Population Pharmacokinetics and Exposure-Response Relationships of Naldemedine

Impacts of genetic polymorphisms and cancer cachexia on naldemedine pharmacokinetics and bowel movements in patients receiving opioid analgesics

BACKGROUND/OBJECTIVES

Clinical responses to naldemedine vary between individuals with advanced cancer. This is a prospective, single-center, observational study aimed to evaluate the influence of genetic polymorphisms and cachexia status on plasma naldemedine and clinical responses.

METHODS

Forty-eight patients being treated with naldemedine for opioid-induced constipation under treatment of cancer pain were enrolled. Plasma naldemedine concentrations were determined on the fourth day or later after administration of naldemedine, and the associations with genotypes, cachexia status, and clinical responses were assessed.

RESULTS

Cancer patients exhibited a large variation in the plasma naldemedine concentrations, and it was correlated with serum total protein level. Patients who were homozygous CYP3A5*3 had a higher plasma concentration of naldemedine than those with the *1 allele. ABCB1 genotypes tested in this study were not associated with plasma naldemedine. A negative correlation was observed between the plasma naldemedine concentration and 4β-hydroxycholesterol level. The plasma naldemedine concentration was lower in patients with refractory cachexia than in those with precachexia and cachexia. While serum levels of interleukin-6 (IL-6) and acute-phase proteins were higher in patients with refractory cachexia, they were not associated with plasma naldemedine. A higher plasma concentration of naldemedine, CYP3A5*3/*3, and an earlier naldemedine administration after starting opioid analgesics were related to improvement of bowel movements.

CONCLUSION

Plasma naldemedine increased under deficient activity of CYP3A5 in cancer patients. Cachectic patients with a higher serum IL-6 had a lower plasma naldemedine. Plasma naldemedine, related to CYP3A5 genotype, and the initiation timing of naldemedine were associated with improved bowel movements.

Efficacy and safety of naldemedine for opioid-induced constipation in older patients with cancer: a retrospective study

BACKGROUND

Opioids are pain relievers that are often associated with opioid-induced constipation (OIC) that worsens with age. We performed a multicenter, retrospective analysis on the efficacy and safety of naldemedine, an opioid receptor antagonist, in treating OIC in patients with cancer (age >75 years).

METHODS

The electronic medical records of cancer patients who received naldemedine at 10 Japanese institutions between 7 June 2017 and August 31, 2019, were retrieved. Patients aged ≥75 years who were treated with naldemedine for the first time and hospitalized for at least 7 days before and after initiating naldemedine therapy were included in this analysis.

RESULTS

Sixty patients were observed for at least 7 days before and after starting naldemedine. The response rate was 68.3%, and the frequency of bowel movements increased significantly after naldemedine administration in the overall population ( P  < 0.0001) and among those who defecated <3 times/week before naldemedine administration ( P  < 0.0001). Diarrhea was the most frequent adverse event in all grades, observed in 45% of patients, of which 92.6% were Grade 1 or 2. Grade 4 or higher adverse events, including death, were not observed.

CONCLUSION

Naldemedine exhibits significant efficacy and safety in OIC treatment in older patients with cancer.

Efficacy and Safety of Naldemedine Administration for Opioid-Induced Constipation in Cancer Patients with Poor Performance Status

Background: Constipation is a concern among patients with Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 3 and 4. Objectives: To assess naldemedine's efficacy and safety in cancer patients on opioids with poor PS. Design: Multicenter, retrospective study. Setting/Subjects: Japanese cancer patients with ECOG performance status 3 or 4 who received naldemedine. Measurements: Frequency of defecations before/after naldemedine use. Responders were patients whose defecation frequency increased to ≥3 times/week, from baseline ≥1 defecations/week over seven days after naldemedine administration. Results: Seventy-one patients were analyzed; 66.1% were responders (95% confidence interval: 54.5%-76.1%). Defecation frequency increased significantly after naldemedine in the overall population (6 vs. 2, p < 0.0001) and among those who defecated <3 times/week before naldemedine (4.5 vs. 1, p < 0.0001). Diarrhea (38.0%) of all grades was the most common adverse event; 23 (85.2%) events were classified as Grade 1 or 2. Conclusion: Naldemedine is effective and safe among cancer patients with poor PS.

