Metreleptin

12.1 Mechanism of Action Adipocytes store lipids to meet the fuel requirements of non-adipose tissues during fasting. In patients with generalized lipodystrophy, the deficiency of adipose tissue leads to hypertriglyceridemia and ectopic deposition of fat in non-adipose tissues such as liver and muscle, contributing to metabolic abnormalities including insulin resistance. Native leptin is a hormone predominantly secreted by adipose tissue that informs the central nervous system of the status of energy stores in the body. In patients with generalized lipodystrophy, leptin deficiency, resulting from the loss of adipose tissue, contributes to excess caloric intake, which exacerbates the metabolic abnormalities. MYALEPT (metreleptin) for injection exerts its function by binding to and activating the human leptin receptor (ObR), which belongs to the Class I cytokine family of receptors that signals through the JAK/STAT transduction pathway.

1 INDICATIONS AND USAGE MYALEPT is a leptin analog indicated as an adjunct to diet as replacement therapy to treat the complications of leptin deficiency in patients with congenital or acquired generalized lipodystrophy. ( 1 ) Limitations of Use The safety and effectiveness of MYALEPT for the treatment of complications of partial lipodystrophy have not been established. ( 1 ) The safety and effectiveness of MYALEPT for the treatment of liver disease, including nonalcoholic steatohepatitis (NASH), have not been established. ( 1 ) MYALEPT is not indicated for use in patients with HIV-related lipodystrophy. ( 1 ) MYALEPT is not indicated for use in patients with metabolic disease, without concurrent evidence of generalized lipodystrophy. ( 1 ) 1.1 Patients with Generalized Lipodystrophy MYALEPT (metreleptin) for injection is indicated as an adjunct to diet as replacement therapy to treat the complications of leptin deficiency in patients with congenital or acquired generalized lipodystrophy. Limitations of Use The safety and effectiveness of MYALEPT for the treatment of complications of partial lipodystrophy have not been established. The safety and effectiveness of MYALEPT for the treatment of liver disease, including nonalcoholic steatohepatitis (NASH), have not been established. MYALEPT is not indicated for use in patients with HIV-related lipodystrophy. MYALEPT is not indicated for use in patients with metabolic disease, including diabetes mellitus and hypertriglyceridemia, without concurrent evidence of congenital or acquired generalized lipodystrophy.

