What Is Ibalizumab? Uses, Dosage, and What You Need to Know in 2026

What Is Ibalizumab?

Ibalizumab (brand name Trogarzo) is a humanized monoclonal antibody used to treat HIV-1 infection. It belongs to a class of antiretroviral drugs called entry inhibitors—specifically, it is a CD4-directed post-attachment HIV-1 inhibitor. It was approved by the FDA on March 6, 2018, and made history as:

The first monoclonal antibody approved to treat HIV

The first HIV therapy with a genuinely new mechanism of action in nearly 10 years at the time of approval

The recipient of FDA Breakthrough Therapy, Priority Review, Fast Track, and Orphan Drug designations

Ibalizumab is manufactured by Theratechnologies (distributed through TaiMed Biologics). It is sold only in the United States and must be administered by IV infusion or IV push every 14 days.

Who Is Ibalizumab For?

Ibalizumab is FDA-approved for a very specific patient population:

Adults only (not approved for children or adolescents)

HIV-1 infection (not HIV-2)

Heavily treatment-experienced (HTE): patients who have been through multiple antiretroviral regimens

Multidrug-resistant HIV-1 (MDR HIV-1): resistant to 3 or more classes of antiretroviral drugs

Currently failing their antiretroviral regimen (detectable viral load despite treatment)

Ibalizumab must always be used in combination with an optimized background regimen (OBR) of other antiretrovirals—it is never used alone.

What Dosage Form Does Ibalizumab Come In?

Ibalizumab comes as an injectable solution:

Single-dose glass vial: 200 mg per 1.33 mL (150 mg/mL)

Packaged in cartons of 2 vials

Storage: refrigerated 2–8°C; do not freeze; protect from light

How Is Ibalizumab Dosed?

There are two phases of ibalizumab dosing:

Loading dose: 2,000 mg given once as an IV infusion over 30 minutes or IV push over 90 seconds. Patients are observed for 1 hour after the first dose.

Maintenance dose: 800 mg every 14 days (every 2 weeks) as an IV infusion over 15 minutes or IV push over 30 seconds.

No dose adjustments are needed for ibalizumab regardless of the other antiretrovirals or medications the patient is taking.

What Happens If You Miss a Dose?

Missing a maintenance dose can have serious consequences. If you miss your scheduled dose by 3 or more days, you must restart with a 2,000 mg loading dose before continuing with maintenance. Call your HIV specialist and infusion provider immediately if you miss a dose or know you will be unable to attend your scheduled appointment.

How Effective Is Ibalizumab?

In the pivotal Phase 3 clinical trial (TMB-301), which included 40 heavily treatment-experienced patients with MDR HIV-1:

More than 80% of patients achieved at least a 70% reduction in viral load just 7 days after the 2,000 mg loading dose

43% of patients achieved full HIV-RNA suppression at 24 weeks

59% of patients achieved viral suppression at 48 weeks in longer-term follow-up data

Is Ibalizumab a Controlled Substance?

No. Ibalizumab is not a controlled substance and is not scheduled by the DEA. However, it is a specialty prescription drug that requires a prescription from a licensed healthcare provider and prior authorization from most insurance plans.

Want to understand exactly how ibalizumab works in the body? See our explainer: How Does Ibalizumab Work? Mechanism of Action Explained in Plain English.

Need help finding ibalizumab? medfinder calls providers near you to locate who can fill your prescription.