Denosumab-Qbde

1 INDICATIONS AND USAGE Enoby is a RANK ligand (RANKL) inhibitor indicated for treatment: of postmenopausal women with osteoporosis at high risk for fracture ( 1.1 ) to increase bone mass in men with osteoporosis at high risk for fracture ( 1.2 ) of glucocorticoid-induced osteoporosis in men and women at high risk for fracture ( 1.3 ) to increase bone mass in men at high risk for fracture receiving androgen deprivation therapy for nonmetastatic prostate cancer ( 1.4 ) to increase bone mass in women at high risk for fracture receiving adjuvant aromatase inhibitor therapy for breast cancer ( 1.5 ) 1.1 Treatment of Postmenopausal Women with Osteoporosis at High Risk for Fracture Enoby is indicated for the treatment of postmenopausal women with osteoporosis at high risk for fracture, defined as a history of osteoporotic fracture, or multiple risk factors for fracture; or patients who have failed or are intolerant to other available osteoporosis therapy. In postmenopausal women with osteoporosis, denosumab reduces the incidence of vertebral, nonvertebral, and hip fractures [see Clinical Studies (14.1) ] . 1.2 Treatment to Increase Bone Mass in Men with Osteoporosis Enoby is indicated for treatment to increase bone mass in men with osteoporosis at high risk for fracture, defined as a history of osteoporotic fracture, or multiple risk factors for fracture; or patients who have failed or are intolerant to other available osteoporosis therapy [see Clinical Studies (14.2) ] . 1.3 Treatment of Glucocorticoid-Induced Osteoporosis Enoby is indicated for the treatment of glucocorticoid-induced osteoporosis in men and women at high risk of fracture who are either initiating or continuing systemic glucocorticoids in a daily dosage equivalent to 7.5 mg or greater of prednisone and expected to remain on glucocorticoids for at least 6 months. High risk of fracture is defined as a history of osteoporotic fracture, multiple risk factors for fracture, or patients who have failed or are intolerant to other available osteoporosis therapy [see Clinical Studies (14.3) ] . 1.4 Treatment of Bone Loss in Men Receiving Androgen Deprivation Therapy for Prostate Cancer Enoby is indicated as a treatment to increase bone mass in men at high risk for fracture receiving androgen deprivation therapy (ADT) for nonmetastatic prostate cancer. In these patients denosumab also reduced the incidence of vertebral fractures [see Clinical Studies (14.4) ] . 1.5 Treatment of Bone Loss in Women Receiving Adjuvant Aromatase Inhibitor Therapy for Breast Cancer Enoby is indicated as a treatment to increase bone mass in women at high risk for fracture receiving adjuvant aromatase inhibitor therapy for breast cancer [see Clinical Studies (14.5) ] .

2 DOSAGE AND ADMINISTRATION Pregnancy must be ruled out prior to administration of Enoby. ( 2.1 ) Before initiating Enoby in patients with advanced chronic kidney disease, including dialysis patients, evaluate for the presence of chronic kidney disease mineral and bone disorder with intact parathyroid hormone, serum calcium, 25(OH) vitamin D, and 1,25(OH) 2 vitamin D. ( 2.2 , 5.1 , 8.6 ) Enoby should be administered by a healthcare provider. ( 2.3 ) Administer 60 mg every 6 months as a subcutaneous injection in the upper arm, upper thigh, or abdomen. ( 2.3 ) Instruct patients to take calcium 1000 mg daily and at least 400 IU vitamin D daily. ( 2.3 ) 2.1 Pregnancy Testing Prior to Initiation of Enoby Pregnancy must be ruled out prior to administration of Enoby. Perform pregnancy testing in all females of reproductive potential prior to administration of Enoby. Based on findings in animals, denosumab products can cause fetal harm when administered to pregnant women [see Use in Specific Populations (8.1 , 8.3) ] . 