Margetuximab

MARGENZA is indicated, in combination with chemotherapy, for the treatment of adult patients with metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 regimens, at least one of which was for metastatic disease [see Dosage and Administration (2.1) and Clinical Studies (14.1) ]. MARGENZA is a HER2/neu receptor antagonist indicated, in combination with chemotherapy, for the treatment of adult patients with metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 regimens, at least one of which was for metastatic disease. ( 1 , 2.1 , 14.1 )

Injection: 250 mg/10 mL (25 mg/mL) clear to slightly opalescent, colorless to pale yellow or pale brown solution in a single-dose vial. Injection: 250 mg/10 mL (25 mg/mL) in a single-dose vial. ( 3 )

None. None. ( 4 )

Infusion-Related Reactions (IRRs): Monitor for signs and symptoms. If a significant infusion-associated reaction occurs, slow or interrupt the infusion and administer appropriate medical therapies. ( 5.3 )

5.1 Left Ventricular Dysfunction Left ventricular cardiac dysfunction can occur with MARGENZA. In SOPHIA, left ventricular dysfunction occurred in 1.9% of patients treated with MARGENZA. MARGENZA has not been studied in patients with a pretreatment LVEF value of < 50%, a prior history of myocardial infarction or unstable angina within 6 months, or congestive heart failure NYHA class II-IV. Withhold MARGENZA for ≥ 16% absolute decrease in LVEF from pretreatment values or LVEF value below institutional limits of normal (or 50% if no limits are available) and ≥ 10% absolute decrease in LVEF from pretreatment values. Permanently discontinue MARGENZA if LVEF decline persists for greater than 8 weeks, or if dosing is interrupted on greater than 3 occasions due to LVEF decline [see Dosage and Administration (2.2) ]. Cardiac Monitoring Conduct thorough cardiac assessment, including history, physical examination, and determination of LVEF by echocardiogram or MUGA scan. The following schedule is recommended: Baseline LVEF measurement within 4 weeks prior to initiation of MARGENZA LVEF measurements (MUGA/echocardiogram) every 3 months during and upon completion of MARGENZA Repeat LVEF measurement at 4-week intervals if MARGENZA is withheld for significant left ventricular cardiac dysfunction [see Dosage and Administration (2.2) ] .

5.2 Embryo-Fetal Toxicity Based on findings in animals and mechanism of action, MARGENZA can cause fetal harm when administered to a pregnant woman. There are no available data on the use of MARGENZA in pregnant women to inform the drug-associated risk. In postmarketing reports, use of a HER2-directed antibody during pregnancy resulted in cases of oligohydramnios and oligohydramnios sequence manifesting as pulmonary hypoplasia, skeletal abnormalities and neonatal death. In an animal reproduction study, intravenous administration of margetuximab-cmkb to pregnant cynomolgus monkeys once every 3 weeks starting at gestational day (GD) 20 until delivery resulted in oligohydramnios and delayed infant kidney development. Animal exposures were ≥ 3 times the human exposures at the recommended dose, based on C max . Verify pregnancy status of females of reproductive potential prior to initiation of MARGENZA. Advise pregnant women and females of reproductive potential that exposure to MARGENZA during pregnancy or within 4 months prior to conception can result in fetal harm. Advise females of reproductive potential to use effective contraception during treatment and for 4 months following the last dose of MARGENZA [see Use in Specific Populations (8.1 , 8.3) ].

5.3 Infusion-Related Reactions MARGENZA can cause infusion-related reactions (IRRs) [see Adverse Reactions (6.1) ]. Symptoms may include fever, chills, arthralgia, cough, dizziness, fatigue, nausea, vomiting, headache, diaphoresis, tachycardia, hypotension, pruritus, rash, urticaria, and dyspnea. In SOPHIA, IRRs were reported by 13% of patients on MARGENZA plus chemotherapy. Most of the IRRs occur during Cycle 1. Grade 3 IRRs were reported in 1.5% of MARGENZA-treated patients. All IRRs resolved within 24 hours, irrespective of severity. In SOPHIA, IRRs leading to interruption of treatment occurred in 9% of patients treated with MARGENZA and chemotherapy. One patient (0.4%) on MARGENZA discontinued treatment due to IRR. An infusion substudy in 88 patients in SOPHIA evaluated MARGENZA administered over 120 minutes for the initial dose, then 30 minutes from Cycle 2 forward. IRRs were ≤ Grade 2 and most occurred during the first (120 minutes) administration of MARGENZA. From Cycle 2 onward, one patient (1.1%) had an IRR (Grade 1). Monitor patients for IRRs during MARGENZA administration and as clinically indicated after completion of infusion. Have medications and emergency equipment to treat IRRs available for immediate use. Monitor patients carefully until resolution of signs and symptoms. In patients who experience mild or moderate IRRs, consider premedications, including antihistamines, corticosteroids, and antipyretics. Decrease the rate of infusion for mild or moderate IRRs. Interrupt MARGENZA infusion in patients experiencing dyspnea or clinically significant hypotension and intervene with medical therapy which may include epinephrine, corticosteroids, diphenhydramine, bronchodilators and oxygen. Patients should be evaluated and carefully monitored until complete resolution of signs and symptoms. Permanently discontinue MARGENZA in all patients with severe or life-threatening IRRs.

