Lymphopenia is Not the Primary Therapeutic Mechanism of Diroximel Fumarate in Relapsing-Remitting Multiple Sclerosis: Subgroup Analyses of the EVOLVE-MS-1 Study.

INTRODUCTION: In EVOLVE-MS-1 (NCT02634307), mean absolute lymphocyte count (ALC) on diroximel fumarate (DRF) declined from baseline by approximately 28% in year 1, then stabilized, similar to ALC decline observed with dimethyl fumarate (DMF). Prior studies reported that clinical efficacy of DMF was not substantially different in patients with and without lymphopenia. METHODS: EVOLVE-MS-1-an open-label, 96-week, phase 3 study-assessed DRF safety and exploratory efficacy in patients with relapsing-remitting multiple sclerosis. This study analyzes efficacy-related outcomes comparing (1) patients with lymphopenia (≥ 1 ALC below lower limit of normal [LLN]) and without (all ALCs ≥ LLN); (2) across quartiles stratified by week 96 ALC decline from baseline: Q1 (≥ 47% decline); Q2 (30% to < 47% decline); Q3 (12% to < 30% decline); Q4 (< 12% decline). RESULTS: Baseline characteristics were similar between patients without (n = 593) and with lymphopenia (n = 452). At week 96, adjusted annualized relapse rate (ARR; 95% confidence interval) was 0.14 (0.11-0.17) without lymphopenia and 0.12 (0.09-0.15) with lymphopenia. Estimated proportions with 12-week confirmed disability progression (CDP12) at week 96 were 10.2% without and 9.3% with lymphopenia. When stratified by quartiles (Q1-Q4), ARR at week 96 was 0.11 (Q1), 0.09 (Q2), 0.13 (Q3), and 0.17 (Q4). Estimated proportions with CDP12 at week 96 were 9.6% (Q1), 10.2% (Q2), 5.7% (Q3), and 10.9% (Q4). At week 96, no evidence of disease activity was achieved by 47.2% (Q1), 47.8% (Q2), 45.4% (Q3), and 37.3% (Q4) of patients. CONCLUSION: In DRF-treated patients in EVOLVE-MS-1, clinical and radiological measurements indicated reduced disease activity regardless of lymphopenia or magnitude of ALC decline from baseline; however, patients who had greater ALC declines appeared to have numerically lower ARR and higher proportions free from relapses and gadolinium-enhancing lesions compared with those with smallest decline. This supports prior evidence that, while lymphopenia may contribute to fumarate efficacy outcomes, it is not the primary mechanism of action. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02634307.

Real-world treatment preferences among health care providers in the United States in selecting disease modifying therapies for patients with multiple sclerosis: a discrete choice experiment.

AIMS: Health care providers (HCPs) treating multiple sclerosis (MS) in clinical practice have numerous disease-modifying therapies (DMTs) to consider when evaluating treatment options. This study assessed the treatment preferences of HCPs in the United States, both direct (explicit) and derived (explicit and implicit), when selecting MS DMTs based on clinical and logistical treatment attributes. MATERIALS AND METHODS: A 45-minute web-enabled questionnaire was administered to HCPs who manage patients with MS to assess the importance of treatment attributes. HCPs were recruited through an online panel. This study examined treatment attributes relevant to treatment decisions in MS, with a focus on the burden to HCPs and their staff, as well as HCP attitudes toward various aspects of MS care such as diagnosis, treatment prioritization, and ease of initiating or switching DMTs. The study also employed a discrete choice experiment (DCE) to assess direct and derived treatment preferences. RESULTS: The study recruited 145 HCPs. Direct assessments (a score of greater than 7.0 was considered important) suggested that safety (mean importance rating = 7.8/9) and relative risk reduction in relapses (7.6/9) and disability progression (7.5/9) were most important when selecting DMTs. In contrast, derived importance from the DCE (higher points corresponding to greater importance) suggested that logistical attributes such as dose frequency (mean relative attribute importance = 17.5%), dose titration (10.3%), formulation (9.4%), and volume of calls (9.1%) were important considerations, along with efficacy (16.5%), safety (9.8%), and gastrointestinal tolerability (9.4%). LIMITATIONS: This study may have been subject to selection bias due to the application of eligibility criteria, the convenient sampling recruitment methodology, and recruitment of HCPs with internet access. CONCLUSION: In the direct assessment, clinical attributes were chosen as the most important treatment attributes by HCPs. However, in the DCE, derived treatment decisions rated logistical attributes as also being as important in treatment choice.

