From the Integrity of Potency Assays to Safe Clinical Intervention: Legal Perspectives.

Potency assays associated with the efficacy of investigational pharmaceutical products are one of the critical quality attributes that need to be carefully monitored during advanced therapy medicinal product (ATMP) development projects. Ensuring integrity of relevant potency assays for stem cell-based ATMPs is of paramount importance for safety and efficacy of clinical interventions. Yet, due to the complex and heterogeneous nature of stem cell-based ATMPs, creation of an appropriate set of potency assays is associated with a number of specific challenges ranging from intrinsic and operational to legal and regulatory ones. This chapter provides an overview of the EU regulatory landscape for advanced therapies, highlighting important aspects that need to be taken into consideration when preparing a strategic plan to meet the EU regulatory requirements.

Polyclonal Regulatory T Cell Manufacturing Under cGMP: A Decade of Experience.

We report on manufacturing outcomes for 41 autologous polyclonal regulatory T cell (PolyTreg) products for 7 different Phase 1 clinical trials over a 10-year period (2011-2020). Data on patient characteristics, manufacturing parameters, and manufacturing outcomes were collected from manufacturing batch records and entered into a secure database. Overall, 88% (36/41) of PolyTreg products met release criteria and 83% (34/41) of products were successfully infused into patients. Of the 7 not infused, 5 failed release criteria, and 2 were not infused because the patient became ineligible due to a change in clinical status. The median fold expansion over the 14-day manufacturing process was 434.8 -fold (range 29.8-2,232), resulting in a median post-expansion cell count of 1,841 x 106 (range 56.9-16,179 x 106). The main correlate of post-expansion cell number was starting cell number, which positively correlates with absolute circulating Treg cell count. Other parameters, including date of PolyTreg production, patient sex, and patient age did not significantly correlate with fold expansion of Treg during product manufacturing. In conclusion, PolyTreg manufacturing outcomes are consistent across trials and dates of production.

Clinical experience of coronavirus disease 2019 in hematopoietic cell transplant and chimeric antigen receptor T-cell recipients.

PURPOSE OF REVIEW: To discuss the clinical experience of coronavirus disease 2019 (COVID-19) in hematopoietic cell transplant and chimeric antigen receptor T-cell therapy recipients over the past year and to identify key knowledge gaps for future research. RECENT FINDINGS: Immunocompromised individuals and those with chronic health conditions are especially susceptible to infections, which have had a disproportionate impact on health outcomes during the COVID-19 pandemic. Several studies have evaluated the clinical characteristics and outcomes of transplant and cellular therapy (TCT) recipients who developed COVID-19. Age, sex, comorbid conditions, and social determinants of health are important predictors of the risk of severe acute respiratory syndrome coronavirus 2 infection and of the eventual severity of the disease. Various treatment approaches have been investigated over the last year. The paradigm of management strategies continues to evolve as more experience is accumulated. SUMMARY: In this review, we summarize some important findings as they relate to the clinical characteristics of TCT recipients who develop COVID-19. We also discuss some treatment approaches that are currently recommended and opine on vaccination in this population.

ISSCR's Guidelines for Stem Cell Research and Clinical Translation: Supporting development of safe and efficacious stem cell-based interventions.

The ISSCR's revised Guidelines for Stem Cell Research and Clinical Translation reflect the organization's commitment to opposing premature commercialization of stem cell-based interventions and supporting the development of products that meet stringent ethical, scientific, and regulatory standards. The Guidelines contain five important new recommendations concerning clinical translation of stem cell products.

Reflection on the enactment and impact of safety laws for regenerative medicine in Japan.

Japan's Act on the Safety of Regenerative Medicine (ASRM) created an innovative regulatory framework intended to safely promote the clinical development of stem cell-based interventions (SCBIs) while subjecting commercialized unproven SCBIs to greater scrutiny and accountability. This article reviews ASRM's origins, explains its unprecedented scope, and assesses how it envisions the regulation of SCBIs. This analysis is used to highlight three key insights that are pertinent to the current revision of the ASRM: clarifying how the concept of safety should be defined and assessed in research and clinical care settings; revisiting risk criteria for review of SCBIs; and taking stronger measures to support the transition from unproven interventions to evidence-based therapies. Finally, the article reflects on lessons drawn from Japanese experiences in dealing with unproven SCBIs for international endeavors to regulate SCBIs.

