Dose-finding study of linaclotide in Japanese patients with chronic constipation: A phase II randomized, double-blind, and placebo-controlled study

Examining linaclotide for the treatment of chronic idiopathic constipation

INTRODUCTION

Chronic idiopathic constipation (CIC) is characterized by infrequent bowel movements and hard stools lasting for at least three months or longer. This disease affects 8-12% of the US population and 10-17% of the world population. Treatment and management involve identifying the primary cause, changing dietary habits, and adequate physical activity. Linaclotide is a guanylate cyclase-agonist acting locally in the luminal surface of the intestinal enterocyte leading to a signal transduction cascade, activation of the cystic fibrosis transmembrane conductance regulator (CFTR), thus increasing secretion of chloride and bicarbonate into the intestinal lumen with eventual increased intestinal fluid and faster transit time.

AREAS COVERED

We reviewed multiple studies and did a thorough literature review on CIC including its pathophysiology. Through this literature review, we were able to discuss and give the context and rationale for drug regimens indicated for CIC.

EXPERT OPINION

The era we live in right now is akin to nutrient-rich and fertilized soil as knowledge and resources are abundant. The opportunities and potential are endless. Constipation being more extensively studied, our understanding of medications and diseases broadens, leading to novel medications being discovered. Linaclotide is a pioneer in this aspect and can pave the way for future generations.

Clinical effects of chemical drugs, fecal microbiota transplantation, probiotics, dietary fiber, and acupuncture in the treatment of chronic functional constipation: a systematic review and network meta-analysis

Currently, there are increasingly diverse treatment modalities for chronic functional constipation (CFC). This study aims to compare the relative efficacy and safety of chemical drugs, fecal microbiota transplantation (FMT), probiotics, dietary fiber, and acupuncture in the treatment of patients with CFC. We searched relevant randomized controlled trials (RCTs) published in five databases up to November 2023. Network meta-analysis (NMA) was carried out using R Studio 4.2.1. Cumulative ranking probability plots, assessed through the surface under the cumulative ranking (SUCRA), were employed to rank the included drugs for various outcome measures. We included a total of 45 RCT studies with 17 118 patients with CFC. From the SUCRA values and NMA results FMT showed the best utility in terms of clinical efficacy, Bristol stool form scale scores, patient assessment of constipation quality of life scores, and the treatment modality with the lowest ranked incidence of adverse effects was electroacupuncture. Subgroup analysis of the chemotherapy group showed that sodium A subgroup analysis of the chemical group showed that sodium picosulfate 10 mg had the highest clinical efficacy. FMT is more promising in the treatment of CFC and may be more effective in combination with the relatively safe treatment of acupuncture.

Nocebo effects and influencing factors in the randomized clinical trials of chronic constipation: A systematic review and meta-analysis

BACKGROUND

Nocebo effects are unavoidable in randomized clinical trials. We aimed to assess the magnitude of nocebo effects and explore the influencing factors in chronic constipation.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases up to July 2022. Randomized, placebo-controlled trials investigating interventions in chronic constipation were included. We conducted a random effects meta-analysis of the proportion of adverse events (AEs) in placebo-treated participants and evaluated the effect of trial characteristics on nocebo effects.

KEY RESULTS

We identified 20,204 studies from the databases, of which 61 were included in the final analysis. The pooled placebo AE rate was 30.41%, and AE-related withdrawal rate was 1.53%. The most commonly reported AEs were headache (5.67%), diarrhea (4.45%), abdominal pain (3.98%), nasopharyngitis (3.39%), nausea (3.36%), and flatulence (2.95%). The placebo AE rate was lower in trials conducted in Asia compared to those in Europe, North America, and international trials. It was also lower in trials diagnosed by Rome III compared to clinician's opinion and Rome II. Additionally, the placebo AE rate was lower in single-center trials compared to multicenter trials, lower in 5-8 weeks therapy compared to 9-12 weeks therapy, lower in participants with FC compared to those with IBS-C and CC, lower in trials with 2 arms compared to 3 arms, and higher in trials with prokinetic drugs compared to secretagogues and laxatives.

CONCLUSIONS & INFERENCES

The placebo AE rate was 30.41% in patients with chronic constipation. Based on our findings, we recommend that researchers take the nocebo effects into consideration when designing and conducting clinical trials and adopt specific measures to mitigate the negative influence of nocebo effects.

