Psychometric Evaluation of the Diary for Irritable Bowel Syndrome Symptoms-Constipation in a Prospective Observational Study.

OBJECTIVES: To evaluate the psychometric properties of the Diary for Irritable Bowel Syndrome Symptoms-Constipation (DIBSS-C), which was developed to support primary and secondary endpoints in irritable bowel syndrome (IBS) with predominant constipation (IBS-C) clinical trials. METHODS: Observational data were collected from 108 adults with IBS-C using a smartphone-type device for 17 days. DIBSS-C data regarding bowel movements (BMs) were collected for each event (along with the Bristol Stool Form Scale); abdominal symptoms were rated each evening. Global status items and the Gastrointestinal Symptom Rating Scale-IBS were completed on day 10 and day 17 and the IBS-Symptom Severity Scale on day 17. Item-level performance, internal consistency reliability, test-retest reliability, and construct validity were evaluated. RESULTS: The Abdominal Symptoms Domain score demonstrated high internal consistency reliability (Cronbach's alpha week 1 = 0.98; week 2 = 0.96) and test-retest reliability (intraclass correlation coefficient [ICC] = 0.93). Test-retest reliability was stronger for abdominal symptoms (ICC = 0.91-0.94) than for the frequency-based BM-related outcomes (ICC = 0.54-0.66). Key construct validity hypotheses were supported by moderate to strong correlations with the corresponding Gastrointestinal Symptom Rating Scale-IBS, IBS-Symptom Severity Scale, and Bristol Stool Form Scale items. All known-groups comparisons were statistically significant for the abdominal symptom items and domain score; evidence for known-groups validity of BM-related outcomes was supportive when based on constipation severity. CONCLUSIONS: The results of this study provided key psychometric evidence for the DIBSS-C, ultimately contributing to its qualification by the US Food and Drug Administration for use in IBS-C clinical trials.

A Review of Patient-Reported Outcome Labeling of FDA-Approved New Drugs (2016-2020): Counts, Categories, and Comprehensibility.

OBJECTIVES: A review of new drug approvals (NDAs) by the US Food and Drug Administration (FDA) for 2006 to 2015 showed that approximately 20% of new drugs had labeling based on patient-reported outcomes (PROs). The purpose of this study was to review labeling text based on PRO endpoints for NDAs from 2016 to 2020, with a special focus on the comprehensibility of such statements when included. METHODS: We reviewed drug approval reports on the Drugs@FDA web page of the FDA website to determine the number of NDAs from 2016 to 2020. For all identified NDAs, drug approval package and product labels were reviewed. NDAs from 2016 to 2020 were grouped by disease category as per International Classification of Diseases 10th Revision. Data were summarized for diseases that traditionally rely on PROs for evaluating treatment benefit (PRO dependent) and for diseases that traditionally do not rely on PROs (non-PRO dependent). Results were compared with NDAs from 2006 to 2010. RESULTS: NDAs amounting to 228 were identified from 2016 to 2020, 26.3% of which had labeling statements based on PRO endpoints. From 2006 to 2015 and from 2016 to 2020, PRO labeling statements were included in 46.5% (46 of 99) and 50.0% (47 of 94), respectively, of NDAs for PRO-dependent new molecular entities and in 6.0% (12 of 199) and 9.7% (13 of 199), respectively, of NDAs for non-PRO-dependent new molecular entities. Comprehensibility of labeling statements based on PRO endpoints was judged to be complex in 56.7% of product labels. CONCLUSIONS: The increase in labeling text based on PRO endpoints in product labels is encouraging. However, there is room for improvement on the comprehensibility of labeling statements based on PRO endpoints.

Psychometric Analysis of the Abdominal Score From the Diary for Irritable Bowel Syndrome Symptoms-Constipation Using Phase IIb Clinical Trial Data.

