Indication: Indicated for human immunodeficiency virus-1 (HIV-1) infection in heavily treated adults with multidrug-resistant infection failing their current antiretroviral therapy (ART) regimen. It is used in combination with other ART drugs.
Mechanism: First CD4-directed post-attachment HIV-1 inhibitor approved by the FDA. The drug’s binding specificity to domain 2 of CD4 allows ibalizumab to block viral entry into host cells without causing immunosuppression.
First dose (single loading dose): 2000 mg IV.
Maintenance dose: 800 mg IV every 2 weeks.
Approval was based on the MB-301 phase 3 trial. MB-301 was a single arm, 24-week study of ibalizumab plus optimized background regimen (OBR) in treatment-experienced patients infected with multidrug resistant HIV-1.
The following study results were observed at 24 weeks:
43% of study participants achieved viral suppression <50 copies/mm3 and half <200 copies/mm3.
While 60% of those with a baseline CD4 count of >50 cells/mm3 achieved undetectable viral load, this fell to <20% for those with lower CD4 counts.
55% of participants had at least a 1 log decrease and 48% had at least a 2 log decrease in HIV RNA; the average reduction from baseline was 1.6 log.
The overall average CD4 cell gain was 48 cells/mm3, but this differed according to baseline level: people who started with at least 50 cells/mm3 saw a mean gain of about 75 cells/mm3, while those with lower baseline levels gained an average of 9 cells/mm3.
Lewis S, Fessel J, Emu B, et al. Long-acting ibalizumab in patients with multi-drug resistant HIV-1: A 24-week study. Presented at the 2017 Conference on Retroviruses and Opportunistic Infections. February 13-16, 2017. Seattle, WA.
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Cite this: Mary L Windle. FDA New Drug and Biologic Approvals, 2018 Midyear Review - Medscape - Aug 01, 2018.