Neuroactive Steroids. 2. 3α-Hydroxy-3β-methyl-21-(4-cyano-1H-pyrazol-1'-yl)-19-nor-5β-pregnan-20-one (SAGE-217): A Clinical Next Generation Neuroactive Steroid Positive Allosteric Modulator of the (γ-Aminobutyric Acid)A Receptor

Certain classes of neuroactive steroids (NASs) are positive allosteric modulators (PAM) of synaptic and extrasynaptic GABA_A receptors. Herein, we report new SAR insights in a series of 5β-nor-19-pregnan-20-one analogues bearing substituted pyrazoles and triazoles at C-21, culminating in the discovery of 3α-hydroxy-3β-methyl-21-(4-cyano-1H-pyrazol-1'-yl)-19-nor-5β-pregnan-20-one (SAGE-217, 3), a potent GABA_A receptor modulator at both synaptic and extrasynaptic receptor subtypes, with excellent oral DMPK properties. Compound 3 has completed a phase 1 single ascending dose (SAD) and multiple ascending dose (MAD) clinical trial and is currently being studied in parallel phase 2 clinical trials for the treatment of postpartum depression (PPD), major depressive disorder (MDD), and essential tremor (ET).

Brexanolone (SAGE-547 injection) in post-partum depression: a randomised controlled trial

BACKGROUND

Post-partum depression is a serious mood disorder in women that might be triggered by peripartum fluctuations in reproductive hormones. This phase 2 study investigated brexanolone (USAN; formerly SAGE-547 injection), an intravenous formulation of allopregnanolone, a positive allosteric modulator of γ-aminobutyric acid (GABA_A) receptors, for the treatment of post-partum depression.

METHODS

For this double-blind, randomised, placebo-controlled trial, we enrolled self-referred or physician-referred female inpatients (≤6 months post partum) with severe post-partum depression (Hamilton Rating Scale for Depression [HAM-D] total score ≥26) in four hospitals in the USA. Eligible women were randomly assigned (1:1), via a computer-generated randomisation program, to receive either a single, continuous intravenous dose of brexanolone or placebo for 60 h. Patients and investigators were masked to treatment assignments. The primary efficacy endpoint was the change from baseline in the 17-item HAM-D total score at 60 h, assessed in all randomised patients who started infusion of study drug or placebo and who had a completed baseline HAM-D assessment and at least one post-baseline HAM-D assessment. Patients were followed up until day 30. This trial is registered with ClinicalTrials.gov, number NCT02614547.

FINDINGS

This trial was done between Dec 15, 2015 (first enrolment), and May 19, 2016 (final visit of the last enrolled patient). 21 women were randomly assigned to the brexanolone (n=10) and placebo (n=11) groups. At 60 h, mean reduction in HAM-D total score from baseline was 21·0 points (SE 2·9) in the brexanolone group compared with 8·8 points (SE 2·8) in the placebo group (difference -12·2, 95% CI -20·77 to -3·67; p=0·0075; effect size 1·2). No deaths, serious adverse events, or discontinuations because of adverse events were reported in either group. Four of ten patients in the brexanolone group had adverse events compared with eight of 11 in the placebo group. The most frequently reported adverse events in the brexanolone group were dizziness (two patients in the brexanolone group vs three patients in the placebo group) and somnolence (two vs none). Moderate treatment-emergent adverse events were reported in two patients in the brexanolone group (sinus tachycardia, n=1; somnolence, n=1) and in two patients in the placebo group (infusion site pain, n=1; tension headache, n=1); one patient in the placebo group had a severe treatment-emergent adverse event (insomnia).

INTERPRETATION

In women with severe post-partum depression, infusion of brexanolone resulted in a significant and clinically meaningful reduction in HAM-D total score, compared with placebo. Our results support the rationale for targeting synaptic and extrasynaptic GABA_A receptors in the development of therapies for patients with post-partum depression. A pivotal clinical programme for the investigation of brexanolone in patients with post-partum depression is in progress.