In this study, researchers aimed to understand what multiple sclerosis (MS) neurologists, nurse practitioners, and physician assistants think is most important when choosing medicines for their patients. They surveyed 145 health care providers (HCPs) in the United States for this study. The HCPs reported that safety and reducing the risk of relapses and disability were most important when selecting medicines. Additionally, the researchers used a method called a discrete choice experiment to determine the relative importance of medication characteristics to HCPs. They found that additional factors, such as how often the medicine needs to be taken, how it is given, and how easy it is to use, were also very important. The study may not represent the opinions of all HCPs due to the number of participants and participation criteria.

Diroximel fumarate in patients with relapsing-remitting multiple sclerosis: Final safety and efficacy results from the phase 3 EVOLVE-MS-1 study.

BACKGROUND: Diroximel fumarate (DRF) is approved for adults with relapsing-remitting multiple sclerosis (RRMS) in Europe and for relapsing forms of MS in the United States. DRF and dimethyl fumarate (DMF) yield bioequivalent exposure of the active metabolite monomethyl fumarate. Prior studies indicated fewer gastrointestinal (GI)-related adverse events (AEs) with DRF compared with DMF. OBJECTIVE: To report final outcomes from EVOLVE-MS-1. METHODS: EVOLVE-MS-1 was an open-label, 96-week, phase 3 study assessing DRF safety, tolerability, and efficacy in patients with RRMS. The primary endpoint was safety and tolerability; efficacy endpoints were exploratory. RESULTS: Overall, 75.7% (800/1057) of patients completed the study; median exposure was 1.8 (range: 0.0-2.0) years. AEs occurred in 938 (88.7%) patients, mostly of mild (28.9%) or moderate (50.3%) severity. DRF was discontinued due to AEs in 85 (8.0%) patients, with < 2% discontinuing due to GI or flushing/flushing-related AEs. At Week 96, mean number of gadolinium-enhancing lesions was significantly reduced from baseline (72.7%; p < 0.0001); adjusted annualized relapse rate was 0.13 (95% confidence interval: 0.11-0.15). CONCLUSION: DRF was generally well tolerated over 2 years, with few discontinuations due to AEs; radiological measures indicated decreased disease activity from baseline. These outcomes support DRF as a treatment option in patients with RRMS.

Efficacy of Dimethyl Fumarate in Young Adults with Relapsing-Remitting Multiple Sclerosis: Analysis of the DEFINE, CONFIRM, and ENDORSE Studies.

INTRODUCTION: Dimethyl fumarate (DMF) showed favorable benefit-risk in patients with relapsing-remitting multiple sclerosis (MS) in phase 3 DEFINE and CONFIRM trials and in the ENDORSE extension study. Disease activity can differ in younger patients with MS compared with the overall population. METHODS: Randomized patients received DMF 240 mg twice daily or placebo (PBO; years 0-2 DEFINE/CONFIRM), then DMF (years 3-10; continuous DMF/DMF or PBO/DMF; ENDORSE); maximum follow-up (combined studies) was 13 years. This integrated post hoc analysis evaluated safety and efficacy of DMF in a subgroup of young adults aged 18-29 years. RESULTS: Of 1736 patients enrolled in ENDORSE, 125 were young adults, 86 treated continuously with DMF (DMF/DMF) and 39 received delayed DMF (PBO/DMF) in DEFINE/CONFIRM. Most (n = 116 [93%]) young adults completed DMF treatment in DEFINE/CONFIRM. Median (range) follow-up time in ENDORSE was 6.5 (2.0-10.0) years. Young adults entering ENDORSE who had been treated with DMF in DEFINE/CONFIRM had a model-based Annualized Relapse Rate (ARR; 95% CI) of 0.24 (0.16-0.35) vs. 0.56 (0.35-0.88) in PBO patients. ARR remained low in ENDORSE: 0.07 (0.01-0.47) at years 9-10 (DMF/DMF group). At year 10 of ENDORSE, EDSS scores were low in young adults: DMF/DMF, 1.9 (1.4); PBO/DMF, 2.4 (1.6). At ~ 7 years, the proportion of young adults with no confirmed disability progresion was 81% for DMF/DMF and 72% for PBO/DMF. Patient-reported outcomes (PROs) (SF-36 and EQ-5D) generally remained stable during ENDORSE. The most common adverse events (AEs) in young adults during ENDORSE were MS relapse (n = 53 [42%]). Most AEs were mild (n = 20 [23.3%], n = 7 [17.9%]) to moderate (n = 45 [52.3%], n = 23 [59.0%]) in the DMF/DMF and PBO/DMF groups, respectively. The most common serious AE (SAE) was MS relapse (n = 19 [15%]). CONCLUSION: The data support a favorable benefit-risk profile of DMF in young adults, as evidenced by well-characterized safety, sustained efficacy, and stable PROs. CLINICAL TRIAL INFORMATION: Clinical trials.gov, DEFINE (NCT00420212), CONFIRM (NCT00451451), and ENDORSE (NCT00835770).