2 DOSAGE AND ADMINISTRATION Administer as a subcutaneous injection once daily after the lyophilized cake is reconstituted with Bacteriostatic Water for Injection (BWFI) or preservative-free sterile Water for Injection (WFI). ( 2.1 ) The recommended daily dosages are: Body weight 40 kg or less: starting dose 0.06 mg/kg/day, increase or decrease by 0.02 mg/kg to a maximum daily dose of 0.13 mg/kg. ( 2.1 ) Males greater than 40 kg body weight: starting dose 2.5 mg/day, increase or decrease by 1.25 mg to 2.5 mg/day to a maximum dose of 10 mg/day. ( 2.1 ) Females greater than 40 kg body weight: starting dose 5 mg/day, increase or decrease by 1.25 mg to 2.5 mg/day to a maximum dose of 10 mg/day. ( 2.1 ) 2.1 Recommended Dosing See Table 1 for the recommended daily dose and maximum recommended daily dose in adults and pediatric patients. Based on clinical response (e.g., inadequate metabolic control) or other considerations (e.g., tolerability issues, excessive weight loss [especially in pediatric patients]), MYALEPT dosage may be decreased or increased to the maximum dosage listed in Table 1. Table 1: MYALEPT Recommended Dosage Baseline weight Starting daily dose (injection volume) Dose adjustments (injection volume) Maximum daily dose (injection volume) Less than or equal to 40 kg (males and females) 0.06 mg/kg (0.012 mL/kg) 0.02 mg/kg (0.004 mL/kg) 0.13 mg/kg (0.026 mL/kg) Males greater than 40 kg 2.5 mg (0.5 mL) 1.25 mg (0.25 mL) to 2.5 mg (0.5 mL) 10 mg (2 mL) Females greater than 40 kg 5 mg (1 mL) 1.25 mg (0.25 mL) to 2.5 mg (0.5 mL) 10 mg (2 mL) In pediatric patients, small volumes for administration can result in medication errors when measured incorrectly [see Dosage and Administration (2.3) , Adverse Reactions (6.3) ] . Table 2 provides example doses and volumes by weight . For patients using insulin syringes, the volume conversion is 100 Units/mL. Table 2: Example Dosing Chart for Patients Less than or Equal to 40 kg Weight Starting Dose Dose Adjustment Maximum Dose 5 kg 0.30 mg (0.06 mL or 6 Units) 0.10 mg (0.02 mL or 2 Units) 0.65 mg (0.13 mL or 13 Units) 10 kg 0.60 mg (0.12 mL or 12 Units) 0.20 mg (0.04 mL or 4 Units) 1.3 mg (0.26 mL or 26 Units) 15 kg 0.90 mg (0.18 mL or 18 Units) 0.30 mg (0.06 mL or 6 Units) 1.95 mg (0.39 mL or 39 Units) 20 kg 1.2 mg (0.24 mL or 24 Units) 0.40 mg (0.08 mL or 8 Units) 2.6 mg (0.52 mL or 52 Units) 25 kg 1.5 mg (0.3 mL or 30 Units) 0.50 mg (0.1 mL or 10 Units) 3.25 mg (0.65 mL or 65 Units) 30 kg 1.8 mg (0.36 mL or 36 Units) 0.60 mg (0.12 mL or 12 Units) 3.9 mg (0.78 mL or 78 Units) 35 kg 2.1 mg (0.42 mL or 42 Units) 0.70 mg (0.14 mL or 14 Units) 4.55 mg (0.91 mL or 91 Units) 40 kg 2.4 mg (0.48 mL or 48 Units) 0.80 mg (0.16 mL or 16 Units) 5.2 mg (1.03 mL or 103 Units) MYALEPT should be administered once daily at the same time every day. MYALEPT can be administered any time of day without regard to the timing of meals. Instruct patients that if a dose is missed, administer the dose as soon as noticed, and resume the normal dosing schedule the next day. 2.2 MYALEPT Preparation and Storage Healthcare practitioners should provide proper training to patients and caregivers regarding how to prepare and administer the correct dose of MYALEPT prior to self-use. The patients and caregivers should prepare and administer the first dose of MYALEPT under the supervision of a qualified healthcare professional. Instruct patients to store the vials of lyophilized powder in their carton in the refrigerator as soon as received [see How Supplied/Storage and Handling (16.2) ]. MYALEPT can be reconstituted aseptically with 2.2 mL of sterile Bacteriostatic Water for Injection (BWFI), USP (0.9% benzyl alcohol), or with 2.2 mL of sterile Water for Injection (WFI). When reconstituted in BWFI, MYALEPT solution can be used within 3 days when stored in the refrigerator between 36°F and 46°F (2°C and 8°C) and protected from light [see How Supplied/Storage and Handling (16.2) ]. Discard unused reconstituted solution after 3 days. Attach the supplied sticker to the vial and enter the discard date. For use in neonates and infants, reconstitute with preservative-free sterile WFI [see Warnings and Precautions (5.7) and Use in Specific Populations (8.4) ]. When reconstituted in sterile WFI, MYALEPT should be administered immediately. Unused reconstituted solution cannot be saved for later use and should be discarded. Reconstitution of the Lyophilized Powder Instruct patients to follow the directions below for reconstitution of the lyophilized powder: Remove the vial containing the MYALEPT lyophilized powder from the refrigerator and allow the vial to warm to room temperature prior to use. Visually inspect the vial containing MYALEPT. The cake of lyophilized powder should be intact and white in color. Using a 3-mL syringe with a 22-gauge or smaller diameter needle withdraw 2.2 mL of sterile Bacteriostatic Water for Injection (BWFI) or preservative-free sterile Water for Injection (WFI). Do not reconstitu

