NCT06654154

Vitamin B12: a Biological Marker of Systemic Disease or Infection Flare-up in Patients Treated with Tocilizumab?

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 56 (estimated)
• Sponsor: University Hospital, Clermont-Ferrand · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Tocilizumab is a monoclonal antibody that acts as an IL-6 receptor antagonist It is responsible for a reduction in the hepatic synthesis of inflammatory proteins, including CRP (C-reactive protein). Thus, the diagnosis of a relapse of the autoimmune or auto inflammatory disease (AI/ID) or an infection is made difficult in patients treated with tocilizumab and there is to date no marker of inflammation validated in patients receiving tocilizumab. Vitamin B12 is an essential element that participates to haematopoiesis, myelin integrity, neuronal function and DNA synthesis. Vitamin B12 is carried by haptocorrin and transcobalamin II (TCII). Vitamin B12 increases in many pathological situations, including infections and AI/ID due to the increase of its transport proteins elevation (mostly transcobalamin II). The sponsor did not find any study in the literature studying the level of vitamin B12 or TCII in patients taking tocilizumab. The sponsor also did not find any physiopathological argument in favor of an inhibition of TCII synthesis by tocilizumab. As such, TCII dosage could be of interest, but the dosage is not available in routine whereas vitamin B12 dosage is available in every laboratory and is four times cheaper.

Detailed description

The main objective is to study the variation in serum vitamin B12 level in case of clinical suspicion of AID/I flare or infection in patients treated with tocilizumab compared to the B12 level of the patient in remission period. , and excluding infection, under tocilizumab Also, serum vitamin B12 will be measured during a biological assessment carried out either in the event of a suspected outbreak of MAI/I or infection, or in the event of remission (during the follow-up assessment carried out systematically in a patient on tocilizumab). This determination of serum vitamin B12 will be carried out during a blood test carried out at the request of the patient's doctor. The study will involve taking an additional tube of venous blood but will not result in additional venipuncture. There will be no specific visit related to the study.

Conditions

• Level of Serum Vitamin B12 Level (in Pmol/L) If Relapse of (AI/ID) Under Tocilizumab
• Level of Serum Vitamin B12 Level (in Pmol/L) If Infection Under Tocilizumab

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	variation of serum level vitamine B12	There will be no specific visit to the study. Follow-up in consultation will be done by your referring doctor. A determination of the serum level of vitamin B12 will be carried out at inclusion, during a consultation where the pathology is in remission (during the classic assessment of follow-up under tocilizumab, left to the discretion of the patient's referring doctor. ). It will also be necessary to carry out, in addition to the classic assessment left to the discretion of the patient's doctor, a determination of the serum level of vitamin B12 in the event of clinical suspicion of infection or an outbreak of MAI/I. The determination of serum vitamin B12 requires the collection of an additional tube of 300 μl of venous blood but no additional venipuncture

Timeline

• Start date: 2024-04-03
• Primary completion: 2026-03-01
• Completion: 2029-03-01
• First posted: 2024-10-23
• Last updated: 2024-10-23

Locations

1 site across 1 country: France