A Retrospective Study of the Efficacy and Safety of Naldemedine for Treatment of Opioid-Induced Constipation in Patients with Hepatobiliary Pancreatic Cancer

Background and Objectives: Opioid analgesics, which are used for cancer-related pain management, cause opioid-induced constipation (OIC). Naldemedine, a peripheral opioid receptor antagonist, is an OIC-modifying agent, but no focused efficacy and safety analysis has been conducted for its use in hepatobiliary pancreatic cancers. We performed a multi-institutional study on the efficacy and safety of naldemedine in patients with hepatobiliary pancreatic cancer using opioids in clinical practice. Materials and Methods: We retrospectively evaluated patients with hepatobiliary pancreatic cancer (including liver, biliary tract, and pancreatic cancers) treated with opioids and naldemedine during hospitalization at ten institutions in Japan from June 2017 to August 2019. We assessed the frequency of bowel movements before and after the initiation of naldemedine therapy. Responders were defined as patients who defecated ≥3 times/week, with an increase from a baseline of ≥1 defecations/week over seven days after the initiation of naldemedine administration. Results: Thirty-four patients were observed for one week before and one week after starting naldemedine. The frequency of bowel movements increased by one over the baseline frequency or to at least thrice per week in 21 patients. The response rate was 61.7% (95% confidence interval: 45.4–78.0%). The median number of weekly bowel movements before and after naldemedine treatment was 2 (range: 0–9) and 6 (range: 1–17), respectively, in the overall population (n = 34); the increase in the number of bowel movements following naldemedine administration was statistically significant (Wilcoxon signed-rank test, p < 0.0001). Diarrhea was the predominant gastrointestinal symptom, and 10 (29.4%) patients experienced grade 1, grade 2, or grade 3 adverse events. The only other adverse event included fatigue in one patient; grade 2–4 adverse events were absent. Conclusions: Naldemedine is effective, and its use may be safe in clinical practice for patients with hepatobiliary pancreatic cancer receiving opioid analgesics.

A retrospective study of the efficacy and safety of naldemedine for opioid-induced constipation in thoracic cancer patients

Background

We conducted a multicenter, retrospective study on the efficacy and safety of naldemedine in thoracic cancer patients using opioids in clinical practice.

Methods

We retrospectively evaluated thoracic cancer patients treated with naldemedine at 10 institutions in Japan. Clinical data of patients administered naldemedine between June 2017 and August 2019 were extracted from electronic medical records. Inclusion criteria were as follows: (i) patients hospitalized for at least seven days before and after naldemedine administration, and (ii) those whose frequency of defecation was entered in the medical records.

Results

Forty patients were analyzed, and defecation frequency was observed for at least seven days before and after naldemedine administration. The response rate was 65.0% (95% CI: 50.2%–79.7%). The number of defecations increased significantly after naldemedine administration in the overall population, as well as among only those who defecated <3 times/week before naldemedine administration, and those that were administered ≥30 mg/day of morphine equivalent. Diarrhea was the most common adverse event in all grades, occurring in 11 patients (27.5%), of which 9 (81.8%) were grade 1 or 2. None of the patients experienced grade 4 or higher adverse events.

Conclusion

The efficacy and safety of naldemedine for thoracic cancer patients in clinical practice were comparable with those of prospective studies, which suggest that naldemedine may be effective and feasible for most thoracic cancer patients.