2.2 Laboratory Testing in Patients with Advanced Chronic Kidney Disease Prior to Initiation of Enoby In patients with advanced chronic kidney disease [i.e., estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m 2 ], including dialysis-dependent patients, evaluate for the presence of chronic kidney disease mineral and bone disorder (CKD-MBD) with intact parathyroid hormone (iPTH), serum calcium, 25(OH) vitamin D, and 1,25 (OH) 2 vitamin D prior to decisions regarding Enoby treatment. Consider also assessing bone turnover status (serum markers of bone turnover or bone biopsy) to evaluate the underlying bone disease that may be present [see Warnings and Precautions (5.1) ] . 2.3 Recommended Dosage Enoby should be administered by a healthcare provider. The recommended dose of Enoby is 60 mg administered as a single subcutaneous injection once every 6 months. Administer Enoby via subcutaneous injection in the upper arm, the upper thigh, or the abdomen. All patients should receive calcium 1000 mg daily and at least 400 IU vitamin D daily [see Warnings and Precautions (5.1) ] . If a dose of Enoby is missed, administer the injection as soon as the patient is available. Thereafter, schedule injections every 6 months from the date of the last injection. 2.4 Preparation and Administration Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. Enoby is a clear to slightly opalescent, colorless to pale yellow solution. Do not use if the solution is discolored or cloudy or if the solution contains particles or foreign particulate matter. Prior to administration, Enoby may be removed from the refrigerator and brought to room temperature up to 25°C (77°F) by standing in the original container. This generally takes 15 to 30 minutes. Do not warm Enoby in any other way [see How Supplied/Storage and Handling (16) ] . Instructions for Administration of Enoby Prefilled Syringe with Needle Safety Guard IMPORTANT: In order to minimize accidental needlesticks, the Enoby single-dose prefilled syringe has a clear safety guard that activates automatically to cover the needle after the injection is given. DO NOT attempt to activate the clear safety guard prior to administering the injection; it will lock in place and prevent injection. Step 1: Remove Gray Needle Cap (Figure A) Figure A Step 2: Administer Subcutaneous Injection Choose an injection site (Figure B). The recommended injection sites for Enoby include: the upper arm OR the upper thigh OR the abdomen. Do not press the plunger while inserting the needle. Figure B Do not administer into muscle or blood vessel. Pinch the skin and insert at a 45 to 90-degree angle. Push the plunger with slow and constant pressure all the way down until you feel or hear a “snap” (Figure C). Figure C Step 3: Release Plunger and Dispose of Syringe Keeping the prefilled syringe at the injection site, release the thumb from the plunger and lift syringe. The syringe safety guard will automatically cover the injection needle (Figure D). Figure D Immediately dispose of the syringe and needle cap in the nearest sharps container. Do not put the needle cap back on the used syringe. Enoby Before Use Enoby After Use Enoby Figure A Enoby - Figure B Enoby Figure D Enoby Figure E

6 ADVERSE REACTIONS The following serious adverse reactions are discussed below and also elsewhere in the labeling: Severe Hypocalcemia and Mineral Metabolism Changes [see Warnings and Precautions (5.1) ] Hypersensitivity [see Warnings and Precautions (5.3) ] Osteonecrosis of the Jaw [see Warnings and Precautions (5.4) ] Atypical Subtrochanteric and Diaphyseal Femoral Fractures [see Warnings and Precautions (5.5) ] Multiple Vertebral Fractures (MVF) Following Treatment Discontinuation [see Warnings and Precautions (5.6) ] Serious Infections [see Warnings and Precautions (5.7) ] Dermatologic Adverse Reactions [see Warnings and Precautions (5.8) ] The most common adverse reactions reported with denosumab products in patients with postmenopausal osteoporosis are back pain, pain in extremity, musculoskeletal pain, hypercholesterolemia, and cystitis. The most common adverse reactions reported with denosumab products in men with osteoporosis are back pain, arthralgia, and nasopharyngitis. The most common adverse reactions reported with denosumab products in patients with glucocorticoid-induced osteoporosis are back