The Medicines and Healthcare products Regulatory Agency (MHRA) has granted approval for Siiltibcy (rdESAT-6 and rCFP-10), a diagnostic aid designed to detect Mycobacterium tuberculosis infection, including active TB disease, in both adults and children. The product, developed by Serum Life Sciences Ltd, received authorisation on 31 October 2025 through an international recognition procedure.
Tuberculosis (TB) is an airborne infectious disease that primarily affects the lungs but can spread to other organs. Timely diagnosis remains critical for preventing transmission and improving treatment outcomes.
How Siiltibcy Works
Siiltibcy is administered as an intradermal injection on the forearm. It contains two laboratory-produced proteins—rdESAT-6 and rCFP-10—specific to Mycobacterium tuberculosis. In individuals infected with TB bacteria, the immune system reacts to these proteins by releasing cytokines, leading to a firm, raised area (induration) at the injection site. This reaction typically appears 48–72 hours after administration. The size of the induration helps determine whether the person has been infected or may have TB disease.
Evidence and Safety
The approval of Siiltibcy is supported by data from three major clinical studies involving more than 2,000 participants, including paediatric subjects. The most frequently reported side effect was itching (pruritus) at the injection site, occurring in more than 10% of individuals. A complete list of side effects will be detailed in the Patient Information Leaflet (PIL) and the Summary of Product Characteristics (SmPC), to be published on the MHRA website within seven days of approval.
Ongoing Monitoring
The MHRA will continue to closely monitor the safety and effectiveness of Siiltibcy. Patients, caregivers, and healthcare professionals are encouraged to report suspected side effects through the MHRA Yellow Card scheme online or via the mobile app.
The MHRA oversees the regulation of all medicines and medical devices in the UK, ensuring they meet standards of safety, quality, and effectiveness as part of its role within the Department of Health and Social Care.
