A comparison of interventional clinical trials in rare versus non-rare diseases: an analysis of ClinicalTrials.gov

Clinical trial evidence supporting FDA approval of novel orphan drugs between 2017 and 2023

Characterization analysis of 87 pivotal clinical trials for 72 novel orphan drugs (76 orphan indications) approved by the FDA from 2017 to 2023 revealed that the clinical trial evidence supporting FDA orphan drug approvals often lacked high-quality designs, which frequently did not incorporate randomization, blinding, placebo or no treatment control, or clinical endpoint-driven methodologies. Additionally, regulatory flexibility was observed in the quantity of clinical trial evidence required, which included choices such as a single trial plus confirmatory evidence, one large multicenter trial or at least two trials. Furthermore, the overall strength of the clinical trial evidence exhibited variations across different orphan drugs and indications, influenced by features such as the therapeutic area and whether the orphan drug was granted accelerated approvals.

Systematic Review of Genetic Substrate Reduction Therapy in Lysosomal Storage Diseases: Opportunities, Challenges and Delivery Systems

BACKGROUND

Genetic substrate reduction therapy (gSRT), which involves the use of nucleic acids to downregulate the genes involved in the biosynthesis of storage substances, has been investigated in the treatment of lysosomal storage diseases (LSDs).

OBJECTIVE

To analyze the application of gSRT to the treatment of LSDs, identifying the silencing tools and delivery systems used, and the main challenges for its development and clinical translation, highlighting the contribution of nanotechnology to overcome them.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines was performed. PubMed, Scopus, and Web of Science databases were used for searching terms related to LSDs and gene-silencing strategies and tools.

RESULTS

Fabry, Gaucher, and Pompe diseases and mucopolysaccharidoses I and III are the only LSDs for which gSRT has been studied, siRNA and lipid nanoparticles being the silencing strategy and the delivery system most frequently employed, respectively. Only in one recently published study was CRISPR/Cas9 applied to treat Fabry disease. Specific tissue targeting, availability of relevant cell and animal LSD models, and the rare disease condition are the main challenges with gSRT for the treatment of these diseases. Out of the 11 studies identified, only two gSRT studies were evaluated in animal models.

CONCLUSIONS

Nucleic acid therapies are expanding the clinical tools and therapies currently available for LSDs. Recent advances in CRISPR/Cas9 technology and the growing impact of nanotechnology are expected to boost the clinical translation of gSRT in the near future, and not only for LSDs.

Assessing Post-Marketing Requirements for Orphan Drugs: A Cross-Sectional Analysis of FDA and EMA Oversight

The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) oversee pharmaceutical regulations, including orphan drugs targeting rare diseases with limited patient populations. Post-marketing studies are crucial for monitoring safety and efficacy, with post-marketing requirements (PMRs) mandated by the regulatory agencies to ensure compliance. This study aims to compare PMR statuses, objectives, and pivotal trial characteristics of orphan drugs approved by the FDA (n = 154) and EMA (n = 79) from 2008 to 2018, shedding light on regulatory differences and their impact on drug development. Contrary to expectations, our analysis found no significant disparity in the proportion of orphan drugs with and without PMRs approved by both the FDA (48.1%) and EMA (55.7%). Safety concerns surrounding orphan drugs post-approval, attributed partly to pivotal trial design, underscore the need for robust post-marketing surveillance. While the FDA primarily focuses on post-marketing safety (36.1%), the EMA places a higher emphasis on both efficacy and safety (47.1%), reflecting distinct approaches to PMR management between the two regulatory bodies. The observed trend of delayed PMRs at the EMA (47.1%) highlights the importance of effective cooperation between regulators and pharmaceutical companies to ensure the timely completion of PMRs and enhance drug safety.

Special FDA designations for drug development: orphan, fast track, accelerated approval, priority review, and breakthrough therapy

BACKGROUND

Over the past decades, US Congress enabled the US Food and Drug Administration (FDA) to facilitate and expedite drug development for serious conditions filling unmet medical needs with five special designations and review pathways: orphan, fast track, accelerated approval, priority review, and breakthrough therapy.

OBJECTIVES

This study reviews the FDA's five special designations for drug development regarding their safety, efficacy/clinical benefit, clinical trials, innovation, economic incentives, development timelines, and price.

METHODS

We conducted a keyword search to identify studies analyzing the impact of the FDA's special designations (orphan, fast track, accelerated approval, priority review, and breakthrough therapy) on the safety, efficacy/clinical benefit, trials, innovativeness, economic incentives, development times, and pricing of new drugs. Results were summarized in a narrative overview.

RESULTS

Expedited approval reduces new drugs' time to market. However, faster drug development and regulatory review are associated with more unrecognized adverse events and post-marketing safety revisions. Clinical trials supporting special FDA approvals frequently use small, non-randomized, open-label designs. Required post-approval trials to monitor unknown adverse events are often delayed or not even initiated. Evidence suggests that drugs approved under special review pathways, marketed as "breakthroughs", are more innovative and deliver a higher clinical benefit than those receiving standard FDA approval. Special designations are an economically viable strategy for investors and pharmaceutical companies to develop drugs for rare diseases with unmet medical needs, due to financial incentives, expedited development timelines, higher clinical trial success rates, alongside greater prices. Nonetheless, patients, physicians, and insurers are concerned about spending money on drugs without a proven benefit or even on drugs that turn out to be ineffective. While European countries established performance- and financial-based managed entry agreements to account for this uncertainty in clinical trial evidence and cost-effectiveness, the pricing and reimbursement of these drugs remain largely unregulated in the US.

CONCLUSION

Special FDA designations shorten clinical development and FDA approval times for new drugs treating rare and severe diseases with unmet medical needs. Special-designated drugs offer a greater clinical benefit to patients. However, physicians, patients, and insurers must be aware that special-designated drugs are often approved based on non-robust trials, associated with more unrecognized side effects, and sold for higher prices.

Rare disease clinical trials in the European Union: navigating regulatory and clinical challenges

BACKGROUND

Clinical development for orphan drugs presents significant difficulties and challenges. There is no unique or standard design, conduct, and outcome assessment methodology and it is sometimes impractical to fit design models of rare disease trials in any practiced and well-known framework. In the European Union (EU) these challenges encompass a broad array of subjects, including trial design, study outcomes, patient recruitment, trial conduct ethics, trial cost, and chances of success. This literature-based review study aims to provide a thorough overview of the critical aspects of rare disease trials in the EU by analyzing the current landscape of rare disease trials, highlighting key challenges, delving into regulatory and research initiatives and innovation in trial designs, and proposing multi-faceted solutions to implement effective rare disease clinical trials in the region.

DISCUSSION

Traditional clinical trial designs, validation, and evaluation methodologies used for nonorphan drugs often prove unsuitable for orphan drugs, given the small patient populations, sometimes fewer than 1000 cases. There is an increasing need for accessible therapies and both regulators as well as industry are trying to develop affordable and effective drugs to address this need. Despite several steps that have been taken, the timely development of drugs remains a challenge. One of the reasons behind the long development timeline is the recruitment, retention, and conduct of rare disease trials. To optimize the development timelines of orphan drugs in the EU, it is important to ensure that the safety and efficacy of the product is not compromised. Industry and regulatory agencies must implement innovative trial designs, devise flexible policies, and incorporate real-world data for assessing clinical outcomes.

