In how much normal saline (0.9% NaCl) should the reconstituted enfortumab‑vedotin be diluted?

Enfortumab Vedotin Dilution in Normal Saline

Dilute the reconstituted enfortumab vedotin to achieve a final concentration of 0.3 mg/mL to 4 mg/mL in an infusion bag containing 5% Dextrose Injection, 0.9% Sodium Chloride Injection, or Lactated Ringer's Injection 1.

Preparation Algorithm

Step 1: Reconstitution

• 20 mg vial: Add 2.3 mL Sterile Water for Injection → yields 10 mg/mL
• 30 mg vial: Add 3.3 mL Sterile Water for Injection → yields 10 mg/mL
• Swirl gently until dissolved; do NOT shake 1

Step 2: Dilution Volume Calculation

After reconstitution, the infusion bag size must be selected to allow sufficient diluent to achieve the target concentration range of 0.3-4 mg/mL 1.

To determine the appropriate bag size:

• Calculate total dose based on patient weight (1.25 mg/kg, maximum 125 mg)
• Minimum bag volume = Total dose (mg) ÷ 4 mg/mL
• Maximum bag volume = Total dose (mg) ÷ 0.3 mg/mL

Example: For a 100 mg dose:

• Minimum volume: 100 mg ÷ 4 mg/mL = 25 mL
• Maximum volume: 100 mg ÷ 0.3 mg/mL = 333 mL
• Therefore, use a bag size between 25-333 mL (typically 50-250 mL bags are practical)

Step 3: Diluent Selection

Choose one of the following 1:

• 0.9% Sodium Chloride Injection (Normal Saline)
• 5% Dextrose Injection
• Lactated Ringer's Injection

Step 4: Administration

• Infuse over 30 minutes through IV line 1
• Do NOT administer as IV push or bolus
• Do NOT mix with other medications 1

Critical Timing Considerations

Reconstituted vials:

• Use immediately, or
• Store up to 24 hours at 2°C-8°C (36°F-46°F) 1

Prepared infusion bag:

• Administer immediately, or
• Store maximum 8 hours at 2°C-8°C (36°F-46°F) 1
• Do NOT freeze 1

Key Safety Points

The concentration range of 0.3-4 mg/mL provides flexibility based on patient-specific dosing needs while maintaining drug stability. The specific volume of normal saline depends on the calculated patient dose and desired final concentration within this range—there is no single fixed volume applicable to all patients 1.

This preparation method applies whether enfortumab vedotin is used as monotherapy or in combination with pembrolizumab, as pharmacokinetics remain consistent across both regimens 1.