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.