OBJECTIVES: The Diary for Irritable Bowel Syndrome Symptoms-Constipation (DIBSS-C) has been developed to assess the core signs and symptoms of irritable bowel syndrome with constipation (IBS-C). This article presents the psychometric evaluation of the DIBSS-C abdominal score. METHODS: Data for these analyses are from a multicenter phase IIb study in IBS-C patients (NCT02559206). Subjects completed a number of assessments via handheld electronic diary throughout the study. The analyses used the intent-to-treat population and were blinded to randomized treatment group. The analyses evaluated the reliability, validity, and responsiveness of the DIBSS-C abdominal score; identified an appropriate scoring algorithm; and determined thresholds for interpreting clinically meaningful changes at the individual level. RESULTS: The correlations between the DIBSS-C abdominal symptom items (ie, abdominal pain, discomfort, and bloating) were strong (>0.75). Cronbach's alpha for the abdominal symptom severity items was very strong (.94), indicating that the 3 abdominal symptom items produce a reliable score. The intraclass correlation coefficient for the abdominal score was 0.82, exceeding the threshold of 0.70 and indicating good test-retest reliability. Guyatt's responsiveness statistic values all exceeded the threshold for a large effect of 0.80, so the DIBSS-C abdominal score can be considered highly responsive to change. Triangulation across 3 sets of anchor-based analyses indicated that a threshold of -2.0 points on the abdominal score is an appropriate threshold for identifying meaningful change. CONCLUSIONS: Overall, this study provides evidence that the DIBSS-C abdominal score is valid, reliable, responsive to change, and interpretable for assessing treatment benefit in patients with IBS-C.

The Impact of Stool Consistency on Bowel Movement Satisfaction in Patients With IBS-C or CIC Treated With Linaclotide or Other Medications: Real-World Evidence From the CONTOR Study.

GOALS: This study aimed to characterize the impact of stool consistency on patient-reported bowel movement (BM) satisfaction in patients with irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation, with a focus on linaclotide. BACKGROUND: As new medications for constipation become available, understanding patients' perceptions of treatment effects may help clinicians manage patient expectations and inform clinical decision-making. MATERIALS AND METHODS: Data were derived from the Chronic Constipation and IBS-C Treatment and Outcomes Real-world Research Platform (CONTOR) study from 2 patient-reported 7-day daily BM diaries to create a dataset of 2922 diaries representing 26,524 BMs for 1806 participants. Binary variables were created for: medication(s) used in the past 24 hours and categorization of BMs as loose or watery stools (LoWS), hard or lumpy stools (HoLS), or intermediate (neither LoWS nor HoLS). The relationship between stool consistency, medication use, and BM satisfaction was analyzed using logistic regression with SEs corrected for repeated observations. RESULTS: BMs characterized as intermediate stools and LoWS were satisfactory more often (61.2% and 51.2%, respectively) than HoLS (19.4%). Participants who reported taking linaclotide rated a similar proportion of BMs as satisfactory when described as LoWS (65.6%) or intermediate (64.1%). Linaclotide use was associated with higher odds of BMs being reported as satisfactory compared with nonlinaclotide use (odds ratio: 1.23, P<0.05). CONCLUSIONS: Overall, CONTOR participants were more likely to report BMs classified as LoWS or intermediate as satisfactory, versus HoLS. Participants taking linaclotide were more likely to be satisfied, particularly those reporting LoWS, versus those not taking linaclotide.

The impact of treatment with eluxadoline on health-related quality of life among adult patients with irritable bowel syndrome with diarrhea.

PURPOSE: Irritable bowel syndrome with diarrhea (IBS-D) significantly impacts health-related quality of life (HRQOL). This post hoc analysis of two phase III trials evaluated the effects of eluxadoline treatment on disease-specific HRQOL among patients with IBS-D. METHODS: Adult patients meeting Rome III criteria for IBS-D were randomized to oral eluxadoline (75 mg or 100 mg) or placebo twice daily in two phase III clinical trials for 52 weeks (IBS-3001) and 26 weeks (IBS-3002). The Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire assessed disease-specific HRQOL throughout the study. Changes from baseline to Week 26 in IBS-QOL total and subscale scores were analyzed using an analysis of covariance model. Percentages of IBS-QOL responders with ≥ 14- and 20-point changes were evaluated for IBS-QOL total and subscale scores. A longitudinal mixed-effects model was fitted to evaluate mean IBS-QOL total scores. A cumulative distribution function for change from baseline to Week 26 in IBS-QOL total score was plotted. RESULTS: Mean changes from baseline to Week 26 for the IBS-QOL total and all subscale scores were significantly higher for patients treated with eluxadoline (both doses) compared to placebo. A significantly greater proportion of eluxadoline-treated patients were responders compared to placebo. Mean and mixed-effects model estimated mean IBS-QOL total scores were consistently higher for eluxadoline versus placebo over 52 weeks. CONCLUSIONS: Compared to placebo, twice-daily eluxadoline treatment significantly improved HRQOL among patients with IBS-D in two phase III trials.