FUNDING

Sage Therapeutics, Inc.

Stabilization of bacterially expressed erythropoietin by single site-specific introduction of short branched PEG chains at naturally occurring glycosylation sites

The covalent attachment of polyethylene glycol (PEG) to therapeutic proteins can improve their physicochemical properties. In this work we utilized the non-natural amino acid p-azidophenylalanine (pAzF) in combination with the chemoselective Staudinger-phosphite reaction to install branched PEG chains to recombinant unglycosylated erythropoietin (EPO) at each single naturally occurring glycosylation site. PEGylation with two short 750 or 2000 Da PEG units at positions 24, 38, or 83 significantly decreased unspecific aggregation and proteolytic degradation while biological activity in vitro was preserved or even increased in comparison to full-glycosylated EPO. This site-specific bioconjugation approach permits to analyse the impact of PEGylation at single positions. These results represent an important step towards the engineering of site-specifically modified EPO variants from bacterial expression with increased therapeutic efficacy.

Open-label, proof-of-concept study of brexanolone in the treatment of severe postpartum depression

OBJECTIVE

Preclinical evidence indicates that rapid changes in levels of allopregnanolone, the predominant metabolite of progesterone, confer dramatic behavioral changes and may trigger postpartum depression (PPD) in some women. Considering the pathophysiology of PPD (i.e., triggered by reproductive steroids), the need for fast-acting, efficacious treatments and the negative consequences of untreated PPD, there is an increasing focus on developing PPD therapies. Brexanolone (USAN; formerly SAGE-547 Injection), a proprietary injectable allopregnanolone formulation, was evaluated as a treatment for severe PPD in a proof-of-concept, open-label study.

METHODS

Four women with severe PPD, defined as a baseline 17-item Hamilton Rating Scale for Depression (HAMD) score of ≥20, received brexanolone, titrated to a dose reflecting third-trimester allopregnanolone levels. After a 36-hour maintenance infusion, tapering occurred over 12 hours. Primary outcomes were measures of safety. Secondary outcomes were assessments of efficacy, including HAMD.

RESULTS

All enrolled patients completed the study. Fourteen adverse events were reported, of which none was severe. Starting at the first measure after infusion initiation and continuing through Hour 84, mean HAMD total scores were reduced to levels consistent with remission of symptoms. All other efficacy assessments showed similar improvements.

CONCLUSIONS

Brexanolone was well tolerated and demonstrated activity in severe PPD. Larger, double-blind trials are needed for further evaluation.

[Glaucoma-a common disease]

Glaucoma is the second leading cause of blindness worldwide. The purpose of this paper is to give a review on the epidemiology of the disease, on the importance and the consequences of glaucoma for people regarding their daily life, their ability to work, and quality of life.

Effects of the small molecule SIRT1 activator, SRT2104 on arterial stiffness in otherwise healthy cigarette smokers and subjects with type 2 diabetes mellitus

Objective

Arterial stiffness increases with age, and is associated with adverse cardiovascular outcome including increased mortality. The effect of the oral small molecule SIRT1 activator, SRT2104, on arterial stiffness was examined in otherwise healthy cigarette smokers and participants with type 2 diabetes mellitus.

Methods

24 otherwise healthy cigarette smokers and 15 people with stable type 2 diabetes were randomised in a double-blind placebo-controlled crossover trial and received 28 days of oral SRT2104 (2.0 g/day) or matched placebo. Blood pressure was measured using non-invasive oscillatory sphygmomanometry. Pulse wave analysis and velocity were measured using applanation tonometry at baseline and the end of each treatment period. Owing to the small sample size and similar trends for both groups, data for the two groups were pooled (post hoc analysis).

Results

Compared to placebo, treatment with SRT2104 was associated with a significant reduction in augmentation pressure (p=0.0273) and a trend towards improvement in the augmentation index and corrected augmentation index (p>0.05 for both). However, no changes were observed in pulse wave velocity and time to wave reflection (p>0.05). Systolic and diastolic blood pressures remained unchanged throughout the study. Treatment by cohort interaction was not significant for any of the pulse wave parameters, suggesting that the response to SRT2104 in otherwise healthy smokers and people with diabetes was consistent.

