Efficacy and safety of naloxegol in patients with opioid-induced constipation and laxative-inadequate response

Patient-Reported Outcomes in Disorders of Gut-Brain Interaction

Disorders of gut-brain interaction are characterized by chronic gastrointestinal symptoms in the absence of abnormal endoscopic or radiologic findings or objective biomarkers that can be identified during routine clinical evaluation. The assessment of the symptom pattern and severity, therefore, is the key modality to evaluate the presence, impact, and evolution of these conditions, for both clinical and regulatory purposes. Patient-reported outcomes are structured symptom assessment questionnaires designed to evaluate symptom patterns, quantify severity of symptoms, and evaluate response to treatment at follow-up. This review provides an overview of currently available patient-reported outcomes for evaluating the main disorders of gut-brain interaction, specifically, functional dyspepsia; irritable bowel syndrome; and chronic constipation. It summarizes their content, level of validation for clinical practice and for research, and the regulatory approach to these conditions. Expected future developments and need for further research on patient-reported outcomes for these and other disorders of gut-brain interaction are highlighted.

One-year efficacy and safety of naloxegol on symptoms and quality of life related to opioid-induced constipation in patients with cancer: KYONAL study

OBJECTIVES

Naloxegol is a peripherally acting µ-opioid receptor antagonist (PAMORA) for treatment of opioid-induced constipation (OIC). The main objective was to analyse the long-term efficacy, quality of life (QOL) and safety of naloxegol in patients with cancer in a real-world study.

METHODS

This one-year prospective study included patients older than 18 years, with active oncological disease who were under treatment with opioids for pain control and Karnofsky≥50 and OIC with inadequate response to treatment with laxative (s). All the patients received treatment with naloxegol according to clinical criteria. The main efficacy objectives were measured by the patient assessment of constipation QOL questionnaire (PAC-QOL), the PAC symptoms (PAC-SYM), the response rate at day 15, and months 1-3-6-12, and global QOL (EuroQoL-5D-5L).

RESULTS

A total of 126 patients (58.7% males) with a mean age of 61.5 years (95% CI 59.4 to 63.7) were included. PAC-SYM and PAC-QOL total score and all their dimensions improved from baseline (p<0.0001). At 12 months, 77.8% of the patients were responders to naloxegol treatment. Global QOL was conserved from baseline. A total of 28 adverse reactions, mainly gastrointestinal were observed in 15.1% of the patients (19/126), being 75% (21) mild, 17.9% (5) moderate and 7.1% (2) severe. Most adverse reactions (67.9%) appeared the first 15 days of treatment.

CONCLUSION

The results of this first long-term and real-world-data study in patients with cancer, showed the sustained efficacy and safety of naloxegol for the treatment of OIC in this group of patients.

Versatile Tissue-Injectable Hydrogels with Extended Hydrolytic Release of Bioactive Protein Therapeutics

Hydrogels generally have broad utilization in healthcare due to their tunable structures, high water content, and inherent biocompatibility. FDA-approved applications of hydrogels include spinal cord regeneration, skin fillers, and local therapeutic delivery. Drawbacks exist in the clinical hydrogel space, largely pertaining to inconsistent therapeutic exposure, short-lived release windows, and difficulties inserting the polymer into tissue. In this study, we engineered injectable, biocompatible hydrogels that function as a local protein therapeutic depot with a high degree of user-customizability. We showcase a PEG-based hydrogel functionalized with bioorthogonal strain-promoted azide-alkyne cycloaddition (SPAAC) handles for its polymerization and functionalization with a variety of payloads. Small-molecule and protein cargos, including chemokines and antibodies, were site-specifically modified with hydrolysable "azidoesters" of varying hydrophobicity via direct chemical conjugation or sortase-mediated transpeptidation. These hydrolysable esters afforded extended release of payloads linked to our hydrogels beyond diffusion; with timescales spanning days to months dependent on ester hydrophobicity. Injected hydrogels polymerize in situ and remain in tissue over extended periods of time. Hydrogel-delivered protein payloads elicit biological activity after being modified with SPAAC-compatible linkers, as demonstrated by the successful recruitment of murine T-cells to a mouse melanoma model by hydrolytically released murine CXCL10. These results highlight a highly versatile, customizable hydrogel-based delivery system for local delivery of protein therapeutics with payload release profiles appropriate for a variety of clinical needs.

Efficacy and Safety of Naloxegol in Patients with Chronic Non-Cancer Pain Who Experience Opioid-Induced Constipation: A Pooled Analysis of Two Global, Randomized Controlled Studies

Objective

This study evaluates the onset, magnitude, and consistency of improvement of opioid-induced constipation (OIC) symptoms with naloxegol treatment.

Methods

This was a pooled analysis of two Phase 3, double-blind, randomized, placebo-controlled studies (KODIAC-04/05, NCT01309841/NCT01323790) in patients with chronic non-cancer pain and OIC treated with naloxegol 25mg or 12.5mg daily. This analysis assessed improvements in response rates, frequency of spontaneous bowel movement (SBM) and complete SBMs (CSBM), OIC constipation symptoms (straining, stool consistency), time to first post-dose SBM and CSBM, and onset of adverse events over the 12-week period.

Subjects

The population of 1337 subjects had a mean age of 52 years and mean duration of opioid use of 3.6 years at baseline. Mean SBM frequency was 1.4/week.

