A novel method for producing an immunogenic composition or vaccine comprising inactivated lentivirus, in particular inactivated HIV, wherein producer cells constituvely producing lentivirus particles are provided, the lentivirus particles are produced by these producer cells in the presence of an antiretroviral (ARV) agent which is an inhibitor of the IN-LEDGF/p75 interaction, the inactivated lentivirus is recovered and formulated in a pharmaceutically acceptable vehicle or carrier. The invention also relates to immunogenic compositions or vaccines and to methods for the therapeutic or prophylactic treatment of a mammal, especially a human, and various therapy combinations involving the administration of said immunogenic compositions or vaccines.
