The Efficacy of a Diet Low in Fermentable Oligo-, Di-, Monosaccharides, and Polyols in Irritable Bowel Syndrome Compared to Its "Real-world" Effectiveness: Protocol for a Systematic Review

BACKGROUND

Irritable bowel syndrome (IBS) is associated with various gastrointestinal and nongastrointestinal symptoms and reduced quality of life. A diet low in fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) is one therapeutic option for IBS. Although the efficacy of the low FODMAP diet has been reported in several systematic reviews, the efficacy-effectiveness gap of the low FODMAP diet has not yet been assessed.

OBJECTIVE

This systematic review aims to compare the efficacy of the low FODMAP diet from efficacy randomized controlled trials (RCTs) with the effectiveness of studies conducted in "real-world" settings.

METHODS

RCTs, prospective and retrospective cohort studies, and retrospective audits assessing the low FODMAP diet in adults with IBS will be searched in 4 databases: Embase, MEDLINE, CENTRAL, and CINAHL. Two independent reviewers will perform study selection, data extraction, and risk of bias assessment and assess selected quality aspects from the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) protocol. Outcomes assessed are stool frequency, stool consistency, abdominal pain, overall symptom scores, adequate symptom relief, IBS-specific quality of life, and diet adherence. Data will be summarized with forest plots without summary statistics, tables, and narrative descriptions.

RESULTS

The search, title and abstract screening, and full-text screening were completed in March 2021, and an updated search was done in May 2022. As of May 2023, data analysis is almost finished, and manuscript writing is in progress. Submission of the manuscript is expected by July 2023.

CONCLUSIONS

The findings of this systematic review will compare the efficacy of the low FODMAP diet for IBS found in RCTs to the diet's real-world effectiveness.

TRIAL REGISTRATION

PROSPERO CRD42021278952; https://tinyurl.com/32jk43ev.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/41399.

Combining individual patient data from randomized and non-randomized studies to predict real-world effectiveness of interventions

Meta-analysis of randomized controlled trials is generally considered the most reliable source of estimates of relative treatment effects. However, in the last few years, there has been interest in using non-randomized studies to complement evidence from randomized controlled trials. Several meta-analytical models have been proposed to this end. Such models mainly focussed on estimating the average relative effects of interventions. In real-life clinical practice, when deciding on how to treat a patient, it might be of great interest to have personalized predictions of absolute outcomes under several available treatment options. This paper describes a general framework for developing models that combine individual patient data from randomized controlled trials and non-randomized study when aiming to predict outcomes for a set of competing medical interventions applied in real-world clinical settings. We also discuss methods for measuring the models' performance to identify the optimal model to use in each setting. We focus on the case of continuous outcomes and illustrate our methods using a data set from rheumatoid arthritis, comprising patient-level data from three randomized controlled trials and two registries from Switzerland and Britain.

Real World Outcomes versus Clinical Trial Results of Durvalumab Maintenance in Veterans with Stage III Non-Small Cell Lung Cancer

Simple Summary

The standard of care for patients with stage III non-small cell lung cancer is concurrent chemoradiotherapy followed by maintenance durvalumab based on outcomes from the PACIFIC trial. The efficacy of this regimen in a real-world population has not been extensively studied. We found that the addition of durvalumab has significantly improved both progression-free and overall survival in veterans with stage III non-small cell lung cancer as compared to veterans who received concurrent chemoradiotherapy alone, but overall survival of veterans is reduced compared to patients in the PACIFIC trial. Additional studies will need to be performed to understand this efficacy-effectiveness gap.

Abstract

One year of durvalumab following concurrent chemoradiotherapy improves progression-free (PFS) and overall survival (OS) for patients with stage III non-small cell lung cancer (NSCLC). However, the real-world efficacy of durvalumab has not been determined. We conducted a multi-center observational cohort study across the Veterans Health Administration, including patients with stage III NSCLC who received concurrent chemoradiotherapy and durvalumab, compared to patients who received concurrent chemoradiotherapy alone. Kaplan–Meier and Cox regression approaches were used to identify factors associated with PFS and OS. We calculated a hazard ratio and efficacy-effectiveness factor to compare OS of veterans to the referenced clinical trial population. A total of 1006 patients with stage III NSCLC who received concurrent chemoradiotherapy and at least one dose of durvalumab from November 2017 to April 2021 were compared to 989 patients who received concurrent chemoradiotherapy alone from January 2015 to December 2016. Adjuvant durvalumab was associated with higher PFS (HR 0.62, 95% CI 0.55–0.70, p < 0.001) and OS (HR 0.57, 95% CI 0.50–0.66, p < 0.001). OS was shorter in veterans compared to PACIFIC (HR 1.24, 95% CI 1.03–1.48, p = 0.02: EE gap 0.73). OS of veterans with stage III NSCLC treated with adjuvant durvalumab is improved compared to a modern comparator but is reduced compared to the PACIFIC population.