Results

Naloxegol 25mg and 12.5mg demonstrated significantly higher response rates vs placebo (PBO) [41.9% (P < 0.001), 37.8% (P = 0.008), 29.4% respectively]. Rapid (within 1 week) and sustained (over 12 weeks) symptom improvement was significantly greater for naloxegol vs PBO (P < 0.05). Both doses showed statistically significant and clinically meaningful improvements in straining, stool consistency, number of SBMs and CSBMs/wk. Significantly shorter times to first post-dose SBM and CSBM were observed with naloxegol vs PBO (SBM HR: 25mg = 1.90, 12.5mg= 1.60; CSBM HR: 25mg = 1.42, 12.5mg = 1.36; P < 0.001 for each regimen). Adverse events occurred more frequently in the naloxegol 25mg group and were most frequently reported during the first week.

Conclusion

In patients with chronic non-cancer pain, naloxegol 25mg and 12.5mg demonstrated significantly higher response rates and rapid and sustained improvements in OIC symptoms compared with PBO.

Establishing Minimal Clinically Important Differences in Quality of Life Measures in Opioid-Induced Constipation

BACKGROUND & AIMS

Opioids have a role in chronic pain management. However, opioid-induced constipation may cause patients to skip or reduce opioid doses, leading to inadequate pain relief and negatively impacting quality of life. We sought to establish a minimal clinically important difference to understand whether changes in quality of life scores are of value to patients.

METHODS

Integrated data from the double-blind, controlled, phase 3 COMPOSE-1 and COMPOSE-2 trials of naldemedine in chronic noncancer pain and opioid-induced constipation were used to determine minimal clinically important differences using Patient Assessment of Constipation Symptoms (PAC-SYM) and Patient Assessment of Constipation Quality of Life (PAC-QOL) questionnaires. Patients completed the questionnaires (5-point Likert scale; predose, Weeks 2, 4, and 12), kept a daily log of Bowel Movement and Constipation Assessment, and rated satisfaction at end of study. Minimal clinically important differences were computed using an anchor-based method with 6 anchors: 5 from the Bowel Movement and Constipation Assessment and 1 from patient satisfaction. Threshold values for each anchor were set to define responders versus nonresponders based on score definitions. Clinically meaningful cutoff values for changes in PAC-SYM and PAC-QOL scores were determined using receiver operating characteristic curves.

RESULTS

Data from 1095 patients (549, naldemedine; 546, placebo) were analyzed. The area under the curve for the receiver operating characteristic curves (ranges, 0.719 to 0.798 for PAC-SYM and 0.734 to 0.833 for PAC-QOL) indicated that both instruments can discriminate responders and nonresponders for each anchor. PAC-SYM cutoff values ranged from -1.04 to -0.83; PAC-QOL cutoff values ranged from -0.93 to -0.82.

CONCLUSIONS

Based on data derived from the anchor method, reductions in PAC-SYM and PAC-QOL scores of >1.0 in patients with chronic noncancer pain and opioid-induced constipation are clinically meaningful.

CLINICALTRIALS

gov Registration: NCT01965158; NCT01993940.

Use of naldemedine is associated with reduced incidence of hyperactive delirium in cancer patients with opioid-induced constipation: a nationwide retrospective cohort study in Japan

BACKGROUND

Medical benefits of peripherally-acting mu-opioid receptor antagonists other than improving opioid-induced constipation remain unclear. Our aim was to evaluate the association between the use of naldemedine and incidence of hyperactive delirium in cancer patients receiving chemotherapy and opioid therapy.

METHODS

We conducted a propensity score-matched analysis using a nationwide inpatient database in Japan. Cancer patients receiving both inpatient chemotherapy and opioid therapy from June 1, 2017 to March 31, 2018 were included. Patients receiving naldemedine were matched to control patients by propensity score. Our primary outcome was the incidence of hyperactive delirium during hospitalization, and secondary outcomes were the length of hospital stay, hospital costs, in-hospital mortality, and incidence of ileus.

RESULTS

Of 34,031 patients receiving inpatient chemotherapy and opioid therapy, 1905 (5.6%) were included in the naldemedine group. After one-to-four propensity score matching, 1904 patients were included in the naldemedine group and 7616 in the control group. Naldemedine users had significantly reduced incidence of hyperactive delirium compared with the control patients (19.4% vs 23.3%; risk difference, -3.9 [95% confidence interval, -5.9 - -1.9]; risk ratio, 0.83 [0.75-0.92]; P<0.001; subdistribution hazard ratio, 0.85 [0.75-0.97]; P=0.015). The median length of hospital stay was significantly shorter in the naldemedine group compared with the control group (12 days [interquartile range, 6-23] vs 14 days [6-26]; P=0.001). The median hospital costs were also significantly lower in the naldemedine group compared with the control group (US $6179 [3351-10,026] vs US $6576 [3436-11,107]; P<0.001). No significant differences were found for in-hospital mortality or incidence of ileus between the groups.

CONCLUSIONS

Our findings suggest that the use of naldemedine may have benefits in preventing hyperactive delirium, shortening hospital stay, and decreasing hospital costs in cancer patients receiving chemotherapy and opioid therapy.

Can Naloxegol Therapy Improve Quality of Life in Patients with Advanced Cancer?