Real-World Analysis Affirms the High Persistence and Adherence Observed with Diroximel Fumarate in Patients with Multiple Sclerosis.

INTRODUCTION: Adherence to disease-modifying therapies is key for achieving optimal outcomes in multiple sclerosis (MS). Diroximel fumarate (DRF) is an oral fumarate approved for treatment of relapsing forms of MS. It has the same pharmacologically active metabolite as dimethyl fumarate (DMF) and similar efficacy and safety profiles, but with demonstrated fewer gastrointestinal (GI) related adverse events (AEs). There are limited data characterizing persistence and adherence to DRF in the real world. METHODS: This retrospective analysis of the AcariaHealth Specialty Pharmacy Program included patients with MS initiating DRF from 1 December 2019 to 30 January 2021. This analysis evaluated persistence, measured as proportion of patients remaining on therapy; discontinuation rate due to GI AEs; and adherence measured by proportion of days covered (PDC). RESULTS: Overall, 1143 patients were included; 433 (37.9%) patients had been treated with prior DMF and switched to DRF. Persistence was high in both groups: the estimated proportion of patients remaining on DRF at 16 months was 82.3% [95% confidence internal (CI) 77.2-86.3%], and 90.1% (95% CI 82.2-94.6%) in the DMF to DRF group. Fifty-two (4.5%) patients overall and 15 (3.5%) in the DMF switch subgroup discontinued DRF due to GI AEs. Mean PDC was 90.8% (95% CI 89.2-92.5%), and 85.4% (95% CI 83.3-87.4%) of patients achieved PDC ≥ 80% in the overall population. In the DMF to DRF group, mean PDC was 90.7% (95% CI 88.0-93.5%), and 84.8% (95% CI 81.4-88.1%) of patients achieved PDC ≥ 80%. CONCLUSION: In this analysis of  > 1000 patients treated with DRF in real-world clinical practice, overall persistence at 16 months was high, treatment discontinuation due to GI AEs was low, and patients were highly adherent to therapy. Of 433 patients who switched from DMF to DRF, most (> 90%) were able to tolerate and persist on DRF after switching. Graphical abstract available for this article.

Dimethyl fumarate is associated with lower rates of infection and lower infection-related healthcare costs when compared with ocrelizumab.

BACKGROUND: Infections in people with multiple sclerosis (PwMS) may have a detrimental effect on disease progression, risk of hospitalization, and healthcare resource utilization (HRU). The infection risk and HRU costs may vary between disease-modifying therapies (DMTs); however, the individual risks and differences associated with DMTs are not well characterized. Some DMTs may increase the risk for infections in PwMS; however, previous studies have reported an intact humoral immune response in dimethyl fumarate (DMF)-treated patients. The objective was to compare infection-related HRU and healthcare costs (HCCs) between PwMS treated with DMF or ocrelizumab (OCR). METHODS: Eligible patients were identified from the Optum US claims database between April 2017 and September 2020 (DMF n = 1429; OCR n = 3170). Patients were followed from index date to first occurrence of: (1) end of study, (2) end of insurance eligibility, (3) discontinuation of index DMT, or (4) switch from index DMT to another DMT. Outcomes were annualized rate of infection encounters (defined as infection encounters [n] during follow-up window / days followed [n] × 365); annualized infection-related HCCs (defined as aggregated costs of infection encounters during follow-up window / days followed [n] × 365); location-specific infections, and overall infection-related events. Propensity score matching (PSM) 1:1 method was used; PS was calculated via logistic regression for probability of DMF treatment conditional on demographics and comorbidities. Mean differences (MD) were reported for infection encounter measures. RESULTS: After PSM, DMF and OCR cohorts (n = 1094 in each cohort) were balanced based on baseline characteristics (standardized MD of adjusted baseline characteristics <0.1). Mean (standard deviation) follow-up was 296 (244) days for DMF patients and 297 (243) for OCR patients. DMF patients experienced lower annualized rates of overall infection encounters vs OCR patients (MD -0.51 [95% confidence interval (CI): -0.92 to -0.11], p = 0.01). When stratified by type of infection encounter, DMF patients experienced significantly lower annualized rates of outpatient (MD [95% CI]: -0.44 [-0.80 to -0.08], p = 0.02) and inpatient/hospitalization infection encounters (-0.08 [-0.14 to -0.02], p<0.01) vs OCR patients. A trend towards a shorter duration of infection-related hospitalization in the DMF vs the OCR group was observed (MD [95% CI]: -2.20 [-4.73 to 0.26] days, p = 0.08). The most common infection types in both DMT groups were urinary tract infections, sepsis, and pneumonia. DMF patients experienced lower annualized infection-related HCCs (MD [95% CI]: -$3642 [-$6380 to -$904], p < 0.01) vs OCR patients, which were driven largely by infection-related hospitalization costs (-$3639 [-$6019 to -$1259], p < 0.01). CONCLUSION: DMF-treated patients PS-matched with OCR patients experienced lower annualized rates of infection encounters and lower infection-related HCCs.

