Clinical outcomes in patients with relapsing-remitting multiple sclerosis who switch from natalizumab to delayed-release dimethyl fumarate: A multicenter retrospective observational study (STRATEGY).

BACKGROUND: Delayed-release dimethyl fumarate (DMF) may be a therapeutic option for patients with relapsing-remitting multiple sclerosis (RRMS) who are treated with natalizumab and require a change in therapy. However, there is limited information regarding predictors of favorable treatment outcomes in patients switching from natalizumab to DMF. Clinical practices and sequencing protocols vary. Herein, we present the clinical results, including annualized relapse rate (ARR) and risk of relapse, of a phase 4 retrospective observational study of patients with RRMS who switched from natalizumab to DMF in a community practice setting (STRATEGY). METHODS: STRATEGY was performed through a single time point medical record abstraction; no study visits or procedures were required. Key inclusion criteria included age ≥ 18 years, RRMS diagnosis (McDonald criteria, 2010 revised), ≥ 12 months of continuous treatment with natalizumab monotherapy before DMF initiation, and initiation of DMF ≥ 12 months before enrollment. Patients were eligible to enroll regardless of current DMF use. RESULTS: A total of 530 patients at 45 US sites enrolled, and 506 met the inclusion criteria and were included in the modified evaluable population for analysis. Mean (SD) age at DMF initiation was 47.0 (10.9) years, with a mean (SD) of 12.7 (7.2) years since MS diagnosis. The mean (SD) duration of natalizumab treatment was 3.4 (1.9) years, and the mean (SD) washout from natalizumab discontinuation to DMF initiation (n = 502) was 101.6 (164.0) days. Overall risk of relapse 12 months after DMF initiation was 19.6%. Overall unadjusted ARR was higher during the 12 months following initiation of DMF treatment compared with the 12 months following initiation of natalizumab treatment (rate ratio, 2.32 [95% CI, 1.69-3.18]; p < 0.0001), but was lower compared with that observed in the year before initiation of natalizumab (rate ratio, 0.51 [95% CI, 0.40-0.64]; p < 0.0001). At 1 year following initiation of DMF treatment, the relapse rate was lower for patients who did not experience a relapse during 1 year following initiation of natalizumab treatment than for those who did (rate ratio for relapse rate, 0.47 [95% CI, 0.16-1.38]; p = 0.1664). The relapse rate for patients who did not relapse during natalizumab treatment was significantly lower with a washout period of ≤ 90 days as compared with a washout period of > 90 days (rate ratio for relapse rate, 0.49 [95% CI, 0.26-0.90]; p = 0.0216). A total of 42 (8%) patients reported ≥ 1 adverse event leading to DMF discontinuation during the study; the most commonly reported events were gastrointestinal disorders (n = 21; 4%). CONCLUSIONS: Results from this multicenter retrospective observational study suggest that DMF may be an effective treatment option for patients who discontinue natalizumab in routine clinical practice. ARR was lower in patients who initiated DMF within 90 days of natalizumab discontinuation compared with patients who initiated DMF after 90 days of natalizumab discontinuation. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT02159573.

Treatment of patients with pulmonary arterial hypertension at the time of death or deterioration to functional class IV: insights from the REVEAL Registry.

BACKGROUND: Current guidelines recommend intravenous prostacyclin as first-line therapy for patients with pulmonary arterial hypertension (PAH) in New York Heart Association/World Health Organization functional class (FC) IV, or combination therapy for patients in any FC who do not respond to monotherapy. We investigated the aggressiveness of therapy in patients enrolled in the REVEAL (Registry to Evaluate Early and Long-Term PAH Disease Management) Registry who deteriorated to FC IV or died. METHODS: Among 3,515 patients (age ≥ 18 years) in REVEAL with a mean pulmonary artery pressure ≥ 25 mm Hg and pulmonary capillary wedge pressure ≤ 15 mm Hg, we examined three sub-sets: the 487 patients who had a PAH-related death, the larger set of 908 patients who died from any cause (PAH-related, not PAH-related, or unknown), and the 294 patients who were FC I, II, or III at enrollment and later assessed as FC IV. RESULTS: Among patients who died, 56% (n = 272 of 487) and 43% (n = 391 of 908) were receiving intravenous prostacyclin before death in the PAH-related death and all-cause death cohorts, respectively. In the PAH-related death cohort, 60% and 16% of patients were most recently assessed as FC III and IV, respectively; among those assessed as FC IV within 6 months of death, 57.7% (n = 15 of 26) had received intravenous prostacyclin. Because many patients died without an observed assessment of worsening to FC IV, we also evaluated medication use among the cohort of patients who worsened to FC IV during the study. One day before worsening to FC IV, 150 of 294 patients were not receiving intravenous prostacyclin and 70 were receiving only PAH-specific monotherapy; of these, 61% and 67%, respectively, received no additional therapy 90 days later. CONCLUSIONS: Intravenous prostacyclin and combination therapy are not consistently used in the most seriously ill patients enrolled in REVEAL after being assessed as FC IV or at the time of death.

