Alexion Pharmaceuticals (United States)

American biopharmaceutical company at Boston in Massachusetts, founded in 1992 and bought by AstraZeneca in 2021, which now runs as the group's rare disease business. Develops and sells complement inhibitors and other medicines for rare disorders, including eculizumab and ravulizumab for paroxysmal nocturnal haemoglobinuria and atypical haemolytic uraemic syndrome and treatments for myasthenia gravis and metabolic disease, and runs its own research, manufacturing and clinical development.