The overarching goal of the research program is to define optimal treatment for premenopausal
women with clinically significant fracture syndromes that require medical therapy. The
investigators hypothesize that romosozumab will be associated with improvements in bone mass
and microarchitecture in premenopausal women, and also that the responses and response rates
will exceed those observed in premenopausal women treated with teriparatide. The
investigators will test this hypothesis in this phase 2 study of 30 premenopausal women with
idiopathic osteoporosis (IOP) who will receive 12M of romosozumab 210 mg monthly followed by
12M of denosumab 60 mg SC q6M. Aim 1 will define the within-group effects of this regimen.
Aim 2 will compare results from participants treated with romosozumab-denosumab to the
investigator's well-characterized historical controls treated with teriparatide followed by
denosumab.