Immune response to enzyme replacement therapies in lysosomal storage diseases and the role of immune tolerance induction.

The US Food and Drug Administration (FDA) and National Organization for Rare Disease (NORD) convened a public workshop titled "Immune Responses to Enzyme Replacement Therapies: Role of Immune Tolerance Induction" to discuss the impact of anti-drug antibodies (ADAs) on efficacy and safety of enzyme replacement therapies (ERTs) intended to treat patients with lysosomal storage diseases (LSDs). Participants in the workshop included FDA staff, clinicians, scientists, patients, industry, and advocacy group representatives. The risks and benefits of implementing prophylactic immune tolerance induction (ITI) to reduce the potential clinical impact of antibody development were considered. Complications due to immune responses to ERT are being recognized with increasing experience and lengths of exposure to ERTs to treat several LSDs. Strategies to mitigate immune responses and to optimize therapies are needed. Discussions during the workshop resulted in the identification of knowledge gaps and future areas of research, as well as the following proposals from the participants: (1) systematic collection of longitudinal data on immunogenicity to better understand the impact of ADAs on long-term clinical outcomes; (2) development of disease-specific biomarkers and outcome measures to assess the effect of ADAs and ITI on efficacy and safety; (3) development of consistent approaches to ADA assays to allow comparisons of immunogenicity data across different products and disease groups, and to expedite reporting of results; (4) establishment of a system to widely share data on antibody titers following treatment with ERTs; (5) identification of components of the protein that are immunogenic so that triggers and components of the immune responses can be targeted in ITI; and (6) consideration of early ITI in patients who are at risk of developing clinically relevant ADA that have been demonstrated to worsen treatment outcomes.

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.

Important role of translational science in rare disease innovation, discovery, and drug development.

Rare diseases play a leading role in innovation and the advancement of medical and pharmaceutical science. Most rare diseases are genetic disorders or atypical manifestations of infectious, immunologic, or oncologic diseases; they all provide opportunities to study extremes of human pathology and provide insight into both normal and aberrant physiology. Recently, drug development has become increasingly focused on classifying diseases largely on genetic grounds; this has allowed the identification of molecularly defined targets and the development of targeted therapies. Clinical trials are now focusing on progressively smaller subgroups within both common and rare disease populations, often based on genetic tests or biomarkers. Drug developers, researchers, and regulatory agencies face a variety of challenges throughout the life cycle of drug research and development for rare diseases. These include the small numbers of patients available for study, lack of knowledge of the disease's natural history, incomplete understanding of the basic mechanisms causing the disorder, and variability in disease severity, expression, and course. Traditional approaches to rare disease clinical research have not kept pace with advances in basic science, and increased attention to translational science is needed to address these challenges, especially diagnostic testing, registries, and novel trial designs.

Operational description of rare diseases: a reference to improve the recognition and visibility of rare diseases.

Improving health and social equity for persons living with a rare disease (PLWRD) is increasingly recognized as a global policy priority. However, there is currently no international alignment on how to define and describe rare diseases. A global reference is needed to establish a mutual understanding to inform a wide range of stakeholders for actions. A multi-stakeholder, global panel of rare disease experts, came together and developed an Operational Description of Rare Diseases. This reference describes which diseases are considered rare, how many persons are affected and why the rare disease population demands specific attention. The operational description of rare diseases is framed in two parts: a core definition of rare diseases, complemented by a descriptive framework of rare diseases. The core definition includes parameters that permit the identification of which diseases are considered rare, and how many persons are affected. The descriptive framework elaborates on the impact and burden of rare diseases on patients, their caregivers and families, healthcare systems, and society overall. The Operational Description of Rare Diseases establishes a common point of reference for decision-makers across the world who strive to understand and address the unmet needs of persons living with a rare disease. Adoption of this reference is essential to improving the visibility of rare conditions in health systems across the world. Greater recognition of the burden of rare diseases will motivate new actions and policies to address the unmet needs of the rare disease community.

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.

