About

This section provides detailed information about the clinical parameters and outputs of the Tymlos (abaloparatide) Dosing Calculator. It explains the calculations performed, the inputs required, and provides an overview of dosing, safety, and administration based on prescribing information.

Outputs

The calculator provides the following key outputs to support clinical decision-making:

• Renal Function Assessment: Calculates creatinine clearance (CrCl) using the Cockcroft-Gault equation and estimated glomerular filtration rate (eGFR) using the 2021 CKD-EPI equation. It also provides the corresponding CKD stage.
• Therapy Duration Tracker: Calculates the total cumulative lifetime exposure to PTH and PTHrP analogs (e.g., Tymlos, teriparatide) and displays the remaining allowable therapy duration based on the 2-year lifetime limit.
• Clinical Alerts: Generates specific warnings for patients with severe renal impairment (CrCl or eGFR <30 mL/min) and for those approaching or exceeding the 24-month cumulative therapy limit.

How to Use

To use the calculator, a healthcare professional must enter the following patient data:

1. Age, Weight, and Biological Sex: Essential inputs for calculating renal function.
2. Serum Creatinine (SCr): A direct measure of kidney function, required for both CrCl and eGFR calculations.
3. Tymlos Therapy Start Date: Used to determine the duration of the current course of therapy.
4. Prior PTH/PTHrP Analog Use: A “Yes” or “No” selection to indicate previous treatment with drugs like teriparatide.
5. Duration of Prior Therapy: If prior use is indicated, the total number of months of that therapy must be entered to calculate total lifetime exposure.

Dosing Overview

The recommended dosage of Tymlos is 80 mcg administered subcutaneously once daily in the periumbilical region. The total duration of treatment with Tymlos and other PTH or PTHrP analogs should not exceed 2 years over a patient’s lifetime. No dose adjustment is specified for mild, moderate, or severe renal impairment, but caution is advised in patients with severe renal impairment due to potential for increased drug exposure and adverse events like hypercalcemia.

Switching

When switching a patient to Tymlos from another PTH or PTHrP analog (e.g., teriparatide), the duration of the prior therapy must be counted toward the 2-year cumulative lifetime limit. For example, a patient who has completed 18 months of teriparatide therapy has a maximum of 6 months of Tymlos therapy remaining.

Missed Dose

If a dose of Tymlos is missed, the patient should not take an extra dose to make up for the missed one. They should resume their once-daily dosing schedule with the next planned dose.

Safety Alerts

• Black Box Warning (Osteosarcoma): Abaloparatide caused a dose-dependent increase in osteosarcoma in rat studies. The relevance to humans is unknown. Due to this risk, the cumulative lifetime use of Tymlos and other similar agents is limited to 2 years.
• Severe Renal Impairment: Use with caution in patients with severe renal impairment (CrCl <30 mL/min). Monitor for signs of hypercalcemia.
• Orthostatic Hypotension: May occur within 4 hours of the first several doses. Administer in a setting where the patient can sit or lie down if necessary.
• Hypercalcemia: Tymlos can cause hypercalcemia. It is contraindicated in patients with pre-existing hypercalcemia.

FAQ

References

1. TYMLOS (abaloparatide) Injection – Full Prescribing Information. U.S. Food and Drug Administration.
2. TYMLOS® (abaloparatide) for Healthcare Professionals. Radius Health, Inc.
3. Inker LA, Eneanya ND, Coresh J, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737-1749.
4. Miller PD, Hattersley G, Riis BJ, et al. Effect of Abaloparatide vs Teriparatide on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial. JAMA. 2016;316(7):722–733.