This observational study aims to evaluate the efficacy of naloxegol therapy in resolving opioid-induced constipation (OIC) and in improving the quality of life in a home palliative care cancer setting. Advanced cancer patients with OIC (Rome IV criteria) not relieved by laxatives started a naloxegol therapy 25 mg/day for 4 weeks. Quality of life was evaluated by Patient Assessment of Constipation Quality-of-Life (PAC-QoL) at day 0 and day 28; background pain by Numerical Rating Scale, number of weekly spontaneous bowel movements and Bowel Function Index (BFI) were evaluated at day 0 and every week. Seventy-eight patients who completed the 4-week study improved all four PAC-QoL dimensions (physical and psychological discomfort, worries/concerns and satisfaction level). Weekly spontaneous bowel movements increased and BFI improved. Background pain reduced after seven days and remained lower during the following weeks. Seventy-two patients dropped out the study before day 28 with a reduced survival compared to patients completing the study. Even in these patients, an improvement of bowel function was observed after two weeks. Naloxegol was effective in improving the quality of life, resolving OIC and reducing overall pain in patients with advanced cancer.

Naldemedine is effective in the treatment of opioid-induced constipation in patients with chronic non-cancer pain who had a poor response to laxatives

BACKGROUND

Two studies demonstrated the efficacy and safety of naldemedine in adult patients with chronic non-cancer pain and opioid-induced constipation (OIC). However, no studies have compared the efficacy of peripherally acting µ-opioid receptor antagonists in patients with adequate and inadequate responses to prior OIC therapy with laxatives. This post hoc analysis of integrated data from the two previous studies compared the efficacy of naldemedine in patients who were unsuccessfully treated with laxatives [poor laxative responders (PLRs)] with those who either did not receive laxatives >30 days prior to screening or those who only received rescue laxative at or after screening (non-PLRs).

METHODS

Patients with OIC were randomized to once-daily treatment with naldemedine 0.2 mg or placebo. The primary efficacy endpoint was the proportion of responders [⩾3 spontaneous bowel movements (SBMs)/week and an increase from baseline of ⩾1 SBM/week for ⩾9 weeks of the 12-week treatment period and ⩾3 weeks of the final 4 weeks of the 12-week treatment period]. Additional endpoints included change in SBM frequency, change in frequency of SBMs without straining, proportion of complete SBM (CSBM) responders, change in CSBM frequency, and time to first SBM. Treatment-emergent adverse events (TEAEs) were assessed.

RESULTS

The analysis included 538 (317 PLRs, 221 non-PLRs) and 537 (311 PLRs, 226 non-PLRs) patients in the naldemedine and placebo arms, respectively. There were significantly more responders in the naldemedine PLR (46.4%; p < 0.0001) and non-PLR (54.3%; p = 0.0009) subgroups versus the placebo groups (30.2% and 38.9%, respectively). In both the PLR and non-PLR subgroups, naldemedine treatment was superior to placebo on all additional endpoints. Overall incidence of TEAEs in the PLR subgroups treated with naldemedine or placebo was similar.

CONCLUSION

This integrated analysis further supports the efficacy and tolerability of naldemedine in the treatment of OIC and demonstrates a consistent effect in both PLR and non-PLR subgroups.[ClinicalTrials.gov identifier: NCT01965158 and NCT01993940].

Efficacy and Safety of Peripherally Acting μ-Opioid Receptor Antagonist (PAMORAs) for the Management of Patients With Opioid-Induced Constipation: A Systematic Review

In treating chronic and acute pain, opioids are widely used. Although they do provide analgesia, their usage does come with adverse events (AEs). One of the most burdensome is opioid-induced bowel dysfunction, and more specifically opioid-induced constipation (OIC). The pathogenesis of these AEs is well known as the consequence of the action of opioids on m-receptors in the enteric nervous system. In recent years, medicines counteracting this specific action at the receptors have been registered for clinical use: the peripherally acting μ-opioid receptor antagonists (PAMORAs). The knowledge of their comparative efficacy and tolerability is very important for physicians and patients in opioid therapy. This systematic review of the existing literature on PAMORAs aimed to study the relative clinical advantages and disadvantages. The most important data banks, including "PubMed," "Embase," "CT.gov," "ICTRP" and "CINAHL" were used to find the published material on PAMORAs. The selected publications were examined to systematically analyze the efficacy and safety of the four existing PAMORAs. All of the medications are superior to placebo in reducing OIC. There are few published data on alvimopan used to treat OIC, and it is only indicated for the treatment of post-abdominal surgery ileus. Methylnaltrexone is studied mainly in its subcutaneous (SC) formulation. When used in its oral formulation, it seems more rapid than naloxegol and placebo in the reduction of OIC. Naldemedine is able to produce more spontaneous bowel movements (SBMs) when compared to alvimopan and naloxegol. Tolerability was found to be similar for all of them. In particular, they affect the gastrointestinal tract (GI), with flatulence and diarrhea, especially at high dosages. For some of them, nasopharyngitis and abdominal pain were observed as treatment adverse effects (TEAs). Several cardiovascular TEAs were reported after methylnaltrexone use, but it is not clear whether they were consequences of the drug or related to the general conditions of the patients. Considering the existing data, naloxegol and naldemedine seem to be the best choices, with a higher number of spontaneous bowel movements following naldemedine administration.

Insights into the Use of Peripherally Acting μ-Opioid Receptor Antagonists (PAMORAs) in Oncologic Patients: from Scientific Evidence to Real Clinical Practice

OPINION STATEMENT

Management of chronic pain is crucial to improve the quality of life of cancer and palliative care patients. Opioid-based treatments used to control pain can be prolonged over time. Unfortunately, constipation is one of the most disturbing adverse effects of long-term use of opioids. Opioid-induced constipation (OIC) occurs when opioids bind to the specific receptors present in the gastrointestinal (GI) tract, and can affect any patients receiving chronic opioid therapy, including cancer patients. The limited efficacy of laxatives to treat OIC symptoms prompted the search for new therapeutic strategies. Peripherally acting μ-opioid receptor antagonists (PAMORAs) have recently emerged as new effective drugs for OIC management due to their specific binding to enteric μ-receptors. Little information is available on the use of PAMORAs in real-life practice for OIC treatment in cancer patients. In this paper, a panel of experts specializing in cancer and palliative care pools their clinical experience with PAMORAs in cancer patients presenting OIC and highlights the importance of timing and choice of therapy in achieving prompt OIC management and benefitting patients.