Development of a Symptom-Focused Patient-Reported Outcome Measure for Functional Dyspepsia: The Functional Dyspepsia Symptom Diary (FDSD).

OBJECTIVES: The Functional Dyspepsia Symptom Diary (FDSD) was developed to address the lack of symptom-focused, patient-reported outcome (PRO) measures designed for use in functional dyspepsia (FD) patients and meeting Food and Drug Administration recommendations for PRO instrument development. METHODS: Concept elicitation interviews were conducted with FD participants to identify symptoms important and relevant to FD patients. A preliminary version of the FDSD was constructed, then completed by FD participants on an electronic device in cognitive interviews to evaluate the readability, comprehensibility, relevance, and comprehensiveness of the FDSD, and to preliminarily evaluate its measurement properties. RESULTS: During concept elicitation interviews, 45 participants spontaneously reported 19 symptom concepts. Of those, seven symptoms were selected for assessment by the eight-item FDSD. Cognitive interviews with 57 participants confirmed that participants were able to comprehend and provide meaningful responses to the FDSD, and that the handheld electronic FDSD format was suitable for use in the target population. Scores of the FDSD were well-distributed among response options, item discrimination indices suggested that the FDSD items differentiate among patients with varying degrees of FD severity, and inter-item correlations suggested that no items of the FDSD were capturing redundant information. Internal consistency estimates (0.87) and construct-related validity estimates using known-groups methods were within acceptable ranges. CONCLUSIONS: The FDSD is a content-valid PRO measure, with preliminary psychometric evidence providing support for the FDSD's items and total score. Further psychometric evaluations are recommended to more fully test the FDSD's score performance and other measurement properties in the target patient population.

Health Care Resource Use and Costs Pre- and Post-Treatment Initiation With Linaclotide: Retrospective Analyses of a U.S. Insured Population.

As expected, pharmacy costs increased with the introduction of this new treatment in a market dominated by over-the-counter and generic treatments. On the other hand, outpatient GI-related and irritable bowel disease health care resource use and costs substantially decreased among commercial and Medicare patients following linaclotide treatment initiation.

Development of the Diary for Irritable Bowel Syndrome Symptoms to Assess Treatment Benefit in Clinical Trials: Foundational Qualitative Research.

BACKGROUND: Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain and alterations in bowel habits. Three subtypes are defined on the basis of stool patterns: diarrhea-predominant IBS, constipation-predominant IBS, and alternating or mixed IBS. OBJECTIVES: To develop patient-reported outcome measures for qualification by the Food and Drug Administration to support product approvals and labeling in IBS; the article focuses on the qualitative research that provided the foundation for the new measures. METHODS: Forty-nine concept elicitation and 42 cognitive debriefing interviews were conducted with subjects meeting Rome III criteria; additional criteria were imposed to yield a sample representative of the target patient population. RESULTS: Although incomplete bowel movements, abnormal stool frequency and consistency, and abdominal pain, discomfort, and bloating were reported most frequently across concept elicitation interviews, the relative importance of specific symptoms varied by subtype. Among their five symptoms most important to treat, diarrhea-predominant and alternating or mixed IBS subjects frequently identified urgency, loose/watery stools, abdominal pain, and cramping, whereas constipation-predominant IBS subjects commonly included infrequent and incomplete bowel movements, bloating, and abdominal pain. The cognitive debriefing interviews facilitated refinement of each item set, supported minor modifications following translatability assessment, and suggested improvements to the electronic interface. Furthermore, subjects reported that every item was relevant and no concepts of importance were missing. CONCLUSIONS: Results support the content validity of the IBS patient-reported outcome measures. A pilot study was recently initiated to inform item reduction, develop scoring algorithms, and provide preliminary psychometric information. Comprehensive psychometric evaluation and responder definition development will follow.

