What has SMC said?

The Scottish Medicines Consortium (SMC) has accepted mercaptamine (Procysbi®) for use to treat patients with nephropathic (kidney) cystinosis. Cystinosis is an inherited condition, where an amino acid called cystine builds up in cells, especially the kidneys causing damage to them.

This document summarises the SMC decision and what it means for patients.

You can find more detailed information about the SMC assessment of mercaptamine by looking at the SMC Detailed Advice Document (SMC2824).

What does SMC’s decision mean for patients?

Mercaptamine (Procysbi®) for use as described above is available for prescribing on the NHS in Scotland. Your healthcare professional can discuss with you if it is the right treatment for you or your child.

You can find more information about making decisions about your treatment in this booklet called: Medicines in Scotland: What’s the right treatment for me?

More about SMC’s decision

SMC decision takes into account a confidential discount offered by the pharmaceutical company. SMC was also able to be more flexible in its decision-making because the medicine is for a rare condition.

How does SMC make its decision?

SMC carefully considers every new medicine to make sure it benefits patients and is likely to be a good use of NHS resources.

To do this SMC studies the following:

  • Evidence from the company about how well the medicine works compared with current treatments available in Scotland, in relation to how much they will cost to buy and use to treat patients.
  • Information from patient groups about the potential impact of the medicine on patients and carers.
  • Advice from healthcare professionals about any benefits of the new medicine compared to current treatment, along with how the new medicine is likely to be used.

When SMC assesses a medicine it takes account of the needs of all patients in NHSScotland, not only those who may be treated with the medicine.

You can find out more about how SMC decides here: https://www.scottishmedicines.org.uk/how-we-decide/

More information and support

The organisations below can provide more information and support for people living with nephropathic cystinosis and their families. SMC is not responsible for the content of any information provided by external organisations.

Cystinosis Foundation
https://www.cystinosis.org.uk            

Kidney Research UK
https://www.kidneyresearchuk.org

Metabolic Support UK
https://metabolicsupportuk.org
0800 652 3181                          

You can find out more about mercaptamine (brand name: Procysbi®) in the Patient Information Leaflet (PIL) by searching for the medicine name on the Medicines and Healthcare products Regulatory Agency (MHRA) website https://products.mhra.gov.uk/          

Date advice published: 10 November 2025
SMC ID: SMC2824