Cancer clinical trial vs real-world outcomes for standard of care first-line treatment in the advanced disease setting

Clinical trials have strict eligibility criteria, potentially limiting external validity. However, while often discussed this has seldom been explored, particularly across cancer types and at variable time frames posttrial completion. We examined comprehensive registry data (January 2014 to June 2019) for standard first-line treatments for metastatic colorectal cancer (CRC), advanced pancreatic cancer (PC), metastatic HER2-amplified breast cancer (BC) and castrate-resistant prostate cancer (CaP). Registry patient characteristics and outcomes were compared to the practice-changing trial. Registry patients were older than the matched trial cohort by a median of 2-6 years (all P = <.01) for the CRC, BC and PC cohorts. The proportion of Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-1 patients was lower for CRC (94.1% vs 99.2%, P = .001) and BC (94.9% vs 99.3%, P = .001). Progression-free survival (PFS) for registry patients was similar to the trial patients or significantly longer (CaP, Hazard Ratio [HR] = 0.65, P = <.001). Overall survival (OS) was also similar or significantly longer (CaP, HR 0.49, P = <.001). In conclusion, despite real-world patients sometimes being older or having inferior PS to trial cohorts, the survival outcomes achieved were consistently equal or superior to those reported for the same treatment in the trial. We suggest that this is potentially due to optimised use of each treatment over time, improved multidisciplinary care and increased postprogression options. We can reassure clinicians and patients that outcomes matching or exceeding those reported in trials are possible. The potential for survival gains over time should routinely be factored into future trial statistical plans.

Prediction of Real-World Drug Effectiveness Prelaunch: Case Study in Rheumatoid Arthritis

BACKGROUND

Decision makers often need to assess the real-world effectiveness of new drugs prelaunch, when phase II/III randomized controlled trials (RCTs) but no other data are available.

OBJECTIVE

To develop a method to predict drug effectiveness prelaunch and to apply it in a case study in rheumatoid arthritis (RA).

METHODS

The approach 1) identifies a market-approved treatment ( S) currently used in a target population similar to that of the new drug ( N); 2) quantifies the impact of treatment, prognostic factors, and effect modifiers on clinical outcome; 3) determines the characteristics of patients likely to receive N in routine care; and 4) predicts treatment outcome in simulated patients with these characteristics. Sources of evidence include expert opinion, RCTs, and observational studies. The framework relies on generalized linear models.

RESULTS

The case study assessed the effectiveness of tocilizumab (TCZ), a biologic disease-modifying antirheumatic drug (DMARD), combined with conventional DMARDs, compared to conventional DMARDs alone. Rituximab (RTX) combined with conventional DMARDs was identified as treatment S. Individual participant data from 2 RCTs and 2 national registries were analyzed. The model predicted the 6-month changes in the Disease Activity Score 28 (DAS28) accurately: the mean change was -2.101 (standard deviation [SD] = 1.494) in the simulated patients receiving TCZ and conventional DMARDs compared to -1.873 (SD = 1.220) in retrospectively assessed observational data. It was -0.792 (SD = 1.499) in registry patients treated with conventional DMARDs.

CONCLUSION

The approach performed well in the RA case study, but further work is required to better define its strengths and limitations.

Real-World Effectiveness of Palbociclib Versus Clinical Trial Results in Patients With Advanced/Metastatic Breast Cancer That Progressed on Previous Endocrine Therapy

Objective:

The aim of this study was to assess the real-world effectiveness and tolerability of palbociclib combined with endocrine therapy for the treatment of hormone receptor positive (HR-positive), human epidermal growth factor receptor 2 negative (HER2-negative), advanced/metastatic breast cancer that progressed on previous endocrine therapy, and to compare these results with the outcomes of the PALOMA-3 clinical trial.

