Optimizing dosing of the cycloserine pro-drug terizidone in children with rifampicin-resistant tuberculosis

There are no pharmacokinetic data in children on terizidone, a pro-drug of cycloserine and a World Health Organization (WHO)-recommended group B drug for rifampicin-resistant tuberculosis (RR-TB) treatment. We collected pharmacokinetic data in children <15 years routinely receiving 15-20 mg/kg of daily terizidone for RR-TB treatment. We developed a population pharmacokinetic model of cycloserine assuming a 2-to-1 molecular ratio between terizidone and cycloserine. We included 107 children with median (interquartile range) age and weight of 3.33 (1.55, 5.07) years and 13.0 (10.1, 17.0) kg, respectively. The pharmacokinetics of cycloserine was described with a one-compartment model with first-order elimination and parallel transit compartment absorption. Allometric scaling using fat-free mass best accounted for the effect of body size, and clearance displayed maturation with age. The clearance in a typical 13 kg child was estimated at 0.474 L/h. The mean absorption transit time when capsules were opened and administered as powder was significantly faster compared to when capsules were swallowed whole (10.1 vs 72.6 min) but with no effect on bioavailability. Lower bioavailability (-16%) was observed in children with weight-for-age z-score below -2. Compared to adults given 500 mg daily terizidone, 2022 WHO-recommended pediatric doses result in lower exposures in weight bands 3-10 kg and 36-46 kg. We developed a population pharmacokinetic model in children for cycloserine dosed as terizidone and characterized the effects of body size, age, formulation manipulation, and underweight-for-age. With current terizidone dosing, pediatric cycloserine exposures are lower than adult values for several weight groups. New optimized dosing is suggested for prospective evaluation.

NRX-101, a Rapid-Acting Anti-Depressant, Does Not Cause Neurotoxicity Following Ketamine Administration in Preclinical Models

Agents that act at the N-methyl-D-aspartate receptor (NMDAR), such as ketamine, have gained increasing attention as rapid-acting antidepressants; however, their use has been limited by potential neurotoxicity. Recent FDA guidance requires a demonstration of safety on histologic parameters prior to the initiation of human studies. D-cycloserine (DCS) is a partial NMDA agonist that, along with lurasidone, is being investigated as a treatment for depression. The current study was designed to investigate the neurologic safety profile of DCS. To this end, female Sprague Dawley rats (n = 106) were randomly divided into 8 study groups. Ketamine was administered via tail vein infusion. DCS and lurasidone were administered via oral gavage in escalating doses to a maximum of 2000 mg/kg DCS. To ascertain toxicity, dose escalation with 3 different doses of D-cycloserine/lurasidone was given in combination with ketamine. MK-801, a known neurotoxic NMDA antagonist, was administered as a positive control. Brain tissue was sectioned and stained with H&E, silver, and Fluoro-Jade B stains. No fatalities were observed in any group. No microscopic abnormalities were found in the brain of animal subjects given ketamine, ketamine followed by DCS/lurasidone, or DCS/lurasidone alone. Neuronal necrosis, as expected, was seen in the MK-801 (positive control) group. We conclude that NRX-101, a fixed-dose combination of DCS/lurasidone, when administered with or without prior infusion of IV ketamine was tolerated and did not induce neurotoxicity, even at supratherapeutic doses of DCS.

Brain activity measured by functional brain imaging predicts breathlessness improvement during pulmonary rehabilitation

BACKGROUND

Chronic breathlessness in chronic obstructive pulmonary disease (COPD) is effectively treated with pulmonary rehabilitation. However, baseline patient characteristics predicting improvements in breathlessness are unknown. This knowledge may provide better understanding of the mechanisms engaged in treating breathlessness and help to individualise therapy. Increasing evidence supports the role of expectation (ie, placebo and nocebo effects) in breathlessness perception. In this study, we tested functional brain imaging markers of breathlessness expectation as predictors of therapeutic response to pulmonary rehabilitation, and asked whether D-cycloserine, a brain-active drug known to influence expectation mechanisms, modulated any predictive model.

METHODS

Data from 71 participants with mild-to-moderate COPD recruited to a randomised double-blind controlled experimental medicine study of D-cycloserine given during pulmonary rehabilitation were analysed (ID: NCT01985750). Baseline variables, including brain-activity, self-report questionnaires responses, clinical measures of respiratory function and drug allocation were used to train machine-learning models to predict the outcome, a minimally clinically relevant change in the Dyspnoea-12 score.

RESULTS

Only models that included brain imaging markers of breathlessness-expectation successfully predicted improvements in Dyspnoea-12 score (sensitivity 0.88, specificity 0.77). D-cycloserine was independently associated with breathlessness improvement. Models that included only questionnaires and clinical measures did not predict outcome (sensitivity 0.68, specificity 0.2).

CONCLUSIONS

Brain activity to breathlessness related cues is a strong predictor of clinical improvement in breathlessness over pulmonary rehabilitation. This implies that expectation is key in breathlessness perception. Manipulation of the brain's expectation pathways (either pharmacological or non-pharmacological) therefore merits further testing in the treatment of chronic breathlessness.

Using pre-treatment de novo threat conditioning outcomes to predict treatment response to DCS augmentation of exposure-based CBT

BACKGROUND

Over a decade and a half of research has resulted in inconsistent evidence for the efficacy of d-cycloserine (DCS), a partial glutamatergic N-methyl-D-aspartate agonist, for augmenting exposure-based cognitive behavioral therapy (CBT) for anxiety- and fear-based disorders. These variable findings have motivated the search for moderators of DCS augmentation efficacy.

METHODS

In this secondary analysis of a previous randomized clinical trial, we evaluated the value of de novo threat conditioning outcomes-degree of threat acquisition, extinction, and extinction retention-for predicting treatment response to exposure-based CBT for social anxiety disorder, applied with and without DCS augmentation in a sample of 59 outpatients.

RESULTS

We found that average differential skin conductance response (SCR) during extinction and extinction retention significantly moderated the prediction of clinical response to DCS: participants with poorer extinction and extinction retention showed relatively improved treatment response with DCS. No such effects were found for expectancy ratings, consistent with accounts of DCS selectively aiding lower-order but not higher-order extinction learning.

CONCLUSIONS

These findings provide support for extinction and extinction retention outcomes from threat conditioning as potential pre-treatment biomarkers for DCS augmentation benefits. Independent of DCS augmentation, the current study did not support threat conditioning outcomes as useful for predicting response to exposure-based CBT.

Population Pharmacokinetics and Dose Evaluation of Cycloserine among Patients with Multidrug-Resistant Tuberculosis under Standardized Treatment Regimens

Although cycloserine is a recommended drug for the treatment of multidrug-resistant tuberculosis (MDR-TB) according to World Health Organization (WHO), few studies have reported on pharmacokinetics (PK) and/or pharmacodynamics (PD) data of cycloserine in patients with standardized MDR-TB treatment. This study aimed to estimate the population PK parameters for cycloserine and to identify clinically relevant PK/PD thresholds, as well as to evaluate the current recommended dosage. Data from a large cohort with full PK curves was used to develop a population PK model. This model was used to estimate drug exposure in patients with MDR-TB from a multicentre prospective study in China. The classification and regression tree was used to identify the clinically relevant PK/PD thresholds. Probability of target attainment was analyzed to evaluate the currently recommended dosing strategy. Cycloserine was best described by a two-compartment disposition model. A percentage of time concentration above MICs (T>MIC) of 30% and a ratio of area under drug concentration-time curve (AUC0-24h) over MIC of 36 were the valid predictors for 6-month sputum culture conversion and final treatment outcome. Simulations showed that with WHO-recommended doses (500 mg and 750 mg for patients weighing <45 kg and ≥45 kg), the probability of target attainment exceeded 90% at MIC ≤16 mg/L in MGIT for both T>MIC of 30% and AUC0-24h/MIC of 36. New clinically relevant PK/PD thresholds for cycloserine were identified in patients with standardized MDR-TB treatment. WHO-recommended doses were considered adequate for the MGIT MIC distribution in our cohort of Chinese patients with MDR-TB.

Modeling cue-exposure therapy for alcohol use disorder in rhesus monkeys: Effects of putative cognitive enhancers

BACKGROUND

Cue-exposure therapy (CET) is an effective approach for anxiety-related disorders, but its effectiveness for substance use disorders is less clear. One potential means of improving CET outcomes is to include a cognitive-enhancing pharmacotherapy. This study evaluated d-cycloserine (DCS) and RY-023, putative cognitive enhancers targeting glutamate and GABA systems, respectively, in a monkey model of CET for alcohol use disorder.

METHODS

Male rhesus monkeys (n = 4) underwent multiple cycles of the CET procedure. During baseline (Phase 1), monkeys self-administered an ethanol solution under a fixed-ratio schedule and limited access conditions such that every 5th response in a 3-h session resulted in 30-s access to a drinking spout and a change in ethanol-paired cue lights from white to red. Behavior then was extinguished (Phase 2) by omitting the ethanol solution yet retaining the ethanol-paired stimulus lights. Monkeys also received injections of vehicle, DCS (3 mg/kg), a partial agonist at the glycine modulatory site on glutamatergic NMDA receptors, or the α5GABAA receptor-selective inverse agonist RY-023 (0.03 or 0.3 mg/kg). Once responding declined, monkeys underwent a cue reactivity test (Phase 3), and then returned to self-administration the following day to assess reacquisition (Phase 4).

