A single, subanesthetic dose of (R,S)-ketamine (ketamine) exerts rapid and robust antidepressant effects. Several groups previously reported that (2S,6S;2R,6R)-hydroxynorketamine (HNK) had ...antidepressant effects in rodents, and that (2R,6R)-HNK increased cortical electroencephalographic gamma power. This exploratory study examined the relationship between ketamine metabolites, clinical response, psychotomimetic symptoms, and gamma power changes in 34 individuals (ages 18-65) with treatment-resistant depression (TRD) who received a single ketamine infusion (0.5 mg/kg) over 40 min. Plasma concentrations of ketamine, norketamine, and HNKs were measured at 40, 80, 120, and 230 min and at 1, 2, and 3 days post-infusion. Linear mixed models evaluated ketamine metabolites as mediators of antidepressant and psychotomimetic effects and their relationship to resting-state whole-brain magnetoencephalography (MEG) gamma power 6-9 h post-infusion. Three salient findings emerged. First, ketamine concentration positively predicted distal antidepressant response at Day 11 post-infusion, and an inverse relationship was observed between (2S,6S;2R,6R)-HNK concentration and antidepressant response at 3 and 7 days post-infusion. Norketamine concentration was not associated with antidepressant response. Second, ketamine, norketamine, and (2S,6S;2R,6R)-HNK concentrations at 40 min were positively associated with contemporaneous psychotomimetic symptoms; post-hoc analysis revealed that ketamine was the predominant contributor. Third, increased (2S,6S;2R,6R)-HNK maximum observed concentration (C
) was associated with increased MEG gamma power. While contrary to preclinical observations and our a priori hypotheses, these exploratory results replicate those of a recently published study documenting a relationship between higher (2S,6S;2R,6R)-HNK concentrations and weaker antidepressant response in humans and provide further rationale for studying gamma power changes as potential biomarkers of antidepressant response.
Viloxazine extended‐release capsules (viloxazine ER; Qelbree) is a novel nonstimulant, recently approved by the US Food and Drug Administration for the treatment of ADHD in pediatrics. Here, we ...characterize the pharmacokinetics (PK) of viloxazine and its major metabolite, 5‐HVLX‐gluc, using a population PK model and evaluate the impact of 1‐4 days of missed viloxazine ER doses on viloxazine PK. Data from 4 phase 3 trials in pediatric subjects treated with viloxazine ER were used to establish the PK model. Covariate analysis was conducted on the final base model. The impact of 1‐4 days of missed doses on steady‐state viloxazine PK was evaluated using Monte Carlo simulations. A 1‐compartmental linear model with first‐order absorption and elimination of the parent drug and first‐order metabolite formation and elimination properly described the population PK of viloxazine and 5‐HVLX‐gluc. Body weight impacted the systemic exposure of viloxazine and 5‐HVLX‐gluc. Predicted PK parameters at steady state (mean ± standard deviation) in children receiving viloxazine ER were determined. Cmax was 1.60 ± 0.70 μg/mL at 100 mg, 2.83 ± 1.31 μg/mL at 200 mg, and 5.61 ± 2.48 μg/mL at 400 mg. AUC0‐t was 19.29 ± 8.88 μg·h/mL at 100 mg, 34.72 ± 16.53 μg·h/mL at 200 mg, and 68.00 ± 28.51 μg·h/mL at 400 mg. PK parameters for adolescents receiving viloxazine ER were also determined. Cmax was 2.06 ± 0.90 μg/mL at 200 mg, 4.08 ± 1.67 μg/mL at 400 mg, and 6.49 ± 2.87 μg/mL at 600 mg. AUC0‐t was 25.78 ± 11.55 μg·h/mL at 200 mg, 50.80 ± 19.76 μg·h/mL at 400 mg, and 79.97 ± 36.91 μg·h/mL at 600 mg. Simulations revealed that, regardless of the duration of the dosing interruption, viloxazine concentration returned to steady‐state levels after approximately 2 days of once‐daily dosing of viloxazine ER.
NV-5138 (S-2-amino-5,5-difluoro-4,4-dimethylpentanoic acid) is an orally bioavailable, small-molecule activator of the mechanistic target of rapamycin complex 1 (mTORC1) pathway in development for ...treatment-resistant depression. The authors established a model to describe the relationship between plasma and cerebrospinal fluid (CSF) concentrations of NV-5138 and between CSF concentrations and potential biomarkers thought to be associated with mTORC1 activity (ie, orotic acid, N-acetylmethionine, and N-formylmethionine).
