(Reuters)—Jacobus Pharmaceutical Co Inc on Monday won U.S. approval for the first drug to treat children with Lambert-Eaton myasthenic syndrome, a rare autoimmune disorder. The drug, Ruzurgi (amifampridine), was approved for use in patients ages 6–17, the according to the U.S. Food and Drug Administration (FDA). Lambert-Eaton myasthenic syndrome (LEMS), which affects about three people…