Intermediate-Intensity Autologous Hematopoietic Stem Cell Transplantation Reduces Serum Neurofilament Light Chains and Brain Atrophy in Aggressive Multiple Sclerosis.

Background: Autologous haematopoietic stem cell transplantation (AHSCT) is highly effective in reducing new inflammatory activity in aggressive multiple sclerosis (MS). A remarkable decrease of serum neurofilament light chains (sNfL) concentration, a marker of axonal damage, was reported in MS following high-intensity regimen AHSCT, but hints for potential neurotoxicity had emerged. sNfL and brain atrophy were therefore analysed in a cohort of patients with aggressive MS treated with intermediate-intensity AHSCT, exploring whether sNfL might be a reliable marker of disability progression independent from new inflammation (i.e. relapses and/or new/gadolinium-enhancing MRI focal lesions). Methods: sNfL concentrations were measured using SIMOA methodology in peripheral blood from relapsing-remitting (RR-) or secondary-progressive (SP-) MS patients undergoing AHSCT (MS AHSCT), collected before transplant and at months 6 and 24 following the procedure. sNfL measured at a single timepoint in SP-MS patients not treated with AHSCT without recent inflammatory activity (SP-MS CTRL) and healthy subjects (HD) were used as controls. The rate of brain volume loss (AR-BVL) was also evaluated by MRI in MS AHSCT cases. Results: Thirty-eight MS AHSCT (28 RR-MS; 10 SP-MS), 22 SP-MS CTRL and 19 HD were included. Baseline median sNfL concentrations were remarkably higher in the MS AHSCT than in the SP-MS CTRL and HD groups (p = 0.005 and <0.0001, respectively), and levels correlated with recent inflammatory activity. After a marginal (not significant) median increase observed at month 6, at month 24 following AHSCT sNfL concentrations decreased compared to baseline by median 42.8 pg/mL (range 2.4-217.3; p = 0.039), reducing by at least 50% in 13 cases, and did not differ from SP-MS CTRL (p = 0.110) but were still higher than in HD (p < 0.0001). Post-AHSCT AR-BVL normalised in 55% of RR-MS and in 30% of SP-MS. The effectiveness and safety of AHSCT were aligned with the literature. Conclusion: sNfL concentrations correlated with recent inflammatory activity and were massively and persistently reduced by intermediate-intensity AHSCT. Association with response to treatment assessed by clinical or MRI outcomes was not observed, suggesting a good sensitivity of sNfL for recent inflammatory activity but low sensitivity in detecting ongoing axonal damage independent from new focal inflammation.

Impact of autologous haematopoietic stem cell transplantation on disability and brain atrophy in secondary progressive multiple sclerosis.

BACKGROUND: Autologous haematopoietic stem cell transplantation (aHSCT) is a valuable option in aggressive relapsing-remitting multiple sclerosis (MS), but its efficacy in secondary progressive (SP)-MS is still controversial. OBJECTIVE: Assessing efficacy of aHSCT in SP-MS by clinical-radiological outcomes. METHODS: Open-label monocentric retrospective study enrolling consecutive SP-MS patients treated with BEAM-aHSCT in the period 1999-2016. RESULTS: In total, 26 SP-MS patients with moderate-severe disability were included. Progression-free survival (PFS) at years 5 and 10 after aHSCT were, respectively, 42% and 30%. Out of 16 patients who worsened, only 6 patients (23% overall) maintained continuous disability accrual (CDA), whereas 10 patients stabilized following one single-step Expanded Disability Status Scale (EDSS) worsening. CDA-free survival was 74% at 5-10 years. No relapses or magnetic resonance imaging (MRI) activity were reported, thus no evidence of disease activity (NEDA)-3 corresponded to PFS. Annualized rate of brain atrophy (AR-BVL) normalized after 1 year in 55% of the cases analysed (12/22). CONCLUSION: BEAM-aHSCT halted CDA and normalized AR-BVL in most of the treated patients, inducing long-term remission of inflammatory activity at a median follow-up of 99 months (range 27-222). These data suggest that CDA might still be mainly driven by inflammation in a subgroup of SP-MS and could therefore be reversed by treatments. CDA should be analysed independently from any isolated disability worsening.