Indirect adjusted comparison of 6-month clinical outcomes between esketamine nasal spray and other real-world polypharmacy treatment strategies for treatment resistant depression: results from the ICEBERG study.

Background: The efficacy of esketamine nasal spray (NS) as a rapid-acting agent for treatment resistant depression (TRD) was demonstrated in comparisons with placebo, when both were given in addition to a newly initiated selective serotonin reuptake inhibitor (SSRI)/serotonin norepinephrine reuptake inhibitor (SNRI). How esketamine NS compares with commonly used real-world (RW) polypharmacy treatment strategies is not known. Method: ICEBERG was an adjusted indirect treatment comparison that analysed data from SUSTAIN-2 (NCT02497287; clinicaltrials.gov), a long-term, open-label study of esketamine NS plus SSRI/SNRI, and the European Observational TRD Cohort (EOTC; NCT03373253; clinicaltrials.gov), an observational study of routine clinical practice. Data were compared between patients receiving esketamine NS (SUSTAIN-2) and those from the EOTC treated with polypharmacy treatment strategies, either combination or augmentation. Analyses were adjusted for potential confounders, using rescaled average treatment effect among treated estimates. Threshold analyses were conducted to assess potential impact of unmeasured confounders on the robustness of analyses where esketamine NS was found to be significantly superior. Sensitivity analyses were used to understand the impact of analysis method selection and data handling. Results: Esketamine NS treatment resulted in a higher probability of 6-month response (49.7% [95% confidence interval (CI) 45.6-53.9]) and remission (33.6% [95% CI 29.7-37.6]) versus RW polypharmacy (26.8% [95% CI 21.0-32.5] and 19.4%, [95% CI 14.2-24.6], respectively). Relative risk calculations showed esketamine NS was 1.859 (95% CI 1.474-2.345; p < 0.0001) times as likely to result in response and 1.735 (1.297-2.322; p = 0.0002) times as likely to result in remission versus RW polypharmacy at 6 months. Threshold and extensive sensitivity analyses supported that analyses of esketamine NS superiority were robust. Conclusion: ICEBERG supports esketamine NS being superior to current RW individualized polypharmacy strategies, including augmentation, with benefits extending beyond acute use, to improved chance of 6-month response and remission. While unobserved confounding factors may certainly impact results of an indirect comparison, threshold analysis supported a low likelihood of this affecting the conclusions.To view an animated summary of this publication, please click on the Supplementary video.

ICEBERG study: an indirect adjusted comparison estimating the long-term benefit of esketamine nasal spray when compared with routine treatment of treatment resistant depression in general psychiatry.

Background: Treatment resistant depression (TRD) affects 10-30% of patients with major depressive disorder. In 4-week trials, esketamine nasal spray (NS) was efficacious vs. placebo when both were initiated in addition to a new selective serotonin or serotonin norepinephrine reuptake inhibitor. However, comparison with an extended range of real-world treatments (RWT) is lacking. Methods: ICEBERG was an adjusted indirect treatment comparison using propensity score-based inverse probability weighting, performed on 6-month response and remission data from patients receiving esketamine NS plus oral antidepressant from the SUSTAIN-2 (NCT02497287; clinicaltrials.gov) study, compared with patients receiving other RWT from the European Observational TRD Cohort (EOTC; NCT03373253; clinicaltrials.gov) study. SUSTAIN-2 was a long-term open-label study of esketamine NS, while the EOTC was conducted at a time when esketamine NS was not available as RWT. Threshold and sensitivity analyses were conducted to assess how robust the primary analyses were. Results: Patients receiving esketamine NS had a higher probability of 6-month response (49.7% [95% confidence interval (CI) 45.6-53.9]) and remission (33.6% [95% CI 29.7-37.6]) vs. patients receiving RWT (26.4% [95% CI 21.5-31.4] and 18.2% [95% CI 13.9-22.5], respectively), according to rescaled average treatment effect among treated estimates. Resulting adjusted odds ratios (OR) and relative risk (RR) favoured esketamine NS over RWT for 6-month response (OR 2.756 [95% CI 2.034-3.733], p < 0.0001; RR 1.882 [95% CI 1.534-2.310], p < 0.0001) and remission (OR 2.276 [95% CI 1.621-3.196], p < 0.0001; RR 1.847 [95% CI 1.418-2.406], p < 0.0001). Threshold analyses suggested that differences between the two studies were robust, and results were consistent across extensive sensitivity analyses. Conclusion: ICEBERG supports that, at 6 months, esketamine NS has a substantial and significant benefit over RWT for patients with TRD. While results may be affected by unobserved confounding factors, threshold analyses suggested these were unlikely to impact the study conclusions.To view an animated summary of this publication, please click on the Supplementary video.

Use of Clinical Global Impressions-Severity (CGI-S) to Assess Response to Antidepressant Treatment in Patients with Treatment-Resistant Depression.