CONCLUSION

Collaboration among academic institutions, pharmaceutical companies (both small and major), patient groups, and health authorities is crucial in overcoming obstacles related to clinical trials and providing assistance and creative ideas. The ultimate objective of granting rare disease patients timely and affordable access to medications with a positive balance between benefits and risks is to be met.

The quality of reporting in case reports of permanent neonatal diabetes mellitus: a cross-sectional study

BACKGROUND

Although randomized trials and systematic reviews provide the best evidence to guide medical practice, many permanent neonatal diabetes mellitus (PNDM) studies have been published as case reports. However, the quality of these studies has not been assessed. The purpose of this study was to assess the extent to which the current case reports for PNDM comply with the Case Report (CARE) guidelines and to explore variables associated with the reporting.

METHOD

Six English and four Chinese databases were searched from their inception to December 2022 for PNDM case reports. The 23 items CARE checklist was used to measure reporting quality. Primary outcome was the adherence rate of each CARE item and second outcome was total reporting score for each included PNDM case report. Linear and logistic regression analyses were used to examine the connection between five pre-specified predictor variables and the reporting quality. The predictor variables were impact factor of the published journal (<3.4 vs. ≥3.4, categorized according to the median), funding (yes vs. no), language (English vs. other language), published journal type (general vs. special) and year of publication (>2013 vs. ≤ 2013).

RESULT

In total, 105 PNDM case reports were included in this study. None of the 105 PNDM case reports fulfilled all 23 items of the CARE checklist. The response rate of 11 items were under 50%, including prognostic characteristics presentation (0%), patient perspective interpretation (0%), diagnostic challenges statement (2.9%), clinical course summary (21.0%), diagnostic reasoning statement (22.9%), title identification (24.8%), case presentation (33.3%), disease history description (34.3%), strengths and limitations explanation (41.0%), informed consent statement (45.7%), and lesson elucidation (47.6%). This study identified that the PNDM case reports published in higher impact factor journals were statistically associated with a higher reporting quality.

CONCLUSION

The reporting of case reports for PNDM is generally poor. As a result, this information may be misleading to providers, and the clinical applications may be detrimental to patient care. To improve reporting quality, journals should encourage strict adherence to the CARE guidelines.

Exploring regulatory flexibility to create novel incentives to optimize drug discovery

Efforts by governments, firms, and patients to deliver pioneering drugs for critical health needs face a challenge of diminishing efficiency in developing those medicines. While multi-sectoral collaborations involving firms, researchers, patients, and policymakers are widely recognized as crucial for countering this decline, existing incentives to engage in drug development predominantly target drug manufacturers and thereby do little to stimulate collaborative innovation. In this mini review, we consider the unexplored potential within pharmaceutical regulations to create novel incentives to encourage a diverse set of actors from the public and private spheres to engage in the kind of collaborative knowledge exchange requisite for fostering enhanced innovation in early drug development.

Clinical benefit, development, innovation, trials, epidemiology, and price for cancer drugs and indications with multiple special FDA designations

BACKGROUND

This study analyzes the development, US Food and Drug Administration (FDA) approval, benefits, innovation, trials, epidemiology, and price of cancer drugs with multiple special designations: orphan, fast track, accelerated approval, priority review, and breakthrough therapy.

METHODS

In total, 355 FDA-approved cancer drug indications with 841 special designations were identified (2012-2022). Trial, epidemiology, and price data were collected from FDA labels, the Global Burden of Disease study, and Medicare and Medicaid. The association between efficacy outcomes and indications' number of special designations were compared in meta-analyses.

RESULTS

Median development times were 7.3, 7.8, and 5.4 months (P = .027) for drugs with 0 to 1, 2 to 3, and 4 to 5 special designations, respectively. Multiple special designations were associated with higher biotechnological and clinical innovation. Median patient enrollment in trials were 615, 471, 398, 168, 104, and 120 (P < .001) for indications with 0 to 5 special designations. Drugs for rare diseases supported by open-label phase 1/2 trials of single-arm design were granted more special designations. Hazard ratios for overall survival (0.80 vs 0.73 vs 0.73 vs 0.69 vs 0.56 vs 0.52; P = .003) and progression-free survival (0.70 vs 0.61 vs 0.59 vs 0.44 vs 0.37 vs 0.67; P < .001) substantially declined while tumor response increased with more special designations. Mean monthly prices increased for drugs with 0 to 4 but not 5 special designations ($21 596 vs $14 753 vs $32 410 vs $41 240 vs $38 703 vs $19 184).

CONCLUSIONS

Multiple special designations are associated with faster clinical development and greater benefits for patients with unmet needs but also with nonrobust trial evidence and a tendency toward higher drug prices.

Walk a mile in my shoes: perspectives towards sharing of health and experience data among individuals living with sickle cell disorder

Background

Advancements in digital health technologies (DHTs) mean people are increasingly recording and managing personal health data. As observed during the COVID-19 pandemic, sharing of such data may provide unrivalled opportunities in advancing our understanding of conditions otherwise poorly understood, including rare conditions.

Methods

A semi-structured focus group (n=25) explored perspectives and experiences of sharing health data among those with a group of rare haematological conditions, sickle cell disorder (SCD). The focus group explored (I) what 'feeling well' looks like; (II) how this could be monitored using DHTs; (III) which data healthcare professionals (HCPs) should pay greater attention to and; (IV) types of data willing to be shared, with whom, and under which conditions. Key themes were further assessed via an online survey (n=50).

Results

Patient-relevant measures of condition-management focused on "everything else that comes with" SCD, suggesting HCPs did not pay sufficient attention to day-to-day symptom variability. This was juxtaposed against the "fixed and one-off" electronic health record (EHR), collecting pre-specified data at pre-determined snapshots of time, not considered reflective of outcomes associated with "feeling well" day-to-day. Forty-four-point-seven percent of respondents had previously shared health data. Most were willing to share data concerning symptoms and health service utilisation, but were less willing to share genomic and EHR data. Sixty-one-point-seven percent believed HCPs did not pay enough attention to daily fluctuations in mental and physical health. Financial benefits (74.5%), trust in organisations seeking data (72.3%), and knowing how data will be used (61.7%) were key facilitators of data sharing. Seventy-one percent, 70% and 65.2% had not previously shared health data with the pharmaceutical industry, charitable organisations and digital health interventions respectively, but were open to doing so in the future.

Conclusions

Those living with the rare condition SCD were supportive of collecting and sharing data to foster research and improve understanding and outcomes. However, specific requirements were identified to respect privacy and informational needs regarding future use of data. DHTs can be a valuable tool in improving understanding of the day-to-day impact of health conditions, but understanding patient needs is critical in ensuring involvement in the process, as not all data types are considered of equal value, benefit, or risk.

Knowledge and Attitudes of Clinical Trials among Patients with Rare Diseases and the Guardians in China

BACKGROUND

Conducting of clinical trials for rare diseases faces multiple challenges. Patients' cognition and attitude toward clinical trials are crucial, which may affect their participation and compliance, and affect the schedule of clinical trials eventually.