Comparative profiles of lubiprostone, linaclotide, and elobixibat for chronic constipation: a systematic literature review with meta-analysis and number needed to treat/harm

OBJECTIVE

To comprehensively evaluate the efficacy, safety, patient symptoms, and quality-of-life (QoL) of lubiprostone, linaclotide, and elobixibat as treatment for chronic constipation (CC).

DESIGN

Systematic literature review (SLR) and meta-analysis (MA). Literature searches were conducted on PubMed and Embase using the Ovid platform.

METHODS

SLR including randomized controlled trials (RCTs) and observational studies was conducted to identify the overall efficacy and safety of lubiprostone, linaclotide, and elobixibat. Thereafter, MA was performed using only RCTs. The number needed to treat (NNT) and number needed to harm (NNH) analyses were additionally conducted.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was efficacy regarding change in spontaneous bowel movements. Secondary outcomes included safety, constipation-related symptoms, and QoL.

RESULTS

Twenty-four studies met the inclusion criteria for the SLR: 17 RCTs, 4 observational studies, and 3 single-arm trials. Feasibility assessment for the MA resulted in 14 studies available for safety data analysis, and 8 available for efficacy analysis, respectively. Three drugs showed similar efficacy in the MA and NNT analysis. However, the NNH analysis revealed distinct safety profiles: lubiprostone, linaclotide, and elobixibat were linked to the highest risk of nausea, diarrhea, and abdominal pain, respectively.

CONCLUSION

The current study provides an updated overview of the efficacy, safety, patient symptoms, and QoL of the three drugs with different mechanisms of action for CC treatment.The findings could help physicians adopt an individualized approach for treating patients with CC in clinical practice.

Current Management of Chronic Constipation in Japan

Constipation is a complicated condition. Chronic constipation is diagnosed when constipation occurs for more than 3 months. Chronic constipation is classified using patient symptoms and the pathophysiology. New therapeutic agents to treat chronic constipation have recently been approved in Japan. However, treatments for constipation that is refractory to traditional laxatives have been approved, an algorithm for the treatment of chronic constipation has not yet been developed. The accumulation of knowledge and data is necessary to develop a new algorithm.

Effects of linaclotide in the treatment of chronic constipation and irritable bowel syndrome with constipation: a meta-analysis

OBJECTIVE

Linaclotide is a guanylate cyclase-C (GCC) agonist that is found in intestinal epithelial cells and is used when treating chronic constipation (CC) and irritable bowel syndrome with constipation (IBS-C). Several randomized controlled trials (RCTs) were conducted for evaluating its efficacy and safety.

METHODS

The PubMed, EMBASE, and Cochrane databases and the Web of Science were searched to find multiple RCTs of patients with CC or IBS-C. The Jadad scoring system was used for evaluating each study's methodological quality, and RevMan5.3 was used for meta-analysis. The composite endpoint reaction approved by the FDA, abdominal pain and discomfort relief, symptom improvement, and diarrhea-related adverse reactions were chosen as observation indicators, and relative risk (RR) and 95% confidence interval (CI) were obtained for quantitative and comprehensive evaluation.

RESULTS

Eleven randomized controlled studies were included, consisting of 5 cases of CC and 6 cases of IBS-C. Linaclotide reached the composite endpoint response approved by FDA in the treatment of CC (RR = 3.26, 95% CI: 2.45-4.33), and the composite endpoint response approved by FDA for the treatment of IBS-C (RR = 2.26, 95% CI: 1.86-2.74) was greater than the placebo (both p < 0.00001). The main adverse reactions of linaclotide were gastrointestinal, mostly diarrhea, which was higher than that of the placebo when treating CC (RR = 3.56, 95% CI: 2.76-4.60) and IBS-C (RR = 8.23, 95% CI: 5.69-11.90) (both p < 0.00001).

CONCLUSION

Linaclotide proved to be effective and safe for the treatment of CC and IBS-C compared to the placebo. However, diarrhea is the primary adverse reaction.

A Systematic Review and Network Meta-Analysis on the Efficacy of Medications in the Treatment of Chronic Idiopathic Constipation in Japan

Background

In the 2010s, medications with new mechanisms were introduced in Japan for the treatment of chronic idiopathic constipation (CIC). A few systematic reviews have compared medications' relative efficacy, but the reviews included studies on patients from various races, even though the mechanism of CIC is considered to differ between races. The aim of this study was to use a systematic review and network meta-analysis to compare the relative efficacy of these medications in Japanese patients.

