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Important information about your medicine – ranibizumab biosimilar switch

This webpage is for patients who are currently prescribed or have recently been prescribed a medicine called ranibizumab, under the care of our ophthalmology department.

It is about an upcoming change to your intravitreal injection (injection into the eye) treatment with ranibizumab at King’s College Hospital NHS Foundation Trust.

From February 2026, we will be changing the brand of this medicine from Ximluci to Rimmyrah.

Both brands are biosimilar medicines. This page 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). Biosimilars are approved by the Medicines and Healthcare products Regulatory Agency (MHRA) and match the originator medicine in terms of safety, quality, and effectiveness and have been widely used in the NHS for many years.

A biosimilar product is interchangeable with both the original biological medicine and another biosimilar. Switching from the original biological medicine to the biosimilar version or from one biosimilar to another biosimilar is routine clinical practice across the NHS.

Why is this change happening?

Ximluci is no longer being manufactured therefore we have sourced an alternative brand of ranibizumab (Rimmyrah). Due to the dynamic nature of healthcare, your biosimilar brand may be switched again in the future. We will tell you if your medicine is changing, either by an electronic letter on your MyChart app, a text message, an email, a physical letter in the post, or at the eye clinic. We have a lot of experience with switches across multiple specialties.

Am I likely to experience side effects after switching?

As you have been on Ximluci previously, you are unlikely to experience any new or different side effects after switching to the new 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 should continue with your routine monitoring, such as clinical examinations and scans of your eyes, as advised by your clinical team.

What does this mean for you?

  • You may notice a different brand name or delivery device (for example, 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
  • date of birth
  • contact number
  • availability for a call back between 10am and 4pm, Monday to Friday

Please note this is a dedicated phone number and email address for ophthalmology biosimilar switches which will be open for a limited time between 13 January 2026 and 27 Feb 2026. Outside of this time please contact your prescribing team via your eye clinic.

We encourage all patients to sign up to MyChart 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.