Study of TST002 Injection in Postmenopausal Women With Osteoporosis or Low Bone Mass

Primary Purpose: Efficacy and safety evaluation of TST002 in postmenopausal osteoporosis and low bone mass. Design: 5-arm, randomized, double-blind (denosumab arm open-label), placebo- and active-comparator (denosumab)-controlled, parallel-group study with stratified block randomization by screening BMD T-score (Stratum 1: T-score ≥ -2.00; Stratum 2: T-score \< -2.00 at all sites). Enrollment capped at \<20% Stratum 1 participants per arm. All participants receive daily calcium (600-1200 mg elemental) and vitamin D (725-1450 IU) supplementation from screening through study end, with an optional vitamin D loading dose for those with baseline 25(OH)D 20-40 ng/mL. Unblinding: Primary analysis after all participants complete Week 24 is performed by an unblinded CRO team; investigators, participants, and the CRO study team (except for the open-label denosumab arm) remain blinded until final study unblinding