Patient Advocacy Statement on the Forced Switch from Tysabri IV to Tyruko 

By Mrs Julie Cowdrill – Founder of the 'Reinstate Tysabri IV' Petition (38,000+ Signatures) 

Requesting for the reinstatement of Tysabri IV.

I am still fighting — not just for myself, but for every MS patient across the UK who has been thriving on Tysabri IV for years and now finds themselves deteriorating after being switched to Tyruko, its biosimilar. 

Is it not devastating enough that we are living with this chronic illness? To have our lifeline (Tysabri IV) ripped away from us? Then with what little energy we have, ultimately, having to fight to have it reinstated. 

This Is About more Than Medication — It's About Lives 

The forced switch from Tysabri (Natalizumab), a gold-standard DMT, to the cheaper biosimilar Tyruko has left many of us in crisis. I have now gathered 103 co-signatures from patients at 31 different hospitals — all sharing the same story: since switching, symptoms that had been dormant for years are reawakening. People are relapsing, losing mobility, and losing hope. 

Tyruko Trial Data: Alarmingly Thin 

The trial data for Tyruko does not reflect the real-world, long-term stability that so many patients had on Tysabri

Tysabri AFFIRM Trial: 942 patients over 2 years
Tyruko ANTELOPE Trial: 531 patients over just 48 weeks — only 30 (only 29 completed it)  had switched from Tysabri 
The "switch" group where treatment Naive when the trial was began. They were given Tysabri Iv for 24 weeks (6 infusions), and then swapped over to Tyruko for a further 24 weeks. This is not a sufficient study to represent patients being treated with Tysabri long term (many have been on Tysabri Iv for over a decade!).
Where is the long-term evidence that this switch is safe for patients with stable RRMS?

“In the NHS, disease-modifying therapies are used to treat RRMS. The aim of treatment is to reduce the number of relapses, slow progression of disability, and maintain or improve quality of life.” — NICE 

We are not anti-biosimilar. We are anti forced switching in complex diseases without safety nets or individualised care.

 Where Is the Disconnect?

 NHS England has told the MS Society that:
"Anyone who’s experienced an adverse event or deterioration on Tyruko should have the option to switch back to Tysabri IV, through a shared decision-making process with their clinician — regardless of where they are treated." 

(However we, including MS Society, have yet to see this statement mentioned anywhere on officially.).

Yet, many patients are being told that Tysabri IV is no longer an option. So the question is:

•  Are NHS England failing to communicate this to ICBs?
• Are ICBs failing to communicate this to hospital Trusts?
• Or is the system simply choosing not to act? 
• I want to be very clear: I do not believe hospital MS teams are to blame. But I am deeply disappointed that more of them are not actively advocating on behalf of patients they know are struggling. They are our first line of care — they know how well we were doing before, and how much we’ve regressed. 

Missed Oversight, Missed Opportunity 

There should have been:

Clear national monitoring of Tyruko rollout to previously stable Tysabri patients 
Formal guidance for clinicians on how to track and report patient decline - A reversal pathway clearly communicated to every Trust and ICB 
That this wasn’t done is a serious oversight, and somewhat negligent. And the consequences are being felt by thousands of us, every single day. 

Policy and Prescribing Authority: Additional Information 

Thanks to Lawrence Turner MP for Birmingham Northfield, the House of Commons Library has clarified who actually has authority over prescribing decisions, and what guidance is influencing the rollout of biosimilars like Tyruko. 

Key Points from House of Commons Library 

The decision to switch between biosimilar medicines lies with the prescriber, who should follow national or local guidance. 
NHS England promotes the uptake of biosimilars to save money — up to £1 billion — and aims for 80% adoption within 6–12 months. 

NHS guidance emphasises shared decision-making with patients and highlights the importance of considering clinical stability and product suitability. 

Birmingham and Solihull Integrated Medicines Optimisation Committee defers to NICE guidance on natalizumab, which recognises both Tysabri and Tyruko but does not comment on switching. 

Integrated Care Boards (ICBs) hold authority to develop local prescribing guidance and manage health service delivery. No local guidance for natalizumab switching has yet been published by Birmingham and Solihull ICB. 
NHS Specialist Pharmacy Service guidance on implementing natalizumab biosimilars notes that: 

Additional monitoring may be required post-switch.
Patient registries may help identify safety concerns with biosimilars. 
This information reinforces that prescribers — in collaboration with patients — retain the right to make decisions based on individual clinical need, and that there is no national mandate requiring forced switches from Tysabri to Tyruko. 
We Are Not Done Fighting 

We need the NHS to listen, to act, and to put patients first again. Our health — our lives — are not line items on a spreadsheet. 

If you’re a patient affected, write to your MS team. If you’re a clinician, raise your voice.
If you’re a policymaker, do your job.