RESULTS

Through multiple cycles, self-administration remained stable. Compared to vehicle, DCS facilitated extinction of ethanol seeking (Phase 2) and delayed reacquisition of ethanol self-administration (Phase 4). In contrast, RY-023 facilitated extinction (Phase 2) and reduced cue reactivity (Phase 3).

CONCLUSIONS

Adjunctive pharmacotherapy can improve CET outcomes, but the choice of pharmacotherapy should be dependent on the outcome of interest.

From Mouse to Man: N-Methyl-d-Aspartic Acid Receptor Activation as a Promising Pharmacotherapeutic Strategy for Autism Spectrum Disorders

The BALB/c mouse displays hypersensitivity to behavioral effects of MK-801 (dizocilpine), a noncompetitive N-methyl-d-aspartic acid (NMDA) receptor "open-channel" blocker, and shows both no preference for an enclosed stimulus mouse over an inanimate object and reduced social interaction with a freely behaving stimulus mouse. NMDA receptor agonist interventions improved measures of social preference and social interaction of the BALB/c mouse model of autism spectrum disorder (ASD). A "proof of principle/proof of concept" translational 10-week clinical trial with 8-week of active medication administration was conducted comparing 20 DSM-IV-TR-diagnosed older adolescent/young adult patients with ASD randomized to once-weekly pulsed administration (50 mg/d) versus daily administration of d-cycloserine (50 mg/d). The results showed that d-cycloserine, a partial glycine agonist, was well tolerated, the 2 dosing strategies did not differ, and improvement was noted on the "lethargy/social withdrawal" and "stereotypic behavior" subscales of the Aberrant Behavior Checklist. NMDA receptor activation contributes to the regulation of mTOR signaling, a pathologic point of convergence in several monogenic syndromic forms of ASD. Furthermore, both NMDA receptor hypofunction and imbalance between NMDA receptor activation mediated by GluN2B and GluN2A-containing NMDA receptors occur as "downstream" consequences of several genetically unrelated abnormalities associated with ASD. NMDA receptor-subtype selective "positive allosteric modulators (PAMs)" are particularly appealing medication candidates for future translational trials.

Efficacy of Adjunctive D-Cycloserine to Intermittent Theta-Burst Stimulation for Major Depressive Disorder: A Randomized Clinical Trial

Importance

The antidepressant effects of transcranial magnetic stimulation protocols for major depressive disorder (MDD) are thought to depend on synaptic plasticity. The theta-burst stimulation (TBS) protocol synaptic plasticity is known to be N-methyl-D-aspartate (NMDA)-receptor dependent, yet it is unknown whether enhancing NMDA-receptor signaling improves treatment outcomes in MDD.

Objective

To test whether low doses of the NMDA-receptor partial-agonist, D-cycloserine, would enhance intermittent TBS (iTBS) treatment outcomes in MDD.

Design, Setting, and Participants

This was a single-site 4-week, double-blind, placebo-controlled, randomized clinical trial conducted from November 6, 2019, to December 24, 2020, including 50 participants with MDD. Participants were recruited via advertisements and referral. Inclusion criteria were as follows: age 18 to 65 years with a primary diagnosis of MDD, a major depressive episode with score of 18 or more on the 17-item Hamilton Depression Rating Scale, a Young Mania Rating Scale score of 8 or less, and normal blood work (including complete blood cell count, electrolytes, liver function tests, and creatinine level).

Interventions

Participants were randomly assigned 1:1 to either iTBS plus placebo or iTBS plus D-cycloserine (100 mg) for the first 2 weeks followed by iTBS without an adjunct for weeks 3 and 4.

Main Outcomes and Measures

The primary outcome was change in depressive symptoms as measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) at the conclusion of treatment. Secondary outcomes included clinical response, clinical remission, and Clinical Global Impression (CGI) scores.

Results

A total of 50 participants (mean [SD] age, 40.8 [13.4] years; 31 female [62%]) were randomly assigned to treatment groups: iTBS plus placebo (mean [SD] baseline score, 30.3 [4.2]) and iTBS plus D-cycloserine (mean [SD] baseline score, 30.4 [4.5]). The iTBS plus D-cycloserine group had greater improvements in MADRS scores compared with the iTBS plus placebo group (mean difference, -6.15; 95% CI, -2.43 to -9.88; Hedges g = 0.99; 95% CI, 0.34-1.62). Rates of clinical response were higher in the iTBS plus D-cycloserine group than in the iTBS plus placebo group (73.9% vs 29.3%), as were rates of clinical remission (39.1% vs 4.2%). This was reflected in lower CGI-severity ratings and greater CGI-improvement ratings. No serious adverse events occurred.

Conclusions and Relevance

Findings from this clinical trial indicate that adjunctive D-cycloserine may be a promising strategy for enhancing transcranial magnetic stimulation treatment outcomes in MDD using iTBS requiring further investigation.

Trial Registration

ClinicalTrials.gov Identifier: NCT03937596.

Cycloserine and Linezolid for Tuberculosis Meningitis: Pharmacokinetic Evidence of Potential Usefulness

BACKGROUND

The ability of antituberculosis drugs to cross the blood-brain barrier and reach the central nervous system is critical to their effectiveness in treating tuberculosis meningitis (TBM). We sought to fill a critical knowledge gap by providing data on the ability of new and repurposed antituberculosis drugs to penetrate into the cerebrospinal fluid (CSF).

METHODS

We conducted a clinical pharmacology study among patients treated for TBM in Tbilisi, Georgia, from January 2019 until January 2020. Serial serum and CSF samples were collected while patients were hospitalized. CSF was collected from routine lumbar punctures with the timing of the lumbar puncture alternating between 2 and 6 hours to capture early and late CSF penetration.

RESULTS

A total of 17 patients treated for TBM (8 with confirmed disease) were included; all received linezolid, with a subset receiving cycloserine (5), clofazimine (5), delamanid (4), and bedaquiline (2). All CSF measurements of bedaquiline (12), clofazimine (24), and delamanid (19) were below the limit of detection. The median CSF concentrations of cycloserine at 2 and 6 hours were 15.90 and 15.10 µg/mL with adjusted CSF/serum ratios of 0.52 and 0.66. CSF concentrations of linezolid were 0.90 and 3.14 µg/mL at 2 and 6 hours, with adjusted CSF/serum ratios of 0.25 and 0.59, respectively. CSF serum linezolid concentrations were not affected by rifampin coadministration.

CONCLUSIONS

Based on moderate to high CSF penetration, linezolid and cycloserine may be effective drugs for TBM treatment, whereas the utility of bedaquiline, delamanid, and clofazimine is uncertain given their low CSF penetration.

Enhancing exposure therapy for posttraumatic stress disorder (PTSD): a randomized clinical trial of virtual reality and imaginal exposure with a cognitive enhancer

Posttraumatic stress disorder (PTSD) is a significant public health issue. Yet, there are limited treatment options and no data to suggest which treatment will work for whom. We tested the efficacy of virtual reality exposure (VRE) or prolonged imaginal exposure (PE), augmented with D-cycloserine (DCS) for combat-related PTSD. As an exploratory aim, we examined whether brain-derived neurotrophic factor (BDNF) and fatty acid amide hydrolase (FAAH) moderated treatment response. Military personnel with PTSD (n = 192) were recruited into a multisite double-blind randomized controlled trial to receive nine weeks of VRE or PE, with DCS or placebo. Primary outcome was the improvement in symptom severity. Randomization was stratified by comorbid depression (MDD) and site. Participants in both VRE and PE showed similar meaningful clinical improvement with no difference between the treatment groups. A significant interaction (p = 0.45) suggested VRE was more effective for depressed participants (CAPS difference M = 3.51 [95% CI 1.17-5.86], p = 0.004, ES = 0.14) while PE was more effective for nondepressed participants (M = -8.87 [95% CI -11.33 to -6.40], p < 0.001, ES = -0.44). The main effect of DCS vs. placebo was not significant. Augmentation by MDD interaction (p = 0.073) suggested that depressed participants improved more on placebo (M = -8.43 [95% CI -10.98 to -5.88], p < 0.001, ES = -0.42); DCS and placebo were equally effective for nondepressed participants. There was an apparent moderating effect of BDNF Val66Met polymorphism on DCS augmentation (ES = 0.67). Met66 allele carriers improved more on DCS (ES = -0.25). FAAH 385 A carriers improved more than non-carriers (ES = 0.33), particularly those with MDD (ES = 0.62). This study provides a step toward precision therapeutics for PTSD by demonstrating that comorbid MDD and genetic markers may help guide treatment selection.ClinicalTrials.gov Identifier: NCT01352637.

D-cycloserine normalizes long-term motor plasticity after transcranial magnetic intermittent theta-burst stimulation in major depressive disorder

OBJECTIVES

Major Depressive Disorder (MDD) is associated with glutamatergic alterations, including the N-methyl-D-aspartate receptor (NMDA-R). The NMDA-R plays an important role in synaptic plasticity, and individuals with MDD have been shown to have impairments in repetitive Transcranial Magnetic Stimulation (rTMS) motor plasticity. Here, we test whether D-cycloserine, a NMDA-R partial agonist, can rescue TMS motor plasticity in MDD.