Magnesium Oxide in Constipation

Magnesium oxide has been widely used as a laxative for many years in East Asia, yet its prescription has largely been based on empirical knowledge. In recent years, several new laxatives have been developed, which has led to a resurgence in interest and increased scientific evidence surrounding the use of magnesium oxide, which is convenient to administer, of low cost, and safe. Despite these advantages, emerging clinical evidence indicates that the use of magnesium oxide should take account of the most appropriate dose, the serum concentration, drug-drug interactions, and the potential for side effects, especially in the elderly and in patients with renal impairment. The aim of this review is to evaluate the evidence base for the clinical use of magnesium oxide for treating constipation and provide a pragmatic guide to its advantages and disadvantages.

Systematic review with meta-analysis: efficacy and safety of treatments for opioid-induced constipation

BACKGROUND

When opioid-induced constipation is treated with centrally acting opioid antagonists, there may be opioid withdrawal or aggravation of pain due to inhibition of μ-opioid analgesia. This led to the development of peripherally acting μ-opioid receptor antagonists (PAMORAs).

AIM

To evaluate the efficacy of available PAMORAs and other approved or experimental treatments for relieving constipation in patients with opioid-induced constipation, based on a systematic review and meta-analysis of published studies.

METHODS

A search of MEDLINE, EMBASE and EBM Reviews Cochrane Central Register of Controlled Trials was completed in July 2019 for randomised trials compared to placebo. FDA approved doses or highest studied dose was evaluated. Efficacy was based on diverse endpoints, including continuous variables (the bowel function index, number of spontaneous bowel movements and stool consistency based on Bristol Stool Form Scale), or responder analysis (combination of >3 spontaneous bowel movements or complete spontaneous bowel movements plus 1 spontaneous bowel movement or complete spontaneous bowel movements, respectively, over baseline [so-called FDA endpoints]). Adverse effects evaluated included central opioid withdrawal, serious adverse events, abdominal pain and diarrhoea.

RESULTS

We included 35 trials at low risk of bias enrolling 13 566 patients. All PAMORAs demonstrated efficacy on diverse patient response endpoints. There was greater efficacy with approved doses of the PAMORAs (methylnaltrexone, naloxegol and naldemidine), with lower efficacy or lower efficacy and greater adverse effects with combination oxycodone with naloxone, lubiprostone and linaclotide.

CONCLUSIONS

Therapeutic response in opioid-induced constipation is best achieved with the PAMORAs, methylnaltrexone, naloxegol and naldemidine, which are associated with low risk of serious adverse events.

Efficacy of naloxegol on symptoms and quality of life related to opioid-induced constipation in patients with cancer: a 3-month follow-up analysis

Objectives

Opioid-induced constipation (OIC) can affect up to 63% of all patients with cancer. The objectives of this study were to assess quality of life as well as efficacy and safety of naloxegol, in patients with cancer with OIC.

Methods

An observational study was made of a cohort of patients with cancer and with OIC exhibiting an inadequate response to laxatives and treated with naloxegol. The sample consisted of adult outpatients with a Karnofsky performance status score ≥50. The Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL) and the Patient Assessment of Constipation Symptoms (PAC-SYM) were applied for 3 months.

Results

A total of 126 patients (58.2% males) with a mean age of 61.3 years (range 34–89) were included. Clinically relevant improvements (>0.5 points) were recorded in the PAC-QOL and PAC-SYM questionnaires (p<0.0001) from 15 days of treatment. The number of days a week with complete spontaneous bowel movements increased significantly (p<0.0001) from 2.4 to 4.6 on day 15, 4.7 after 1 month and 5 after 3 months. Pain control significantly improved (p<0.0001) during follow-up. A total of 13.5% of the patients (17/126) presented some gastrointestinal adverse reaction, mostly of mild (62.5%) or moderate intensity (25%).

Conclusions

Clinically relevant improvements in OIC-related quality of life, number of bowel movements and constipation-related symptoms were recorded as early as after 15 days of treatment with naloxegol in patients with cancer and OIC, with a good safety profile.

European society of neurogastroenterology and motility guidelines on functional constipation in adults

INTRODUCTION

Chronic constipation is a common disorder with a reported prevalence ranging from 3% to 27% in the general population. Several management strategies, including diagnostic tests, empiric treatments, and specific treatments, have been developed. Our aim was to develop European guidelines for the clinical management of constipation.

DESIGN

After a thorough review of the literature by experts in relevant fields, including gastroenterologists, surgeons, general practitioners, radiologists, and experts in gastrointestinal motility testing from various European countries, a Delphi consensus process was used to produce statements and practical algorithms for the management of chronic constipation.

KEY RESULTS

Seventy-three final statements were agreed upon after the Delphi process. The level of evidence for most statements was low or very low. A high level of evidence was agreed only for anorectal manometry as a comprehensive evaluation of anorectal function and for treatment with osmotic laxatives, especially polyethylene glycol, the prokinetic drug prucalopride, secretagogues, such as linaclotide and lubiprostone and PAMORAs for the treatment of opioid-induced constipation. However, the level of agreement between the authors was good for most statements (80% or more of the authors). The greatest disagreement was related to the surgical management of constipation.

