Emicizumab

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 (congenital factor VIII deficiency) with or without factor VIII inhibitors. HEMLIBRA 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 ages newborn and older with hemophilia A (congenital factor VIII deficiency) with or without factor VIII inhibitors. ( 1 )

HEMLIBRA is available as a colorless to slightly yellow solution in single-dose vials. Injection: 12 mg/0.4 mL 30 mg/mL 60 mg/0.4 mL 105 mg/0.7 mL 150 mg/mL 300 mg/2 mL (150 mg/mL) Injection: 12 mg/0.4 mL in a single-dose vial ( 3 ) 30 mg/mL in a single-dose vial ( 3 ) 60 mg/0.4 mL in a single-dose vial ( 3 ) 105 mg/0.7 mL in a single-dose vial ( 3 ) 150 mg/mL in a single-dose vial ( 3 ) 300 mg/2 mL (150 mg/mL) in a single-dose vial ( 3 )

None. None ( 4 )

Immunogenicity: Anti-emicizumab antibodies (including neutralizing antibodies) have developed in HEMLIBRA-treated patients. In case of clinical signs of loss of efficacy, promptly assess the etiology and consider a change in treatment if neutralizing antibodies are suspected. ( 5.3 , 12.6 , 14.3 ) Laboratory Coagulation Test Interference: HEMLIBRA interferes with activated clotting time (ACT), activated partial thromboplastin time (aPTT), and coagulation laboratory tests based on aPTT, including one-stage aPTT-based single-factor assays, aPTT-based Activated Protein C Resistance (APC-R), and Bethesda assays (clotting-based) for factor VIII (FVIII) inhibitor titers. Intrinsic pathway clotting-based laboratory tests should not be used. ( 5.4 , 7.2 )

5.1 Thrombotic Microangiopathy Associated with HEMLIBRA and aPCC Cases of thrombotic microangiopathy (TMA) were reported from clinical trials 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. In clinical trials, thrombotic microangiopathy was reported in 0.8% of patients (3/391) and in 8.1% of patients (3/37) who received at least one dose of aPCC. Patients presented with thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury, without severe deficiencies in ADAMTS13 activity. Evidence of improvement was seen within one week following discontinuation of aPCC. One patient resumed HEMLIBRA following resolution of TMA. Consider the benefits and risks if aPCC must be used in a patient receiving HEMLIBRA prophylaxis. Due to the long half-life of HEMLIBRA, the potential for an interaction with aPCC may persist for up to 6 months after the last dose. Monitor for the development of TMA when administering aPCC. Immediately discontinue aPCC and interrupt HEMLIBRA prophylaxis if clinical symptoms and/or laboratory findings consistent with TMA occur, and manage as clinically indicated. Consider the benefits and risks of resuming HEMLIBRA prophylaxis following complete resolution of TMA on a case-by-case basis.

5.2 Thromboembolism Associated with HEMLIBRA and aPCC Thrombotic events were reported from clinical trials when on average a cumulative amount of >100 U/kg/24 hours of aPCC was administered for 24 hours or more to patients receiving HEMLIBRA prophylaxis. In clinical trials, thrombotic events were reported in 0.5% of patients (2/391) and in 5.4% of patients (2/37) who received at least one dose of aPCC. No thrombotic event required anticoagulation therapy. Evidence of improvement or resolution was seen within one month following discontinuation of aPCC. One patient resumed HEMLIBRA following resolution of thrombotic event. Consider the benefits and risks if aPCC must be used in a patient receiving HEMLIBRA prophylaxis. Due to the long half-life of HEMLIBRA, the potential for an interaction with aPCC may persist for up to 6 months after the last dose. Monitor for the development of thromboembolism when administering aPCC. Immediately discontinue aPCC and interrupt HEMLIBRA prophylaxis if clinical symptoms, imaging, or laboratory findings consistent with thromboembolism occur, and manage as clinically indicated. Consider the benefits and risks of resuming HEMLIBRA prophylaxis following complete resolution of thrombotic events on a case-by-case basis.

5.3 Immunogenicity Treatment with HEMLIBRA may induce anti-drug antibodies. Anti-emicizumab-kxwh antibodies were reported in 5.1% of patients (34/668) treated with HEMLIBRA in clinical trials. Most patients with anti-emicizumab-kxwh antibodies did not experience a change in HEMLIBRA plasma concentrations or an increase in bleeding events; however, in uncommon cases (incidence < 1%), the presence of neutralizing antibodies with decreasing plasma concentration may be associated with loss of efficacy [see Clinical Pharmacology (12.6) , Clinical Studies (14.3) ] . Monitor for clinical signs of loss of efficacy (e.g., increase in breakthrough bleeding events) and if observed, promptly assess the etiology and consider a change in treatment if neutralizing anti-emicizumab-kxwh antibodies are suspected.