pain, hypertension, bronchitis, and headache. The most common (per patient incidence ≥ 10%) adverse reactions reported with denosumab products in patients with bone loss receiving androgen deprivation therapy for prostate cancer or adjuvant aromatase inhibitor therapy for breast cancer are arthralgia and back pain. Pain in extremity and musculoskeletal pain have also been reported in clinical trials. The most common adverse reactions leading to discontinuation of denosumab products in patients with postmenopausal osteoporosis are back pain and constipation. Postmenopausal osteoporosis: Most common adverse reactions (> 5% and more common than placebo) were: back pain, pain in extremity, hypercholesterolemia, musculoskeletal pain, and cystitis. Pancreatitis has been reported in clinical trials. ( 6.1 ) Male osteoporosis: Most common adverse reactions (> 5% and more common than placebo) were: back pain, arthralgia, and nasopharyngitis. ( 6.1 ) Glucocorticoid-induced osteoporosis: Most common adverse reactions (> 3% and more common than active-control group) were: back pain, hypertension, bronchitis, and headache. ( 6.1 ) Bone loss due to hormone ablation for cancer: Most common adverse reactions (≥ 10% and more common than placebo) were: arthralgia and back pain. Pain in extremity and musculoskeletal pain have also been reported in clinical trials. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Hikma Pharmaceuticals USA Inc. at 1-877-845-0689 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice. Treatment of Postmenopausal Women with Osteoporosis The safety of denosumab in the treatment of postmenopausal osteoporosis was assessed in a 3-year, randomized, double-blind, placebo-controlled, multinational study of 7808 postmenopausal women aged 60 to 91 years. A total of 3876 women were exposed to placebo and 3886 women were exposed to denosumab administered subcutaneously once every 6 months as a single 60 mg dose. All women were instructed to take at least 1000 mg of calcium and 400 IU of vitamin D supplementation per day. The incidence of all-cause mortality was 2.3% (n = 90) in the placebo group and 1.8% (n = 70) in the denosumab group. The incidence of nonfatal serious adverse events was 24.2% in the placebo group and 25.0% in the denosumab group. The percentage of patients who withdrew from the study due to adverse events was 2.1% and 2.4% for the placebo and denosumab groups, respectively. The most common adverse reactions reported with denosumab in patients with postmenopausal osteoporosis are back pain, pain in extremity, musculoskeletal pain, hypercholesterolemia, and cystitis. Adverse reactions reported in ≥ 2% of postmenopausal women with osteoporosis and more frequently in the denosumab-treated women than in the placebo-treated women are shown in the table below. Table 1. Adverse Reactions Occurring in ≥ 2% of Patients with Osteoporosis and More Frequently than in Placebo-treated Patients Preferred Term Denosumab (N = 3886) n (%) Placebo (N = 3876) n (%) Back pain 1347 (34.7) 1340 (34.6) Pain in extremity 453 (11.7) 430 (11.1) Musculoskeletal pain 297 (7.6) 291 (7.5) Hypercholesterolemia 280 (7.2) 236 (6.1) Cystitis 228 (5.9) 225 (5.8) Vertigo 195 (5.0) 187 (4.8) Upper respiratory tract infection 190 (4.9) 167 (4.3) Edema peripheral 189 (4.9) 155 (4.0) Sciatica 178 (4.6) 149 (3.8) Bone pain 142 (3.7) 117 (3.0) Abdominal pain upper 129 (3.3) 111 (2.9) Anemia 129 (3.3) 107 (2.8) Insomnia 126 (3.2) 122 (3.1) Myalgia 114 (2.9) 94 (2.4) Angina pectoris 101 (2.6) 87 (2.2) Rash 96 (2.5) 79 (2.0) Pharyngitis 91 (2.3) 78 (2.0) Asthenia 90 (2.3) 73 (1.9) Pruritus 87 (2.2) 82 (2.1) Flatulence 84 (2.2) 53 (1.4) Spinal osteoarthritis 82 (2.1) 64 (1.7) Gastroesophageal reflux disease 80 (2.1) 66 (1.7) Herpes zoster 79 (2.0) 72 (1.9) Hypocalcemia Decreases in serum calcium levels to less than 8.5 mg/dL at any visit were reported in 0.4% women in the placebo group and 1.7% women in the denosumab group. The nadir in serum calcium level occurred at approximately day 10 after denosumab dosing in subjects with normal renal