Pronunciation: re-AB-nee
Generic name: rituximab-arrx
Dosage form: injection for intravenous infusion (100 mg/10 mL, 500 mg/50 mL)
Drug class: CD20 monoclonal antibodies

Medically reviewed by Carmen Pope, BPharm. Last updated on May 2, 2025.

What is Riabni?

Riabni is a biosimilar of Rituxan approved to treat:

• Non-Hodgkin's lymphoma in adults alone or with other chemotherapy medicines

• Chronic lymphocytic leukemia in adults, in combination with the chemotherapy medicines fludarabine and cyclophosphamide

• Rheumatoid arthritis (RA) in adults, in combination with methotrexate, to reduce signs and symptoms of moderate to severely active RA after an inadequate response to treatment with a Tumor Necrosis Factor (TNF) antagonist

• Granulomatosis with Polyangiitis (GPA, Wegener's granulomatosis) and Microscopic Polyangiitis (MPA) in adults, in combination with glucocorticoids.

Riabni (rituximab-arrx) gained FDA approval on December 17, 2020, and was the third biosimilar of Rituxan to be approved.

• Riabni is not approved for use in children or for pemphigus vulgaris.

Side effects

The most common side effects of Riabni are:

• infusion-related reactions
• infections (may include fever, chills)
• body aches
• tiredness
• nausea.

In adults with GPA or MPA, the most common side effects of Riabni also include:

• low white and red blood cells
• swelling
• diarrhea
• muscle spasms.

Other side effects of Riabni are:

• aching joints during or within hours of receiving an infusion
• more frequent upper respiratory tract infections.

Serious side effects and warnings

Riabni carries a Boxed Warning for fatal infusion-related reactions, severe skin reactions, hepatitis B virus reactivation, and a rare brain condition called progressive multifocal leukoencephalopathy (PML).

Riabni can cause the following serious side effects:

• Infusion-related reactions. These are very common side effects of Riabni treatment. Serious infusion-related reactions can happen during your infusion or within 24 hours after. Your healthcare provider should give you medicines before your Riabni infusion to decrease the chance of having a severe infusion-related reaction. Tell your healthcare provider or get medical help right away if you get any of these symptoms during or after an infusion:
  • hives (red itchy welts) or rash
  • shortness of breath, difficulty breathing, or wheezing
  • itching
  • weakness
  • swelling of your lips, tongue, throat, or face
  • dizziness or feeling faint
  • sudden cough
  • palpitations (feel like your heart is racing or fluttering)
  • chest pain.
• Severe skin and mouth reactions. Tell your healthcare provider or get medical help right away if you get any of these symptoms at any time during your treatment with Riabni:
  • painful sores or ulcers on your skin, lips, or in your mouth
  • blisters
  • peeling skin
  • rash
  • pustules.
• Hepatitis B virus (HBV) reactivation. Before you receive Riabni treatment, your healthcare provider will do blood tests to check for HBV infection. If you have had hepatitis B or are a carrier of the hepatitis B virus, receiving Riabni could cause the virus to become an active infection again. Hepatitis B reactivation may cause serious liver problems, including liver failure and death. You should not receive Riabni if you have active hepatitis B liver disease. Your healthcare provider will monitor you for hepatitis B infection during and for several months after you stop receiving Riabni. Tell your healthcare provider immediately if you get worsening tiredness or yellowing of your skin or white part of your eyes, during treatment.
• Progressive Multifocal Leukoencephalopathy (PML). PML is a rare, serious brain infection caused by a virus that can happen in people who receive Riabni. People with weakened immune systems can get PML. PML can result in death or severe disability. There is no known treatment, prevention, or cure for PML. Tell your healthcare provider right away if you have any new or worsening symptoms or if anyone close to you notices these symptoms:
  • confusion
  • dizziness or loss of balance
  • decreased strength or weakness on one side of your body
  • difficulty walking or talking
  • vision problems.
• Tumor Lysis Syndrome (TLS). TLS is caused by the fast breakdown of cancer cells. TLS can cause you to have:
  • kidney failure and need dialysis treatment
  • an abnormal heart rhythm.

