Pen on a business contract
Kanuma brought in just $28.4 million in the third quarter of 2019, a 12% increase year over year, but nowhere near the scale needed to hit the blockbuster targets it originally carried. (SARINYAPINNGAM/iStock/Getty Images Plus)

Deal size:
$8.4 billion
Date announced: May 6, 2015

Cash-rich with its rare-disease drug Soliris galloping through the market, in 2015, Alexion decided to go all-in on another blockbuster hopeful. Its choice? Synageva and its late-stage candidate Kanuma. Alexion paid a steep price in that $8.4 billion deal—a whopping 135% premium on Synageva's stock price—and whiffed big time.

In the third quarter, Kanuma brought in just $28.4 million in sales—a 12% increase from the same quarter last year, but nowhere near the peak $1 billion to $1.5 billion sales some analysts touted at the time of the acquisition.

Announcing the pickup, Alexion's then-CEO David Hallal called Synageva an "ideal strategic and operational fit" for the drugmaker.

"With strong ongoing Soliris growth in PNH and aHUS worldwide, and the anticipated 2015 global launches of Strensiq and Kanuma, we will accelerate and diversify our revenue growth," Hallal said. "We are excited to create the most robust rare disease pipeline in biotech across a range of therapeutic modalities."

An Alexion spokesperson could not be reached for comment for this report.

Analysts were also on board with the acquisition at the time. Nomura equity analyst Ian Somayia called the drug a "potential blockbuster," and said the aggressive purchase price pointed to Alexion potentially boosting the drug's list price.

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"Strategically, we get the rationale for the deal, and we think that it makes sense given Alexion's global commercial infrastructure and focus on ultra-orphan diseases," Barclays analysts said in a note to investors. "In our view, Kanuma could be a $1 billion to 1.5 billion peak (worldwide) sales opportunity and SBC-103 for MPS3B is in phase 1/2 development."

Barclays did show some skepticism, however, saying it could take years for Kanuma to hit that peak.