Health-Related Quality of Life with Diroximel Fumarate in Patients with Relapsing Forms of Multiple Sclerosis: Findings from Qualitative Research Using Patient Interviews.

INTRODUCTION: Diroximel fumarate (DRF) is an oral fumarate for relapsing multiple sclerosis (MS). Clinical and real-world studies of DRF have demonstrated improved gastrointestinal (GI) tolerability and low (< 1%) GI-related treatment discontinuation versus dimethyl fumarate (DMF) and high rates of treatment adherence. Our aim was to conduct a concept elicitation study to identify treatment-related concepts most meaningful to patients and to evaluate how these concepts shape the patient perspective of DRF. METHODS: In-depth qualitative interviews were conducted with patients from October to December 2020. US adults who had been prescribed DRF through routine clinical care and had taken DRF for ≥ 3 weeks in the past 6 months were eligible to participate. Semi-structured interviews explored patient perceptions on treatment selection and impact. RESULTS: Seventeen patients participated in the study. Mean (SD) age was 49.3 (12.0) years. Sixteen patients reported prior disease-modifying therapy, while 10 (58.8%) had prior DMF. DRF treatment duration ranged from ~ 6 weeks to 10 months. Four key concepts emerged: (1) overall wellness and quality of life, (2) ease of administration, (3) minimal and manageable side effects, and (4) patient optimism due to MS treatments. Mode of administration (82.4%), no/mild side effects (70.6%), convenience over injectable/infusion medications (58.8%), and effectiveness (64.7%) were cited as positive aspects of DRF treatment. Frequent dosing (52.9%) and food requirements (41.2%) were cited as negative attributes; however, 94.1% had no dietary changes since starting treatment. CONCLUSION: The patient perspective is a key aspect when considering a disease-modifying therapy for MS, given the multitude of options currently available. Overall wellness, ease of administration, and minimal and manageable side effects were DRF-related concepts most meaningful to patients on therapy. Acknowledging these patient perceptions in shared decision-making may lead to greater patient adherence and optimal treatment outcomes.

Multiple sclerosis (MS), an immune-related disease, may present with neurological symptoms that come and go. Diroximel fumarate (DRF) is a next-generation oral treatment for MS, which has been shown in clinical trials to have fewer gastrointestinal side effects compared to dimethyl fumarate (DMF), another oral treatment. Patients' perspective can shed light on what they value when choosing a treatment, so we interviewed 17 people with MS about how DRF treatment affects their daily life and work. The study participants (49.3 years old on average) received DRF for ~ 6 weeks to 10 months. Around 5 in 10 people had positive feelings about their current health following treatment with DRF. Most felt there was either improvement or no negative change in quality of life since starting DRF treatment; DRF did not affect their work or daily obligations. Treatment characteristics of DRF that were perceived as most important included ease of administration, minimal and manageable side effects, and the facilitation of overall wellness and quality of life. While the oral dosing of DRF was more convenient than injectable or infusion therapy options, about half of the respondents preferred a less frequent treatment regimen than the twice daily dosing of DRF which needs to be taken with food. However, those who switched to DRF from DMF (or other oral medications for MS) expressed that the transition was smooth. Understanding factors that are important to patients can guide treatment choices and help patients stay on treatment longer and have better MS outcomes.

