The effect of quinidine, a strong P-glycoprotein inhibitor, on the pharmacokinetics and central nervous system distribution of naloxegol.

Naloxegol is a PEGylated, oral, peripherally acting µ-opioid receptor antagonist approved in the United States for treatment of opioid-induced constipation in patients with noncancer pain. Naloxegol is metabolized by CYP3A, and its properties as a substrate for the P-glycoprotein (PGP) transporter limit its central nervous system (CNS) permeability. This double-blind, randomized, 2-part, crossover study in healthy volunteers evaluated the effect of quinidine (600 mg PO), a CYP3A/PGP transporter inhibitor, on the pharmacokinetics and CNS distribution of naloxegol (25 mg PO). In addition, the effects of quinidine on morphine (5 mg/70 kg IV)-induced miosis and exposure to naloxegol were assessed. Coadministration of quinidine and naloxegol increased naloxegol's AUC 1.4-fold and Cmax 2.5-fold but did not antagonize morphine-induced miosis, suggesting that PGP inhibition does not increase the CNS penetration of naloxegol. Naloxegol pharmacokinetics was unaltered by coadministration of morphine and either quinidine or placebo; conversely, pharmacokinetics of morphine and its metabolites (in the presence of quinidine) were unaltered by coadministration of naloxegol. Naloxegol was safe and well tolerated, alone or in combination with quinidine, morphine, or both. The observed increase in exposure to naloxegol in the presence of quinidine is primarily attributed to quinidine's properties as a weak CYP3A inhibitor.

Effects of CYP3A Modulators on the Pharmacokinetics of Naloxegol.

Naloxegol, a peripherally acting µ-opioid receptor antagonist, was recently approved in the United States for the treatment of opioid-induced constipation. This study evaluated the effects of CYP3A inhibition and induction on the pharmacokinetics, safety, and tolerability of naloxegol. Separate open-label, nonrandomized, fixed-sequence, 3-period, 3-treatment, crossover studies of naloxegol (25 mg by mouth [PO]) in the absence or presence of the inhibitors ketoconazole (400 mg PO) and diltiazem extended release (240 mg PO), or the inducer rifampin (600 mg PO) were conducted in healthy volunteers. Area under the curve (AUC∞ ) for naloxegol was increased with coadministration of either ketoconazole (12.9-fold) or diltiazem (3.4-fold) and decreased by 89% with coadministration of rifampin compared with AUC∞ for naloxegol alone. Naloxegol was generally safe and well tolerated when given alone or coadministered with the respective CYP3A modulators; 1 subject discontinued because of elevations in liver enzymes attributed to rifampin. The exposure of naloxegol was affected substantially by ketoconazole, diltiazem, and rifampin, suggesting that it is a sensitive in vivo substrate of CYP3A4.

Absorption, distribution, metabolism, and excretion of [14C]-labeled naloxegol in healthy subjects.

OBJECTIVE: To characterize the absorption, distribution, metabolism, and excretion of naloxegol, a PEGylated derivative of the µ-opioid antagonist naloxone, in healthy male subjects. MATERIALS AND METHODS: [14C]-Labeled naloxegol (27 mg, 3.43 MBq) was administered as an oral solution to 6 fasted subjects. Blood, fecal, and urine samples were collected predose and at various intervals postdose. Naloxegol and its metabolites were quantified or identified by liquid chromatography with radiometric or mass spectrometric detection. Pharmacokinetic parameters were calculated for each subject, and metabolite identification was performed by liquid chromatography with parallel radioactivity measurement and mass spectrometry. RESULTS: Naloxegol was rapidly absorbed, with a maximum plasma concentration (geometric mean) of 51 ng/mL reached before 2 hours after dosing. A second peak in the observed naloxegol and [14C] plasma concentration-time profiles was observed at ~3 hours and was likely due to enterohepatic recycling of parent naloxegol. Distribution to red blood cells was negligible. Metabolism of [14C]-naloxegol was rapid and extensive and occurred via demethylation and oxidation, dealkylation, and shortening of the polyethylene glycol chain. Mean cumulative recovery of radioactivity was 84.2% of the total dose, with ~68.9% recovered within 96 hours of dosing. Fecal excretion was the predominant route of elimination, with mean recoveries of total radioactivity in feces and urine of 67.7% and 16.0%, respectively. Unchanged naloxegol accounted for ~1/4 of the radioactivity recovered in feces. CONCLUSIONS: Naloxegol was rapidly absorbed and cleared via metabolism, with predominantly fecal excretion of parent and metabolites.

