About This Tool

This page provides supplementary clinical information for the Sarclisa (isatuximab) Dosing Calculator. The calculator is designed to help healthcare professionals determine the appropriate dose, vial combination, and infusion rates for patients based on their weight and treatment schedule, in accordance with the prescribing information.

Calculator Outputs Explained

After entering the patient's data, the calculator provides a detailed summary for dose preparation and administration, including:

• Total Calculated Dose (mg): The patient's weight in kilograms multiplied by the standard 10 mg/kg dose.
• Drug Volume to Withdraw (mL): The total volume of Sarclisa concentrate (20 mg/mL) needed to achieve the calculated dose.
• Vial Combination: The most efficient combination of 500 mg and 100 mg vials to minimize drug wastage.
• Infusion Parameters: The total infusion volume (standard 250 mL), final drug concentration in the bag, and a schedule-specific table of infusion rates.

How to Use the Calculator

To use the tool effectively, follow these steps:

1. Enter Patient Weight: Input the patient's body weight. You can select the unit of measurement (kg or lbs); the calculator will automatically convert to kg for the dose calculation.
2. Select Treatment Schedule: Choose the appropriate infusion schedule from the dropdown menu. The selection determines the infusion rate protocol, as the first two infusions have a slower, escalating rate to manage potential reactions.
3. Calculate: Click the "Calculate Dose" button to generate the complete dosing and administration plan.

Dosing and Administration Overview

Standard Dosing Regimen

Sarclisa is administered as an intravenous infusion at a dose of 10 mg/kg of actual body weight. The treatment follows a 28-day cycle:

• Cycle 1 (Induction): Weekly administration on Days 1, 8, 15, and 22.
• Cycle 2 and Onwards (Maintenance): Administration every two weeks on Days 1 and 15.

Preparation and Dilution

The calculated volume of Sarclisa is withdrawn from the vials and diluted in a 250 mL infusion bag of either 0.9% Sodium Chloride Injection, USP or 5% Dextrose Injection, USP.

Dose Modifications for Infusion Reactions

Management of infusion-related reactions (IRRs) is critical. Dose reductions are not recommended, but the infusion rate should be modified as follows:

• Grade 1 or 2 IRR: Interrupt the infusion immediately and provide supportive care. Once symptoms resolve, the infusion can be resumed at half of the rate at which the reaction occurred. If the patient tolerates it, the rate can be escalated according to the standard protocol.
• Grade 3 or 4 IRR: Permanently discontinue Sarclisa treatment.

Missed Dose Guidance

If a planned dose of Sarclisa is missed, it should be administered as soon as possible. The treatment schedule should then be adjusted accordingly to maintain the prescribed interval between doses.

Important Safety Alerts

Required Premedications

To reduce the risk and severity of IRRs, all patients must receive premedication 30 to 60 minutes prior to each Sarclisa infusion. This includes a corticosteroid (e.g., dexamethasone), an H1 antagonist (e.g., diphenhydramine), an H2 antagonist (e.g., famotidine), and an antipyretic (e.g., acetaminophen).

Neutropenia

Sarclisa can cause severe neutropenia. Monitor complete blood counts periodically during treatment. Consider the use of colony-stimulating factors and manage infections as per institutional guidelines.

Frequently Asked Questions

Dosing & Calculation

1. How does the calculator determine the optimal vial combination?
The algorithm prioritizes using the larger 500 mg vials first to meet the total dose, then uses 100 mg vials to cover the remainder, ensuring minimal drug wastage.

2. What happens if the patient's weight changes during treatment?
The dose should be recalculated based on the patient's current weight before each infusion to ensure accurate 10 mg/kg dosing.

3. Why is the infusion protocol different for the first few doses?
The first infusion starts at the slowest rate (50 mL/hr) and gradually increases. The second infusion uses a slightly faster protocol. This escalation strategy is designed to minimize the risk and severity of infusion-related reactions, which are most common during the initial doses.

4. Is there a maximum dose or weight cap for Sarclisa?
The prescribing information does not specify a maximum dose or weight cap. Dosing is based on the patient's actual body weight at 10 mg/kg.

Administration & Safety

5. Can the total infusion volume be changed from 250 mL?
No, the standard total infusion volume is 250 mL. This volume ensures the final drug concentration remains within the specified range for safe administration.

6. What diluents are compatible with Sarclisa?
Sarclisa should be diluted with either 0.9% Sodium Chloride Injection, USP or 5% Dextrose Injection, USP.

7. How long is the prepared infusion bag stable?
The diluted solution can be stored for up to 48 hours under refrigeration (2°C to 8°C), followed by a maximum of 8 hours at room temperature (including the total infusion time). It must be protected from light.

8. What are the most common adverse reactions?
The most common adverse reactions include neutropenia and infusion-related reactions. Other common reactions include pneumonia, upper respiratory tract infection, and diarrhea.

References

This information is based on established clinical guidelines and official prescribing information. For complete details, consult the primary sources.

1. SARCLISA® (isatuximab-irfc) injection, for intravenous use. U.S. Prescribing Information. Sanofi-aventis U.S. LLC. Revised: 07/2021. Accessed via FDA.gov.
2. Sarclisa (isatuximab) European public assessment report (EPAR). European Medicines Agency.
3. Sarclisa Official HCP Website. Sanofi Medical Information.
4. Moreau P, Dimopoulos MA, Yong K, et al. Isatuximab plus pomalidomide and dexamethasone in refractory multiple myeloma (ICARIA-MM). N Engl J Med. 2019;380(26):2519-2529.