Mosunetuzumab
Mosunetuzumab is a bispecific monoclonal antibody used to treat certain types of B-cell lymphoma, including follicular lymphoma and diffuse large B-cell lymphoma. It works by simultaneously binding to CD20 on cancer cells and CD3 on T-cells, bringing them together so the T-cells can destroy the cancer cells. This medication is typically used in patients who have received at least two prior lines of therapy.
Mosunetuzumab is a T-cell engaging bispecific antibody that targets CD20 on B-cell lymphomas and CD3 on T-cells to enable immune destruction of cancer cells.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L01FX25
- RxNorm
- 2625122
- Generic
- Mosunetuzumab
- Class
- atc-l01
- Brands
- Lunsumio
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- Cycle 1: 1mg on Day 1, 2mg on Day 8, 60mg on Day 15; Cycles 2-13: 60mg on Day 1
- Maximum
- consult physician
- Frequency
- Step-up dosing in Cycle 1, then every 21 days
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 60mg
- Maximum
- consult physician
- Frequency
- every 21 days for up to 17 cycles
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- Premedication with corticosteroid, antihistamine, and acetaminophen recommended
- Maximum
- consult physician
- Frequency
- prior to each dose
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
9 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks; discuss with healthcare provider
regular fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second third trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks; consider risks of placental transfer increasing in later pregnancy
regular fetal monitoring and ultrasound assessments
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingdiscontinue breastfeeding
discontinue breastfeeding during treatment and for at least 3 months after last dose due to unknown excretion in breast milk
monitor infant for adverse effects if breastfeeding continues
pediatric_age
children adolescentsnot recommended
safety and efficacy not established in pediatric patients; use only in clinical trials
not applicable - not studied in pediatric populations
geriatric
elderly 65 plusno specific dose adjustment required
use with caution; monitor for adverse reactions; no dose adjustment needed based on age alone
regular monitoring of adverse effects and cytokine release syndrome symptoms
Use with caution and monitor for adverse effects.
renal_impairment
mild moderateno dose adjustment required
no dose adjustment needed for mild to moderate renal impairment; monitor patients for adverse reactions
routine renal function monitoring
renal_impairment
severeuse with caution
limited data in severe renal impairment; use with caution and monitor closely
increased monitoring of renal function and adverse effects
Use with caution and monitor for adverse effects.
hepatic_impairment
mildno specific adjustment
no dose adjustment needed for mild hepatic impairment; use with caution
routine liver function monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
moderate severeinsufficient data
use with caution; limited clinical data available for moderate to severe hepatic impairment
close monitoring of liver function tests
Statistics and clinical data
FDA Approval Year
FDA approval for Mosunetuzumab (Lunsumio) for adult patients with follicular lymphoma who have received at least two prior systemic therapies
Drug class
Classification as bispecific monoclonal antibody therapy
Indication
Therapeutic indication for adult patients with relapsed or refractory follicular lymphoma
Mechanism of action
Bispecific T-cell engager (BiTE) mechanism
Mosunetuzumab is indicated for the treatment of adult patients with relapsed or refractory follicular lymphoma (FL) who have received at least two prior systemic therapies. It may also be used for other B-cell non-Hodgkin lymphomas based on clinical trial data and regulatory approvals.
Mosunetuzumab is a bispecific antibody that binds to two different targets: CD20, which is expressed on the surface of lymphoma cells and some healthy B-lineage cells, and CD3, a receptor on T-cells. This dual binding brings T-cells into close proximity with cancer cells, activating the T-cells to attack and destroy the malignant B-cells through cell-mediated cytotoxicity.
As a T-cell engaging therapy, mosunetuzumab can cause cytokine release syndrome (CRS), which may range from mild to severe. Other common side effects include fatigue, fever, and cytopenias. Due to its effect on healthy B-cells, patients may experience hypogammaglobulinemia and increased risk of infections. Administration requires careful monitoring, particularly during the first treatment cycle.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
WellAlly may earn a referral fee from linked resources at no extra cost to you. Editorial content is never influenced by commercial relationships.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy