Ibalizumab: A Review in Multidrug-Resistant HIV-1 Infection

Ibalizumab (Trogarzo (R); ibalizumab-uiyk) is the first monoclonal antibody to be approved for the treatment of HIV-1 infection. As a CD4-directed post-attachment inhibitor, ibalizumab blocks HIV-1 entry into CD4 cells while preserving normal immune function. Ibalizumab, in combination with other antiretroviral(s), is indicated in the USA for the treatment of heavily treatment-experienced adults with multidrug-resistant HIV-1 infection failing their current antiretroviral regimen, and in the EU for the treatment of adults infected with multidrug-resistant HIV-1 infection for whom it is otherwise not possible to construct a suppressive antiviral regimen. In the pivotal phase III TMB-301 trial, ibalizumab significantly reduced the viral load 7 days after being added to a failing antiretroviral regimen. Almost half of all patients achieved an undetectable viral load after 24 weeks of treatment with ibalizumab plus an optimized background regimen, with virological suppression maintained over the longer term (up to 96 weeks) in an expanded access protocol. The drug was generally well tolerated in clinical trials. Although additional studies and long-term post-marketing data are needed to fully determine its efficacy and safety, ibalizumab represents a valuable and much needed treatment option for patients with multidrug-resistant HIV-1 infection.