OBJECTIVE AND METHOD

This study aims to explore the knowledge and attitudes of clinical trials of patients with rare diseases or patients' guardians. An anonymous cross-sectional survey was conducted from November 1, 2021, to November 30, 2021. A total of 1131 valid questionnaires were included. Among them, 417 were filled in by the patients themselves, and 714 were answered by the patients' guardians.

RESULTS

The average score of clinical trial knowledge of the patients (8.25) was lower than that of the guardians (8.85). The willingness of the patients to participate in clinical trials was high (4.28), and the willingness of the patients' guardians was also high for patients to participate in clinical trials (4.35). The main promoting factors of clinical trial participation were the possibility of curing the disease. The main hindering factors of participation in clinical trials were lack of access to clinical trial information and concern about the safety and effectiveness of the trial drug.

CONCLUSIONS

In conclusion, most respondents had some basic knowledge of clinical trials and high willingness to participate in clinical trials. But there were some cognitive deficiencies about clinical trials and many hindering factors to participate in clinical trials. Clinical trials of rare diseases should be patient-centered and truly meet the unmet clinical, psychological, and social needs of patients with rare diseases.

The clinical trials puzzle: How network effects limit drug discovery

The depth of knowledge offered by post-genomic medicine has carried the promise of new drugs, and cures for multiple diseases. To explore the degree to which this capability has materialized, we extract meta-data from 356,403 clinical trials spanning four decades, aiming to offer mechanistic insights into the innovation practices in drug discovery. We find that convention dominates over innovation, as over 96% of the recorded trials focus on previously tested drug targets, and the tested drugs target only 12% of the human interactome. If current patterns persist, it would take 170 years to target all druggable proteins. We uncover two network-based fundamental mechanisms that currently limit target discovery: preferential attachment, leading to the repeated exploration of previously targeted proteins; and local network effects, limiting exploration to proteins interacting with highly explored proteins. We build on these insights to develop a quantitative network-based model to enhance drug discovery in clinical trials.

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.

Economic Burden of Sanfilippo Syndrome in the United States

Introduction

Sanfilippo syndrome is a rare disease and fatal genetic disorder with no FDA-approved treatment in the United States (US), and no comprehensive assessment of economic disease burden is available.

Objectives

To develop a model to estimate the economic burden associated with Sanfilippo syndrome in the US using direct costs, indirect costs and valued intangibles (disability-adjusted life years, or DALYs) from 2023 onward.

Design and Setting

A multistage comorbidity model was generated based on Sanfilippo syndrome symptoms, and disability weights from the 2010 Global Burden of Disease Study. Attributable increase in caregiver mental health burden were estimated using data from the CDC National Comorbidity Survey and retrospective studies on caregiver burden. Direct costs were approximated from the 2019 EveryLife Foundation survey, and indirect costs were estimated from Federal income data. Monetary valuations were adjusted to USD 2023 and given a 3% discount rate from 2023 onward.

Main Outcome Measures

Incidence of Sanfilippo syndrome was calculated for each year, and year-over-year DALYs due to patient years lived with disability (YLDs) and years life lost (YLLs) were calculated by comparing to the health-adjusted life expectancy (HALE) in the US. Direct and indirect costs were calculated for each simulated patient from onset of symptoms to death.

Results

From 2023-2043, overall economic burden in the US attributable to Sanfilippo syndrome was estimated to be $2.04 billion USD present value (2023) with current standard of care. The burden to individual families exceeded $8 million present value from time of birth per child born with Sanfilippo syndrome.

Conclusion

Sanfilippo syndrome is a rare lysosomal storage disease, however the severe burden associated with the disease for individual families demonstrates a considerable cumulative impact. Our model represents the first disease burden value estimate associated with Sanfilippo syndrome, and underscores the substantial morbidity and mortality burden of Sanfilippo syndrome.

Clinical Trials on Cellular Therapy for Children and Adolescents With Cancer: A 15-Year Trend in the United States

INTRODUCTION

Cellular therapies are frequently studied in clinical trials for pediatric patients with malignant disease. Characteristics of ongoing and completed cellular therapy clinical trials in the U.S. involving children and adolescents have not previously been reported.

METHODS

We searched ClinicalTrials.gov for clinical trials involving cellular therapies enrolling patients under 18 years of age in the U.S. Trials were initially stratified into child-only (maximum age of eligibility <18 years), child/adolescent and young adult (AYA) (maximum age of eligibility ≤21 years), and child/adult (maximum age of eligibility >21 years). Descriptive characteristics and trends over time were analyzed.

RESULTS

We included 202 trials posted 2007-2022. Of the 202 trials, only three trials were child-only; thus, our subsequent analysis focused on comparing child/AYA (≤21 years) and child/adult trials (>21 years). One hundred sixty-nine (84%) enrolled both child and adult populations. The vast majority of trials were early phase (phase 1, 1/2, and 2, 198/202, 98%). Chimeric antigen receptor T cell therapies were most commonly studied (88/202, 44%), while natural-killer cell therapies were most common in child/AYA trials (42% vs. 16%). Most trials were single institution-only (130/202, 64%) and did not receive industry funding (163/202, 81%). Studies with industry funding were more likely to be multicenter (64% vs. 29%) and international (31% vs. 0.6%). Notably, no central nervous system tumor-specific trials had industry funding. There was no difference in therapy type based on funding source. Yearly new trial activations increased over the time period studied (p=0.01).

CONCLUSION

The frequency of cellular therapy trial activations enrolling child/AYA patients with cancer in the U.S. has increased over time. Most studies were phase 1 or 2, single institution-only, and not industry-supported. Future opportunities for cell therapy for pediatric cancer should include multi-institutional approaches.

The use of digital outcome measures in clinical trials in rare neurological diseases: a systematic literature review

Developing drugs for rare diseases is challenging, and the precision and objectivity of outcome measures is critical to this process. In recent years, a number of technologies have increasingly been used for remote monitoring of patient health. We report a systematic literature review that aims to summarize the current state of progress with regard to the use of digital outcome measures for real-life motor function assessment of patients with rare neurological diseases. Our search of published literature identified 3826 records, of which 139 were included across 27 different diseases. This review shows that use of digital outcome measures for motor function outside a clinical setting is feasible and employed in a broad range of diseases, although we found few outcome measures that have been robustly validated and adopted as endpoints in clinical trials. Future research should focus on validation of devices, variables, and algorithms to allow for regulatory qualification and widespread adoption.

Randomized controlled trial data for successful new drug application for rare diseases in the United States

BACKGROUND

Randomized controlled trial (RCT) data have important implications in drug development. However, the feasibility and cost of conducting RCTs lower the motivation for drug development, especially for rare diseases. We investigated the potential factors associated with the need for RCTs in the clinical data package for new drug applications for rare diseases in the United States (US). This study focused on 233 drugs with orphan drug designations approved in the US between April 2001 and March 2021. Univariable and multivariable logistic regression analyses were conducted to investigate the association between the presence or absence of RCTs in the clinical data package for new drug applications.

