Prospective, randomized, multicentre study to compare the efficacy at 52 weeks (1 year) of biosimilar teriparatide and alendronate in the prevention of new morphometric vertebral fractures and/or worsening of previous vertebral fractures in women with a clinical vertebral fracture or recent hip fracture (imminent risk of fracture) caused by bone fragility.

You likely can't join if

• 1. Hypercalcaemia. 2. Severe vitamin D deficiency (25-hydroxyvitamin D < 10 ng/ml). If the serum concentration of 25-hydroxyvitamin D is 10-30 ng/ml, the patient may be included, but rapid supplementation with cholecalciferol or calcifediol will be carried out according to standard clinical practice. 3. Primary hyperparathyroidism. 4. Paget's disease of bone. 5. Contraindication to any of the treatments in the study. 6. Unexplained parathyroid hormone (PTH) elevation or alkaline phosphatase (ALP). 7. Previous use of intravenous zoledronate in the 52 weeks before inclusion in the study, intravenous ibandronate or pamidronate in the 3 months before inclusion in the study, denosumab in the 52 weeks before inclusion in the study, or prior use of the parathyroid hormone, teriparatide, another analog hormone or sodium fluoride at therapeutic doses at any time. Previous treatment with other antiosteoporotic drugs is permitted, provided that they are not being taken at the time of inclusion in the study. 8. Having received at least 1 dose of romosozumab at any previous time. 9. Patients who, for any reason (cognitive, socio-economic, etc.), have particular difficulties adhering to treatment 10. Having suffered two or more previous vertebral fractures* 11. Patients who, due to their characteristics and according to the doctor's criteria, could benefit more from treatment for osteoporosis other than those in the study, such as denosumab or zoledronic acid** * in these patients, it might be more justified to treat with teriparatide rather than with bisphosphonates ** denosumab might be preferable in patients with renal insufficiency, documented intolerance or contraindication to oral bisphosphonates, polypharmacy or who prefer subcutaneous administration every 6 months to daily treatment; zoledronic acid may be preferable in patients with documented intolerance or contraindication to oral bisphosphonates, polypharmacy, and bedridden patients or those with severe functional impairment.