Methods:

This study was a retrospective observational cohort study including all patients who started with palbociclib in the St. Antonius Hospital between September 1, 2016 and April 1, 2018 for the treatment of HR-positive, HER2-negative advanced/metastatic breast cancer that progressed on previous endocrine therapy. Individual patient data were collected from electronic medical records. Primary study outcomes were progression-free survival (PFS) and the number of permanent treatment discontinuations before disease progression due to adverse events (AEs). Secondary outcomes were the frequency of all (serious) AEs and the frequency of and reasons for dose reductions, -interruptions and cycle delays.

Results:

A total of 46 patients were studied with a median follow-up of 13.0 months. Overall, the median PFS in real-world clinical practice was 10.0 months (95% confidence interval (CI) 4.9-15.1), compared with 9.5 months in PALOMA-3 (95% CI 9.2-11.0). Two patients discontinued treatment because of AEs. Neutropenia was the most frequent grade 3-4 AE, but with no febrile neutropenia events. Most AEs were managed with palbociclib dose modifications. Regarding these modifications, more cycle delays, less dose reductions, and less dose interruptions occurred in clinical practice compared with PALOMA-3 (59 vs 36%, 22 vs 34%, and 9 vs 54%, respectively). Patients who did not meet the PALOMA-3 study eligibility criteria (n = 16) showed a lower median PFS of 5.5 months (95% CI 4.7-6.4).

Conclusions:

The effectiveness and tolerability of palbociclib in real-world clinical practice corresponded well with the results obtained in the PALOMA-3 clinical trial. Despite the differences in dose modifications, this study suggests that there is no efficacy-effectiveness gap in this patient population.

GetReal in mathematical modelling: a review of studies predicting drug effectiveness in the real world

The performance of a drug in a clinical trial setting often does not reflect its effect in daily clinical practice. In this third of three reviews, we examine the applications that have been used in the literature to predict real‐world effectiveness from randomized controlled trial efficacy data. We searched MEDLINE, EMBASE from inception to March 2014, the Cochrane Methodology Register, and websites of key journals and organisations and reference lists. We extracted data on the type of model and predictions, data sources, validation and sensitivity analyses, disease area and software. We identified 12 articles in which four approaches were used: multi‐state models, discrete event simulation models, physiology‐based models and survival and generalized linear models. Studies predicted outcomes over longer time periods in different patient populations, including patients with lower levels of adherence or persistence to treatment or examined doses not tested in trials. Eight studies included individual patient data. Seven examined cardiovascular and metabolic diseases and three neurological conditions. Most studies included sensitivity analyses, but external validation was performed in only three studies. We conclude that mathematical modelling to predict real‐world effectiveness of drug interventions is not widely used at present and not well validated. © 2016 The Authors Research Synthesis Methods Published by John Wiley & Sons Ltd.

The "Efficacy-Effectiveness Gap": Historical Background and Current Conceptualization

BACKGROUND

The concept of the "efficacy-effectiveness gap" (EEG) has started to challenge confidence in decisions made for drugs when based on randomized controlled trials alone. Launched by the Innovative Medicines Initiative, the GetReal project aims to improve understanding of how to reconcile evidence to support efficacy and effectiveness and at proposing operational solutions.

OBJECTIVES

The objectives of the present narrative review were 1) to understand the historical background in which the concept of the EEG has emerged and 2) to describe the conceptualization of EEG.

METHODS

A focused literature review was conducted across the gray literature and articles published in English reporting insights on the EEG concept. The identification of different "paradigms" was performed by simple inductive analysis of the documents' content.

RESULTS

The literature on the EEG falls into three major paradigms, in which EEG is related to 1) real-life characteristics of the health care system; 2) the method used to measure the drug's effect; and 3) a complex interaction between the drug's biological effect and contextual factors.

CONCLUSIONS

The third paradigm provides an opportunity to look beyond any dichotomy between "standardized" versus "real-life" characteristics of the health care system and study designs. Namely, future research will determine whether the identification of these contextual factors can help to best design randomized controlled trials that provide better estimates of drugs' effectiveness.