METHODS

We conducted randomized double-blind placebo-controlled crossover studies in healthy (n = 12) and MDD (n = 12) participants. We stimulated motor cortex using TMS intermittent theta burst stimulation (iTBS) with placebo or D-cycloserine (100 mg). Motor evoked potentials (MEPs) were sampled before and after iTBS. Stimulus response curves (SRC) were characterized at baseline, +90 minutes, and the following day.

RESULTS

Acute iTBS MEP facilitation is reduced in MDD and is not rescued by D-cycloserine. After iTBS, SRCs shift to indicate sustained decrease in excitability in healthy participants, yet increased in excitability in MDD participants. D-cycloserine normalized SRC changes from baseline to the following day in MDD participants. In both healthy and MDD participants, D-cycloserine stabilized changes in SRC.

CONCLUSION

MDD is associated with alterations in motor plasticity that are rescued and stabilized by NMDA-R agonism.

SIGNIFICANCE

Agonism of NMDA receptors rescues iTBS motor plasticity in MDD.

The effectiveness and adverse effects of D-cycloserine compared with placebo on social and communication skills in individuals with autism spectrum disorder

BACKGROUND

Symptoms of autism spectrum disorder (ASD) have been associated, in part, with the dysfunction of N-methyl-D-aspartate (NMDA) glutamate receptors at excitatory synapses and glutamate abnormalities. Medications related to glutamatergic neurotransmission, such as D-cycloserine - which is a partial agonist of the NMDA glutamate receptor - are potential treatment options for the core features of ASD. However, the potential effect of D-cycloserine on the social and communication skills deficits of individuals with ASD has not been thoroughly explored and no systematic reviews of the evidence have been conducted.

OBJECTIVES

To assess the efficacy and adverse effects of D-cycloserine compared with placebo for social and communication skills in individuals with ASD.

SEARCH METHODS

In November 2020, we searched CENTRAL, MEDLINE, Embase, six other databases and two trials registers. We also searched the reference lists of relevant publications and contacted the authors of the included study, Minshawi 2016, to identify any additional studies. In addition, we contacted pharmaceutical companies, searched manufacturers' websites and sources of reports of adverse events.  SELECTION CRITERIA: All randomised controlled trials (RCTs) of any duration and dose of D-cycloserine, with or without adjunct treatment, compared to placebo in individuals with ASD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted relevant data, assessed the risk of bias, graded the certainty of the evidence using the GRADE approach, and analysed and evaluated the data. We provide a narrative report of the findings as only one study is included in this review.

MAIN RESULTS

We included a single RCT (Minshawi 2016) funded by the United States Department of Defense. It was conducted at two sites in the USA: Indiana University School of Medicine and Cincinnati Children's Hospital Medical Centre. In the included study, 67 children with ASD aged between 5 and 11 years were randomised to receive either 10 weeks (10 doses) of (50 mg) D-cycloserine plus social skills training, or placebo plus social skills training. Randomisation was carried out 1:1 between D-cycloserine and placebo arms, and outcome measures were recorded at one-week post-treatment. The 'risk of bias' assessment for the included study was low for five domains and unclear for two domains. The study (67 participants) reported low certainty evidence of little to no difference between the two groups for all outcomes measured at one week post-treatment: social interaction impairment (mean difference (MD) 3.61 (assessed with the Social Responsiveness Scale), 95% confidence interval (CI) -5.60 to 12.82); social communication impairment (MD -1.08 (measured using the inappropriate speech subscale of the Aberrant Behavior Checklist (ABC)), 95% CI -2.34 to 0.18); restricted, repetitive, stereotyped patterns of behaviour (MD 0.12 (measured by the ABC stereotypy subscale), 95% CI -1.71 to 1.95); serious adverse events (risk ratio (RR) 1.11, 95% CI 0.94 to 1.31); non-core symptoms of ASD (RR 0.97 (measured by the Clinical Global Impression-Improvement scale), 95% CI 0.49 to 1.93); and tolerability of D-cycloserine (RR 0.32 (assessed by the number of dropouts), 95% CI 0.01 to 7.68).  AUTHORS' CONCLUSIONS: We are unable to conclude with certainty whether D-cycloserine is effective for individuals with ASD. This review included low certainty data from only one study with methodological issues and imprecision. The added value of this review compared to the included study is we assessed the risk of bias and evaluated the certainty of evidence using the GRADE approach. Moreover, if we find new trials in future updates of this review, we could potentially pool the data, which may either strengthen or decrease the evidence for our findings.

Effect of D-Cycloserine on the Effect of Concentrated Exposure and Response Prevention in Difficult-to-Treat Obsessive-Compulsive Disorder: A Randomized Clinical Trial

IMPORTANCE

Evidence is lacking for viable treatment options for patients with difficult-to-treat obsessive-compulsive disorder (OCD). It has been suggested that D-cycloserine (DCS) could potentiate the effect of exposure and response prevention (ERP) treatment, but the hypothesis has not been tested among patients with difficult-to-treat OCD.

OBJECTIVE

To evaluate whether DCS potentiates the effect of concentrated ERP among patients with difficult-to-treat OCD.

DESIGN, SETTING, AND PARTICIPANTS

The study was a randomized placebo-controlled triple-masked study with a 12-month follow-up. Participants were adult outpatients with difficult-to-treat OCD. A total of 220 potential participants were referred, of whom 36 did not meet inclusion criteria and 21 declined to participate. Patients had either relapsed after (n = 100) or not responded to (n = 63) previous ERP treatment. A total of 9 specialized OCD teams within the public health care system in Norway participated, giving national coverage. An expert team of therapists from the coordinating site delivered treatment. Inclusion of patients started in January 2016 and ended in August 2017. Data analysis was conducted February to September 2019.

INTERVENTIONS

All patients received individual, concentrated ERP treatment delivered during 4 consecutive days in a group setting (the Bergen 4-day treatment format) combined with 100 mg DCS, 250 mg DCS, or placebo.

MAIN OUTCOMES AND MEASURES

Change in symptoms of OCD and change in diagnostic status. Secondary outcomes measures included self-reported symptoms of OCD, anxiety, depression, and quality of life.

RESULTS

The total sample of 163 patients had a mean (SD) age of 34.5 (10.9) years, and most were women (117 [71.8%]). They had experienced OCD for a mean (SD) of 16.2 (10.2) years. A total of 65 patients (39.9%) were randomized to receive 100 mg DCS, 67 (41.1%) to 250 mg of DCS, and 31 (19.0%) to placebo. Overall, 91 (56.5%) achieved remission at posttreatment, while 70 (47.9%) did so at the 12-month follow-up. There was no significant difference in remission rates among groups. There was a significant reduction in symptoms at 12 months, and within-group effect sizes ranged from 3.01 (95% CI, 2.38-3.63) for the group receiving 250 mg DCS to 3.49 (95% CI, 2.78-4.18) for the group receiving 100 mg DCS (all P < .001). However, there was no significant effect of treatment group compared with placebo in obsessive-compulsive symptoms (250 mg group at posttreatment: d = 0.33; 95% CI, -0.10 to 0.76; 100 mg group at posttreatment: d = 0.36; 95% CI, -0.08 to 0.79), symptoms of depression and anxiety (eg, Patient Health Questionnaire-9 score among 250 mg group at 12-month follow-up: d = 0.30; 95% CI, -0.17 to 0.76; Generalized Anxiety Disorder-7 score among 100 mg group at 12-month follow-up: d = 0.27; 95% CI, -0.19 to 0.73), and well-being (250 mg group: d = 0.10; 95% CI, -0.42 to 0.63; 100 mg group: d = 0.34; 95% CI, -0.19 to 0.86). No serious adverse effects were reported.

CONCLUSIONS AND RELEVANCE

In this study, DCS did not potentiate ERP treatment effect, but concentrated ERP treatment was associated with improvement.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02656342.

D-cycloserine augmentation of cognitive behavioral therapy for delusions: A randomized clinical trial

OBJECTIVE

D-cycloserine (DCS) promotes consolidation of extinction learning. This study extends earlier work by examining whether DCS can enhance cognitive behavioral therapy (CBT) for delusions.

METHODS

Adults reporting moderate or greater delusions were randomly assigned to receive 50 mg of DCS or placebo prior to 10 weekly CBT sessions. The primary outcome was change in severity of delusions measured with the Psychotic Symptom Rating Scale delusion subscale (PSYRATS-D). Secondary outcomes included persistence of response at 3 and 6 month follow-up and the effects of DCS on memory consolidation and cognitive flexibility. Fifty-eight participants were randomized and 44 completed the trial.

RESULTS

The DCS and placebo groups did not differ in change from baseline to end of CBT on PSYRATS-D, nor did DCS improve memory consolidation or cognitive flexibility compared to placebo. However, at the 3 month follow-up visit (week 24), 47% of participants who completed treatment with DCS reported a 20% or greater decrease on PSYRATS-D compared to 15% in the placebo group (p = .04). Change in distress across CBT sessions interacted with treatment group to predict change from baseline to week 24 in PSYRATS-D total score (p = .03) such that response at week 24 was greatest in DCS-treated participants who experienced a decrease in distress during CBT sessions.