function. In clinical studies, subjects with impaired renal function were more likely to have greater reductions in serum calcium levels compared to subjects with normal renal function. In a study of 55 subjects with varying degrees of renal function, serum calcium levels < 7.5 mg/dL or symptomatic hypocalcemia were observed in 5 subjects. These included no subjects in the normal renal function group, 10% of subjects in the creatinine clearance 50 to 80 mL/min group, 29% of subjects in the creatinine clearance < 30 mL/min group, and 29% of subjects in the hemodialysis group. These subjects did not receive calcium and vitamin D supplementation. In a study of 4550 postmenopausal women with osteoporosis, the mean change from baseline in serum calcium level 10 days after denosumab dosing was -5.5% in subjects with creatinine clearance < 30 mL/min vs. -3.1% in subjects with creatinine clearance ≥ 30 mL/min. Serious Infections Receptor activator of nuclear factor kappa-B ligand (RANKL) is expressed on activated T and B lymphocytes and in lymph nodes. Therefore, a RANKL inhibitor such as denosumab products may increase the risk of infection. In the clinical study of 7808 postmenopausal women with osteoporosis, the incidence of infections resulting in death was 0.2% in both placebo and denosumab treatment groups. However, the incidence of nonfatal serious infections was 3.3% in the placebo and 4.0% in the denosumab groups. Hospitalizations due to serious infections in the abdomen (0.7% placebo vs. 0.9% denosumab), urinary tract (0.5% placebo vs. 0.7% denosumab), and ear (0.0% placebo vs. 0.1% denosumab) were reported. Endocarditis was reported in no placebo patients and 3 patients receiving denosumab. Skin infections, including erysipelas and cellulitis, leading to hospitalization were reported more frequently in patients treated with denosumab (< 0.1% placebo vs. 0.4% denosumab). The incidence of opportunistic infections was similar to that reported with placebo. Dermatologic Adverse Reactions A significantly higher number of patients treated with denosumab developed epidermal and dermal adverse events (such as dermatitis, eczema, and rashes), with these events reported in 8.2% of the placebo and 10.8% of the denosumab groups (p < 0.0001). Most of these events were not specific to the injection site [see Warnings and Precautions (5.8) ] . Osteonecrosis of the Jaw ONJ has been reported in the osteoporosis clinical trial program in patients treated with denosumab [see Warnings and Precautions (5.4) ] . Atypical Subtrochanteric and Diaphyseal Femoral Fractures In the osteoporosis clinical trial program, atypical femoral fractures were reported in patients treated with denosumab. The duration of denosumab exposure to time of atypical femoral fracture diagnosis was as early as 2 1/2 ; years [see Warnings and Precautions (5.5) ] . Multiple Vertebral Fractures (MVF) Following Treatment Discontinuation In the osteoporosis clinical trial program, multiple vertebral fractures were reported in patients after discontinuation of denosumab. In the phase 3 trial in women with postmenopausal osteoporosis, 6% of women who discontinued denosumab and remained in the study developed new vertebral fractures, and 3% of women who discontinued denosumab and remained in the study developed multiple new vertebral fractures. The mean time to onset of multiple vertebral fractures was 17 months (range: 7-43 months) after the last injection of denosumab. Prior vertebral fracture was a predictor of multiple vertebral fractures after discontinuation [see Warnings and Precautions (5.6) ] . Pancreatitis Pancreatitis was reported in 4 patients (0.1%) in the placebo and 8 patients (0.2%) in the denosumab groups. Of these reports, 1 patient in the placebo group and all 8 patients in the denosumab group had serious events, including one death in the denosumab group. Several patients had a prior history of pancreatitis. The time from product administration to event occurrence was variable. New Malignancies The overall incidence of new malignancies was 4.3% in