Fit-For-All iPSC-Derived Cell Therapies and Their Evaluation in Humanized Mice With NK Cell Immunity.

Human induced pluripotent stem cells (iPSCs) can be limitlessly expanded and differentiated into almost all cell types. Moreover, they are amenable to gene manipulation and, because they are established from somatic cells, can be established from essentially any person. Based on these characteristics, iPSCs have been extensively studied as cell sources for tissue grafts, blood transfusions and cancer immunotherapies, and related clinical trials have started. From an immune-matching perspective, autologous iPSCs are perfectly compatible in principle, but also require a prolonged time for reaching the final products, have high cost, and person-to-person variation hindering their common use. Therefore, certified iPSCs with reduced immunogenicity are expected to become off-the-shelf sources, such as those made from human leukocyte antigen (HLA)-homozygous individuals or genetically modified for HLA depletion. Preclinical tests using immunodeficient mice reconstituted with a human immune system (HIS) serve as an important tool to assess the human alloresponse against iPSC-derived cells. Especially, HIS mice reconstituted with not only human T cells but also human natural killer (NK) cells are considered crucial. NK cells attack so-called "missing self" cells that do not express self HLA class I, which include HLA-homozygous cells that express only one allele type and HLA-depleted cells. However, conventional HIS mice lack enough reconstituted human NK cells for these tests. Several measures have been developed to overcome this issue including the administration of cytokines that enhance NK cell expansion, such as IL-2 and IL-15, the administration of vectors that express those cytokines, and genetic manipulation to express the cytokines or to enhance the reconstitution of human myeloid cells that express IL15R-alpha. Using such HIS mice with enhanced human NK cell reconstitution, alloresponses against HLA-homozygous and HLA-depleted cells have been studied. However, most studies used HLA-downregulated tumor cells as the target cells and tested in vitro after purifying human cells from HIS mice. In this review, we give an overview of the current state of iPSCs in cell therapies, strategies to lessen their immunogenic potential, and then expound on the development of HIS mice with reconstituted NK cells, followed by their utilization in evaluating future universal HLA-engineered iPSC-derived cells.

Immune Monitoring for Advanced Cell Therapy Trials in Transplantation: Which Assays and When?

A number of immune regulatory cellular therapies, including regulatory T cells and mesenchymal stromal cells, have emerged as novel alternative therapies for the control of transplant alloresponses. Clinical studies have demonstrated their feasibility and safety, however developing our understanding of the impact of cellular therapeutics in vivo requires advanced immune monitoring strategies. To accurately monitor the immune response, a combination of complementary methods is required to measure the cellular and molecular phenotype as well as the function of cells involved. In this review we focus on the current immune monitoring strategies and discuss which methods may be utilized in the future.

Quality Standards of Stem Cell Sources for Clinical Treatment of Neurodegenerative Diseases.

A large number of experimental and clinical studies have shown that cell transplantation has therapeutic effects for PD, AD and other neurodegenerative diseases or damages. Good Manufacturing Practice (GMP) guidance must be defined to produce clinical-grade cells for transplantation to the patients. Standardized quality and clinical preparation procedures of the transplanted cells will ensure the therapeutic efficacy and reduce the side-effect risk of cell therapy. Here we review the cell quality standards governing the clinical transplantation of stem cells for neurodegenerative diseases to clinical practitioners. These quality standards include cell quality control, minimal suggested cell doses for undergoing cell transplantation, documentation of procedure and therapy, safety evaluation, efficacy evaluation, policy of repeated treatments, not charging the patients for unproven therapies, basic principles of cell therapy, and publishing responsibility.

Considerations on chemistry, manufacturing, and control of stem cell products for Investigational New Drug application in China.

