The invention relates to an antibody, a fragment or a derivative thereof, for use as an antiretroviral drug targeting a virus belonging to human endogenous retroviruses type W (HERV-W), wherein said antibody, fragment or derivative thereof is directed against HERV-W Envelope protein (HERV-W Env). The invention also relates to a composition comprising said antibody and a retroviral reverse-transcriptase inhibitory drug, for use as an antiretroviral drug targeting a virus belonging to HERV-W.本發明係關於一種抗體、片段或其衍生物,用於作為一種針對屬於人類內源性反轉錄病毒W型(HERV-W)的病毒之抗反轉錄病毒藥,其中該抗體、片段或其衍生物係針對HERV-W封套蛋白質(HERV-W Env)。本發明亦係關於一種組成物,其包含該抗體及反轉錄病毒的反轉錄酶抑制藥,用於作為針對屬於HERV-W的病毒之抗反轉錄病毒藥。