Overcoming Barriers to Drug Development in Children with CKD.

Like all sick children, children with CKD need access to safe and effective medicines that have been formulated and examined specifically for them. Despite legislation in the United States and the European Union that either mandates or incentivizes programs for children, conducting trials to advance the treatment of children continues to prove to be a challenge for drug developers. This is also the case for drug development in children with CKD, where trials face challenges in recruitment and completion and where there remains a substantial time lag between initial approval of a medicinal product for use in adults and completion of studies that result in the addition of pediatric-specific labeling for the same indication. The Kidney Health Initiative commissioned a workgroup of diverse stakeholders ( https://khi.asn-online.org/projects/project.aspx?ID=61 ), including participants from the Food and Drug Administration and the European Medicines Agency, to think carefully through the challenges in drug development for children with CKD and how to overcome them. This article provides an overview of the regulatory frameworks in the United States and the European Union that govern pediatric drug development, the current landscape of drug development and approval for children with CKD, the challenges in conduct and execution of these drug trials, and the progress that has been made to facilitate drug development for children with CKD.

Recommendations by the European Network of Paediatric Research at the European Medicines Agency (Enpr-EMA) Working Group on preparedness of clinical trials about paediatric medicines process.

Conduct of clinical trials in babies, children and young people is often hindered by issues that could have been foreseen before the trial opened; that is, some clinical trials are often underprepared. In order to identify a good approach to trial preparedness, the European Network of Paediatric Research at the European Medicines Agency formed a working group. The Working Group included representation from regulators, industry, academics, paediatric clinical research networks and parents.The Working Group consulted widely about how to prepare for paediatric clinical trials. The Group's detailed recommendations have been published (https://www.ema.europa.eu/en/documents/other/preparedness-medicines-clinical-trials-paediatrics-recommendations-enpr-ema-working-group-trial_en.pdf).This paper is a summary of the key recommendations including the following: start early, preferably in parallel to designing the medicine's development plan and individual protocols; identify the rationale and clinical need; listen to the perspectives of children and families, and of patient advocacy groups; identify how many people will be eligible for the trial; identify the resources needed, such as clinical facilities (including play therapy) and out-of-pocket expenditure by participants and their families; use all available data to estimate what is possible; present information about preparedness in a structured way; deploy proportionate resources to support the preparation of trials.A well-prepared, well-designed trial is likely to require fewer changes during its course, be run in a shorter time frame and achieve expected objectives.

Evaluation of Juvenile Animal Studies for Pediatric CNS-Targeted Compounds: A Regulatory Perspective.

Central nervous system (CNS)-targeted products are an important category of pediatric pharmaceuticals. In view of the significant postnatal maturation of the CNS, juvenile animal studies (JAS) are performed to support pediatric development of these new medicines. In this project, the design and results of juvenile toxicity studies from 15 drug compounds for the treatment of neurologic or psychiatric conditions were analyzed. Studies were conducted mostly in rats; sometimes in addition in dogs and monkeys. The study design of the pivotal JAS was variable, even for compounds with a similar therapeutic indication. Age of the juvenile animals was not consistently related to the starting age of the intended patient population. Of 15 compounds analyzed, 6 JAS detected more severe toxicities and 6 JAS evidenced novel CNS effects compared to their adult counterparts. The effects of CNS on acoustic startle and learning and memory were observed at high dosages. Reversibility was tested in most cases and revealed some small effects that were retained or only uncovered after termination of treatment. The interpretation of the relevance of these findings was often hampered by the lack of matching end points in the adult studies or inappropriate study designs. Detailed clinical observation and motor activity measures were the most powerful end points to detect juvenile CNS effects. The need for more detailed behavioral examinations in JAS, for example, on learning and memory, should, therefore, be decided upon on a case-by-case basis, based on specific concerns in order to avoid overloading the studies.

Enabling Development of Paediatric Medicines in Europe: 10 Years of the EU Paediatric Regulation.

