Pronunciation: lun-SUM-mee-oh
Generic name: mosunetuzumab
Dosage form: injection, for intravenous infusion
Drug class: Bispecific T-cell engagers (BiTE)

Medically reviewed by Melisa Puckey, BPharm. Last updated on Feb 27, 2025.

What is Lunsumio?

Lunsumio (mosunetuzumab-axgb) is used to treat relapsed or refractory follicular lymphoma (FL) in certain adults. Lunsumio is a bispecific antibody that targets CD20 on the surface of B cells and CD3 on the surface of T cells. Lunsumio works by activating your immune system (T cells) to target and fight cancerous B cells. Follicular lymphoma is the most common slow-growing form of non-Hodgkin’s lymphoma (NHL), affecting the lymphatic system.

Your healthcare provider gives Lunsumio as an IV infusion into a vein. 

Lunsumio's FDA approval indication is for the treatment of adult patients with: 

• relapsed or refractory follicular lymphoma (R/R FL) after 
• two or more lines of systemic therapy.

Lunsumio FDA approval was granted to Genentech, Inc. after positive results from the Lunsumio clinical trial Phase II GO29781. FDA approval was granted under the accelerated approval program, and continued approval will depend on confirmation of clinical benefit in the further trial(s).

How well does Lunsumio work?

Lunsumio success rate in Phase II GO29781 clinical trial:

• Overall Response Rate (ORR): 76.6% of patients responded to treatment.
• Complete Response Rate (CRR): 61.7% of patients achieved complete remission.
• Median progression-free survival (PFS): 23.7 months, indicating prolonged treatment effectiveness.
• Median overall survival was not reached at the time of analysis, showing sustained disease control.

How does Lunsumio work?

Lunsumio (mosunetuzumab-axgb) is a Bispecific T-cell engagers (BiTE).

Lunsumio's mechanism of action is as a bispecific antibody that binds to CD20 expressed on the surface of lymphoma cells and some healthy B-lineage cells and also binds to the CD3 receptor expressed on the surface of T-cells. This engages the body's immune system to target and kill malignant B cells. Lunsumio (mosunetuzumab-axgb) is a bispecific monoclonal antibody 

Mechanism of Action

Lunsumio operates by simultaneously binding to two specific proteins:

• CD20: A protein expressed on the surface of B cells, including malignant ones.
• CD3: A component of the T-cell receptor complex found on T cells, which are crucial for immune response.

By binding to B cells and T cells, Lunsumio brings these cells close together, activating the T cell to destroy the target B cell. This mechanism not only targets cancerous B cells but may also affect normal B cells with CD20 proteins.

Lunsumio side effects

Common side effects

Common Lunsumio side effects may include:

• Cytokine release syndrome (44%)
• Tiredness (42%)
• Rash (39%)
• Headache (32%)
• Fever (29%)
• Muscle and joint pain (28%)
• Cough (22%)
• Itching (21%)
• Peripheral neuropathy (20%)
• Edema (17%)
• Diarrhea (17%)
• Nausea (17%)
• Dry skin (16%)
• Abnormal lab results

These common side effects occurred in 15% or more of patients in the clinical trial GO2978.

Serious Lunsumio side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficulty breathing; swelling of your face, lips, tongue, or throat.

Tell your medical caregivers if you have signs of cytokine release syndrome (CRS), a serious side effect: fever, chills, trouble breathing, confusion, severe vomiting or diarrhea, fast or irregular heartbeats, feeling light-headed or very tired.

Lunsumio may cause serious side effects. Call your doctor at once if you have:

• signs and symptoms of nervous system disorders--headache; numbness or tingling in arms, legs, hands, or feet; dizziness, confusion, or disorientation; problems with balance, coordination, or muscle movement; sleepiness or sleeping problems; amnesia or forgetfulness; trouble speaking, writing, or reading; or seizures;
• low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;
• signs or symptoms of tumor related problems--chest pain, cough, breathing problems, tender or swollen lymph nodes, pain or swelling at tumor site; or
• signs of infection--fever, chills, sore throat, body aches, unusual tiredness, loss of appetite, bruising or bleeding.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

Tell your medical caregivers if you have symptoms of a serious side effect, such as fever, chills, trouble breathing, vomiting, or severe tiredness.

Call your doctor if you have signs and symptoms of neurological problems such as headache, dizziness, tremors, problems walking, confusion and disorientation, muscle problems or weakness.