The effects of renal impairment on the pharmacokinetics, safety, and tolerability of naloxegol.

The impact of renal impairment on the pharmacokinetics of a 25-mg oral dose of naloxegol was examined in patients with renal impairment classified as moderate, severe, or end-stage renal disease (ESRD) and compared with healthy subjects (n = 8/group). Geometric mean area under the plasma concentration-time curve (AUC) was increased in patients with moderate (1.7-fold) or severe (2.2-fold) impairment, and maximum plasma concentrations (Cmax ) were elevated in patients with moderate (1.1-fold) or severe (1.8-fold) impairment. These findings were driven by higher exposures in two patients in each of the moderate and severe impairment groups; exposures in all other patients were similar to the control group. Overall exposures in ESRD patients were similar and Cmax was 29% lower versus normal subjects. Renal impairment minimally affected other plasma pharmacokinetic parameters. As renal clearance was a minor component of total clearance, exposure to naloxegol was unaffected by the degree of renal impairment, with no correlation between either AUC or Cmax and estimated glomerular filtration rate (eGFR). Hemodialysis was an ineffective means to remove naloxegol. Naloxegol was generally well tolerated in all groups. Renal impairment could adversely affect clearance by hepatic and gut metabolism, resulting in the increased exposures observed in outliers of the moderate and severe renal impairment groups.

The effects of mild or moderate hepatic impairment on the pharmacokinetics, safety, and tolerability of naloxegol.

Naloxegol is a peripherally acting µ-opioid receptor antagonist (PAMORA) in development for the treatment of opioid-induced constipation (OIC). The pharmacokinetics of a single oral 25-mg dose of naloxegol in plasma was assessed in patients with mild (Child-Pugh class A) or moderate (Child-Pugh class B) hepatic impairment and compared with healthy volunteers. Participants were matched for sex, age, and body mass index. Hepatically impaired patients exhibited a 17%-18% decrease in area under the plasma concentration versus time curve (AUC) despite similar maximum plasma concentrations (Cmax ). This was an unexpected finding given that naloxegol is primarily cleared by the hepatic route. Time to Cmax was shorter in patients with moderate impairment (0.6 hours) versus those with mild impairment (2.3 hours) or normal subjects (2.0 hours). Mean apparent terminal half-life (t½ ) was shorter in patients with mild (9.6 hours) and moderate (7.5 hours) hepatic impairment versus healthy subjects (11.3 hours). Reductions in enterohepatic recycling of naloxegol because of hepatic impairment may explain the observed decreases in AUC and t½ observed in these patients. Naloxegol was generally well tolerated, and mild or moderate hepatic impairment appeared to have minimal effect on its pharmacokinetics and safety.

Extended-release quetiapine fumarate (quetiapine XR) as adjunctive therapy in patients with generalized anxiety disorder and a history of inadequate treatment response: a randomized, double-blind study.

BACKGROUND: For many patients with generalized anxiety disorder (GAD), first-line treatment does not lead to remission. This study investigated the efficacy and tolerability of adjunctive extended-release quetiapine fumarate (quetiapine XR) in patients with GAD and an inadequate response to selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). METHODS: Patients were randomized to quetiapine XR or placebo adjunctive to SSRI/SNRIs in an 11-week study. The primary endpoint was change from randomization to week 8 in Hamilton Anxiety Rating Scale (HAM-A) total score. Secondary variables were HAM-A psychic/somatic clusters, response, and remission, and Clinical Global Impression­Severity of Illness (CGI-S) score. RESULTS: A total of 409 patients received quetiapine XR (n=209) or placebo (n=200). The week 8 mean change in HAM-A total score was not statistically significant for quetiapine XR (­10.74; P=.079) vs placebo (­9.61). Secondary variables were generally consistent with the primary analysis, except for a significant reduction in HAM-A total score (week 1) and significant improvements in HAM-A psychic cluster and CGI-S total scores (week 8). Adverse events included dry mouth, somnolence, sedation, headache, and dizziness. CONCLUSIONS: In patients with GAD and an inadequate response to SSRI/SNRIs, adjunctive quetiapine XR did not show a statistically significant effect for the primary endpoint at week 8, although some secondary endpoints were statistically significant vs placebo. Quetiapine XR was generally well tolerated.