Health-related quality of life, work productivity, and indirect costs among patients with irritable bowel syndrome with diarrhea.

BACKGROUND: Irritable bowel syndrome (IBS) affects 10-15% of adults in the US, and is associated with significant impairment in health-related quality of life (HRQoL); however, information specific to the diarrhea subtype (IBS-D) is lacking. We assessed the impact of IBS-D on HRQoL, work productivity, and daily activities, and the associated indirect costs, among a sample of the US population. METHODS: Respondents (≥18 years) from the 2012 US National Health and Wellness Survey who reported an IBS-D diagnosis by a physician or symptoms consistent with Rome II criteria for IBS-D were identified as having IBS-D. Controls included respondents without IBS-D or inflammatory bowel disease. HRQoL was assessed via the Short Form 36 Health Survey version 2 questionnaire and summarized into Mental and Physical Component Summary (MCS; PCS) scores and a Short Form-6 dimension (SF-6D) utility score. Work and activity impairment were assessed via the Work Productivity and Activity Impairment Questionnaire: General Health version (WPAI:GH), which measures absenteeism, presenteeism, overall work productivity loss, and daily activity impairment. Indirect costs were calculated using unit cost data from the Bureau of Labor Statistics and variables from the WPAI:GH. Generalized linear models were used to examine differences in health outcomes between respondents with IBS-D and controls, controlling for demographic and health characteristics. RESULTS: In total, 66,491 respondents (1102 IBS-D; 65,389 controls) were analyzed. Mean age was 48.7 years; 50% were female. Compared with controls, the IBS-D cohort reported significantly lower HRQoL (mean MCS: 45.16 vs. 49.48; p < 0.001; mean PCS: 47.29 vs. 50.67; p < 0.001; mean SF-6D: 0.677 vs. 0.741; p < 0.001) and greater absenteeism (5.1% vs. 2.9%; p = 0.004), presenteeism (17.9% vs. 11.3%; p < 0.001), overall work productivity loss (20.7% vs. 13.2%; p < 0.001), and activity impairment (29.6% vs. 18.9%; p < 0.001). Respondents with IBS-D also incurred an estimated $2486 more in indirect costs ($7008 vs. $4522; p < 0.001). CONCLUSIONS: Compared with controls, IBS-D is associated with significantly lower HRQoL, greater impairments in work and daily activities, and higher indirect costs, imposing a substantial burden on patients and employers. These findings suggest a significant unmet need exists for effective IBS-D treatments.

Economic Evaluation of Linaclotide for the Treatment of Adult Patients With Chronic Idiopathic Constipation in the United States.

PURPOSE: To evaluate the effectiveness and costs of linaclotide (Linzess) versus lubiprostone (Amitiza) in the treatment of adult patients with chronic idiopathic constipation (CIC). DESIGN: A decision-tree model using model inputs derived from published literature, linaclotide phase 3 trial data, and a physician survey. METHODOLOGY: Measures of treatment efficacy were selected based on comparability between trial data, with posthoc analyses of linaclotide required to ensure comparability with available lubiprostone data. Response to therapy was defined as (1) having one of the best two satisfaction answers of a 5-point global treatment satisfaction scale at Week 4 or (2) having a weekly spontaneous bowel movement (SBM) frequency 4 at Week 4. Patients who do not respond to therapy are assumed to accrue costs associated with a treatment failure. Model time horizon is aligned with the lubiprostone clinical trial duration of 4 weeks. Model outputs include response rates, quality-adjusted life-years (QALYs) and direct costs. RESULTS: Linaclotide was associated with lower per-patient costs vs lubiprostone for both definitions of response ($946 vs $1,015 for global assessment and $727 vs $737 for SBM frequency). When treatment response was based on a global assessment of treatment satisfaction, linaclotide was associated with higher effectiveness (response: 39.3% vs 35.0%). For SBM frequency, linaclotide was slightly less effective compared to lubiprostone (response: 58.6% vs 59.6%), but also less costly. Base-case results were robust in sensitivity analysis. CONCLUSIONS: Linaclotide is less expensive with similar effectiveness when compared to lubiprostone for the treatment of CIC in adult patients.

Leveraging sensor-based functional outcomes to enhance understanding of the patient experience: challenges and opportunities.

