Clinical Research Directory

Inclusion Criteria: * Patients with MS who are being treated with oral cladribine at Barts Health NHS Trust will be approached to participate in this study. * Patients must be willing and able to undergo lumbar punctures * Patients who are OCB positive in their CSF (previous diagnostic lumbar puncture) Exclusion Criteria: * Ineligible for oral cladribine under NHS England prescribing guidelines and those participating in MAGNIFY-MS study (cladribine tablets in active MS) * Unsuitable to have a lumbar puncture, for example spinal deformity, tethered cord syndrome or the use of aspirin or anticoagulants, and those unable to comply with study requirements, including frequency of visits and lumbar punctures. * Presence of comorbidities in which the administration of cladribine is contraindicated. * Abnormal baseline investigations (WBC\<3 x 10\*9/l, lymphocytes \<1.0 x 10\*9/l, neutrophil count \<1.5 x 10\*9/l, platelet count \<100 x 10\*9, haemoglobin \<110g/l, LFT\>/3x upper limit of normal of site reference ranges, potassium \<2.8mmol/l or \>5.5mmol/l, sodium \<125 mmol/l, creatinine \>130 umol/l)