Humanized mice reconstituted with human lymphoid cells provide rapid, reliable, reproducible experimental systems for testing the efficacy of Obefazimod in vivo. In the initial setting, SCID mice are reconstituted with PBMCs and then infected with the HIV-1 strain JR-CSF. Mice are treated twice a day (b.i.d) for 15 days by oral gavage with 20 mg/kg of Obefazimod. Measures of viral RNA show that the oral treatment with Obefazimod is able to significantly reduce the viral load over a period of 15 days of treatment. FACS analysis of blood samples show that treatment with Obefazimod prevents depletion of CD4⁺ cells following infection of reconstituted mice and thereby restores the CD8⁺/CD4⁺ ratio back to that of non-infected mice^[1].