Data were collected from a randomized, double-blind, placebo-controlled, tolerability, and pharmacokinetic (PK) parameter study of 5 ascending (400, 800, 1600, 2400, and 3000 mg), once-daily oral doses of NV-5138 in healthy subjects. NV-5138 plasma PK parameter samples were collected at 15 time points over 24 hours on days 1 and 7, and at pre dose on days 2–6 for all doses. NV-5138 CSF PK parameter and CSF biomarker samples were collected on days 1 and 7 at pre dose and 4, 8, and 12 hours post dose for all doses except 3000 mg. A model-based approach was used to develop and validate a model that describes the relationship between NV-5138 in CSF and biomarker concentrations.
Twenty-four of the 42 enrolled subjects had simultaneous plasma and CSF measurements of NV-5138 and CSF biomarker concentrations and were included in the PK parameter and pharmacodynamic (PD) analyses. A 2-compartment plasma and CSF PK parameter, with indirect PD effects, model was developed and validated. NV-5138 plasma concentrations were positively correlated with those in CSF, although CSF concentrations lagged slightly behind those in plasma, as indicated by a counterclockwise hysteresis effect. Similarly, the relationship between the PD measures of mTORC1 activation and NV-5138 was also characterized by counterclockwise hysteresis, when the increase in CSF biomarker concentrations lagged behind those of NV-5138, consistent with a signaling intermediary/cascade, such as mTORC1. Maximal biomarker activation was achieved at NV-5138 CSF concentrations of approximately 3 µg/mL, which were associated with daily doses of 1600 mg NV-5138. The safety profile analysis (n = 42) found that most of the reported adverse events were mild in severity, with no severe, serious, unusual, or unexpected adverse events or any dissociative effects; 2 subjects (400-mg cohort) discontinued due to adverse events that were judged to be unrelated to study medication.
The model will be used for designing future efficacy and tolerability studies. Consecutive daily doses of NV-5138 were well tolerated in this healthy volunteer study.
Ketamine has rapid-acting antidepressant effects but is associated with psychotomimetic and other adverse effects. A 7-chlorokynurenic acid is a potent and specific glycine site N-methyl-d-aspartate ...receptor antagonist but crosses the blood-brain barrier inefficiently. Its prodrug, L-4-chlorokynurenine (4-Cl-KYN), exerts acute and sustained antidepressant-like effects in rodents and has no reported psychotomimetic effects in either rodents or healthy volunteers. This study examined whether 4-Cl-KYN has rapid antidepressant effects in individuals with treatment-resistant depression.
After a 2-week drug-free period, 19 participants with treatment-resistant depression were randomized to receive daily oral doses of 4-Cl-KYN monotherapy (1080 mg/d for 7 days, then 1440 mg/d for 7 days) or placebo for 14 days in a randomized, placebo-controlled, double-blind, crossover manner. The primary outcome measure was the Hamilton Depression Rating Scale score, assessed at several time points over a 2-week period; secondary outcome measures included additional rating scale scores. Pharmacokinetic measures of 7-chlorokynurenic acid and 4-Cl-KYN and pharmacodynamic assessments were obtained longitudinally and included 1H-magnetic resonance spectroscopy brain glutamate levels, resting-state functional magnetic resonance imaging, and plasma and cerebrospinal fluid measures of kynurenine metabolites and neurotrophic factors.
Linear mixed models detected no treatment effects, as assessed by primary and secondary outcome measures. No difference was observed for any of the peripheral or central biological indices or for adverse effects at any time between groups. A 4-Cl-KYN was safe and well-tolerated, with generally minimal associated adverse events.
In this small crossover trial, 4-Cl-KYN monotherapy exerted no antidepressant effects at the doses and treatment duration studied.ClinicalTrials.gov identifier: NCT02484456.
Once-weekly isoniazid with rifapentine (HP) for 3 months is a recommended treatment for latent tuberculosis infection in persons with HIV. HP reduces exposures of certain antiretroviral medications, ...resulting in limited options for the concomitant use of these therapies. Here, we examined the pharmacokinetics (PK), safety, and tolerability of darunavir/cobicistat with HP.
This was an open-label, fixed sequence, two-period crossover study in persons without HIV. Participants received darunavir 800 mg/cobicistat 150 mg once-daily alone for 4 days, then continued darunavir/cobicistat once-daily for days 5-19 with HP coadministration on days 5, 12, and 19. Intensive PK assessments were performed on days 4, 14, and 19. PK parameters were determined using noncompartmental methods. Geometric mean ratios with 90% confidence intervals (CIs) were calculated and compared between phases using mixed-effects models.
Thirteen participants were enrolled. Two withdrew after day 4, and one withdrew after day 14. Of the 3 withdrawals, 2 were attributed to drug-related adverse events. Darunavir area under the concentration-time curve, maximum concentrations (Cmax), and concentrations at 24 hours postdose (C24h) were reduced by 71%, 41%, and 96% ∼48-72 hours after HP administration (day 14), respectively, and 36%, 17%, and 89% with simultaneous HP administration (day 19), respectively. On day 14, 45% of the predose and 73% of C24h concentrations were below the darunavir EC50 (0.055 µg/mL).
