LEQEMBI

Lecanemab-irmb is a recombinant humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against aggregated soluble and insoluble forms of amyloid beta, and is expressed in a Chinese hamster ovary cell line. Lecanemab-irmb has an approximate molecular weight of 150 kDa. LEQEMBI Injection for Intravenous Use LEQEMBI (lecanemab-irmb) injection is a sterile, preservative-free, clear to opalescent and colorless to pale yellow solution for intravenous infusion after dilution. LEQEMBI is supplied in single-dose vials available in concentrations of 500 mg/5 mL (100 mg/mL) or 200 mg/2 mL (100 mg/mL). Each mL of solution contains 100 mg of lecanemab-irmb and arginine hydrochloride (42.13 mg), histidine (0.18 mg), histidine hydrochloride monohydrate (4.99 mg), polysorbate 80 (0.50 mg), and Water for Injection at an approximate pH of 5.0. LEQEMBI IQLIK Injection for Subcutaneous Use LEQEMBI IQLIK (lecanemab-irmb) injection is a sterile, preservative-free, clear to opalescent and colorless to pale yellow solution for subcutaneous use. LEQEMBI IQLIK is supplied in a single-dose prefilled autoinjector available in the concentration of 360 mg/1.8 mL with a 29-gauge fixed ½-inch needle. Each LEQEMBI IQLIK autoinjector contains 360 mg/1.8 mL lecanemab-irmb formulated in: arginine hydrochloride (75.83 mg), histidine (0.25 mg), histidine hydrochloride monohydrate (9.09 mg), polysorbate 80 (0.90 mg), and Water for Injection, USP.

LEQEMBI is indicated for the treatment of Alzheimer’s disease. Treatment with LEQEMBI should be initiated in patients with mild cognitive impairment or mild dementia stage of disease, the population in which treatment was initiated in clinical trials. LEQEMBI is an amyloid beta-directed antibody indicated for the treatment of Alzheimer’s disease. Treatment with LEQEMBI should be initiated in patients with mild cognitive impairment or mild dementia stage of disease, the population in which treatment was initiated in clinical trials. ( 1 )

Confirm the presence of amyloid beta pathology prior to initiating treatment. ( 2.1 ) Obtain a recent baseline brain MRI prior to initiating treatment. ( 2.4 , 5.1 ) Obtain an MRI within approximately one week prior to the 3 rd , 5 th , 7 th , and 14 th infusions. If radiographically observed ARIA occurs, treatment recommendations are based on type, severity, and presence of symptoms. ( 2.4 , 5.1 ) Recommended starting dosage: 10 mg/kg once every 2 weeks administered after dilution as an intravenous infusion over approximately one hour. ( 2.2 ) After 18 months, continue treatment once every 2 weeks or transition to an intravenous or subcutaneous maintenance dosage. ( 2.2 ) Recommended maintenance dosage: Intravenous infusion: 10 mg/kg once every 4 weeks ( 2.2 , 2.5 ) Subcutaneous injection: 360 mg administered once a week using the LEQEMBI IQLIK autoinjector ( 2.2 , 2.6 ). See Full Prescribing Information for preparation and administration instructions. ( 2.5 , 2.6 ) 2.1 Patient Selection Confirm the presence of amyloid beta pathology prior to initiating treatment [see Clinical Pharmacology ( 12.1 )] . 2.2 Recommended Dosage Initiate LEQEMBI as an intravenous infusion using the starting dosage (see Table 1). After 18 months, the starting dosage may be continued or a transition to maintenance dosage regimen may be considered, which can be administered by either intravenous infusion or subcutaneous injection (see Table 1). If transitioning from starting dosage to a maintenance dosage regimen, administer the first maintenance dose two weeks after the last starting dose. Table 1: Starting and Maintenance Dosage Regimens Route of Administration Dose Frequency Infusion Rate (if Intravenous) Starting Dosage Intravenous Only (LEQEMBI) 10 mg/kg Once every 2 weeks Over approximately one hour Maintenance Dosage Intravenous (LEQEMBI) 10 mg/kg Once every 4 weeks Over approximately one hour Subcutaneous (LEQEMBI IQLIK) 360 mg Once every week ------------------------ For intravenous infusion, use LEQEMBI vials. LEQEMBI vials must be diluted before administration [see Dosage and Administration ( 2.5 )]. For subcutaneous administration, use LEQEMBI IQLIK [see Dosage and Administration ( 2.6 )]. 2.3 Switching Between Maintenance Dosage Regimens During maintenance dosage regimen, patients may switch the route of administration (intravenous LEQEMBI or subcutaneous LEQEMBI IQLIK). This transition should be initiated at 1 week following the last maintenance dose of either the intravenous or subcutaneous dosing regimen. Thereafter, follow the dosing schedule for the newly assigned maintenance dosage regimen. 