INTRODUCTION: Sensor-based digital health technology (DHT) has emerged as a promising means to assess patient functioning within and outside clinical trials. Sensor-based functional outcomes (SBFOs) provide valuable insights that complement other measures of how a patient feels or functions to enhance understanding of the patient experience to inform medical product development. AREAS COVERED: This perspective paper provides recommendations for defining SBFOs, discusses the core evidence required to support SBFOs to inform decision-making, and considers future directions for the field. EXPERT COMMENTARY: The clinical outcome assessment (COA) development process provides an important starting point for developing patient-centered SBFOs; however, given the infancy of the field, SBFO development may benefit from a hybrid approach to evidence generation by merging exploratory data analysis with patient engagement in measure development. Effective SBFO development requires combining unique expertise in patient engagement, measurement and regulatory science, and digital health and analytics. Challenges specific to SBFO development include identifying concepts of interest, ensuring measurement of meaningful aspects of health, and identifying thresholds for meaningful change. SBFOs are complementary to other COAs and, as part of an integrated evidence strategy, offer great promise in fostering a holistic understanding of patient experience and treatment benefits, particularly in real-world settings.

Comprehensive assessment of patients with irritable bowel syndrome with constipation and chronic idiopathic constipation using deterministically linked administrative claims and patient-reported data: the Chronic Constipation and IBS-C Treatment and Outcomes Real-World Research Platform (CONTOR).

AIMS: To characterize a US population of patients with irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC) using CONTOR, a real-world longitudinal research platform that deterministically linked administrative claims data with patient-reported outcomes data among patients with these conditions. METHODS: Patients with IBS-C or CIC were identified using diagnosis and treatment codes from administrative claims. Potential respondents received a mailed survey followed by 12 monthly online follow-up surveys and 2 mailed diaries. Surveys collected symptom severity, treatment use, quality of life, productivity, and condition/treatment history. Comorbidities and healthcare costs/utilization were captured from claims data. Diaries collected symptoms, treatments, and clinical outcomes at baseline and 12 months. Data were linked to create a patient-centric research platform. RESULTS: Baseline surveys were returned by 2,052 respondents (16.8% response rate) and retention rates throughout the study were high (64.8%-70.8%). Most participants reported burdensome symptoms despite having complex treatment histories that included multiple treatments over many years. More than half (55.3%) were dissatisfied with their treatment regimen; however, a higher proportion of those treated with prescription medications were satisfied. LIMITATIONS: The study sample may have been biased by patients with difficult-to-treat symptoms as a result of prior authorization processes for IBS-C/CIC prescriptions. Results may not be generalizable to uninsured or older populations because all participants had commercial insurance coverage. CONCLUSIONS: By combining administrative claims and patient-reported data over time, CONTOR afforded a deeper understanding of the IBS-C/CIC patient experience than could be achieved with 1 data source alone; for example, participants self-reported burdensome symptoms and treatment dissatisfaction despite making few treatment changes, highlighting an opportunity to improve patient management. This patient-centric approach to understanding real-world experience and management of a chronic condition could be leveraged for other conditions in which the patient experience is not adequately captured by standardized data sources.

Development and psychometric evaluation of the Diabetic Gastroparesis Symptom Severity Diary.

BACKGROUND: Diabetic gastroparesis (DG) is defined as delayed gastric emptying with associated gastrointestinal symptoms, without mechanical obstruction. Patient-reported symptoms are critical for diagnosis and evaluation of treatment benefit in DG. The Diabetic Gastroparesis Symptom Severity Diary (DGSSD), a new patient-reported outcome measure, was developed for use in clinical trials to support product approval and labeling claims for DG treatments. MATERIALS AND METHODS: Initial DGSSD development was based on a review of the existing instruments and qualitative research (focus groups and cognitive debriefing interviews) in 41 patients with DG. Psychometric evaluations (individual items and composite scores) were conducted using data from Phase IIa and IIb relamorelin clinical trials. RESULTS: Qualitative research in patients with DG resulted in a six-item DGSSD, included in the Phase IIa trial, addressing symptom severity for nausea, vomiting, abdominal pain, early satiety, and bloating, as well as vomiting frequency. An item addressing severity of postprandial fullness (PPF) was subsequently added based on regulatory advice and included in the Phase IIb trial. Measurement properties were generally strong for weekly averages of daily item and composite scores. Item-level intraclass correlation coefficients ranged from 0.79 to 0.97 and correlations with other measures matched hypothesized patterns; the discriminating ability and responsiveness of the DGSSD were also supported. Multiple methods supported the computation of a composite score based on items addressing nausea, abdominal pain, bloating, and PPF severity. CONCLUSION: Qualitative and quantitative evidence support use of the DGSSD as a reliable and valid measure from which to derive endpoints to evaluate treatment benefit in future DG interventional trials.