CONCLUSIONS

DCS augmentation of CBT did not improve delusions compared to placebo during treatment; however, DCS was associated with a higher response rate at 3-month follow-up. DCS may produce a delayed therapeutic effect, associated with successful CBT sessions, but this finding requires replication.

Gitelman-like syndrome: A rare complication of using aminoglycosides in tuberculosis - A case report

Aminoglycosides are known to cause electrolyte disturbances. Approximately 8-26% of patients who receive an aminoglycoside for several days develop mild renal impairment that is almost always reversible (Brunton et al., 2013). A 46 year old male with multi-drug-resistant pulmonary tuberculosis with resistance to kanamycin is being presented, who was on injectable Capreomycin, Levofloxacin, Ethionamide, Cycloserine, pyrazinamide, linezolid and clofazamine for a period of four months. He presented to us with generalised weakness and pain in the lower limb muscles. Investigation revealed hypokalemia, metabolic alkalosis, hypomagnesemia, hypocalceuria and hypocalcemia. This features mimic Gitelman's syndrome which is an autosomal recessive disorder affecting kidneys causing electrolyte disturbances. The drug was immediately withdrawn and electrolyte correction was given and the condition reversed gradually.

Ethionamide induced blue vision (cyanopsia): Case report

Ethionamide is part of a group of drugs used in the treatment of drug resistant TB. With the advent of increasing drug resistance in pulmonary TB cases, use of Ethionamide, a second line anti tubercular drug is increasing. Vision changes are rare with ethionamide. Cyanopsia i.e., bluish tinted vision of surroundings with ethionamide is not known in literature. Here, we report a case of DRTB patient who developed cyanopsia soon after introducing ethionamide. Although reversible, ethionamide may sometimes need withdrawal because of significant distress caused to patient.

Dose Timing of D-Cycloserine to Augment Exposure Therapy for Social Anxiety Disorder: A Randomized Clinical Trial

IMPORTANCE

Findings suggest that the efficacy of D-cycloserine (DCS) for enhancing exposure therapy may be strongest when administered after sessions marked by low fear at the conclusion of exposure practice. These findings have prompted investigation of DCS dosing tailored to results of exposure sessions.

OBJECTIVE

To compare tailored postsession DCS administration with presession DCS administration, postsession DCS administration, and placebo augmentation of exposure therapy for social anxiety disorder.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind randomized clinical trial involved adults with social anxiety disorder enrolled at 3 US university centers. Symptom severity was assessed at baseline, weekly during treatment, and at 1-week and 3-month follow-up. Data analysis was performed from September 2019 to March 2020.

INTERVENTIONS

Participants completed a 5-session treatment and received pills commensurate with their condition assignment at sessions 2 through 5, which emphasized exposure practice.

MAIN OUTCOMES AND MEASURES

Symptom severity was evaluated by the Liebowitz Social Anxiety Scale and Social Phobic Disorders-Severity Form as administered by independent evaluators.

RESULTS

A total of 152 participants were enrolled (mean [SD] age, 29.24 [10.16] years; 84 men [55.26%]). Compared with placebo, presession and postsession conditions showed greater symptom improvement (b = -0.25; 95% CI, -0.37 to -0.13; P < .001; d = 1.07; and b = -0.20; 95% CI, -0.32 to -0.07; P = .002; d = 0.85) and lower symptom severity (b = -0.51; 95% CI, -0.81 to -0.21; P < .001; d = 0.76; and b = -0.49; 95% CI, -0.80 to -0.18; P = .002; d = 0.72) at 3-month follow-up. No differences were found between presession and postsession conditions. The tailored condition showed no advantage over placebo. Compared with the tailored condition, presession and postsession conditions evidenced greater decreases (b = -0.22; 95% CI, -0.34 to -0.10; P < .001; d = 0.94; and b = -0.17, 95% CI, -0.29 to -0.04; P = .008; d = 0.72) and lower symptom severity (b = -0.44, 95% CI, -0.73 to -0.14; P = .004; d = 0.64; and b = -0.41, 95% CI, -0.72 to -0.11; P = .008; d = 0.61) at 3-month follow-up.

CONCLUSIONS AND RELEVANCE

Administration of DCS enhanced exposure therapy for social anxiety disorder when given before or after the exposure session. However, the study failed to achieve the aim to develop a tailored clinical application.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02066792.

Changes in Dosing and Dose Timing of D-Cycloserine Explain Its Apparent Declining Efficacy for Augmenting Exposure Therapy for Anxiety-related Disorders: An Individual Participant-data Meta-analysis

The apparent efficacy of d-cycloserine (DCS) for enhancing exposure treatment for anxiety disorders appears to have declined over the past 14 years. We examined whether variations in how DCS has been administered can account for this "declining effect". We also investigated the association between DCS administration characteristics and treatment outcome to find optimal dosing parameters. We conducted a secondary analysis of individual participant data obtained from 1047 participants in 21 studies testing the efficacy of DCS-augmented exposure treatments. Different outcome measures in different studies were harmonized to a 0-100 scale. Intent-to-treat analyses showed that, in participants randomized to DCS augmentation (n = 523), fewer DCS doses, later timing of DCS dose, and lower baseline severity appear to account for this decline effect. More DCS doses were related to better outcomes, but this advantage leveled-off at nine doses. Administering DCS more than 60 minutes before exposures was also related to better outcomes. These predictors were not significant in the placebo arm (n = 521). Results suggested that optimal DCS administration could increase pre-to-follow-up DCS effect size by 50%. In conclusion, the apparent declining effectiveness of DCS over time may be accounted for by how it has been administered. Optimal DCS administration may substantially improve outcomes. Registration: The analysis plan for this manuscript was registered on Open Science Framework (https://osf.io/c39p8/).

Enhanced exposure therapy for combat-related Posttraumatic Stress Disorder (PTSD): Study protocol for a randomized controlled trial

BACKGROUND

PTSD, which has been identified in up to 23% of post-9-11 veterans, often results in a chronic, pernicious course. Thus, effective treatments are imperative. The Institute of Medicine (IOM) concluded that the only intervention for PTSD with sufficient evidence to conclude efficacy is exposure therapy. This Phase III trial compares the efficacy of exposure therapy for combat-related PTSD delivered in two different formats- via virtual reality exposure therapy (VRE) or prolonged exposure therapy (PE)- combined with D-Cycloserine (DCS), a cognitive enhancer shown to facilitate the extinction of fear.

METHODS/DESIGN

Military personnel of any duty status and civilians deployed to Iraq and Afghanistan were eligible. Participants were randomly assigned to 9 sessions of exposure therapy (VRE or PE) and medication (50 mg DCS or placebo). Participants were treated at three geographically diverse sites. Participants were re-assessed at 3-months post-treatment. The co-primary hypotheses are that (1) DCS will augment response to exposure therapy (both VRE and PE) on PTSD symptoms; (2) VRE will be associated with greater improvement than PE. Genetic and psychophysiological markers will be evaluated as potential moderators and mediators of treatment outcomes as well as secondary outcomes.

DISCUSSION

This study is the first to compare the relative efficacy of DCS-augmented VRE versus PE on PTSD symptoms. The design has several advantages: participants received an active, effective treatment and predictors of response to treatment included genetic and psychobiological measures. The results may directly influence the future delivery of services, and contribute to the development of a standardized treatment protocol.

TRIAL REGISTRATION

NCT01352637.

Effect of d-cycloserine on fear extinction training in adults with social anxiety disorder

Preclinical and clinical data have shown that D-cycloserine (DCS), a partial agonist at the N-methyl-d-aspartate receptor complex, augments the retention of fear extinction in animals and the therapeutic learning from exposure therapy in humans. However, studies with non-clinical human samples in de novo fear conditioning paradigms have demonstrated minimal to no benefit of DCS. The aim of this study was to evaluate the effects of DCS on the retention of extinction learning following de novo fear conditioning in a clinical sample. Eighty-one patients with social anxiety disorder were recruited and underwent a previously validated de novo fear conditioning and extinction paradigm over the course of three days. Of those, only 43 (53%) provided analyzable data. During conditioning on Day 1, participants viewed images of differently colored lamps, two of which were followed by with electric shock (CS+) and a third which was not (CS-). On Day 2, participants were randomly assigned to receive either 50 mg DCS or placebo, administered in a double-blind manner 1 hour prior to extinction training with a single CS+ in a distinct context. Day 3 consisted of tests of extinction recall and renewal. The primary outcome was skin conductance response to conditioned stimuli, and shock expectancy ratings were examined as a secondary outcome. Results showed greater skin conductance and expectancy ratings in response to the CS+ compared to CS- at the end of conditioning. As expected, this difference was no longer present at the end of extinction training, but returned at early recall and renewal phases on Day 3, showing evidence of return of fear. In contrast to hypotheses, DCS had no moderating influence on skin conductance response or expectancy of shock during recall or renewal phases. We did not find evidence of an effect of DCS on the retention of extinction learning in humans in this fear conditioning and extinction paradigm.