CONCLUSIONS AND INFERENCES

European guidelines on chronic constipation, with recommendations and algorithms, were developed by experts. Despite the high level of agreement between the different experts, the level of scientific evidence for most recommendations was low, highlighting the need for future research to increase the evidence and improve treatment outcomes in these patients.

Opioid-Induced Constipation in Oncological Patients: New Strategies of Management

OPINION STATEMENT

Cancer-associated pain has traditionally been treated with opioid analgesics, often in escalating doses. Opioid-induced constipation (OIC) is a common problem associated with chronic use of opioid analgesics. Typical treatment strategies to alleviate constipation are based on dietary changes, exercise, and laxatives. However, laxatives have a nonspecific action and do not target underlying mechanisms of OIC. This article will review prevalent, clinical presentation and recommendations for the treatment of OIC. An independent literature search was carried out by the authors. We reviewed the literature for randomized controlled trials that studied the efficacy of laxatives, naloxone, and naloxegol in treating OIC. Newer strategies addressing the causal pathophysiology of OIC are needed for a more effective assessment and management of OIC. Finally, traditional recommended therapies are appraised and compared with the latest pharmacological developments. Future research should address whether naloxegol is more efficacious by its comparison directly with first-line treatments, including laxatives.

Combining opioids and non-opioids for pain management: Current status

Pain remains a global health challenge. For decades, clinicians have been primarily relying on μ-opioid receptor (MOR) agonists and nonsteroidal anti-inflammatory drugs (NSAIDs) for pain management. MOR agonists remain the most efficacious analgesics available; however, adverse effects related to MOR agonists use are severe which often lead to forced drug discontinuation and inadequate pain relief. The recent opioid overdose epidemic urges the development of safer analgesics. Combination therapy is a well-established clinical pharmacotherapeutic strategy for the treatment of various clinical disorders. The combination of MOR agonists with non-MOR agonists may increase the analgesic potency of MOR agonists, reduce the development of tolerance and dependence, reduce the diversion and abuse, overdose, and reduce other clinically significant side effects associated with prolonged opioid use such as constipation. Overall, the combination therapy approach could substantially improve the therapeutic profile of MOR agonists. This review summarizes some recent developments in this field. This article is part of the Special Issue entitled 'New Vistas in Opioid Pharmacology'.

Targeting mu opioid receptors to modulate gastrointestinal function: what have we learnt so far from the studies in functional bowel disorders?

Opioids have recently received much attention because of the epidemic in their use in some countries such as the USA and the UK. Concerns have been raised about the possibility that they can increase mortality in patients when used on a long-term basis. Moreover, they are known to induce paradoxical hyperalgesia as well as alterations of gut function. The analgesic properties of opioids are mediated by receptors located in the brain, but as opioid receptors are also expressed in the gastrointestinal tract, new drugs acting on these receptors have recently been developed to treat two functional disorders, namely irritable bowel syndrome with diarrhoea and opioid-induced constipation. The aim of this article is to highlight some interesting observations resulting from the development of these drugs in the field of functional gastrointestinal disorders.

Clinical Overview and Considerations for the Management of Opioid-induced Constipation in Patients With Chronic Noncancer Pain

OBJECTIVES

Opioid analgesics may be associated with chronic adverse effects, such as opioid-induced constipation (OIC). Available and emerging prescription medications for OIC in patients with chronic noncancer pain are described, including concerns and challenges associated with OIC management.

METHODS

Narrative review.

RESULTS

OIC is characterized by a change in bowel habits and defecation patterns that occurs when initiating opioid therapy and is associated with reduced bowel frequency, straining, sensation of incomplete evacuation, and/or patient distress related to bowel habits. Prescription medications are indicated when OIC persists despite conservative approaches (eg, increased fiber and fluid intake, exercise, over-the-counter laxatives and stool softeners). Phase 3 studies have demonstrated the efficacy of peripherally acting µ-opioid receptor antagonists (PAMORA; methylnaltrexone, naloxegol, naldemedine), and a chloride channel activator (lubiprostone) for improving OIC in patients with chronic noncancer pain. Although head-to-head studies are lacking, a meta-analysis demonstrated that μ-opioid receptor antagonists were more effective than placebo for the treatment of OIC. The most common adverse effects associated with prescription medications for OIC are gastrointestinal related (eg, nausea, diarrhea, abdominal pain, or distention), with most being mild or moderate in severity. Therapy currently in development for OIC includes the PAMORA axelopran.

DISCUSSION

Health care providers should be aware of this complication in patients receiving opioids and should monitor and address constipation-related symptoms to optimize pain management and improve patient quality of life.

Pharmacological Treatment of Opioid-Induced Constipation Is Effective but Choice of Endpoints Affects the Therapeutic Gain

BACKGROUND

Widespread opioid use has led to increase in opioid-related adverse effects like constipation. We examined the impact of study endpoints on reported treatment benefits.

METHODS

Using MEDLINE, EMBASE, and ClinicalTrials.gov, we searched for randomized control trials targeting chronic opioid-induced constipation (OIC) and subjected them to meta-analysis. Data are given with 95% confidence intervals.

RESULTS

Thirty trials met our inclusion criteria. Combining all dichotomous definitions of responders, active drugs were consistently more effective than placebo, with an odds ratio (OR): 2.30 [2.01-2.63; 15 studies], independent of the underlying drug mechanism. The choice of endpoints significantly affected the therapeutic gain. When time from drug administration to defecation was used, the OR decreased from 4.74 [2.71-4.74] at 6 h or less to 2.46 [1.80-3.30] at 24 h (P < 0.05). Using other response definitions, the relative benefit over placebo was 2.10 [1.77-2.50; 12 studies] for weekly bowel frequency, 2.03 [1.39-2.95; 9 studies] for symptom scores, 2.21 [1.25-3.90; 4 studies] for global assessment scales, and 1.27 [0.79-2.03; 7 studies] for rescue laxative use.