Conclusions

SRT2104 may improve measures of arterial stiffness in otherwise healthy cigarette smokers and in participants with type 2 diabetes. Definitive conclusions are not possible given the small sample size and exploratory nature of this analysis.

Trial registration number

NCT01031108.

A phase II, randomized, placebo-controlled, double-blind, multi-dose study of SRT2104, a SIRT1 activator, in subjects with type 2 diabetes

AIM

SRT2104 is a selective activator of SIRT1. In animal models, SRT2104 improves glucose homeostasis and increases insulin sensitivity. We evaluated the tolerability and pharmacokinetics of SRT2104, and its effects on glycaemic control, in adults with type 2 diabetes mellitus.

METHOD

Type 2 diabetics with glycosylated haemoglobin (HbA1c) ≥ 7.5% and ≤10.5%, fasting glucose ≥160 and ≤240 mg dl(-1) , and on stable doses of metformin were evenly randomized to placebo or SRT2104 0.25 g, 0.5 g, 1.0 g or 2.0 g, administered orally once daily for 28 days. Changes in fasting and post-prandial glucose and insulin were analyzed.

RESULTS

Safety evaluation found no major differences between groups in the frequency of adverse events. SRT2104 concentrations did not increase in a dose-proportional fashion. Significant variability in exposure was observed. Treatment with SRT2104 did not lead to any consistent, dose-related changes in glucose or insulin. Day 28 change from baseline (mean (SD)): fasting glucose (mmol l(-1) ) = -1.17 (2.42), -1.11 (3.45), -0.52 (2.60), -0.97 (2.83) and -0.15 (2.38) for placebo, 0.25 g, 0.5 g, 1.0 g and 2.0 g, respectively. Day 28 change from baseline (mean (SD)): fasting insulin (mmol l(-1) ) = 1.0 (51.66), 8.9 (95.04), -6.9 (41.45), 4.1 (57.16) and 15.2 (138.79) for placebo, 0.25 g, 0.5 g, 1.0 g and 2.0 g, respectively) Treatment with SRT2104 was associated with improvement in lipid profiles.

CONCLUSION

Treatment with SRT2104 for 28 days did not result in improved glucose or insulin control which is likely due to the observed pharmacokinetics which were not dose proportional and had large between subject variability.

Demonstration of Confined Electron Gas and Steep-Slope Behavior in Delta-Doped GaAs-AlGaAs Core-Shell Nanowire Transistors

Strong surface and impurity scattering in III-V semiconductor-based nanowires (NW) degrade the performance of electronic devices, requiring refined concepts for controlling charge carrier conductivity. Here, we demonstrate remote Si delta (δ)-doping of radial GaAs-AlGaAs core-shell NWs that unambiguously exhibit a strongly confined electron gas with enhanced low-temperature field-effect mobilities up to 5 × 10(3) cm(2) V(-1) s(-1). The spatial separation between the high-mobility free electron gas at the NW core-shell interface and the Si dopants in the shell is directly verified by atom probe tomographic (APT) analysis, band-profile calculations, and transport characterization in advanced field-effect transistor (FET) geometries, demonstrating powerful control over the free electron gas density and conductivity. Multigated NW-FETs allow us to spatially resolve channel width- and crystal phase-dependent variations in electron gas density and mobility along single NW-FETs. Notably, dc output and transfer characteristics of these n-type depletion mode NW-FETs reveal excellent drain current saturation and record low subthreshold slopes of 70 mV/dec at on/off ratios >10(4)-10(5) at room temperature.