Extended-release quetiapine fumarate (quetiapine XR) as adjunctive therapy in patients with generalized anxiety disorder and a history of inadequate treatment response: a randomized, double-blind study.

BACKGROUND: For many patients with generalized anxiety disorder (GAD), first-line treatment does not lead to remission. This study investigated the efficacy and tolerability of adjunctive extended-release quetiapine fumarate (quetiapine XR) in patients with GAD and an inadequate response to selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). METHODS: Patients were randomized to quetiapine XR or placebo adjunctive to SSRI/SNRIs in an 11-week study. The primary endpoint was change from randomization to week 8 in Hamilton Anxiety Rating Scale (HAM-A) total score. Secondary variables were HAM-A psychic/somatic clusters, response, and remission, and Clinical Global Impression­Severity of Illness (CGI-S) score. RESULTS: A total of 409 patients received quetiapine XR (n = 209) or placebo (n = 200). The week 8 mean change in HAM-A total score was not statistically significant for quetiapine XR (­10.74; P = .079) vs placebo (­9.61). Secondary variables were generally consistent with the primary analysis, except for a significant reduction in HAM-A total score (week 1) and significant improvements in HAM-A psychic cluster and CGI-S total scores (week 8). Adverse events included dry mouth, somnolence, sedation, headache, and dizziness. CONCLUSIONS: In patients with GAD and an inadequate response to SSRI/ SNRIs, adjunctive quetiapine XR did not show a statistically significant effect for the primary endpoint at week 8, although some secondary endpoints were statistically significant vs placebo. Quetiapine XR was generally well tolerated.

Double-blind, randomized study of extended release quetiapine fumarate (quetiapine XR) monotherapy in older patients with generalized anxiety disorder.

OBJECTIVE: The objective of the study was to evaluate once-daily extended release quetiapine fumarate (quetiapine XR) monotherapy in older patients with generalized anxiety disorder (GAD). METHODS: An 11-week (9-week treatment; 2-week posttreatment), randomized, double-blind, placebo-controlled study (D1448C00015) of flexibly-dosed quetiapine XR (50-300 mg/day) or placebo conducted at 47 sites (Estonia, Poland, Russia, Ukraine, and USA) between September 2006 and April 2008. Patients (≥66 years) with DSM-IV diagnosis of GAD, Hamilton Anxiety Rating Scale (HAM-A) total score of ≥20 with item 1 (anxious mood) and 2 (tension) scores of ≥2, Clinical Global Impressions-Severity of Illness (CGI-S) score of ≥4, and Montgomery Åsberg Depression Rating Scale (MADRS) total score of ≤16 were eligible for inclusion. Primary endpoint: week 9 change from randomization in HAM-A total score. RESULTS: Patients were randomized to quetiapine XR (n = 223) or placebo (n = 227). At week 9, quetiapine XR significantly reduced HAM-A total score versus placebo (least squares mean -14.97 versus -7.21; p < 0.001); symptom improvement with quetiapine XR versus placebo was significant at week 1 (p < 0.001). At week 9, quetiapine XR demonstrated significant benefits over placebo for HAM-A response and remission rates, HAM-A psychic and somatic cluster, MADRS total, CGI-S, Pittsburgh Sleep Quality Index global, pain visual analog scale, and Quality of Life, Enjoyment and Satisfaction Questionnaire short form % maximum total scores and Clinical Global Impressions-Improvement (% patients with a score of 1/2) (all p < 0.001). Adverse events (>5% in either treatment group) included somnolence, dry mouth, dizziness, headache, and nausea. CONCLUSIONS: Quetiapine XR (50-300 mg/day) monotherapy is effective in the short term in improving symptoms of anxiety in older patients with GAD, with symptom improvement seen as early as week 1. Tolerability findings were generally consistent with the known profile of quetiapine.