Efficacy and Safety of Naldemedine for Patients with Cancer with Opioid-Induced Constipation in Clinical Practice: A Real-World Retrospective Study

The efficacy and safety of naldemedine for opioid-induced constipation in patients with cancer has not been investigated in clinical practice. We conducted a multicenter, retrospective study to assess the effects of naldemedine among 10 Japanese institutions between June 2017 and August 2019. We evaluated the number of defecations 7 days before and after naldemedine administration. A total of 149 patients (89 male) with a median age of 72 years (range, 38−96) were included. The performance status was 0−1, 2, and ≥3 in 40, 38, and 71 patients, respectively. The median opioid dose in oral morphine equivalents was 30 mg/day (range: 7.5−800 mg). We observed 98 responders and 51 non-responders. The median number of defecations increased significantly in the 7 days following naldemedine administration from three to six (p < 0.0001). Multivariate analysis revealed that an opioid dose <30 mg/day [odds ratio, 2.08; 95% confidence interval, 1.01−4.32; p = 0.042] was significantly correlated with the effect of naldemedine. Diarrhea was the most common adverse event (38.2%) among all grades. The efficacy and safety of naldemedine in clinical practice are comparable to those of prospective studies, suggesting that it is effective in most patients.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Naldemedine: A New Option for OIBD

Opioid-induced bowel dysfunction (OIBD) is a common complication in long-term opioid users and abusers. It is a burdensome condition, which significantly limits quality of life and is associated with increasing health costs. OIBD affects up to 60% of patients with chronic non-cancer pain and over 80% of patients suffering from cancer pain and is one of the conditions of the most common symptoms associated with opioid maintenance. Given the continued use of opioids for chronic pain management in appropriate patients, OIBD is likely to persist in clinical practice in the coming years. We will herein review its underlying pathophysiological mechanisms and the available treatments. In the last years, pharmaceutical research has focused on the opportunity of targeting peripheral mu-opioid receptors without affecting their analgesic activity in the central nervous system, and several peripherally acting mu-opioid receptors antagonists (PAMORAs) drugs have been approved. We will mainly focus on naldemedine, discussing its pharmacological properties, its clinical efficacy and side effects. Head-to-head comparisons between naldemedine and the other PAMORAs are not available yet, but some considerations will be discussed based on the pharmacological and clinical data. As a whole, the available data suggest that naldemedine is a valid treatment option for OIBD, as it is a well-tolerated drug that alleviates constipation without affecting analgesia or causing symptoms of opioid withdrawal.

Clinical Drug-Drug Interaction Studies to Evaluate the Effects of a P-Glycoprotein Inhibitor, CYP3A Inhibitors, and a CYP3A Inducer on the Pharmacokinetics of Naldemedine in Healthy Subjects

Background

Naldemedine is a peripherally acting μ-opioid receptor antagonist that is indicated to treat opioid-induced constipation.

Objectives

To assess the potential for drug-drug interactions between a single oral dose of naldemedine and the oral P-glycoprotein inhibitor cyclosporine, cytochrome P450 (CYP) 3A inhibitors itraconazole and fluconazole, and CYP3A inducer rifampin.

Methods

Three Phase 1, open-label studies were conducted in healthy subjects. In the P-glycoprotein inhibitor study, subjects received naldemedine 0.4 mg alone or coadministered with cyclosporine 600 mg. In the CYP3A inhibitors study, subjects in separate cohorts received naldemedine 0.2 mg alone or with itraconazole or fluconazole. In the CYP3A inducer study, subjects received naldemedine 0.2 mg alone or with rifampin 600 mg. Geometric mean ratios and 90 % confidence intervals were used to evaluate the effects of coadministered drugs on naldemedine maximum plasma concentration (C_max) and the area under the concentration-time curve (AUC). Safety assessments included occurrence of adverse events (AEs), laboratory parameters, vital signs, and electrocardiography results.