RESULTS

Multivariable logistic regression analysis showed that the severity of the disease outcome (odds ratio [OR] 5.63, 95% confidence interval [CI] 2.64-12.00), type of drug usage (odds ratio [OR] 2.95, 95% confidence interval [CI] 1.80-18.57), and type of primary endpoint (OR 5.57, 95% CI 2.57-12.06) were associated with the presence or absence of RCTs.

CONCLUSIONS

Our results indicated that the presence or absence of RCT data in the clinical data package for successful new drug application in the US was associated with three factors: severity of disease outcome, type of drug usage, and type of primary endpoint. These results highlight the importance of selecting target diseases and potential efficacy variables to optimize orphan drug development.

Evaluation of clinical trials done for orphan drugs versus nonorphan drugs in infectious diseasesan eleven year analysis [2010-2020]

Background

The 1983 US Orphan Drug Act provided impetus for the development of new therapies for rare diseases. Several studies focused on the number of orphan designations over time. However, very few focused on clinical trials that lead to their approval, particularly for infectious diseases.

Materials and Methods

All new drug approvals (orphan and non-orphan) by the US Food and Drug Administration (FDA) from January 2010 to December 31, 2020, were identified and details of approvals were taken from the US-FDA labels and summary reports for each drug. The pivotal trials for each were characterized based on their design. We tested the association of the type of drug approval with respect to the characteristics of trial using Chi-square test and generated crude odds ratios with 95% confidence intervals.

Results

From the total 1122 drugs approved, 84 were for infectious diseases, of which 18 were orphan drugs and 66 were nonorphan. A total of 35 pivotal trials supported 18 orphan drug approvals, while 115 pivotal trials supported 66 nonorphan drugs. The median number of participants enrolled/trial for orphan drugs was 89, while for nonorphan drugs, it was 452 (P < 0.0001). Blinding was done for 13/35 (37%) orphan drugs versus 69/115 (60%) nonorphan drugs (P = 0.029); randomization was done for 15/35 (42%) orphan drugs versus 100/115 (87%) nonorphan drugs (P < 0.0001) and 20/35 (57%) of the orphan drugs got approval in phase II versus 8/115 (6%) of nonorphan drugs (P < 0.00001).

Conclusion

A significant number of orphan drugs get approval based on early phase, nonrandomized, and unblinded with a smaller sample size as compared to nonorphan drugs.

Study design challenges and strategies in clinical trials for rare diseases: Lessons learned from pantothenate kinase-associated neurodegeneration

Substantial challenges in study design and methodology exist during clinical trial development to examine treatment response in patients with a rare disease, especially those with predominant central nervous system involvement and heterogeneity in clinical manifestations and natural history. Here we discuss crucial decisions which may significantly impact success of the study, including patient selection and recruitment, identification and selection of endpoints, determination of the study duration, consideration of control groups including natural history controls, and selection of appropriate statistical analyses. We review strategies for the successful development of a clinical trial to evaluate treatment of a rare disease with a focus on inborn errors of metabolism (IEMs) that present with movement disorders. The strategies presented using pantothenate kinase-associated neurodegeneration (PKAN) as the rare disease example can be applied to other rare diseases, particularly IEMs with movement disorders (e.g., other neurodegeneration with brain iron accumulation disorders, lysosomal storage disorders). The significant challenges associated with designing a clinical trial in rare disease can sometimes be successfully met through strategic engagement with experts in the rare disease, seeking regulatory and biostatistical guidance, and early involvement of patients and families. In addition to these strategies, we discuss the urgent need for a paradigm shift within the regulatory processes to help accelerate medical product development and bring new innovations and advances to patients with rare neurodegenerative diseases who need them earlier in disease progression and prior to clinical manifestations.

Trend of drug clinical trials in mainland China from 2009 to 2020

With the development of linnovative regulations on drug clinical trials in mainland China, the quantity and quality of drug clinical trials have gradually improved over the past decade. Based on the information of the clinical trials from the online drug clinical trial registration platform of National Medical Products Administration, we reviewed the data of drug clinical trials in mainland China from 2009 to 2020. A total of 8,593 clinical trials have been conducted during this period. The annual number of clinical trials has been increasing gradually, and peaked in 2017. There were 2,127, 1,051, 1,551, and 156 phases I, II, III, and IV clinical trials respectively. In addition, there were 3,441 bioequivalence studies. Trials for anti-tumor drugs ranked the highest (19.45%), followed by trials of drugs for infections and infestations (12.96%) and those for cardiovascular diseases (9.00%). Meanwhile the number of the clinical trial sites also increased annually. However, there were only 116 and 130 clinical trials of drugs for children and rare diseases respectively. The geographical distribution of the sites was uneven. This mapping review provides an overall look of clinical trials in China, which may be useful for domestic and international sponsors.

Accrual-Monitoring Practices for Various Disease Trials among AACI Member Cancer Centers

Progress in the management of rare diseases, including rare cancers, is dependent upon clinical trials; however, as many as 32% of rare-disease trials go uncompleted or unpublished due to insufficient accrual. Monitoring practices may differ between institutions. We sought to survey the regulatory standards for various trial types among major U.S. cancer centers. A 10-question survey was designed using Qualtrics assessment software. The survey was sent via email to an internal server of member institutions of the Association of American Cancer Institutes (AACI). Of 103 AACI centers, 31% completed the survey (n = 32). Respondents differed in their definitions of a rare disease, minimum expectations for rare tumor studies, and frequency of accrual monitoring by their institutional Protocol Review and Monitoring Committee. Seventy-three percent of respondents did not close trials based on low accrual. Strategies to optimize accrual included investigator incentives for high accrual and penalties for low accrual in 37% and 13% of respondents, respectively.

Enhanced rare disease mapping for phenome-wide genetic association in the UK Biobank

BACKGROUND

Rare diseases collectively affect up to 10% of the population, but often lack effective treatment, and typically little is known about their pathophysiology. Major challenges include suboptimal phenotype mapping and limited statistical power. Population biobanks, such as the UK Biobank, recruit many individuals who can be affected by rare diseases; however, investigation into their utility for rare disease research remains limited. We hypothesized the UK Biobank can be used as a unique population assay for rare diseases in the general population.

METHODS

We constructed a consensus mapping between ICD-10 codes and ORPHA codes for rare diseases, then identified individuals with each rare condition in the UK Biobank, and investigated their age at recruitment, sex bias, and comorbidity distributions. Using exome sequencing data from 167,246 individuals of European ancestry, we performed genetic association controlling for case/control imbalance (SAIGE) to identify potential rare pathogenic variants for each disease.

RESULTS

Using our mapping approach, we identified and characterized 420 rare diseases affecting 23,575 individuals in the UK Biobank. Significant genetic associations included JAK2 V617F for immune thrombocytopenic purpura (p = 1.24 × 10^-13) and a novel CALR loss of function variant for essential thrombocythemia (p = 1.59 × 10^-13). We constructed an interactive resource highlighting demographic information ( http://www-personal.umich.edu/~mattpat/rareDiseases.html ) and demonstrate transferability by applying our mapping to a medical claims database.

CONCLUSIONS

Enhanced disease mapping and increased power from population biobanks can elucidate the demographics and genetic associations for rare diseases.

