The Medicines and Healthcare products Regulatory Agency (MHRA) has approved Siiltibcy (rdESAT-6 and rCFP-10), a diagnostic aid for detection of Mycobacterium tuberculosis infection, including tuberculosis disease, in adults and children.
Tuberculosis (TB) is an infectious disease most commonly affecting the lungs, but capable of spreading to other parts of the body. It is usually transmitted through the air.
Siiltibcy is given as an injection in the skin of the forearm. It contains two active substances, rdESAT-6 and rCFP-10, which are proteins specific of Mycobacterium tuberculosis that have been produced in a laboratory.
If a person has been infected with Mycobacterium tuberculosis, her/his immune system will respond by producing cytokines (inflammatory proteins) which cause induration (hardening) at the site where SIILTIBCY was injected that usually occurs 48 to 72 hours after injection. The size of the induration will be measured to determine if the person is infected with M. tuberculosis or has tuberculosis.
Siiltibcy has been evaluated in 3 main studies involving over 2000 participants, including children.
The most common side effect was pruritus (itching) at the injection site, which affected more than 1 in 10 people. A full list of side effects can be found in the Patient Information Leaflet (PIL) or the Summary of Product Characteristics (SmPC), which will be available on the MHRA website within 7 days of approval.
As with all medicinal products, the MHRA will keep the safety and effectiveness of Siiltibcy under close review.
Anyone who suspects they are having a side effect from this product is encouraged to talk to their doctor, pharmacist, or nurse and report it directly to the MHRA Yellow Card scheme, either through the website (https://yellowcard.mhra.gov.uk) or by searching the Google Play or Apple App stores for MHRA Yellow Card.
ENDS
Notes to editors
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The approval was granted to Serum Life Sciences Ltd on 31 October 2025.
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More information can be found in the Summary of Product Characteristics and Patient Information Leaflet, which will be published on the MHRA Products website within 7 days of approval.
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This product was submitted and approved via an international recognition procedure.
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The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for regulating all medicines and medical devices in the UK by ensuring they work and are acceptably safe. All our work is underpinned by robust and fact-based judgements to ensure that the benefits justify any risks.
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The MHRA is an executive agency of the Department of Health and Social Care.
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For media enquiries, please contact newscentre@mhra.gov.uk or call 020 3080 7651.
