EMD Serono, Inc., a subsidiary of Merck KGaA, Darmstadt, Germany, and Pfizer Inc. announced that the United States Food and Drug Administration(FDA) approved Rebif(R) Rebidose(R) (interferon beta-1a), a single-use auto-injector for the self-administration of Rebif, a disease-modifying drug used to treat relapsing forms of multiple sclerosis (MS).