Question: When was the American pharmaceutical corporation headquartered in New York City, with its research headquarters in Groton, Connecticut took over Clorets?
Sentence (from "Alexion Pharmaceuticals"): Alexion Pharmaceuticals Inc. is an American pharmaceutical company best known for its development of Soliris, a drug used to treat the rare disorders atypical hemolytic uremic syndrome (aHUS) and paroxysmal nocturnal hemoglobinuria (PNH).
Relevant evidence: No