the placebo and 4.8% in the denosumab groups. New malignancies related to the breast (0.7% placebo vs. 0.9% denosumab), reproductive system (0.2% placebo vs. 0.5% denosumab), and gastrointestinal system (0.6% placebo vs. 0.9% denosumab) were reported. A causal relationship to drug exposure has not been established. Treatment to Increase Bone Mass in Men with Osteoporosis The safety of denosumab in the treatment of men with osteoporosis was assessed in a 1-year randomized, double-blind, placebo-controlled study. A total of 120 men were exposed to placebo and 120 men were exposed to denosumab administered subcutaneously once every 6 months as a single 60 mg dose. All men were instructed to take at least 1000 mg of calcium and 800 IU of vitamin D supplementation per day. The incidence of all-cause mortality was 0.8% (n = 1) in the placebo group and 0.8% (n = 1) in the denosumab group. The incidence of nonfatal serious adverse events was 7.5% in the placebo group and 8.3% in the denosumab group. The percentage of patients who withdrew from the study due to adverse events was 0% and 2.5% for the placebo and denosumab groups, respectively. Adverse reactions reported in ≥ 5% of men with osteoporosis and more frequently with denosumab than in the placebo-treated patients were: back pain (6.7% placebo vs. 8.3% denosumab), arthralgia (5.8% placebo vs. 6.7% denosumab), and nasopharyngitis (5.8% placebo vs. 6.7% denosumab). Serious Infections Serious infection was reported in 1 patient (0.8%) in the placebo group and no patients in the denosumab group. Dermatologic Adverse Reactions Epidermal and dermal adverse events (such as dermatitis, eczema, and rashes) were reported in 4 patients (3.3%) in the placebo group and 5 patients (4.2%) in the denosumab group. Osteonecrosis of the Jaw No cases of ONJ were reported. Pancreatitis Pancreatitis was reported in 1 patient (0.8%) in the placebo group and 1 patient (0.8%) in the denosumab group. New Malignancies New malignancies were reported in no patients in the placebo group and 4 (3.3%) patients (3 prostate cancers, 1 basal cell carcinoma) in the denosumab group. Treatment of Glucocorticoid-Induced Osteoporosis The safety of denosumab in the treatment of glucocorticoid-induced osteoporosis was assessed in the 1-year, primary analysis of a 2-year randomized, multicenter, double-blind, parallel-group, active-controlled study of 795 patients (30% men and 70% women) aged 20 to 94 (mean age of 63 years) treated with greater than or equal to 7.5 mg/day oral prednisone (or equivalent). A total of 384 patients were exposed to 5 mg oral daily bisphosphonate (active-control) and 394 patients were exposed to denosumab administered once every 6 months as a 60 mg subcutaneous dose. All patients were instructed to take at least 1000 mg of calcium and 800 IU of vitamin D supplementation per day. The incidence of all-cause mortality was 0.5% (n = 2) in the active-control group and 1.5% (n = 6) in the denosumab group. The incidence of serious adverse events was 17% in the active-control group and 16% in the denosumab group. The percentage of patients who withdrew from the study due to adverse events was 3.6% and 3.8% for the active-control and denosumab groups, respectively. Adverse reactions reported in ≥ 2% of patients with glucocorticoid-induced osteoporosis and more frequently with denosumab than in the active-control-treated patients are shown in the table below. Table 2. Adverse Reactions Occurring in ≥ 2% of Patients with Glucocorticoid-induced Osteoporosis and More Frequently with Denosumab than in Active-Control-treated Patients Preferred Term Denosumab (N = 394) n (%) Oral Daily Bisphosphonate (Active-Control) (N = 384) n (%) Back pain 18 (4.6) 17 (4.4) Hypertension 15 (3.8) 13 (3.4) Bronchitis 15 (3.8) 11 (2.9) Headache 14 (3.6) 7 (1.8) Dyspepsia 12 (3.0) 10 (2.6) Urinary tract infection 12 (3.0) 8 (2.1) Abdominal pain upper 12 (3.0) 7 (1.8) Upper respiratory tract infection 11 (2.8) 10 (2.6) Constipation 11 (2.8) 6 (1.6) Vomiting 10 (2.5) 6 (1.6) Dizziness 9 (2.3) 8 (2.1) Fall 