About This Guidance

This information supports the use of the Imfinzi (durvalumab) Dosing Calculator. It provides an overview of dosing regimens, administration details, and answers to frequently asked questions based on the approved prescribing information. This content is for informational purposes and should not replace clinical judgment or the full prescribing information.

Calculator Outputs Explained

Upon entering the required patient data, the calculator provides the following key outputs for the selected indication and schedule:

• Total Calculated Dose: The precise dose of Imfinzi in milligrams (mg) to be administered.
• Dosing Schedule: The frequency of administration (e.g., every 2, 3, or 4 weeks).
• Infusion Volume: The total volume of medication in milliliters (mL) to be prepared for intravenous infusion, based on a standard concentration of 50 mg/mL.
• Contextual Notes: Important reminders specific to the indication, such as combination therapy requirements or weight-based restrictions.

How to Use the Calculator

Follow these simple steps to determine the correct dosing information:

1. Select Indication: Choose the appropriate FDA-approved indication from the dropdown menu.
2. Enter Patient Weight: Input the patient’s current weight and select the unit (kg or lbs). The tool will automatically convert to kilograms for calculation.
3. Select Dosing Schedule (if applicable): For certain indications (e.g., Stage III NSCLC in patients ≥30 kg), a choice between dosing schedules will appear. Select the desired regimen.
4. Calculate: Click the “Calculate Dose” button to view the results. The “Reset” button will clear all fields.

Dosing Overview by Indication

Imfinzi dosing varies significantly by indication and patient weight. All doses are administered as a 60-minute intravenous infusion.

Unresectable Stage III NSCLC

• Patients ≥ 30 kg: Two options are available. Either 10 mg/kg every 2 weeks OR a fixed dose of 1500 mg every 4 weeks.
• Patients < 30 kg: The only recommended dose is 10 mg/kg every 2 weeks. The fixed-dose Q4W schedule is not approved for this weight group.

Extensive-Stage SCLC (ES-SCLC)

• Induction (First 4 Cycles): Fixed dose of 1500 mg every 3 weeks in combination with etoposide and either carboplatin or cisplatin.
• Maintenance (Following Induction): Fixed dose of 1500 mg every 4 weeks as a single agent.

Biliary Tract Cancer (BTC)

• A fixed dose of 1500 mg every 3 weeks is given in combination with gemcitabine and cisplatin. After chemotherapy completion, Imfinzi can be continued as monotherapy at 1500 mg every 4 weeks.

Unresectable Hepatocellular Carcinoma (uHCC)

• This is part of the STRIDE regimen. On Cycle 1, Day 1, a single 300 mg dose of tremelimumab-actl is administered, followed by a 1500 mg dose of Imfinzi.
• Subsequent cycles consist of Imfinzi 1500 mg monotherapy every 4 weeks.

Switching Dosing Schedules

For patients with Stage III NSCLC weighing ≥ 30 kg, it is possible to switch between the 10 mg/kg Q2W schedule and the 1500 mg Q4W schedule. When switching, the first dose of the new schedule should be administered at the time the next dose of the previous schedule was planned. Healthcare providers should consult the full prescribing information for specific guidance on transitioning patients.

Missed Dose Information

If a planned dose of Imfinzi is missed, it should be administered as soon as possible. The administration schedule should then be adjusted to maintain the appropriate dosing interval between doses.

• For Q2W schedules, if the next dose is due within 7 days, administer the missed dose and resume the original schedule.
• For Q3W and Q4W schedules, if the next dose is due within 14 days, administer the missed dose and resume.

Always refer to the prescribing information for detailed instructions, as the correct action may vary based on the regimen.

Safety Alerts and Disclaimers

Frequently Asked Questions (FAQ)

References

1. IMFINZI® (durvalumab) injection, for intravenous use. Full Prescribing Information, AstraZeneca; 2022. View at FDA.gov
2. Drugs@FDA: FDA-Approved Drugs – Imfinzi (durvalumab). accessdata.fda.gov
3. IMFINZI® Official Healthcare Professional Website. imfinzihcp.com
4. Durvalumab – NCI Drug Dictionary. National Cancer Institute. cancer.gov