FABry Disease Patient-Reported Outcome-GastroIntestinal (FABPRO-GI): A new Fabry disease-specific gastrointestinal outcomes instrument.

PURPOSE: Fabry disease is a rare multisystemic disorder caused by functional deficiency of the lysosomal enzyme alpha-galactosidase A. Gastrointestinal (GI) signs and symptoms are among the earliest clinical manifestations in patients with Fabry disease but are often nonspecific, misdiagnosed, and untreated. No instruments have been developed specifically to assess GI signs and symptoms in Fabry disease. The FABry disease Patient-Reported Outcome-GastroIntestinal (FABPRO-GI) was developed to address this unmet need and is intended for use in clinical trials (24-h FABPRO-GI) and real-world settings (7-day FABPRO-GI). METHODS: Findings from a literature review, expert advisory meetings, and patient concept elicitation interviews (CEIs) were summarized into conceptual models. These conceptual models were used to develop preliminary versions of the 24-h and 7-day FABPRO-GI. Cognitive debriefing interviews (CDIs) were conducted with additional patients to assess content validity, including understandability, relevance, and comprehensiveness of the preliminary versions of the 24-h and 7-day FABPRO-GI. RESULTS: Literature review (n = 17 articles), expert advisory meetings (n = 5), and patient CEIs (n = 17) identified mostly overlapping Fabry disease-related GI signs and symptoms, including abdominal cramps, bloating, and diarrhea, and informed development of the preliminary 24-h and 7-day FABPRO-GI. CDIs (n = 15) provided evidence of content validity and informed revisions of the 24-h and 7-day FABPRO-GI. CONCLUSION: With evidence of content validity, the 24-h and 7-day FABPRO-GI are the first Fabry disease-specific patient-reported outcomes to assess GI signs and symptoms in patients with Fabry disease with potential for use in clinical trials and real-world settings, respectively.

Comparison of the EMA and FDA Guidelines on Ulcerative Colitis Drug Development.

BACKGROUND & AIMS: In 2016, the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) released revised EMA and new FDA draft guidelines related to the development of drugs intended for the treatment of ulcerative colitis. We sought to compare and contrast the EMA draft guideline with the FDA draft guidance to facilitate further discussion and perhaps harmonization between the 2 guidelines when they are finalized. METHODS: A concordance document was created by arranging like or similar topics addressed by the guidelines side by side in a tabular format. This concordance table served as a source for writing the narrative. The first draft was subjected to repeated rounds of reviews and revisions by the authors and outside reviewers, all of them familiar with the subject matter from a regulatory science and/or academic perspective. RESULTS: The FDA guidance focuses on end points, whereas the EMA guideline additionally supplies much useful information for trial design. FDA guidance appears more aspirational, suggesting the development of entirely new patient-reported outcome instruments and the incorporation of a not-yet-validated histology instrument into the definition of mucosal healing. CONCLUSIONS: The guidelines by the FDA and the EMA complement each other and together are aimed to further practical drug development toward more clinically relevant end points in ulcerative colitis. Efforts are needed to harmonize the documents.

Global Harmonization of Pediatric Drug Development: Critical for Progress for Developing Safe and Effective Therapeutic Agents for Children.

The article, "Questionable Industry-Sponsored Studies in Children and Adolescents in Slovenia" provides an opportunity to discuss evolving US and EU legislative measures to improve the available clinical trial-derived pediatric data and provide coherent labeling for pediatric providers in dosing of drugs for children.

Pediatric Crohn Disease Clinical Outcome Assessments and Biomarkers: Current State and Path Forward for Global Collaboration.

