Patient description: The patient is a 53-year-old man complaining of frequent headaches, generalized bone pain and difficulty chewing that started 6 years ago and is getting worse. Examination shows bilateral swellings around the molars. The swellings have increased since his last examination. Several extraoral lesions of the head and face are detected. The swellings are non-tender and attached to the underlying bone. Further evaluation shows increased uptake of radioactive substance as well as an increase in urinary pyridinoline. The serum alkaline phosphatase is 300 IU/L (the normal range is 44- 147 IU/L). The patient's sister had the same problems. She was diagnosed with Paget's disease of bone when she was 52 years old. The diagnosis of Paget's Disease of Bone is confirmed and Bisphosphonate will be started as first-line therapy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-65.0,  Healthy Volunteer Key Healthy male and female, ages ≥ 18 to ≤ 65 years (inclusive) Body weight > 60 to < 100 kg at time of screening Clinically acceptable physical exams and laboratory tests (blood hematology, blood chemistry, urinalysis) and no history or evidence of any clinically significant medical disorder that would pose a risk to subject safety or interfere with study evaluations or procedures Normal or clinically acceptable electrocardiogram (ECG) (12-lead reporting heart rate and PR, QRS, QT, and QTc intervals) at screening Willing to be confined to the research facility for 2 consecutive nights Subject will be available for follow-up assessments  Prior diagnosis of bone disease, or any condition that will affect bone metabolism such as, but not limited to: osteoporosis, osteogenesis imperfecta, hyperparathyroidism, hyperthyroidism, hypothyroidism, osteomalacia, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, current flare-up of osteoarthritis and/or gout, active malignancy, renal disease (defined as glomerular filtration rate [GFR] < 45 mL/min), Paget's disease of the bone, recent bone fracture (within 6 months), malabsorption syndrome Presents with any psychiatric disorder, which may prevent the subject from completing the study or interfere with the interpretation of the study results Significant changes in physical activity during the 6 months before study drug administration or constant levels of intense physical exercise Prior use of any non-Amgen approved medications within 4 weeks or 5-half lives (whichever time period is longer) of study drug administration and for the duration of the study. This includes medications such as, but not limited to: bisphosphonates, fluoride, hormone replacement therapy (ie, estrogen) or selective estrogen receptor modulator, such as ralaxofene, calcitonin, strontium, parathyroid hormone or derivatives, supplemental vitamin D [>1000 IU/day], glucocorticosteroids, anabolic steroids, calcitriol, diuretics, over the counter medications, herbal supplements Positive for human immunodeficiency virus (HIV) at screening or known diagnosis of acquired immune deficiency syndrome (AIDS) Positive hepatitis B surface antigen (HepBsAg) (indicative of chronic hepatitis B) or detectable hepatitis C virus ribonucleic acid (RNA) by polymerase chain reaction (PCR) at screening (indicative of active hepatitis C screening is generally done by hepatitis C antibody [HepCAb], followed by hepatitis C virus RNA by PCR if HepCAb is positive) Known sensitivity to any of the products to be administered during the study Prior denosumab administration Receiving or has received any investigational drug (or is currently using an investigational device) within 30 days before receiving study drug, or at least 10 times the respective elimination half-life (whichever period is longer) and for the duration of the study