Evaluation of the predictive value of a clinical worsening definition using 2-year outcomes in patients with pulmonary arterial hypertension: a REVEAL Registry analysis.

BACKGROUND: Time to clinical worsening has been proposed as a primary end point in clinical trials of pulmonary arterial hypertension (PAH); however, neither standardized nor validated definitions of clinical worsening across PAH trials exist. This study aims to evaluate a proposed definition of clinical worsening within a large prospective, observational registry of patients with PAH with respect to its value as a predictor of proximate (within 1 year) risk for subsequent major events (ie, death, transplantation, or atrial septostomy). METHODS: We assessed overall 2-year survival and survival free from major events to determine the relationship between clinical worsening and major events among adults with hemodynamically defined PAH (N = 3,001). Freedom from clinical worsening was defined as freedom from worsening functional class (FC), a ≥ 15% reduction in 6-min walk distance (6MWD), all-cause hospitalization, or the introduction of parenteral prostacyclin analog therapy. RESULTS: In the 2 years of follow-up, 583 patients died. Four hundred twenty-six died after a documented clinical worsening event, including FC worsening (n = 128), a ≥ 15% reduction in 6MWD (n = 118), all-cause hospitalization (n = 370), or introduction of a prostacyclin analog (n = 91). Patients who experienced clinical worsening had significantly poorer subsequent 1-year survival postworsening than patients who did not worsen (P < .001). CONCLUSIONS: Clinical worsening was highly predictive of subsequent proximate mortality in this analysis from an observational study. These results validate the use of clinical worsening as a meaningful prognostic tool in clinical practice and as a primary end point in clinical trial design. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00370214; URL: www.clinicaltrials.gov.

Comorbid conditions and outcomes in patients with pulmonary arterial hypertension: a REVEAL registry analysis.

BACKGROUND: Comorbidities can affect disease progression and/or response to treatment in various conditions. Comorbid conditions are prevalent in patients with pulmonary arterial hypertension (PAH); however, their effect on patient outcomes remains unknown. METHODS: We evaluated the effect on functional class (FC), 6-min walk test distance (6MWD), and survival of the seven most common, comorbid conditions at enrollment in patients with PAH from the Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL Registry): hypertension, clinical depression, type 2 diabetes mellitus (diabetes), obesity, COPD, sleep apnea, and thyroid disease. RESULTS: Patients with COPD or diabetes had the shortest 6MWD at enrollment (304.5 and 304.6 m, respectively) vs other comorbidities. Adjusted linear regression for 6MWD at enrollment revealed significant reductions among patients who were hypertensive, obese, diabetic, or had COPD (P<.001). A larger proportion of patients who were obese or had COPD were FC III/IV vs FC I/II at enrollment (P<.001). There was a greater risk for death among patients with diabetes (hazard ratio [HR], 1.73; 95% CI, 1.40-2.13; P<.001) or COPD (HR, 1.59; 95% CI, 1.34-1.90; P<.001), but there was a reduced risk for death in patients who were obese (HR, 0.73; 95% CI, 0.61-0.86; P<.001). CONCLUSIONS: Compared with other analyzed comorbidities in patients with PAH, hypertension, obesity, diabetes, and COPD were associated with significantly worse 6MWD; obesity and COPD were associated with worse FC; and diabetes and COPD were associated with increased risk for death. Further investigation of the effects of treating these comorbidities in patients with PAH is warranted. TRIAL REGISTRY: ClinicalTrials.gov; Identifier: NCT00370214; URL: www.clinicaltrials.gov.

Induced chromosome deletions cause hypersociability and other features of Williams-Beuren syndrome in mice.

The neurodevelopmental disorder Williams-Beuren syndrome is caused by spontaneous approximately 1.5 Mb deletions comprising 25 genes on human chromosome 7q11.23. To functionally dissect the deletion and identify dosage-sensitive genes, we created two half-deletions of the conserved syntenic region on mouse chromosome 5G2. Proximal deletion (PD) mice lack Gtf2i to Limk1, distal deletion (DD) mice lack Limk1 to Fkbp6, and the double heterozygotes (D/P) model the complete human deletion. Gene transcript levels in brain are generally consistent with gene dosage. Increased sociability and acoustic startle response are associated with PD, and cognitive defects with DD. Both PD and D/P males are growth-retarded, while skulls are shortened and brains are smaller in DD and D/P. Lateral ventricle (LV) volumes are reduced, and neuronal cell density in the somatosensory cortex is increased, in PD and D/P. Motor skills are most impaired in D/P. Together, these partial deletion mice replicate crucial aspects of the human disorder and serve to identify genes and gene networks contributing to the neural substrates of complex behaviours and behavioural disorders.

Adult neurogenesis, mental health, and mental illness: hope or hype?

