Multiple sclerosis (MS) is a disabling and progressive neurological disease that affects approximately 100,000 people in the UK. Many patients with MS experience two phases of disease; early MS (also called relapsing remitting MS, RRMS) and late MS (also called secondary progressive MS (SPMS). Early MS is due to inflammation of the nerves and the insulation (called myelin) that surrounds the nerves. Early MS is often characterised by periods of "attacks" interspersed with periods of "remission" with no or low disease symptoms. Late or progressive MS, which affects the majority of patients and typically emerges after 10-15 years of disease, results from actual nerve death (also called neurodegeneration). The progressive stage of disease results not in individual attacks but slow, cumulative and irreversible disability affecting walking, balance, vision, cognition, pain control, bladder and bowel function. Critically, and unlike early disease, there is no proven treatment for the late stage of MS. This is therefore an urgent and major unmet health need. MS-SMART directly addresses this need and will evaluate in this clinical trial three drugs (fluoxetine, riluzole or amiloride), all of which have shown some promise in MS, and in particular in SPMS. The trial is randomised and blinded. Randomisation means patients can get any one of the three active drugs or the inactive placebo/dummy; blinded means that neither patients nor the doctors will know which drug or placebo patients are receiving. Randomisation and blinding are standard approaches in clinical trials to ensure unbiased testing of drugs. All patients in MS-SMART will have periodic MRI (magnetic resonance imaging) brain scans and after 96 weeks these will be analysed. We will then compare the scans of each drug to the placebo or dummy to see if any of the drugs slow the rate of brain shrinkage that normally occurs in SPMS. This measured change in brain size is the primary (major) outcome of MS-SMART.

MS-SMART will test the efficacy and mechanism of action of three repurposed drugs (fluoxetine, riluzole and amiloride). All three drugs are in human use and have a good safety record. Critically for the purpose of MS-SMART they all have shown promise in early phase human MS clinical trials and target one or more of the pivotal neurodegenerative causing pathways implicated in SPMS. This is a Type B trial, as the IMPs are all in human use, have a good safety profile but are not currently used for this patient population.

The major need for patients with established and progressive MS is neuroprotective or disease modifying treatments that will slow or even stop disease progression. This study will evaluate three highly promising putative neuroprotective drugs as well as comprehensively address several of the current knowledge gaps related to the understanding of neuroprotection and neurodegeneration in SPMS through MRI and CSF examination.

MS-SMART is a multicentre, multi-arm, double blind, placebo-controlled phase IIb randomised controlled trial. A total of 440 patients with SPMS, with an entry criteria of an EDSS score of 4.0-6.5 will be equally randomised to receive placebo or one of the three active agents (fluoxetine 20mg bd, amiloride 5mg bd or riluzole 50mg bd). Patients will be followed up for 96 weeks with outcome-data collected after 0, 24, 48 and 96 weeks. That is, the duration of the trial for a trial participant is 96 weeks (a telephone assessment at week 100, 4 weeks post completion will be conducted). This is standard practice for phase II trials in SPMS.

Inclusion Criteria:

• Confirmed diagnosis of SPMS. Steady progression rather than relapse must be the major cause of increasing disability in the preceding 2 years. Evidence of progression, either an increase of at least one point in EDSS or clinical documentation of increasing disability in patient notes
• Expanded Disability Status Scale (EDSS) 4.0-6.5
• Aged 25 to 65 inclusive
• Women and men with partners of childbearing potential must be using an appropriate method of contraception to avoid any unlikely teratogenic effects of the 3 drugs from time of consent, to 6 weeks after treatment inclusive
• Women must have a negative pregnancy test within 7 days prior to the baseline visit unless not of child bearing potential (e.g. have undergone a hysterectomy, bilateral tubal ligation or bilateral oophorectomy or they are postmenopausal)
• Willing and able to comply with the trial protocol (e.g. can tolerate MRI and fulfils the requirements for MRI, e.g. not fitted with pacemakers or permanent hearing aids), ability to understand and complete questionnaires
• Written informed consent provided

Exclusion Criteria:

• Pregnancy or breast feeding patients
• Baseline MRI scan not of adequate quality for analysis (e.g. too much movement artefact)
• Significant organ co-morbidity (e.g. malignancy or renal or hepatic failure)
• Relapse within 3 months of baseline visit
• Patients who have been treated with iv or oral steroids for an MS relapse/progression within 3 months of baseline visit (these patients can undergo future screening visits once the 3 month window has expired), patients on steroids for another medical condition may enter as long as the steroid prescription is not for multiple sclerosis (relapse/ progression).
• Use of Simvastatin at 80mg dose within 3 months of baseline visit (lower doses of Simvastatin and other statins are permissible)
• Commencement of fampridine within 6 months of baseline visit
• Use of immunosuppressants (e.g. azathioprine, methotrexate, cyclosporine) or disease modifying treatments (β-interferons, glatiramer) within 6 months of baseline visit
• Use of fingolimod/fumarate/teriflunomide/laquinomod/or other experimental disease modifying treatment (including research of an investigational medicinal product) within 12 months of baseline visit
• Use of mitoxantrone/ natalizumab/ alemtuzumab/ daclizumab if treated within 12 months of baseline visit
• Primary progressive MS
• Relapsing-remitting MS
• Known hypersensitivity to the active substances and their excipients to any of the active drugs for this trial
• Use of: lithium, chlorpropamide, triamterene and spironolactone within 6 months of the baseline visit
• Current use of potassium supplements
• Current use of tamoxifen
• Current use of herbal treatments containing St. John's Wort
• Significant signs of depression
• Use of an SSRI within 6 months of the baseline visit
• Use of monoamine oxidase inhibitors, phenytoin, L-tryptophan) and/or neuroleptic drugs within 6 months of the baseline visit
• A Beck Depression Index score of 19 or higher
• Bipolar disorder
• Receiving or previously received Electro-Convulsive Therapy
• Epilepsy/seizures
• Glaucoma
• Patients with a history of bleeding disorders or currently on anticoagulants Routine screening blood values (LFT) >/ 3 x upper limit of normal (ULN) of site reference ranges (ALT/AST, bilirubin,ˠGT) Potassium <2.8mmol/l or >5.5mmol/l
• Sodium <125mmol/l
• Creatinine >130μmol/l
• WBCs <3 x 109/l
• Lymphocytes <0.8 x 109/l
• Neutrophil count <1.0 x 109 /l
• Platelet count <90 x 109 /l
• Haemoglobin <80g/l