Efficacy and Safety Outcomes with Diroximel Fumarate After Switching from Prior Therapies or Continuing on DRF: Results from the Phase 3 EVOLVE-MS-1 Study.

INTRODUCTION: Diroximel fumarate (DRF) is an oral fumarate for relapsing multiple sclerosis (MS) with the same active metabolite as dimethyl fumarate (DMF). DRF has a safety/efficacy profile similar to DMF but with improved gastrointestinal (GI) tolerability and low (< 1%) treatment discontinuation due to GI adverse events (AEs). Efficacy and safety outcomes in patients who switched to DRF from other disease-modifying therapies (DMTs) have not been evaluated. METHODS: EVOLVE-MS-1 is an ongoing, 2-year, open-label, phase 3 study of DRF in adults with relapsing-remitting MS. Patients either entered as newly enrolled to DRF trials, or from the 5-week, randomized, head-to-head, phase 3 EVOLVE-MS-2 study of DRF and DMF. This analysis evaluated safety and GI tolerability in patients continuing on DRF (DRF-rollover) or switching from DMF (DMF-rollover) following EVOLVE-MS-2. Safety and efficacy were evaluated in a subset of newly enrolled patients who had received prior glatiramer acetate (GA; GA/DRF) or interferons (IFN; IFN/DRF) as their most recent DMT, prior to switching to DRF in EVOLVE-MS-1. RESULTS: As of September 1, 2020, 1057 patients were enrolled in EVOLVE-MS-1, including 166, 182, 239, and 225 patients in the GA/DRF, IFN/DRF, DRF-rollover, and DMF-rollover groups, respectively. Treatment discontinuation due to GI AEs was < 1% in all groups. GA/DRF and IFN/DRF patients experienced improvements from baseline in clinical and radiological efficacy outcomes, including significantly reduced annualized relapse rates. Rollover patients had low rates of new or recurrent GI AEs (DRF-rollover, 26.8%/4.2%; DMF-rollover, 27.1%/4.9%). CONCLUSION: After 2 years of DRF exposure, patients with prior GA, IFN, or fumarate treatment had safety outcomes consistent with previous fumarate studies. Efficacy in patients with prior GA or IFN treatment was consistent with previous fumarate studies. The data suggest that transition to DRF from GA, IFN, or DMF is a reasonable treatment strategy, with low rates of discontinuation due to GI AEs. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02634307). INFOGRAPHIC.

Multiple Sclerosis Patients Treated With Diroximel Fumarate in the Real-World Setting Have High Rates of Persistence and Adherence.

INTRODUCTION: Persistence to multiple sclerosis (MS) disease-modifying therapy is fundamental for maximal treatment outcomes. Diroximel fumarate (DRF) is approved in the USA for relapsing MS. Following oral administration, DRF is metabolized to monomethyl fumarate, the active metabolite of dimethyl fumarate (DMF). DRF showed clinically significant improvements in gastrointestinal (GI) tolerability versus DMF in a head-to-head clinical trial; however, real-world persistence/adherence has not been assessed. We evaluated persistence/adherence in DRF-treated patients in a real-world clinical practice. METHODS: This retrospective analysis of the AcariaHealth Specialty Pharmacy Program included patients initiating DRF from 4 December 2019 through 3 April 2020 and followed until data extraction (31 August 2020). Exclusion criteria included undetermined treatment status (e.g., DRF prescription transfer to a different pharmacy). Endpoints included persistence (overall proportion of patients remaining on DRF), discontinuation rate due to GI adverse events (AEs), and adherence (proportion of days covered [PDC]). GI AEs included GI-related AEs occurring at any time, or any unknown AE without details about the nature of the event if the unknown AE occurred ≤ 90 days after DRF initiation. RESULTS: Overall, 160 patients with MS were included. Median (range) patient age was 51 (20-79) years, 80.6% (129/160) of patients were female, and 16.3% (26/160) had prior DMF treatment. Median (range) treatment duration was 7.6 (0.1-10.4) months. Estimated proportion of patients remaining persistent on DRF treatment at 8 months was 88.6% (95% confidence interval [CI] 82.5-2.7). Overall, 3.8% (6/160) of patients discontinued due to GI AEs. Mean PDC was 91.4% (95% CI 89.1-93.7). In a DMF-to-DRF switch subgroup, 92.3% (24/26) remained persistent on DRF, and 3.8% (1/26) discontinued DRF due to GI AEs. CONCLUSION: This real-world analysis of DRF-treated patients showed high overall persistence, low discontinuation rate due to GI AEs, and high adherence to therapy, aligning with expectations based on DRF clinical trials. Data were consistent in the DMF-to-DRF subgroup. INFOGRAPHIC.

