Mosunetuzumab is used to treat follicular lymphoma (a cancer of the lymphatic system) in adults whose cancer has returned or did not respond to another treatment and who have received at least two previous cancer treatments.

Mosunetuzumab may also be used for purposes not listed in this medication guide.

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

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

Mosunetuzumab is 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 mosunetuzumab and may treat you in a hospital if you develop signs and symptoms of CRS.

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

You will need medical tests.

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)

Comments:
-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.

Use: For the treatment of adult patients with relapsed or refractory follicular lymphoma after two or more lines of systemic therapy

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).

You may need to have a negative pregnancy test before starting this treatment.

May harm an unborn baby. Do not use if you are pregnant. Use effective birth control while using mosunetuzumab and for at least 3 months after your last dose. Tell your doctor if you become pregnant.

Do not breastfeed while using mosunetuzumab, and for at least 3 months after your last dose.

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

In a medical setting an overdose would be treated quickly.

Avoid driving or hazardous activity until you know how mosunetuzumab will affect you. Your reactions could be impaired.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult 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.

Mosunetuzumab 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.

Common side effects of mosunetuzumab may include:

• abnormal lab results;

• tiredness;

• rash;

• fever; or

• headache.

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.

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.