Tremendous progress has been made in recent years to produce functional cells for cell therapy products. Hundreds of clinical trials of stem cell products (SCPs) have shown promising therapeutic potential worldwide, including the products derived from human pluripotent stem cells (hPSCs), adult stem cells and mesenchymal stem cells (MSC). Before starting a clinical trial, comprehensive chemistry, manufacturing and control (CMC) study is required to assure the safety and quality consistency of SCPs. The heterogeneity of stem cell products arises from the variability in the donor tissues, isolation of cells and differentiation processes, and appropriate testing approaches are needed to characterize and release SCPs. Here we summarize the regulatory considerations of CMC study in Investigational New Drug (IND) application of SCPs in China based on the current knowledge, and they will be updated in the future with the advance of stem cell biology and regulatory science.

The environmental risk assessment of cell-processing facilities for cell therapy in a Japanese academic institution.

Cell therapy is a promising treatment. One of the key aspects of cell processing products is ensuring sterility of cell-processing facilities (CPFs). The objective of this study was to assess the environmental risk factors inside and outside CPFs. We monitored the temperature, humidity, particle number, colony number of microorganisms, bacteria, fungi, and harmful insects in and around our CPF monthly over one year. The temperature in the CPF was constant but the humidity fluctuated depending on the humidity outside. The particle number correlated with the number of entries to the room. Except for winter, colonies of microorganisms and harmful insects were detected depending on the cleanliness of the room. Seven bacterial and two fungal species were identified by PCR analyses. Psocoptera and Acari each accounted for 41% of the total trapped insects. These results provide useful data for taking the appropriate steps to keep entire CPFs clean.

Understanding voluntariness of consent in first-in-human cell therapy trials.

Consensus about contents of voluntariness in informed consent is lacking. Core criteria for voluntary consent are needed to ensure voluntariness. This article outlines the multidimensionality of voluntariness and identifies what could reduce voluntariness, especially in first-in-human clinical trials involving cell therapies. In such trials, truly voluntary consent is especially important because: such trials may involve risk of serious harm, while in case of some diseases, eligible patients often have potentially effective therapeutic alternatives; patients considering participation in high-risk first-in-human trials may feel more desperate and some may be dependent on their caregivers, including those in the family; implanted cells cannot be taken out of the patient's body if the patient wants to withdraw.

Effects of nicotine on the translation of stem cell therapy.

Although stem cell therapy has tremendous therapeutic potential, clinical translation of stem cell therapy has yet to be fully realized. Recently, patient comorbidities and lifestyle choices have emerged to be important factors in the efficacy of stem cell therapy. Tobacco usage is an important risk factor for numerous diseases, and nicotine exposure specifically has become increasing more prevalent with the rising use of electronic cigarettes. This review describes the effects of nicotine exposure on the function of various stem cells. We place emphasis on the differential effects of nicotine exposure in vitro and as well as in preclinical models. Further research on the effects of nicotine on stem cells will deepen our understanding of how lifestyle choices can impact the outcome of stem cell therapies.

Improved harmonization of critical characterization assays across cell therapies.

The field of cell therapy has blossomed, providing exciting new options for treating a variety of diseases. While few cell therapy products have US FDA approval, there are thousands of cell treatments at various stages of development, pointing to a potential revolutionary shift in patient care. The expanding number and nature of cellular therapies necessitate greater standardization. Several international organizations are collaborating to pursue some level of global standardization, especially concerning cell banking. However, less harmonization surrounds assays used for critical quality characterization including: identity, purity, safety and potency. Frequently, there is divergence regarding the terms describing the characterization assays across regulatory authorities and guidances. This review summarizes the critical quality assays currently used for different categories of cell therapies. Areas of harmonization and an absence of standardization are highlighted. We propose potential solutions to facilitate harmonization of critical quality characterization assays and the language used to describe them.

Genetically Modified T-Cell Therapy for Osteosarcoma: Into the Roaring 2020s.