Role of levosimendan in weaning children requiring veno-arterial extracorporeal membrane oxygenation after cardiac surgery.

OBJECTIVES: Levosimendan use is associated with more successful decannulation from veno-arterial extracorporeal membrane oxygenation (VA ECMO) in adults. We sought to determine the role of levosimendan in children who required VA ECMO after cardiac surgery. METHODS: This observational study compares the outcomes of children who required VA ECMO after cardiac surgery and received levosimendan for weaning with those who did not receive the drug. A doubly robust estimation methodology (inverse probability of treatment weighting with regression adjustment) was used to balance study covariates (age, weight, sex, lactate pre-ECMO, vasoactive-inotropic score pre-ECMO, ECMO indication, ECMO modality, Risk Adjustment for Congenital Heart Surgery-1 category), and the final model was further adjusted for duration of ECMO. RESULTS: Between January 2012 and December 2018, 118 eligible children received 145 ECMO runs [failed weaning from cardiopulmonary bypass, 67/145 (46%); low cardiac output state, 30/145 (21%); extracorporeal cardiopulmonary resuscitation, 47/145 (32%); other reasons in 1]. Levosimendan was administered before decannulation in 54/145 (37%) runs. The median time to start levosimendan after ECMO cannulation was 39 h (interquartile range, 14-83 h). The unadjusted rates of weaning failure in the levosimendan vs control group were 7% (4/54) vs 19% (17/91). In the controlled analysis, levosimendan was associated with decreased risk of weaning failure [adjusted relative risk (95% confidence interval), 0.20 (0.07-0.57)] and decreased risk of in-hospital mortality [adjusted relative risk (95% confidence interval), 0.45 (0.26-0.76)]. CONCLUSIONS: Levosimendan administration in children requiring VA ECMO after cardiac surgery was associated with decreased risk of weaning failure and decreased in-hospital mortality.

Pomalidomide is effective for prevention and treatment of experimental skin fibrosis.

OBJECTIVES: Tissue fibrosis is a major hallmark and a leading cause of death in systemic sclerosis (SSc). Here, we investigated the antifibrotic effects of pomalidomide, an analogue of thalidomide with potent immunomodulatory effects, in preclinical models of skin fibrosis. METHODS: We evaluated the antifibrotic effects of pomalidomide in preventive as well as therapeutic treatment regimes using bleomycin-induced dermal fibrosis as a model of early, inflammatory stages of fibrosis and the tight-skin mouse model as a model of later stages of fibrosis with endogenous activation of fibroblasts. RESULTS: Treatment with pomalidomide in doses from 0.3 to 30 mg/kd/day prevented skin fibrosis in Tsk-1 mice and in bleomycin-induced dermal fibrosis in a dose-dependent manner and reduced the expression of transforming growth factor (TGF) ß-target genes such as PAI-1, CTGF and col 1a1. Pomalidomide was also effective in the setting of pre-established fibrosis and reduced dermal thickness, myofibroblast counts and hydroxyproline content below pretreatment levels. CONCLUSIONS: We demonstrate for the first time that pomalidomide exerts potent antifibrotic effects in different preclinical models of skin fibrosis. These findings lend preclinical support for the clinical studies of pomalidomide in SSc.

Gas6/Axl signaling activates the phosphatidylinositol 3-kinase/Akt1 survival pathway to protect oligodendrocytes from tumor necrosis factor alpha-induced apoptosis.