The following adverse reactions are discussed in greater detail in other sections of the label: Left Ventricular Dysfunction [see Warnings and Precautions (5.1) ] Embryo-Fetal Toxicity [see Warnings and Precautions (5.2) ] Infusion-Related Reactions [see Warnings and Precautions (5.3) ] The most common adverse drug reactions (>10%) with MARGENZA in combination with chemotherapy are fatigue/asthenia, nausea, diarrhea, vomiting, constipation, headache, pyrexia, alopecia, abdominal pain, peripheral neuropathy, arthralgia/myalgia, cough, decreased appetite, dyspnea, infusion-related reactions, palmar-plantar erythrodysesthesia, and extremity pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact TerSera Therapeutics LLC at 1-844-334-4035 or medicalinformation@tersera.com 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 rates observed in practice. The safety of MARGENZA was evaluated in HER2-positive breast cancer patients who received two or more prior anti-HER2 regimens in SOPHIA [see Clinical Studies (14.1) ]. Patients were randomized (1:1) to receive either MARGENZA 15 mg/kg every 3 weeks plus chemotherapy or trastuzumab plus chemotherapy. Among patients who received MARGENZA, 40% were exposed for 6 months or longer and 11% were exposed for greater than one year. Serious adverse reactions occurred in 16% of patients who received MARGENZA. Serious adverse reactions in > 1% of patients included febrile neutropenia (1.5%), neutropenia/neutrophil count decrease (1.5%) and infusion related reactions (1.1%). Fatal adverse reactions occurred in 1.1% of patients who received MARGENZA, including viral pneumonia (0.8%) and aspiration pneumonia (0.4%). Permanent discontinuation due to an adverse reaction occurred in 3% of patients who received MARGENZA. Adverse reactions which resulted in permanent discontinuation in > 1% of patients who received MARGENZA included left ventricular dysfunction and infusion-related reactions. Dosage interruptions due to an adverse reaction occurred in 11% of patients who received MARGENZA. Adverse reactions which required dosage interruption in > 5% of patients who received MARGENZA included infusion-related reactions. Table 1 summarizes the adverse reactions in SOPHIA. Table 1 Adverse Reactions (>10%) in Patients with Metastatic HER2-Positive Breast Cancer Who Received MARGENZA in SOPHIA Adverse Reaction MARGENZA + Chemotherapy (n = 264) Trastuzumab + Chemotherapy (n = 266) All Grades (%) Grade 3 or 4 (%) All Grades (%) Grade 3 or 4 (%) General disorders and administration site conditions Fatigue/Asthenia 57 7 47

4.5 Pyrexia 19 0.4 14

0.4 Gastrointestinal disorders Nausea 33 1.1 32

0.4 Diarrhea 25 2.3 25

2.3 Vomiting 21 0.8 14

1.5 Constipation 19 0.8 17

0.8 Abdominal pain Includes abdominal pain, abdominal discomfort, lower abdominal pain and upper abdominal pain 17 1.5 21

1.5 Skin and Subcutaneous tissue Alopecia 18 0 15 0 Palmar-plantar erythrodysesthesia 13 0 15 3 Nervous System Disorders Headache Includes headache and migraine 19 0 16 0 Peripheral neuropathy Includes peripheral neuropathy, peripheral sensory neuropathy, peripheral motor neuropathy, and neuropathy 16 1.1 15

2.3 Respiratory, thoracic and mediastinal disorders Cough 14 0.4 12 0 Dyspnea 13 1.1 11

2.3 Metabolism and nutrition disorders Decreased appetite 14 0.4 14

0.4 Musculoskeletal and connective tissue disorders Arthralgia/Myalgia 14 0.4 12

0.8 Extremity pain 11 0.8 9 0 Injury, poisoning and procedural complications Infusion-related reaction 13 1.5 3 0 Clinically relevant adverse reactions in ≤10% of patients who received MARGENZA in combination with chemotherapy included: dizziness and stomatitis (10%) each, decreased weight, dysgeusia, rash, and insomnia (6%) each, hypertension (5%), and syncope (1.5%). Table 2 summarizes the laboratory abnormalities in SOPHIA. Table 2 Select Laboratory Abnormalities (≥20%) That Worsened from Baseline in Patients with Metastatic HER2-Positive Breast Cancer Who Received MARGENZA in SOPHIA Laboratory Abnormality MARGENZA + Chemotherapy The denominator used to calculate the rate varied from 229 to 253 based on the number of patients with a baseline value and at least one post-treatment value. Trastuzumab + Chemotherapy All Grades (%) Grade 3 or 4 (%) All Grades (%) Grade 3 or 4 (%) aPTT: activated partial thromboplastin time; INR: prothrombin international normalized ratio; ALT: alanine aminotransferase; AST: aspartate aminotransferase Hematology Decreased hemoglobin 52 3.2 43

