This is a randomised, double-blind crossover study to study the effect of intravenous treatment with autologous (derived from the individuals themselves) mesenchymal stem cells (MSCs) in patients with multiple sclerosis (MS).

Current treatments for MS target the immune system and are not curative. There is much interest in MSCs as they have the potential to not only affect the immune system but may also promote repair. This study will use MSCs that are harvested from the bone marrow and grown for up to 52 days before being given back to the person from whom they were harvested. This avoids any chemotherapy so is therefore safer than other types of stem cells. In this crossover study, everyone will receive their own stem cells back but in half of the patients it will be delayed by 24 weeks.

The primary outcomes are to check that the procedure is safe and to measure any changes on the MRI at 24 weeks. Other more exploratory measures will try to assess effects on repair in the central nervous system (CNS).

Inclusion Criteria:

Patients with clinically and radiologically active multiple sclerosis as defined by:

1. Diagnosis of MS:

   • Relapsing remitting MS (RRMS): ≥ 1 moderate-severe relapse and ≥1 GEL in past 18 months or ≥ 1 moderate-severe relapse and ≥1 new T2 lesion in past 18 months.
   • Secondary progressive MS (SPMS) with an increase of ≥ 1 EDSS point (if baseline EDSS ≤ 5) or 0.5 EDSS point (if baseline EDSS ≥ 5.5), in the previous 18 months and ≥ 1 GEL in past 18 months or ≥ 1 moderate-severe relapse and ≥1 new T2 lesion in past 18 months.
   • Primary progressive MS (PPMS) patients with positive oligoclonal bands (OCBs) in the cerebrospinal fluid (CSF) and an increase of ≥ 1 EDSS point (if baseline EDSS is ≤ 5.0) or 0.5 EDSS point (if baseline EDSS is ≥ 5.5), or quantifiable, objective evidence of equivalent progression in the previous 18 months and ≥ 1 GEL in past 18 months or ≥ 1 new T2 lesion in past 18 months.

2. Age 18 to 50 years.

3. Disease duration 2 to 10 years from diagnosis (inclusive).

4. Expanded Disability Status Scale (EDSS) 2.0 to 6.5 at screening evaluation.

5. ≥ 1 GEL on MRI within 6 months prior to harvesting.

6. Adequate culture of a subject's MSCs and their release for clinical use.

Exclusion Criteria:

1. RRMS without at least one severe relapse in the previous 18 months or without at least one GEL or one new T2 in the previous 18 months.
2. SPMS without relapses and without new lesions (GEL or T2 positive) at MRI in the last 18 months.
3. PPMS without positive CSF OCBs or without a GEL or new T2 lesion in the previous 18 months.
4. No gadolinium enhancing lesion(s) in the 3 months prior to bone marrow harvesting.
5. A previously ineligible patient who failed to meet the MRI requirements of the inclusion criteria will not be reviewed again even if further imaging, revealing ≥ 1 GEL, becomes available.
6. Failure of bone marrow (BM) sample to generate MSCs suitable for clinical use within a specified time frame (4 weeks).
7. Treatment with any immunosuppressive therapy, including natalizumab and fingolimod, within the last 3 months.
8. Treatment with interferon-beta or glatiramer acetate within the last 1 month.
9. Treatment with alemtuzumab (campath-1H) within the last 2 years.
10. Prior treatment with total lymphoid irradiation and autologous or allogeneic hematopoietic stem cell transplantation.
11. Participation in clinical trials of any experimental drugs in the 6 months before study entry.
12. Corticosteroid treatment in the last 30 days.
13. Presence of any active or chronic infection.
14. Previous history of a malignancy other than basal cell carcinoma of the skin and carcinoma in situ that has been in remission for more than one year.
15. Severely limited life expectancy by any other co-morbid illness.
16. Abnormal blood counts, a history of myelodysplasia or other cytopenia.
17. Known pregnancy, positive urine pregnancy test at screening or risk or pregnancy (this includes patients who are unwilling to practice active contraception during the duration of the study).
18. Contraindication to MRI including but not limited to intracranial aneurysm clips (except Sugita), history of intra-orbital metal fragments that have not been removed by an MD (as confirmed by orbital X-Ray), pacemaker and non-MRI compatible devices (e.g. heart valves, inner ear implants), history of claustrophobia or the inability of the subject to lie still on their back for a period of 1.5 hours in the MRI scanner.
19. An estimated glomerular filtration rate (eGFR)< 60 mL/min/1.73m2 or history or presence of renal impairment (e.g. serum creatinine clearance less than 30ml/min).
20. Inability to give written informed consent/comply with study procedures.
21. Any significant organ dysfunction or co-morbidity that the Investigators consider would put the subject at unacceptable risk by participating in the study or that would interfere with the functional assessments.

Patients for whom MSCs were successfully expanded after the bone marrow aspirate

12 months