Refractory Multiple Sclerosis Research Articles

Reconsidering the route of drug delivery in refractory multiple sclerosis: Toward a more effective drug accumulation in the central nervous system.

Multiple sclerosis is a chronic demyelinating disease with different disease phenotypes. The current FDA-approved disease-modifying therapeutics (DMTs) cannot cure the disease, but only alleviate the disease progression. While the majority of patients respond well to treatment, some of them are suffering from rapid progression. Current drug delivery strategies include the oral, intravenous, subdermal, and intramuscular routes, so these drugs are delivered systemically, which is appropriate when the therapeutic targets are peripheral. However, the potential benefits may be diminished when these targets sequester behind the barriers of the central nervous system. Moreover, systemic drug administration is plagued with adverse effects, sometimes severe. In this context, it is prudent to consider other drug delivery strategies improving their accumulation in the brain, thus providing better prospects for patients with rapidly progressing disease course. These targeted drug delivery strategies may also reduce the severity of systemic adverse effects. Here, we discuss the possibilities and indications for reconsideration of drug delivery routes (especially for those "non-responding" patients) and the search for alternative drug delivery strategies. More targeted drug delivery strategies sometimes require quite invasive procedures, but the potential therapeutic benefits and reduction of adverse effects could outweigh the risks. We characterized the major FDA-approved DMTs focusing on their therapeutic mechanism and the potential benefits of improving the accumulation of these drugs in the brain.

Immunoadsorption versus double-dose methylprednisolone in refractory multiple sclerosis relapses

ObjectiveIntravenous methylprednisolone is the standard treatment for a multiple sclerosis relapse; however, this fails to improve symptoms in up to one quarter of patients. Immunoadsorption is an accepted treatment for refractory relapses, but prospective comparator-controlled studies are missing.MethodsIn this observational study, patients with steroid-refractory acute multiple sclerosis relapses receiving either six courses of tryptophan-immunoadsorption or double-dose methylprednisolone therapy were analysed. Outcomes were evaluated at discharge and three months later. Immune profiling of blood lymphocytes and proteomic analysis were performed by multi-parameter flow cytometry and Olink analysis, respectively (NCT04450030).Results42 patients were enrolled (methylprednisolone: 26 patients; immunoadsorption: 16 patients). For determination of the primary outcome, treatment response was stratified according to relative function system score changes (“full/best” vs. “average” vs. “worse/none”). Upon discharge, the adjusted odds ratio for any treatment response (“full/best” + ”average” vs. “worse/none”) was 10.697 favouring immunoadsorption (p = 0.005 compared to methylprednisolone). At follow-up, the adjusted odds ratio for the best treatment response (“full/best” vs. “average” + ”worse/none”) was 103.236 favouring IA patients (p = 0.001 compared to methylprednisolone). Similar results were observed regarding evoked potentials and quality of life outcomes, as well as serum neurofilament light-chain levels. Flow cytometry revealed a profound reduction of B cell subsets following immunoadsorption, which was closely correlated to clinical outcomes, whereas methylprednisolone had a minimal effect on B cell populations. Immunoadsorption treatment skewed the blood cytokine network, reduced levels of B cell-related cytokines and reduced immunoglobulin levels as well as levels of certain coagulation factors.InterpretationImmunoadsorption demonstrated favourable outcomes compared to double-dose methylprednisolone. Outcome differences were significant at discharge and follow-up. Further analyses identified modulation of B cell function as a potential mechanism of action for immunoadsorption, as reduction of B cell subsets correlated with clinical improvement.

Therapeutic Strategy for Multiple Sclerosis Resistant to Standard Treatment: Refractory MS

In Japan, disease-modifying drugs for multiple sclerosis have amounted to eight, to date, providing us with various therapeutic choices. However, we still encounter difficult cases resistant to these drugs. This review summarizes the diagnostic and therapeutic strategies for refractory multiple sclerosis by presenting suggestive cases.

Connectomic analysis of unilateral dual-lead thalamic deep brain stimulation for treatment of multiple sclerosis tremor.

