Addition of an NK1 receptor antagonist to an SSRI did not enhance the antidepressant effects of SSRI monotherapy: results from a randomized clinical trial in patients with major depressive disorder

The Role of Substance P Within Traumatic Brain Injury and Implications for Therapy

This review examines the role of the neuropeptide substance P within the neuroinflammation that follows traumatic brain injury. It examines it in reference to its preferential receptor, the neurokinin-1 receptor, and explores the evidence for antagonism of this receptor in traumatic brain injury with therapeutic intent. Expression of substance P increases following traumatic brain injury. Subsequent binding to the neurokinin-1 receptor results in neurogenic inflammation, a cause of deleterious secondary effects that include an increased intracranial pressure and poor clinical outcome. In several animal models of TBI, neurokinin-1 receptor antagonism has been shown to reduce brain edema and the resultant rise in intracranial pressure. A brief overview of the history of substance P is presented, alongside an exploration into the chemistry of the neuropeptide with a relevance to its functions within the central nervous system. This review summarizes the scientific and clinical rationale for substance P antagonism as a promising therapy for human TBI.

Selective serotonin reuptake inhibitors are still harmful and ineffective. Responses to the comments by Hieronymus et al

In this response, we address point by point the additional issues raised by Hieronymus et al. in their second round of critique of our systematic review on selective serotonin reuptake inhibitors for major depression. We repulse that we are biased or mistaken in any major ways. We acknowledge that we missed a few small, mostly unpublished trials, and we made a few minor errors in our systematic review. However, these omissions and errors neither have any impact on our overall results nor on our conclusions. The critique by Hieronymus et al. seems to raise questions about their understanding of the systematic review process, and, on several occasions, they wrongly claimed that we made errors. Our analyses should be impartial and free from any biases or prejudices as we do not have any obligation to support the interests of sponsors or other groups.

Brain neurokinin-1 receptor availability in never-medicated patients with major depression - A pilot study

BACKGROUND

Neurotransmitter substance P (SP) and its preferred neurokinin-1 receptor (NK1R) have been implicated in the treatment of affective and addiction disorders. Despite promising preclinical data on antidepressant action, the clinical trials of NK1R antagonists in major depression have been disappointing. There are no direct in vivo imaging studies on NK1R characteristics in patients with a major depressive disorder (MDD).

METHODS

In this cross-sectional case-control study, we recruited nine never-medicated patients with moderate to severe MDD and nine matched healthy controls. NK1R availability (NK1R binding potential, BP_ND) was measured with in vivo 3-D positron emission tomography and a specific NK1 receptor tracer [¹⁸F]SPA-RQ. Clinical symptoms were assessed with the 17-item Hamilton Rating Scale for Depression (HAM-D17).

RESULTS

NK1R-BP_ND did not differ statistically significantly between patients with MDD and healthy controls. HAM-D17 total scores (range 21-32) correlated positively with NK1R-BP_ND in cortical and limbic areas. HAM-D17 subscale score for anxiety symptoms correlated positively with NK1R-BP_ND in specific brain areas implicated in fear and anxiety.

LIMITATIONS

Small sample size. Low variability in the clinical HAM-D subscale ratings may affect the observed correlations.

CONCLUSIONS

Our preliminary results do not support a different baseline expression of NK1Rs in a representative sample of never-medicated patients with MDD during a current moderate/severe depressive episode. The modulatory effect of NK1Rs on affective symptoms is in line with early positive results on antidepressant action of NK1 antagonists. However, the effect is likely to be too weak for treatment of MDD with NK1R antagonists alone in clinical practice.

Multiple possible inaccuracies cast doubt on a recent report suggesting selective serotonin reuptake inhibitors to be toxic and ineffective

According to a systematic review on the use of selective serotonin reuptake inhibitors (SSRIs) in adult depression that was recently published in BMC Psychiatry, the results of which have been widely disseminated in lay media, these drugs increase the risk for serious adverse events (SAEs) while exerting poor antidepressant efficacy. A cursory analysis, however, suggests the analysis of SAEs conducted by the authors to be marred by both methodological inaccuracies and blatant errors. After having corrected for these apparent mistakes, we conducted a sensitivity analysis in which we also accounted for a possible moderating effect of age; while this suggests SSRIs to be safe drugs in the non-elderly, they do confirm what is already known, that is, that they may enhance the risk for SAEs in the old. Given the loose definition of SAE, including also innocuous phenomena, the possible clinical significance of the latter observation, however, remains unclear until the nature and actual impact of the SAEs in question have been clarified. Moreover, with respect to efficacy, we find the paper in BMC Psychiatry misleading: first, the authors seem unaware of the well-established shortcomings associated with the conventional efficacy parameter on which their analysis is based, second, they have included suboptimal SSRI doses and third, they have missed some pivotal trials. Unless there are explanations for the many peculiarities in this paper that have escaped us, and which may be satisfactorily clarified by the authors, it seems important that the conclusions presented in this paper be publicly rectified.

