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Important information about your medicine – rituximab biosimilar switch

This webpage is for patients who are currently prescribed or have been prescribed a medicine called rituximab in the past, under the care of King’s College Hospital NHS Foundation Trust.

If you are no longer prescribed this medication, please disregard the following.

From April 2026, we will be changing the brand of this medicine from Rixathon to Truxima. Both Rixathon and Truxima are known as biosimilar medicines. This webpage provides more information about this change and what this means for you.

What is a biosimilar medicine?

A biosimilar is a highly similar version of an existing biological medicine (called an originator medicine or reference product). It is approved by the Medicines and Healthcare products Regulatory Agency (MHRA). Biosimilars match the originator medicine in terms of safety, quality, and effectiveness and have been widely used in the NHS for many years.

Why is this change happening?

This change is part of national and Trust-wide efforts to optimise the use of best value medicines. All medicines made by pharmaceutical companies have a patent that lasts a number of years. The patent means that only the company who developed the medicine is allowed to sell it. When patents expire, more pharmaceutical companies can manufacture and licence the medicine so there is more competition, which lowers the cost of the medication.

Cost savings can be substantial and by switching to the biosimilar we are able to provide you with the same level of care whilst saving money that can be redirected to patient care within the NHS. This means that your biosimilar brand may be switched again in the future and this will be communicated with you in clinic. We have a lot of experience with switches at King’s College Hospital NHS Foundation Trust across multiple specialties.

Am I likely to experience side effects after switching?

As you have been on Rixathon previously, you are unlikely to experience any new or different side effects after switching to a different biosimilar medicine. As always, your treatment will continue to be carefully monitored. If you do experience any side effects or have concerns, please contact your doctor or specialist nurse.

Do I need any additional tests before switching?

No additional tests are required specifically for the switch. You will continue to have routine blood test monitoring as advised by your clinical team.

What does this mean for you?

  • You may notice a different brand name or delivery device (e.g., pre-filled pen or syringe) being used by your healthcare professional, but this does not affect how the medicine works.
  • You will continue to receive the same level of care and clinical monitoring.
  • The way the medicine works in your body will remain the same.

Further information and support

If you have questions or concerns regarding the switch, please contact us by phone or email using the details below and a member of the pharmacy team will phone you back at a suitable time.

Please provide the following details in your email or message:

  • full name
  • NHS or MRN number
  • date of birth
  • contact number
  • the name of the department that prescribes this medication for you
  • availability for a call back between 10am and 4pm, Monday to Friday

Please note this is a dedicated phone number and email address for biosimilar switches which will be open for a limited time between 6 April 2026 and 20 April 2026. Outside of this time please contact your prescribing team via your regular clinic.

We encourage all patients to sign up for the MyChart app to receive reminders for appointments and monitoring.

For further information, go to:

The Patients Association website – information on switching to biosimilar medicines

We are here to support you throughout this transition. Thank you for your continued cooperation.