Tremor is a common symptom in multiple sclerosis and can present as a severe postural and action tremor, leading to significant disability. Owing to the diffuse and progressive nature of the disease, it has been challenging to characterize the pathophysiology underlying multiple sclerosis tremor. Deep brain stimulation of the ventralis intermedius and the ventralis oralis posterior thalamic nuclei has been used to treat medically refractory multiple sclerosis tremors with variable results. The aim of this study was to characterize multiple sclerosis tremor at the network level by applying modern connectomic techniques to data from a previously completed single-centre, randomized, single-blind prospective trial of 12 subjects who were treated with unilateral dual-lead (ventralis intermedius + ventralis oralis posterior) thalamic deep brain stimulation. Preoperative T1-weighted MRI and postoperative head CTs were used, along with applied programming settings, to estimate the volume of tissue activated for each patient. The volumes of tissue activated were then used to make voxel-wise and structural connectivity correlations with clinically observed tremor suppression. The volume of the tissue-activated analyses identified the optimal region of stimulation at the ventralis oralis posterior ventralis intermedius border intersecting with the dentato-rubro-thalamic tract. A regression model showed strong connectivity to the supplemental motor area was positively associated with tremor suppression (r = 0.66) in this cohort, whereas connectivity to the primary motor cortex was negatively associated with tremor suppression (r = −0.69), a finding opposite to that seen in ventralis intermedius deep brain stimulation for essential tremor. Comparing the structural connectivity to that of an essential tremor cohort revealed a distinct network that lies anterior to the essential tremor network. Overall, the volumes of tissue activated and connectivity observations converge to suggest that optimal suppression of multiple sclerosis tremor will likely be achieved by directing stimulation more anteriorly toward the ventralis oralis posterior and that a wide field of stimulation synergistically modulating the ventralis oralis posterior and ventralis intermedius nuclei may be more effective than traditional ventralis intermedius deep brain stimulation at suppressing the severe tremors commonly seen in complex tremor syndromes such as multiple sclerosis tremor.

FTY720 in resistant human epidermal growth factor receptor 2-positive breast cancer

The prognosis of patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer has considerably improved. However, no reliable treatment besides anti-HER2 strategies has been available. FTY720, a small-molecule compound used for treating refractory multiple sclerosis, has been reported to have beneficial effects against cancers. We therefore evaluated the efficacy of FTY720 in trastuzumab-resistant breast cancer cells and investigated the possible mechanism involved. This study evaluated morphological changes after FTY720 treatment. Antiproliferative WST-1 assays and LDH Cytotoxicity Assay Kits were used to determine the treatment effects of drugs, whereas Western blot analysis was used to evaluate protein expression. Apoptotic events were investigated through annexin V staining and TUNEL assays using flow cytometry. FTY720 was effective in trastuzumab-resistant breast cancer cell lines despite the presence of PIK3CA mutation. Studied on a xenograft mouse model, FTY720-treated groups had statistically significantly poorer HCC1954 xenograft growth in vivo compared with the control group. Our findings suggest that FTY720 can overcome resistance to trastuzumab therapy in patients with HER2-positive breast cancer, with FTY720 plus trastuzumab might offer even better efficacy in vitro and in vivo.

BTK inhibitors as potential therapies for multiple sclerosis

Over the past 30 years increasing numbers of molecules have been developed for treatment of multiple sclerosis. However, given the heterogeneity of the disease and the fact that many patients have refractory or progressive multiple sclerosis, new therapeutic alternatives are still needed. Tyrosine kinases are enzymes that mediate phosphorylation of tyrosine residues on downstream molecules that participate in signalling pathways. These kinases have crucial roles in cellular proliferation and differentiation, cell growth and metabolism, and survival and apoptosis, making them potential therapeutic targets in various autoimmune and lymphoproliferative diseases.

Autologous Hematopoietic Stem Cell Transplantation (AHSCT) in Advanced, Treatment Refractory Multiple Sclerosis (MS) — a Phase II Clinical Trial