Development of a Symptom-Based Patient-Reported Outcome Instrument for Functional Dyspepsia: A Preliminary Conceptual Model and an Evaluation of the Adequacy of Existing Instruments.

OBJECTIVES: The aim was to document, from the perspective of the empirical literature, the primary symptoms of functional dyspepsia (FD), evaluate the extent to which existing questionnaires target those symptoms, and, finally, identify any missing evidence that would impact the questionnaires' use in regulated clinical trials to assess treatment efficacy claims intended for product labeling. METHODS: A literature review was conducted to identify the primary symptoms of FD and existing symptom-based FD patient-reported outcome (PRO) instruments. Following a database search, abstracts were screened and articles were retrieved for review. The primary symptoms of FD were organized into a conceptual model and the PRO instruments were evaluated for conceptual coverage as well as compared against evidentiary requirements presented in the FDA's PRO Guidance for Industry. RESULTS: Fifty-six articles and 16 instruments assessing FD symptoms were reviewed. Concepts listed in the Rome III criteria for FD (n = 7), those assessed by existing FD instruments (n = 34), and symptoms reported by patients in published qualitative research (n = 6) were summarized in the FD conceptual model. Except for vomiting, all of the identified symptoms from the published qualitative research reports were also specified in the Rome III criteria. Only three of the 16 instruments, the Dyspepsia Symptom Severity Index (DSSI), Nepean Dyspepsia Index (NDI), and Short-Form Nepean Dyspepsia Index (SF-NDI), measure all seven FD symptoms defined by the Rome III criteria. Among these three, each utilizes a 2-week recall period and 5-point Likert-type scale, and had evidence of patient involvement in development. Despite their coverage, when these instruments were evaluated in light of regulatory expectations, several issues jeopardized their potential qualification for substantiation of a labeling claim. CONCLUSIONS: No existing PRO instruments that measured all seven symptoms adhered to the regulatory principles necessary to support product labeling. As such, the development of a new FD symptom PRO instrument is supported.

Economic evaluation of linaclotide for the treatment of adult patients with irritable bowel syndrome with constipation in the United States.

OBJECTIVES: To use techniques of decision-analytic modeling to evaluate the effectiveness and costs of linaclotide vs lubiprostone in the treatment of adult patients with irritable bowel syndrome with constipation (IBS-C). METHODS: Using model inputs derived from published literature, linaclotide Phase III trial data and a physician survey, a decision-tree model was constructed. Response to therapy was defined as (1) a ≥ 14-point increase from baseline in IBS-Quality-of-Life (IBS-QoL) questionnaire overall score at week 12 or (2) one of the top two responses (moderately/significantly relieved) on a 7-point IBS symptom relief question in ≥ 2 of 3 months. Patients who do not respond to therapy are assumed to fail therapy and accrue costs associated with a treatment failure. Model time horizon is aligned with clinical trial duration of 12 weeks. Model outputs include number of responders, quality-adjusted life-years (QALYs), and total costs (including direct and indirect). Both one-way and probabilistic sensitivity analyses were conducted. RESULTS: Treatment for IBS-C with linaclotide produced more responders than lubiprostone for both response definitions (19.3% vs 13.0% and 61.8% vs 57.2% for IBS-QoL and symptom relief, respectively), lower per-patient costs ($803 vs $911 and $977 vs $1056), and higher QALYs (0.1921 vs 0.1917 and 0.1909 vs 0.1894) over the 12-week time horizon. Results were similar for most one-way sensitivity analyses. In probabilistic sensitivity analyses, the majority of simulations resulted in linaclotide having higher treatment response rates and lower per-patient costs. LIMITATIONS: There are no available head-to-head trials that compare linaclotide with lubiprostone; therefore, placebo-adjusted estimates of relative efficacy were derived for model inputs. The time horizon for this model is relatively short, as it was limited to the duration of available clinical trial data. CONCLUSIONS: Linaclotide was found to be a less costly option vs lubiprostone for the treatment of adult patients with IBS-C.