OBJECTIVE: There is a pressing need for drug development in pediatric Crohn disease (CD). Our aim was to provide strategic approaches toward harmonization of current thinking about clinical outcome assessments (COAs) and biomarkers to facilitate drug development in pediatric CD. METHODS: Scientists from the United States Food and Drug Administration, European Medicines Agency, Health Canada, and the Pharmaceuticals and Medical Devices Agency of Japan had monthly teleconferences from January 2014 through May 2015. A literature review was conducted to assess the measurement properties of all existing COA tools and to evaluate the current landscape of biomarkers used in pediatric CD. Based on the findings of literature review, we reached the consensus on the strategic approaches for evaluating outcomes in pediatric CD trials. RESULTS: The pediatric Crohn's Disease Activity Index, Crohn's Disease Activity Index, and Harvey-Bradshaw's index were used in pediatric CD clinical studies. But they lack adequate measurement properties (validity, reliability, and ability to detect change of the treatment) that are required to support approval of products intended to treat pediatric CD. Biomarkers (ie, fecal lactoferrin, osteoprotegerin, and calprotectin) have shown some promise for their potential as noninvasive surrogate endpoints in CD. CONCLUSIONS: Lack of well-defined and reliable COAs presents a hurdle for global drug development in pediatric CD. It is essential to develop well-defined and reliable COAs that can measure meaningful clinical benefit for patients in terms of how they feel, function, and survive. Development of noninvasive biomarkers as reliable surrogate endpoints needs to be further explored.

Esomeprazole FDA Approval in Children With GERD: Exposure-Matching and Exposure-Response.

OBJECTIVES: Food and Drug Administration approval of proton-pump inhibitors for infantile gastroesophageal reflux disease has been limited by intrapatient variability in the clinical assessment of gastroesophageal reflux disease. For children 1 to 17 years old, extrapolating efficacy from adults for IV esomeprazole was accepted. The oral formulation was previously approved in children. Exposure-response and exposure matching analyses were sought to identify approvable pediatric doses. METHODS: Intragastric pH biomarker comparisons between children and adults were conducted. Pediatric doses were selected to match exposures in adults and were based on population pharmacokinetic (PK) modeling and simulations with pediatric esomeprazole data. Observed IV or oral esomeprazole PK data were available from 50 and 117 children, between birth and 17 years, respectively, and from 65 adults, between 20 and 48 years. A population PK model developed using these data was used to simulate steady-state esomeprazole exposures for children at different doses to match the observed exposures in adults. RESULTS: Exposure-response relationships of intragastric pH measures were similar between children and adults. The PK simulations identified a dosing regimen for children that results in comparable steady-state area under the curve to that observed after 20 mg in adults. For IV esomeprazole, increasing the infusion duration to 10 to 30 minutes in children achieves matching Cmax values with adults. CONCLUSIONS: The exposure-matching analysis permitted approval of an esomeprazole regimen not studied directly in clinical trials. Exposure-response for intragastric pH-permitted approval for the treatment of gastroesophageal reflux disease in children in whom it was not possible to evaluate the adult primary endpoint, mucosal healing assessed by endoscopy.

Neurocognitive clinical outcome assessments for inborn errors of metabolism and other rare conditions.

Well-defined and reliable clinical outcome assessments are essential for determining whether a drug provides clinically meaningful treatment benefit for patients. In 2015, FDA convened a workshop, "Assessing Neurocognitive Outcomes in Inborn Errors of Metabolism." Topics covered included special challenges of clinical studies of inborn errors of metabolism (IEMs) and other rare diseases; complexities of identifying treatment effects in the context of the dynamic processes of child development and disease progression; and the importance of natural history studies. Clinicians, parents/caregivers, and participants from industry, academia, and government discussed factors to consider when developing measures to assess treatment outcomes, as well as tools and methods that may contribute to standardizing measures. Many issues examined are relevant to the broader field of rare diseases in addition to specifics of IEMs.

Nutritional interventions in primary mitochondrial disorders: Developing an evidence base.

In December 2014, a workshop entitled "Nutritional Interventions in Primary Mitochondrial Disorders: Developing an Evidence Base" was convened at the NIH with the goals of exploring the use of nutritional interventions in primary mitochondrial disorders (PMD) and identifying knowledge gaps regarding their safety and efficacy; identifying research opportunities; and forging collaborations among researchers, clinicians, patient advocacy groups, and federal partners. Sponsors included the NIH, the Wellcome Trust, and the United Mitochondrial Diseases Foundation. Dietary supplements have historically been used in the management of PMD due to their potential benefits and perceived low risk, even though little evidence exists regarding their effectiveness. PMD are rare and clinically, phenotypically, and genetically heterogeneous. Thus patient recruitment for randomized controlled trials (RCTs) has proven to be challenging. Only a few RCTs examining dietary supplements, singly or in combination with other vitamins and cofactors, are reported in the literature. Regulatory issues pertaining to the use of dietary supplements as treatment modalities further complicate the research and patient access landscape. As a preface to exploring a research agenda, the workshop included presentations and discussions on what PMD are; how nutritional interventions are used in PMD; challenges and barriers to their use; new technologies and approaches to diagnosis and treatment; research opportunities and resources; and perspectives from patient advocacy, industry, and professional organizations. Seven key areas were identified during the workshop. These areas were: 1) defining the disease, 2) clinical trial design, 3) biomarker selection, 4) mechanistic approaches, 5) challenges in using dietary supplements, 6) standards of clinical care, and 7) collaboration issues. Short- and long-term goals within each of these areas were identified. An example of an overarching goal is the enrollment of all individuals with PMD in a natural history study and a patient registry to enhance research capability. The workshop demonstrates an effective model for fostering and enhancing collaborations among NIH and basic research, clinical, patient, pharmaceutical industry, and regulatory stakeholders in the mitochondrial disease community to address research challenges on the use of dietary supplements in PMD.