Successfully Navigating Food and Drug Administration Orphan Drug and Rare Pediatric Disease Designations for AAV9-hPCCA Gene Therapy: The National Institutes of Health Platform Vector Gene Therapy Experience.

Orphan drug designation (ODD) is an important program intended to facilitate the development of orphan drugs in the United States. An orphan drug benefiting pediatric patients can qualify as a drug for a Rare Pediatric Disease Designation (RPDD) as well. The ODD and RPDD programs provide financial incentives for development of diagnostic drugs, preventive measures, and treatment of diseases affecting small patient populations (adult and pediatric) for which commercial development would otherwise be very challenging. In 2019, a multidisciplinary group of collaborators at National Institutes of Health (NIH) embarked upon a gene therapy platform program called Platform Vector Gene Therapy (PaVe-GT) intended to develop gene therapies for four such rare disorders. An important part of PaVe-GT is to publicly share scientific and regulatory experience gained at different stages during the implementation of the PaVe-GT platform utilizing illustrative examples. The PaVe-GT team recently obtained ODD and RPDD for an adeno-associated virus gene therapy to treat propionic acidemia. Given an increasing interest in obtaining ODD for gene therapy, especially by small companies, research investigators, and patient groups, we overview the submission process and subsequently provide examples of our ODD and RPDD applications. Our ODD and RPDD applications and templates can also be found on the PaVe-GT website. Shared reference documents will have great utility to assist parties who may have limited experience with the preparation of similar applications for their orphan product.

Towards the international interoperability of clinical research networks for rare diseases: recommendations from the IRDiRC Task Force.

BACKGROUND: Many patients with rare diseases are still lacking a timely diagnosis and approved therapies for their condition despite the tremendous efforts of the research community, biopharmaceutical, medical device industries, and patient support groups. The development of clinical research networks for rare diseases offers a tremendous opportunity for patients and multi-disciplinary teams to collaborate, share expertise, gain better understanding on specific rare diseases, and accelerate clinical research and innovation. Clinical Research Networks have been developed at a national or continental level, but global collaborative efforts to connect them are still lacking. The International Rare Diseases Research Consortium set a Task Force on Clinical Research Networks for Rare Diseases with the objective to analyse the structure and attributes of these networks and to identify the barriers and needs preventing their international collaboration. The Task Force created a survey and sent it to pre-identified clinical research networks located worldwide. RESULTS: A total of 34 responses were received. The survey analysis demonstrated that clinical research networks are diverse in their membership composition and emphasize community partnerships including patient groups, health care providers and researchers. The sustainability of the networks is mostly supported by public funding. Activities and research carried out at the networks span the research continuum from basic to clinical to translational research studies. Key elements and infrastructures conducive to collaboration are well adopted by the networks, but barriers to international interoperability are clearly identified. These hurdles can be grouped into five categories: funding limitation; lack of harmonization in regulatory and contracting process; need for common tools and data standards; need for a governance framework and coordination structures; and lack of awareness and robust interactions between networks. CONCLUSIONS: Through this analysis, the Task Force identified key elements that should support both developing and established clinical research networks for rare diseases in implementing the appropriate structures to achieve international interoperability worldwide. A global roadmap of actions and a specific research agenda, as suggested by this group, provides a platform to identify common goals between these networks.

The role of immune tolerance induction in restoration of the efficacy of ERT in Pompe disease.