The year 2017 marks the tenth anniversary of entry into force of the Paediatric Regulation in the European Union (EU). This law aimed to stimulate the development of paediatric medicines and provide more information on their use, as a response to the lack of evidence and approval of medicines for children. The European Medicines Agency (EMA) has had a central role in the implementation of the Regulation. Pharmaceutical companies need to submit a paediatric investigation plan (PIP) to the EMA's Paediatric Committee (PDCO) for every new medicine, unless an exemption (waiver) is granted. The plans, which describe the development of drugs for children, must be agreed well in advance of the request for marketing authorization of the medicine. Deferrals of studies can be granted to allow approval in adults before the completion of paediatric studies. Between January 2007 and December 2016, a total of 273 new medicines and 43 additional pharmaceutical forms appropriate for use in children were authorized in the EU, and 950 PIPs were agreed by the EMA. In addition, 486 waivers of the development of a medicine in one or more medical conditions were agreed. The Paediatric Regulation has had a very positive impact on paediatric drug development, as exemplified by a comparison of two periods of 3 years before and after entry into force of the Regulation. We conclude that the Regulation has resulted in more medicines for children and more information on the pediatric use of medicines in the EU being available to clinicians.

A Comparative Review of Waivers Granted in Pediatric Drug Development by FDA and EMA from 2007-2013.

BACKGROUND: The European Union and the United States have different legal frameworks in place for pediatric drug development, which can potentially lead to different pediatric research requirements for the pharmaceutical industry. This manuscript compares pediatric clinical trial waivers granted by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA). METHODS: This is a retrospective review comparing EMA's Paediatric Committee (PDCO) decisions with FDA's Pediatric Review Committee (PeRC) recommendations for all product-specific pediatric full waiver applications submitted to EMA from January 2007 through December 2013. Using baseline data from EMA, we matched product-specific waivers with their FDA equivalents during the study period. RESULTS: For single active substance products, PDCO and PeRC adopted similar opinions in 42 of 49 indications (86%). For fixed-dose combinations, PDCO and PeRC adopted similar opinions in 24 of 31 indications (77%). CONCLUSION: Despite the different legal frameworks, criteria, and processes of determination, the waiver decisions of the 2 agencies were similar in the majority of cases.

Quantification of microvessels in canine lymph nodes.

Quantification of microvessels in tumors is mostly based on counts of vessel profiles in tumor hot spots. Drawbacks of this method include low reproducibility and large interobserver variance, mainly as a result of individual differences in sampling of image fields for analysis. Our aim was to test an unbiased method for quantifying microvessels in healthy and tumorous lymph nodes of dogs. The endothelium of blood vessels was detected in paraffin sections by a combination of immunohistochemistry (von Willebrand factor) and lectin histochemistry (wheat germ agglutinin) in comparison with detection of basal laminae by laminin immunohistochemistry or silver impregnation. Systematic uniform random sampling of 50 image fields was performed during photo-documentation. An unbiased counting frame (area 113,600 microm(2)) was applied to each micrograph. The total area sampled from each node was 5.68 mm(2). Vessel profiles were counted according to stereological counting rules. Inter- and intraobserver variabilities were tested. The application of systematic uniform random sampling was compared with the counting of vessel profiles in hot spots. The unbiased estimate of the number of vessel profiles per unit area ranged from 100.5 +/- 44.0/mm(2) to 442.6 +/- 102.5/mm(2) in contrast to 264 +/- 72.2/mm(2) to 771.0 +/- 108.2/mm(2) in hot spots. The advantage of using systematic uniform random sampling is its reproducibility, with reasonable interobserver and low intraobserver variance. This method also allows for the possibility of using archival material, because staining quality is not limiting as it is for image analysis, and artifacts can easily be excluded. However, this method is comparatively time-consuming.

Articular cartilage in the knee joint of the African elephant, Loxodonta africana, Blumenbach 1797.