Current status and trend of clinical development of orphan drugs in China

BACKGROUND

Rare diseases have been increasingly recognized as unmet medical and health needs worldwide; a growing demand for the development of orphan drugs emerges subsequently. Therefore, it is of great interest for both the Chinese regulatory agency and pharmaceutical companies to keep tract on the clinical development of orphan drugs in China.

OBJECTIVE AND METHOD

This study aims to reveal the current situation and trend of the clinical development of orphan drugs in China, based on the data collected from the Chinese official platform, dating from January 1, 2013 to December 31, 2021.

RESULTS

A total of 331 clinical trials for orphan drugs were extracted from the platform, covering 31 rare diseases and 124 drugs. Increases were seen in the annual number of clinical trials and drugs being tested, with a sharp increase after 2018. About the disease types of the 331 trials, Parkinson disease (young-onset, early-onset) (86, 26%), hemophilia (70, 21%), homozygote hypercholesterolemia (60, 18%) were the most common. Furthermore, it was also observed that the largest number of clinical trial units for rare disease in east China (90, 41%) and the smallest number located in northwest China (18, 6%) and northeast China (18, 6%).

CONCLUSIONS

The growth trends illustrate the progress in clinical trial and drug development of rare diseases from 2013 to 2021. However, promoting orphan drugs development still is an important issue in China; at the same time, further efforts should be made for meet the unmet needs of disease types and balance the uneven distribution of medical resources for clinical trial on rare diseases.

Development and implementation of the AIDA international registry for patients with Schnitzler's syndrome

Objective

The present paper describes the design, development, and implementation of the AutoInflammatory Disease Alliance (AIDA) International Registry specifically dedicated to patients with Schnitzler's syndrome.

Methods

This is a clinical physician-driven, population- and electronic-based registry implemented for the retrospective and prospective collection of real-life data from patients with Schnitzler's syndrome; the registry is based on the Research Electronic Data Capture (REDCap) tool, which is designed to collect standardized information for clinical research, and has been realized to change over time according to future scientific acquisitions and potentially communicate with other existing or future similar registries.

Results

Since its launch, 113 centers from 23 countries in 4 continents have been involved. Fifty-seven have already obtained the approval from their local Ethics Committees. The platform counts 324 users (114 Principal Investigators, 205 Site Investigators, 2 Lead Investigators, and 3 data managers) at current (April 28th, 2022). The registry collects baseline and follow-up data using 3,924 fields organized into 25 instruments, including patient's demographics, history, clinical manifestations and symptoms, trigger/risk factors, laboratory, instrumental exams, therapies, socioeconomic information, and healthcare access.

Conclusions

This International Registry for patients with Schnitzler's syndrome facilitates standardized data collection, enabling international collaborative projects through data sharing and dissemination of knowledge; in turn, it will shed light into many blind spots characterizing this complex autoinflammatory disorder.

Randomized Controlled Trial Data for New Drug Application for Rare Diseases in Japan

BACKGROUND

High-quality evidence is often not obtained in the clinical trials of rare diseases because these trials tend to be smaller in size and non-controlled. We investigated the potential factors associated with the need for randomized controlled trials (RCTs) in the clinical data package for new drug applications for rare diseases in Japan.

METHODS

This study focused on 130 drugs with orphan drug designation approved in Japan between April 2004 and March 2020.

RESULTS

Multivariable regression analysis showed that the prevalence (odds ratio [OR] 3.21, 95% confidence interval [CI] 1.18-8.6) and the type of primary endpoint (OR 6.66, 95% CI 2.41-18.37) were associated with the need for RCTs in the clinical data package in Japan.

CONCLUSIONS

Our findings highlight the importance of adequate understanding of the target disease in new drug development for rare diseases.

Treatment effectiveness in a rare oncology indication: Lessons from an external control cohort study

Real-world data (RWD) reflecting patient treatment in routine clinical practice can be used to develop external control groups for single-arm trials. External controls can provide valuable benchmark results on potential comparator drug effectiveness, particularly in rare indications when randomized controlled trials are either infeasible or unethical. This paper describes lessons learned from a descriptive real-world external control cohort study conducted to provide benchmark data for a single-arm clinical trial in a rare oncology biomarker driven disease. Conducting external control cohort studies to evaluate treatment effectiveness in rare indications likely will present with data and analysis challenges as seen in the example study. However, there are mitigating measures that can be applied in the study design, identification of RWD sources, and data analysis. The lessons learned and reported here with a proposal of an external control study framework can provide guidance for future research in this area, and may be applicable as well in other rare indications. Taking these learnings into consideration, the use of real-world external controls to contextualize treatment effectiveness in rare indications is a valuable approach and warrants further application in the future.

Inequities in cancer drug development in terms of unmet medical need

This study measures inequality and inequity in the distribution of clinical trials on cancer drug development between 1996 and 2016, comparing the number of clinical trials with cancer need, proxied by prevalence, incidence, or survival rates for both rare and non-rare cancers. We leverage a unique global database of clinical trials activity and costs between 1996 and 2016, constructed for 227 different cancer types to measure for rare and non-rare cancers: i) inequalities and inequity of clinical trial activity, considering all trials as well as split by R&D stage; ii) inequalities and inequity in R&D investment proxied by trial enrollment and duration; iii) evolution of inequity over time. Inequalities are measured with concentration curves and indices and inequities measured with the health inequity index. We find four important results. First, we show pro-low need inequity across cancer types for both rare and non-rare cancers, for all need proxies. Second, we show inequity differs across R&D stages and between rare and non-rare cancers. The distribution of clinical trials for non-rare cancers disproportionately favors low-need non-rare cancers from earlier to later stages of R&D, whilst for rare cancers this only occurs in Phase 2 trials. Third, inequity analyses in R&D investment show that only trial enrollment for rare cancers and trial duration for non-rare cancers are disproportionately concentrated among low-need cancers. Finally, while pro-low need inequity has persisted between 1996 and 2016 for non-rare cancers, it has faded for rare cancers post-EU orphan drugs' legislation.

Optimal sample size determination for single-arm trials in pediatric and rare populations with Bayesian borrowing

In many therapeutic areas with unmet medical needs, such as pediatric oncology and rare diseases, one of the deterrent factors for clinical trial interpretability is the limited sample size with less-than-ideal operating characteristics. Single arm is usually the only viable design due to feasibility and ethical concerns. For the trial results to be more interpretable and conclusive, the evaluation of operating characteristics, such as type I error rate and power, and the appropriate utilization of prior information for study design, shall be prespecified and fully investigated during the trial planning phase. So far, very few existing literature addressed optimal sample size determination issues for the planning of pediatric and rare population trials, with majority of research focusing on analysis perspective with focus on Bayesian borrowing. In practice, when a single-arm trial is designed for rare population, it is not uncommon that the only information available is from an earlier trial and/or a few clinical publications based on observational studies, often constituting mixed or uncertain conclusions. In light of this, an optimal Bayesian sample size determination method for single-arm trial with binary or continuous endpoint is proposed, where conflicting prior beliefs can be readily incorporated. Prior effective sample size can be calculated to assess the robustness as well as the prior information borrowed. Moreover, due to the lack of closed-form posterior distributions in general, an alternative approach for calculating Bayesian power is described. Simulation studies are provided to demonstrate the utility of the proposed methods. In addition, a case study in pediatric patients with leukemia is included to illustrate the proposed method with the existing approaches.