6 ADVERSE REACTIONS Most common in clinical trials (≥10%): headache, hypoglycemia, decreased weight, abdominal pain. ( 5.4 , 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Amryt Pharmaceuticals DAC at 1-855-303-2347 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. Open-Label, Single-Arm Study The safety of MYALEPT was evaluated in 48 patients with generalized lipodystrophy in a single-arm, open-label study [see Clinical Studies (14.1) ]. The median duration of exposure in this trial was 2.7 years with a range of 3.6 months to 10.9 years. The most frequent adverse reactions are summarized in Table 3. Table 3: Adverse Reactions of 5% or Greater Incidence in Patients with Generalized Lipodystrophy Receiving MYALEPT in an Open-Label, Single-Arm Study All Subjects N=48 (%) 1. Hypoglycemic events were assessed as mild, moderate, severe, or life threatening based on the protocol specified definitions: Mild: Documentation of low plasma glucose values with no symptoms; Moderate: Presence of clinical symptoms requiring ingestion of glucose, self-alleviated; Severe: Presence of neuroglycopenic symptoms requiring assistance from others for alleviation; Life threatening: Loss of consciousness and/or requiring intervention by administration of intravenous glucose or intramuscular glucagon. Headache 6 (13) Hypoglycemia 1 6 (13) Decreased weight 6 (13) Abdominal pain 5 (10) Arthralgia 4 (8) Dizziness 4 (8) Ear infection 4 (8) Fatigue 4 (8) Nausea 4 (8) Ovarian cyst 4 (8) Upper respiratory tract infection 4 (8) Anemia 3 (6) Back pain 3 (6) Diarrhea 3 (6) Paresthesia 3 (6) Proteinuria 3 (6) Pyrexia 3 (6) In patients with generalized lipodystrophy receiving MYALEPT in this study, less common adverse reactions included injection-site erythema and urticaria (N=2 [4%]). Six patients (13%) had 7 adverse reactions of hypoglycemia, 6 of which occurred in the setting of concomitant insulin use, with or without oral antihyperglycemic agents. Two patients (4%) had events of pancreatitis, both of whom had a medical history of pancreatitis. 6.2 Immunogenicity As with all therapeutic proteins, there is potential for immunogenicity. Anti-metreleptin antibodies were detected in 84% (36/43) of generalized lipodystrophy patients studied in the MYALEPT trials. Total anti-metreleptin antibody titers ranged between 1:5 and 1:1,953,125. The incompleteness of the current immunogenicity database precludes understanding of the magnitude and persistence of the observed anti-drug antibody responses. Anti-metreleptin antibodies with neutralizing activity associated with adverse events consistent with loss of endogenous leptin activity and/or loss of MYALEPT efficacy were observed in 6% (2/33) of the patients with generalized lipodystrophy tested. Adverse events reported in these two patients included severe infections and worsening of metabolic control (increases in HbA 1c and/or triglycerides). Test for anti-metreleptin antibodies with neutralizing activity in patients who develop severe infections or show signs suspicious for loss of MYALEPT efficacy during treatment. Contact Amryt Pharmaceuticals DAC at 1-866-216-1526 for testing of clinical samples. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. The immunogenicity assays utilized in clinical trials lacked sensitivity, resulting in potential underestimation of the number of samples positive for anti-metreleptin antibodies with neutralizing activity. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to metreleptin with the incidence of antibodies to other products may be misleading. 6.3 Postmarketing Experience The following adverse reactions have been identified during post-approval use of MYALEPT. 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. Incorrect dose administered, accidental overdose [see Dosage and Administration (2.1 , 2.3) ] Injection site reaction, including inflammation and hyperpigmentation

7 DRUG INTERACTIONS No formal drug interaction studies were performed. Leptin is a cytokine and may have the potential to alter the formation of cytochrome P450 (CYP450) enzymes. This should be taken into account when prescribing concomitant drugs metabolized by CYP450 (e.g., oral contraceptives and drugs with a narrow therapeutic index). The effect of metreleptin on CYP450 enzymes may be clinically relevant for CYP450 substrates with narrow therapeutic index, where the dose is individually adjusted. Upon initiation or discontinuation of MYALEPT, in patients being treated with these types of agents, therapeutic monitoring of effect (e.g., warfarin) or drug concentration (e.g., cyclosporine or theophylline) should be performed and the individual dose of the agent adjusted as needed.