Results

A total of 56 subjects were enrolled (n = 14 in each cohort). Cyclosporine increased naldemedine AUC_0–inf 1.78-fold and C_max 1.45-fold. Itraconazole and fluconazole increased naldemedine AUC_0–inf 2.91-fold and 1.90-fold, and C_max 1.12-fold and 1.38-fold, respectively. Rifampin decreased naldemedine AUC_0–inf by 83% and C_max by 38%. Across studies, AEs were generally mild. Laboratory, vital sign, or electrocardiogram assessments produced no clinically significant findings.

Conclusions

Coadministration of naldemedine with a P-glycoprotein inhibitor or a strong/moderate CYP3A inhibitor increases naldemedine exposure; coadministration with a strong CYP3A inducer decreases its exposure. Coadministration of naldemedine with cyclosporine, itraconazole, fluconazole, or rifampin was generally safe and well tolerated.

Naldemedine is a targeted medication approved in the USA, Europe, and Japan for the treatment of opioid-induced constipation. Symptoms of constipation may include passing fewer stools than usual, having lumpy or hard stools, and/or straining to have bowel movements. In some cases, these symptoms are side effects of regular opioid use, which is often medically necessary for the management of moderate-to-severe pain. For naldemedine to be prescribed safely, doctors must know what other medications a patient is taking and how these medications may affect one another. This is commonly known as drug-drug interactions. Some drug-drug interactions may decrease how well a medication works, while other drug-drug interactions may increase the side effects experienced by a patient. In this paper, researchers report the results of three Phase 1 studies in healthy subjects examining how naldemedine interacts with other drugs. The drugs chosen for investigation are commonly evaluated in DDI studies and may affect the transport or metabolic pathway of naldemedine, including the P-glycoprotein inhibitor cyclosporine, the CYP3A inhibitors itraconazole and fluconazole, and the CYP3A inducer rifampin. These studies demonstrate that co-administration of naldemedine with each of these drugs impacted the pharmacokinetics of naldemedine. Cyclosporine, itraconazole, or fluconazole all increased naldemedine exposure, while rifampin decreased naldemedine exposure. For all drug combinations, observed side effects were generally mild and well tolerated. Additional testing, including vital signs and heart monitoring, did not reveal any other safety concerns. In conclusion, these findings support the cautious use of naldemedine in combination with cyclosporine, itraconazole or fluconazole. Concomitant use with rifampin should be avoided.

The Influence of Renal or Hepatic Impairment on the Pharmacokinetics, Safety, and Tolerability of Naldemedine

Naldemedine is a peripherally acting μ‐opioid‐receptor antagonist for the treatment of opioid‐induced constipation. Two phase 1 single‐dose studies investigated the pharmacokinetics and safety of a 0.2‐mg oral dose of naldemedine in subjects with renal impairment (mild, n = 9; moderate, n = 9; severe, n = 6; and end‐stage renal disease, n = 8) or hepatic impairment (mild or moderate, n = 8 each) and demographically matched healthy subjects with normal renal and hepatic function (n = 8, both studies). Pharmacokinetic assessments indicate that dose adjustments for naldemedine are not necessary for subjects with any degree of renal impairment or for subjects with mild or moderate hepatic impairment. In subjects with renal impairment compared with healthy subjects with normal renal function, the geometric mean ratios of naldemedine area under the concentration‐time curve (AUC_0‐inf) ranged from 82.8% (90%CI 69.5% to 98.6%) to 137.8% (90%CI 114.0% to 166.5%). Renal clearance decreased with reduced renal function (normal function 1.3 L/h; mild impairment 1.1 L/h; moderate impairment 1.0 L/h; severe impairment 0.5 L/h), and only 2.7% of naldemedine was removed by hemodialysis. In subjects with hepatic impairment compared with healthy subjects with normal hepatic function, the geometric mean ratio of AUC_0‐inf ranged from 82.8% (90%CI 65.7% to 104.5%) to 105.2% (90%CI 83.4% to 132.6%). Naldemedine was well tolerated in both healthy subjects and subjects with renal or hepatic impairment, and reported adverse events were generally consistent with the known safety profile.