Neuroactive Steroids. 1. Positive Allosteric Modulators of the (γ-Aminobutyric Acid)A Receptor: Structure-Activity Relationships of Heterocyclic Substitution at C-21

Neuroactive steroids (NASs) have been shown to impact central nervous system (CNS) function through positive allosteric modulation of the GABA(A) receptor (GABA(A)-R). Herein we report the effects on the activity and pharmacokinetic properties of a series of nor-19 pregnanolone analogues bearing a heterocyclic substituent at C-21. These efforts resulted in the identification of SGE-516, a balanced synaptic/extrasynaptic GABA(A) receptor modulator, and SGE-872, a selective extrasynaptic GABA(A) receptor modulator. Both molecules possess excellent druglike properties, making them advanced leads for oral delivery of GABA(A) receptor modulators.

Practitioner experience with sonic osteotomy compared to bur and ultrasonic saw: a pilot in vitro study

The aim of the present study was to compare subjective experiences using bur, ultrasonic, and sonic osteotomy systems. Ten novice (N) and 10 expert (E) practitioners performed osteotomies on bovine ribs with each system. They scored ease of handling and sense of accuracy on visual analogue scales. The duration of the osteotomy procedure and the amount of noise were recorded objectively. Learning experience was evaluated in a second run. The Mann-Whitney U-test, Wilcoxon signed rank tests, and Spearman's rank correlation coefficient were used for the statistical analyses. The sonic system was significantly slower, with the worst noise impact (92.9dB; standard deviation (SD) 7.1). However, both user groups improved significantly in the second run (N 7.9, E 7.6). There were no significant differences in handling. The sense of accuracy was evaluated to be significantly best for the sonic system (N 8.4, E 8.4), compared to the ultrasonic system (N 7.1, E 7.1; both P=0.043) and bur system (N 5.5, P=0.002; E 6.0, P=0.006). The practitioners had a promising experience with the application of the ultrasonic system and particularly with the sonic system.

[Anticoagulation in high thromboembolic risk after catheter ablation for atrial fibrillation: results from the German Ablation Registry]

BACKGROUND

Catheter ablation (CA) for atrial fibrillation (AF) is an effective therapeutic option for the treatment of symptomatic drug-refractory AF. According to current guidelines, the prevention of stroke and embolism is the most important therapeutic goal in AF and the recommendations for anticoagulation (OAC) after successful CA are based upon the CHA2DS2-VASc-Score 3. The aim of this study was to evaluate the use of OAC in patients with a high risk for thromboembolic events 1 year after CA and to identify predictor variables for discontinuation of OAC.

METHODS

Between January 2007 and January 2010 13092 patients were enrolled in the study. A total of 52 German electrophysiological centers agreed to participate in this prospective multicenter registry. 41 centers included patients undergoing CA for AF. Analysis included patients who were discharged with OAC after CA and had a CHA2DS2-VASc-Score ≥ 2. A centralized 1 year follow-up (FU) was conducted via telephone.

RESULTS

1300 patients fulfilled the inclusion criteria. One year after CA 51.8 % of these patients were on OAC. Factors significantly associated with discontinuation of OAC included no AF recurrence in FU (adjusted odds ratio (OR): 2.14, [95 % confidence interval (CI): 1.73-2.66], P < 0.001) and paroxysmal AF (OR: 1.53 [95 % CI: 1.29-1.81], P < 0.001). Factors associated with continuation of OAK were patient age (OR per 10 years: 0.79 [95 % CI: 0.68-0.91], P = 0.002), valvular heart disease (OR: 0.67 [95 % CI: 0.48-0.92], P = 0.013), an implanted pacemaker, defibrillator or a cardiac resynchronization therapy system (OR: 0.55 [95 % CI: 0.41-0.74], P < 0.001) and neurological events in hospital or during FU (OR: 0.40 [95 % CI: 0.18-0.88], P < 0.022).

CONCLUSION

Almost half of the patients with an indication for OAC are not adequately anticoagulated one year after CA for AF. Paroxysmal AF or freedom from AF is significantly associated with discontinuation of OAC.

