Can Forteo (teriparatide) be used in patients with Chronic Renal Failure (CRF) and elevated Parathyroid Hormone (PTH) levels?

Use of Forteo (Teriparatide) in Patients with Chronic Renal Failure and Elevated PTH Levels

Forteo (teriparatide) is generally not recommended for patients with chronic renal failure (CRF) and elevated parathyroid hormone (PTH) levels due to the risk of worsening secondary hyperparathyroidism and potential adverse effects on bone metabolism.

Contraindications and Concerns

• Patients with CRF already have disturbed calcium and phosphorus metabolism, with secondary hyperparathyroidism being a common complication that requires careful management 1
• Teriparatide stimulates bone formation and bone resorption markers, which could potentially exacerbate existing mineral and bone disorders in CRF patients 2
• The FDA label for teriparatide does not specifically address its use in patients with elevated PTH levels, but notes that in 5 patients with severe renal impairment (CrCl<30 mL/minute), the AUC and half-life of teriparatide were increased by 73% and 77%, respectively 2
• Clinical practice guidelines for growth hormone treatment in children with CKD specifically recommend stopping treatment in patients with persistent severe secondary hyperparathyroidism (PTH >500 pg/ml) 1

Bone Metabolism in CRF

• CRF patients develop secondary hyperparathyroidism due to phosphorus retention, decreased calcium absorption, and reduced vitamin D activation 3
• Management of bone disease in CRF focuses on controlling phosphorus levels, maintaining normal calcium levels, and preventing excessive PTH secretion 1
• Bone biopsy may be necessary to accurately diagnose the type of renal osteodystrophy present (hyperparathyroid bone disease, adynamic bone disease, osteomalacia, or mixed uremic osteodystrophy) 1
• PTH levels between 100-500 pg/mL in CRF patients may not reliably predict the underlying bone disease, making treatment decisions challenging 1

Evidence for Teriparatide in CRF

• There is very limited evidence regarding teriparatide use in CRF patients with elevated PTH levels
• One case report showed successful use of teriparatide in a hemodialysis patient with low-turnover bone disease, resulting in improved bone formation parameters and fracture healing 4
• However, this single case involved a patient with low-turnover bone disease, not the high-turnover state typically seen with elevated PTH 4
• The pharmacokinetics of teriparatide are altered in severe renal impairment, with increased exposure that could potentially increase risks 2

Alternative Management Approaches

• For CRF patients with elevated PTH levels, the standard approach includes:
  • Phosphate binders to control serum phosphorus levels 1
  • Vitamin D sterols (calcitriol or analogs) to suppress PTH secretion 1
  • Calcimimetics for persistent secondary hyperparathyroidism 1
  • Parathyroidectomy for severe, refractory cases 1
• Careful monitoring of calcium, phosphorus, and PTH levels is essential during treatment 1

Conclusion

Based on the available evidence and clinical guidelines, teriparatide should be avoided in patients with CRF and elevated PTH levels. The potential risks include worsening of secondary hyperparathyroidism, altered mineral metabolism, and unpredictable effects on bone due to the already disturbed PTH physiology in these patients. Management should instead focus on established treatments for secondary hyperparathyroidism in CRF.