Study of Neuroinflammation in Multiple Sclerosis by PET-MRI Imaging Using the Radiotracer ([18F]-DPA-714) : a Multicentre Cohort Study (INFLANET)

INFLANET is a multicentric, prospective, non-randomized, non-blinded, interventional study.The study will include a total of 41 participants, with 18 individuals diagnosed with multiple sclerosis (MS) distributed across three sites (6 patients per site: Paris, Lyon, Rennes). Additionally, there will be 23 healthy volunteers (HV), with 20 HV allocated to the Lyon and Rennes sites (10 HV per site) and 3 HV for the Paris site.

The study involves several clinical visits, with two visits for patients (Screening V0 and Baseline V1), two visits for 20 healthy volunteers (Screening V0 and Baseline V1), and three visits for three healthy volunteers (Screening V0, Baseline V1 - Test, and V1' - Retest, in Paris site). Various evaluations are integrated into the study, including neurological assessments at the screening visit, neuropsychological assessments at the baseline visit, 18F-DPA714 PET-MR or PET + MRI (n=1 for 20 HV and 18 subjetcs with MS; n=2 for 3 HV) at V1 and V1', and blood sampling at the screening visit to confirm TSPO eligibility.

The PET-MR procedure involves TSPO PET using [18F]-DPA-714 in conjunction with 3T MRI for both MS patients and healthy volunteers. Gadoteric acid is administered for MS patients only as part of the imaging.

Inclusion criteria

RRMS patients:

• Age between 18 and 55 years old
• RRMS according to the 2017 Mc Donald criteria
• At least 9 supra-tentorial white matter lesions on T2/FLAIR MRI
• Last treatment with methylprednisolone should have been performed at least 1 month before PET examinations
• No current disease modifying therapy
• Indication for a highly active disease modifying treatment: Natalizumab, anti CD20 antibody, Alemtuzumab, sphingosine-1 phosphate modulator, or cladribine. This will consist either as patients with an active form of relapsing MS or patients who have experienced two relapses during the previous year
• Affiliation to a social security scheme or beneficiary of such a scheme (except "Aide Médicale d'Etat")

Healthy Volunteers:

• Age between 18 and 55 years old
• Without any evolutive pathology
• Able to understand the study objectives and procedures
• Affiliation to a social security scheme or beneficiary of such a scheme (except "Aide Médicale d'Etat")

Exclusion criteria

For all participants:

• Any reasons, which does not allow to perform MRI, including claustrophobia, the implant of a pace-maker or the presence of an intra-ocular foreign body, (a contra-indication questionnaire will be filled in beforehand)
• Realization of any test using radioactivity within the last 12 months
• Low Affinity Binding profile (analyse of TSPO polymorphism done at screening visit)
• Pregnancy, breast-feeding, lack of efficient contraception for women of childbearing potential
• Current symptoms of severe or uncontrolled renal, hepatic, hematological, gastrointestinal, pulmonary or cardiac disease, or any other chronic neurological diseases
• Unwillingness to be informed in case of unexpected MRI abnormality (with a significant medical anomaly)
• Patient under legal protection
• Participation in another interventional study or being in the exclusion period at the end of a previous study

RRMS patients:

• Hypersensitivity to gadoteric acid
• Meglumine or any drug containing gadolinium
• Severe renal insufficiency (creatinine clearance < 60mL/min and GFR <30ml / min / 1.73m2).