Merck & Co., Inc. announced today that the U.S. Food and Drug Administration (FDA) has accepted the New Drug Application (NDA) for ISENTRESS™ (raltegravir, previously known as MK-0518). Data in the NDA support the proposed use of ISENTRESS in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced patients with evidence of HIV-1 replication despite ongoing antiretroviral therapy (ART).