Aim: Ablation of auto-reactive immune cells followed by autologous hematopoietic stem cell transplantation (AHSCT) in the treatment of multiple sclerosis (MS) has been explored for the previous two decades. Morbidity and mortality rates originally limited referral for AHSCT in auto-immune disease but a reduction in treatment toxicity has facilitated increased clinical trials in the field. Here we present the outcomes of patients withadvanced, treatment refractory MS undergoing AHSCT in a Phase II study at our institute. We evaluate the safety and efficacy of AHSCT with intermediate-intensity immunosuppression in patients with highly aggressive MS.Methods: A single-centre, phase II clinical trial of AHSCT for patients with active relapsing remitting (RRMS) and secondary progressive MS (SPMS) commenced at St Vincent's Hospital in December 2010. Patients eligible for AHSCT had an Expanded Disability Status Scale (EDSS) of 2.0-7, had failed two prior disease-modifying therapies and displayed evidence of ongoing disease activity manifesting as clinical relapses and/or new MRI lesions in the year prior to AHSCT. CD34+ mobilisation with cyclophosphamide and G-CSF was performed, followed by conditioning with a BEAM (carmustine, etoposide, cytarabine, melphalan) + ATG (antithymocyte globulin) chemotherapeutic regimen. Patients underwent clinical assessment and peripheral blood collection for tissue banking at 3, 6, 12 months and yearly to 5 years. Gadolinium enhanced MRI was performed at 6, 12 months and yearly to 5 years. The primary outcomes were event-free survival and overall survival. Event free survival (EFS) was defined as no clinical or radiological relapses and no evidence of disability progression (by EDSS). Polychromic multi-parameter flow cytometry was performed for evaluation of post-transplant immune reconstitution.Results: Forty patients (26 with RRMS and 14 with SPMS) completed AHSCT, with a median follow-up of 24 months (range 3 to 63 months). Median EDSS prior to AHSCT was 6, with 17/40 having an EDSS >6, indicating a significant burden of neurologic disability. Patients were heavily pre-treated with immunosuppressive drugs (DMTs). Fifty-six percent of patients failed >4 disease modifying therapies prior to AHSCT with 2/3 having failed high efficacy treatment with Natalizumab (alpha-4 integrin inhibitor).Progression-free survival, clinical relapse-free survival (RFS), and MRI activity-free survival for the cohort were 80%, 90% and 95% respectively. Event free survival in the RRMS cohort was 90%. Sustained improvement in neurologic function by EDSS was seen in 15/40 (37.5%) of patients; 11 (42.3%) RRMS patients and 4 (28.6%) SPMS patients. MS quality of life score (MSQOL) - physical improved by 14.4 points (p=0.004) and MSQOL - mental improved by 10.3 points (p=0.08). Treatment related mortality was 0%. Adverse effects due to AHSCT were consistent with expected toxicities. One patient required admission to the intensive care unit in the post-transplant period due to serum sickness. There were no significant late neurologic adverse effects noted and no recorded cases of progressive multifocal leukoencephalopathy noted.Conclusion: The relapse-free survival (RFS) in our treatment refractory MS cohort undergoing AHSCT is significantly higher compared to RFS rates in MS patients treated with high-efficacy immunosuppressive therapies. Patients undergoing AHSCT at our institution had comparable rates of EFS to other recent prospective, single centre trials of AHSCT in spite of having higher baseline EDSS, greater evidence of pre-AHSCT disease activity, more heavily pre-treated (Burt et al. 2015, Atkins et al 2016) and use of a less aggressive conditioning regimen (Atkins et al. 2016). In summary, results of this phase II study suggest that AHSCT is effective in inducing sustained remission in the majority of aggressive RRMS and SPMS patients who failed multiple DMTs. DisclosuresNo relevant conflicts of interest to declare.

Inflammation as a Possible Trigger for Mitoxantrone-Induced Cardiotoxicity: An In Vivo Study in Adult and Infant Mice.

Mitoxantrone (MTX) is a pharmaceutical drug used in the treatment of several cancers and refractory multiple sclerosis (MS). Despite its therapeutic value, adverse effects may be severe, namely the frequently reported cardiotoxicity, whose mechanisms need further research. This work aimed to assess if inflammation or oxidative stress-related pathways participate in the cardiotoxicity of MTX, using the mouse as an animal model, at two different age periods (infant or adult mice) using two therapeutic relevant cumulative doses. Histopathology findings showed that MTX caused higher cardiac toxicity in adults. In MTX-treated adults, at the highest dose, noradrenaline cardiac levels decreased, whereas at the lowest cumulative dose, protein carbonylation increased and the expression of nuclear factor kappa B (NF-κB) p65 subunit and of M1 macrophage marker increased. Moreover, MTX-treated adult mice had enhanced expression of NF-κB p52 and tumour necrosis factor (TNF-α), while decreasing interleukin-6 (IL-6). Moreover, while catalase expression significantly increased in both adult and infant mice treated with the lowest MTX cumulative dose, the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glutathione peroxidase only significantly increased in infant animals. Nevertheless, the ratio of GAPDH to ATP synthase subunit beta decreased in adult animals. In conclusion, clinically relevant doses of MTX caused dissimilar responses in adult and infant mice, being that inflammation may be an important trigger to MTX-induced cardiotoxicity.

