Ibalizumab Side Effects: What to Expect and When to Call Your Doctor

Overview: Is Ibalizumab Well Tolerated?

Ibalizumab (Trogarzo) is generally considered to have a favorable tolerability profile compared to many older HIV medications. In Phase 3 clinical trials, most participants tolerated the medication well. However, side effects do occur, and some are serious enough to require immediate medical attention.

Because ibalizumab is administered by IV infusion and patients are monitored for at least 1 hour after the first dose (and 15 minutes after subsequent doses), infusion reactions can often be identified and managed before patients leave the clinical setting.

Common Side Effects of Ibalizumab

The most commonly reported side effects in clinical trials include:

Diarrhea (reported in approximately 8% of patients)

Dizziness (approximately 8% of patients). Alcohol use may increase the risk of dizziness.

Nausea (approximately 5% of patients)

Rash (approximately 5% of patients)

Headache — also reported in clinical trial participants

Depression — reported less commonly but noted in study participants

These side effects are generally mild and do not typically require stopping treatment. Always report side effects to your healthcare provider so they can be properly evaluated and managed.

Serious Side Effects: When to Seek Immediate Help

Although uncommon, ibalizumab can cause serious side effects that require immediate medical attention:

1. Hypersensitivity Reactions (Including Anaphylaxis)

Ibalizumab can cause allergic reactions, including serious anaphylactic reactions. These can occur during or after the infusion. Symptoms include:

Trouble breathing or wheezing

Swelling of the face, lips, tongue, or throat

Hives or severe rash

Chest pain or chest tightness

Hot flush, nausea, or vomiting during infusion

If you experience any of these symptoms during or after your infusion, immediately alert the medical staff or call 911. Do not receive additional ibalizumab if you have had a clinically significant hypersensitivity reaction.

2. Immune Reconstitution Inflammatory Syndrome (IRIS)

When you start ibalizumab and your immune system begins recovering, it may react strongly to infections that were previously 'hidden' in your body. This is called Immune Reconstitution Inflammatory Syndrome (IRIS).

IRIS was reported in 1 patient in the Phase 3 clinical trial. Symptoms of IRIS depend on the underlying infection but may include fever, night sweats, swollen lymph nodes, or new pain. Tell your doctor immediately if you notice new or worsening infection symptoms after starting ibalizumab.

3. Embryo-Fetal Toxicity Risk

Based on animal studies, ibalizumab may cause reversible immunosuppression (CD4+ T cell and B cell lymphocytopenia) in infants born to mothers who received ibalizumab during pregnancy. IgG antibodies like ibalizumab cross the placenta, particularly near term. If you are pregnant or become pregnant while on ibalizumab, talk to your healthcare provider immediately about the risks and benefits.

Important Safety Notes

Breastfeeding: CDC recommends that people with HIV do not breastfeed to prevent HIV transmission to the baby. Additionally, ibalizumab's effects on breastfed infants are unknown.

Driving and coordination: Ibalizumab may cause dizziness that affects alertness and coordination. Avoid driving or operating machinery until you know how it affects you.

Resistance: Missing doses can allow viral rebound and the development of resistance to ibalizumab. Consistent biweekly infusion is essential.

For a complete list of drug interactions to be aware of, see our guide: Ibalizumab Drug Interactions: What to Avoid and What to Tell Your Doctor.

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