Pompe disease is a lysosomal storage disorder caused by deficiency in the enzyme acid α-glucosidase (GAA). Pompe disease is characterized by the accumulation of glycogen, predominantly in muscle tissue, leading to progressive muscle weakness, loss of motor, respiratory, and, in the infantile-onset form, cardiac function. Disease progression is highly variable depending on phenotype, but premature death due to respiratory complications occurs in most patients. Beginning in 2006, approved alglucosidase alfa enzyme replacement therapies [recombinant human (rh) GAA] have been available to treat Pompe patients. Treatment of classic infantile-onset patients, who manifest the severest form of the disease, with alglucosidase alfa (Myozyme®) has led to extended survival and an evolving understanding of the pathophysiology and course of the disease. Moreover, such treatment has brought to light the role of the immune response in abrogating the efficacy of rhGAA in classic infantile-onset patients with severe genetic mutations. Thus, optimization of treatment for such patients includes development and utilization of strategies to prevent or eliminate immune responses, including modulating the immune system (prophylactic and therapeutic immune tolerance induction regimens) and engineering the enzyme to be less immunogenic and more effective. Future research is also critical for evaluating and mitigating novel disease-associated pathologies uncovered by prolonged survival of infantile-onset patients including development of novel therapeutics, and for protein design strategies to increase delivery of enzyme replacement therapy to critical target tissues. Such efforts would be greatly bolstered by further development of predictive animal models and biomarkers to facilitate clinical trials and patient management. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

The IDeaS initiative: pilot study to assess the impact of rare diseases on patients and healthcare systems.

BACKGROUND: Rare diseases (RD) are a diverse collection of more than 7-10,000 different disorders, most of which affect a small number of people per disease. Because of their rarity and fragmentation of patients across thousands of different disorders, the medical needs of RD patients are not well recognized or quantified in healthcare systems (HCS). METHODOLOGY: We performed a pilot IDeaS study, where we attempted to quantify the number of RD patients and the direct medical costs of 14 representative RD within 4 different HCS databases and performed a preliminary analysis of the diagnostic journey for selected RD patients. RESULTS: The overall findings were notable for: (1) RD patients are difficult to quantify in HCS using ICD coding search criteria, which likely results in under-counting and under-estimation of their true impact to HCS; (2) per patient direct medical costs of RD are high, estimated to be around three-fivefold higher than age-matched controls; and (3) preliminary evidence shows that diagnostic journeys are likely prolonged in many patients, and may result in progressive, irreversible, and costly complications of their disease CONCLUSIONS: The results of this small pilot suggest that RD have high medical burdens to patients and HCS, and collectively represent a major impact to the public health. Machine-learning strategies applied to HCS databases and medical records using sentinel disease and patient characteristics may hold promise for faster and more accurate diagnosis for many RD patients and should be explored to help address the high unmet medical needs of RD patients.

Recent Advances in Systems and Network Medicine: Meeting Report from the First International Conference in Systems and Network Medicine.

The First International Conference in Systems and Network Medicine gathered together 200 global thought leaders, scientists, clinicians, academicians, industry and government experts, medical and graduate students, postdoctoral scholars and policymakers. Held at Georgetown University Conference Center in Washington D.C. on September 11-13, 2019, the event featured a day of pre-conference lectures and hands-on bioinformatic computational workshops followed by two days of deep and diverse scientific talks, panel discussions with eminent thought leaders, and scientific poster presentations. Topics ranged from: Systems and Network Medicine in Clinical Practice; the role of -omics technologies in Health Care; the role of Education and Ethics in Clinical Practice, Systems Thinking, and Rare Diseases; and the role of Artificial Intelligence in Medicine. The conference served as a unique nexus for interdisciplinary discovery and dialogue and fostered formation of new insights and possibilities for health care systems advances.

From scientific discovery to treatments for rare diseases - the view from the National Center for Advancing Translational Sciences - Office of Rare Diseases Research.

We now live in a time of unprecedented opportunities to turn scientific discoveries into better treatments for the estimated 30 million people in the US living with rare diseases. Despite these scientific advances, more than 90% of rare diseases still lack an effective treatment. New data and genetics technologies have resulted in the first transformational new treatments for a handful of rare diseases. This challenges us as a society to accelerate progress so that no disease and no patient is, ultimately, left behind in getting access to safe and effective therapeutics. This article reviews initiatives of the National Center for Advancing Translational Sciences (NCATS) Office of Rare Diseases Research (ORDR) that are aimed at catalyzing rare diseases research. These initiatives fall into two groups: Promoting information sharing; and building multi-disciplinary multi-stakeholder collaborations. Among ORDR's information sharing initiatives are GARD (The Genetics and Rare Diseases Information Center), RaDaR (The Rare Diseases Registries Program) and the NCATS Toolkit for Patient-Focused Therapy Development (Toolkit). Among the collaboration initiatives are the RDCRN (Rare Diseases Clinical Research Network), and the NCATS ORDR support for conferences and workshops. Despite the success of these programs, there remains substantial work to be done to build enhanced collaborations, clinical harmonization and interoperability, and stakeholder engagement so that the recent scientific advances can benefit all patients on the long list of rare diseases waiting for help.

