Repeat Infusion of Autologous Bone Marrow Cells in Multiple Sclerosis (SIAMMS-II)

On the background of our own and others' experimental BM stem cell studies, we recently completed a phase 1 feasibility/safety trial of BM cell therapy in 6 patients with longstanding progressive MS (www.nature.com/clpt/journal/v87/n6/full/clpt201044a.html). Safety was confirmed, and intensive serial neurophysiological tests showed statistically significant improvements at 12 months. While highly preliminary and entirely uncontrolled, these results at least raise the possibility of a beneficial effect within the damaged central nervous system (CNS). A phase 2 clinical trial to formally assess efficacy of intravenous infusion of autologous bone marrow cells in progressive MS will commence in the near future (ACTiMuS trial). This trial comprises a programme of translational and clinical stem cell research, aiming (1) to continue translation with a phase two controlled trial of autologous bone marrow cells (BMCs) in chronic MS; and (2) to explore in parallel the potential mechanisms of action by studying BM cells from treated patients and controls, aiming to establish which BM sub-population(s) contribute(s) to efficacy, and which reparative mechanism(s) are important.

It is not known whether repeated infusion of autologous bone marrow offers additional benefit or how long improvements might be expected to last. The current proposal seeks to explore whether the neurophysiological improvements observed in the phase I study persist several years after the initial single infusion and whether these can be either replicated or augmented by an additional infusion of autologous bone marrow cells.

Hypothesis and aims

We hypothesise that intravenously-delivered autologous bone marrow cellular therapy (BMCT) in chronic MS offers significant benefit. We hypothesize also that the mechanisms are multiple, and include immunomodulation and reparative and/or neuroprotective effects within the CNS; and are offered by one or more BM stem cell sub-populations, jointly contributing to the therapeutic impact. Exploring and understanding these mechanisms, and the biology of the cells responsible, will allow the development of more effective reparative cell therapy in MS.

The current study seeks to examine whether the observed improvements noted in conduction times in central nervous system pathways in the phase I 'Study of Intravenous Autologous Marrow in Multiple Sclerosis (SIAMMS)' persist several years following the initial single infusion and whether these can be either replicated or augmented by an additional infusion of autologous bone marrow cells and analysis of research samples will be performed as per samples included in the concurrent phase 2 clinical trial 'Assessment of bone marrow-derived cellular therapy in progressive multiple sclerosis (ACTiMuS)' (REC 12/SW/0358, ISRCTN27232902, NCT01815632).