ibalizumab (Rx)

1-10%

Diarrhea (8%)

Dizziness (8%)

Nausea (5%)

Rash (5%)

Laboratory abnormalities ≥grade 3

• Creatinine >1.8x ULN or 1.5x baseline (10%)
• Bilirubin ≥2.6x ULN (5%)
• Lipase >3x ULN (5%)
• Leukocytes <1.5 x 10^9 cells/L (5%)
• Neutrophils <0.6 x 10^9 cell/L (5%)
• Direct bilirubin >ULN (3%)
• Blood glucose >250 mg/dL (3%)
• Uric acid >3x ULN (3%)
• Hemoglobin <8.5 g/dL (3%)
• Platelets <50,000/mm³ (3%)
• Leukocytes <1.5 x 10^9 cells/L (5%)

Contraindications

None

Cautions

Immune reconstitution inflammatory syndrome reported in 1 patient treated with ibalizumab in combination with other ARTs

During the initial phase of combination ARTs, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections, which may necessitate further evaluation and treatment

Pregnancy

No data are available to determine risk during pregnancy

Monoclonal antibodies are transported across the placenta as pregnancy progresses; therefore, ibalizumab has the potential to be transmitted from the mother to the developing fetus

Healthcare providers are encouraged to enroll patients in the Antiretroviral Pregnancy Registry at www.apregistry.com or call 800-258-4263 (Canada and US)

Lactation

Unknown if distributed into breast milk

The Centers for Disease Control and Prevention recommend that HIV-1-infected mothers in United States not breastfeed infants to avoid risking postnatal transmission of HIV-1 infection

Owing to the potential for HIV transmission (in HIV-negative infants), developing viral resistance (in HIV-positive infants), and adverse reactions in a breastfed infant, instruct mothers not to breastfeed

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

CD4-directed post-attachment HIV-1 inhibitor

Recombinant humanized monoclonal antibody; blocks HIV-1 from infecting CD4+ T cells by binding to domain 2 of CD4 and interfering with post-attachment steps required for the entry of HIV-1 virus particles into host cells and preventing the viral transmission that occurs via cell-cell fusion

Binding specificity of ibalizumab to domain 2 of CD4 allows ibalizumab to block viral entry into host cells without causing immunosuppression

Absorption

Single-dose administrations of ibalizumab

• AUC-time curve increased in a greater than dose-proportional manner

Single loading dose followed by a maintenance dose q2wk

• Steady-state concentrations were reached after the first 800-mg maintenance dose with mean concentrations >30 mcg/mL throughout the dosing interval

Distribution

Vd was approximately that of serum volume, at 4.8 L

Excretion

Clearance decreased from 9.54 to 0.36 mL/h/kg

Elimination half-life increased from 2.7 to 64 hr as the dose increased from 0.3 to 25 mg/kg

IV Compatibilities

0.9% NaCl

IV Preparation

Inspect solution; should appear colorless to slightly yellow and clear to slightly opalescent with no visible particles

Discard vial if solution is cloudy, there is pronounced discoloration, or foreign particulate matter is present

Select appropriate number of vials (200 mg/1.33 mL) required to prepare loading dose (2000 mg) or maintenance doses (800 mg)

Remove the flip-off cap from the single-dose vial and wipe with an alcohol swab

Insert sterile syringe needle into the vial through the center of the stopper and withdraw 1.33 mL from each vial (a small residual amount may remain in the vial)

Discard unused portion and transfer into a 250-mL IV bag of 0.9% NaCl; other IV solutions must not be used to prepare dose

Once diluted, solution should be administered immediately (also see Storage)

IV Administration

Do not administer as IV push or bolus

Diluted solution should be administered by a trained medical professional

Administer as an IV infusion in the cephalic vein in right or left arm; if this vein is not accessible, an appropriate vein located elsewhere can be used

Duration of the first infusion (loading dose) should be no less than 30 minutes; if no infusion-associated adverse reactions occur, the duration of the subsequent infusions (maintenance doses) can be decreased to no less than 15 minutes

After the infusion is complete, flush IV line with 30 mL of 0.9% NaCl

All patients must be observed for 1 hr after completing infusion for at least the first infusion; if the patient does not experience an infusion-associated adverse reaction, the postinfusion observation time can be reduced to 15 minutes thereafter

Missed maintenance dose

• If a maintenance dose (800 mg) is missed by ≥3 days beyond the scheduled dosing day, administer a loading dose (2000 mg) as early as possible
• Resume maintenance dosing (800 mg) every 14 days thereafter

Storage

Unopened vials

• Refrigerate at 2-8°C (36-46°F)
• Do not freeze
• Protect from light

Diluted solution

• If not administered immediately, store at room temperature (20-25°C [68-77°F]) for up to 4 hr OR
• Refrigerate at 2-8°C (36-46°F) for up to 24 hr
• If refrigerated, allow the diluted solution to stand at room temperature (20-25°C [68-77°F]) for at least 30 minutes but no more than 4 hr before administration