Also call your doctor if you have signs of infection such as fever, chills, sore throat, body aches, unusual tiredness, loss of appetite, bruising or bleeding

Before taking this medicine

Tell your doctor if you have or have ever had:

• an infusion reaction after receiving mosunetuzumab;
• an infection or an infection that lasts a long time or keeps returning; or
• Epstein-Barr Virus (mononucleosis).

Pregnancy

This medicine may harm an unborn baby. Do not use if you are pregnant. Tell your doctor if you become pregnant.

You may need to have a negative pregnancy test before starting this treatment. Use effective birth control while using mosunetuzumab and for at least 3 months after your last dose. Do not breastfeed while using mosunetuzumab, and for at least 3 months after your last dose.

Breastfeeding

Tell your healthcare provider if you are breastfeeding or plan to breastfeed, as is not known if LUNSUMIO passes into your breast milk. Do not breastfeed during treatment and for 3 months after the last dose of this medicine.

How is Lunsumio given?

Follow all directions on your prescription label and read all medication guides or instruction sheets.

Lunsumiois given by a healthcare provider as an infusion into your vein. Your doctor will decide how many treatment cycles you will receive of this medicine.

You may be given other medications to help reduce your risk of cytokine release syndrome (CRS). Keep taking these medicines for as long as your doctor has prescribed.

Your healthcare provider will check for CRS while you are being treated with Lunsumio and may treat you in a hospital if you develop signs and symptoms of CRS.

Your treatment may be temporarily or permanently discontinued if you have certain side effects.

You will need medical tests.

Lunsumio dosing information

Usual Adult Dose for Follicular Lymphoma:

Cycle one
Day 1: IV infusion of 1mg once over at least 4 hours
Day 8: IV infusion of 2mg once over at least 4 hours
Day 15: IV infusion of 60mg once over at least 4 hours

Cycle two
Day 1: IV infusion of 60mg once over at least 2 hours if infusions from Cycle 1 were well-tolerated

Cycle three onwards
Day 1: IV infusion of 30mg once over at least 2 hours if infusions from Cycle 1 were well-tolerated

Duration of therapy:
Treatment duration based on complete or partial response unless unacceptable toxicity or disease progression occurs:

• Patients with complete response: 8 cycles
  
  
• Patients with partial response: 17 cycles total (8 initial cycles + 9 more cycles)
  
  

General dosing information

• Premedicate before each dose during Cycle 1 and Cycle 2; ensure adequate hydration prior to administering this drug.
• Do not use an in-line filter to administer this drug.
  
  
• Patients who achieved a partial response or stable disease after 8 cycles of treatment with this drug are eligible for an additional 9 cycles of treatment (17 cycles total) unless they experience unacceptable toxicity or disease progression.
  
  
• Refer to the manufacturer's prescribing information for premedication and recommendations for restarting therapy with this drug after a dose delay.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your mosunetuzumab injection.

What happens if I overdose?

In a medical setting, an overdose would be treated quickly.

What other drugs will affect this medicine?

Other drugs may affect mosunetuzumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Lunsumio J code 

Lunsumio J code J9350 (1 mg, injection)
J codes are used for medicines that are not taken orally and include injections, inhalations, and chemotherapies. J codes is a medical billing code that is important for accurate and consistent coding for billing and reimbursement purposes.

Your physician will need the Lunsumio J-code when filling out forms for your treatment.

Lunsumio Package Insert 

HCPs and patients can refer to the Lunsumio Package Insert (PI) for more detailed information about this medicine. The Lunsumio Package Insert contains more comprehensive information on Indications and Usage, Dosage and Administration, Clinical Pharmacology, Clinical Studies, Drug Interaction, and more. Discuss any medical questions you have with your HCP (health care professional). This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

The Package Insert is sometimes called Lunsumio FDA label or the Prescribing Information (PI).

What should I avoid while receiving this medicine?

Do not drive, operate heavy machinery, or do other dangerous activities if you develop dizziness, confusion, tremors, sleepiness, or any other symptoms that impair consciousness until your signs and symptoms go away. These may be signs and symptoms of CRS or neurologic problems.

Ingredients

Active ingredient: mosunetuzumab-axgb
Inactive ingredients: acetic acid, histidine, methionine, polysorbate 20, sucrose, and Water for Injection

Company

Lunsumio Genentech, Inc., A Member of the Roche Group, 1 DNA Way, South San Francisco, CA 94080-4990

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Further information

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

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