Stem Cell Therapy as a Treatment for Autoimmune Disease-Updates in Lupus, Scleroderma, and Multiple Sclerosis.

Evidence for hematopoietic stem cell transplantation (HCT) in autoimmune disease has been building since the 1990s; however, many clinicians may not yet be aware of its applications to autoimmune disease. We review the basic tenets of HCT and evidence for autologous HCT in multiple sclerosis (MS), systemic sclerosis (SSc), and lupus with an emphasis on recent advanced phase trials. In MS, the phase 3 randomized MIST trial and the phase 2 randomized ASTIMS trial demonstrated the efficacy of autologous HCT in refractory MS over disease-modifying therapies and mitoxantrone, respectively. In SSc, the phase 3 randomized ASTIS trial and the phase 2 randomized SCOT trial demonstrated the efficacy of autologous HCT in advanced SSc compared to cyclophosphamide. The evidence for HCT in autoimmune diseases continues to grow, particularly in MS and SSc. In lupus, large, comparative trials are still needed. Across autoimmune diseases, questions that still remain to be answered include optimizing patient selection to limit TRM, the appropriate use of MAC, and the necessity for graft manipulation. Furthermore, collaboration between disease-specific and transplant physicians is imperative to expand the appropriate use of HCT in routine clinical practice.

Therapeutic plasma exchange in steroid-refractory multiple sclerosis relapses. A retrospective two-center study.

Background:Therapeutic plasma exchange (TPE) is frequently used in glucocorticosteroid (GCS)-refractory multiple sclerosis (MS) relapses. Data regarding predictors of treatment response are scarce. The objective of this study was to analyze predictive factors for response to TPE in GCS-refractory MS patients.Methods:A total of 118 MS patients in two tertiary MS centers were analyzed. Primary outcome was TPE response defined as marked, mild, or no improvement. Secondary outcome was change in expanded disability status scale (ΔEDSS). ΔEDSS and relapse activity within 6 months after TPE were studied.Results:Marked or mild improvement was observed in 78.8% of patients. ΔEDSS correlated significantly inversely with time from relapse to start of TPE (τ = –0.239, p = 0.001), age (τ = 0.182, p = 0.009) and disease duration (τ = –0.167, p = 0.017). In multivariate analysis, TPE response was predicted by diagnosis of relapsing MS [odds ratio (OR): 3.1], gadolinum-enhancement on magnetic resonance imaging (OR 3.2), age (OR 0.5 per 5 years older) and time from relapse onset to TPE (OR 0.7 per 7 days longer).Conclusion:Patients with longer disease duration and higher EDSS pre and post-TPE were more likely to show further disability progression or relapses within 6 months after TPE. No sustained effects were observed during the follow-up period.

Mobilized Multipotent Hematopoietic Progenitors Stabilize and Expand Regulatory T Cells to Protect Against Autoimmune Encephalomyelitis.

Achieving immunoregulation via in vivo expansion of Foxp3+ regulatory CD4+ T cells (Treg) remains challenging. We have shown that mobilization confers to multipotent hematopoietic progenitors (MPPs) the capacity to enhance Treg proliferation. Transcriptomic analysis of Tregs co-cultured with MPPs revealed enhanced expression of genes stabilizing the suppressive function of Tregs as well as the activation of IL-1β–driven pathways. Adoptive transfer of only 25,000 MPPs effectively reduced the development of experimental autoimmune encephalomyelitis (EAE), a pre-clinical model for multiple sclerosis (MS). Production of the pathogenic cytokines IL-17 and GM-CSF by spinal cord-derived CD4+ T-cells in MPP-protected recipients was reduced while Treg expansion was enhanced. Treg depletion once protection by MPPs was established, triggered disease relapse to the same level as in EAE mice without MPP injection. The key role of IL-1β was further confirmed in vivo by the lack of protection against EAE in recipients of IL-1β–deficient MPPs. Mobilized MPPs may thus be worth considering for cell therapy of MS either per se or for enrichment of HSC grafts in autologous bone marrow transplantation already implemented in patients with severe refractory multiple sclerosis.

A Novel Targeted Approach to Achieve Immune System Reset: CD45-Targeted Antibody Drug Conjugates Enable Autologous HSCT and Ameliorate Disease in Preclinical Autoimmune Disease Models

Resetting the immune system through autologous hematopoietic stem cell transplant (autoHSCT) is a highly effective treatment in patients with autoimmune diseases (AID). AutoHSCT achieved long-term remission in patients with relapsed refractory and secondary progressive multiple sclerosis (Muraro 2017), superior to their previous standard of care (Burt 2019). AutoHSCT in scleroderma patients achieved superior outcomes in two randomized studies (Tyndall 2014, Sullivan 2018). These impressive results are achieved by both eradication of autoreactive immune effector cells and re-establishment of a self-tolerant immune system, i.e., immune system reset. However, only a fraction of eligible patients undergo autoHSCT, in part due to toxicity associated with current conditioning regimens that remove the disease-causing cells. To enable more patients to benefit from immune reset without debilitating chemotherapy, we generated novel anti-human CD45 ADCs that cross react with NHP and evaluated these for the ability to deplete hematopoietic cells in vitro and in vivo (Fig.1). In vitro the CD45-ADC efficiently killed human CD34+ progenitors and peripheral CD3+ T cells from both healthy donors and MS patients. In vivo in humanized NSG mice, single doses of the CD45-ADCs were well-tolerated and led to depletion of human hematopoietic cells in BM (Fig. 1A) and periphery. In NHPs, single doses of CD45-ADCs were well tolerated and depleted BM HSCs and peripheral lymphocytes (Fig.1B). CD45-ADC treatment of hNSGs with sclerodermatous xenoGVHD resulted in resolution of symptoms (Fig. 1C). To model the complete immune reset approach in mouse models of AID, we generated a tool anti-mouse CD45 ADC. A single-dose enabled full myeloablation (>99% depletion of LT-HSCs) and complete donor chimerism with congenic HSCT (>90% chimerism at 16 weeks). In an adoptive transfer model of type I diabetes, treatment with a single dose of CD45-ADC and congenic HSCT led to disease prevention. In a murine model of MS EAE, a single dose of the CD45-ADC followed by congenic HSCT enabled full donor chimerism; treatment prior to disease onset significantly delayed disease onset and reduced disease severity; treatment after disease onset also halted progression of symptoms. These data demonstrate that CD45-ADC conditioning followed by congenic HSCT is sufficient for full myeloablation and immune reset. Experiments are ongoing, and evaluation of this ADC in murine models of diabetes and arthritis will be presented. These results indicate that targeted immune depletion with a single dose of CD45-ADC may be sufficient to enable auto-HSCT and immune reset in multiple AID indications. Targeted conditioning with CD45-ADC may enable more patients to benefit from immune reset through removal of pathogenic cells and autoHSCT without the morbidity and mortality associated with current chemotherapeutic conditioning.

A Scoping Review on Clinical Trials of Pain Reduction With Cannabis Administration in Adults.

Indications of cannabis use are numerous although the indication to relief pain remains a major research interest and clinical application. Studies investigating the effect of herbal cannabis and cannabis-based medicine on neuropathic, non-neuropathic pain, acute pain and experimentally induced pain were reviewed. A search was performed in PubMed and Cochrane library for articles published in English between January 1, 2000 and May 8, 2020. The search terms used were related to cannabis and pain in adults. We identified 34 studies, of which 30 were randomized controlled clinical trials (RCTs). Varying effects were identified from the RCTs, and as expected more promising effects from non-RCTs. Cannabis-based medications were found most effective as an adjuvant therapy in refractory multiple sclerosis, and weak evidence was found to support the treatment of cancer pain especially in advanced stages. Chronic rheumatic pain showed promising results. Adverse events of cannabis-based treatment were found to be more frequent with tetrahydrocannabinol herbal strains compared to other cannabis-derived products.

Comparing Plasma Exchange to Escalated Methyl Prednisolone in Refractory Multiple Sclerosis Relapses.

Intravenous methyl prednisolone (IVMPS) represents the standard of care for multiple sclerosis (MS) relapses, but fail to improve symptoms in one quarter of patients. In this regard, apart from extending steroid treatment to a higher dose, therapeutic plasma exchange (TPE) has been recognized as a treatment option. The aim of this retrospective, monocentric study was to investigate the efficacy of TPE versus escalated dosages of IVMPS in refractory MS relapses. An in-depth medical chart review was performed to identify patients from local databases. Relapse recovery was stratified as “good/full”, “average” and “worst/no” according to function score development. In total, 145 patients were analyzed. Good/average/worst recovery at discharge was observed in 60.9%/32.6%/6.5% of TPE versus 15.2%/14.1%/70.7% of IVMPS patients, respectively. A total of 53.5% of IVMPS patients received TPE as rescue treatment and 54.8% then responded satisfactorily. The multivariable odds ratio (OR) for worst/no recovery was 39.01 (95%–CI: 10.41–146.18; p ≤ 0.001), favoring administration of TPE as first escalation treatment. The effects were sustained at three-month follow-ups, as OR for further deterioration was 6.48 (95%–CI: 2.48–16.89; p ≤ 0.001), favoring TPE. In conclusion, TPE was superior over IVMPS in the amelioration of relapse symptoms at discharge and follow-up. This study provides class IV evidence supporting the administration of TPE as the first escalation treatment to steroid-refractory MS relapses.

A Novel Targeted Approach to Achieve Immune System Reset: CD45-Targeted Antibody Drug Conjugates Enable Autologous HSCT, Ameliorate Disease in Autoimmune Models, Potently Kill Human Immune Cells from Normal Donors and MS Patients, and Achieve Immune Depletion in Non-Human Primates (NHP)

Resetting the immune system through autologous hematopoietic stem cell transplant (autoHSCT) is a highly effective treatment in selected patients with autoimmune diseases. AutoHSCT can induce long-term remission (up to 15 years) with 70-80% progression free survival in patients with relapsed refractory and secondary progressive multiple sclerosis (Muraro 2017) that is superior to standard of care agents in a randomized study (Burt 2019). Likewise, use of autoHSCT in scleroderma patients achieved superior outcomes in two randomized studies (Tyndall 2014, Sullivan 2018). These impressive results are achieved by a combination of the eradication of autoreactive immune effector cells and re-establishment of a self-tolerant immune system, i.e., immune system reset. However, only a small fraction of eligible patients undergo autoHSCT, in part due to toxicity associated with current conditioning protocols. To address these issues, we are developing antibody drug conjugates (ADCs) that selectively target CD45 to eradicate autoimmune cells and enable autoHSCT as a potential one-time curative treatment for patients with autoimmune disease. To model this approach in mice, we generated an anti-mouse CD45 ADC that was evaluated for the ability to condition recipients in a murine congenic transplant model following a single myeloablative dose. This ADC was further evaluated for its ability to eliminate pathogenic host-reactive cells and enable immune reset in recipients in multiple murine models of autoimmune disease, including MOG-induced experimental autoimmune encephalitis (EAE), proteoglycan-induced arthritis (PGIA), and sclerodermatous graft-vs-host disease (scGVHD). A single-dose of tool anti-mouse CD45-ADC at 3 mg/kg achieved full myeloablation in recipient mice (>99% depletion of LT-HSCs (Lin-Kit+Sca-1+CD150+CD48-). Transplanted mice achieved full engraftment with congenic BMT (>90% chimerism at 16 weeks). In EAE, conditioning with a non-myeloablative dose of the CD45-ADC followed by congenic transplant prior to disease onset significantly delayed disease onset and reduced disease severity (onset at 21 days, peak disease score 2.1 for with 1 mg/kg CD45-ADC; onset at 42 days, peak disease score 0.75 for 3 mg/kg CD45-ADC + BMT; onset at 11 days with peak disease score 3.1 for vehicle-treated)[Figure 1]. In active EAE, treatment with 3 mg/kg of CD45-ADC on day 10 or 13 followed by congenic transplant halted progression of disease activity (no increase from disease score at time of treatment; peak disease scores of 0.75 and 2.3, respectively). The effect observed with CD45-ADC treatment at day 13 with congenic transplant was comparable to that achieved by treatment with a clinically validated standard of care, FTY-720 (approved S1P1 antagonist equivalent to Gilenya) at day 13 which also halted disease at a peak score of 2.3. Disease control in this study compared favorably to a prior study where mice were treated with 9 Gy TBI + congenic BMT at day 9. These data show that CD45-ADC conditioning followed by congenic transplant is effective at immune reset and shows comparable efficacy to clinically validated therapies. Evaluation of this ADC in additional autoimmune models of arthritis and scleroderma are ongoing and will be presented. To translate these encouraging pre-clinical data, we generated novel anti-human CD45 ADCs that cross react with nonhuman primates (NHP) and evaluated these for the ability to deplete hematopoietic and immune cells in vitro and in vivo in humanized NSG (hNSG) mice. The CD45-ADC showed efficient killing of human BM CD34+ (EC50 2.44 x 10-9 M) and peripheral CD3+ cells from normal donor (EC50 7.6 x10-10 M) and MS patients (EC50 1.5 x 10-10 M). In vivo in hNSG, single doses of the CD45-ADCs were well-tolerated and led to substantial (>95%) depletion of human cells. In NHPs, single doses of CD45-ADCs were well tolerated and achieved >90% peripheral lymphocyte depletion and >80% depletion of HSCs. Dose escalation studies are continuing and will be reported. These results suggest that targeted immune depletion with a single treatment of CD45-ADC may be sufficient for auto-HSCT and allow immune reset and re-establishment of immune tolerance. Targeted CD45-ADCs may represent a safer and better tolerated approach for conditioning patients prior to immune reset through autoHSCT and may significantly reduce the side effects associated with current conditioning. Disclosures Gillard: Magenta Therapeutics: Employment, Equity Ownership. Proctor:Magenta Therapeutics: Employment, Equity Ownership. Brooks:Magenta Therapeutics: Employment, Equity Ownership. Lamothe:Magenta Therapeutics: Employment, Equity Ownership. Hyzy:Magenta Therapeutics: Employment, Equity Ownership. Mikse:Magenta Therapeutics: Employment, Equity Ownership. McDonough:Magenta Therapeutics: Employment, Equity Ownership. Palchaudhuri:Magenta Therapeutics: Employment, Equity Ownership. Bhat:Magenta Therapeutics: Employment, Equity Ownership. Sarma:Magenta Therapeutics: Employment, Equity Ownership. Bhattarai:Magenta Therapeutics: Employment, Equity Ownership. Sawant:Magenta Therapeutics: Employment, Equity Ownership. Pearse:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Mcdonough:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.

FTY720 induces non-canonical phosphatidylserine externalization and cell death in acute myeloid leukemia

FTY720 (fingolimod) is a FDA-approved sphingosine analog that is phosphorylated in vivo to modulate sphingosine-1-phosphate receptor (S1PR) signaling for immunosuppression in patients with refractory multiple sclerosis. FTY720 also exhibits promising anticancer efficacy in several preclinical models. While FTY720-induced cytotoxicity is not due to S1PR signaling, the mechanism remains unclear and is reported to occur through various cell death pathways. Here, we performed a systematic, mechanistic study of FTY720-induced cell death in acute myeloid leukemia (AML). We found that FTY720 induced cell death in a panel of genetically diverse AML cell lines that was accompanied by rapid phosphatidylserine (PS) externalization. Importantly, FTY720-induced PS exposure was not due to any direct effects on plasma membrane integrity and was independent of canonical signaling by regulated cell death pathways known to activate lipid flip-flop, including caspase-dependent apoptosis/pyroptosis, necroptosis, ferroptosis, and reactive oxygen species-mediated cell death. Notably, PS exposure required cellular vacuolization induced by defects in endocytic trafficking and was suppressed by the inhibition of PP2A and shedding of Annexin V-positive subcellular particles. Collectively, our studies reveal a non-canonical pathway underlying PS externalization and cell death in AML to provide mechanistic insight into the antitumor properties of FTY720.

Longitudinal follow-up of dual-lead thalamic deep brain stimulation for patients with treatment refractory multiple sclerosis tremor (P4.8-044)

Longitudinal follow-up of dual-lead thalamic deep brain stimulation for patients with treatment refractory multiple sclerosis tremor (P4.8-044)

Late Cardiotoxicity in MS Patients Treated with Mitoxantrone.

Context:Mitoxantrone (MTX) is an antracyclin drug that is used for treatment of patients with chronic refractory multiple sclerosis (MS). Congestive heart failure (CHF) is a rare complication of this drug that may occur early, during therapy, or late, months or years after termination of therapy.Aims:The aim of this study is to evaluate the long-term adverse effect of MTX on cardiac function.Methods:The study involved 49 MS patients on MTX therapy because of their disease was refractory to other treatments (18 men and 31 women). They were treated in two canters related to Esfahan University of Medical Sciences. The mean age was 34.65 ± 9.56 years. Systolic and diastolic left ventricular (LV) functions were measured by echocardiography. The baseline echocardiographic data were collected from patients' file. Echocardiography was repeated by a single cardiologist in 2016.Results:After MTX therapy, one patient's ejection fraction (EF) reduced below 50% (2%). In spite of their normal diastolic function before therapy, two patients developed diastolic dysfunction (4%). Nonparametric binominal analysis reveals that MTX therapy increased the probability of developing systolic dysfunction, early or late P < 001.Conclusions:MS patients treated with MTX are at increased risk of developing early and late-LV dysfunction, so all patients on MTX therapy must be periodically evaluated for these late complications.