Knee joints of one adult and three juvenile African elephants were dissected. The specific features of the articular cartilage with particular reference to matrix components were studied by light and electron microscopy and immunohistochemistry. The elephant knee joint cartilage contains an unusually low concentration of proteoglycans resulting in rather eosinophilic staining properties of the matrix. The very thick collagen fibers of the cartilage possibly represent collagen I. Except for the different thickness of cartilage at the weight-bearing surfaces of femur (approximately 6.7 mm) and tibia (approximately 11.2 mm) in juvenile elephants, light and electron microscopy did not reveal distinct topographical differences in cartilage structure, perhaps because of the high congruency of the articulating surfaces and resulting uniform load distribution in the knee. The number of cell profiles per section area of both femoral (approximately 950 cell profiles/mm(2)) and tibial cartilage (approximately 898 cell profiles/mm(2)) was low, indicating excessive matrix production by the chondrocytes during cartilage development. These unique properties could be a result of the enormous compressive load resting on the elephant knee. Maintenance of the equilibrium between biological function and resistance to compression seems to be crucial in the elephant knee joint cartilage. Any disturbance that interferes with this equilibrium appears to lead to arthrotic alterations, as particularly seen in captive elephants.

Microvessel density in normal lymph nodes and lymphomas of dogs and their correlation with vascular endothelial growth factor expression.

Microvessel density is a frequently used parameter of angiogenesis, which is a complex multistep process necessary for tumor progression. The aim of this study was to compare the microvessel density of normal lymph node biopsies with those diagnosed with lymphoma in dogs. Furthermore, we sought to determine if there was any correlation between microvessel density and vascular endothelial growth factor expression in canine lymphoma, representing a potential target for anti-angiogenic therapy. Combined immunohistochemistry (von Willebrand factor) and lectin histochemistry was used to highlight microvessels in 40 untreated canine lymphomas and 14 normal lymph nodes. To evaluate microvessel density, the number of profiles of blood vessels per unit area was calculated. Fifty image fields (a total area of 5.68 mm(2)) were sampled for each specimen in a systematic random, way. We found a significant difference between the microvessel densities (MVD) of normal and neoplastic lymph nodes (177+/-35 versus 241+/-72 microvessel profiles/mm(2)). Classifying lymphoma samples according to the working formulation and the Kiel classification system revealed no significant differences in MVD between different grade malignancies. Immunohistochemical demonstration of the proangiogenic protein vascular endothelial growth factor showed expression in 60% of canine lymphomas, although there was no correlation between microvessel density and vascular endothelial growth factor expression. As an increase in tumor angiogenesis was observed in lymphoma samples compared to normal canine lymph node tissue, additional anti-angiogenic therapy, besides conventional chemotherapy as a lymphoma treatment may be effective. The optimal target among many pro-angiogenic factors has yet to be elucidated.

Renaut bodies in nerves of the trunk of the African elephant, Loxodonta africana.

Renaut bodies are loosely textured, cell-sparse structures in the subperineurial space of peripheral nerves, frequently found at sites of nerve entrapment. The trunk of the elephant is a mobile, richly innervated organ, which serves for food gathering, object grasping and as a tactile organ. These functions of the trunk lead to distortion and mechanical compression of its nerves, which can therefore be expected to contain numerous Renaut bodies. Samples of the trunk wall of an adult African elephant (Loxodonta africana) were examined histologically using conventional staining methods, immunohistochemistry, and lectin histochemistry. Architecture of nerve plexuses and occurrence of Renaut bodies in the elephant trunk were compared with those in tissues surrounding the nasal vestibule of the pig. Prominent nerve plexuses were found in all layers of the elephant trunk. Almost all (81%) nerve profiles contained Renaut bodies, a basophilic, discrete subperineurial layer resembling cushions around the nerve core. In contrast, Renaut bodies were seen in only 15% of nerve profiles in the porcine nasal vestibule. Within Renaut bodies, fusiform fibroblasts and round, ruff-like cells were placed into a matrix of acidic glycosaminoglycans with delicate collagen and very few reticular fibers. The turgor of this matrix is thought to protect nerves against compression and shearing strain. Renaut bodies are readily stained with alcian blue (pH 2.5) favorably in combination with immunohistochemical markers of nerve fibers. They should be regarded as a physiological response to repeated mechanical insults and are distinct from pathological alterations. alterations.