Exposure-Response of Palonosetron for Prevention of Chemotherapy-Induced Nausea and Vomiting in Pediatric Patients.

OBJECTIVES: Extrapolation of efficacy from adult populations to pediatrics may be appropriate if it is reasonable to assume that the 2 populations have similar disease progression and response to intervention. When full extrapolation of efficacy is deemed appropriate, the pediatric dose can be determined by "matching" exposure to a drug with that observed in adult patients. This approach has been used in certain therapeutic areas to alleviate the burden of pediatric clinical trials. We present here a case in which exposure matching is not appropriate. METHODS: Data analyses including pharmacokinetics and exposure-response were performed using data obtained from 2 pediatric chemotherapy-induced nausea and vomiting trials for intravenously administered palonosetron (Aloxi; a 5-HT3 receptor antagonist) injection and the results were compared with adult findings. RESULTS: At the approved doses for adults (0.25 mg) and pediatric patients (20 µg/kg), mean systemic exposure (area under the curve) of palonosetron in pediatric patients was approximately 3-fold higher than that in adults, whereas the response rate was similar between the 2 populations. Across pediatric patients, those younger than 6 years of age appeared to have a higher response than those ages 6 years or older, even though estimated systemic exposure was comparable between these age groups. CONCLUSIONS: Overall, these analyses provide an example in which pediatric and adult exposure data alone are insufficient to adequately identify effective pediatric doses and raise questions about the appropriateness of exposure matching for other drugs in the same therapeutic class. In such cases, pediatric dose-ranging and efficacy studies are needed.

Well-defined and reliable clinical outcome assessments for pediatric Crohn disease: a critical need for drug development.

OBJECTIVES: The aim of the present study was to identify areas for further development of clinical outcome assessment (COA) in pediatric Crohn disease (CD). METHODS: The study analyzed the measurement properties of all existing COA tools for pediatric CD in literature and published registration trials of approved drugs for pediatric CD based on criteria described in Food and Drug Administration guidance for patient-reported outcome (PRO) development. RESULTS: The Pediatric Crohn's Disease Activity Index (PCDAI) and its derivatives (abbreviated, short, modified, and weighted PCDAIs) were reviewed. The Crohn's Disease Activity Index (CDAI) and Harvey-Bradshaw index (HBI), designed for adult patients, have been adapted for use in a few pediatric CD studies. The use of PCDAI as an endpoint in Remicade and Humira trials led to the Food and Drug Administration-approved indication in pediatric CD. Common issues in measurement properties of COA tools included the absence of direct patient or caregivers' input to generate the items measuring signs and symptoms; absence of evidence demonstrating correlation with clinically relevant inflammation observed with endoscopic measures; lack of standardization in measurement, age-appropriate interviewer script, and response rating criteria for the physician interviewer. CONCLUSIONS: Available evidence indicates that CDAI, HBI, and 5 versions of the PCDAI lack adequate measurement properties for use as a primary endpoint for phase 3 trials intended to support approval of products intended to treat pediatric CD. In order to facilitate pediatric drug development, a well-defined, reliable, sensitive, and globally recognized PRO that measures signs and symptoms in children with CD and that can be used in conjunction with endoscopy-based endpoints and/or biomarkers is sorely needed.

Phenylketonuria Scientific Review Conference: state of the science and future research needs.

New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 µmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 µmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.