Application of Bayesian methods to accelerate rare disease drug development: scopes and hurdles

Background

Design and analysis of clinical trials for rare and ultra-rare disease pose unique challenges to the practitioners. Meeting conventional power requirements is infeasible for diseases where sample sizes are inherently very small. Moreover, rare disease populations are generally heterogeneous and widely dispersed, which complicates study enrollment and design. Leveraging all available information in rare and ultra-rare disease trials can improve both drug development and informed decision-making processes.

Main text

Bayesian statistics provides a formal framework for combining all relevant information at all stages of the clinical trial, including trial design, execution, and analysis. This manuscript provides an overview of different Bayesian methods applicable to clinical trials in rare disease. We present real or hypothetical case studies that address the key needs of rare disease drug development highlighting several specific Bayesian examples of clinical trials. Advantages and hurdles of these approaches are discussed in detail. In addition, we emphasize the practical and regulatory aspects in the context of real-life applications.

Conclusion

The use of innovative trial designs such as master protocols and complex adaptive designs in conjunction with a Bayesian approach may help to reduce sample size, select the correct treatment and population, and accurately and reliably assess the treatment effect in the rare disease setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02342-5.

Bayesian modeling and simulation to inform rare disease drug development early decision-making: Application to Duchenne muscular dystrophy

Rare disease clinical trials are constrained to small sample sizes and may lack placebo-control, leading to challenges in drug development. This paper proposes a Bayesian model-based framework for early go/no-go decision making in rare disease drug development, using Duchenne muscular dystrophy (DMD) as an example. Early go/no-go decisions were based on projections of long-term functional outcomes from a Bayesian model-based analysis of short-term trial data informed by prior knowledge based on 6MWT natural history literature data in DMD patients. Frequentist hypothesis tests were also applied as a reference analysis method. A number of combinations of hypothetical trial designs, drug effects and cohort comparison methods were assessed. The proposed Bayesian model-based framework was superior to the frequentist method for making go/no-go decisions across all trial designs and cohort comparison methods in DMD. The average decision accuracy rates across all trial designs for the Bayesian and frequentist analysis methods were 45.8 and 8.98%, respectively. A decision accuracy rate of at least 50% was achieved for 42 and 7% of the trial designs under the Bayesian and frequentist analysis methods, respectively. The frequentist method was limited to the short-term trial data only, while the Bayesian methods were informed with both the short-term data and prior information. The specific results of the DMD case study were limited due to incomplete specification of individual-specific covariates in the natural history literature data and should be reevaluated using a full natural history dataset. These limitations aside, the framework presented provides a proof of concept for the utility of Bayesian model-based methods for decision making in rare disease trials.

A survey of patients with laryngotracheal stenosis on future clinical trial design

BACKGROUND/AIMS

Laryngotracheal stenosis is a rare but devastating proximal airway fibrosis that restricts a patient's ability to breathe. Treatment is primarily surgical and to date, there has never been a multi-institutional, randomized, prospective, and interventional clinical trial for a medical therapy to treat laryngotracheal stenosis. Therefore, we aimed to obtain patient feedback to guide successful trial design, recruitment, retention, and for identifying potential barriers to study participation.

METHODS

Over 1000 members of an international laryngotracheal stenosis online support community (the Living with Idiopathic Subglottic Stenosis Facebook group) were sent two questionnaires for a proposed interventional double-blinded, randomized, placebo-controlled clinical trial.

RESULTS

A total of 317 and 558 participants responded to the first and second surveys, respectively. The majority of participants (77%) were willing to consider enrollment, regardless of having a 50% chance of receiving placebo versus treatment (78%). The majority (84%) of participants were willing to travel 200 miles to participate for up to six in-person visits over 50 days. Specific side effects, including anemia/thrombocytopenia (72%) or risk of infection (69.3%) had the greatest impact on clinical trial participation with other side effects (peripheral edema (53%), oral ulcers (51%), and gastrointestinal side effects (41%)) having less impact.

CONCLUSION

Patients with laryngotracheal stenosis possess nuanced insight into their disease and treatment options. As a group, they are extremely motivated for better therapies. Future laryngotracheal stenosis clinical trials should focus on providing excellent side effect -related education and utilizing feedback from online advocacy groups to optimize recruitment and retention.

Postmarketing safety of orphan drugs: a longitudinal analysis of the US Food and Drug Administration database between 1999 and 2018

Background

Information about the specific regulatory environment of orphan drugs is scarce and inconsistent. Uncertainties surrounding the postmarketing long-term safety of orphan drugs remain. This study aimed to evaluate the labelling changes of orphan drugs and to identify postmarketing safety-associated approval factors.

Methods

This retrospective cohort study includes all drugs with orphan drug designation approved by the Center for Drug Evaluation and Research of the US Food and Drug Administration between 1999 and 2018. Main outcomes are safety-related labelling changes up to 31 December 2019. We defined any safety-related labelling changes as postmarketing safety events (PMSE). Safety-related withdrawals, suspensions, and boxed warnings were further categorised as severe postmarketing safety events (SPSE). Outcome measurements include frequencies of PMSE, SPSE, and association between approval factors and the occurrence of safety events.

Results

Amongst the 214 drugs identified with orphan drug designation (25.7% biologics), 83.6% were approved through at least one expedited programme, and 29.4% were approved with boxed warnings. During a median follow-up of 6.74 years since approval, 69.2% and 14.5% of the analysed orphan drugs had PMSE and SPSE, respectively. Safety-related withdrawal (0%, 0/214), suspended marketing (0.46%, 1/214) and new boxed warnings are uncommon (3.7%, 8/214). The safety-related labelling changes were more frequent in the drugs approved with boxed warnings [Incidence rate ratio (IRR): 1.95 (1.02–3.73)] and approved for long-term use [IRR: 2.76 (1.52–5.00)].

Conclusions and Relevance

In this long-term postmarketing analysis, approximately 70% of FDA-approved orphan drugs had safety-related labelling changes although severe safety events were rare. While maintaining early access to orphan drugs, the drug regulatory body has taken timely regulatory action with postmarketing surveillance to ensure patient safety.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02166-9.

A survey of registered pharmacological clinical trials on rare neurological diseases in children in 2010-2020

OBJECTIVE

To clarify the current state of methodology of clinical trials for rare neurological diseases in children, and to provide a basis for the further optimization of the trial design.

METHODS

Data of clinical trials for the rare neurological diseases with childhood onset (searched through https://rarediseases.info.nih.gov/diseases and www.Orpha.net) registered on the Clinicaltrils.gov from January 2010 to June 2020 was collected. Analysis on the methodology of the clinical trials were performed, focusing on initiator of the studies, multi or single research center, study design, sample size, and the endpoint using in the trial.