Representation of Women and Minorities in Clinical Trials for New Molecular Entities and Original Therapeutic Biologics Approved by FDA CDER from 2013 to 2015.

BACKGROUND: The U.S. Food and Drug Administration (FDA) has made efforts to encourage adequate assessment of women, racial/ethnic minorities, and geriatric participants in clinical trials through regulations and guidance documents. This study surveyed the demographics of clinical trial participants and the presence of efficacy and safety analyses by sex for new drugs approved between 2013 and 2015 by the FDA Center for Drug Evaluation and Research. METHODS: New drug marketing applications submitted to FDA were surveyed for demographic data (sex, race, ethnicity, and age) and the presence of sex-based analyses for efficacy and safety. The Ratio of the Proportion of women in clinical trials for the indicated disease population relative to the estimated Proportion of women in the disease population (PPR) was calculated for new drug indications. RESULTS: Of the 102 new drugs in this cohort (defined as new molecular entity drugs and original therapeutic biologics), sex was reported for >99.9% of trial participants, and women accounted for 40.4% of these participants. An estimated 77.2% of participants were White, 6.4% were Black/African American, and 29.1% were aged ≥65 years. Sex-based analyses for both efficacy and safety were conducted for 93.1% of applications. PPR was calculated for 82 new drugs for a total of 60 indications, of which 50 indications (83.3%) had a PPR ≥0.80. CONCLUSIONS: Sex data are now collected for almost all study participants, and this study shows appropriate sex participation for most new drugs when estimated disease prevalence by sex (PPR) is considered. Therapeutic area and disease indication are important considerations when assessing the sex of participants because variation occurs depending on the disease under study. Some racial minorities, especially Blacks/African Americans, are still not well represented in most drug development programs and remain an area where improvement is needed.

Investigational New Drug applications: a 1-year pilot study on rates and reasons for clinical hold.

BACKGROUND: The Food and Drug Administration (FDA)'s Center for Drug Evaluation and Research (CDER) receives about 1500 initial Investigational New Drug applications (INDs) per year. In the first 30 days after initial IND submission, FDA conducts a review to determine whether the proposed investigation is safe to proceed, and if not, the IND may be placed on clinical hold. METHODS: A retrospective study of rates and reasons for clinical hold for all initial INDs submitted to CDER in fiscal year (FY) 2013 was performed. INDs were assessed for reasons that led to clinical hold, included chemistry, manufacturing and controls (CMC), animal toxicology or clinical issues. INDs were further categorized by commercial versus research sponsorship, and rare versus common disease indications. All INDs placed on hold were reassessed by whether they remained on hold within the first year following hold imposition. RESULTS: CDER received 1410 initial INDs in FY 2013, of which 125 (8.9%) were placed on hold during the first 30 days after initial submission. Of the INDs placed on hold, more than half became active within the first year after first imposition of hold. CMC reasons were most commonly cited, followed by clinical, then toxicology reasons. There were no substantive differences in rates and reasons for hold between INDs for rare or common disease indications, or between commercial or research INDs. CONCLUSIONS: The vast majority of initial INDs moved forward within 30 days after submission, and for those applications placed on hold, most became active within 1 year. The findings also suggest that many holds for new drug product programs can be avoided by following the available guidelines for investigational product development.

Pre-Investigational New Drug Meetings With the FDA: Evaluation of Meeting Content and Characteristics of Applications for New Drug and Biologic Products.

