About This Tool

The Trodelvy (sacituzumab govitecan) Dosing Calculator is designed to assist healthcare professionals in determining the appropriate dose and administration parameters for patients. It provides outputs for total dose, vial requirements, reconstitution volume, and infusion duration based on weight and the recommended dosing schedule.

Calculator Outputs Explained

After entering patient data, the calculator provides the following key outputs for safe and accurate administration:

• Total Dose to Administer (mg): The patient-specific dose calculated by multiplying their weight in kg by the selected dose level (mg/kg).
• Number of Vials Needed: The number of 180 mg single-dose vials required to prepare the total dose. This is rounded up to the nearest whole vial.
• Reconstitution Instructions: A reminder to reconstitute each vial with 20 mL of Sterile Water for Injection, USP, to achieve a final concentration of 10 mg/mL.
• Total Volume to Withdraw (mL): The total volume of reconstituted solution needed to achieve the calculated total dose.
• Dilution Guidance: Instructions to add the withdrawn volume to a 0.9% Sodium Chloride infusion bag, targeting a final concentration between 1.1 mg/mL and 3.4 mg/mL.
• Infusion Duration: The recommended time for the intravenous infusion, which is 3 hours for the initial dose and 1-2 hours for subsequent doses, if tolerated.

How to Use the Calculator

Follow these steps to ensure accurate calculations:

1. Enter Patient Weight: Input the patient's current body weight. You can select the unit of measurement (kg or lbs). The tool will automatically convert lbs to kg for the calculation.
2. Select Dose Level: Choose the appropriate dose from the dropdown menu. Options include the standard 10 mg/kg dose and the first (7.5 mg/kg) and second (5 mg/kg) dose reductions for managing toxicities. A custom option is also available.
3. Specify Treatment Cycle Information: Indicate whether this is the patient's first-ever infusion ("Initial Infusion") or a "Subsequent Infusion" to determine the correct infusion duration.
4. Calculate: The tool will process the inputs and display the full dosing and preparation details.

Dosing Overview

The recommended dosage of Trodelvy is 10 mg/kg administered as an intravenous infusion once weekly on Days 1 and 8 of a 21-day treatment cycle. Treatment should continue until disease progression or unacceptable toxicity. Do not administer Trodelvy if the absolute neutrophil count (ANC) is below 1500/mm³ on Day 1 or below 1000/mm³ on Day 8 of any cycle, or if neutropenic fever occurs.

Dose Modifications and Reductions

Dose reductions are required for patients experiencing certain adverse reactions. This tool includes presets for the recommended dose reduction levels. The decision to reduce a dose should be based on clinical judgment and the severity and persistence of the toxicity, in line with the full prescribing information.

• First Dose Reduction: Reduce the dose to 7.5 mg/kg.
• Second Dose Reduction: Further reduce the dose to 5 mg/kg.
• Discontinuation: If a patient requires a further dose reduction below 5 mg/kg, treatment with Trodelvy should be permanently discontinued.

Managing a Missed Dose

If a planned dose of Trodelvy is missed, it should be administered as soon as possible. The weekly administration schedule should be adjusted to maintain a 7-day interval between doses. For example, if a Day 8 dose is delayed, the next cycle should begin 2 weeks after the rescheduled Day 8 dose is administered to maintain the 21-day cycle length.

Safety Alerts

Frequently Asked Questions

What is the concentration of Trodelvy after reconstitution?

After reconstituting a 180 mg vial with 20 mL of Sterile Water for Injection, USP, the resulting concentration is 10 mg/mL.

Why is the initial infusion longer than subsequent infusions?

The initial infusion is administered over 3 hours to monitor for and manage any potential infusion-related reactions. If the first dose is well-tolerated, subsequent infusions can be given over a shorter period of 1 to 2 hours.

What should I do if the calculated dose is slightly more than what one vial provides?

You must use an additional vial. The calculator automatically determines the minimum number of whole vials needed. You will reconstitute the required number of vials and withdraw the precise volume needed for the total calculated dose.

Does this calculator account for dose holds?

No, this calculator does not provide guidance on when to hold a dose. Dosing should be held for an ANC below 1500/mm³ (Day 1) or 1000/mm³ (Day 8), or for other severe toxicities as outlined in the prescribing information.

Can I use this calculator for pediatric patients?

The safety and effectiveness of Trodelvy have not been established in pediatric patients. This tool should only be used for adult patients according to the approved indications.

What is the final concentration range for the diluted infusion solution?

After adding the required volume of reconstituted Trodelvy to the infusion bag (0.9% Sodium Chloride), the final concentration must be between 1.1 mg/mL and 3.4 mg/mL.

How should reconstituted or diluted Trodelvy be stored?

The reconstituted vial and the diluted infusion solution should be refrigerated at 2°C to 8°C (36°F to 46°F) and used within 4 hours. Do not freeze.

What does the "Custom Dose" option do?

The "Custom Dose" option allows for dose calculations based on a specific mg/kg value that is not one of the standard predefined levels. This may be used in clinical trial settings or other specific clinical scenarios as directed by a protocol, but should not replace standard dose modification guidelines.

References

1. TRODELVY® (sacituzumab govitecan-hziy) [Prescribing Information]. Foster City, CA: Gilead Sciences, Inc. Updated April 2023. Accessed from FDA.gov.
2. Gilead Oncology. Trodelvy HCP Website. Dosing & Administration. Accessed from trodelvyhcp.com.
3. U.S. Food and Drug Administration (FDA). Highlights of Prescribing Information for TRODELVY. Available at: FDA Drugs@FDA.
4. National Cancer Institute (NCI). Sacituzumab Govitecan-hziy. NCI Drug Dictionary. Accessed from cancer.gov.