Background: This post-hoc analysis evaluated the agreement between Clinical Global Impressions-Severity (CGI-S) score- and Montgomery-Åsberg Depression Rating Scale (MADRS) total score-based assessment of response in patients with treatment-resistant depression (TRD) treated with esketamine nasal spray plus a newly initiated oral antidepressant (ESK-NS + AD). Methods: Data were analyzed from a phase 3, randomized, double-blind study (TRANSFORM-2) of flexibly dosed esketamine or placebo nasal spray plus a newly initiated oral-AD in adults with moderate-to-severe TRD. Patients with ≥50% reduction in MADRS from baseline at the end of the 4-week acute treatment phase were defined as responders. For the CGI-S-based assessment of response, patients with ≥2 points decrease from baseline or a CGI-S score of ≤3 (mildly depressed to normal) were considered responders. Cohen's kappa coefficient was calculated to assess level of agreement between MADRS and CGI-S-based assessments. Results: At the end of 4-week treatment, the proportion of responders among all study patients (n=201) was similar when assessed using the MADRS (61%) and CGI-S (62%) methods, with substantial agreement (Cohen's kappa=0.76; sensitivity=92%; specificity=84%) between both methods. When restricting analysis to ESK-NS + AD-treated patients (n=101) who had a higher response rate (on MADRS: 69%; on CGI-S: 68%), the agreement remained substantial (Cohen's kappa=0.75; sensitivity=91%; specificity=84%). Conclusion: The CGI-S may be a practical and reliable alternative to the MADRS to assess response to ESK-NS + AD in patients with TRD and can be used in real-world practice to support informed treatment decisions.

Clinical Features and Outcomes of 124 Italian Patients With Treatment Resistant Depression: A Real-World, Prospective Study.

Introduction: Treatment-resistant depression (TRD) is a debilitating condition affecting 20-30% of patients with major depressive disorders (MDD). Currently, there is no established standard of care for TRD, and wide variation in the clinical approach for disease management has been documented. Real-world data could help describe TRD clinical features, disease burden, and treatment outcome and identify a potential unmet medical need. Methods: We analyzed the Italian data from a European, prospective, multicentric, observational cohort study of patients fulfilling TRD criteria by the European Medicine Agency, with moderate to severe major depressive episode, and starting a new antidepressant treatment according to routinary clinical practice. They were followed up for minimum 6 months. Treatments received throughout the study period, disease severity, health-related quality of life and functioning were prospectively recorded and analyzed. Results: The Italian subcohort included 124 TRD patients (30.2% of patients of the European cohort; mean age 53.2 [sd = 9.8], women: 82, 66.1%). At enrollement, the mean (SD) duration of MDD was 16 years (sd = 11.1) and the mean duration of the ongoing major depressive episode (MDE) was 97.5 weeks (sd = 143.5); low scores of quality of life and functioning were reported. The most frequently antidepressant classes started at baseline (data available for 98 subjects) were selective serotonin reuptake inhibitors (SSRI, 42 patients [42.9%]) and serotonin-norepinephrine reuptake inhibitors (SNRI, 32 patients [32.7%]). In terms of treatment strategies, 50 patients (51%) started augmentation therapies, 18 (18.4%) combination therapies and 24 (24.5%) monoterapies (6 patients [6%] started a non-antidepressant drug only). Fourteen patients (11.3%) were treated with a psychosocial approach, including psychotherapy. After 6 months of treatment, clinical assessments were collected for 89 patients: 64 (71.9%) showed no response, 9 (10.1%) response without remission and 16 (18.0%) were in remission; non-responder patients showed lower quality of life and higher disability scores than responder patients. Conclusions: In our sample of TRD patients, we documented substantial illness burden, low perceived quality of life and poor outcome, suggesting an unmet treatment need in TRD care in Italy. Registration Number: ClinicalTrials.gov, number: NCT03373253.

Simultaneous Measurement of Glomerular Filtration Rate, Effective Renal Plasma Flow and Tubular Secretion in Different Poultry Species by Single Intravenous Bolus of Iohexol and Para-Aminohippuric Acid.

The aim of the current study was to investigate the simultaneous measurement of plasma p-aminohippuric acid (PAH) clearance as a potential marker to assess effective renal plasma flow (eRPF) and tubular secretion (TS), and the plasma clearance of iohexol (IOH) as a marker of the glomerular filtration rate in poultry species. The PAH was administered intravenously (IV) to broiler chickens, layers, turkeys, Muscovy ducks, and pigeons. Each animal received successively a single bolus dose of 10 mg PAH/kg bodyweight (BW) and 100 mg PAH/kg BW to assess the eRPF and TS, respectively. Simultaneously with both PAH administrations, a single IV bolus of 64.7 mg/kg BW of IOH was administered. A high linear correlation (R2 = 0.79) between eRPF, based on the clearance of the low dose of PAH, and BW was observed for the poultry species. The correlation between TS, based on the clearance of the high dose of PAH, and BW was moderate (R2 = 0.50). Finally, a moderate correlation (R2 = 0.68) was demonstrated between GFR and eRPF and between GFR and TS (R2 = 0.56). This presented pharmacokinetic approach of the simultaneous administration of IOH and PAH enabled a simultaneous evaluation of eRPF/TS and GFR, respectively, in different poultry species.