Comparison of adequate relief with symptom, global, and responder endpoints in linaclotide phase 3 trials in IBS-C.

BACKGROUND: Optimal clinical trial endpoints for irritable bowel syndrome with constipation (IBS-C) are uncertain. OBJECTIVE: The objective of this article is to compare adequate relief (AR) to abdominal/bowel symptoms, global endpoints, and FDA and EMA responder criteria; and to use AR as an anchor to assess clinically meaningful change (CMC) in IBS-C symptoms. METHODS: Using pooled 12-week data from two phase 3 linaclotide clinical trials, daily abdominal/bowel symptoms and weekly global assessments were correlated with AR. Symptom CMC thresholds were estimated using AR as an anchor. Agreement between AR and FDA/EMA responder criteria was assessed. RESULTS: Correlations of AR with percentage change in abdominal symptoms, bowel symptoms, and global endpoints ranged from 0.48-0.54, 0.32-0.39, and 0.61-0.71, respectively. Using AR as an anchor, CMC thresholds were 29% improvement in abdominal pain, 29% improvement in abdominal discomfort, and 0.7/week increase in CSBMs, similar to thresholds for IBS-C responder endpoints recommended by the FDA and EMA. There was considerable agreement of weekly responder rates between AR and the FDA and EMA endpoints (on average, 70%-76% and 71%-82% of weeks with agreement, respectively). CONCLUSIONS: AR bridges IBS-C clinical trials, putting into perspective the disparate primary endpoints recommended by professional societies and regulatory authorities, and allowing researchers, practitioners, and regulators to compare trial results.

Impact of linaclotide treatment on work productivity and activity impairment in adults with irritable bowel syndrome with constipation: results from 2 randomized, double-blind, placebo-controlled phase 3 trials.

BACKGROUND: Irritable bowel syndrome with constipation (IBS-C), a chronic functional gastrointestinal disorder, has been shown to negatively affect work productivity and impair daily activity, resulting in a substantial burden for patients and employers. Linaclotide is a first-in-class guanylate cyclase-C agonist approved for the treatment of adults with IBS-C and chronic idiopathic constipation in the United States. OBJECTIVE: To analyze the impact of treatment with linaclotide on work productivity and daily activity impairment in adults with IBS-C and estimate the indirect costs associated with this condition. METHODS: This was a post-hoc analysis of data on IBS-C-related work time missed and work and activity impairment from 2 phase 3 clinical trials that assessed the efficacy and safety of linaclotide therapy in adults with IBS-C. The Work Productivity and Activity Impairment Questionnaire for IBS-C (WPAI:IBS-C) was self-administered at baseline and at weeks 4, 8, and 12 during the 12-week treatment periods in Trials 1 and 2 and at weeks 16, 20, and 26 during the extended treatment period in Trial 2. An analysis of covariance was conducted to assess changes from baseline to all study weeks for each WPAI:IBS-C measure. Indirect costs were calculated by converting overall work productivity losses into monetary values using the human capital cost approach. RESULTS: Of the 1602 patients with IBS-C who were randomized in the 2 clinical trials, 1555 (97.1%) completed a baseline and at least 1 postbaseline WPAI:IBS-C assessment and were included in the analysis cohort; 1148 (71.7%) of these patients were employed. Once-daily treatment with linaclotide significantly reduced overall work productivity loss and daily activity impairment among patients with IBS-C at all study weeks. From baseline to week 12, compared with placebo, linaclotide significantly reduced presenteeism by 5.2%, overall work productivity loss by 6.1%, and daily activity impairment by 4.7% (all P <.01) and led to a numerically greater decrease in absenteeism. From baseline to week 26, compared with placebo, reductions with linaclotide were 5.9% for presenteeism, 7.5% for overall work productivity loss, and 6.7% for daily activity impairment (all P <.05). Reductions in overall work productivity loss from baseline to week 26 translate to 103 hours to 156 hours annually and correspond to an avoided overall work loss of $3209 to $4861 annually for an employee with IBS-C. CONCLUSION: The results of this analysis indicate that appropriate treatment of IBS-C with medications such as linaclotide can reduce work-related impairment associated with IBS-C. In addition, IBS-C therapies that effectively manage this chronic condition and improve employees' quality of life and work productivity may represent significant cost-savings for employers in the form of avoided work productivity losses.