Alternate endpoints and clinical outcome assessments in pediatric ulcerative colitis registration trials.

OBJECTIVES: Presently, there is no consensus on endpoint measures to assess clinical outcomes for pediatric ulcerative colitis (UC). This study reviewed the endpoints used in the registration trials of approved drugs for pediatric UC. METHODS: The primary efficacy endpoints of all registration trials completed from 1950 to 2008 that led to Food and Drug Administration approval for indications in pediatric and adult UC were reviewed. RESULTS: Colazal and Remicade have been approved for pediatric UC indication, and clinical response was used as a primary endpoint in these registration trials. The clinical response in the adult Colazal trials was defined as a reduction of rectal bleeding and improvement in at least one of the other assessed symptoms (stool frequency, patient functional assessment, abdominal pain, sigmoidoscopic grade, and physician's global assessment) assessed by the Sutherland UC Activity Index. The pediatric Colazal trial defined clinical response using the Modified Sutherland UC Activity Index, which excluded abdominal pain and functional assessment. Both adult and pediatric Remicade trials used clinical response defined by the Mayo score as the primary endpoint. The Pediatric Ulcerative Colitis Activity Index was used to measure various secondary endpoints in the pediatric Remicade trial. CONCLUSIONS: Pediatric-specific endpoints were used, but outcome measures and definition of clinical response were not consistent in pediatric UC trials. Consensus on the definition of successful treatment outcome (clinical response and/or remission) and collaboration in the development of well-defined and reliable measures of signs and symptoms for use in conjunction with endoscopic parameters of mucosal healing will facilitate pediatric drug development.

Steps toward harmonization for clinical development of medicines in pediatric ulcerative colitis-a global scientific discussion, part 1: efficacy endpoints and disease outcome assessments.

OBJECTIVES: There is a pressing need for drug development in pediatric ulcerative colitis (UC). Lack of scientific consensus on efficacy endpoints and disease outcome assessments presents a hurdle for global drug development in pediatric UC. Scientists from 4 regulatory agencies convened an International Inflammatory Bowel Disease Working Group (i-IBD Working Group) to harmonize present thinking about various aspects of drug development in pediatric UC globally. METHODS: The i-IBD Working Group was convened in 2012 by scientists from the US Food and Drug Administration, European Medicines Agency, Health Canada, and the Pharmaceuticals and Medical Devices Agency of Japan. The members of this group considered reasons for differences in their acceptance of efficacy endpoints and disease activity indices used in pediatric UC, reviewed the available literature, and developed consensus opinions regarding approaches for evaluating outcomes in pediatric UC trials. RESULTS: There is lack of harmonization in using efficacy endpoint and outcome assessments including disease activity indices to assess clinical benefit in pediatric UC trials. Many disease activity indices have been developed, but their biometric properties, such as responsiveness, reliability, and validity, have not been properly validated. Biomarkers, such as fecal calprotectin and lactoferrin, are being investigated for their potential as noninvasive surrogate endpoints in UC. CONCLUSIONS: Consensus on the efficacy endpoints, disease activity indices, and outcome assessments is needed for globalization of pediatric UC trials. The i-IBD Working Group offers several perspectives to facilitate harmonization across regions. The development of noninvasive biomarkers as reliable surrogate endpoints needs to be explored further.

Steps toward harmonization for clinical development of medicines in pediatric ulcerative colitis-a global scientific discussion, part 2: data extrapolation, trial design, and pharmacokinetics.

OBJECTIVES: To facilitate global drug development, the International Pediatric Inflammatory Bowel Disease Working Group (i-IBD Working Group) discussed data extrapolation, trial design, and pharmacokinetic (PK) considerations for drugs intended to treat pediatric ulcerative colitis (UC), and considered possible approaches toward harmonized drug development. METHODS: Representatives from the US Food and Drug Administration, European Medicines Agency, Health Canada, and the Pharmaceuticals and Medical Devices Agency of Japan convened monthly to explore existing regulatory approaches, reviewed the results of a literature search, and provided perspectives on pediatric UC drug development based on the available medical literature. RESULTS: Although pediatric UC, when compared with UC in adults, has a similar disease progression and response to intervention, the similarity of the exposure-response relation has not been adequately established. Consequently, clinical endpoints should be selected to optimally assess efficacy in children. The inclusion of a placebo control in pediatric trials to assure assay sensitivity may be appropriate under limited circumstances. In clinical studies, although the drug under investigation could provide possible direct benefit, placebo treatment should present no more than a minor increase over minimal risk to children with UC. CONCLUSIONS: Partial extrapolation of efficacy from informative adult studies may be appropriate. Placebo-controlled efficacy trials are scientifically and ethically appropriate for pediatric UC given appropriate patient selection and the use of early escape. Clinical studies in pediatric UC may include initial dose-finding studies and exposure-response modeling followed by an efficacy and safety study to further explore the exposure-response relation.

