Medical Editor: John P. Cunha, DO, FACOEP Last updated on RxList: 9/16/2021
Hemlibra Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Hemlibra?

Hemlibra (emicizumab-kxwh) injection is a bispecific factor IXa- and factor X-directed antibody indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients with hemophilia A (congenital factor VIII deficiency) with factor VIII inhibitors.

What Are Side Effects of Hemlibra?

Common side effects of Hemlibra include:

Dosage for Hemlibra

The recommended dose of Hemlibra is 3 mg/kg by subcutaneous injection once weekly for the first 4 weeks, followed by 1.5 mg/kg once weekly.

What Drugs, Substances, or Supplements Interact with Hemlibra?

Hemlibra may interact with aPCC, rFVIIa, or FVIII. Tell your doctor all medications and supplements you use.

Hemlibra During Pregnancy or Breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant before using Hemlibra; it is unknown how it would affect a fetus. It is unknown if Hemlibra passes into breast milk. Human IgG is known to be present in breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Hemlibra (emicizumab-kxwh) Injection, for Subcutaneous Use Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


What is hemophilia? See Answer
Hemlibra Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

If you also use a bypassing agent, call your doctor right away if you have any of these side effects:

  • headache, weakness, confusion;
  • feeling light-headed or unusually sick;
  • back pain, little or no urination;
  • stomach pain, vomiting;
  • chest pain, feeling short of breath, coughing up blood;
  • swelling or redness in your arms or legs;
  • eye pain or swelling, vision problems;
  • numbness in your face; or
  • yellowing of your skin or eyes.

Common side effects may include:

  • headache;
  • joint pain; or
  • pain, swelling, burning, or irritation where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Hemlibra (Emicizumab-Kxwh Injection, for Subcutaneous Use)


Anemia Symptoms and Signs, Types, Treatment and Causes See Slideshow
Hemlibra Professional Information


The following serious adverse reactions are described elsewhere in the labeling:

  • Thrombotic Microangiopathy Associated with HEMLIBRA and aPCC [see WARNINGS AND PRECAUTIONS]
  • Thromboembolism Associated with HEMLIBRA and aPCC [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The following adverse reactions are based on pooled data from two randomized trials in adult and adolescent patients (HAVEN 1 and HAVEN 3), one single-arm trial in adult and adolescent patients (HAVEN 4), one single-arm trial in pediatric patients (HAVEN 2), and one dose-finding trial, in which a total of 391 male patients with hemophilia A received at least one dose of HEMLIBRA as routine prophylaxis. Two hundred eighty-one patients (72%) were adults (18 years and older), 50 (13%) were adolescents (12 years up to less than 18 years), 55 (14%) were children (2 years up to less than 12 years), and five (1%) were infants (1 month up to less than 2 years). The median duration of exposure across the studies was 34.1 weeks (0.1 to 224.4 weeks).

The most frequently reported adverse reactions observed in ≥ 10% of patients treated with HEMLIBRA were injection site reactions, headache, and arthralgia.

Four patients (1%) in the clinical trials receiving HEMLIBRA prophylaxis withdrew from treatment due to adverse reactions, which were thrombotic microangiopathy, skin necrosis and superficial thrombophlebitis, headache, and injection site reaction.

One patient withdrew from treatment after developing an anti-emicizumab-kxwh neutralizing antibody associated with loss of efficacy [see ADVERSE REACTIONS].

Adverse reactions observed in patients who received HEMLIBRA are shown in Table 2.

Table 2 : Adverse Reactions Reported in ≥ 5% of Patients from Pooled Clinical Trials with HEMLIBRA

Body System Adverse Reaction Number of Patients n (%)
(N = 391)
General Disorders and Administration Site Conditions Injection site reaction* 85 (22%)
Pyrexia 23 (6%)
Nervous System Disorders Headache 57 (15%)
Gastrointestinal Disorders Diarrhea 22 (6%)
Musculoskeletal and Connective Tissue Disorders Arthralgia 59 (15%)
* Includes injection site bruising, injection site discomfort, injection site erythema, injection site hematoma, injection site induration, injection site pain, injection site pruritus, injection site rash, injection site reaction, injection site swelling, injection site urticarial, and injection site warmth.

Characterization Of aPCC Treatment In Pooled Clinical Trials

There were 130 instances of aPCC treatment in 37 patients, of which 13 instances (10%) consisted of on average a cumulative amount of >100 U/kg/24 hours of aPCC for 24 hours or more; two of the 13 were associated with thrombotic events and three of the 13 were associated with TMA (Table 3). No TMA or thrombotic events were associated with the remaining instances of aPCC treatment.

Table 3 : Characterization of aPCC Treatment* in Pooled Clinical Trials

Duration of aPCC treatment Average cumulative amount of aPCC over 24 hours (U/kg/24 hours)
< 50 50-100 >100
< 24 hours 11 76 18
24 - 48 hours 0 6 3a
> 48 hours 1 5 10a,b,b,b
* An instance of aPCC treatment is defined as all doses of aPCC received by a patient, for any reason, until there was a 36-hour treatment-free break.
a Thrombotic event.
b Thrombotic microangiopathy.

Injection Site Reactions

In total, 85 patients (22%) reported injection site reactions (ISRs). All ISRs observed in HEMLIBRA clinical trials were reported as mild to moderate intensity and 93% resolved without treatment. The commonly reported ISR symptoms were injection site erythema (11%), injection site pain (4%), and injection site pruritus (4%).

Other Less Common (<1%) Reactions


Rhabdomyolysis was reported in two adult patients with asymptomatic elevations in serum creatinine kinase without associated renal or musculoskeletal symptoms. In both instances, the event occurred following an increase in physical activity.


As with all therapeutic proteins, there is a potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medication, and underlying disease. For these reasons, comparison of the incidence of antibodies to emicizumab-kxwh in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.

The immunogenicity of HEMLIBRA was evaluated using an enzyme-linked immunosorbent assay (ELISA) or an electrochemiluminescence (ECL) assay. In the dose-finding trial (n = 18), four patients tested positive for anti-emicizumab-kxwh antibodies. In the pooled HAVEN clinical trials, 3.5% of patients (14/398) tested positive for anti-emicizumab-kxwh antibodies and <1% of patients (3/398) developed anti-emicizumab-kxwh antibodies with neutralizing potential (based on declining pharmacokinetics). One patient from HAVEN 2, who developed an antiemicizumab- kxwh neutralizing antibody, experienced loss of efficacy after 5 weeks of treatment.

There was no clinically apparent impact of the presence of anti-emicizumab-kxwh antibodies on safety.

Read the entire FDA prescribing information for Hemlibra (Emicizumab-Kxwh Injection, for Subcutaneous Use)

© Hemlibra Patient Information is supplied by Cerner Multum, Inc. and Hemlibra Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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