Growth arrest-specific protein 6 (gas6) activity is mediated through the receptor tyrosine kinase family members Axl, Rse, and Mer, all of which are expressed in human oligodendrocytes. In this study, we examined whether recombinant human (rh) gas6 protects oligodendrocytes from growth factor (insulin) withdrawal or tumor necrosis factor-alpha (TNFalpha) cytotoxicity. In addition, we examined whether the effect was caspase-dependent, which receptor mediated the protective effect, and whether survival required Akt1 activation. Oligodendrocyte viability was assessed by O4 staining and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling. Addition of rhgas6 to insulin-depleted cultures resulted in a significant increase in oligodendrocyte viability. Rhgas6 and caspase inhibitors also reduced active caspase-3 immunoreactivity relative to TNFalpha-only-treated cultures. In cultures treated with TNFalpha (100 ng/ml), the oligodendrocyte survival rate was 18% compared with cultures treated with TNFalpha and rhgas6 (64%) or the caspase inhibitors IETD-fmk [z-Ile-Glu(OMe)-Thr-Asp(OMe)-fluoromethyl ketone] (65%) and zVAD-fmk (N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone) (63%). Increased phosphoAkt (Ser473) immunoreactivity was detected 15 min after administration of gas6 and TNFalpha to oligodendrocyte cultures but not in TNFalpha-treated cultures. The gas6 protective effect was abrogated by the Axl decoy receptor Axl-Fc, by the phosphatidylinositol 3 (PI3) kinase inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one], and in Akt1(-/-) oligodendrocytes. Oligodendrocyte cultures established from wild-type and Rse(-/-) mice, but not from Axl(-/-) mice, were also protected from TNFalpha-induced cell death when maintained in rhgas6. We conclude that gas6 signaling through the Axl receptor and the PI3 kinase/Akt1 survival pathway protects oligodendrocytes from growth factor withdrawal and TNFalpha-mediated cell death.

Inhibition of human neuroblastoma cell growth by CAY10404, a highly selective Cox-2 inhibitor.

Neuroblastomas constitute about 10% of childhood cancers and are responsible for 15% of pediatric cancer mortality. We evaluated the efficacy and the mechanism of cell death induced by CAY10404, a selective cyclooxygenase-2 (Cox-2) inhibitor in four human neuroblastoma cell lines (SH-EP, SH-SY5Y, SK-N-MC and MSN). Treatment with CAY10404 in the range of 15-115 microM revealed a dose-dependent decrease in cell number and an average IC50 (inhibitory concentration 50%) of 60 microM. About 20-30% of the cells were terminal deoxynucleotidyltransferase-mediated UTP nick-end-labeling (TUNEL) positive 48 h after treatment. Western blot analysis of CAY10404-treated cells showed poly(ADP-ribose) polymerase (PARP) cleavage and cleaved caspase-3 signifying caspase activity and apoptotic cell death. Inhibitor-of-apoptosis proteins including X-linked inhibitor-of-apoptosis protein (XIAP) and survivin did not change significantly after CAY10404 treatment. Fluorescence activated cell sorter (FACS) analysis performed in two different cell lines 48 h following CAY10404 treatment showed a reduction in the number of cells in the G1 phase of the cell cycle and an increase in the number of cells in the G2 phase. When radioresistant SH-EP cells were treated with CAY10404, a 49% decrease in cell viability was observed relative to DMSO-treated cells; pretreatment with CAY10404 followed by ortho-voltage irradiation further enhanced cell death (58%) suggesting radiosensitization by CAY10404.

UCN-01 alters phosphorylation of Akt and GSK3beta and induces apoptosis in six independent human neuroblastoma cell lines.

In this study we evaluated UCN-01, a small molecule that inhibits protein kinases by interacting with the ATP-binding site, as a potential anti-cancer agent for neuroblastoma. UCN-01 was effective at inducing apoptosis in six neuroblastoma cell lines with diverse cellular and genetic phenotypes. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) assays, detection of active caspase-3 and cleaved poly ADP-ribose polymerase (PARP) confirmed that UCN-01 induced apoptosis. Cell cycle analysis determined that the UCN-01 treated cells accumulated in S phase by 16 h. Unlike vinblastine and docetaxel that increased survivin expression, UCN-01 treatment did not increase X-linked inhibitor of apoptosis protein (XIAP) and survivin levels. Analysis of specific phosphoepitopes on chk1/2, Akt, and GSK3beta following UCN-01 treatment determined that there was no significant change in phospho-chk1/2. However, there was decreased immunoreactivity at Ser473 and Thr308 of Akt and Ser9 of GSK3beta by 4 h indicating that the Akt survival pathway and downstream signalling was compromised. Thus, UCN-01 was effective at inducing apoptosis in neuroblastoma cell lines.

The growth arrest-specific gene product Gas6 promotes the survival of human oligodendrocytes via a phosphatidylinositol 3-kinase-dependent pathway.

