Achieving big with small: quantitative clinical pharmacology tools for drug development in pediatric rare diseases.

Pediatric populations represent a major fraction of rare diseases and compound the intrinsic challenges of pediatric drug development and drug development for rare diseases. The intertwined complexities of pediatric and rare disease populations impose unique challenges to clinical pharmacologists and require integration of novel clinical pharmacology and quantitative tools to overcome multiple hurdles during the discovery and development of new therapies. Drug development strategies for pediatric rare diseases continue to evolve to meet the inherent challenges and produce new medicines. Advances in quantitative clinical pharmacology research have been a key component in advancing pediatric rare disease research to accelerate drug development and inform regulatory decisions. This article will discuss the evolution of the regulatory landscape in pediatric rare diseases, the challenges encountered during the design of rare disease drug development programs and will highlight the use of innovative tools and potential solutions for future development programs.

A Comparison of Pediatric and Adult Safety Studies for Antipsychotic and Antidepressant Drugs Submitted to the United States Food and Drug Administration.

OBJECTIVE: To examine the differences in the adverse drug reaction (ADR) profile of antipsychotic and antidepressant agents between pediatric and adult patients in studies submitted to the Food and Drug Administration (FDA) during the drug development process. STUDY DESIGN: Clinical trials in adult and pediatric patients were conducted by sponsors as part of the drug development programs for antipsychotic and antidepressant agents, and ADR information was collected as part of those trials and submitted to the FDA. Data collection was conducted by reviewing publicly available FDA-authored reviews and FDA-approved product labels for 10 drugs with an antipsychotic or an antidepressant indication from 2007 to 2017. RESULTS: There were 308 drug and ADR combinations for the 10 drugs and drug combinations with 113 (36.7%) having a significantly different incidence in pediatric patients compared with adults. Sixty-eight (60.2%) of these ADRs had a significantly higher incidence in pediatric patients than in adults. Sedation was higher in 6 of the 10 drugs and drug combinations with risk differences ranging from 9.6 to 36.6%. CONCLUSIONS: This analysis indicates that there were significant differences between the pediatric and adult safety profiles of antipsychotic and antidepressant drugs. Sedation was the major ADR associated with the use of atypical antipsychotic drugs in pediatric patients. Clinicians caring for children should consider the ADR profile when prescribing antipsychotics and antidepressants in pediatric patients.

Maternal-Fetal Drug Development: An Industry Perspective.

Medicines and vaccines prescribed to pregnant women often have not had pregnant women or lactating women included in clinical trials and products are often not approved by regulatory agencies for use in pregnant women. As a result, practitioners may need to prescribe medicines and give vaccines to this special population with limited drug efficacy and safety information available. Multiple regulatory guidance documents regarding the development of medications for pregnant and lactating women have been developed to encourage drug development and the investigation of medicines and vaccines used in this population. However, clinical, regulatory, ethical, and drug development challenges are encountered when designing clinical trials that include pregnant women and their fetuses, in which innovative methods and trial designs are essential. This article provides an overview of an industry perspective on maternal-fetal drug development that includes a review of the regulatory landscape for developing medicines for pregnant women and their fetuses, trial designs that include pregnant women, identification of gaps and challenges, and strategies for potential maternal-fetal drug development considerations for the future development of medicines and vaccines for pregnant women. Early involvement and discussion of drug and vaccine products with multiple stakeholders, including therapeutic experts, patients, physicians, and regulators, is encouraged to optimize the development of safe and effective medicines and vaccines for pregnant women and their fetuses.

Hypothalamic-Pituitary-Adrenal Axis Pediatric Safety Studies Submitted to the FDA.

BACKGROUND: Corticosteroid use has been associated with hypothalamic-pituitary-adrenal (HPA) axis suppression which can predispose the pediatric patient to multiple immune- and growth-related adverse effects. The objectives of this review were to identify the pediatric drug development programs involving corticosteroids and the associated pediatric HPA axis suppression studies submitted to the US Food and Drug Administration (FDA), capture FDA guidance topic related recommendations, and determine the consistency of HPA axis data in prescription corticosteroid labeling. METHODS: A review of FDA submissions from January 2002 to July 2018 involving corticosteroid products and HPA axis testing in pediatric patients was conducted. The adrenal function testing methods, number of pediatric HPA axis dedicated studies, duration of these studies, and the labeling outcomes were assessed. RESULTS: Of the 437 total drug products that were submitted to FDA, only 36 products were corticosteroids or a corticosteroid combination product yielding a total of 83 pediatric clinical studies. Twenty-four of the 36 products included 37 HPA axis suppression dedicated studies which employed different measurement methods. The pediatric HPA axis suppression trial data collected did not necessitate any new actionable recommendations in the FDA labeling. CONCLUSION: Future pediatric drug development program goals would be to determine whether HPA axis suppression studies should be conducted, establish optimal testing methods if HPA axis testing is performed, continue to update guidances for industry, and actionable labeling recommendations. However, regulatory policy related to conducting pediatric HPA axis studies requires additional scientific research and discussion by the pediatric drug development community.

Combined Pediatric and Adult Trials Submitted to the US Food and Drug Administration 2012-2018.