D-Cycloserine augmentation of cognitive behavior therapy for pediatric OCD: Predictors and moderators of outcome

BACKGROUND

Over half of children receiving cognitive behavioral therapy (CBT) for obsessive compulsive disorder (OCD) do not fully remit. To improve response rates and enhance extinction learning, d-cycloserine (DCS) has been examined as an augmenting agent of CBT. To direct children with OCD towards treatments with the highest likelihood of success, the current study evaluated the conditions under which DCS augmentation works best (i.e., moderators) and the baseline characteristics associated with outcome, irrespective of treatment type (i.e., predictors).

METHODS

Data came from a two-site randomized controlled trial (N = 142) in which children received either DCS + CBT (n = 70) or placebo + CBT.

RESULTS

No baseline variables moderated the effects of DCS augmentation on CBT outcome. However, several predictor variables were associated with a decreased likelihood of achieving remission status, including higher family accommodation scores, higher impairment scores, higher depression scores, and higher externalizing scores. Furthermore, better insight at pre-treatment was associated with more improvement longitudinally on a clinician-rated summary measure of illness severity.

LIMITATIONS

The current study did not examine all variables that had previously been shown to moderate or predict treatment outcome (e.g., family history of OCD or cognitive profile).

CONCLUSIONS

The absence of significant moderators suggests that baseline factors cannot yet be used to determine who benefits most from DCS. To maximize treatment benefits for children presenting with identified predictors of worse treatment outcome, clinicians might need to adapt existing CBT protocols and administer additional interventions that address patients' specific problem areas.

A selective and sensitive high performance liquid chromatography assay for the determination of cycloserine in human plasma

BACKGROUND

Cycloserine (CYC) is a second line antitubercular drug that is used for the treatment of multidrug resistant tuberculosis (MDR-TB) along with other antitubercular agents and is often used in developing countries. Monitoring CYC levels in plasma could be useful in the clinical management of patients with MDR-TB. A high performance liquid chromatography method for the determination of CYC in human plasma was developed.

METHODS

The method involved extraction of the sample using solid phase extraction cartridges and analysis of the extracted sample using a reverse phase T3 column (150mm) and detection at 240nm with Photo Diode Array (PDA) detector. The chromatogram was run for 15min at a flow rate of 0.4ml/min at 30°C.

RESULTS AND CONCLUSION

The assay was specific for CYC and linear from 5.0 to 50.0μg/ml. The relative standard deviations of within- and between-day assays were less than 10%. Recovery of CYC ranged from 102% to 109%. The interference of other second line anti-TB drugs in the assay of CYC was ruled out. The assay spans the concentration range of clinical interest. The specificity and sensitivity of this assay makes it highly suitable for pharmacokinetic studies.

D-Cycloserine Ameliorates Autism-Like Deficits by Removing GluA2-Containing AMPA Receptors in a Valproic Acid-Induced Rat Model

Valproic acid (VPA)-exposed rat offspring have demonstrated autism spectrum disorder (ASD) phenotypes and impaired N-methyl-D-aspartate receptor (NMDAR)-dependent long-term depression (LTD) in the lateral nucleus of the amygdala. NMDAR partial agonist _D-cycloserine (DCS) has been reported to act as a cognitive enhancer by increasing the NMDAR response to improve autistic-like phenotypes in animals. However, the mechanism of DCS in alleviating the ASD is still unknown. Using combined behavioral, electrophysiological, and molecular approaches, we found that DCS administration rescued social interaction deficits and anxiety/repetitive-like behaviors observed in VPA-exposed offspring. In the amygdala synapses, DCS treatment reversed the decreased paired pulse ratio (PPR) and the impaired NMDAR-dependent LTD, increased the frequency and amplitude of miniature excitatory post-synaptic currents (mEPSCs), and resulted in a higher dendritic spine density at the amygdala synapses in the VPA-exposed offspring. Moreover, we found that DCS facilitated the removal of GluA2-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (GluA2/AMPARs) by inducing NMDAR-dependent LTD in the VPA-exposed offspring. We further established that the effects of DCS treatment, including increased GluA2/AMPAR removal and rescues of impaired social behavior, were blocked by Tat-GluA2_3Y, a GluA2-derived peptide that disrupted regulation of AMPAR endocytosis. These results provided the first evidence that rescue of the ASD-like phenotype by DCS is mediated by the mechanism of GluA2/AMPAR removal in VPA-exposed rat offspring.

D-cycloserine augmentation of behavior therapy for anxiety and obsessive-compulsive disorders: A meta-analysis

OBJECTIVE

The present meta-analysis investigates whether the antibiotic D-cycloserine (DCS), a partial agonist at the glutamatergic N-methyl-D-aspartate receptor, can augment the effect of behavior therapy in humans with anxiety and obsessive-compulsive disorders.

METHOD

A keyword-based computer search was conducted using common electronic databases. Only studies investigating the effect of DCS in humans with anxiety and obsessive-compulsive disorders were included, resulting in 23 studies with a combined sample size of 1314 patients. Effect sizes were coded as Hedges' g and SMCC, the latter also incorporating differences in pre-treatment values. Bayesian multilevel meta-analysis was applied to take dependencies of effect sizes obtained from the same study into account.

RESULTS

While previous meta-analyses found small to moderate improvements, the current results including the most recent research indicate that the overall effect of DCS is very small and almost indistinguishable from zero (g = -0.12, CI = [-0.27, 0.02]; SMCC = -0.10, CI = [-0.29, 0.07]). Slightly larger effects were found for social anxious patients. Further, study quality and year of publication were relevant moderators, with higher quality / more recent studies reported smaller effects of DCS.

CONCLUSIONS

These findings raise the question of the usefulness of DCS as an augmentation of exposure therapy for anxiety and obsessive-compulsive disorders. At least, it seems to be less promising than initially thought. The fact that study quality was inversely related to the reported effect sizes underlines the importance of high quality primary research in order to avoid over-estimation of treatment effects in clinical psychology.

Treatment for Krabbe's disease: Finding the combination

Globoid cell leukodystrophy (GLD) is an autosomal recessive neurodegenerative disorder caused by a deficiency of the lysosomal enzyme galactocerebrosidase (GALC). GALC is responsible for catabolism of certain glycolipids, including the toxic compound galactosylsphingosine (psychosine). Histological signs of disease include the widespread loss of myelin in the central and peripheral nervous systems, profound neruroinflammation, and axonal degeneration. Patients suffering from GLD also display neurological deterioration. Many different individual therapies have been investigated in the murine model of the GLD, the Twitcher mouse, with minimal success. The current standard of care for GLD patients, hematopoietic stem cell transplantation, serves only to delay disease progression and is not an effective cure. However, combination therapies that target different pathogenic mechanisms/pathways have been more effective at reducing histological signs of disease, delaying disease onset, prolonging life span, and improving behavioral/cognitive functions in rodent models of Krabbe's disease. In some cases, dramatic synergy between the various therapies has been observed. © 2016 Wiley Periodicals, Inc.

Neuroinflammation-Induced Memory Deficits Are Amenable to Treatment with D-Cycloserine

Cognitive deficits, especially memory loss, are common following many types of brain insults which are associated with neuroinflammation, although the underlying mechanisms are not entirely clear. The present study aimed to characterize the long-term cognitive and behavioral impairments in a mouse model of neuroinflammation in the absence of other insults and to evaluate the therapeutic potential of D-cycloserine (DCS). DCS is a co-agonist of the NMDA receptor that ameliorates cognitive deficits in models of TBI and stroke. Using a mouse model of global neuroinflammation induced by intracisternal (i.c.) administration of endotoxin (LPS), we found long-lasting microgliosis, memory deficits, impaired LTP, and reduced levels of the obligatory NR1 subunit of the NMDA receptor. A single administration of DCS, 1 day after i.c. LPS reduced microgliosis, reversed the cognitive deficits and restored LTP and NR1 levels. These results demonstrate that neuroinflammation alone, in the absence of trauma or ischemia, can cause persistent (>6 months) memory deficits linked to deranged NNMDA receptor function and suggest a possible role for NMDA co-agonists in reducing the cognitive sequelae of neuroinflammation.

Insights into the Pathogenesis and Treatment of Krabbe Disease

Krabbe disease (globoid cell leukodystrophy, GLD) is an inherited disease caused by a deficiency in the lysosomal enzyme galactocerebrosidase (GALC). The major galactosylated lipid degraded by GALC is galactosylceramide. However, GALC is also responsible for the degradation of galactosylsphingosine (psychosine), a highly cytotoxic glycolipid. It has been hypothesized that GALC-deficiency leads to psychosine accumulation that preferentially kills oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. Krabbe disease has traditionally been considered a white matter disease characterized by the loss and disorganization of myelin, infiltration of multinucleated monocytes/macrophages (globoid cells) and lymphocytes, and dysregulation of pro-inflammatory cytokines and chemokines. However, new studies have revealed unexpected neuronal deficiencies. Infantile Krabbe disease is believed to be the most common and aggressive form. However, juvenile and adult onset forms have been described. Children affected with infantile Krabbe disease present with motor dysfunction, cognitive decline, intractable seizures, and premature death between two to five years of age. Murine, canine, and primate models of GALC deficiency have been described and have played an important role in our understanding of this invariably fatal disease. Although there is no cure for Krabbe disease, hematopoietic stem cell transplantation can slow the progression of disease. Recent pre-clinical data indicate that simulataneously targeting multiple pathogenic mechanisms greatly increases efficacy in the murine model of Krabbe disease. A better understanding of the underlying pathogenesis will identify new therapeutic targets that may further increase efficacy.

