Relationship between methotrexate in red and white blood cells with disease activity: towards optimal methotrexate dosing in rheumatoid arthritis.

Conditions: Rheumatoid arthritis, methotrexate therapy, PBMC, therapeutic drug monitoring

Registration Number: NL-OMON20053

Lead Sponsor: Reade Reumatology, Amsterdam

Brief Summary: .A.

Detailed Description: Not available

Recruitment & Eligibility

Status: Other

Sex: Not specified

Target Recruitment: 40

Inclusion Criteria

Adults

- Diagnosis of rheumatoid arthritis

Exclusion Criteria

- Rheumatic autoimmune disease other than RA, e.g., systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), scleroderma, polymyositis

- Subjects who have received an investigational drug within 30 Days prior to the screening visit, known sensitivity to any component of the study drug or previous hypersensitivity reaction or other clinically significant reaction to s.c. medications, any clinically significant hepatic, renal, cardiac, pulmonary, gastrointestinal, metabolic or endocrine disturbances, other medical or psychiatric condition, or clinically relevant abnormal values on any investigation, which in the opinion of the investigator, could make the subject unsuitable for the study, could compromise subject safety, limit the subject’s ability to complete the study, and/or compromise the objectives of the study.

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
# Is there a relationship between levels of MTX-PGn (1-5) accumulation in RBCs vs PBMCs after oral MTX treatment and is this associated/correlated with DAS-28 scores.<br /><br># Is any inter-patient variability in MTX-PGn accumulation in RBCs and PBMCs associated/correlated with specific FPGS splicing alterations.

Secondary Outcome Measures

Name	Time	Method
Are there other determinants accounting for variabilities in RBC and/or PBMC MTX-PGn<br>accumulation:<br /><br># Socio-demographic parameters (age, sex).<br /><br># Medication adherence, assessed via the compliance questionnaire for rheumatology (CQR), pill/syringe count and refill rate.<br /><br># Intracellular folate levels, FPGS and ABC transporter gene polymorphisms, age, and MTX dose.<br /><br># Clinical variables (e.g., BMI, smoking), kidney function and co-medication.