Retifanlimab Dosage

Medically reviewed by Drugs.com. Last updated on Oct 9, 2023.

Usual Adult Dose for Merkel Cell Carcinoma

Dose: 500 mg IV every 4 weeks

• Administer as IV infusion over 30 minutes until disease progression, unacceptable toxicity, or up to 24 months

Comments:
This indication is approved under accelerated approval based on tumor response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials.

Use: For the treatment of adult patients with metastatic or recurrent locally advanced Merkel cell carcinoma (MCC)

Renal Dose Adjustments

• Estimated GFR greater than 26 mL/min/1.73 m2: No adjustment recommended
• Estimated GFR less than 26 mL/min/1.73 m2: Data not available

Liver Dose Adjustments

• Mild liver dysfunction (total bilirubin [TB] less than or equal to upper limit of normal [ULN] and AST greater than ULN, or TB greater than 1 to 1.5 x ULN and any AST): No adjustment recommended
• Moderate to severe liver dysfunction: Unknown

Dose Adjustments

General guidelines for dose adjustments for adverse reactions:

• Dose reductions are not recommended for this drug.
• If interruption or discontinuation is required, administer systemic corticosteroid therapy (1 to 2 mg/kg/day prednisone or equivalent) until improvement to Grade 1 or less; once at Grade 1 or less, a corticosteroid taper is initiated and continued over at least 1 month.
• Withhold this drug for severe (Grade 3) immune-mediated adverse reactions.
• Permanently discontinue this drug for recurrent (Grade 3) immune-mediated reactions that require systemic immunosuppressive treatment, or an inability to reduce corticosteroid dose to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• Permanently discontinue this drug for life-threatening (Grade 4) immune-mediated adverse reactions.

Dose adjustments for adverse reactions that require management different from general guidelines:
PNEUMONITIS:

• For Grade 2 immune-mediated pneumonitis: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce prednisone to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• For Grade 3 or 4: Permanently discontinue therapy

COLITIS:

• For Grade 2 or 3 immune-mediated colitis: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce prednisone to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• For Grade 4: Permanently discontinue therapy

HEPATITIS WITH NO TUMOR INVOLVEMENT OF THE LIVER:

• If AST or ALT increases greater than 3 and up to 8 times the upper limit of normal (8 x ULN) OR total bilirubin increases greater than 1.5 and up to 3 x ULN: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce prednisone to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• If AST or ALT increases to greater than 8 x ULN OR total bilirubin increases greater than 3 x ULN:

Permanently discontinue therapy

HEPATITIS WITH TUMOR INVOLVEMENT OF THE LIVER:

• If baseline AST or ALT less than or up to ULN: Withhold or permanently discontinue based on recommendations for hepatitis with no liver involvement.
• If baseline AST or ALT greater than 1 and up to 3 x ULN and increases greater than 5 and up to 10 x ULN, OR baseline AST or ALT greater than 3 and up to 5 x ULN and increases greater than 8 and up to 10 x ULN: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce prednisone to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• If AST or ALT increases to greater than 10 x ULN, OR total bilirubin increases greater than 3 x ULN: Permanently discontinue therapy

ENDOCRINOPATHIES:

• For Grade 2 immune-mediated endocrinopathies: Consider withholding depending on severity until symptom improvement with hormone replacement as clinically indicated; resume once acute symptoms resolved.
• For Grade 3 or 4 immune-mediated endocrinopathies: Withhold until clinically stable or permanently discontinue depending on severity.

NEPHRITIS WITH RENAL DYSFUNCTION:

• For Grade 2 or 3 increased blood creatinine: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• For Grade 4 increased blood creatinine: Permanently discontinue therapy

EXFOLIATIVE DERMATOLOGIC CONDITIONS:

• For Grade 3 or suspected SJS, TEN, or DRESS: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• For Grade 4 or confirmed SJS, TEN, or DRESS: Permanently discontinue therapy

MYOCARDITIS

• For Grade 2, 3, or 4 immune-mediated myocarditis: Permanently discontinue therapy

NEUROLOGICAL TOXICITIES:

• For Grade 2 immune-mediated neurological toxicities: Withhold; resume in patients with complete or partial resolution to Grade 0 or 1 after corticosteroid taper. Permanently discontinue if no resolution within 12 weeks of initiating steroids or inability to reduce to 10 mg/day or less of prednisone (or equivalent) within 12 weeks of initiating steroids.
• For Grade 3 or 4: Permanently discontinue therapy

INFUSION-RELATED REACTIONS

• For Grade 1 or 2: Interrupt or slow the rate of infusion
• For Grade 3 or 4: Permanently discontinue therapy

Precautions

CONTRAINDICATIONS: None

US FDA requires a medication guide to assure safe use. For additional information: www.fda.gov/drugs/drug-safety-and-availability/medication-guides

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• Review the manufacturer product information prior to administration.
• Administer as an IV infusion over 30 minutes; do not use a polyurethane infusion set.
• Do not administer as IV push or bolus injection.
• Consult manufacturer product information prior to administration.

Storage requirements:

• Protect from light.
• Do not freeze or shake.
• Store single-dose vials in refrigerator at 2C to 8C (36F to 46F) in the original carton.
• Store diluted solution at room temperature (up to 25C or 77F) for no more than 8 hours (inclusive of infusion time); may store refrigerated from 2C to 8C (36F to 46F) for no more than 24 hours from time to preparation to end of infusion.
• If refrigerated, allow diluted solution to come to room temperature and administer within 4 hours, including infusion time.

Reconstitution/preparation techniques:

• The manufacturer product information should be consulted prior to product preparation.
• Dilute prior to administration; dilute in 0.9% sodium chloride or 5% dextrose; mix solution by gentle inversion; do not shake.
• Final concentration should be between 1.4 mg/mL to 10 mg/mL

IV compatibility:

• Do not administer other drugs through the same infusion line.

Monitoring:

• Monitor for immune-mediated adverse reactions
• Obtain liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment
• Monitor for infusion reactions
• Monitor for hyperglycemia

Patient advice:

• Patients should be instructed to read the US FDA-approved patient labeling (Medication Guide).
• Patients should be informed of the risk of immune-mediated adverse reactions.
• Females of reproductive potential should be advised to use effective contraception during therapy and for 4 months after their last dose; do not breastfeed while taking this medication.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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