Psychiatric and neurologic disorders take an enormous toll on society. Alleviating the devastating symptoms and consequences of neuropsychiatric disorders such as addiction, depression, epilepsy, and schizophrenia is a main force driving clinical and basic researchers alike. By elucidating these disease neuromechanisms, researchers hope to better define treatments and preventive therapies. Research suggests that regulation of adult hippocampal neurogenesis represents a promising approach to treating and perhaps preventing mental illness. Here we appraise the role of adult hippocampal neurogenesis in major psychiatric and neurologic disorders within the essential framework of recent progress made in understanding "normal" adult neurogenesis. Topics addressed include the following: the life cycle of an adult hippocampal stem cell and the implications for aging; links between learning and hippocampal neurogenesis; the reciprocal relationship between cocaine self-administration and adult hippocampal neurogenesis; the role of adult neurogenesis in an animal model of depression and response to antidepressant exposure; the impact of neonatal seizures on dentate gyrus neurogenesis; and the contribution of a schizophrenia-susceptibility gene to adult hippocampal neurogenesis. These topics are discussed in light of the regulation of adult neurogenesis, the relationship to normal neurogenesis in adulthood and aging, and, importantly, the manipulation of neurogenesis to promote mental health and treat mental illness.

Integration of light-controlled neuronal firing and fast circuit imaging.

For understanding normal and pathological circuit function, capitalizing on the full potential of recent advances in fast optical neural circuit control will depend crucially on fast, intact-circuit readout technology. First, millisecond-scale optical control will be best leveraged with simultaneous millisecond-scale optical imaging. Second, both fast circuit control and imaging should be adaptable to intact-circuit preparations from normal and diseased subjects. Here we illustrate integration of fast optical circuit control and fast circuit imaging, review recent work demonstrating utility of applying fast imaging to quantifying activity flow in disease models, and discuss integration of diverse optogenetic and chemical genetic tools that have been developed to precisely control the activity of genetically specified neural populations. Together these neuroengineering advances raise the exciting prospect of determining the role-specific cell types play in modulating neural activity flow in neuropsychiatric disease.

An optical neural interface: in vivo control of rodent motor cortex with integrated fiberoptic and optogenetic technology.

Neural interface technology has made enormous strides in recent years but stimulating electrodes remain incapable of reliably targeting specific cell types (e.g. excitatory or inhibitory neurons) within neural tissue. This obstacle has major scientific and clinical implications. For example, there is intense debate among physicians, neuroengineers and neuroscientists regarding the relevant cell types recruited during deep brain stimulation (DBS); moreover, many debilitating side effects of DBS likely result from lack of cell-type specificity. We describe here a novel optical neural interface technology that will allow neuroengineers to optically address specific cell types in vivo with millisecond temporal precision. Channelrhodopsin-2 (ChR2), an algal light-activated ion channel we developed for use in mammals, can give rise to safe, light-driven stimulation of CNS neurons on a timescale of milliseconds. Because ChR2 is genetically targetable, specific populations of neurons even sparsely embedded within intact circuitry can be stimulated with high temporal precision. Here we report the first in vivo behavioral demonstration of a functional optical neural interface (ONI) in intact animals, involving integrated fiberoptic and optogenetic technology. We developed a solid-state laser diode system that can be pulsed with millisecond precision, outputs 20 mW of power at 473 nm, and is coupled to a lightweight, flexible multimode optical fiber, approximately 200 microm in diameter. To capitalize on the unique advantages of this system, we specifically targeted ChR2 to excitatory cells in vivo with the CaMKIIalpha promoter. Under these conditions, the intensity of light exiting the fiber ( approximately 380 mW mm(-2)) was sufficient to drive excitatory neurons in vivo and control motor cortex function with behavioral output in intact rodents. No exogenous chemical cofactor was needed at any point, a crucial finding for in vivo work in large mammals. Achieving modulation of behavior with optical control of neuronal subtypes may give rise to fundamental network-level insights complementary to what electrode methodologies have taught us, and the emerging optogenetic toolkit may find application across a broad range of neuroscience, neuroengineering and clinical questions.

High-speed imaging reveals neurophysiological links to behavior in an animal model of depression.

The hippocampus is one of several brain areas thought to play a central role in affective behaviors, but the underlying local network dynamics are not understood. We used quantitative voltage-sensitive dye imaging to probe hippocampal dynamics with millisecond resolution in brain slices after bidirectional modulation of affective state in rat models of depression. We found that a simple measure of real-time activity-stimulus-evoked percolation of activity through the dentate gyrus relative to the hippocampal output subfield-accounted for induced changes in animal behavior independent of the underlying mechanism of action of the treatments. Our results define a circuit-level neurophysiological endophenotype for affective behavior and suggest an approach to understanding circuit-level substrates underlying psychiatric disease symptoms.

A role for circuit homeostasis in adult neurogenesis.

Insertion of new neurons into adult neural circuits could either promote or impair circuit function, depending on whether homeostatic mechanisms are in place to regulate the resulting changes in neural activity. In the hippocampus (a mammalian forebrain structure important in aspects of memory and mood) several lines of behavioral evidence suggest important adaptive roles for adult-generated neurons, indicating that there could be mechanisms to control the potentially adverse increase in excitation associated with new cells. Here, we delineate behavioral and computational models for the role of circuit homeostasis in enabling neuron insertion to modulate hippocampal function adaptively, and we describe molecular and cellular mechanisms for implementing this circuit-level adaptive regulation of hippocampal activity.