Enhancing panic and smoking reduction treatment with d-cycloserine: Study protocol for a randomized controlled trial

There has been relatively little attention focused on treatment strategies for smokers with panic attacks despite their increased risk of relapse. Panic and Smoking Reduction Treatment (PSRT) integrates standard smoking cessation treatment with an exposure-based intervention targeting the mechanisms underlying panic-smoking relations. Building upon emerging evidence supporting the efficacy of d-cycloserine (DCS) for augmenting exposure-based therapy, we are conducting an initial test of the efficacy of DCS for enhancing PSRT outcomes. Utilizing a randomized, double-blind trial comparing PSRT+DCS to PSRT+placebo, we will obtain initial effect sizes for short-term and long-term smoking cessation outcomes and perform an initial test of putative mechanisms.

Examining the efficacy of d-cycloserine to augment therapeutic learning in depression

Despite advances in individual and combined treatments for major depression, issues with non-response and partial-response remain relatively common, motivating the search for new treatment strategies. This study aims to develop one such novel treatment. In this proof-of-concept study, we are investigating whether the treatment enhancing effects of d-cycloserine (DCS) administration can be extended outside the extinction-learning paradigms where they have been primarily examined. Using uniform delivery of cognitive behavioral therapy (CBT) content via computer-administered interventions for depression, we are assessing the value of pre-session administrations of DCS for retention of therapeutic learning. Recall of this information is evaluated in conjunction with performance on standardized tests of memory recall with both emotional and non-emotional stimuli. Specifically, in a randomized, double-blind trial we will compare the benefits of two pre-session administrations of DCS augmentation to those achieved by similar administrations of modafinil or placebo. Because modafinil is associated with a number of discriminable effects in addition to cognitive enhancement (e.g., feelings of vigor, alertness, positive mood); whereas these effects would not be expected with DCS, we will assess drug context effects in relation to memory augmentation effects.

The Therapeutic Role of d-Cycloserine in Schizophrenia

The ketamine model for schizophrenia has led to several therapeutic strategies for enhancing N-methyl d-aspartate (NMDA) receptor activity, including agonists directed at the glycine receptor site and inhibitors of glycine reuptake. Because ketamine may primarily block NMDA receptors on inhibitory interneurons, drugs that reduce glutamate release have also been investigated as a means of countering a deficit in inhibitory input. These approaches have met with some success for the treatment of negative and positive symptoms, but results have not been consistent. An emerging approach with the NMDA partial agonist, d-cycloserine (DCS), aims to enhance plasticity by intermittent treatment. Early trials have demonstrated benefit with intermittent DCS dosing for negative symptoms and memory. When combined with cognitive remediation, intermittent DCS treatment enhanced learning on a practiced auditory discrimination task and when added to cognitive behavioral therapy, DCS improved delusional severity in subjects who received DCS with the first CBT session. These studies require replication, but point toward a promising strategy for the treatment of schizophrenia and other disorders of plasticity.

A randomized, placebo-controlled trial of D-cycloserine for the enhancement of social skills training in autism spectrum disorders

BACKGROUND

Researchers have demonstrated that d-cycloserine (DCS) can enhance the effects of behavioral interventions in adults with anxiety and enhances prosocial behavior in animal models of autism spectrum disorders (ASD). This study extended upon this background by combining DCS with behavioral social skills therapy in youth with ASD to assess its impact on the core social deficits of ASD. We hypothesized that DCS used in combination with social skills training would enhance the acquisition of social skills in children with ASD.

METHODS

A 10-week, double-blind, placebo-controlled trial of DCS (50 mg) given 30 min prior to weekly group social skills training was conducted at two sites. Children with ASD were randomized to receive 10 weeks (10 doses) of DCS or placebo in a 1:1 ratio.

RESULTS

No statistically significant difference attributable to drug treatment was observed in the change scores for the primary outcome measure, the Social Responsiveness Scale (SRS), total score (p = 0.45), or on secondary outcome measures.

CONCLUSIONS

The results of this trial demonstrated no drug-related short-term improvement on the primary outcome measure, or any of the secondary outcome measures. However, an overall significant improvement in SRS total raw score was observed from baseline to end of treatment for the entire group of children with ASD. This suggests a need to further study the efficacy of the social skills training protocol. Limitations to the current study and areas for future research are discussed.

TRIAL REGISTRATION

ClinicalTrials.govNCT01086475.

Extinction learning as a moderator of d-cycloserine efficacy for enhancing exposure therapy in posttraumatic stress disorder

Augmentation of exposure therapy with d-cycloserine (DCS) has proven efficacious across anxiety disorders, although results in PTSD have been mixed. Work in animals and anxiety-disordered patients suggest that the potentiating effects of DCS are dependent on the level of extinction learning during extinction training and exposure treatment, respectively. The aim of the current study was to replicate and extend previous work by examining the association between the degree of extinction learning and DCS efficacy in our randomized clinical trial on DCS (50 mg) versus placebo enhancement of exposure therapy in a chronic mixed-trauma PTSD sample (N=67; de Kleine, Hendriks, Kusters, Broekman, & van Minnen, 2012). The decline in subjective units of distress ratings collected during and across the exposure sessions were evaluated as indices of extinction learning. First, we examined whether extinction learning during an exposure session moderated DCS effects on self-reported PTSD symptoms at the next session. Second, we examined whether averaged extinction learning over the course of treatment interacted with group assignment to predict change over time and post treatment outcome. We did not find evidence that DCS effects were moderated by the degree of extinction learning, although, extinction learning was related to outcome regardless of group assignment. In PTSD, not one extinction-learning index has been consistently linked to DCS enhanced exposure treatment outcome. More (experimental) work needs to been done to unravel the complex interplay between extinction learning and DCS enhancement, especially in PTSD patients.

Low Serum Concentrations of Moxifloxacin, Prothionamide, and Cycloserine on Sputum Conversion in Multi-Drug Resistant TB

PURPOSE

Low serum concentrations of drugs used to treat multi-drug resistant tuberculosis (MDR-TB) have occasionally been associated with treatment failure. We determined the frequencies of low serum concentrations of anti-MDR-TB drugs, and assessed the effects of these concentrations on 2-month sputum conversion.

MATERIALS AND METHODS

The serum levels of moxifloxacin (MF), prothionamide (PTH), and cycloserine (CS) were determined for 89 serum samples by high-pressure liquid chromatography-tandem mass spectrometry.

RESULTS

Low serum concentrations of MF, PTH, and CS below the minimal levels of the normal ranges were 83.3% (20/24), 59.2% (29/49), and 71.2% (47/66), respectively. There were no significant differences between the 2-month sputum conversion group (n=25) and the 2-month sputum non-conversion group (n=4) in median drug concentrations (μg/mL) of MF (1.46 vs. 1.60), PTH (0.91 vs. 0.70), and CS (14.90 vs. 14.90). However, a poor compliance rate was significantly greater in the 2-month sputum non-conversion group (75.0%, 3/4) than in the 2-month sputum conversion group (0%, 0/25) (p=0.001).

CONCLUSION

The frequency of low serum concentrations of anti-MDR-TB drugs was substantial and might not affect the 2-month sputum conversion rate. Larger prospective studies with timely sampling are needed to investigate the role of therapeutic drug monitoring in MDR-TB.

Augmentation of cognitive and behavioural therapies (CBT) with d-cycloserine for anxiety and related disorders

BACKGROUND

A significant number of patients who suffer with anxiety and related disorders (that is post-traumatic stress disorder (PTSD), social anxiety disorder (SAnD), panic disorder with or without agoraphobia (PD), specific phobia (SPh) and obsessive compulsive disorder (OCD)) fail to respond optimally to first-line treatment with medication or cognitive and behavioural therapies. The addition of d-cycloserine (DCS) to cognitive and behavioural therapies may improve treatment response by impacting the glutamatergic system. This systematic review aimed to investigate the effects of adding DCS to cognitive and behavioural therapies by synthesising data from relevant randomised controlled trials and following the guidelines recommended by Cochrane.

OBJECTIVES

To assess the effect of DCS augmentation of cognitive and behavioural therapies compared to placebo augmentation of cognitive and behavioural therapies in the treatment of anxiety and related disorders. Additionally, to assess the efficacy and tolerability of DCS across different anxiety and related disorders.

SEARCH METHODS

This review fully incorporates studies identified from a search of the Cochrane Depression, Anxiety and Neurosis Controlled Trials Register (CCDANCTR) to 12 March 2015. This register includes relevant randomised controlled trials (RCTs) from: the Cochrane Library (all years), EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date), the World Health Organization's trials portal (ICTRP) and ClinicalTrials.gov . Reference lists from previous meta-analyses and reports of RCTs were also checked. No restrictions were placed on language, setting, date or publication status.

SELECTION CRITERIA

All RCTs of DCS augmentation of cognitive and behavioural therapies versus placebo augmentation of cognitive and behavioural therapies for anxiety and related disorders were included.

