Alexion is also awaiting a Soliris marketing decision in Australia and has a phase 3 study under way in Japan to help get approval there as well.

Alexion suffered a $14 million non-GAAP net loss in the third quarter last year and is pretty much a one-drug-wonder biopharma right now. With $126 million in cash and a $2.4 billion market capitalization, shares of Alexion are a little too expensive for my conservative tastes right now, but other companies, such as BioMarin Pharmaceuticals (Nasdaq: BMRN) and Shire (Nasdaq: SHPGY), which bought Transkaryotic Therapies, have shown how successful developing niche orphan drugs can be. So don't leave Alexion off your watch list.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has an A-plus disclosure policy.