Cue-Evoked Dopamine Promotes Conditioned Responding during Learning.

Dopamine neurons mediate the association of conditioned stimuli (CS) with reward (unconditioned stimuli, US) by signaling the discrepancy between predicted and actual reward during the US. Some theoretical models suggest that learning is also influenced by the salience or associability of the CS. A hallmark of CS associability models is that they can explain latent inhibition, i.e., the observation that novel CS are more effectively learned than familiar CS. Novel CS are known to activate dopamine neurons, but whether those responses affect associative learning has not been investigated. Here, we used fiber photometry to characterize dopamine responses to inconsequential familiar and novel stimuli. Using bidirectional optogenetic modulation during conditioning, we then show that CS-evoked dopamine promotes conditioned responses. This suggests that Pavlovian conditioning is influenced by CS dopamine, in addition to US reward prediction errors. Accordingly, the absence of dopamine responses to familiar CS might explain their slower learning in latent inhibition.

Development of an in Vivo Lipopolysaccharide Inflammation Model to Study the Pharmacodynamics of COX-2 Inhibitors Celecoxib, Mavacoxib, and Meloxicam in Cockatiels (Nymphicus hollandicus).

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used frequently in avian medicine for their antipyretic, analgesic, and anti-inflammatory properties during surgery and for diseases that cause tissue damage and inflammation. NSAIDs inhibit cyclooxygenase (COX) enzymes, which are responsible for the induction of pyresis, pain, and inflammation. In our study, a lipopolysaccharide-induced (LPS) pyresis model was optimized using cockatiels (Nymphicus hollandicus) as subject birds (four males/three females) and validated in two females and one male, characterized by an intravenous bolus injection of LPS (7.5 mg/kg) administered at T0 and T24 (24 hours following the first LPS injection). To demonstrate the feasibility of the model to assess pharmacodynamic (PD) parameters of different NSAIDs, mavacoxib 4 mg/kg (four males/four females), celecoxib 10 mg/kg (four males/four females) and meloxicam 1 mg/kg (four males/four females) were evaluated in the model at dosages used frequently in practice. The PD parameters (body temperature, mentation, posture, preference of location in the cage, and prostaglandin E2 [PGE2] plasma concentrations) were determined for 10 hours following the second LPS injection. At the doses evaluated, mavacoxib and celecoxib significantly reduced LPS-induced hypothermia, but had no clear effects on other clinical signs of illness. In contrast, no effect on hypothermia or clinical appearance was observed in the LPS-challenged cockatiels treated with meloxicam. All three NSAIDs were able to inhibit the increase in LPS-induced PGE2 plasma concentrations, yet the effect was most pronounced in the birds treated with meloxicam. Consequently, the presented model opens perspectives for future dose-effect PD studies to optimize analgesic protocols in cockatiels.

Dopamine neurons coding prediction errors in reward space, but not in aversive space: a matter of location?

Dopamine midbrain neurons are well known for prediction error coding in a reward context. A recent report by Christopher Fiorillo (Science 341: 546-549, 2013), however, suggests that these neurons behave markedly different when subjects get confronted with aversive, rather than appetitive, stimuli. Despite his findings being in line with indications of appetitive and aversive stimuli being processed by distinct neurotransmitter systems, they should still be interpreted with some caution due to a potential issue of recording location.

Glial cells in adult neurogenesis.

Adult neurogenesis is an exceptional feature of the adult brain and in an intriguing way bridges between neuronal and glial neurobiology. Essentially, all classes of glial cells are directly or indirectly linked to this process. Cells with astrocytic features, for example, serve as radial glia-like stem cells in the two neurogenic regions of the adult brain, the hippocampal dentate gyrus and the subventricular zone of the lateral ventricles, producing new neurons, create a microenvironment permissive for neurogenesis, and are themselves generated alongside the new neurons in an associated but independently regulated process. Oligodendrocytes are generated from precursor cells intermingled with those generating neurons in an independent lineage. NG2 cells have certain precursor cell properties and are found throughout the brain parenchyma. They respond to extrinsic stimuli and injury but do not generate neurons even though they can express some preneuronal markers. Microglia have positive and negative regulatory effects as constituents of the "neurogenic niche". Ependymal cells play incompletely understood roles in adult neurogenesis, but under certain conditions might exert (back-up) precursor cell functions. Glial contributions to adult neurogenesis can be direct or indirect and are mediated by mechanisms ranging from gap-junctional to paracrine and endocrine. As the two neurogenic regions differ between each other and both from the non-neurogenic rest of the brain, the question arises in how far regionalization of both the glia-like precursor cells as well as of the glial cells determines site-specific "neurogenic permissiveness." In any case, however, "neurogenesis" appears to be an essentially glial achievement.