2.4 Monitoring and Dosing Interruption for Amyloid Related Imaging Abnormalities LEQEMBI can cause amyloid related imaging abnormalities -edema (ARIA-E) and -hemosiderin deposition (ARIA-H) [ see Warnings and Precautions ( 5.1 )] . Monitoring for ARIA Obtain a recent baseline brain magnetic resonance imaging (MRI) prior to initiating treatment with LEQEMBI. Obtain an MRI prior to the 3 rd , 5 th , 7 th , and 14 th infusions. In general, the MRI should be performed within approximately one week before the scheduled infusion of LEQEMBI and reviewed prior to proceeding with the infusion. If a patient experiences symptoms suggestive of ARIA, clinical evaluation should be performed, including an MRI if indicated. Recommendations for Dosing Interruptions in Patients with ARIA ARIA-E The recommendations for dosing interruptions for patients with ARIA-E are provided in Table 2. Table 2: Dosing Recommendations for Patients with ARIA-E Clinical Symptom Severity 1 ARIA-E Severity on MRI 2 Mild Moderate Severe Asymptomatic May continue dosing Suspend dosing 3 Suspend dosing 3 Mild May continue dosing based on clinical judgment Suspend dosing 3 Moderate or Severe Suspend dosing 3 1 Clinical Symptom Severity Categories: Mild: discomfort noticed, but no disruption of normal daily activity. Moderate: discomfort sufficient to reduce or affect normal daily activity. Severe: incapacitating, with inability to work or to perform normal daily activity. 2 See Table 4 for MRI radiographic severity [Warnings and Precautions ( 5.1 )] . 3 Suspend until MRI demonstrates radiographic resolution and symptoms, if present, resolve; consider a follow-up MRI to assess for resolution 2 to 4 months after initial identification. Resumption of dosing should be guided by clinical judgment. ARIA-H The recommendations for dosing interruptions for patients with ARIA-H are provided in Table 3. Table 3: Dosing Recommendations for Patients with ARIA-H Clinical Symptom Severity ARIA-H Severity on MRI 1 Mild Moderate Severe Asymptomatic May continue dosing Suspend dosing 2 Suspend dosing 3 Symptomatic Suspend dosing 2 Suspend dosing 2 1 See Table 4 for MRI radiographic severity [Warnings and Precautions ( 5.1 )] . 2 Suspend until MRI demonstrates radiographic stabilization and symptoms, if present, resolve; resumption of dosing should be guided by clinical judgment; consider a follow-up MRI to assess for stabilization 2 to 4 months after initial identification. 3 Suspend until MRI demonstrates radiographic stabilization and symptoms, if present, resolve; use clinical judgment in considering whether to continue treatment or permanently discontinue LEQEMBI. In patients who develop intracerebral hemorrhage greater than 1 cm in diameter during treatment with LEQEMBI, suspend dosing until MRI demonstrates radiographic stabilization and symptoms, if present, resolve. Use clinical judgment in considering whether to continue treatment after radiographic stabilization and resolution of symptoms or permanently discontinue LEQEMBI. 2.5 Preparation and Administration of LEQEMBI for Intravenous Infusion Dilution Prior to intravenous administration, LEQEMBI must be diluted in 250 mL of 0.9% Sodium Chloride Injection, USP. Use aseptic technique when preparing the LEQEMBI diluted solution for intravenous infusion. Calculate the dose (mg), the total volume (mL) of LEQEMBI solution required, and the number of vials needed based on the patient’s actual body weight and the recommended dose of 10 mg/kg. Each vial contains a LEQEMBI concentration of 100 mg/mL. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Check that the LEQEMBI solution is clear to opalescent and colorless to pale yellow. Do not use if opaque particles, discoloration, or other foreign particles are present. Remove the flip-off cap from the vial. Insert the sterile syringe needle into the vial through the center of the rubber stopper. Withdraw the required volume of LEQEMBI from the vial(s) and add to an infusion bag containing 250 mL of 0.9% Sodium Chloride Injection, USP. Each vial is for one-time use only. Discard any unused portion. Gently invert the infusion bag containing the LEQEMBI diluted solution to mix completely. Do not shake. After dilution, immediate use is recommended [see Description ( 11 )] . If not administered immediately, store LEQEMBI refrigerated at 2°C to 8°C (36°F to 46°F) for up to 4 hours, or at room temperature up to 30°C (86°F) for up to 4 hours. Do not freeze. Administration • Visually inspect the LEQEMBI diluted solution for particles or discoloration prior to administration. Do not use if it is discolored, opaque, or foreign particles are seen. • Prior to infusion, allow the LEQEMBI diluted solution to warm to room temperature. • Infuse the entire volume of the LEQEMBI diluted solution intravenously over approximately one hour through an intravenous line containing a terminal low-protein binding 0.2 micron in-line filter. Flush infusion line to ensure all LEQEMBI is administered. • Monitor for any signs or symptoms of an infusion-related reaction during the infusion and consider longer periods of observation if clinically indicated. The infusion rate may be reduced, or the infusion may be discontinued, and appropriate therapy administered as clinically indicated. Consider pre-medication at subsequent dosing with antihistamines, non-steroidal anti-inflammatory drugs, or corticosteroids [see Warnings and Precautions ( 5.3 )]. 2.6 Preparation and Administration of LEQEMBI IQLIK for Subcutaneous Injection Instruct patients and/or caregivers on the proper subcutaneous administration of LEQEMBI IQLIK. Direct patients and/or caregivers to follow the directions provided in the Instructions for Use for additional details on administration [see Instructions for Use ]. Periodically reassess the ability of the patient or caregiver to safely and adequately administer LEQEMBI IQLIK. • Before injection, remove LEQEMBI IQLIK from the refrigerator and leave at room temperature for 20 minutes. Do not use an external heat source to heat LEQEMBI IQLIK because heat may damage the product. • Do not shake LEQEMBI IQLIK. • Visually inspect LEQEMBI IQLIK for particles or discoloration prior to administration. The solution should be a clear to opalescent, colorless to pale yellow solution, and free of visible particles. Do not use LEQEMBI IQLIK if it is cloudy or there are visible particles. • Do not use LEQEMBI IQLIK if it looks damaged or has been dropped. • Sites for injection include the abdomen, upper thigh, and back of the upper arm. • Do not inject into moles, scars, bruises, tattoos or into areas where the skin is red, hard, tender or injured. • Monitor for signs or symptoms of an injection reaction. 2.7 Missed Dose Intravenous Infusion If a starting dosage or maintenance dosage infusion is missed, administer the next dose as soon as possible. Subcutaneous Injection If a scheduled dose of the subcutaneous maintenance dosing regimen is missed, administer LEQEMBI IQLIK as soon as possible up to 6 days after the missed dose and administer the next dose on the regularly scheduled day. Thereafter, resume the original dosing schedule.

LEQEMBI is contraindicated in patients with serious hypersensitivity to lecanemab-irmb or to any of the excipients of LEQEMBI or LEQEMBI IQLIK. Reactions have included angioedema and anaphylaxis [see Warnings and Precautions ( 5.2 )]. LEQEMBI is contraindicated in patients with serious hypersensitivity to lecanemab-irmb or to any of the excipients of LEQEMBI or LEQEMBI IQLIK. ( 4 )

The following clinically significant adverse reactions are described elsewhere in the labeling: Amyloid Related Imaging Abnormalities [see Warnings and Precautions ( 5.1 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.2 )] Infusion-Related Reactions [see Warnings and Precautions ( 5.3 )] Most common adverse reactions (at approximately 10% and higher incidence compared to placebo): infusion-related reactions, amyloid related imaging abnormality-microhemorrhages, amyloid related imaging abnormality-edema/effusion, and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Eisai Inc. at 1-888-274-2378 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. Clinical Trials with Intravenous Administration The safety of LEQEMBI has been evaluated in 2090 patients who received at least one dose of LEQEMBI by intravenous infusion. In Studies 1 and 2 in patients with Alzheimer’s disease, 1059 patients received LEQEMBI 10 mg/kg every two weeks by intravenous infusion [see Clinical Studies ( 14 )] . Of these 1059 patients, 50% were female, 79% were White, 