Autologous Hematopotoietic Stem Cell Transplantation in Multiple Sclerosis with An Intermediate Intensity Conditioning Regimen: The Italian Multi-Centre Experience

Abstract 334 Background: Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease believed to be mediated by autoreactive lymphocytes that invade the Central Nervous System and cause oligodendrocyte, axonal and neuronal damage as well as glial scarring.to and resulting in demyelination, neuronal death and brain atrophy. Hematopoietic Stem Cell Transplantation (HSCT) has been tried in the last 15 years as a therapeutic option in patients with a poor prognosis autoimmune disease not responding to conventional treatments. Worldwide ≥600 patients with MS have been treated with HSCT, most of them having been recruited in small, single center, phase 1–2 uncontrolled trials. Clinical and MRI outcomes from case series reports or Registry-based analyses suggest that a major response is achieved in most patients; quality and duration of response are better in patients transplanted earlier in the relapsing-remitting phase. The intensity of the immunosuppression from transplant treatment may be determined by several factors, such as the use of chemotherapy in the mobilization regimen, the intensity of the conditioning regimen and ex-vivo T-cell depletion. Methods: We report here the Italian multi-center experience on 74 MS patients treated with AHSCT between 1996 and 2008, all mobilized with Cyclophosphamide/G-CSF and conditioned with BEAM and rabbit ATG. Clinical and MRI outcomes were reported to the Italian Registry; the median follow-up is 48.3 (range 30–210) months. All patients clinically deteriorated in the year prior to HSCT, with an increase of Extended Disability Scale (EDSS) of at least one point (average EDSS change=1.5 points, range=1–9), Results: Two patients (3.3%) died for transplant-related causes. At 5 years after the transplant, 66% of patients remained stable or improved. Progression free survival (PFS) was slightly better in relapsing-remitting (RR) (5 years PFS=71%) than in secondary-progressive (SP) forms (5 years PFS=62%, p=0.28). Amongst patients with a follow up longer than 1 year, 8 out of 25 RR subjects (31%) had a 6–12 months confirmed EDSS improvement > 1 point as compared to 1 out of 36 (3%) SP patients (p=0.009), Figure 1. Out of 18 cases with a follow up longer than 7 years, 8 (44%) remained stable or had a sustained improvement whilst 10 (56%), after an initial period of stabilization or improvement with a median duration of 3.5 years, showed a slow progression of disability. Conclusions: This study shows in a large cohort of patients with a long follow-up that AHSCT with BEAM/ATG conditioning regimen has a profound effect in suppressing disease progression in aggressive MS cases, unresponsive to conventional therapies. Indeed it results in a sustained improvement of the disability, free of immunosuppression, in a significant amount of RR patients. Clinical improvement is scarcely reported in MS literature as it is rather infrequent with conventional treatments; nevertheless it results in a stable increase of the quality of the life in this subset of young patients and should be considered in the choice of a therapeutic strategy in the early phase of MS. Disclosures: Cuneo: Roche: Consultancy, Speakers Bureau.