Pegvisomant

1 INDICATIONS AND USAGE SOMAVERT is indicated for the treatment of acromegaly in patients who have had an inadequate response to surgery or radiation therapy, or for whom these therapies are not appropriate. The goal of treatment is to normalize serum insulin-like growth factor-1 (IGF-1) levels. SOMAVERT is a growth hormone receptor antagonist indicated for the treatment of acromegaly in patients who have had an inadequate response to surgery or radiation therapy, or for whom these therapies are not appropriate. The goal of treatment is to normalize serum insulin-like growth factor-1 (IGF-1) levels. ( 1 )

2 DOSAGE AND ADMINISTRATION • Administer a 40 mg loading dose subcutaneously under physician supervision. ( 2.1 ) • After proper injection instruction, on day after loading dose, patients or caregivers begin daily subcutaneous injections of 10 mg. ( 2.1 ) • Adjust dosage in 5 mg increments or decrements until serum IGF-1 concentrations are maintained within age-adjusted normal range. Do not adjust dosage based on growth hormone (GH) levels or signs or symptoms of acromegaly. ( 2.1 ) • Dosage range is 10 mg to 30 mg once daily. ( 2.1 ) • Perform liver tests prior to first dosage and if greater than 3 times upper limit of normal should work-up prior to SOMAVERT administration. ( 2.2 ) • Follow reconstitution and injection procedures. ( 2.3 , 2.4 ) 2.1 Dosage Information The recommended loading dose of SOMAVERT is 40 mg given subcutaneously, under healthcare provider supervision. Provide proper training in subcutaneous injection technique to patients or their caregivers so they can receive once daily subcutaneous injections. On the next day following the loading dose, instruct patients or their caregivers to begin daily subcutaneous injections of 10 mg of SOMAVERT. Titrate the dosage to normalize serum IGF-1 concentrations (serum IGF-1 concentrations should be measured every four to six weeks). The dosage should not be based on growth hormone (GH) concentrations or signs and symptoms of acromegaly. It is unknown whether patients who remain symptomatic while achieving normalized IGF-1 concentrations would benefit from increased SOMAVERT dosage. • Increase the dosage by 5 mg increments every 4–6 weeks if IGF-1 concentrations are elevated. • Decrease the dosage by 5 mg decrements every 4–6 weeks if IGF-1 concentrations are below the normal range. • IGF-1 levels should also be monitored when a SOMAVERT dose given in multiple injections is converted to a single daily injection [see Clinical Pharmacology (12) ] . The recommended dosage range is between 10 mg to 30 mg given subcutaneously once daily and the maximum daily dosage is 30 mg given subcutaneously once daily. 2.2 Assess Liver Tests Prior to Initiation of SOMAVERT Prior to the start of SOMAVERT, patients should have an assessment of baseline levels of liver tests [serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum total bilirubin (TBIL), and alkaline phosphatase (ALP)]. For recommendations regarding initiation of SOMAVERT based on baseline liver tests and recommendations for monitoring of liver tests while on SOMAVERT, refer to Table 1 in Warning and Precautions (5.2) . 2.3 Loading Dose Injection Procedure The following instructions are for the healthcare provider to reconstitute and prepare the 40 mg loading dose. The healthcare provider will need to reconstitute 2 vials of lyophilized powder of SOMAVERT each containing 20 mg of pegvisomant with supplied diluent [two vials of lyophilized powder and two syringes containing 1 mL of diluent (Sterile Water for Injection, USP) will be needed for the 40 mg loading dose]. The healthcare provider will also need to inject the reconstituted SOMAVERT solution twice into the patient's upper arm, upper thigh, abdomen, or buttocks (each injection in a different area). a) Before administering the loading dose, remove 1 vial of lyophilized powder of SOMAVERT containing 20 mg of pegvisomant and one syringe containing 1 mL of diluent from the refrigerator, if refrigerated, about 10 minutes prior to the planned injection time. b) Reconstitute the first 20 mg vial of lyophilized powder of SOMAVERT containing 20 mg of pegvisomant with diluent. When using the diluent in the syringe, inject the contents of the syringe slowly onto the sides of the vial containing lyophilized powder of SOMAVERT. Do not inject the diluent directly on the powder. c) Do not invert the vial or shake the solution as this may cause denaturation of the pegvisomant protein. Slowly swirl the solution to ensure that all of the lyophilized powder has gone into solution. If foaming of the reconstituted SOMAVERT solution is seen, the solution is likely damaged and therefore inappropriate to inject. d) Visually inspect the reconstituted SOMAVERT solution for particulate matter and discoloration prior to administration. The reconstituted solution should be clear. If the solution is cloudy, do not use it. Once reconstituted, the solution will contain 20 mg of pegvisomant in 1 mL of solution. e) Withdraw the 1 mL reconstituted SOMAVERT solution. The solution must be administered immediately after reconstitution. f) Inject the first reconstituted SOMAVERT solution (20 mg/mL) subcutaneously into the patient's upper arm, upper thigh, abdomen, or buttocks using a 90-degree angle. g) Repeat steps (a) to (e) to reconstitute the second SOMAVERT dose of 20mg. h) Finally, inject the second reconstituted SOMAVERT solution (20 mg/mL) subcutaneously into the patient's upper arm, upper thigh, abdomen, or buttocks using a 90-degree angle (different area than the first injection). 