Prospective phase II clinical trial of autologous haematopoietic stem cell transplant for treatment refractory multiple sclerosis

BackgroundAutologous haematopoietic stem cell transplantation (AHSCT) has been explored as a therapeutic intervention in multiple sclerosis (MS) over the last two decades; however, prospective clinical trials of the most common...

Hematopoietic Stem Cell Transplantation for CNS Autoimmune Disorders for Adults and Children: Long-Term Outcomes - Experience of the Russian Federation

Rationale. More than 70 000 of patients registered with multiple sclerosis (MS) registered in Russia annually. Some of adults and children with CNS autoimmune disorder (AD) require hematopoietic stem cell transplantation (HSCT). We analyzed long-term outcomes and late effects in adults and children with MS and neuromyelitis optica (NMO) after HSCT treated in three Russian centers.Patients and Methods. Sixteen children were treated in the Russian Children's Research Hospital in collaboration with Dmitry Rogachev Center: MS - 13, NMO - 3. MS: female (F) - 9, male (M)- 4; NMO: all females. MS median age - 16,8±1,6 y.o., median Expanded Disability Status Scale (EDSS) 6,16±0,2. NMO pts median age - 12,7±1,4 y.o. All patients had severe refractory disease. MS children received Cyclophosphomide and horse ATG, NMO - Treosulfan, Fludarabine, Rituximab and horse ATG. Nighty nine MS adults received HSCT in National Pirogov Medical Surgical Center with reduced-intensity BEAM-like conditioning regimen in mean age-35 y.o.; M:F=39:60; median EDSS = 3.5; disease status - 43 relapsing/remitting MS, 56 progressive MS. Thirty-two MS adult patients were transplanted in Raisa Gorbacheva Research Institute during 2 periods of time: 25 patients in 2000 - 2010 (mean age - 34,4 y.o., M:F=12:13, mean EDSS=4,3) with conditioning regimen BEAM and horse ATG and in 2018 (mean age - 36 y.o., M:F=3:4, mean EDSS=4.5) with conditioning regimen based on Cyclophosphomide and horse ATG.Results. Rapid improvement of EDSS registered in children - EDSS decreasing on 3,1±0,3 during first 60 days. Median follow-up - 52,1 ± 2,3 months (12-86 months). Two MS patients relapsed (clinical and MRI). Almost all NMO patients stopped the progression and improved neurologically (clinical and MRI) except 1 pt - died due to refractory ADV-infection. Median follow-up - 24,2±4,5 months (1- 62 months). MS patients late effects cardio-vascular - 5 pts, endocrine - 3 pts (all females). NMO patients late effects: cardio-vascular - 2 pts., late immune reconstitution - 1 pt. In Pirogov Medical Surgical Center group at 6 months post-transplant, neurological improvement or stabilization was observed in all the patients except one. Cumulative incidence of disease progression was 16.7 % at 8 years after HSCT. Sixty-four patients who did not progress during the first 3 years post-transplant and were monitored for more than 3 years were included in long-term outcome analysis. At the median long-term follow-up of 62 months, 47 % of patients improved by at least 0.5 points on the EDSS as compared to baseline and exhibited improvement during the entire period of follow-up; 45 % of patients were stable. In Raisa Gorbacheva Research Institute 50% of patients (group transplanted in 2000 - 2010) relapsed, group transplanted in 2018 - 4 patients were improved on therapy and 3 - stabilized.Conclusions. HSCT is used both for children and adults in Russia. It is successful approach for refractory MS and pediatric NMO treatment. In-time HSCT can significantly improve the outcome. Late effects can be found in these patients, so it's important to find it and give adequate rehabilitation. Thus, the risk/benefit ratio of HSCT in our population of these patients are very favorable. DisclosuresNo relevant conflicts of interest to declare.