Darunavir exposures were significantly decreased with HP coadministration. Temporal relationships between HP coadministration and the extent of induction or mixed inhibition/induction of darunavir metabolism were apparent. Coadministration of darunavir/cobicistat with 3HP should be avoided.
Abstract
Although atovaquone is effective in treating and preventing Pneumocystis pneumonia (PCP), its use is limited by nonlinear absorption and adverse events. The current study was undertaken to ...examine the activity of encochleated atovaquone (eATQ), a novel lipid-crystal nanoparticle formulation, in a mouse model of PCP. eATQ 100–200 mg was superior to commercially available atovaquone at 14 days in decreasing total Pneumocystis nuclei and asci. eATQ plus anidulafungin reduced nuclei significantly better than commercial atovaquone plus anidulafungin. eATQ is a novel formulation of atovaquone that warrants further evaluation for treatment and prevention of PCP.
In a mouse model of Pneumocystis pneumonia, a novel encochleated nanoparticle formulation of atovaquone was superior to commercially available atovaquone in clearance of infection when each drug was administered alone as well as when combined with anidulafungin.
Background and Objectives
Viloxazine extended-release (viloxazine ER) capsules (Qelbree
TM
) is a novel nonstimulant recently approved as a treatment for attention-deficit/hyperactivity disorder in ...children and adolescents. Here, we determined whether the pharmacokinetics of viloxazine are impacted by consuming the capsule contents sprinkled on applesauce rather than an intact capsule, and the effect of a high-fat meal on the pharmacokinetics of viloxazine ER.
Methods
This was a randomized, open-label, crossover, three-treatment, three-period study in healthy adults using orally administered single-dose viloxazine ER 200 mg capsules. Subjects consumed: (1) an intact capsule after a 10-h fast (control condition); (2) the capsule contents sprinkled on one tablespoon of applesauce; and (3) an intact capsule with a standard high-fat meal. Blood samples were collected for 48 h post-dosing. Relative bioavailability analyses were performed to assess the impact of each test condition against the control condition (intact capsule, fasting). The absence of an impact was indicated if the 90% confidence interval (CI) for the least-squares geometric mean ratio (LSGMR) of maximal concentration (
C
max
), the area under the concentration–time curve from time 0 to the last measurable concentration time (AUC
last
), and the area under the concentration–time curve from time 0 to infinity (AUC
inf
) were within the predetermined no-difference limits of 80–125%.
Results
Out of 27 enrolled subjects, 25 were included in the pharmacokinetic analysis. The LSGMR (90% CI) for viloxazine ER sprinkled vs. intact were 90.10% (83.35–97.40) for
C
max
, 93.71% (89.09–98.57) for AUC
last
, and 95.37% (89.80–101.28) for AUC
inf
. The LSGMR (90% CI) for viloxazine ER consumed in the fed state vs. fasting state were 90.86% (84.05–98.21) for
C
max
, 89.68% (85.26–94.33) for AUC
last
, and 92.35% (86.96–98.07) for AUC
inf
. The 90% CIs of the LSGMRs were within the predetermined no-difference limits of 80–125%. Viloxazine ER was well tolerated, with most adverse events reported as mild.
Conclusions
These data suggest that viloxazine ER can be consumed sprinkled on applesauce or as intact capsules with or without meals without significantly changing its pharmacokinetics.
SPN‐812 (viloxazine extended‐release) is a novel nonstimulant recently approved as a treatment for attention‐deficit/hyperactivity disorder in children and adolescents. Given that SPN‐812 is ...metabolized by CYP2D6 and may be coadministered with CYP2D6 inhibitors, this trial investigated the pharmacokinetics and safety of SPN‐812 coadministered with the potent CYP2D6 inhibitor paroxetine. In this single‐sequence, 3‐treatment period study in healthy volunteers, subjects received a single oral dose of 700 mg SPN‐812 alone (period 1), 20 mg daily paroxetine (10 days, period 2), followed by concurrent administration of SPN‐812 and paroxetine (period 3). Blood samples were collected for 72 hours post‐SPN‐812 dosing and analyzed for viloxazine and its primary metabolite, 5‐HVLX‐gluc. Twenty‐two healthy adults were enrolled; all completed the trial. The potential for drug interaction between SPN‐812 and paroxetine was assessed using analysis of variance on the log‐transformed pharmacokinetic parameters Cmax, AUC0‐t, and AUCinf. The least‐squares geometric mean ratios for viloxazine were (reported as the ratio of combination/SPN‐812 alone) Cmax, 116.04%; 90%CI, 109.49%‐122.99%; AUC0‐t, 134.65%; 90%CI, 127.65‐142.03; and AUCinf, 134.80%; 90%CI, 127.94%‐142.03%. CYP2D6 inhibition resulted in a modest change (<35%) on viloxazine AUCs with no change in Cmax. All adverse events were mild in severity.
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