Expanding research to provide an evidence base for nutritional interventions for the management of inborn errors of metabolism.

A trans-National Institutes of Health initiative, Nutrition and Dietary Supplement Interventions for Inborn Errors of Metabolism (NDSI-IEM), was launched in 2010 to identify gaps in knowledge regarding the safety and utility of nutritional interventions for the management of inborn errors of metabolism (IEM) that need to be filled with evidence-based research. IEM include inherited biochemical disorders in which specific enzyme defects interfere with the normal metabolism of exogenous (dietary) or endogenous protein, carbohydrate, or fat. For some of these IEM, effective management depends primarily on nutritional interventions. Further research is needed to demonstrate the impact of nutritional interventions on individual health outcomes and on the psychosocial issues identified by patients and their families. A series of meetings and discussions were convened to explore the current United States' funding and regulatory infrastructure and the challenges to the conduct of research for nutritional interventions for the management of IEM. Although the research and regulatory infrastructure are well-established, a collaborative pathway that includes the professional and advocacy rare disease community and federal regulatory and research agencies will be needed to overcome current barriers.

Off-label use of medicine in pediatrics: focus on gastrointestinal diseases.

PURPOSE OF REVIEW: To provide current information on off-label medication use in pediatric gastroenterology, including a discussion on US legislative efforts to address the issue. RECENT FINDINGS: Medications used to treat pediatric gastrointestinal illnesses are frequently prescribed off-label. Acid suppressors, antiemetics, laxatives, and antitumor necrosis factor therapies are types of medications frequently used off-label in the pediatric gastroenterology arena. Pediatric studies conducted under US Federal laws are generating much-needed data on the safety and effectiveness of medications used to treat pediatric patients. Moreover, a new US law, the Food and Drug Administration Safety and Innovation Act, may further the development of pediatric medications in part by requiring pediatric-specific study plans earlier in the overall drug development process. As of today, there still are gaps in our knowledge about these medications, including for the treatment of pediatric gastroenterology diseases. SUMMARY: Medications are widely used off-label in pediatrics, including medications intended to treat gastrointestinal diseases, such as antitumor necrosis factor and laxatives. Although legislation is helping to generate and make available important information about pediatric medications, most still do not contain pediatric data. Therefore, providers need to understand the potential risks and benefits of prescribing off-label products to pediatric patients.

Cross-sector sponsorship of research in eosinophilic esophagitis: a collaborative model for rational drug development in rare diseases.

Like many rare diseases, eosinophilic esophagitis (EoE) is a poorly understood disorder, and assessment tools to accurately determine disease activity, remission, and natural history have long been inadequate. Clinical outcome end points able to assess the effectiveness of candidate therapeutic agents in clinical trials have been a particular deficiency and are urgently needed. With no approved therapy available to patients and with the prevalence of EoE on the increase, collaborative approaches to drug development are becoming ever more important. We describe a collaborative effort mobilized across institutions, including both the public and private sectors, that was initiated within the past 18 months expressly to address the need for further clinical research into the cause and treatment of EoE. Collaborators include the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition; the International Gastrointestinal Eosinophilic Researchers; and the US Food and Drug Administration. This effort has resulted in the elucidation of several parameters essential for effective EoE registration trials, including the need for clinically meaningful end points that measure changes in clinical symptoms in addition to the assessment of intraepithelial mucosal eosinophilia. The development and use of biomarkers, particularly in early-phase drug development, have become an important focus for investigations that might reduce clinical reliance on serial invasive monitoring. The concerted efforts described here to develop rational therapeutics and drug development paradigms in EoE also appear to provide a model for effective collaboration in the context of drug development for rare diseases and perhaps more generally for public health initiatives.