2.4 Decreased leukocytes 40 5 36

3.2 Decreased neutrophils 34 9 28 9 Increased aPTT 32 3.4 34

4.3 Decreased lymphocytes 31 4.4 38

4.4 Increased INR 24 1.2 25

0.4 Chemistry Increased creatinine 68 0.4 60 0 Increased ALT 32 2 30

0.8 Increased lipase 30 6 24

3.2 Increased AST 23 2 22

0.8 Increased alkaline phosphatase 21 0 23 0.8

Anthracyclines Patients who receive anthracyclines less than 4 months after stopping MARGENZA [see Clinical Pharmacology (12.3) ] may be at increased risk of cardiac dysfunction. While this interaction has not been studied with MARGENZA, clinical data from other HER2-directed antibodies warrants consideration. Avoid anthracycline-based therapy for up to 4 months after stopping MARGENZA. If concomitant use is unavoidable, closely monitor patient's cardiac function.

Females and Males of Reproductive Potential: Verify the pregnancy status of females prior to initiation of MARGENZA. ( 8.3 )

8.1 Pregnancy Risk Summary Based on findings in animals and mechanism of action, MARGENZA can cause fetal harm when administered to a pregnant woman. There are no available data on use of MARGENZA in pregnant women to inform the drug-associated risk. In postmarketing reports, use of a HER2-directed antibody during pregnancy resulted in cases of oligohydramnios and oligohydramnios sequence manifesting as pulmonary hypoplasia, skeletal abnormalities, and neonatal death. In an animal reproduction study, intravenous administration of margetuximab-cmkb to pregnant cynomolgus monkeys once every 3 weeks, starting at gestational day (GD) 20 until delivery, resulted in oligohydramnios and delayed infant kidney development. Animal exposures were ≥ 3 times the human exposures at the recommended dose, based on C max (see Data ) . Advise patients of potential risks to a fetus. There are clinical considerations if MARGENZA is used during pregnancy or within 4 months prior to conception (see Clinical Considerations ). Estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2 – 4% and 15 – 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Monitor women who received MARGENZA during pregnancy or within 4 months prior to conception for oligohydramnios. If oligohydramnios occurs, perform fetal testing that is appropriate for gestational age and consistent with community standards of care. Data Animal Data In an enhanced pre- and post-natal development study, pregnant cynomolgus monkeys received intravenous doses of 50 or 100 mg/kg margetuximab-cmkb once every 3 weeks starting on GD 20 and until delivery. Animal exposures at doses of 50 and 100 mg/kg were 3 and 6 times, respectively, the human exposures at the recommended dose, based on C max . Treatment with 50 and 100 mg/kg margetuximab-cmkb resulted in oligohydramnios beginning on GD 75. An infant mortality occurred on post-natal day 63 following maternal exposure to 100 mg/kg margetuximab-cmkb. Clinical findings included tubular degeneration/necrosis and tubular dilatation in the kidney. Maternal doses of 50 and 100 mg/kg resulted in decreased infant kidney weights and histologic immature nephrons. Measurable serum concentrations of margetuximab-cmkb were observed in infant animals, which is consistent with margetuximab-cmkb crossing the placenta.

8.2 Lactation Risk Summary There is no information regarding presence of MARGENZA in human milk, effects on the breastfed child, or effects on milk production. Published data suggest human IgG is present in human milk but does not enter neonatal or infant circulation in substantial amounts. Consider developmental and health benefits of breastfeeding along with the mother's clinical need for MARGENZA treatment and any potential adverse effects on the breastfed child from MARGENZA or from the underlying maternal condition. This consideration should also take into account the MARGENZA washout period of 4 months [see Clinical Pharmacology (12.3) ].

8.3 Females and Males of Reproductive Potential MARGENZA can cause fetal harm when administered to a pregnant woman. Pregnancy Testing Verify pregnancy status of females of reproductive potential prior to initiation of MARGENZA. Contraception Females Advise females of reproductive potential to use effective contraception during treatment and for 4 months following the last dose of MARGENZA [see Use in Specific Populations (8.1) and Clinical Pharmacology (12.3) ].

8.4 Pediatric Use Safety and effectiveness of MARGENZA have not been established in pediatric patients.

8.5 Geriatric Use Of the 266 patients treated with MARGENZA 20% were 65 years of age or older and 4% were 75 years or older. No overall differences in efficacy were observed between patients ≥ 65 years of age compared to younger patients. There was a higher incidence of Grade ≥ 3 adverse reactions observed in patients age 65 years or older (56%) compared to younger patients (47%), as well as adverse reactions associated with potential cardiotoxicity (35% vs 18%).

Margetuximab-cmkb binds to the extracellular domain of the human epidermal growth factor receptor 2 protein (HER2). Upon binding to HER2-expressing tumor cells, margetuximab-cmkb inhibits tumor cell proliferation, reduces shedding of the HER2 extracellular domain and mediates antibody-dependent cellular cytotoxicity (ADCC). In vitro, the modified Fc region of margetuximab-cmkb increases binding to activating Fc receptor FCGR3A (CD16A) and decreases binding to inhibitory Fc receptor FCGR2B (CD32B). These changes lead to greater in vitro ADCC and NK cell activation.