Katakam and co-workers have not shown SSRIs to be harmful and ineffective and should stop claiming that they have

Funded by the Danish state to provide guidance in health-related matters, the Copenhagen Trial Unit (CTU) at Rigshospitalet may cause considerable societal harm if allowing their analyses to be influenced by bias and prejudice rather than rigor and impartiality. This is why we found it worthwhile to comment on a report from the CTU in which the authors invoked analyses marred by numerous errors and methodological mistakes to claim that selective serotonin reuptake inhibitors (SSRIs) are harmful and ineffective. The CTU group has now produced a response to our comment which is on par with their original contribution in terms of bias, misconceptions and mistakes. Our conclusion is that the reputation of the CTU would be best served by the authors asking for retraction of their SSRI paper.

Great boast, small roast on effects of selective serotonin reuptake inhibitors: response to a critique of our systematic review

Our systematic review in BMC Psychiatry concluded that selective serotonin reuptake inhibitors (SSRIs) compared with placebo significantly increase the risk of serious adverse events (SAEs) in patients with major depression and the potential beneficial effects of SSRIs seem to be outweighed by the harms. Hieronymus et al. accused us of methodological inaccuracies and blatant errors. In their post-hoc analysis of our data, they reported that SSRIs only increase the risk of SAEs in elderly and seems safe for non-elderly patients. They also found our review misleading because our efficacy analyses were based on the 17-item Hamilton Depression Rating Scale; we included suboptimal SSRI doses; and we missed some 'pivotal trials'. We do not agree with Hieronymus et al. regarding several of the 'errors' they claim that we have made. However, we acknowledge that they have identified minor errors and that we missed some trials. After rectifying the errors and inclusion of the missed trials by us and Hieronymus et al., we re-analysed the data. The updated analyses are even more robust and confirm our earlier conclusions. SSRIs significantly increase the risk of an SAE both in non-elderly (p=0.045) and elderly (p=0.01) patients [overall odds ratio 1.39; 95% confidence interval (CI) 1.13 to 1.73; p=0.002; I2=0%]. Moreover, SSRIs did not change noticeably the 17-item Hamilton Depression Rating Scale, the internationally accepted scale (mean difference -2.02 points; 95% CI -2.38 to -1.66; p<0.00001). We found no differential effect of dose (p=0.20).

Aprepitant and fosaprepitant drug interactions: a systematic review

AIMS

Aprepitant and fosaprepitant, commonly used for the prevention of chemotherapy-induced nausea and vomiting, alter cytochrome P450 activity. This systematic review evaluates clinically significant pharmacokinetic drug interactions with aprepitant and fosaprepitant and describes adverse events ascribed to drug interactions with aprepitant or fosaprepitant.

METHODS

We systematically reviewed the literature to September 11, 2016, to identify articles evaluating drug interactions involving aprepitant/fosaprepitant. The clinical significance of each reported pharmacokinetic drug interaction was evaluated based on the United States Food and Drug Administration guidance document on conducting drug interaction studies. The probability of an adverse event reported in case reports being due to a drug interaction with aprepitant/fosaprepitant was determined using the Drug Interaction Probability Scale.

RESULTS

A total of 4377 publications were identified. Of these, 64 met inclusion eligibility criteria: 34 described pharmacokinetic drug interactions and 30 described adverse events ascribed to a drug interaction. Clinically significant pharmacokinetic interactions between aprepitant/fosaprepitant and bosutinib PO, cabazitaxel IV, cyclophosphamide IV, dexamethasone PO, methylprednisolone IV, midazolam PO/IV, oxycodone PO and tolbutamide PO were identified, as were adverse events resulting from an interaction between aprepitant/fosaprepitant and alcohol, anthracyclines, ifosfamide, oxycodone, quetiapine, selective serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitors and warfarin.

CONCLUSIONS

The potential for a drug interaction with aprepitant and fosaprepitant should be considered when selecting antiemetic therapy.

