EMICIZUMAB Drug Interactions: What You Need to Know

INTERACTIONS

7.1 Hypercoagulability with Concomitant Use of aPCC Clinical experience suggests that a drug interaction exists with HEMLIBRA and aPCC <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1 , 5.2) ]</span> .

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 <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> .

None. None ( 4 )

AND PRECAUTIONS 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 &gt;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 &gt;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 &lt; 1%), the presence of neutralizing antibodies with decreasing plasma concentration may be associated with loss of efficacy <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.6) , Clinical Studies (14.3) ]</span> . 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 <span class="opacity-50 text-xs">[see Drug Interactions (7.2) ]</span>. 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)