Ethanol self-administration and nicotine treatment increase brain levels of CYP2D in African green monkeys

BACKGROUND AND PURPOSE

CYP2D6 metabolizes many centrally acting drugs, neurotoxins and endogenous neurochemicals, and differences in brain levels of CYP2D have been associated with brain function and drug response. Alcohol consumers and smokers have higher levels of CYP2D6 in brain, but not liver, suggesting ethanol and/or nicotine may induce human brain CYP2D6. We investigated the independent and combined effects of chronic ethanol self-administration and nicotine treatment on CYP2D expression in African green monkeys.

EXPERIMENTAL APPROACH

Forty monkeys were randomized into control, ethanol-only, nicotine-only and ethanol + nicotine groups. Two groups voluntarily self-administered 10% ethanol in sucrose solution for 4 h·day(-1) , whereas two groups consumed sucrose solution on the same schedule. Two groups received daily s.c. injections of 0.5 mg·kg(-1) nicotine in saline bid, whereas two groups were injected with saline on the same schedule.

KEY RESULTS

Both nicotine and ethanol dose-dependently increased CYP2D in brain; brain mRNA was unaffected, and neither drug altered hepatic CYP2D protein or mRNA. The combination of ethanol and nicotine increased brain CYP2D protein levels to a greater extent than either drug alone (1.2-2.2-fold, P < 0.05 among the eight brain regions assessed). Immunohistochemistry revealed the induction of brain CYP2D protein within specific cell types and regions in the treatment groups.

CONCLUSIONS AND IMPLICATIONS

Ethanol and nicotine increase brain CYP2D protein levels in monkeys, in a region and treatment-specific manner, suggesting that CNS drug responses, neurodegeneration and personality may be affected among people who consume alcohol and/or nicotine.

Sacro-iliac joint arthroscopy for arthrodesis after traumatic dislocation. Cadaver and clinical feasibility study

BACKGROUND

Sacro-iliac arthrodesis usually requires an extended posterior approach, which is associated with a number of dreaded complications. Here, we assessed the feasibility of arthroscopic exploration of the dislocated sacro-iliac joint.

MATERIALS AND METHODS

In the first step of our study, we used ligament section to induce loss of sacro-iliac joint coaptation in a cadaver. We then studied 5 patients with Tile C pelvic ring injuries. Arthroscopy was used to clear the joint of fibrous tissue and to roughen the bone to subchondral level in order to induce sacro-iliac arthrodesis. In addition, posterior fixation was performed using a hinge system or an ilio-sacral screw.

RESULTS

The cadaver study confirmed the feasibility of sacro-iliac arthroscopy after disruption of the strong posterior inter-osseous ligament. In the clinical part of the study in 5 patients with Tile C pelvic ring injuries, arthroscopy allowed direct visualisation extending to the anterior part of the joint space. A power burr and synovial knife were introduced to remove the interposed fibrous tissue and to roughen the bone to subchondral level in order to induce joint fusion. In addition, percutaneous or open posterior fixation was performed in all 5 patients. No infectious complications were recorded.

DISCUSSION

An arthroscope cannot be introduced into the normal sacro-iliac joint. In contrast, after traumatic sacro-iliac dislocation, arthroscopy can be used to evaluate the intra-articular injuries and to roughen the bone to subchondral level.

Atmospheric transport modelling of time resolved 133Xe emissions from the isotope production facility ANSTO, Australia

The verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT) relies amongst other things on the continuous and worldwide monitoring of radioxenon. The characterization of the existing and legitimate background, which is produced mainly by nuclear power plants and isotope production facilities, is of high interest to improve the capabilities of the monitoring network. However, the emissions from legitimate sources can usually only be estimated. For this paper historic source terms of (133)Xe emissions from the isotope production facility at ANSTO, Sydney, Australia, have been made available in a daily resolution. Based on these high resolution data, different source term sets with weekly, monthly and yearly time resolution have been compiled. These different sets are then applied together with atmospheric transport modelling (ATM) to predict the concentration time series at two radioxenon monitoring stations. The results are compared with each other in order to examine the improvement of the prediction capability depending on the used time resolution of the most dominant source term in the region.