RESULTS

A total of 162 clinical trials were included, covering only 7.3% (61/835) of rare neurological diseases in children. 101 (62.3%) were initiated by pharmaceutical companies, and 61 (37.7%) by investigators. Most (95.4%) of global multicenter studies were initiated by pharmaceutical companies, whereas most (70.0%) of single-center studies were initiated by investigators (χ ²= 61.635, P < 0.001). Of the 162 trials, 74 (45.7%) were open-label single-arm trials, 68 (42.0%) were randomized double-blind parallel controlled trials (RCT), 12 (7.4%) were randomized crossover trials. Most of RCTs (73.5%) and 54.1% of open-label single-arm trials were initiated by pharmaceutical companies. The proportion of RCTs in clinical trials for diseases with a prevalence of ≥1/10,000 (62.5%) was higher than that in diseases with prevalence ≤1/1,000,000 (12.0%) or 1/1,000,000~1/10,000 (43.1%) (χ ²= 14.790, P = 0.001). The median expected sample size of the studies was 34 (4-500). 132 (132/162, 81.5%) studies enrolled fewer than 100 cases. Diseases with a prevalence of ≥1/10,000 had significantly larger sample sizes than other prevalence classes (P < 0.001, P = 0.003).

CONCLUSIONS

There were few clinical trials targeting on treatment of rare neurological diseases in children. Trials on rare diseases used fewer participants, and high-quality randomized controlled trials were less common. It is necessary to conduct global multicenter recruitment and choose optimal study designs to improve the level of evidence in clinical trials on rare diseases.

Randomized and non-randomized designs for causal inference with longitudinal data in rare disorders

In the United States, approximately 7000 rare diseases affect 30 million patients, and only 10% of these diseases have existing therapies. Sound study design and causal inference methods are essential to demonstrate the therapeutic efficacy, safety, and effectiveness of new therapies. In the rare diseases setting, several factors challenge the use of typical parallel control designs: the small patient population size, genotypic and phenotypic diversity, and the complexity and incomplete understanding of the disorder’s progression. Repeated measures, when spaced appropriately relative to disease progression and exploited in design and analysis, can increase study power and reduce variability in treatment effect estimation. This paper reviews these longitudinal designs and draws the parallel between some new and existing randomized studies in rare diseases and their less well-known controlled observational study designs. We show that self-controlled randomized crossover and N-of-1 designs have similar considerations as the observational case series and case-crossover designs. Also, randomized sequential designs have similar considerations to longitudinal cohort studies using sequential matching or weighting to control confounding. We discuss design and analysis considerations for valid causal inference and illustrate them with examples of analyses in multiple rare disorders, including urea cycle disorder and cystic fibrosis.

Bayesian Hierarchical Factor Analysis for Efficient Estimation across Race/Ethnicity

Patient reported outcomes are gaining more attention in patient-centered health outcomes research and quality of life studies as important indicators of clinical outcomes, especially for patients with chronic diseases. Factor analysis is ideal for measuring patient reported outcomes. If there is heterogeneity in the patient population and when sample size is small, differential item functioning and convergence issues are challenges for applying factor models. Bayesian hierarchical factor analysis can assess health disparity by assessing for differential item functioning, while avoiding convergence problems. We conducted a simulation study and used an empirical example with American Indian minorities to show that fitting a Bayesian hierarchical factor model is an optimal solution regardless of heterogeneity of population and sample size.

Rise of Clinical Studies in the Field of Machine Learning: A Review of Data Registered in ClinicalTrials.gov

Although advances in machine-learning healthcare applications promise great potential for innovative medical care, few data are available on the translational status of these new technologies. We aimed to provide a comprehensive characterization of the development and status quo of clinical studies in the field of machine learning. For this purpose, we performed a registry-based analysis of machine-learning-related studies that were published and first available in the ClinicalTrials.gov database until 2020, using the database's study classification. In total, n = 358 eligible studies could be included in the analysis. Of these, 82% were initiated by academic institutions/university (hospitals) and 18% by industry sponsors. A total of 96% were national and 4% international. About half of the studies (47%) had at least one recruiting location in a country in North America, followed by Europe (37%) and Asia (15%). Most of the studies reported were initiated in the medical field of imaging (12%), followed by cardiology, psychiatry, anesthesia/intensive care medicine (all 11%) and neurology (10%). Although the majority of the clinical studies were still initiated in an academic research context, the first industry-financed projects on machine-learning-based algorithms are becoming visible. The number of clinical studies with machine-learning-related applications and the variety of medical challenges addressed serve to indicate their increasing importance in future clinical care. Finally, they also set a time frame for the adjustment of medical device-related regulation and governance.

Obstacles to the reuse of study metadata in ClinicalTrials.gov

Metadata that are structured using principled schemas and that use terms from ontologies are essential to making biomedical data findable and reusable for downstream analyses. The largest source of metadata that describes the experimental protocol, funding, and scientific leadership of clinical studies is ClinicalTrials.gov. We evaluated whether values in 302,091 trial records adhere to expected data types and use terms from biomedical ontologies, whether records contain fields required by government regulations, and whether structured elements could replace free-text elements. Contact information, outcome measures, and study design are frequently missing or underspecified. Important fields for search, such as condition and intervention, are not restricted to ontologies, and almost half of the conditions are not denoted by MeSH terms, as recommended. Eligibility criteria are stored as semi-structured free text. Enforcing the presence of all required elements, requiring values for certain fields to be drawn from ontologies, and creating a structured eligibility criteria element would improve the reusability of data from ClinicalTrials.gov in systematic reviews, metanalyses, and matching of eligible patients to trials.

A scoping review of clinical decision support tools that generate new knowledge to support decision making in real time

OBJECTIVE

A growing body of observational data enabled its secondary use to facilitate clinical care for complex cases not covered by the existing evidence. We conducted a scoping review to characterize clinical decision support systems (CDSSs) that generate new knowledge to provide guidance for such cases in real time.

MATERIALS AND METHODS

PubMed, Embase, ProQuest, and IEEE Xplore were searched up to May 2020. The abstracts were screened by 2 reviewers. Full texts of the relevant articles were reviewed by the first author and approved by the second reviewer, accompanied by the screening of articles' references. The details of design, implementation and evaluation of included CDSSs were extracted.

RESULTS

Our search returned 3427 articles, 53 of which describing 25 CDSSs were selected. We identified 8 expert-based and 17 data-driven tools. Sixteen (64%) tools were developed in the United States, with the others mostly in Europe. Most of the tools (n = 16, 64%) were implemented in 1 site, with only 5 being actively used in clinical practice. Patient or quality outcomes were assessed for 3 (18%) CDSSs, 4 (16%) underwent user acceptance or usage testing and 7 (28%) functional testing.

CONCLUSIONS

We found a number of CDSSs that generate new knowledge, although only 1 addressed confounding and bias. Overall, the tools lacked demonstration of their utility. Improvement in clinical and quality outcomes were shown only for a few CDSSs, while the benefits of the others remain unclear. This review suggests a need for a further testing of such CDSSs and, if appropriate, their dissemination.

Treatment of Dystonia: Medications, Neurotoxins, Neuromodulation, and Rehabilitation

Dystonia is a complex disorder with numerous presentations occurring in isolation or in combination with other neurologic symptoms. Its treatment has been significantly improved with the advent of botulinum toxin and deep brain stimulation in recent years, though additional investigation is needed to further refine these interventions. Medications are of critical importance in forms of dopa-responsive dystonia but can be beneficial in other forms of dystonia as well. Many different rehabilitative paradigms have been studied with variable benefit. There is growing interest in noninvasive stimulation as a potential treatment, but with limited long-term benefit shown to date, and additional research is needed. This article reviews existing evidence for treatments from each of these categories. To date, there are many examples of incomplete response to available treatments, and improved therapies are needed.