The economic burden of treatment failure amongst patients with irritable bowel syndrome with constipation or chronic constipation: a retrospective analysis of a Medicaid population.

OBJECTIVE: To compare healthcare resource utilization (HRU) and costs between patients with irritable bowel syndrome with constipation (IBS-C) or chronic constipation (CC) with and without evidence of treatment failure. METHODS: Claims data from the Missouri Medicaid program were used to identify adults with IBS-C or CC treated for constipation. IBS-C patients were required to have ≥2 constipation therapy claims, and the index date was defined as the date of the first constipation therapy claim within 12 months after an IBS diagnosis. For CC, the index date was defined as the date of the first constipation treatment claim followed by a second claim for constipation treatment or diagnosis between 60 days and 12 months later. Indicators of treatment failure were: switch/addition of constipation therapy, IBS- or constipation-related inpatient/emergency admission, megacolon/fecal impaction, constipation-related surgery/procedure, or aggressive prescription treatments. Annual incremental HRU and costs (public payer perspective) were compared between patients with and without treatment failure. Incidence rate ratios (IRRs) and cost differences are reported. RESULTS: In total, 2830 patients with IBS-C and 8745 with CC were selected. Approximately 50% of patients had ≥1 indicator of treatment failure. After adjusting for confounding factors, patients with treatment failure experienced higher HRU, particularly in inpatient days (IRR = 1.75 for IBS-C; IRR = 1.54 for CC) and higher total healthcare costs of $4353 in IBS-C patients and $2978 in CC patients. Medical service costs were the primary driver of the incremental costs associated with treatment failure, making up 71.3% and 67.0% of the total incremental healthcare costs of the IBS-C and CC samples, respectively. LIMITATIONS: Sample was limited to Medicaid patients in Missouri. Claims data were used to infer treatment failure. CONCLUSION: Treatment failure is frequent among IBS-C and CC patients, and sub-optimal treatment response with available IBS-C and CC therapies may lead to substantial HRU and healthcare costs.

Psychometric validation of patient-reported outcome measures assessing chronic constipation.

BACKGROUND: Measures assessing treatment outcomes in previous CC clinical trials have not met the requirements described in the US Food and Drug Administration's guidance on patient-reported outcomes. AIM: Psychometric analyses using data from one Phase IIb study and two Phase III trials of linaclotide for the treatment of chronic constipation (CC) were conducted to document the measurement properties of patient-reported CC Symptom Severity Measures. STUDY METHODS: Each study had a multicenter, randomized, double-blind, placebo-controlled, parallel-group design, comparing placebo to four doses of oral linaclotide taken once daily for 4 weeks in the Phase IIb dose-ranging study (n=307) and to two doses of linaclotide taken once daily for 12 weeks in the Phase III trials (n=1,272). The CC Symptom Severity Measures addressing bowel function (Bowel Movement Frequency, Stool Consistency, Straining) and abdominal symptoms (Bloating, Abdominal Discomfort, Abdominal Pain) were administered daily using interactive voice-response system technology. Intraclass correlations, Pearson correlations, factor analyses, F-tests, and effect sizes were computed. RESULTS: The CC Symptom Severity Measures demonstrated satisfactory test-retest reliability and construct validity. Factor analyses indicated one factor for abdominal symptoms and another for bowel symptoms. Known-groups F-tests substantiated the discriminating ability of the CC Symptom Severity Measures. Responsiveness statistics were moderate to strong, indicating that these measures are capable of detecting change. CONCLUSION: In large studies of CC patients, linaclotide significantly improved abdominal and bowel symptoms. These psychometric analyses support the reliability, validity, discriminating ability, and responsiveness of the CC Symptom Severity Measures for evaluating treatment outcomes in the linaclotide clinical studies.