By Stephen Leeb, The Complete Investor

Alexion Pharmaceuticals (ALXN) had set the bar so high that even its recent strong results (third-quarter revenue growth of 44%) weren't considered good enough.

The results were seen as somewhat light given that they included revenues from sales of the company's Soliris drug to treat aHUS, a rare life-threatening disease that mainly affects children and for which there is no other approved treatment. Until being expanded for use with aHUS, Soliris was used solely for the rare and deadly blood disease PNH.

Alexion's marketing/education outreach efforts have raised awareness of PNH among doctors, helping the company add new patients at a rapid clip as more people are tested for and diagnosed with the disease. The company is making a similar push to increase awareness of aHUS.

Beyond its core markets of the U.S., Europe, and Japan, Alexion has been moving into emerging countries like Brazil and Turkey, with Korea and Russia expected to further add to growth next year.

Alexion reports a "steady" trend of patient additions, though it does not report specific numbers. Soliris also is close to approval for STEC-HUS, a rare blood disorder that can lead to progressive organ damage.

Trial data have shown sustained benefit, and submission for FDA approval is expected in mid-2013, with launch possible by 2014. Peak sales of Soliris for STEC-HUS could be several hundred million dollars per year.

Looking further ahead, Soliris has shown good clinical trial results for NMO, an extremely rare autoimmune disease with no current treatment that chronically attacks the neurological system and leads to paralysis, blindness, and premature death.

In the recently completed phase 2 trial,12 of the 14 patients with severe relapse NMO who received 12 months of Soliris treatment were free of attacks.

A larger trial is planned for next year. Soliris is also in trials for kidney transplant rejections and for myasthenia gravis, an autoimmune disorder causing severe muscle weakness.

Beyond Soliris, Alexion has other early-stage therapies in the works. Its asfotasealfa drug has shown promising early Phase 2 trial data for HPP. This rare, inherited metabolic disease results in a lifelong deficiency of a critical enzyme, leading to a progressive deterioration of various body parts.

Daily injections of the drug in teens and adults appear to significantly reduce the harmful substrates that accumulate because of the enzyme deficiency.

A natural history study is ongoing of infants inflicted with HPP, half of whom do not survive past the first year, and a new six-month placebo-controlled trial is expected to begin next year. Regulatory filing to treat pediatric patients could occur by 2014.

With the potential for continued market penetration and expansion of Soliris for PNH and aHUS, we continue to rate the stock a buy.

Given the potential for continued market penetration and expansion of Soliris, the company's impeccable track record in executing its marketing plans, and several potential growth catalysts in its pipeline, we view the recent decline as a buying opportunity.

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