INTRODUCTION: Prior studies suggested that holding preinvestigational new drug application (PIND) meetings with FDA has a positive effect on clinical development time (CDT). METHODS: New product marketing applications submitted to FDA CDER during fiscal years 2008-2012 were assessed for whether a PIND meeting was held and, if so, a qualitative assessment of meeting content was performed. RESULTS: Discussions contained in the PIND meeting minutes tended to reflect topics appropriate to an early phase of drug development, including chemistry, manufacturing, and controls (CMC) and safety topics (eg, nonclinical and clinical domains). Additionally, FDA commonly provided additional advice most often in the clinical and CMC domains. Applications for which a PIND meeting was held during drug development had shorter CDTs than those that did not. CONCLUSIONS: This analysis showed the importance of early communication with FDA during development, and small companies with limited regulatory experience may gain the greatest benefit from early communication with FDA.

Characteristics of rare disease marketing applications associated with FDA product approvals 2006-2010.

New drug and biologic product marketing applications submitted to FDA's Center for Drug Evaluation and Research (CDER) between 2006 and 2010 were analyzed to identify rare disease application characteristics associated with higher approval rates. The results show that approval rates were similar for rare and common disease applications. Larger company size, prior regulatory experience and priority review designation were associated with higher approval rates. The study findings show that rare disease product development is feasible, and increased interactions between product developers and FDA in early investigational phases can facilitate product development.

Regulatory considerations for developing drugs for rare diseases: orphan designations and early phase clinical trials.

The development of drug and biological products intended to treat rare diseases (Orphan diseases) is one of the fastest growing areas of clinical research, and also one of the most challenging. This article provides an introduction to two important regulatory considerations for Orphan drugs: Orphan status designations and general considerations for the administration of investigational agents in early phase clinical trials. Incentives available to orphan drug developers under the Orphan Drug Act (ODA) and requirements for obtaining an orphan status designation are discussed. An introductory overview of ethical and statutory considerations for investigational drugs, requirements for initiating investigational new drug applications (INDs), and sources of information and advice from the US Food and Drug Administration (FDA) are also described.

Clinical pharmacology as a cornerstone of orphan drug development.

A recent US Food and Drug Administration (FDA) advisory committee meeting highlighted the potential of clinical pharmacology to overcome challenges in orphan drug development.

Accelerating orphan drug development.

Interest in developing drugs for rare diseases has increased substantially in recent years. This article from the US Food and Drug Administration highlights the role of regulators in catalysing further progress in this field.

Therapies for inborn errors of metabolism: what has the orphan drug act delivered?

OBJECTIVE: The 1983 US Orphan Drug Act established a process through which promising therapies are designated as orphan products and, later, with satisfactory safety and efficacy data, receive marketing approval and fiscal incentives. We examined accomplishments in drug development for inborn errors of metabolism (IEMs). METHODS: Food and Drug Administration data were used to identify orphan product designations and approvals for IEMs, and the trends for the past 26 years were summarized. Individual clinical development times (CDTs) from filing investigational new drug application to marketing approval were determined. RESULTS: We examined 1956 orphan product designations from 1983 through 2008 and found 93 (4.8%) for IEMs. Of those, 24 (25.8%) received marketing approval. This proportion of approval was significantly (P = .036) higher than that for non-IEM orphan products (17%). Among the IEM products, disorders of complex molecules received the most designations and approvals (61 and 11, respectively). Among the subgroups, lysosomal storage diseases received the most designations and approvals (43 and 9, respectively), whereas mitochondrial diseases (other than fatty acid oxidation disorders) received 7 designations with no approvals. We then examined the CDTs for the approved IEM products and found a median of 6.4 years (range: 2.6-25.1 years). Biological products had significantly shorter CDTs than drugs (mean: 4.6 vs 11.0 years; P = .003). CONCLUSION: For 26 years, the Orphan Drug Act has generated new therapies for IEMs. Why some IEMs have motivated successful drug development and others have not remains enigmatic; yet the needs of IEM patients without treatment are a certainty.