2.4 Maintenance Dose Injection Procedure For patient or caregiver instructions for reconstitution and administration of daily doses (10 mg to 30 mg), see the Patient's Instructions for Use . a) Before administering the dose, remove 1 vial of lyophilized powder of SOMAVERT containing 10 mg, 15 mg, 20 mg, 25 mg or 30 mg of pegvisomant and one syringe containing 1 mL of diluent from the refrigerator, if refrigerated, about 10 minutes prior to the planned injection time. b) Reconstitute the lyophilized powder of SOMAVERT with diluent. When using the diluent in the 2.25 mL syringe, inject the contents of the syringe slowly onto the sides of the vial containing lyophilized powder of SOMAVERT. Do not inject the diluent directly on the powder. c) Do not invert the vial or shake the solution as this may cause denaturation of the pegvisomant protein. Slowly swirl the solution to ensure that all of the lyophilized powder has gone into solution. If foaming of the reconstituted SOMAVERT solution is seen, the solution is likely damaged and therefore inappropriate to inject. d) Visually inspect the reconstituted SOMAVERT solution for particulate matter and discoloration prior to administration. The reconstituted solution should be clear. If the solution is cloudy, do not use it. Once reconstituted, the solution will contain 10 mg, 15 mg, 20 mg, 25 mg or 30 mg of pegvisomant in 1 mL of solution. e) Withdraw the 1 mL reconstituted SOMAVERT solution. The solution must be administered immediately after reconstitution. f) Inject the reconstituted SOMAVERT solution subcutaneously into the upper arm, upper thigh, abdomen, or buttocks using a 90-degree angle.

6 ADVERSE REACTIONS Clinically significant adverse reactions that appear in other section of the labeling include: • Hypoglycemia Associated with GH Lowering in Patients with Diabetes Mellitus [see Warnings and Precautions (5.1) ] • Liver Toxicity [see Warnings and Precautions (5.2) ] • Cross-Reactivity with GH Assays [see Warnings and Precautions (5.3) ] • Lipohypertrophy [see Warnings and Precautions (5.4) ] • Systemic Hypersensitivity [see Warnings and Precautions (5.5) ] Elevations of serum concentrations of ALT and AST greater than ten times the ULN were reported in two patients (0.8%) exposed to SOMAVERT in pre-approval clinical studies. One patient was rechallenged with SOMAVERT, and the recurrence of elevated transaminase levels suggested a probable causal relationship between administration of the drug and the elevation in liver enzymes. A liver biopsy performed on the second patient was consistent with chronic hepatitis of unknown etiology. In both patients, the transaminase elevations normalized after discontinuation of the drug. Elevations in ALT and AST levels were not associated with increased levels of TBIL and ALP, with the exception of two patients with minimal associated increases in ALP levels (i.e., less than 3 times ULN). The transaminase elevations did not appear to be related to the dose of SOMAVERT administered, generally occurred within 4 to 12 weeks of initiation of therapy, and were not associated with any identifiable biochemical, phenotypic, or genetic predictors. Most common reported adverse reactions (>6%) are infection, pain, nausea, diarrhea, abnormal liver tests, flu syndrome, injection site reaction. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc. at 1-800-438-1985 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. In a 12-week randomized, placebo-controlled, double-blind, fixed-dose study of SOMAVERT in subjects with acromegaly, 32 subjects received placebo and 80 subjects received SOMAVERT once daily [see Clinical Studies (14) ] . A total of 108 subjects (30 placebo, 78 SOMAVERT) completed 12 weeks of study treatment. Overall, eight patients with acromegaly (5.3%) withdrew from pre-marketing clinical studies because of adverse events, including two patients with marked transaminase elevations, one patient with lipohypertrophy at the injection sites, and one patient with substantial weight gain. Most adverse events did not appear to be dose-dependent. Table 3 shows the incidence of adverse events that were reported in at least two patients treated with SOMAVERT and at frequencies greater than placebo during the 12-week, placebo-controlled study. Table 3. Adverse Reactions in a 12-week Placebo-Controlled Study in Patients with Acromegaly Table includes only those events that were reported in at least 2 patients and at a higher incidence in patients treated with SOMAVERT than in patients treated with placebo. Placebo n=32 SOMAVERT 10 mg/day n=26 15 mg/day n=26 20 mg/day N=28 Infection The 6 events coded as "infection" in the group treated with SOMAVERT 10 mg were reported as cold symptoms (3), upper respiratory infection (1), blister (1), and ear infection (1). The 2 events in the placebo group were reported as cold symptoms (1) and chest infection (1). 