CONCLUSION

While treatment of OIC with active drugs is more effective than placebo, the relative gain depends on the choice of endpoints. The commonly used time-dependent response definition is associated with the highest response rate but is of questionable relevance in a chronic disorder. The limited data do not clearly demonstrate a unique advantage of the peripherally restricted opioid antagonists, suggesting that treatment with often cheaper agents should be optimized before shifting to these novel expensive agents.

New developments in the treatment of opioid-induced gastrointestinal symptoms

Chronic pain affects a large part of the global population, leading to an increase of opioid use. Opioid-induced constipation (OIC), a highly prevalent adverse effect of opioid use, has a major impact on patients' quality of life. Thanks to the introduction of new drugs for chronic constipation, which can also be used in OIC, and the development of peripherally acting mu-opioid receptor blockers, specifically for use in OIC, therapeutic options have seen major development. This review summarises current and emerging treatment options for OIC based on an extensive bibliographical search. Efficacy data for laxatives, lubiprostone, prucalopride, linaclotide, oxycodone/naloxone combinations, methylnaltrexone, alvimopan, naloxegol, naldemedine, axelopran, and bevenopran in OIC are summarised.

Opioid receptors in the GI tract: targets for treatment of both diarrhea and constipation in functional bowel disorders?

Opioids have been used for centuries, mostly as a sedative and to treat pain. Currently, they are used on a global scale for the treatment of acute and chronic pain in diseases as osteoarthritis, fibromyalgia, and low back pain. Binding of opioids on opioid receptors can cause a range of different effects such as changes in stress response, analgesia, motor activity and autonomic functions. This review provide a synthetic summary of the most recent literature on the use of drugs acting on mu-receptors to treat two prevalent functional bowel disorders, presenting with opposite bowel habit. Eluxadoline and naloxegol, methylnaltrexone and naldemedine are recently FDA and/or EMA approved drugs demonstrated to be effective and safe for treatment respectively of irritable bowel syndrome subtype diarrhea and opioid induced constipation.

Naloxegol to Treat Constipation in a Patient Taking Opioids for Cancer Pain: A Case Report

Opioid-induced constipation (OIC) is a common gastrointestinal adverse effect of opioids, which can severely affect compliance and adherence to pain medication regimens and quality of life. Naloxegol has demonstrated efficacy against OIC in several studies involving patients with nonmalignant chronic pain. Here we report efficacy and tolerability of naloxegol in a 68-year-old patient with metastatic lung cancer and severe pain, treated with opioids, who presented with OIC resistant to traditional measures. Addition of naloxegol produced rapid improvement in his OIC symptoms and no apparent adverse effects while taking extended-release morphine 130 mg orally every 12 hours.

Medical Therapy of Constipation: Current Standards and Beyond

Chronic constipation is a very common medical problem with relevant impact on the patients' quality of life. Modern definitions recognize constipation as a polysymptomatic disorder, including various aspects of disturbed defecation. Current guidelines recommend a stepwise approach in the management of chronic constipation. Isolated or concomitant evacuation disorders should be identified and may need differential/additional treatment. Baseline measures include lifestyle components and bulking agents. The next step recommends treatment with conventional laxatives. In refractory patients, modern medical therapies, such as the prokinetic prucalopride or the secretagogues linalotide or lubiprostone, may be used effectively. For patients with opioid-induced constipation, the modern concept of peripherally acting µ-opioid antagonists has shown to successfully improve this increasing medical problem and even to potentially increase survival time in terminally ill patients on opioid therapy. Prolonged-released oral naloxone (in fixed combination with oxycodone), oral naloxegol or naldemedine, and subcutaneous methylnaltrexone have all demonstrated good efficacy and tolerability in the treatment of opioid-induced constipation. To adequately apply stepwise treatment algorithms, a simple tool to identify treatment failure may improve patient care.

The impact of naloxegol on anal sphincter function - Using a human experimental model of opioid-induced bowel dysfunction

BACKGROUND AND AIMS

Opioid treatment interferes with anal sphincter function and its regulation during defecation. This may result in straining, incomplete evacuation, and contribute to opioid-induced bowel dysfunction (OIBD). Employing an experimental model of oxycodone-induced OIBD, we hypothesized that co-administration of the peripherally acting μ-opioid antagonist naloxegol would improve anal sphincter function in comparison to placebo.

METHODS

In a double-blind randomized crossover trial, 24 healthy males were assigned to a six-day treatment of oral oxycodone 15 mg twice daily in combination with either oral naloxegol 25 mg once daily or placebo. At baseline and at day 6, anal resting pressure and the recto-anal inhibitory reflex (RAIR) were evaluated using manometry and rectal balloon distension. Furthermore, the functional lumen imaging probe was used to measure distensibility of the anal canal. Gastrointestinal symptoms were assessed with the Patient Assessment of Constipation Symptom (PAC-SYM) questionnaire and the Bristol Stool Form Scale.

RESULTS

During oxycodone treatment, naloxegol improved RAIR-induced sphincter relaxation by 15% (-45.9 vs -38.8 mm Hg; P < 0.01). No differences in anal resting pressure and anal canal distensibility were found between treatments (all P > 0.5). Naloxegol improved PAC-SYM symptoms (mean score over days; 2.6 vs 4.5, P < 0.001) and improved stool consistency scores (mean score over days; 3.3 vs 2.9, P < 0.01).

