Absorption
Following oral administration, MOVANTIK is absorbed with peak concentrations (Cmax) achieved at less than 2 hours. In a majority of subjects, a secondary plasma concentration peak of naloxegol was observed approximately 0.4 to 3 hours after the first peak. Across the range of doses evaluated, peak plasma concentration and area under the plasma concentration-time curve (AUC) increased in a dose-proportional or almost dose-proportional manner. Accumulation was minimal following multiple daily doses of naloxegol.
MOVANTIK as a crushed tablet mixed in water, given orally or administered through a nasogastric tube into the stomach, provides systemic naloxegol concentrations that are comparable to the whole tablet, with a median tmax of 0.75 and 1.5 hours (range 0.25 to 5 hours) for the crushed tablet given orally and the crushed tablet given via nasogastric (NG) tube, respectively [see Dosage and Administration (2.2)].
Food Effects
A high-fat meal increased the extent and rate of naloxegol absorption. The Cmax and AUC were increased by approximately 30% and 45%, respectively. In clinical trials, naloxegol was dosed on an empty stomach approximately 1 hour prior to the first meal in the morning.
Distribution
The mean apparent volume of distribution during the terminal phase (Vz/F) in healthy volunteers ranged from 968 L to 2140 L across dosing groups and studies. Plasma protein binding of naloxegol in humans was low (~4.2%).
Metabolism
Naloxegol is metabolized primarily by the CYP3A enzyme system. In a mass balance study in humans, a total of 6 metabolites were identified in plasma, urine, and feces. These metabolites were formed via N-dealkylation, O-demethylation, oxidation, and partial loss of the PEG chain. Human metabolism data suggests absence of major metabolites. The activity of the metabolites at the opioid receptor has not been determined.
Excretion
Following oral administration of radio-labeled naloxegol, 68% and 16% of total administered dose were recovered in the feces and urine, respectively. Parent naloxegol excreted in the urine accounted for less than 6% of the total administered dose. Approximately 16% of radioactivity in feces was noted to be unchanged naloxegol, while the remaining was attributed to metabolites. Thus, renal excretion is a minor clearance pathway for naloxegol. In a clinical pharmacology study, the half-life of naloxegol at therapeutic doses ranged from 6 to 11 hours.
Specific Populations
Renal Impairment:
The effect of renal impairment on the pharmacokinetics of a 25 mg single oral dose of MOVANTIK was studied in subjects with renal impairment (RI) classified as moderate (n=8), severe (n=4), or end-stage renal disease (ESRD) not yet on dialysis (n=4), and compared with healthy subjects (n=6). Most renal impairment (RI) subjects (6 out of 8 with moderate RI, 3 out of 4 with severe RI, and 3 out of 4 with ESRD) had plasma naloxegol pharmacokinetics comparable to those in healthy subjects. The remaining individuals with renal impairment demonstrated higher naloxegol exposures (up to 10-fold) compared to the control group. The reason for these high exposures is unknown.
This study also included 8 ESRD patients on hemodialysis. Plasma concentrations of naloxegol in these subjects were similar to healthy volunteers with normal renal function, when MOVANTIK was administered either pre- or post-hemodialysis [see Dosage and Administration (2.3), Use in Specific Populations (8.6), and Overdosage (10)].
Hepatic Impairment:
Slight decreases in AUC of naloxegol were observed in subjects with mild and moderate hepatic impairment (Child-Pugh Classes A and B; n=8 per group) compared to subjects with normal hepatic function (n=8), following administration of a single 25 mg oral dose of MOVANTIK. The effect of severe hepatic impairment (Child-Pugh Class C) on the pharmacokinetics of naloxegol was not evaluated [see Use in Specific Populations (8.7)].
Age:
The mean Cmax,ss and AUCτ,ss values seen in elderly healthy Japanese subjects (n=6) were approximately 45% and 54% greater than those obtained in young healthy subjects (n=6) following multiple daily doses of naloxegol (25 mg).
Gender:
There is no gender effect on the pharmacokinetics of naloxegol.
Race:
When compared to Caucasian subjects, naloxegol AUC was approximately 20% lower in Blacks and Cmax was approximately 10% lower and 30% higher in Blacks and Asians, respectively.
Drug Interaction Studies
Effect of MOVANTIK on Other Drugs
In in vitro studies at clinically relevant concentrations, naloxegol did not show a significant inhibitory effect on the activity of CYP1A2, CYP2C8, CYP2C9, CYP2D6, CYP3A4 or CYP2C19, nor a significant induction effect on the activity of CYP1A2, CYP2B6, or CYP3A4. Therefore, MOVANTIK is not expected to alter the metabolic clearance of co-administered drugs that are metabolized by these enzymes. Naloxegol is not a significant inhibitor of P-gp, BCRP, OAT1, OAT3, OCT2, OATP1B1, and OATP1B3.
In healthy subjects receiving morphine 5 mg/70 kg intravenously, single doses of MOVANTIK ranging from 8 mg to 1000 mg were given concomitantly with 5 to 6 subjects per dose cohort. With increasing MOVANTIK dose, there was no increasing or decreasing trend in morphine exposure compared to morphine administered alone. An analysis of the pooled data indicated that MOVANTIK had no meaningful impact on the systemic exposure of morphine and its major circulating metabolites.
Effect of Other Drugs on MOVANTIK
Naloxegol is metabolized mainly by CYP3A enzymes and is a substrate of P-gp transporter. The effects of co-administered drugs on the pharmacokinetics of naloxegol are summarized in Figure 1 [see Drug Interactions (7.1)].
The effects of once daily oral dosing of 400 mg ketoconazole, once daily oral dosing of 600 mg rifampicin and once daily oral dosing of 240 mg diltiazem (as an extended release formulation) on the pharmacokinetics of 25 mg MOVANTIK were studied following multiple dosing and at steady state exposure of the perpetrator drugs. The effects of 600 mg oral dosing of quinidine and intravenous morphine (5 mg/70 kg) on the pharmacokinetics of 25 mg MOVANTIK were studied following single dosing of the perpetrator drugs.
Figure 1: Effect of Co-administered Drugs on the Pharmacokinetics of Naloxegol
*Quinidine due to its effect on P-gp transporter increased naloxegol Cmax by 2.5-fold; the AUC increased by 1.4-fold; no dosage adjustment is necessary.
No drug interaction studies have been conducted for MOVANTIK with drugs that alter gastric pH (e.g., antacids, proton-pump inhibitors).
Simulations using physiologically based pharmacokinetic modeling, suggested that naloxegol exposures after co-administration of a single oral 25 mg dose of MOVANTIK with a moderate CYP3A inducer efavirenz (400 mg once a day) are similar to those after 12.5 mg MOVANTIK alone.