TLS can happen within 12 to 24 hours after an infusion of Riabni. Your healthcare provider may do blood tests to check you for TLS. Your healthcare provider may give you medicine to help prevent TLS. Tell your healthcare provider right away if you have any of the following signs or symptoms of TLS:

• • nausea
  • diarrhea
  • vomiting
  • lack of energy.
• Serious infections. Serious infections can happen during and after treatment with Riabni and can lead to death. Riabni can increase your risk of getting infections and can lower the ability of your immune system to fight infections. Types of serious infections that can happen with Riabni include bacterial, fungal, and viral infections. After receiving Riabni, some people have developed low levels of certain antibodies in their blood for a long period (longer than 11 months). Some of these people with low antibody levels developed infections. People with serious infections should not receive Riabni. Tell your healthcare provider right away if you have any symptoms of infection:
  • fever
  • cold symptoms, such as a runny nose or sore throat, that do not go away
  • flu symptoms, such as cough, tiredness, and body aches
  • earache or headache
  • pain during urination
  • cold sores in the mouth or throat
  • cuts, scrapes, or incisions that are red, warm, swollen, or painful.
• Heart problems. Riabni may cause chest pain, irregular heartbeats, and a heart attack. Your healthcare provider may monitor your heart during and after treatment with Riabni if you have symptoms or heart problems or have a history of heart problems. Tell your healthcare provider right away if you have chest pain or irregular heartbeats during treatment with Riabni.
• Kidney problems, especially if you are receiving Riabni for NHL. Riabni can cause severe kidney problems that can lead to death. Your healthcare provider should do blood tests to check how well your kidneys are working.
• Stomach and serious bowel problems that can sometimes lead to death. Bowel problems, including blockage or tears in the bowel, can happen if you receive Riabni with chemotherapy medicines. Tell your healthcare provider right away if you have any severe stomach-area (abdomen) pain or repeated vomiting during treatment with Riabni.

Your healthcare provider will stop treatment with Riabni if you have severe, serious, or life-threatening side effects.

Get emergency medical help if you have signs of an allergic reaction to Riabni, such as hives, difficulty breathing, swelling in your face or throat, or a severe skin reaction (symptoms may include fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

These are not all of the possible side effects of Riabni. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088

Related/similar drugs

Before taking this medicine

Before you receive Riabni, tell your healthcare provider about all of your medical conditions, including if you:

• have had a severe reaction to Riabni or a rituximab product
• have a history of heart problems, irregular heartbeat, or chest pain
• have lung, liver, or kidney problems
• have an infection or a weakened immune system
• have or have had any severe infections, including:
  • Hepatitis B virus (HBV)
  • Parvovirus B19
  • Hepatitis C virus (HCV)
  • Varicella zoster virus (chickenpox or shingles)
  • Cytomegalovirus (CMV)
  • West Nile Virus
  • Herpes simplex virus (HSV).
• have had a recent vaccination or are scheduled to receive vaccinations. You should not receive certain vaccines before or during treatment with Riabni. You should be up-to-date on any needed immunizations before starting treatment with Riabni.
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

Riabni may harm an unborn baby. Talk to your healthcare provider about the risks to an unborn baby if you or someone you are caring for receives Riabni during pregnancy. If you are a female who can become pregnant, your healthcare provider should do a pregnancy test to check for pregnancy before starting Riabni.

Effective birth control (contraception) should be used during treatment with Riabni and for 12 months after the last dose. Talk to your healthcare provider about effective birth control.

Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with Riabni.

Breastfeeding

Riabni may pass into your breast milk. It is not safe to breastfeed a baby while you are using this medicine. Do not breastfeed during treatment and for 6 months after your last dose of Riabni.

How is Riabni given?

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using Riabni.

Riabni is given as an infusion into a vein. A healthcare provider will give you this injection.

Riabni is not given daily. Your schedule will depend on the condition being treated. Follow your doctor's dosing instructions very carefully.

Before each injection, you may be given other medications to prevent certain side effects of rituximab.

You will need frequent medical tests.

If you've ever had hepatitis B, using Riabni can cause this virus to become active or get worse. You may need frequent liver function tests while using this medicine and for several months after you stop.

If you need surgery, tell the surgeon ahead of time that you are using Riabni.

What happens if I miss a dose?

Call your doctor if you miss an appointment for your Riabni.

What happens if I overdose?

Since this medication is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving Riabni?

Do not receive a "live" vaccine while using Riabni. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

What other drugs will affect Riabni?

Tell your doctor about all your other medicines, especially:

• medicines to treat conditions such as rheumatoid arthritis, Crohn's disease, ulcerative colitis, or psoriasis--adalimumab, certolizumab, etanercept, golimumab, infliximab, leflunomide, methotrexate, sulfasalazine, tocilizumab, tofacitinib, and others.

This list is not complete. Other drugs may affect Riabni, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Ingredients

Active ingredient: rituximab-arrx

Inactive ingredients: polysorbate 80, sodium chloride, sodium citrate dihydrate, and Water for Injection, USP.
Hydrochloric acid is used to adjust the buffer solution pH.

Manufacturer

Riabni is manufactured by Amgen, Inc., One Amgen Center Drive, Thousand Oaks, CA.

Riabni Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Riabni.

Rituxan biosimilar products

Biosimilar products can only be dispensed in place of the reference product if the healthcare provider specifically prescribes the biosimilar product by name.

Pharmacy laws for biosimilar prescribing may vary by state

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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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