PTH-Like Peptides for Osteoporosis and Hypoparathyroidism Treatment
For osteoporosis treatment, teriparatide (PTH 1-34) is strongly recommended for patients at very high risk of fracture, while for hypoparathyroidism, PTH analogues should be considered only after optimizing conventional therapy with calcium and vitamin D supplements. 1, 2
PTH-Like Peptides for Osteoporosis
Patient Selection and Indications
- Teriparatide is indicated for:
- Postmenopausal women with osteoporosis at high risk for fracture
- Men with primary or hypogonadal osteoporosis at high risk for fracture
- Men and women with glucocorticoid-induced osteoporosis at high risk for fracture
- Patients who have failed or are intolerant to other available osteoporosis therapy 2
Treatment Algorithm for Osteoporosis
- First-line therapy: Oral bisphosphonates for most patients with osteoporosis 3
- Consider teriparatide for very high-risk patients:
- Prior osteoporotic fracture(s)
- BMD T-score ≤−3.5
- FRAX (GC-Adjusted) 10-year risk of major osteoporotic fracture ≥30% or hip ≥4.5%
- High glucocorticoid use ≥30 mg/day for >30 days or cumulative doses ≥5 g/year 1
Dosing and Administration
- Recommended dose: 20 mcg subcutaneously once daily 2
- Administer as evening subcutaneous injections into thigh or abdominal region
- Initial administration should be done where patient can sit or lie down if orthostatic hypotension occurs
- Treatment duration: Up to 2 years maximum during a patient's lifetime 2
- Consider supplemental calcium and vitamin D based on individual needs
Monitoring During Treatment
- Clinic visits every 3-6 months to monitor:
- Bone mineral density
- Serum calcium levels (particularly after 1 month of treatment)
- Response to therapy
- Adverse effects 4
Post-Treatment Considerations
- After completing teriparatide treatment, transition to an antiresorptive agent (typically a bisphosphonate) to maintain bone density gains 4, 5
PTH-Like Peptides for Hypoparathyroidism
For hypoparathyroidism, conventional therapy remains the mainstay of treatment:
Conventional Treatment Approach
- Elemental phosphorus: 20–60mg/kg body weight daily (0.7–2.0mmol/kg daily) in infants and preschool children 1
- Frequency: 4–6 times daily initially, can be reduced to 3–4 times daily when alkaline phosphatase normalizes
- Calcitriol: 20–30ng/kg body weight daily or alfacalcidol 30–50ng/kg body weight daily 1
Management of Secondary Hyperparathyroidism
- For elevated PTH levels: Increase dose of active vitamin D and/or decrease oral phosphate supplements
- Calcimimetics might be considered for persistent secondary hyperparathyroidism
- Parathyroidectomy for tertiary hyperparathyroidism 1
Safety Considerations and Contraindications
Contraindications for Teriparatide
- Hypersensitivity to teriparatide or its excipients
- Patients at increased risk for osteosarcoma:
- Open epiphyses
- Metabolic bone diseases including Paget's disease
- Bone metastases or history of skeletal malignancies
- Prior radiation therapy involving the skeleton
- Hereditary disorders predisposing to osteosarcoma 2
Adverse Effects to Monitor
- Hypercalcemia (typically mild and transient)
- Orthostatic hypotension (particularly with initial doses)
- Nausea, pain, and arthralgia (most common side effects)
- Urolithiasis (consider risk/benefit in patients with active or recent urolithiasis) 2
Special Populations
- Pregnancy: Consider discontinuing when pregnancy is recognized
- Breastfeeding: Not recommended
- Pediatric patients: Safety and effectiveness not established; avoid use due to increased baseline risk of osteosarcoma
- Renal impairment: Use with caution; AUC and half-life increased by 73% and 77% in severe renal impairment 2
Comparative Efficacy
- Teriparatide has demonstrated a 65% reduction in vertebral fractures and 35% reduction in non-vertebral fractures in postmenopausal women 6, 5
- Moderate-to-severe fractures or multiple vertebral fractures could be reduced by 90% and 77%, respectively 6
- Direct comparison with alendronate revealed that teriparatide has a more pronounced effect on bone mineral density 5
By following this treatment algorithm and carefully selecting appropriate patients, PTH-like peptides can significantly reduce fracture risk and improve bone quality in those with severe osteoporosis or manage hypoparathyroidism when conventional therapy is insufficient.