Our Commitment to Providing Balanced Scientific and Clinical Information About Emicizumab-kxwh

This website is intended to make available balanced, peer-reviewed, and scientifically rigorous clinical information about emicizumab-kxwh to enable healthcare professionals to make informed patient treatment decisions.

Our Commitment to Providing Balanced Scientific and Clinical Information About Emicizumab-kxwh

This website is intended to make available balanced, peer-reviewed, and scientifically rigorous clinical information about emicizumab-kxwh to enable healthcare professionals to make informed patient treatment decisions.

The Prescribing Information is the primary source of FDA-approved information about emicizumab and its use for the treatment of patients with congenital hemophilia A, with or without factor VIII inhibitors. The information on this website is provided to healthcare professionals for educational and informational purposes only.

The following emicizumab medical resources are available. Click below to learn more.

An update from Genentech on Hemlibra® post-approval data communication process and site update     

To the hemophilia community,

At Genentech, we recognize and appreciate the ongoing conversation within the hemophilia community around the long-term efficacy and safety of Hemlibra® (emicizumab-kxwh). We understand that the subject of long-term safety for hemophilia treatments is an important topic for this community and we remain committed to listening to you and providing information that leads to informed clinical decision making and patient care.

Genentech’s first U.S. medical websites for Hemlibra were originally launched in 2018 to provide updated, verified safety information to the hemophilia community, specifically related to adverse events (AEs) of interest, whether or not such events were related to Hemlibra. Today, Hemlibra is approved and available for people with hemophilia A in more than 90 countries and more than 7,200 patients around the world have been treated with Hemlibra. We now have much broader availability of information from databases and individual experiences, and the source of safety information has expanded from controlled clinical trial reporting to ongoing voluntary adverse event reporting by healthcare professionals, patients and their caregivers. That’s why we’ve launched updated versions of our medical websites and we’ve evolved our process for reporting post-approval information on Hemlibra to ensure transparency and meet the community’s expectations for information.

The updated U.S. Hemlibra medical sites – www.emipatientinfo.com for patients and www.emicizumabinfo.com for physicians – now provide broader clinical information on the efficacy and safety of Hemlibra. On these sites, we will report data from ongoing studies and real-world use of Hemlibra that are presented at scientific meetings and published in medical journals, as these data are available. Importantly, any future updates on Hemlibra will be appropriately benchmarked, peer reviewed and medically relevant.

We made this decision after actively engaging and working closely with the hemophilia medical and patient communities to understand what would be most impactful. This means that, together with members of the scientific community, we can provide a broader body of data in place of the quarterly data updates previously reported. In addition, Hemlibra’s label, as approved by the U.S. Food and Drug Administration (FDA), should always be the primary source of information on the safety and efficacy of the medicine.

Our commitment to providing timely and transparent updates on Hemlibra to the hemophilia community remains unchanged. We will continue to listen, respond and partner with you, so that together we can lead this collective effort for a continued dialogue allowing us to protect patient safety and put this community first.

Contact Information

Report Adverse Events (AEs) 
(888) 835-2555
Submit a Form
24 hrs/day, 7 days/week
Medical Questions about Emicizumab
(800) 821-8590
Monday - Friday, 5am - 5pm PT
Connect Virtually with a Medical Science Liaison
Submit a Form
Report Product Complaint
(800) 334-0290
Monday - Friday, 5am - 5pm PT


HEMLIBRA is indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients ages newborn and older with hemophilia A with or without factor VIII inhibitors.

Important Safety Information


Cases of thrombotic microangiopathy and thrombotic events were reported when on average a cumulative amount of >100 U/kg/24 hours of activated prothrombin complex concentrate (aPCC) was administered for 24 hours or more to patients receiving HEMLIBRA prophylaxis. Monitor for the development of thrombotic microangiopathy and thrombotic events if aPCC is administered. Discontinue aPCC and suspend dosing of HEMLIBRA if symptoms occur. 

Warnings and Precautions

Thrombotic Microangiopathy (TMA) and Thromboembolism Associated With HEMLIBRA and aPCC

In clinical trials, TMA was reported in 0.8% of patients (3/391) and thrombotic events were reported in 0.5% of patients (2/391). In patients who received at least one dose of aPCC, TMA was reported in 8.1% of patients (3/37) and thrombotic events were reported in 5.4% of patients (2/37). Patients with TMA presented with thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury, without severe deficiencies in ADAMTS13.

Consider the benefits and risks if aPCC must be used in a patient receiving HEMLIBRA prophylaxis. Monitor for the development of TMA and/or thromboembolism when administering aPCC. Immediately discontinue aPCC and interrupt HEMLIBRA prophylaxis if clinical symptoms, imaging, or laboratory findings consistent with TMA and/or thromboembolism occur, and manage as clinically indicated. Consider the benefits and risks of resuming HEMLIBRA prophylaxis following complete resolution of TMA and/or thrombotic events on a case-by-case basis.                             

Laboratory Coagulation Test Interference

HEMLIBRA affects intrinsic pathway clotting-based laboratory tests, including activated clotting time (ACT); activated partial thromboplastin time (aPTT); and all assays based on aPTT, such as one-stage, factor VIII (FVIII) activity. Therefore, intrinsic pathway clotting-based coagulation laboratory test results in patients who have been treated with HEMLIBRA prophylaxis should not be used to monitor HEMLIBRA activity, determine dosing for factor replacement or anti-coagulation, or measure FVIII inhibitor titers.

Results affected by HEMLIBRA: aPTT; Bethesda assays (clotting-based) for FVIII inhibitor titers; one-stage, aPTT-based single-factor assays; aPTT-based Activated Protein C Resistance (APC-R); ACT.

Results unaffected by HEMLIBRA: Bethesda assays (bovine chromogenic) for FVIII inhibitor titers; thrombin time (TT); one-stage, prothrombin time (PT)-based single-factor assays; chromogenic-based single-factor assays other than FVIII (see Drug Interactions for FVIII chromogenic activity assay considerations); immuno-based assays (ie, ELISA, turbidimetric methods); genetic tests of coagulation factors (eg, Factor V Leiden, Prothrombin 20210).            

Most Common Adverse Reactions

The most common adverse reactions (incidence ≥10%) are injection site reactions, headache, and arthralgia.

Adverse Reactions

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; 2 of the 13 were associated with thrombotic events and 3 of the 13 were associated with TMA. No TMA or thrombotic events were associated with the remaining instances of aPCC treatment.

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 pruritus (4%), and injection site pain (4%).

Other Less Common (<1%) Reactions

Rhabdomyolysis was reported in 2 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.

Drug Interactions

Clinical experience suggests that a drug interaction exists with HEMLIBRA and aPCC.

Pregnancy, Lactation, Females and Males of Reproductive Potential

Women of childbearing potential should use contraception while receiving HEMLIBRA. It is not known whether HEMLIBRA can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. HEMLIBRA should be used during pregnancy only if the potential benefit for the mother outweighs the risk to the fetus. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for HEMLIBRA and any potential adverse effects on the breastfed child from HEMLIBRA or from the underlying maternal condition.                           

You may report side effects to the FDA at (800) FDA-1088 or www.fda.gov/medwatch. You may also report side effects to Genentech at (888) 835-2555.