Correction: Leonard Bell, not David Halal, was the CEO of Alexion at the time of the Synageva acquisition.

When Alexion Pharmaceuticals (ALXN) paid $8.4 billion to acquire Synageva Biopharma in May 2015, then CEO Lenny Bell told investors the high price tag was justified because Kanuma, Synageva's lead rare disease drug, would become a billion-dollar product.

Behind Kanuma in the Synageva deal, Alexion was also getting SBC-103, a second rare disease drug that would bolster the company's pipeline, Bell said.

Less than two years later, Alexion is not getting the bang for the mega-bucks it put up for Synageva. Bell is no longer the CEO of Alexion. He was replaced by David Halal, who was then fired in December.

On Thursday, Alexion reported Kanuma sales of $11 million in the fourth quarter. For all of 2016, the drug delivered $29 million in sales.

After more than one year on the market, Kanuma, at a run rate of less than $50 million per year, is impossibly far from the billion-dollar potential promised by Alexion at the time of the acquisition.

And now SBC-103 is also a bust. Thursday, Alexion said it was shuttering future clinical development on the drug and taking an $85 million impairment charge.

The Synageva acquisition was supposed to help Alexion diversify its portfolio of rare disease drugs and lessen the reliance on Soliris for future growth. Instead, the $8.4 billion spent on Synageva was largely wasted.

Earnings guidance for 2017 was soft. Alexion is forecasting total revenue in the range of $3.4 billion to $3.5 billion versus the consensus of $3.55 billion. Soliris sales guidance of $3.025 billion to $3.1 billion is in-line but expected sales for the metabolic franchise -- Strensiq and Kanuma -- are weaker than expected.

The company's projection for 2017 non-GAAP earnings of $5-$5.25 per share is also short of $5.55 per share consensus.

Alexion shares opened Thursday up 3.5% to $136, because investors were largely expecting the company to deliver weak financial guidance. Wall Street tends not to spend a lot of time being introspective about deals gone bad.

But Alexion shares are down 20% since announcing the Synageva acquisition compared to a 13% fall in the Nasdaq Biotechnology Index during the same time frame. On that score, Alexion shareholders are still being punished for a classic case of paying too much and delivering too little.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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