WASHINGTON (AP) — Shares of Alexion Pharmaceuticals Inc. jumped Friday on media reports that Swiss drugmaker Roche is considering a buyout of the smaller Connecticut-based drugmaker.

THE SPARK: Bloomberg News reported Friday that Roche has been talking to Alexion for months about a possible takeover, citing unnamed sources with knowledge of the situation. If Roche follows through on the purchase it would be the company’s largest acquisition since its $48.6 billion buyout of California biotech company Genentech in 2009.

A spokeswoman for Roche said the company would not comment on “market rumors or speculation.” Calls placed to Alexion Pharmaceuticals were not immediately returned.

THE BACKGROUND: Alexion markets only one drug, the injectable treatment Soliris. It was first approved in 2007 as a treatment for paroxysmal nocturnal hemoglobinuria, or PNH, which causes a breakdown of red blood cells and leads to anemia. In late 2011 it was approved as a treatment for atypical hemolytic uremic syndrome, or aHUS, which often leads to kidney failure and death.

Soliris had 2012 sales of $1.13 billion, up from $783 million the prior year

SHARE ACTION: Shares of Cheshire, Conn.-based Alexion rose $12.82, or 12.6 percent, to $114.26. Earlier during the session shares hit $125.65, an all-time high.