This study has been designed as a randomized, double-blind, parallel-group study and in healthy adult male subjects of age 28 years to 55 years old. The study will assess the PK, safety and tolerability of AVT03 compared to US-Xgeva when administered as a single 120 mg SC dose

The study will consist of screening period, a 196 day (28 weeks) treatment and assessment period, and an End of Study (EOS) visit on week 32 on Day 196. Subjects will undertake a screening visit between Day -28 and Day -1 to determine their eligibility for the study. Subjects who meet the eligibility criteria will be admitted to the study site on the day prior to dosing (Day -1), during which their continued eligibility will be assessed up to Day 1 prior to dosing. On Day 1, eligible subjects will be randomized and will receive a single dose of 120mg AVT03 or 120mg Xgeva as subcutaneous injection.

Inclusion Criteria:

1. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.
2. Male subjects who are 28 to 55 years old, inclusive, at the time of signing the ICF.
3. Have a body weight of 50.0 to 90.0 kg (inclusive) and body mass index of 17.0 to 32 kg/m2 at Screening and Day -1.

Exclusion Criteria:

1. Evidence of clinically relevant pathology, especially prior diagnosis of bone disease, or any uncontrolled condition that will affect bone metabolism such as, but not limited to: osteoporosis, osteogenesis imperfecta, hyperparathyroidism,, non-controlled hyperthyroidism osteomalacia, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, current flare-up of osteoarthritis and/or gout, active malignancy, renal disease, Paget's disease of the bone, malabsorption syndrome.
2. Have osteonecrosis of the jaw (ONJ) or risk factors for ONJ such as invasive dental procedures (e.g., tooth extraction, dental implants, oral surgery) or intend to undergo such procedures during the study period, poor oral hygiene, periodontal, and/or pre-existing dental disease.
3. Have bone fractures, presence of active healing fractures, or recent bone fracture
4. Abnormal serum calcium.
5. Known vitamin D deficiency.

Participants were healthy males aged 28 to 55 years.

All AEs/SAEs were recorded from the time of signing the ICF until the end of the subject's participation in the study, up to 32 weeks.

Double Blind