Efficacy and tolerability of extended release quetiapine fumarate monotherapy in the acute treatment of generalized anxiety disorder: a randomized, placebo controlled and active-controlled study.

The main objective of this study was to evaluate efficacy and tolerability of once-daily extended release quetiapine fumarate (quetiapine XR) monotherapy in generalized anxiety disorder (GAD). This was a 8 week randomized, 2-week follow-up, double-blind, placebo-controlled, and active-controlled study. Patients were randomized to quetiapine XR 150 (n=219) or 300 mg/day (n=207); escitalopram, 10 mg/day (n=213); or placebo (n=215). The primary endpoint was the change from randomization at week 8 in Hamilton Anxiety Rating (HAM-A) total score. Week 8 mean HAM-A total score was significantly reduced from randomization with quetiapine XR 150 mg/day (-13.9, P<0.001), 300 mg/day (-12.3, P<0.05) and escitalopram (-12.3, P<0.05) versus placebo (-10.7); significant improvements with quetiapine XR (150 and 300 mg/day) versus placebo (P<0.001) were also shown at day 4. At week 8, significant improvements versus placebo were observed in HAM-A psychic [quetiapine XR (both doses) and escitalopram] and somatic (quetiapine XR 150 mg/day and escitalopram) cluster scores and HAM-A response and remission rates (quetiapine XR 150 mg/day). Most common adverse events were dry mouth, somnolence and sedation (quetiapine XR), headache, and nausea (escitalopram). In patients with GAD, quetiapine XR (150 and 300 mg/day) demonstrated significant efficacy at week 8 with symptom improvement as early as day 4. We concluded that quetiapine XR safety and tolerability results were consistent with the known profile of quetiapine.

Extended Release Quetiapine Fumarate (Quetiapine XR) as Adjunct Therapy in Patients with Generalized Anxiety Disorder and a History of Inadequate Treatment Response: A Randomized, Double-Blind Study.

OBJECTIVE: To evaluate the efficacy and tolerability of adjunct extended release quetiapine fumarate (quetiapine XR) in patients with generalized anxiety disorder (GAD) and inadequate response to selective serotonin reuptake inhibitors/ serotonin norepinephrine reuptake inhibitors (SSRI/SNRIs). METHODS: 11-week (1-week single-blind placebo run-in; 8-week randomized treatment; 2-week post-treatment period), double-blind, placebo-controlled study. Patients were randomized to quetiapine XR or placebo adjunct to SSRI/SNRI. 50 mg initial dose; 150 mg/day, Day 3; 300 mg/day, Weeks × and 4 if indicated (Clinical Global Impressions-Severity of Illness [CGI-S] ≥ 4; 150 mg/day tolerated). Primary endpoint: change from randomization to Week 8 in HAM-A total score. Secondary variables: Hamilton Rating Scale for Anxiety (HAM-A) psychic/somatic clusters, response and remission; and CGI-S. RESULTS: 409 patients were randomized to quetiapine XR (n = 209) or placebo (n = 200); 41% and 55% of patients, respectively, had dose increases (300 mg/day). Week 8 mean change in HAM-A total score was not statistically significant for quetiapine XR (-10.74; p = 0.079) versus placebo (-9.61). Secondary variables were generally consistent with the primary analysis, except a significant reduction in HAM-A total score at Week 1 (-6.45, quetiapine XR versus -4.47, placebo; p < 0.001); significant improvements in HAM-A psychic cluster (p < 0.05) and CGI-S total (p < 0.05) scores at Week 8. Adverse events (.10% either group) were dry mouth, somnolence, sedation, headache, and dizziness. CONCLUSIONS: In patients with GAD and inadequate response to SSRI/SNRI, adjunct quetiapine XR did not show a statistically significant effect for the primary endpoint at Week 8, although some secondary endpoints were statistically significant versus placebo. Quetiapine XR was generally well tolerated.