Glofitamab Dosage

Medically reviewed by Drugs.com. Last updated on Oct 23, 2023.

Usual Adult Dose for B-Cell Lymphoma

Recommended dosing schedule:
Pretreat all patients with obinutuzumab before initiating therapy.

Cycle 1:

• Day 1 of treatment (pretreatment with obinutuzumab): Obinutuzumab 1000 mg intravenously at 50 mg/hour. The rate of infusion can be escalated in 50 mg/hour increments every 30 minutes, to a maximum of 400 mg/hour.
• Day 8 of treatment (step-up dose 1): 2.5 mg intravenously over 4 hours
• Day 15 of treatment (step-up dose 2): 10 mg intravenously over 4 hours

Cycle 2:

• Days 1 of treatment: 30 mg intravenously over 4 hours

Cycle 3 to 12:

• Days 1 of treatment: 30 mg intravenously over 2 hours

Restarting schedule after dosage delay:

• If the last dose administered was obinutuzumab pretreatment on Cycle 1, Day 1:
• Two weeks or less since the last dose: Administer glofitamab 2.5 mg, then resume the planned treatment schedule.
• Greater than 2 weeks: Repeat obinutuzumab 1000 mg pretreatment and resume the planned glofitamab treatment schedule.

• If the last dose administered was 2.5 mg on Cycle 1, Day 8:
• Two weeks or less since the last dose: Administer 10 mg then resume the planned treatment schedule.
• Greater than 2 weeks but 4 weeks or less since the last dose: Repeat 2.5 mg, then administer 10 mg and resume the planned treatment schedule.
• Greater than 4 weeks since the last dose: Repeat obinutuzumab 1000 mg pretreatment and 2.5 mg dose then administer 10 mg and resume the planned treatment schedule.

• If the last dose administered was 10 mg on Cycle 1, Day 15:
• Two weeks or less since the last dose: Administer 30 mg then resume the planned treatment schedule.
• Greater than 2 weeks but 6 weeks or less since the last dose: Repeat 10 mg, then administer 30 mg and resume the planned treatment schedule.
• Greater than 6 weeks since the last dose: Repeat obinutuzumab 1000 mg pretreatment, 2.5 mg and 10 mg doses then administer 30 mg dose and resume the planned treatment schedule.

• If the last dose administered was 30 mg on Cycle 2 onwards and 6 weeks or less since the last dose:
• Repeat the Cycle 1 regimen, then administer 30 mg (Day 1 of next cycle) and resume the planned treatment schedule.

Recommended Premedications:
Cycle 1 (Days 8 and 15), Cycles 2 and 3 (all patients require premedication):

• Dexamethasone 20 mg intravenously, completed at least 1 hour prior to treatment. If dexamethasone is unavailable, administer prednisone 100 mg, prednisolone 100 mg, or methylprednisolone 80 mg intravenously.
• Acetaminophen 500 mg to 1000 mg orally, at least 30 minutes prior to treatment.
• Diphenhydramine 50 mg oral or intravenous or equivalent, completed at least 30 minutes prior to treatment

All subsequent infusions:

• All patients:
• Acetaminophen 500 mg to 1000 mg orally, at least 30 minutes prior to treatment.
• Diphenhydramine 50 mg oral or intravenous or equivalent, completed at least 30 minutes prior to treatment

• Patients who experienced cytokine release syndrome (CRS) with the previous dose:
• Dexamethasone 20 mg intravenously, completed at least 1 hour prior to treatment. If dexamethasone is unavailable, administer prednisone 100 mg, prednisolone 100 mg, or methylprednisolone 80 mg intravenously.

Comments:

• Refer to obinutuzumab prescribing information for complete dosing information.
• Duration of infusion for this drug should be doubled for patients who experience cytokine release syndrome (CRS).
• Administer for a maximum of 12 cycles until disease progression or unacceptable toxicity.

Uses: For the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), or large B-cell lymphoma (LBCL) arising from follicular lymphoma, after two or more lines of systemic therapy.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

See manufacturer prescribing information for the management of CRS and neurologic toxicity, including ICANS.

Recommended dose adjustments for other adverse reactions:

• Infections (Grades 1-4): Withhold therapy in patients with active infections until resolved. For Grade 4, consider permanent discontinuation of therapy.
• Tumor flare: For grade 1, monitor for signs and symptoms of compression or obstruction due to mass effect secondary to tumor flare. For grades 2 to 4, monitor for signs and symptoms of compression or obstruction due to mass effect secondary to tumor flare, and administer appropriate treatment including antihistamine and corticosteroid. Withhold treatment regimen until tumor flare resolves.
• Neutropenia (absolute neutrophil count less than 0.5 x 10(9)/L): Withhold therapy until the absolute neutrophil count is 0.5 x 10(9)/L or higher.
• Thrombocytopenia (platelet count less than 50 x 10(9)/L): Withhold therapy until platelet count is 50 x 10(9)/L or higher.
• Other Adverse Reactions (Grade 3 or higher): Withhold therapy until the toxicity resolves to grade 1 or baseline.

Precautions

US BOXED WARNING:

• CYTOKINE RELEASE SYNDROME (CRS): CRS, including serious or fatal reactions, can occur in patients receiving this drug. Premedicate before each dose, and initiate treatment using the step-up dosing schedule to reduce the risk of CRS. Withhold therapy until CRS resolves or permanently discontinue based on severity.

CONTRAINDICATIONS: None

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:

• For intravenous use only.
• Administer to well-hydrated patients.
• Should be administered by a healthcare professional with immediate access to appropriate medical support, including management of severe cytokine release syndrome (CRS).
• Patients should be hospitalized during treatment and for 24 hours after completion of step-up dose 1 therapy.
• Administer premedication and prophylaxis as recommended.

Storage requirements:

• Refrigerate at 2C to 8C (36F to 46F). Do not freeze.
• Keep in the original carton to protect from light.
• Do not shake.

Reconstitution/preparation techniques:

• The manufacturer's product information should be consulted for detailed dilution and preparation instructions.

Patient advice:

• Read Patient Information Leaflet.
• Advise females of reproductive potential of the potential risk to the fetus and to use effective contraception during treatment and for 1 month after the last dose. Advise them to inform their healthcare professional if they are pregnant or become pregnant while in treatment.
• Breastfeeding is not recommended during treatment with this drug and for 1 month after the last dose.
• Signs and symptoms associated with infections should be reported.

Further information

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

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