EYDELTO, known generically as fostemsavir, is an antiretroviral medication used in the treatment of HIV/AIDS. It is specifically designed for adults with multidrug-resistant HIV-1 infection for whom it is otherwise difficult to construct an effective antiviral regimen due to resistance, intolerance, or safety considerations. EYDELTO works by attaching itself to the gp120 protein on the surface of the HIV virus, thereby blocking the virus's ability to attach to and enter human immune cells (CD4 cells). This mechanism is distinct from other antiretroviral drugs, making EYDELTO a valuable option in the management of HIV, particularly in cases where the virus has become resistant to multiple other medications. It is typically used in combination with other antiretroviral medications to effectively manage HIV infection and prevent the progression to AIDS.