Methods

We conducted a meta-analysis and report it here according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We identified studies by searching MEDLINE (via the PubMed interface) and the Cochrane Library and ICHUSHI databases and included randomized clinical trials that compared medications for CIC with placebo in Japanese adults. Two reviewers independently screened and assessed articles, abstracted data, and assessed the risk of bias. We pooled data by random-effects meta-analyses and also performed a Bayesian network meta-analysis to indirectly compare data.

Results

The present systematic review and meta-analyses included 1460 patients in 6 randomized clinical trials: 2 on linaclotide, 3 on elobixibat, 2 on lubiprostone, and 1 on lactulose. The results of direct comparisons showed that linaclotide, elobixibat, and lubiprostone were superior to placebo in the change of spontaneous bowel movements (SBMs) within 1 week: linaclotide, 1.95 (95% CI, 1.51-2.39); elobixibat, 5.69 (95% CI, 3.31-8.07); and lubiprostone, 2.41 (95% CI, 0.82-4.01). The Bayesian network meta-analysis showed consistent results. Elobixibat 10 mg was ranked first for the increase in SBMs and complete SBMs within 1 week and the time to first SBM. Lubiprostone 48 μg was ranked first for the proportion of patients with SBM within 24 hours.

Conclusion

Our direct and indirect meta-analyses revealed that the new CIC medications available in Japan have equal efficacy but that elobixibat and lubiprostone are highly likely to be more efficacious.

Comparison of the Efficacy and Safety of Different Doses of Linaclotide for Patients with Chronic Constipation: A Meta-Analysis and Bayesian Analysis

BACKGROUND

It is ambiguous whether a higher dose of linaclotide provides higher efficacy for chronic constipation (CC) patients. The meta-analysis aimed to assess the efficacy and safety of linaclotide doses ranging from 62.5 μg to 600 μg for CC patients.

METHODS

A comprehensive search was conducted, and STATA16 software was used for data analysis.

RESULTS

Seven studies with 4,107 patients were eligible. A significantly enhanced number of completely spontaneous bowel movement (CSBM) responders were found in the extremely low-dose group (OR: 2.94; 95% CI: 1.98-4.34; p < 0.001), the low-dose group (OR: 3.24; 95% CI: 2.44-4.31; p < 0.001), the medium-dose group (OR: 3.08; 95% CI: 1.46-6.50; p=0.003), and high-dose group (OR: 4.79; 95% CI: 3.04-7.54; p < 0.001). Bayesian analysis showed the high-dose group obtained the maximum CSBM responder rate (OR: 4.94; 95% credible interval (CrI): 3.22-7.79; probability rank = 0.87) indirectly compared with extremely low-dose, low-dose, and medium-dose groups. However, no significant difference presented in the CSBM responder rate by pairwise comparisons of the different dose groups. Additionally, no more any adverse events occurred in the higher linaclotide dose group (RR: 0.91; 95% CrI: 0.60-1.38) indirectly compared with other dose groups.

CONCLUSIONS

High dose of linaclotide could be more effective and safer for CC patients, which need more trials to confirm in the future.

Safety of elobixibat and lubiprostone in Japanese patients with chronic constipation: a retrospective cohort study

BACKGROUND

We aimed to discuss and compare reported adverse reactions and drug add-ons associated with elobixibat and lubiprostone use in chronic constipation treatment, as the safety of these drugs has not been well examined in post-marketing clinical settings.

RESEARCH DESIGN AND METHODS

In this retrospective cohort study, using records of community pharmacies in Japan, we identified new users of elobixibat and lubiprostone. The Japan Pharmaceutical Association sent questionnaires regarding baseline and event data to community pharmacists. The incidence of events and hazard ratio (HR) associated with the study drugs were evaluated.

RESULTS

New users of elobixibat (n = 979) and lubiprostone (n = 829) were identified (mean age: 74 and 77 years; females: 59% and 53%, respectively). Although the crude risk ratio of adverse events for elobixibat was 0.79 (95% confidence interval: 0.63-0.99), there was no significant difference in the HR for any of the common events, including drug add-ons (n ≥ 5), compared with those for lubiprostone.

CONCLUSION

No new safety concerns have been raised in relation to elobixibat and lubiprostone use for treating chronic constipation, although the HR of different events varied. Further larger-scale study is needed as the estimates for events of small numbers were unstable.

