About This Calculator

The Tivdak (tisotumab vedotin) Dosing Calculator is designed to assist healthcare professionals in determining the appropriate dosage for patients based on FDA-approved prescribing information. It simplifies the process by calculating the total dose, required volume for infusion, and the number of vials needed, considering patient weight and specific dose levels.

Calculator Outputs Explained

After entering the patient’s information, the calculator provides the following key outputs for administration:

• Calculated Total Dose (mg): The total amount of tisotumab vedotin to be administered, calculated as patient weight (kg) multiplied by the selected dose rate (mg/kg). The weight used for calculation is capped at 100 kg.
• Total Volume to Administer (mL): The final volume required for the intravenous infusion, based on the reconstituted concentration of 20 mg/mL.
• Number of 40 mg Vials Needed: The minimum number of single-dose vials (40 mg) required to prepare the calculated total dose. This value is rounded up to the nearest whole number.

How to Use the Calculator

Follow these steps to determine the correct Tivdak dosage:

1. Enter Patient Weight: Input the patient’s current weight into the designated field.
2. Select Weight Unit: Choose the appropriate unit of measurement, either kilograms (kg) or pounds (lbs). The calculator will automatically convert lbs to kg for the calculation.
3. Select Dose Level: Choose the appropriate dose rate from the dropdown menu (2 mg/kg, 1.3 mg/kg, or 1 mg/kg) based on the patient’s treatment plan and tolerance.
4. Calculate: Click the “Calculate Dose” button to view the results. The outputs will be displayed instantly for clinical review.

Dosing Overview

The standard recommended dosage of Tivdak is 2 mg/kg, administered as a 30-minute intravenous infusion every 3 weeks. The dose is calculated based on the patient’s actual body weight up to a maximum of 100 kg. For patients weighing more than 100 kg, the dose should be calculated using a weight of 100 kg.

Dose reductions to 1.3 mg/kg (first reduction) and 1 mg/kg (second reduction) are recommended for managing certain adverse reactions. Clinicians should consult the full prescribing information for detailed guidance on dose modifications.

Switching Therapies

Decisions regarding the initiation of Tivdak, or switching to or from other therapies, should be made by a qualified healthcare professional. This decision should be based on a comprehensive clinical evaluation, including disease progression, patient tolerance of previous treatments, and overall health status. This tool does not provide guidance on switching treatment protocols.

Missed Dose Protocol

If a planned dose of Tivdak is missed, it should be administered as soon as possible. The schedule for subsequent doses should be adjusted accordingly to maintain the 3-week interval between infusions. Consult the full prescribing information for specific instructions on managing deviations from the recommended dosing schedule.

Safety Alerts

Frequently Asked Questions (FAQ)

Why does the calculator cap the patient weight at 100 kg?

The prescribing information for Tivdak specifies that for patients weighing more than 100 kg, the dose should be calculated using a weight of 100 kg. The calculator adheres to this guideline to prevent dosing above the clinically evaluated maximum.

How does the calculator handle weight entered in pounds (lbs)?

If you enter weight in pounds, the tool automatically converts it to kilograms (using the conversion factor 1 kg ≈ 2.20462 lbs) before calculating the dose, ensuring accuracy according to the mg/kg dosing regimen.

When should a reduced dose level be selected?

Reduced dose levels (1.3 mg/kg or 1 mg/kg) are intended for managing adverse reactions. The decision to reduce the dose should be based on the type and severity of the toxicity, in accordance with the guidance provided in the full prescribing information.

How is the number of vials calculated?

The total required dose in mg is divided by the amount per vial (40 mg). Since vials cannot be partially used for different patients, the result is always rounded up to the next whole number to ensure enough drug is available for preparation.

What is the concentration of Tivdak used for the volume calculation?

The calculator uses the final concentration of reconstituted Tivdak, which is 20 mg/mL, to determine the total volume to be administered to the patient.

Does this tool account for dose adjustments due to renal or hepatic impairment?

No. This calculator does not provide recommendations for dose adjustments based on organ function. Please refer to the specific sections on use in special populations in the full prescribing information.

What is the recommended infusion time for Tivdak?

Tivdak should be administered as an intravenous infusion over a period of 30 minutes.

Can I use this tool for any other antibody-drug conjugates?

No. This calculator is specifically designed for Tivdak (tisotumab vedotin) only. Using it for any other medication will result in incorrect and potentially unsafe dosing calculations.

References

The information and calculations provided by this tool are based on the following high-authority sources. Users must consult the full prescribing information before clinical use.

1. TIVDAK (tisotumab vedotin-tftv) Prescribing Information – U.S. Food and Drug Administration (FDA)
2. Tivdak HCP Official Website – Dosing & Administration – Seagen Inc. and Genmab A/S
3. Drugs@FDA: TIVDAK (tisotumab vedotin-tftv) – FDA Entry
4. Tivdak (tisotumab vedotin) – European Medicines Agency (EMA)