The primary objective of the study is to investigate neuroregenerative efficacy (proof of concept) of intrathecal treatment with autologous MSCs as measured by neurophysiological parameters in patients with progressive MS.

Secondary objectives are to assess neuroregenerative efficacy as measured by other neurophysiological parameters as well as clinical, opthalmological and MRI modalities, and to assess safety of the treatment procedure.

Prospective, interventional, randomized, placebo-controlled, cross-over study. Patients are randomized to either treatment arm A or B.

Patients in both treatment arms receive intrathecal autologous MSCs, arm A at baseline and arm B at six months.

All patients undergo bone marrow (BM) aspiration prior to baseline. Patients in treatment arm A receive intrathecal autologous MSCs whereas patients in treatment arm B receive placebo. The treatment is blinded for the patients. The BM aspirate from patients in treatment arm B is processed, cryopreserved and stored in a biobank.

At six months, all patients undergo a second BM aspiration. Patients in treatment arm A now receive placebo. The BM aspirate from patients in treatment arm A is processed, cryopreserved and stored in a biobank. Patients in treatment arm B receive intrathecal autologous MSCs. The treatment is blinded for the patients.

Primary outcome is assessed at six months and secondary outcomes are assessed at six, twelve and eighteen months post baseline. Investigator assessing outcomes are blinded to patient treatment allocation.

Inclusion Criteria:

1. Age ≥18 to ≤55, both genders
2. Diagnosis of secondary progressive or primary progressive MS using revised McDonald criteria of clinically definite MS
3. An EDSS score of 4 to 7
4. Disease duration 2 - 15 years
5. Signed, written informed consent

Exclusion Criteria:

1. Any illness or prior/ongoing treatment that in the opinion of the investigators would jeopardize the ability of the patient to tolerate autologous stem cell treatment
2. Any ongoing infection, including Tbc, CMV, EBV, HSV, VZV, hepatitis virus, toxoplasmosis, HIV or syphilis infections, as well as heaptitis B surface antigen positivity and/or hepatitis C PCR positivity
3. Current immunomodulatory/immunosuppressive treatment
4. Immunomodulatory/immunosuppressive treatment within 6 months prior to inclusion. This includes, but is not restricted to treatment with natalizumab, fingolimod, dimetylfumurat, glatiramer acetate, interferon beta medications, teriflunomide, and siponimod.
5. Treatment with kladribin, ocrelizumab, rituximab, and alemtuzumab within 12 months prior to inclusion
6. Treatment with hematopoietic stem cell therapy within 12 months prior to inclusion
7. Treatment with glucocorticoids or ACTH within three months prior to start of inclusion
8. Having experienced an MS relapse within 2 years prior to study inclusion
9. Current treatment with fampridin
10. History of malignancy other than basal cell carcinoma of the skin or carcinoma in situ that has been in remission for more than one year
11. Severely limited life expectancy by another co-morbid illness
12. History of previous diagnosis of myelodysplasia or previous hematologic disease (including lymphoproliferative disease, bone marrow insufficiency or previous lymphoid irradiation) or current clinically relevant abnormalities of white blood cell counts
13. Immunocompromised patients
14. Estimated glomerular filtration rate <60 ml/min/1.73 m2 or known renal failure
15. Bleeding or clotting diathesis or the use of antithrombotic or anticoagulative treatment
16. Platelet (thrombocyte) count <100 x 10*9/L
17. Participation in another experimental clinical study within the preceding 12 months
18. Contraindications to MRI
19. Prior or current major depression
20. Prior or current psychiatric illness, mental deficiency or cognitive dysfunction influencing the patient ability to make an informed consent or comply with the treatment and follow-up phases of this protocol.
21. Pregnancy or risk of pregnancy (this includes patients that are unwilling to practice active contraception during the duration of the study), breastfeeding or lactation
22. History of autologous/allogenic bone marrow transplantation or peripheral blood cell transplant
23. Known hypersensitivity against paracetamol, codein or xylocain
24. Diagnosis or strong suspicion of polyneuropathy
25. Prior or current alcohol or drug dependencies
26. Inability to give informed consent