Inhibitor development in previously untreated patients with severe haemophilia: A comparison of included patients and outcomes between a clinical study and a registry-based study

Aim

The aim of this study was to investigate whether a disease registry could serve as a suitable alternative to clinical studies to investigate safety of orphan drugs in children.

Methods

We used individual patient data from previously untreated patients (PUPs) with severe haemophilia A from the factor VIII (rAHF‐PFM)‐clinical study and the PedNet registry. The primary outcome was the patient characteristics at entry and the difference in inhibitor development between the clinical study and the registry‐based study at 50 exposure days.

Results

Clinical study patients more often had a positive family history of inhibitors (31% vs 10%) and a high‐risk F8 genotype (82% vs 63%). In the clinical study 41/55 (75%) and in the registry‐based study 162/168 (96%) patients reached 50 exposure days. Inhibitors developed in 16 of the 41 patients in the clinical study (39%) vs 44 of the 162 patients in the registry‐based study (27%); seven patients (7%) vs 28 patients (17%) had high‐titre inhibitors. The risk of developing an inhibitor during the first 50 exposure days was similar (HR 1.04; 95% CI 0.56‐1.94), when adjusted for family history of inhibitors, F8 gene mutation and intensive treatment at first exposure.

Conclusion

In the registry‐based study, patient numbers and completeness of follow‐up were higher. The risk of developing an inhibitor to a single product was comparable. Although the sample size of this study was too small to conclude on differences in high‐ or low‐titre inhibitors, this suggests that a registry could serve as a more suitable source for evaluation of high‐titre inhibitors in the setting of factor VIII deficiency.

Current Status of PSMA-Radiotracers for Prostate Cancer: Data Analysis of Prospective Trials Listed on ClinicalTrials.gov

The recent development of dedicated prostate-specific membrane antigen (PSMA) targeted radioligands shows the potential to change and improve the diagnosis and therapy of prostate cancer. There is an increasing number of prospective trials to further establish these tracers in the clinical setting. We analyzed data from the ClinicalTrials.gov registry including all listed prospective trials with PSMA-ligands for prostate cancer as of October 2019 concerning the different tracers and study characteristics. We found n = 104 eligible studies with a total of n = 25 different tracers in use: most frequently [⁶⁸Ga]Ga-PSMA-11 (32%), followed by [¹⁸F]DCFPyL (24%) and [¹⁷⁷Lu]Lu-PSMA-617 (10%). 85% are single-center, 15% multi-center studies. 95% national and 5% international studies. 34% are phase-II, 24% phase-I, 13% phase-I/-II, 12% phase-II/-III and phase-III and 7% early-phase-I. The primary purpose was classified as diagnostic in 72% of cases and therapeutic in 23% of cases. Most studies were executed in the USA (70%), followed by Canada (13%) and France (6%). This quantitative descriptive registry analysis indicates the rapid and global clinical developments and current status of PSMA-radioligands with emphasis on radiopharmaceutical and organizational aspects. It will be very interesting to see which tracers will prevail in the clinical setting.

Trends of Clinical Trials for Drug Development in Rare Diseases

Background

Drug development for rare diseases is challenging because it is difficult to obtain relevant data from very few patients. It must be informative to grasp current status of clinical trials for drug development in rare diseases.

Objective

Clinical trials in rare diseases are to be outlined and compared among the US, EU and Japan.

Method

ClinicalTrials.gov (NCT, National Clinical Trial), EU Clinical Trials Register (EUCTR) and the Japan Primary Registries Network (JPRN) were analyzed. Clinical trials involving information on rare diseases and drugs were extracted by text-mining, based on the diseases and drugs derived from Orphanet and DrugBank, respectively.

Results

In total, 28,526 clinical trials were extracted, which studied 1,535 rare diseases and 1,539 drugs. NCT had the larg-est number of trials, involving 1,252 diseases and 1,332 drugs. EUCTR and JPRN also had registry-specific diseases (250 and 22, respectively) and drugs (172 and 29, respectively) that should not be missed. Among the 1,535 rare diseases, most diseases were studied in only a limited number of trials; 70% of diseases were studied in fewer than 10 trials, and 28% were studied in only one. Additionally, most studied rare diseases were cancer-related ones.

Conclusion

This study has revealed the characteristics of the clinical trials in rare diseases among the US, EU and Japan. The number of trials for rare diseases was limited especially for non-cancer-related ones. This information could contribute to drug development such as drug-repositioning in rare diseases.

Survey of Japanese Orphan Drug Program: Factors Related to Successful Marketing Approval

The basic components of regulatory and supporting policies for orphan drug development appear similar between the United States and Japan, but drugs designated as orphan drugs have been different between the 2 countries. The probabilities of development success (ie, marketing approval) in designated orphan drugs have also been significantly different. In this study, we analyzed recent outcomes of development for orphan drugs designated from 1993 to 2017 in Japan, considering their development and approval status in the United States. Our analysis showed that success for orphan drug development in Japan was apparently associated with prior approval status in the United States. Company size, orphan development experience, and patient enrichment were also positively associated with successful marketing approval. Although similar designations and priority review systems for orphan drugs have been enacted, economic incentives and regulatory conditions provided by the systems seem to be different between the 2 countries, which may lead to varied performance in orphan designation and approval. We need to pay close attention to the impact of industrial global development strategies when comparing the outcomes and performance of different orphan drug promotion systems.

Orphan drug development: the increasing role of clinical pharmacology

Over the last few decades there has been a paradigm shift in orphan drug research and development. The development of the regulatory framework, establishment of rare disease global networks that support drug developments, and advances in technology, has resulted in tremendous growth in orphan drug development. Nevertheless, several challenges during orphan drug development such as economic constraints; insufficient clinical information; fewer patients and thus inadequate power; etc. still exist. While the standard regulatory requirements for drug approval stays the same, applications of scientific judgment and regulatory flexibility is significantly important to help meeting some of the immense unmet medical need in rare diseases. Clinical pharmacology presents a vital role in accelerating orphan drug development and overcoming some of these challenges. This review highlights the critical contributions of clinical pharmacology in orphan drug development; for example, dose finding, optimizing clinical trial design, indication expansion, and population extrapolation. Examples of such applications are reviewed in this article.

The burden of rare diseases

The subject of rare disease numbers is rife with misconceptions, not just in websites and other layman's literature, but also in the medical literature. Various websites mention numbers that are not validated by any solid data, while in turn the medical literature cites the aforementioned websites as sources, thus perpetuating a number of myths about rare diseases and their burden. We review the existing literature on rare disease numbers, in an attempt to demystify the subject. Specifically, we summarize data pertaining to: (a) known number and cumulative prevalence of rare diseases; (b) rare disease-associated mortality; (c) rare disease-associated morbidity, including numbers on health care services related to rare diseases; and (d) orphan drug numbers.