2 (6%) 6 (23%) 0 0 Pain 2 (6%) 2 (8%) 1 (4%) 4 (14%) Nausea 1 (3%) 0 2 (8%) 4 (14%) Diarrhea 1 (3%) 1 (4%) 0 4 (14%) Abnormal liver function tests 1 (3%) 3 (12%) 1 (4%) 1 (4%) Flu syndrome 0 1 (4%) 3 (12%) 2 (7%) Injection site reaction 0 2 (8%) 1 (4%) 3 (11%) Dizziness 2 (6%) 2 (8%) 1 (4%) 1 (4%) Accidental injury 1 (3%) 2 (8%) 1 (4%) 0 Back pain 1 (3%) 2 (8%) 0 1 (4%) Sinusitis 1 (3%) 2 (8%) 0 1 (4%) Chest pain 0 1 (4%) 2 (8%) 0 Peripheral edema 0 2 (8%) 0 1 (4%) Hypertension 0 0 2 (8%) 0 Paresthesia 2 (6%) 0 0 2 (7%) 6.2 Postmarketing Experience Adverse Reactions from Postmarketing Spontaneous Reports The following adverse reactions have been identified during post-approval use of SOMAVERT. 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. Systemic hypersensitivity reactions including anaphylactic reactions, laryngospasm, angioedema, generalized skin reactions (rash, erythema, pruritus, urticaria) have been reported in post-marketing use. Some patients required hospitalization. Symptoms did not re-occur in all patients after re-challenge [see Warnings and Precautions (5.5) ] . Adverse Reactions from an Observational Study ACROSTUDY was an international observational registry that captured long term safety data in 2221 patients with acromegaly treated with SOMAVERT for a mean treatment duration of 8.5 years. Patients could also receive other therapy for acromegaly during the registry period. Treatment dose and schedule were at the discretion of each treating healthcare provider. Although safety monitoring as per the recommended schedule was mandatory, not all assessments were performed at all time points for every patient. Because of this, comparison of rates of adverse events to those in the original clinical trial is not appropriate. Of the 1327 patients who had a normal AST and ALT at baseline, 20 (1.5%) patients had elevated tests >3-5 times ULN, and 22 (1.7%) patients had elevated tests >5 times ULN. Lipohypertrophy was reported in 35 (1.6%) patients. Of the 1795 patients who had a MRI reported at baseline and at least once during follow up in the study, MRI results showed that 128 (7.1%) were reported to have an increase, 310 (17.3%) were reported to have a decrease, 81 (4.5%) had both increase and decrease, and 1276 (71.1%) had no change.

12.3 Pharmacokinetics Absorption: Following subcutaneous administration, peak serum pegvisomant concentrations are not generally attained until 33 to 77 hours after administration. The mean extent of absorption of a 20-mg subcutaneous dose was 57%, relative to a 10-mg intravenous dose. Distribution: The mean apparent volume of distribution of pegvisomant is 7 L (12% coefficient of variation), suggesting that pegvisomant does not distribute extensively into tissues. After a single subcutaneous administration, exposure (C max , AUC) to pegvisomant increases disproportionately with increasing dose. Mean ± SEM serum pegvisomant concentrations after 12 weeks of therapy with daily doses of 10, 15, and 20 mg were 6600 ± 1330; 16,000 ± 2200; and 27,000 ± 3100 ng/mL, respectively. The relative bioavailability of 1 × 30 mg pegvisomant was compared to 2 × 15 mg pegvisomant in a single-dose study. The AUC inf and C max of pegvisomant when administered as one injection of 30 mg strength was approximately 6% and 4% greater, respectively, as compared to when administered as two injections of 15 mg strengths. Metabolism and Elimination: The pegvisomant molecule contains covalently bound polyethylene glycol polymers in order to reduce the clearance rate. Clearance of pegvisomant following multiple doses is lower than seen following a single-dose. The mean total body systemic clearance of pegvisomant following multiple doses is estimated to range between 36 to 28 mL/h for subcutaneous doses ranging from 10 to 20 mg/day, respectively. Clearance of pegvisomant was found to increase with body weight. Pegvisomant is eliminated from serum with a mean half-life estimates ranging from 60 to 138 hours following either single or multiple doses. Less than 1% of administered drug is recovered in the urine over 96 hours. The elimination route of pegvisomant has not been studied in humans. Drug Interaction Studies In clinical studies, patients on opioids often needed higher serum pegvisomant concentrations to achieve appropriate IGF-1 suppression compared with patients not receiving opioids. The mechanism of this interaction is not known [see Drug Interactions (7.2) ] . Specific Populations No pharmacokinetic studies have been conducted in patients with renal impairment, patients with hepatic impairment, geriatric patients, or pediatric patients and the effects of race on the pharmacokinetics of pegvisomant has not been studied. No gender effect on the pharmacokinetics of pegvisomant was found in a population pharmacokinetic analysis.