Despite legislation incentivizing and requiring drug companies to conduct pediatric clinical trials, there still is a 9-year delay in drug approval for pediatric labeling after the initial adult drug approval. The aim of this study was to review the experience of the US Food and Drug Administration (FDA) with combined pediatric and adult trials as a means for expediting pediatric approval and labeling. Combined pediatric and adult trials submitted to the FDA from 2012 to 2018 were reviewed. Only the publicly available labels and reviews were utilized for this analysis. Combined trials were identified for 72 products, with a total of 156 combined adult and pediatric trials. The therapeutic areas with the largest number of combined trials were in pulmonology for products reviewed under the Best Pharmaceuticals for Children Act (BPCA) and/or the Pediatric Research Equity Act (PREA), and hematology reviewed under the Orphan Drug Act (ODA). All drugs that utilized combined pediatric and adult clinical trials were approved simultaneously for both the adults and that part of the pediatric population. A separate pediatric subgroup efficacy analysis was reported in 57% and 48% of products under BPCA/PREA and the ODA, respectively, with a separate safety analysis in 48% and 38% of these products. When considering both BPCA/PREA and orphan drug studies, all the combined pediatric and adult trials allowed concurrent approval and labeling for part of the pediatric population at the time of the adult approval.

Surrogate Endpoints in Pediatric Studies Submitted to the US FDA.

The 21st Century Cures Act was passed in December, 2016, and included a number of provisions to facilitate drug approval. Considerable discussion was generated related to some aspects of the Act, especially to the use of surrogate endpoints (SEs) as a means to shorten the time required prior to receiving US Food and Drug Administration (FDA) approval.1 The objective of this analysis was to identify the use and outcomes of SEs and clinical endpoints in pediatric drug development trials.

Monoclonal Antibodies and Fc-Fusion Proteins for Pediatric Use: Dosing, Immunogenicity, and Modeling and Simulation in Data Submitted to the US Food and Drug Administration.

The experience with the use of monoclonal antibodies and Fc-fusion proteins (mAb/Fc) in the pediatric population is limited. The objective of this study is to review those factors impacting the clinical efficacy and product safety of mAb/Fc products in pediatric patients during drug development. We reviewed the list of biologic products in the US Food and Drug Administration's Purple Book as of March 2018 with a focus on mAb/Fc products that are indicated for use in both adults and pediatric patients. Of 68 mAb/Fc products in the Purple Book (excluding biosimilars), 20 products have approved indications in both adults and children. Thirteen products had concurrent approval for both adult and pediatric populations. The sample size of pediatric studies generally ranged from approximately 2% to 70% of the sample size of adult studies with the same indication. In general, pediatric dosing regimens were found to be more based on body weight and weight tiered than the regimens for adults. Modeling and simulation techniques comprised mainly population pharmacokinetic and pharmacodynamic models. A review of the immunogenicity incidence did not reveal any notable difference in the 5 products having data on both pediatric and adult patients. In conclusion, most of the mAb/Fc products have a different weight-based dosing regimen for pediatric patients versus adults. An understanding of the comparative experience in drug development for mAb/Fc products between adult and pediatric patients coupled with the application of advanced modeling and simulation methods should assist future development of new mAb/Fc products for pediatric patients.

Primary Endpoints in Pediatric Efficacy Trials Submitted to the US FDA.

The selection of appropriate endpoints in pediatric drug development trials is a critical aspect of trial design. Given the high pediatric trial failure rate, selecting optimal trial design elements, such as the primary efficacy endpoint, is essential to ensuring increased potential for trial success. The objectives of this study were to identify the primary efficacy endpoints measured in pediatric drug development trials submitted to the US Food and Drug Administration and to relate endpoint attributes to trial and label outcome. The analysis included pediatric pivotal efficacy studies submitted from September 2007 to July 2016 for which there was a corresponding adult trial for the same indication. Two hundred and thirty-four efficacy trials on 138 unique products studied in pediatric patients were assessed. The adult and pediatric endpoints were the same in 141 of the 234 trials (60.3%), and these trials succeeded in meeting their primary endpoint more often (122 of 141 [86.5%]) than when the adult and pediatric endpoints differed (57 of 93 [61.3%]; odds ratio, 4.03; 95%CI, 2.10-7.80). Trials that included both pediatric and adult patients succeeded more frequently than those trials that did not combine pediatric and adult patients (85 of 95 versus 94 of 139, respectively; odds ratio, 4.05; 95%CI, 1.94-9.31). No differences were observed in pediatric trial success between those using subjective and objective endpoints. Using the same endpoint in the pediatric trial as was measured in the corresponding adult trial and enrolling pediatric and adult patients in the same trial were attributes associated with trial success.

Enrichment Strategies in Pediatric Drug Development: An Analysis of Trials Submitted to the US Food and Drug Administration.

Clinical trial enrichment involves prospectively incorporating trial design elements that increase the probability of detecting a treatment effect. The use of enrichment strategies in pediatric drug development has not been systematically assessed. We analyzed the use of enrichment strategies in pediatric trials submitted to the US Food and Drug Administration from 2012-2016. In all, 112 efficacy studies associated with 76 drug development programs were assessed and their overall success rates were 78% and 75%, respectively. Eighty-eight trials (76.8%) employed at least one enrichment strategy; of these, 66.3% employed multiple enrichment strategies. The highest trial success rates were achieved when all three enrichment strategies (practical, predictive, and prognostic) were used together within a single trial (87.5%), while the lowest success rate was observed when no enrichment strategy was used (65.4%). The use of enrichment strategies in pediatric trials was found to be associated with trial and program success in our analysis.