New targets for rapid antidepressant action

Current therapeutic options for major depressive disorder (MDD) and bipolar disorder (BD) are associated with a lag of onset that can prolong distress and impairment for patients, and their antidepressant efficacy is often limited. All currently approved antidepressant medications for MDD act primarily through monoaminergic mechanisms. Glutamate is the major excitatory neurotransmitter in the central nervous system, and glutamate and its cognate receptors are implicated in the pathophysiology of MDD, and in the development of novel therapeutics for this disorder. The rapid and robust antidepressant effects of the N-methyl-d-aspartate (NMDA) antagonist ketamine were first observed in 2000. Since then, other NMDA receptor antagonists have been studied in MDD. Most have demonstrated relatively modest antidepressant effects compared to ketamine, but some have shown more favorable characteristics. This article reviews the clinical evidence supporting the use of novel glutamate receptor modulators with direct affinity for cognate receptors: (1) non-competitive NMDA receptor antagonists (ketamine, memantine, dextromethorphan, AZD6765); (2) subunit (GluN2B)-specific NMDA receptor antagonists (CP-101,606/traxoprodil, MK-0657); (3) NMDA receptor glycine-site partial agonists (GLYX-13); and (4) metabotropic glutamate receptor (mGluR) modulators (AZD2066, RO4917523/basimglurant). We also briefly discuss several other theoretical glutamate receptor targets with preclinical antidepressant-like efficacy that have yet to be studied clinically; these include α-amino-3-hydroxyl-5-methyl-4-isoxazoleproprionic acid (AMPA) agonists and mGluR2/3 negative allosteric modulators. The review also discusses other promising, non-glutamatergic targets for potential rapid antidepressant effects, including the cholinergic system (scopolamine), the opioid system (ALKS-5461), corticotropin releasing factor (CRF) receptor antagonists (CP-316,311), and others.

Selective serotonin reuptake inhibitors versus placebo in patients with major depressive disorder. A systematic review with meta-analysis and Trial Sequential Analysis

BACKGROUND

The evidence on selective serotonin reuptake inhibitors (SSRIs) for major depressive disorder is unclear.

METHODS

Our objective was to conduct a systematic review assessing the effects of SSRIs versus placebo, 'active' placebo, or no intervention in adult participants with major depressive disorder. We searched for eligible randomised clinical trials in The Cochrane Library's CENTRAL, PubMed, EMBASE, PsycLIT, PsycINFO, Science Citation Index Expanded, clinical trial registers of Europe and USA, websites of pharmaceutical companies, the U.S. Food and Drug Administration (FDA), and the European Medicines Agency until January 2016. All data were extracted by at least two independent investigators. We used Cochrane systematic review methodology, Trial Sequential Analysis, and calculation of Bayes factor. An eight-step procedure was followed to assess if thresholds for statistical and clinical significance were crossed. Primary outcomes were reduction of depressive symptoms, remission, and adverse events. Secondary outcomes were suicides, suicide attempts, suicide ideation, and quality of life.

RESULTS

A total of 131 randomised placebo-controlled trials enrolling a total of 27,422 participants were included. None of the trials used 'active' placebo or no intervention as control intervention. All trials had high risk of bias. SSRIs significantly reduced the Hamilton Depression Rating Scale (HDRS) at end of treatment (mean difference -1.94 HDRS points; 95% CI -2.50 to -1.37; P < 0.00001; 49 trials; Trial Sequential Analysis-adjusted CI -2.70 to -1.18); Bayes factor below predefined threshold (2.01*10-23). The effect estimate, however, was below our predefined threshold for clinical significance of 3 HDRS points. SSRIs significantly decreased the risk of no remission (RR 0.88; 95% CI 0.84 to 0.91; P < 0.00001; 34 trials; Trial Sequential Analysis adjusted CI 0.83 to 0.92); Bayes factor (1426.81) did not confirm the effect). SSRIs significantly increased the risks of serious adverse events (OR 1.37; 95% CI 1.08 to 1.75; P = 0.009; 44 trials; Trial Sequential Analysis-adjusted CI 1.03 to 1.89). This corresponds to 31/1000 SSRI participants will experience a serious adverse event compared with 22/1000 control participants. SSRIs also significantly increased the number of non-serious adverse events. There were almost no data on suicidal behaviour, quality of life, and long-term effects.

CONCLUSIONS

SSRIs might have statistically significant effects on depressive symptoms, but all trials were at high risk of bias and the clinical significance seems questionable. SSRIs significantly increase the risk of both serious and non-serious adverse events. The potential small beneficial effects seem to be outweighed by harmful effects.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42013004420.

CNS Target Identification and Validation: Avoiding the Valley of Death or Naive Optimism?

There are many challenges along the path to the approval of new drugs to treat CNS disorders, one of the greatest areas of unmet medical need with a large societal burden and health-care impact. Unfortunately, over the past two decades, few CNS drug approvals have succeeded, leading many pharmaceutical companies to deprioritize this therapeutic area. The reasons for the failures in CNS drug discovery are likely to be multifactorial. However, selecting the most biologically plausible molecular targets that are relevant to the disorder is a critical first step to improve the probability of success. In this review, we outline previous methods for identifying and validating novel targets for CNS drug discovery, and, cognizant of previous failures, we discuss potential new strategies that may improve the probability of success of developing novel treatments for CNS disorders.