[Efficacy and Safety of Linaclotide in Elderly Patients]

The efficacy and safety of linaclotide in elderly patients are poorly understood. Herein, we aimed to assess the efficacy and safety of linaclotide in elderly patients in real-world setting. We retrospectively enrolled consecutive patients who started linaclotide therapy at Sapporo Medical University Hospital from October 1, 2017 to December 31, 2019. The efficacy and safety of linaclotide were examined in relation to various factors, including age (<65 or ≥65 years) and dose (0.25 or 0.5 mg/d). Fifty-two patients were enrolled, 60% of whom were over 65 years old and 40% were female. Thirty-six patients received a linaclotide dose of 0.25 mg/d. The most common side effect was diarrhea, but there was no difference in the incidence of diarrhea between the elderly (64.5%) and non-elderly patients (42.9%, p=0.130). No significant difference was observed with respect to improvement in constipation in the elderly (83.9%) and non-elderly patients (71.4%, p=0.318). Additionally, the difference in efficacy of linaclotide in patients who received a reduced dose (80.6%) vs. those who received the recommended dose (75.0%) was not statistically significant (p=0.719). Multivariate analysis revealed that age, gender, and dose were not associated with diarrhea induced by linaclotide treatment. However, concurrent treatment with constipation-inducing medications [odds ratio (OR) 5.79, p=0.047] and linaclotide monotherapy (OR 11.1, p=0.040) were both risk factors contributing to diarrhea. Linaclotide is effective and safe for use in elderly patients. The incidence of diarrhea may increase when linaclotide is administered alone or concurrently used with medications that cause constipation.

[Pharmacological and clinical profile of linaclotide (Linzess®), a novel therapeutic agent for irritable bowel syndrome with constipation and chronic constipation]

Linaclotide (Linzess^® tablets 0.25 mg) is a guanylate cyclase-C (GC-C) agonist with high selectivity and binding affinity to GC-C. In Japan, linaclotide was approved for 〝irritable bowel syndrome with constipation (IBS-C)〟 in December 2016 and 〝chronic constipation (CC) (excluding constipation due to organic disease)〟 in August 2018. Non-clinical studies demonstrated that linaclotide binding to GC-C increases intracellular cyclic guanosine monophosphate (cGMP), resulting in increased fluid secretion and gastrointestinal transit. In rats with colonic hyperalgesia, but not in normal rats, linaclotide suppressed the visceral nociceptive response, mediated by increased submucosal cGMP. In clinical studies in Japan, improvements were observed in the responder rates for global assessment of IBS symptom relief, complete spontaneous bowel movements in patients with IBS-C, and the frequency of spontaneous bowel movement in patients with CC, which were maintained during long-term treatment. Additionally, abdominal bloating, which has been associated with lower quality of life (QOL) and lower satisfaction with other approved therapies, and IBS QOL were improved throughout treatment with linaclotide. Diarrhea, a consequence of linaclotide's mechanism of action, was observed during the clinical studies, but was generally controllable by decreasing the linaclotide dose. No drug resistance was observed during the clinical studies, unlike some other approved agents. These results of non-clinical and clinical studies demonstrate that linaclotide can improve constipation, various abdominal symptoms, and QOL with a favorable safety profile in patients with IBS-C and CC.

High-dose linaclotide is effective and safe in patients with chronic constipation: A phase III randomized, double-blind, placebo-controlled study with a long-term open-label extension study in Japan

BACKGROUND

A previous phase II dose-ranging study of linaclotide in a Japanese chronic constipation (CC) population showed that 0.5 mg was the most effective dose. This study aimed to verify the hypothesis that 0.5 mg of linaclotide is effective and safe in Japanese CC patients.

METHODS

This was a Japanese phase III randomized, double-blind, placebo-controlled (part 1), and long-term, open-label extension (part 2) study of linaclotide. CC patients (n = 186) diagnosed using the Rome III criteria were randomly assigned to linaclotide 0.5 mg (n = 95) or placebo (n = 91) for a 4-week double-blind treatment period in part 1, followed by an additional 52 weeks of open-label treatment with linaclotide in part 2. The primary efficacy endpoint was the change from baseline in weekly spontaneous bowel movement (SBM) frequency at the first week. Secondary endpoints included responder rate for complete SBM (CSBM), changes in stool consistency, and severity of straining.

KEY RESULTS

Part 1: Change in weekly mean SBM frequency in the first week of treatment with linaclotide (4.02) was significantly greater than that with placebo (1.48, P < 0.001). Linaclotide produced a higher CSBM responder rate (52.7%) compared to placebo (26.1%, P < 0.001). Part 2: Patients continued to show improved SBM frequency with linaclotide. Through parts 1 and 2, the most common drug-related adverse event was mild and occasionally moderate diarrhea.

CONCLUSIONS AND INFERENCES

The results of this study indicate that a linaclotide dose of 0.5 mg/day is effective and safe in Japanese CC patients.