15% were Asian, 12% were of Hispanic or Latino ethnicity, and 2% were Black. The mean age at study entry was 72 years (range from 50 to 90 years). In the combined double-blind, placebo-controlled period and long-term extension period of Studies 1 and 2, 1604 patients received LEQEMBI for at least 6 months, 1261 patients for at least 12 months, and 965 patients for 18 months. In the double-blind, placebo-controlled period in Study 1, patients stopped study treatment because of an adverse reaction in 15% of patients treated with LEQEMBI, compared to 6% patients on placebo; in Study 2, patients stopped study treatment because of an adverse reaction in 7% of patients treated with LEQEMBI, compared to 3% patients on placebo. In Study 1, the most common adverse reaction leading to discontinuation of LEQEMBI was infusion-related reactions that led to discontinuation in 2% (4/161) of patients treated with LEQEMBI, compared to 1% (2/245) of patients on placebo. In Study 2, the most common adverse reaction leading to discontinuation of LEQEMBI was ARIA-H microhemorrhages that led to discontinuation in 2% (15/898) of patients treated with LEQEMBI, compared to <1% (1/897) of patients on placebo. Table 5 shows adverse reactions that were reported in at least 5% of patients treated with LEQEMBI and at least 2% more frequently than in patients on placebo in Study 1. Table 5: Adverse Reactions Reported in at Least 5% of Patients Treated with LEQEMBI 10 mg/kg Every Two Weeks and at least 2% Higher than Placebo in Study 1 Adverse Reaction LEQEMBI 10 mg/kg Every Two Weeks N= 161 % Placebo N= 245 % Infusion-related reactions 20 3 Headache 14 10 ARIA-E 10 1 Cough 9 5 Diarrhea 8 5 Table 6 shows adverse reactions that were reported in at least 5% of patients treated with LEQEMBI and at least 2% more frequently than in patients on placebo in Study 2. Table 6: Adverse Reactions Reported in at Least 5% of Patients Treated with LEQEMBI 10 mg/kg Every Two Weeks and at least 2% Higher than Placebo in Study 2 Adverse Reaction LEQEMBI 10 mg/kg Every Two Weeks N= 898 % Placebo N= 897 % Infusion-related reactions 26 7 ARIA-H 14 8 ARIA-E 13 2 Headache 11 8 Superficial siderosis of central nervous system 6 3 Rash 1 6 4 Nausea/Vomiting 6 4 1 Rash includes acne, erythema, infusion site rash, injection site rash, rash, rash erythematous, rash pruritic, skin reactions, and urticaria. Less Common Adverse Reactions Atrial fibrillation occurred in 3% of patients treated with LEQEMBI, compared to 2% in patients on placebo. In Study 1, lymphopenia or decreased lymphocyte count was reported in 4% of patients treated with LEQEMBI after the first dose, compared to less than 1% of patients on placebo [see Warnings and Precautions ( 5.3 )]; lymphocytes were not measured after the first dose in Study 2. Clinical Trials with Subcutaneous Administration The safety of LEQEMBI IQLIK for maintenance treatment was evaluated in an open-label study, which included 49 patients who received LEQEMBI IQLIK 360 mg by subcutaneous administration once every week. The overall safety profile in these patients was similar to what was observed in patients who received LEQEMBI by intravenous infusion in Study 1 and Study 2. Patients who received LEQEMBI IQLIK experienced localized and systemic injection-related reactions. Localized injection-related reactions included erythema, induration, swelling, heat, pain, pruritis, rash, ecchymosis, and hematoma. Systemic injection-related reactions were observed less frequently, with symptoms of headache, fever, and fatigue. Injection-related reactions in patients receiving LEQEMBI IQLIK were mild or moderate in severity.

16.2 Storage and Handling Intravenous Infusion Unopened Vial Store LEQEMBI vials in a refrigerator at 2°C to 8°C (36°F to 46°F). Store in the original carton to protect from light. Do not freeze or shake. Diluted Solution For storage of the diluted infusion solution, see Dosage and Administration ( 2.5 ) . Subcutaneous Injection Store LEQEMBI IQLIK autoinjectors in a refrigerator at 2°C to 8°C (36°F to 46°F). Store in original carton to protect from light. Do not freeze. If needed, the autoinjector can be stored at room temperature up to 25°C (77°F) in the original carton for up to 14 days. Once the autoinjector has been stored at room temperature, do not return it to the refrigerator. Discard the autoinjector if these conditions are exceeded.