8 (2.0) 7 (1.8) Polymyalgia rheumatica* 8 (2.0) 1 (0.3) *Events of worsening of underlying polymyalgia rheumatica. Osteonecrosis of the Jaw No cases of ONJ were reported. Atypical Subtrochanteric and Diaphyseal Femoral Fractures Atypical femoral fractures were reported in 1 patient treated with denosumab. The duration of denosumab exposure to time of atypical femoral fracture diagnosis was at 8.0 months [see Warnings and Precautions (5.5) ] . Serious Infections Serious infection was reported in 15 patients (3.9%) in the active-control group and 17 patients (4.3%) in the denosumab group. Dermatologic Adverse Reactions Epidermal and dermal adverse events (such as dermatitis, eczema, and rashes) were reported in 16 patients (4.2%) in the active-control group and 15 patients (3.8%) in the denosumab group. Treatment of Bone Loss in Patients Receiving Androgen Deprivation Therapy for Prostate Cancer or Adjuvant Aromatase Inhibitor Therapy for Breast Cancer The safety of denosumab in the treatment of bone loss in men with nonmetastatic prostate cancer receiving androgen deprivation therapy (ADT) was assessed in a 3-year, randomized, double-blind, placebo-controlled, multinational study of 1468 men aged 48 to 97 years. A total of 725 men were exposed to placebo and 731 men were exposed to denosumab administered once every 6 months as a single 60 mg subcutaneous dose. All men were instructed to take at least 1000 mg of calcium and 400 IU of vitamin D supplementation per day. The incidence of serious adverse events was 30.6% in the placebo group and 34.6% in the denosumab group. The percentage of patients who withdrew from the study due to adverse events was 6.1% and 7.0% for the placebo and denosumab groups, respectively. The safety of denosumab in the treatment of bone loss in women with nonmetastatic breast cancer receiving aromatase inhibitor (AI) therapy was assessed in a 2-year, randomized, double-blind, placebo-controlled, multinational study of 252 postmenopausal women aged 35 to 84 years. A total of 120 women were exposed to placebo and 129 women were exposed to denosumab administered once every 6 months as a single 60 mg subcutaneous dose. All women were instructed to take at least 1000 mg of calcium and 400 IU of vitamin D supplementation per day. The incidence of serious adverse events was 9.2% in the placebo group and 14.7% in the denosumab group. The percentage of patients who withdrew from the study due to adverse events was 4.2% and 0.8% for the placebo and denosumab groups, respectively. Adverse reactions reported in ≥ 10% of denosumab-treated patients receiving ADT for prostate cancer or adjuvant AI therapy for breast cancer, and more frequently than in the placebo-treated patients were: arthralgia (13.0% placebo vs. 14.3% denosumab) and back pain (10.5% placebo vs. 11.5% denosumab). Pain in extremity (7.7% placebo vs. 9.9% denosumab) and musculoskeletal pain (3.8% placebo vs. 6.0% denosumab) have also been reported in clinical trials. Additionally, in denosumab-treated men with nonmetastatic prostate cancer receiving ADT, a greater incidence of cataracts was observed (1.2% placebo vs. 4.7% denosumab). Hypocalcemia (serum calcium < 8.4 mg/dL) was reported only in denosumab-treated patients (2.4% vs. 0.0%) at the month 1 visit. 6.2 Postmarketing Experience Because postmarketing 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. The following adverse reactions have been identified during post-approval use of denosumab products: Drug-related hypersensitivity reactions: anaphylaxis, rash, urticaria, facial swelling, and erythema Hypocalcemia: severe symptomatic hypocalcemia resulting in hospitalization, life-threatening events, and fatal cases Musculoskeletal pain, including severe cases Parathyroid hormone (PTH): Marked elevation in serum PTH in patients with severe renal impairment (creatinine clearance < 30 mL/min) or receiving dialysis Multiple vertebral fractures following treatment discontinuation Cutaneous and mucosal lichenoid drug eruptions (e.g., lichen planus-like reactions) Alopecia Vasculitis (e.g., ANCA positive vasculitis, leukocytoclastic vasculitis) Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome

12.3 Pharmacokinetics In a study conducted in healthy male and female volunteers (n = 73, age range: 18 to 64 years) following a single subcutaneously administered denosumab dose of 60 mg, the mean area-under-the-concentration-time curve up to 16 weeks (AUC 0-16 weeks ) of denosumab was 316 mcg•day/mL (standard deviation [SD] = 101 mcg•day/mL). The mean maximum denosumab concentration (C max ) was 6.75 mcg/mL (SD = 1.89 mcg/mL). No accumulation or change in denosumab pharmacokinetics with time is observed with multiple dosing of 60 mg subcutaneously administered once every 6 months. Absorption Following subcutaneous administration, the median time to maximum denosumab concentration (T max ) was 10 days (range: 3 to 21 days). Distribution The mean volume of distribution for denosumab was 5.2 L (SD = 1.7 L). Elimination Serum denosumab concentrations declined over a period of 4 to 5 months with a mean half-life of 25.4 days (SD = 8.5 days; n = 46). A population pharmacokinetic analysis was performed to evaluate the effects of demographic characteristics. This analysis showed no notable differences in pharmacokinetics with age (in postmenopausal women), race, or body weight (36 to 140 kg). Seminal Fluid Pharmacokinetic Study Serum and seminal fluid concentrations of denosumab were measured in 12 healthy male volunteers (age range: 43-65 years). After a single 60 mg subcutaneous administration of denosumab, the mean (± SD) C max values in the serum and seminal fluid samples were 6170 (± 2070) and 100 (± 81.9) ng/mL, respectively, resulting in a maximum seminal fluid concentration of approximately 2% of serum levels. The median (range) T max values in the serum and seminal fluid samples were 8.0 (7.9 to 21) and 21 (8.0 to 49) days, respectively. Among the subjects, the highest denosumab concentration in seminal fluid was 301 ng/mL at 22 days post-dose. On the first day of measurement (10 days post-dose), nine of eleven subjects had quantifiable concentrations in semen. On the last day of measurement (106 days post-dose), five subjects still had quantifiable concentrations of denosumab in seminal fluid, with a mean (± SD) seminal fluid concentration of 21.1 (± 36.5) ng/mL across all subjects (n = 12). Drug Interactions In a study of 19 postmenopausal women with low BMD and rheumatoid arthritis treated with etanercept (50 mg subcutaneous injection once weekly), a single-dose of denosumab (60 mg subcutaneous injection) was administered 7 days after the previous dose of etanercept. No clinically significant changes in the pharmacokinetics of etanercept were observed. Cytochrome P450 substrates In a study of 17 postmenopausal women with osteoporosis, midazolam (2 mg oral) was administered 2 weeks after a single-dose of denosumab (60 mg subcutaneous injection), which approximates the T max of denosumab. Denosumab did not affect the pharmacokinetics of midazolam, which is metabolized by cytochrome P450 3A4 (CYP3A4). This indicates that denosumab products should not alter the pharmacokinetics of drugs metabolized by CYP3A4 in postmenopausal women with osteoporosis. Specific Populations Gender: Mean serum denosumab concentration-time profiles observed in a study conducted in healthy men ≥ 50 years were similar to those observed in a study conducted in postmenopausal women using the same dose regimen. Age: The pharmacokinetics of denosumab were not affected by age across all populations studied whose ages ranged from 28 to 87 years. Race: The pharmacokinetics of denosumab were not affected by race. Renal Impairment: In a study of 55 patients with varying degrees of renal function, including patients on dialysis, the degree of renal impairment had no effect on the pharmacokinetics of denosumab; thus, dose adjustment for renal impairment is not necessary. Hepatic Impairment: No clinical studies have been conducted to evaluate the effect of hepatic impairment on the pharmacokinetics of denosumab products.