Microarray analysis revealed that transcripts for the Axl and Mer receptor tyrosine kinases are expressed at high levels in O4+-immunopanned oligodendrocytes isolated from second trimester human fetal spinal cord. In humans the sole known ligand for the Axl/Rse/Mer kinases is growth arrest-specific gene 6 (Gas6), which in the CNS is secreted by neurons and endothelial cells. We hypothesized that Gas6 is a survival factor for oligodendrocytes and receptor activation signals downstream to the phosphatidylinositol 3 (PI3)-kinase/Akt pathway to increase cell survival in the absence of cell proliferation. To test this hypothesis, we grew enriched human oligodendrocytes for 6 d on a monolayer of NIH3T3 cells stably expressing Gas6. CNP+ oligodendrocytes on Gas6-secreting 3T3 cells had more primary processes and arborizations than those plated solely on 3T3 cells. Also, a twofold increase in CNP+ and MBP+ oligodendrocytes was observed when they were plated on the Gas6-secreting cells. The effect was abolished in the presence of Axl-Fc but remained unchanged in the presence of the irrelevant receptor fusion molecule TrkA-Fc. A significant decrease in CNP+/TUNEL+ oligodendrocytes was observed when recombinant human Gas6 (rhGas6) was administered to oligodendrocytes plated on poly-L-lysine, supporting a role for Gas6 signaling in oligodendrocyte survival during a period of active myelination in human fetal spinal cord development. PI3-kinase inhibitors blocked the anti-apoptotic effect of rhGas6, whereas a MEK/ERK inhibitor had no effect. Thus Gas6 sustains human fetal oligodendrocyte viability by receptor activation and downstream signaling via the PI3-kinase/Akt pathway.

Up-regulation of MAP2e-expressing oligodendrocytes in the white matter of patients with HIV-1 encephalitis.

HIV-1 encephalitis (HIVE) is characterized by infection of macrophages and microglial cells, diffuse gliosis, and damage to neuronal populations. The nature of the white matter damage in HIVE remains elusive, and little is known about the status of the oligodendrocyte in HIVE. We have recently described a novel isoform of microtubule-associated protein-2 (MAP2e), which is expressed transiently in developing oligodendrocytes during myelination, and in remyelinating oligodendrocytes in multiple sclerosis lesions. In this study, we tested the hypothesis that MAP2e expression would be increased in the white matter of HIVE. We analysed brain sections from patients with HIVE and controls (HIV+ and HIV-) by immunocytochemistry and found that MAP2e+ cells are significantly increased in HIVE (range, 5-167 cells per cm2) compared to controls (range, 1-25 cells per cm2). MAP2e+ cells were negative for GFAP, CD68, LN3, RCA-1, von Willebrand factor and HIV-1 p24, but positive for MBP or Luxol-Fast Blue, supporting their oligodendroglial lineage. A topographical association between MAP2e and HIV-1 p24 expression was noted, but not between MAP2e and beta-APP, a marker of damaged axons. Our results demonstrate that MAP2e can serve as a marker of white matter damage in HIVE and support the notion that oligodendrocyte damage/repair occurs during HIV-1 infection.

Multiple sclerosis: re-expression of a developmental pathway that restricts oligodendrocyte maturation.

During mammalian central nervous system (CNS) development, contact-mediated activation of Notch1 receptors on oligodendrocyte precursors by the ligand Jagged1 induces Hes5, which inhibits maturation of these cells. Here we tested whether the Notch pathway is re-expressed in the adult CNS in multiple sclerosis (MS), an inflammatory demyelinating disease in which remyelination is typically limited. We found that transforming growth factor-beta 1 (TGF-beta 1), a cytokine upregulated in MS, specifically re-induced Jagged1 in primary cultures of human astrocytes. Within and around active MS plaques lacking remyelination, Jagged1 was expressed at high levels by hypertrophic astrocytes, whereas Notch1 and Hes5 localized to cells with an immature oligodendrocyte phenotype, and TGF-beta 1 was associated with perivascular extracellular matrix in the same areas. In contrast, there was negligible Jagged1 expression in remyelinated lesions. Experiments in vitro showed that Jagged1 signaling inhibited process outgrowth from primary human oligodendrocytes. These data are the first to implicate the Notch pathway in the limited remyelination in MS. Thus, Notch may represent a potential target for therapeutic intervention in this disease.