A new antiretroviral drug, ibalizumab-uiyk (Trogarzo), has been approved by the Food and Drug Administration (FDA) for the treatment of HIV type 1 (HIV-1) in adults with multidrug-resistant HIV-1 who have previously received multiple HIV medications and in whom current therapy is now failing. Patients prescribed ibalizumab-uiyk should also continue to receive their previously failing anti-HIV therapy. Ibalizumab-uiykt is given as an IV infusion.
Ibalizumab-uiyk is a recombinant humanized monoclonal antibody and a CD4-directed postattachment HIV-1 inhibitor. The drug interferes with the entry of HIV-1 virus into host CD4+ cells after the virus attaches to the host cell. Although the drug prevents the virus from entering the host cell, it does not affect CD4-mediated immune functions.
FDA approval of ibalizumab-uiyk was based on a single-arm, multicenter study of 40 subjects previously treated with multiple drugs and infected with multidrug resistant HIV-1. More than 40% of the subjects in the study had a greater than log10 reduction in viral load by week 25 of ibalizumab-uiyk treatment; an increase from baseline in the mean and median number of CD4+ and T cells was also observed.
Ibalizumab-uiyk's label carries a warning that the drug may induce immune reconstitution inflammatory syndrome. This means that if the patient has a preexisting, often subclinical, opportunistic infection, the immune system, now strengthened to mount a defense, may create a strong systemic or local inflammatory response at the site of the infection. This requires the preexisting infection to be identified and treated. Only one patient in ibalizumab-uiyk clinical trials developed this adverse effect. The most common adverse effects, found in 5% or more of those in clinical trials, were diarrhea, dizziness, nausea, and rash.
The drug label includes specific information about reconstitution and administration of ibalizumab-uiyk and should be reviewed carefully. Nurses should be aware that proper dosing requires an initial loading dose of 2,000 mg followed by a maintenance dose of 800 mg given every two weeks. Ten vials are needed to make up the loading dose and four vials the maintenance dose. Further dilution in 250 mL of normal saline is required. The reconstituted drug should be administered immediately; it can also be refrigerated for up to 24 hours. If refrigerated, it must be at room temperature for at least 30 minutes, but not for more than four hours, before administration. IV infusion into the cephalic vein of either arm is recommended. The drug should never be given as an IV push or bolus. Because of the risk of infusion-associated adverse effects, the loading dose should be administered over a minimum of 30 minutes. If no infusion reaction is noted, the maintenance doses can be infused over at least 15 minutes.
Nurses should observe the patient for adverse reactions for at least an hour after the loading dose. If the patient tolerates the loading dose, the observation time for maintenance doses can be 15 minutes. Patient education on the need to receive ibalizumab-uiyk every two weeks to maintain its therapeutic effect and avoid potential resistance is important. Nurses should also teach patients not to independently stop any of their other anti-HIV medications. For complete prescribing information for ibalizumab-uiyk, see http://www.accessdata.fda.gov/drugsatfda_docs/label/2018/761065lbl.pdf.