CONCLUSIONS

In this experimental model of OIBD, naloxegol improved the RAIR and reduced gastrointestinal symptoms. Hence, in contrast to conventional laxatives, naloxegol may regulate opioid-induced anal sphincter dysfunction and facilitate the defecation process.

Peripherally acting μ-opioid receptor antagonists as treatment options for constipation in noncancer pain patients on chronic opioid therapy

Opioid-induced constipation (OIC), a prevalent and distressing side effect of opioid therapy, does not reliably respond to treatment with conventional laxatives. OIC can be a treatment-limiting adverse event. Recent advances in medications with peripherally acting μ-opioid receptor antagonists, such as methylnaltrexone, naloxegol, and alvimopan, hold promise for treating OIC and thus extending the benefits of opioid analgesia to more chronic pain patients. Peripherally acting μ-opioid receptor antagonists have been clinically tested to improve bowel symptoms without compromise to pain relief, although there are associated side effects, including abdominal pain. Other treatment options include fixed-dose combination products of oxycodone analgesic together with naloxone.

Translating Clinical Findings into the Patient's Perspective: Post-hoc Pooled Analysis of Bowel Movement Changes as a Predictor of Improvement in Patients' Opioid-induced Constipation Symptoms and Outcomes

PURPOSE

Opioid-induced constipation (OIC) is a bothersome side effect of opioid use for the management of noncancer pain, affecting patients' health-related quality of life and chronic-pain management. The objective of this study was to examine the relationship between changes in the frequency of spontaneous bowel movements (SBMs) and changes in patient-reported outcomes (PROs) among patients with OIC treated with naloxegol.

METHODS

Post hoc analyses were conducted using pooled data from two Phase III 12-week, placebo-controlled trials of naloxegol for the treatment of OIC (NCT01309841 and NCT01323790). Patients completed the Patient Assessment of Constipation-Quality of Life (PAC-QOL) and PAC-Symptoms (PAC-SYM) at each study visit, and the Straining Scale and Bristol Stool Scale (BSS) with each bowel movement for the study duration. Four subgroups were created based on improvements from baseline in mean frequency of SBMs per week: 0 or worse (no change), +1 SBM, +2 SBMs, and +≥3 SBMs. Spearman correlations assessed the association between mean SBM changes from baseline and mean changes from baseline in PROs; analysis of covariance was used to compare changes from baseline.

FINDINGS

A total of 1337 patients with mean (SD) age of 52.2 (11.0) years were included in this analysis. The patient population was predominantly white (79.0%) and female (62.4%). At baseline, mean SBM frequency was 1.4 (1.0) per week. At study end, all 4 SBM-change subgroups experienced improvements in PAC-QOL, PAC-SYM, Straining Scale, and BSS scores, and these changes were significantly correlated with mean changes from baseline in SBMs per week. The subgroup of patients with an increase in SBMs of ≥3 per week experienced the greatest improvements in PROs.

IMPLICATIONS

In these patients with OIC, an improvement in the frequency of SBMs by ≥3 per week was associated with consistent improvements in PROs, providing support for the use of improvements in SBMs as a clinical outcome surrogate for managing patients with OIC. Further research is needed to determine a threshold for change in SBMs that is clinically meaningful in both research and clinical settings. A key limitation was the post hoc nature of the study, which was not powered prospectively to examine these relationships.

The role of naloxegol in the management of opioid-induced bowel dysfunction

Opioid-induced constipation (OIC) and other gastrointestinal (GI) symptoms of opioid-induced bowel dysfunction (OIBD) significantly deteriorate patients' quality of life and may lead to noncompliance with opioid schedule and undertreatment of pain. Although traditional oral laxatives are the first-line treatment of OIC, they do not address OIBD pathophysiology, and display numerous adverse effects. OIC treatment includes prokinetics (lubiprostone), opioid switch, and changing route of opioid administration. Targeted management of OIBD comprises the use of purely peripherally acting μ-opioid receptor antagonists (PAMORA): naloxegol and methylnaltrexone. Naloxegol (NKTR-118) is a polymer conjugate of the opioid antagonist naloxone. The polyethylene glycol limits naloxegol capacity to cross the blood-brain barrier (BBB). Naloxegol is substrate for the P-glycoprotein (P-gp) transporter. The central nervous system penetration of naloxegol is negligible due to reduced permeability and its increased efflux across the BBB, related to P-gp transporter. Naloxegol antagonizes μ- and κ-opioid receptors and displays low affinity to δ-opioid receptors in the GI tract, thereby decreasing OIBD symptoms without reversing central analgesic effects. Naloxegol is metabolised through CYP3A4 to six metabolites, with the majority of the dose (68%) excreted with faeces and less (16%) with urine. The dose of naloxegol equals 25 mg administered orally once daily on a fasting condition. Mild or moderate hepatic impairment has no impact on naloxegol dosing; naloxegol was not studied and is not recommended in patients with hepatic failure. Dose reduction (12.5 mg once daily) and caution is recommended in patients with moderate-to-severe renal impairment. Efficacy (bowel movement in 42-49% of patients not responsive to laxatives) and safety of naloxegol were confirmed in studies conducted in patients with OIC and nonmalignant pain. Naloxegol may be useful for cancer patients with OIC, although studies in this population are lacking.