DATA COLLECTION AND ANALYSIS

Two authors (RO and TA) independently assessed RCTs for eligibility and inclusion, extracted outcomes and risk of bias data and entered these into a customised extraction form. Investigators were contacted to obtain missing data. In addition, data entry and analysis were performed by two review authors (KSW and HB).

MAIN RESULTS

Twenty-one published RCTs, with 788 participants in outpatient settings, were included in the review. Sixteen studies had an age range of 18 to 75 years, while four investigated paediatric populations aged 8 to 17 years and one included children, adolescents and adults. The 21 RCTs investigated OCD (number of RCTs (N) = 6), PTSD (N = 5), SAnD (N = 5), SPh (N = 3) and PD (N = 2). Most information from the studies was rated as having either low risk or unclear risk of bias.There was no evidence of a difference between DCS augmentation of cognitive and behavioural therapies and placebo augmentation of cognitive and behavioural therapies for the treatment of anxiety and related disorders in adults at the endpoint (treatment responders, N = 9, risk ratio (RR) 1.10; 95% confidence interval (CI) 0.89 to 1.34; number of participants (n) = 449; low quality evidence) and between 1 and 12 months follow-up (N = 7, RR 1.08; 95% CI 0.90 to 1.31; n = 383). DCS augmentation of cognitive and behavioural therapies was not superior to placebo augmentation of cognitive and behavioural therapies for children and adolescents, both at the endpoint (N = 4, RR 1.01; 95% CI 0.78 to 1.31; n = 121; low quality evidence) and between 3 and 12 months follow-up (N = 3, RR 0.86; 95% CI 0.67 to 1.09; n = 91).There was no evidence of a difference in treatment acceptability for DCS augmentation of cognitive and behavioural therapies compared with placebo augmentation of cognitive and behavioural therapies in adults (N = 16, RR 0.88; 95% CI 0.61 to 1.25; n = 740), nor in children and adolescents (N = 4, RR 0.90; 95% CI 0.17 to 4.69; n = 131). These conclusions were based on moderate quality evidence for adults, and very low quality evidence for children and adolescents. Although the observed difference was small, it is noteworthy that there was a high efficacy of exposure-based therapies alone in the included trials. Due to the limited number of studies, subgroup analysis of moderating factors for clinical and methodological effect could not take place.

AUTHORS' CONCLUSIONS

This review found no evidence of a difference between DCS augmentation of cognitive and behavioural therapies and placebo augmentation of cognitive and behavioural therapies for treating anxiety and related disorders in children, adolescents and adults. These findings are based on low quality evidence from heterogenous studies with small sample sizes and incomplete data for clinical response, which precludes us from drawing conclusions on the use of DCS augmentation of cognitive and behavioural therapies at this stage. Given there is some promising preliminary data from individual studies, further research is necessary to assess DCS compared with placebo augmentation of cognitive and behavioural therapies, and determine mechanisms of action as well as magnitude of effect in anxiety and related disorders.

D-cycloserine 24 and 48 hours after asphyxial cardiac arrest has no effect on hippocampal CA1 neuropathology

Stimulation of N-methyl-D-aspartate receptors (NMDAR) contributes to regenerative neuroplasticity following the initial excitotoxic insult during cerebral ischemia. Stimulation of NMDAR with the partial NMDAR agonist D-cycloserine (DCS) improves outcome and restores hippocampal synaptic plasticity in models of closed head injury. We thus hypothesized that DCS would improve outcome following restoration of spontaneous circulation (ROSC) from cardiac arrest (CA). DCS (10 mg/kg, IP) was administered to Sprague-Dawley rats (male, 250-330 g; 63-84 days old) 24 and 48 hours after 6 or 8 minutes of asphyxial CA. Heart rate and blood pressure declined similarly in all groups. Animals showed neurological deficits after 6 and 8 minutes CA (P<0.05, Tukey) and these deficits recovered more quickly after 6 minutes than after 8 minutes of CA. CA decreased the number of healthy neurons within CA1 with no difference between 6 and 8 minutes duration of CA (180.8±27.6 (naïve, n=5) versus 46.3±33.8 (all CA groups, n=27) neurons per mm CA1). DCS had no effect on neurological deficits or CA1 hippocampal cell counts (P>0.05, Tukey).

Does D-cycloserine enhance exposure therapy for anxiety disorders in humans? A meta-analysis

The treatment of anxiety is on the edge of a new era of combinations of pharmacologic and psychosocial interventions. A new wave of translational research has focused on the use of pharmacological agents as psychotherapy adjuvants using neurobiological insights into the mechanism of the action of certain psychological treatments such as exposure therapy. Recently, d-cycloserine (DCS) an antibiotic used to treat tuberculosis has been applied to enhance exposure-based treatment for anxiety and has proved to be a promising, but as yet unproven intervention. The present study aimed to evaluate the efficacy of DCS in the enhancement of exposure therapy in anxiety disorders. A systematic review/meta-analysis was conducted. Electronic searches were conducted in the databases ISI-Web of Science, Pubmed and PsycINFO. We included only randomized, double-blind, placebo-controlled trials with humans, focusing on the role of DCS in enhancing the action of exposure therapy for anxiety disorders. We identified 328 references, 13 studies were included in our final sample: 4 on obsessive-compulsive disorder, 2 on panic disorder, 2 on social anxiety disorder, 2 on posttraumatic stress disorder, one on acrophobia, and 2 on snake phobia. The results of the present meta-analysis show that DCS enhances exposure therapy in the treatment of anxiety disorders (Cohen d =  −0.34; CI: −0.54 to −0.14), facilitating the specific process of extinction of fear. DCS seems to be effective when administered at a time close to the exposure therapy, at low doses and a limited number of times. DCS emerges as a potential new therapeutic approach for patients with refractory anxiety disorders that are unresponsive to the conventional treatments available. When administered correctly, DCS is a promising strategy for augmentation of CBT and could reduce health care costs, drop-out rates and bring faster relief to patients.

A trial of D-cycloserine to treat stereotypies in older adolescents and young adults with autism spectrum disorder

OBJECTIVES

Autism spectrum disorders (ASDs) have core impairments in social communication as well as the presence of repetitive, stereotypic behaviors and restricted interests. Older adolescents and young adults are particularly impacted by these deficits. Preclinical data implicate glutamatergic dysfunction in the pathophysiology of ASDs. D-Cycloserine (DCS), a partial glycineB agonist at the N-methyl-D-aspartic acid receptor site, has been shown to improve sociability in mouse models and a small human study. The sensitivity of the obligatory glycineB co-agonist binding site may change with daily administration of DCS as a result of agonist-induced desensitization. The efficacy of a "pulsed" once-weekly administration versus "daily" administration of DCS was compared.

METHODS

Males and females, ages 14 to 25 years, with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision diagnosis of an ASD were enrolled in a double-blind, randomized 10-week trial consisting of 8 weeks of active drug with either weekly or daily administration of 50 mg of DCS followed by a 2-week follow-up visit.

RESULTS

For the purposes of this study, no statistical or clinical differences existed between the 2 dosage groups on the Aberrant Behavior Checklist subscale 3, which measures stereotypies/repetitive movements. When combining groups, a statistically significant decrease of 37% was found from baseline to week 8 when study drug was completed using a linear mixed effects model (P = 0.003).

CONCLUSIONS

D-Cycloserine was shown to be effective in improving stereotypic symptoms in older adolescents and young adults with ASDs measured by the Aberrant Behavior Checklist subscale 3. In addition, DCS was safe and well tolerated.

Impact of DCS-facilitated cue exposure therapy on brain activation to cocaine cues in cocaine dependence

BACKGROUND

The development of addiction is marked by a pathological associative learning process that imbues incentive salience to stimuli associated with drug use. Recent efforts to treat addiction have targeted this learning process using cue exposure therapy augmented with d-cycloserine (DCS), a glutamatergic agent hypothesized to enhance extinction learning. To better understand the impact of DCS-facilitated extinction on neural reactivity to drug cues, the present study reports fMRI findings from a randomized, double-blind, placebo-controlled trial of DCS-facilitated cue exposure for cocaine dependence.

METHODS

Twenty-five participants completed two MRI sessions (before and after intervention), with a cocaine-cue reactivity fMRI task. The intervention consisted of 50mg of DCS or placebo, combined with two sessions of cocaine cue exposure and skills training.

RESULTS

Participants demonstrated cocaine cue activation in a variety of brain regions at baseline. From the pre- to post-study scan, participants experienced decreased activation to cues in a number of regions (e.g., accumbens, caudate, frontal poles). Unexpectedly, placebo participants experienced decreases in activation to cues in the left angular and middle temporal gyri and the lateral occipital cortex, while DCS participants did not.

CONCLUSIONS

Three trials of DCS-facilitated cue exposure therapy for cocaine dependence have found that DCS either increases or does not significantly impact response to cocaine cues. The present study adds to this literature by demonstrating that DCS may prevent extinction to cocaine cues in temporal and occipital brain regions. Although consistent with past research, results from the present study should be considered preliminary until replicated in larger samples.