5.4 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 ( Table 1 ). Therefore, intrinsic pathway clotting-based laboratory test results in patients treated with HEMLIBRA should not be used to monitor HEMLIBRA activity, determine dosing for factor replacement or anti-coagulation, or measure FVIII inhibitor titers [see Drug Interactions (7.2) ]. Laboratory tests affected and unaffected by HEMLIBRA are shown in Table 1 . Table 1 Coagulation Test Results Affected and Unaffected by HEMLIBRA Results Affected by HEMLIBRA Results Unaffected by HEMLIBRA Activated partial thromboplastin time (aPTT) Bethesda assays (clotting-based) for FVIII inhibitor titers One-stage, aPTT-based, single-factor assays aPTT-based Activated Protein C Resistance (APC-R) Activated clotting time (ACT) 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 For important considerations regarding FVIII chromogenic activity assays, see Drug Interactions (7.2) . Immuno-based assays (i.e., ELISA, turbidimetric methods) Genetic tests of coagulation factors (e.g., Factor V Leiden, Prothrombin 20210)

The following serious adverse reactions are described elsewhere in the labeling: Thrombotic Microangiopathy Associated with HEMLIBRA and aPCC [see Warnings and Precautions (5.1) ] Thromboembolism Associated with HEMLIBRA and aPCC [see Warnings and Precautions (5.2) ] Most common adverse reactions (incidence ≥ 10%) are injection site reactions, headache, and arthralgia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Genentech at 1-888-835-2555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 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. 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 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 urticaria, and injection site warmth. 85 (22%) Pyrexia 23 (6%) Nervous System Disorders Headache 57 (15%) Gastrointestinal Disorders Diarrhea 22 (6%) Musculoskeletal and Connective Tissue Disorders Arthralgia 59 (15%) 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 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. 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 3 Thrombotic event. > 48 hours 1 5 10 , 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 Rhabdomyolysis was reported in two adult patients with asymptomatic elevations in serum creatine kinase without associated renal or musculoskeletal symptoms. In both instances, the event occurred following an increase in physical activity.

6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of HEMLIBRA. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Skin and subcutaneous tissue disorders : rash, urticaria, angioedema. Immune system disorders : hypersensitivity.

7.1 Hypercoagulability with Concomitant Use of aPCC Clinical experience suggests that a drug interaction exists with HEMLIBRA and aPCC [see Warnings and Precautions (5.1 , 5.2) ] .

7.2 Drug-Laboratory Test Interactions HEMLIBRA restores the tenase cofactor activity of missing activated factor VIII (FVIIIa). Coagulation laboratory tests based on intrinsic clotting (i.e., aPTT) measure the total clotting time including time needed for activation of FVIII to FVIIIa by thrombin. Such intrinsic pathway-based tests will yield overly shortened clotting times with HEMLIBRA, which does not require activation by thrombin. The overly shortened intrinsic clotting time will then disturb all single-factor assays based on aPTT, such as the one-stage FVIII activity assay; however, single-factor assays utilizing chromogenic or immuno-based methods are unaffected by HEMLIBRA and may be used to monitor coagulation parameters during treatment, with specific considerations for FVIII chromogenic activity assays as described below. Chromogenic FVIII activity tests may be manufactured with either human or bovine coagulation proteins. Assays containing human coagulation factors are responsive to HEMLIBRA but may overestimate the clinical hemostatic potential of HEMLIBRA. In contrast, assays containing bovine coagulation factors are insensitive to HEMLIBRA (no activity measured) and can be used to monitor endogenous or infused FVIII activity, or to measure anti-FVIII inhibitors. HEMLIBRA remains active in the presence of inhibitors against FVIII, so it will produce a false-negative result in clotting-based Bethesda assays for functional inhibition of FVIII. Instead, a chromogenic Bethesda assay utilizing a bovine-based FVIII chromogenic test that is insensitive to HEMLIBRA may be used. Due to the long half-life of HEMLIBRA, effects on coagulation assays may persist for up to 6 months after the last dose [see Clinical Pharmacology (12.3) ] .

8.1 Pregnancy Risk Summary There are no available data on HEMLIBRA use in pregnant women to inform a drug-associated risk of major birth defects and miscarriage. Animal reproduction studies have not been conducted with emicizumab-kxwh. 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. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. In the U.S. general population, the estimated background risk of major birth defect and miscarriage in clinically recognized pregnancies is 2 – 4% and 15 – 20%, respectively.

8.2 Lactation Risk Summary There is no information regarding the presence of emicizumab-kxwh in human milk, the effects on the breastfed child, or the effects on milk production. Human IgG is known to be present in human milk. 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.

8.3 Females and Males of Reproductive Potential Contraception Women of childbearing potential should use contraception while receiving HEMLIBRA.

8.4 Pediatric Use The safety and efficacy of HEMLIBRA have been established in pediatric patients. Use of HEMLIBRA in pediatric patients with hemophilia A is supported by two randomized trials (HAVEN 1 and HAVEN 3) and two single-arm trials (HAVEN 2 and HAVEN 4). All clinical trials included pediatric patients in the following age group: 47 adolescents (12 years up to less than 18 years). Only HAVEN 2 included pediatric patients in the following age groups: 55 children (2 years up to less than 12 years) and five infants (1 month up to less than 2 years). No differences in efficacy were observed between the different age groups [see Clinical Studies (14) ] . The steady-state plasma trough concentrations of emicizumab-kxwh were comparable in adult and pediatric patients older than 6 months at equivalent weight-based doses. Lower concentrations of emicizumab-kxwh were predicted in pediatric patients less than 6 months old [see Clinical Pharmacology (12.3) ] . In general, the adverse reactions in HEMLIBRA-treated pediatric patients were similar in type to those seen in adult patients with hemophilia A [see Adverse Reactions (6.1) ] .

8.5 Geriatric Use Clinical studies of HEMLIBRA did not include a sufficient number of patients aged 65 and over to determine whether they respond differently from younger patients. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

HEMLIBRA bridges activated factor IX and factor X to restore the function of missing activated factor VIII that is needed for effective hemostasis.