Impact of Treatment with Naloxegol for Opioid-Induced Constipation on Patients' Health State Utility

Introduction

Opioid-induced constipation (OIC) is the most common side effect of opioid treatment. Treatment for OIC typically involves a laxative. However, some patients have an inadequate response to these (laxative inadequate responders, or LIR). This has led to the development of treatments such as naloxegol. This analysis estimates the impact of naloxegol on the health state utility of LIR patients, examines if this utility impact is driven by the change in OIC status, and estimates the utility impact of relief of OIC.

Methods

The analysis was conducted using data from two 12-week randomized controlled trials, KODIAC 4 (ClinicalTrials.gov identifier, NCT01309841) and KODIAC 5 (ClinicalTrials.gov identifier, NCT01323790), plus KODIAC 7 (ClinicalTrials.gov identifier, NCT01395524), a 12-week extension to KODIAC 4. All were designed to assess the efficacy and safety of oral naloxegol (12.5 and 25 mg) compared to placebo. Health state utility data were collected through the EuroQol—five dimensions questionnaire (EQ-5D-3L). Descriptive analysis was undertaken to estimate how EQ-5D utility scores and EQ-5D domain responses varied with treatment, OIC status, and over time. A repeated measure mixed-effects model was used to predict the change from baseline in health state utility score over time.

Results

Compared with placebo, LIR patients treated with naloxegol 25 mg reported a 0.08 improvement in the EQ-5D overall score after 12 weeks of treatment. The analyses also suggest that change in OIC status is a key driver of the impact of OIC treatment on health state utility. When other factors are controlled, relieving OIC is associated with a 0.05 improvement in health state utility, although treatment with naloxegol is associated with an improvement in health state utility over and above the improvement in OIC status.

Conclusion

These analyses suggest that treatment with naloxegol improves patients’ health state utility; driven predominantly by the relief of patients’ constipation.

Funding

AstraZeneca.

Constipation in Elderly Patients with Noncancer Pain: Focus on Opioid-Induced Constipation

Constipation is a common and often debilitating condition in the elderly, which may be caused by underlying disease conditions, structural abnormalities in the bowel, and a variety of medications such as anticholinergics, antidepressants, and opiates. In this review, we focus on opioid-induced constipation (OIC), which is often underrecognized and undertreated in the elderly. When opioid therapy is initiated, healthcare providers are encouraged to evaluate risk factors for the development of constipation as part of a thorough patient history. To this end, the patient assessment should include the use of validated instruments, such as the Bristol Stool Scale and Bowel Function Index, to confirm the diagnosis and provide a basis for evaluating treatment outcomes. Healthcare providers should use a stepwise approach to the treatment of OIC in the elderly. Conventional laxatives are a first-line option and considered well tolerated with short-term use as needed; however, evidence is lacking to support their effectiveness in OIC. Moreover, because of the risk of adverse events and other considerations, such as chewing difficulties and swallowing disorders, conventional oral laxatives may be inappropriate for the treatment of OIC in the elderly. Thus, the availability of new pharmacologic agents such as the peripherally acting µ-opioid receptor antagonists methylnaltrexone and naloxegol, which target the underlying causes of OIC, and the secretagogue lubiprostone may provide more effective treatment options for elderly patients with OIC.

Definition, diagnosis and treatment strategies for opioid-induced bowel dysfunction–Recommendations of the Nordic Working Group

Background and aims

Opioid-induced bowel dysfunction (OIBD) is an increasing problem due to the common use of opioids for pain worldwide. It manifests with different symptoms, such as dry mouth, gastro-oesophageal reflux, vomiting, bloating, abdominal pain, anorexia, hard stools, constipation and incomplete evacuation. Opioid-induced constipation (OIC) is one of its many symptoms and probably the most prevalent. The current review describes the pathophysiology, clinical implications and treatment of OIBD.

Methods

The Nordic Working Group was formed to provide input for Scandinavian specialists in multiple, relevant areas. Seven main topics with associated statements were defined. The working plan provided a structured format for systematic reviews and included instructions on how to evaluate the level of evidence according to the GRADE guidelines. The quality of evidence supporting the different statements was rated as high, moderate or low. At a second meeting, the group discussed and voted on each section with recommendations (weak and strong) for the statements.

Results

The literature review supported the fact that opioid receptors are expressed throughout the gastrointestinal tract. When blocked by exogenous opioids, there are changes in motility, secretion and absorption of fluids, and sphincter function that are reflected in clinical symptoms. The group supported a recent consensus statement for OIC, which takes into account the change in bowel habits for at least one week rather than focusing on the frequency of bowel movements. Many patients with pain receive opioid therapy and concomitant constipation is associated with increased morbidity and utilization of healthcare resources. Opioid treatment for acute postoperative pain will prolong the postoperative ileus and should also be considered in this context. There are no available tools to assess OIBD, but many rating scales have been developed to assess constipation, and a few specifically address OIC. A clinical treatment strategy for OIBD/OIC was proposed and presented in a flowchart. First-line treatment of OIC is conventional laxatives, lifestyle changes, tapering the opioid dosage and alternative analgesics. Whilst opioid rotation may also improve symptoms, these remain unalleviated in a substantial proportion of patients. Should conventional treatment fail, mechanism-based treatment with opioid antagonists should be considered, and they show advantages over laxatives. It should not be overlooked that many reasons for constipation other than OIBD exist, which should be taken into consideration in the individual patient.

Conclusion and implications

It is the belief of this Nordic Working Group that increased awareness of adverse effects and OIBD, particularly OIC, will lead to better pain treatment in patients on opioid therapy. Subsequently, optimised therapy will improve quality of life and, from a socio-economic perspective, may also reduce costs associated with hospitalisation, sick leave and early retirement in these patients.