D-cycloserine in prelimbic cortex reverses scopolamine-induced deficits in olfactory memory in rats

A significant interaction between N-methyl-D-aspartate (NMDA) and muscarinic receptors has been suggested in the modulation of learning and memory processes. The present study further investigates this issue and explores whether d-cycloserine (DCS), a partial agonist at the glycine binding site of the NMDA receptors that has been regarded as a cognitive enhancer, would reverse scopolamine (SCOP)-induced amnesia in two olfactory learning tasks when administered into the prelimbic cortex (PLC). Thus, in experiment 1, DCS (10 µg/site) was infused prior to acquisition of odor discrimination (ODT) and social transmission of food preference (STFP), which have been previously characterized as paradigms sensitive to PLC muscarinic blockade. Immediately after learning such tasks, SCOP was injected (20 µg/site) and the effects of both drugs (alone and combined) were tested in 24-h retention tests. To assess whether DCS effects may depend on the difficulty of the task, in the STFP the rats expressed their food preference either in a standard two-choice test (experiment 1) or a more challenging three-choice test (experiment 2). The results showed that bilateral intra-PLC infusions of SCOP markedly disrupted the ODT and STFP memory tests. Additionally, infusions of DCS alone into the PLC enhanced ODT but not STFP retention. However, the DCS treatment reversed SCOP-induced memory deficits in both tasks, and this effect seemed more apparent in ODT and 3-choice STFP. Such results support the interaction between the glutamatergic and the cholinergic systems in the PLC in such a way that positive modulation of the NMDA receptor/channel, through activation of the glycine binding site, may compensate dysfunction of muscarinic neurotransmission involved in stimulus-reward and relational learning tasks.

A high-throughput clinical assay for testing drug facilitation of exposure therapy

OBJECTIVE

Several studies have demonstrated that D-cycloserine (DCS) facilitates exposure therapy. We developed a standardized test of this facilitation (i.e., a clinical assay), with the goal of testing for facilitation more quickly and inexpensively than a full clinical trial.

METHOD

We developed a standardized brief exposure in which participants with social anxiety disorder gave a videotaped speech. Participants were randomized to receive a single capsule of 250 mg DCS or a matching placebo prior to preparation for the speech. Distress levels were rated during the speech and again, approximately 1 week later, during a speech in an identical situation. Our primary measure of DCS's exposure-facilitating effect was between-session habituation: whether or not the participants showed less distress during the second speech compared to the first. We also measured levels of subjective anxiety and fear of scrutiny.

RESULTS

Subjects randomized to receive DCS prior to their first speech were more likely to show between-session habituation than those who received placebo. We also found greater reduction of performance-related fear overall in the DCS group.

CONCLUSION

Our clinical assay was able to detect exposure facilitation effects rapidly and in a highly standardized way, and is estimated to take a fraction of the time and costs of a clinical trial. Given the increasing interest in using medications to enhance learning-based psychotherapy, this high-throughput clinical assay approach may be a favorable method for testing novel mechanisms of action, and clarifying optimal parameters, for therapy facilitation.

How to erase memory traces of pain and fear

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Currently emerging concepts of maladaptive pain and fear suggest that they share basic neuronal circuits and cellular mechanisms of memory formation.

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Recent studies have revealed processes of erasing memory traces of pain and fear that may be promising targets for future therapies.

Pain and fear are both aversive experiences that strongly impact on behaviour and well being. They are considered protective when they lead to meaningful, adaptive behaviour such as the avoidance of situations that are potentially dangerous to the integrity of tissue (pain) or the individual (fear). Pain and fear may, however, become maladaptive if expressed under inappropriate conditions or at excessive intensities for extended durations. Currently emerging concepts of maladaptive pain and fear suggest that basic neuronal mechanisms of memory formation are relevant for the development of pathological forms of pain and fear. Thus, the processes of erasing memory traces of pain and fear may constitute promising targets for future therapies.

Serious treatment related adverse drug reactions amongst anti-retroviral naïve MDR-TB patients

BACKGROUND

Globally treatment outcomes for multidrug-resistant Mycobacterium tuberculosis (MDR-TB) remain poor and this is compounded by high drug toxicity. Little is known about the influence of adverse drug reactions (ADRs) on treatment outcomes in South Africa.

METHODS

We evaluated the impact of severe ADRs among a prospective cohort of MDR-TB patients in South Africa (2000-2004). The HIV-infected study participants were anti-retroviral naïve.

RESULTS

Of 2,079 patients enrolled, 1,390 (66.8%) were included in this analysis based on known HIV test results (39.1% HIV-infected). At least one severe ADR was reported in 83 (6.9%) patients with ototoxicity being the most frequent ADR experienced (38.9%).

CONCLUSIONS

We found that being HIV-infected but antiretroviral naïve did not increase occurrence of SADRs in patients on second-line anti-tuberculosis drugs. Early screening and proactive management of ADRs in this patient population is essential, especially given the rollout of decentralized care and the potential for overlapping toxicity of concomitant MDR-TB and HIV treatment.

Effects of D-cycloserine on cue-induced craving and cigarette smoking among concurrent cocaine- and nicotine-dependent volunteers

Rates of cigarette smoking are 3- to 4-fold greater among those with cocaine-dependence, and compared to non-users, cocaine users are at greater risk of incurring smoking-related negative health effects and death. The current study examined D-cycloserine's (0 or 50mg once weekly) effects on 1) extinction of cue-induced craving for cigarettes, 2) cigarette smoking in conjunction with cognitive-behavioral therapy, and 3) safety and tolerability in cocaine-dependent smokers. This was a double-blind, placebo-controlled, between groups, outpatient study. Participants (N=29) were concurrent cocaine- and nicotine-dependent volunteers seeking treatment for their cigarette smoking. Study visits were 3 times per week for 4 consecutive weeks. At each visit, participants received cognitive-behavioral therapy for smoking, were exposed to smoking cues. A subset of participants (N=22) returned for 6-month follow-up visits. While craving decreased, no significant effects of D-cycloserine treatment were observed. Likewise, significant decreases in smoking were observed at study days 6 (p<0.002) and 12 (p<0.0001) relative to baseline, although no participants achieved complete abstinence. However, there was no effect of D-cycloserine on cigarette smoking during treatment or at 6-mos follow-up. The treatment was safe and tolerable, with nearly 90% of treatment sessions attended based on an intent-to-treat analysis. While no effects of D-cycloserine on craving or smoking were observed in the current study, the results do suggest that smoking treatment is well accepted and may be effective for cocaine-dependent individuals.

Augmentation of exposure therapy with post-session administration of D-cycloserine

BACKGROUND

Pre-session administration of d-cycloserine (DCS) has been found to augment exposure therapy outcomes in a variety of anxiety disorders. To be able to enhance learning only for successful exposure sessions, it would be beneficial to have the option of administering DCS after rather than before the session, a strategy encouraged by pre-clinical work. We believe the present study is the first published report on the efficacy of post-session administration of DCS in humans.

METHOD

Adults (N = 29) with a DSM-IV diagnosis of acrophobia were randomized to receive two sessions of virtual reality exposure therapy (VRE) in combination with placebo or 50 mg of DCS. Instead of administering the pill prior to each of the sessions, as has been done in extant work, we administered the pill immediately following each session. Measures of acrophobia severity were collected at baseline, at each treatment session, 1-week post-treatment, and at 1-month follow-up.

RESULTS

Mixed-effects repeated-measures ANOVAs and GLMMs revealed significant improvement in all outcome measures over time, but no between-group differences were observed. At post-treatment, 63.5% of patients in the placebo condition vs. 60.0% of those in the DCS condition were in remission. At 1-month follow up, 63.4% of those in the placebo condition vs. 66.6% of those in the DCS condition were in remission.

CONCLUSIONS

These findings do not support the application of post-session DCS administration for augmenting the efficacy of exposure-based treatments. Possible reasons for these findings are discussed.

TRIAL REGISTRY

The Trial is registered at ClinicalTrials.gov (NCT01102803).

Treatment of tuberculosis in South Kazakhstan: clinical and economical aspects

BACKGROUND AND OBJECTIVE

Since 1990, the tuberculosis incidence rate in Eastern Europe and post-Soviet republics has been increasing in many countries including Kazakhstan. This problem is particularly important in Kazakhstan regions with limited financial resources, among them - in South Kazakhstan province. The aim of this study was to investigate the main clinical and antibiotic-related economic aspects of tuberculosis treatment in South Kazakhstan province.

MATERIAL AND METHODS

In total, 502 patients participated in the study. They were hospitalized to the tuberculosis dispensary of Sayram district (South Kazakhstan province) in 2007-2013. Statistical analysis included logistic regression for better treatment outcomes and analysis of antibiotic treatment costs.

RESULTS

Two-thirds of patients had infiltrative tuberculosis (67%). Positive treatment outcomes were determined in 85% of cases. The patients were mostly treated with cycloserine, protionamide, capreomycin, and ofloxacin. The majority of antibiotic costs were related to the treatment with capreomycin. In case of the positive results of the test for Mycobacterium tuberculosis, antibiotic expenses were almost 3 times greater than in case of negative test results (P<0.001).

CONCLUSIONS

The majority of patients had extensively drug-resistant tuberculosis. The negative results of the test for Mycobacterium tuberculosis at discharge were not related to pretreatment factors. Antibiotic-related costs were significantly higher in case of the positive results of the test of Mycobacterium tuberculosis, but were not associated with gender, residence place, hospitalization recurrence, or main blood test results before treatment.