T-cell immunotherapy may offer an approach to improve outcomes for patients with osteosarcoma who fail current therapies. In addition, it has the potential to reduce treatment-related complications for all patients. Generating tumor-specific T cells with conventional antigen-presenting cells ex vivo is time-consuming and often results in T-cell products with a low frequency of tumor-specific T cells. Furthermore, the generated T cells remain sensitive to the immunosuppressive tumor microenvironment. Genetic modification of T cells is one strategy to overcome these limitations. For example, T cells can be genetically modified to render them antigen specific, resistant to inhibitory factors, or increase their ability to home to tumor sites. Most genetic modification strategies have only been evaluated in preclinical models; however, early clinical phase trials are in progress. In this chapter, we will review the current status of gene-modified T-cell therapy with special focus on osteosarcoma, highlighting potential antigenic targets, preclinical and clinical studies, and strategies to improve current T-cell therapy approaches.

Adoption of Regulations for Cell Therapy Development: Linkage Between Taiwan and Japan.

Although cell-based therapy has become a promising treatment, its practice and evaluation process remain unstandardized. Therefore, Japan initiated a dual-track regulatory framework for cell-based therapy aiming to promote and regulate the therapies to ensure that patients can access safe and effective treatments. Influenced by such pathway, Taiwan adopted the framework and initiated its own cell-based therapy regulation in 2018. This paper discusses how Japan has influenced Taiwan in developing regulations for cell-based therapy.

Regulatory oversight of cell therapy in China: Government's efforts in patient access and therapeutic innovation.

In recent years, remarkable progress has been made in the fundamental research and on clinical development of cell therapy. Although China has launched a series of regulations to establish a proper regulatory framework that facilitates the development of cell therapy products, the regulatory framework has not been able to meet the country's regulatory requirements. This article introduced the development of regulation and current regulatory pathways for cell therapy in China and identified the main challenges in clinical studies. China has recently tightened its policy on cell therapy clinical studies after medical chaos occurred in the area of cell therapy over the past few years. Currently the regulatory jurisdiction between NMPA and NHC are not very clear, especially for clinical somatic cell research, further efforts are necessary to establish a legislative system with a clear and functional regulatory framework for cell therapy.

Mesenchymal Stem Cell-Derived Exosomes Improve Functional Recovery in Rats After Traumatic Brain Injury: A Dose-Response and Therapeutic Window Study.

Background. Mesenchymal stem cell (MSC)-derived exosomes play a critical role in regenerative medicine. Objective. To determine the dose- and time-dependent efficacy of exosomes for treatment of traumatic brain injury (TBI). Methods. Male rats were subjected to a unilateral moderate cortical contusion. In the dose-response study, animals received a single intravenous injection of exosomes (50, 100, 200 µg per rat) or vehicle, with treatment initiated at 1 day after injury. In the therapeutic window study, animals received a single intravenous injection of 100 µg exosomes or vehicle starting at 1, 4, or 7 days after injury. Neurological functional tests were performed weekly after TBI for 5 weeks. Spatial learning was measured on days 31 to 35 after TBI using the Morris water maze test. Results. Compared with the vehicle, regardless of the dose and delay in treatment, exosome treatment significantly improved sensorimotor and cognitive function, reduced hippocampal neuronal cell loss, promoted angiogenesis and neurogenesis, and reduced neuroinflammation. Exosome treatment at 100 µg per rat exhibited a significant therapeutic effect compared with the 50- or 200-µg exosome groups. The time-dependent exosome treatment data demonstrated that exosome treatment starting at 1 day post-TBI provided a significantly greater improvement in functional and histological outcomes than exosome treatments at the other 2 delayed treatments. Conclusions. These results indicate that exosomes have a wide range of effective doses for treatment of TBI with a therapeutic window of at least 7 days postinjury. Exosomes may provide a novel therapeutic intervention in TBI.

Australian regulation of autologous human cell and tissue products: implications for commercial stem cell clinics.

In 2018, Australia's Therapeutic Goods Administration introduced regulatory reforms that set stricter criteria around the regulation of products derived from a patient's own cells and tissues, posing significant implications for clinics offering stem cell treatments. We review the regulatory framework and discuss its potential commercial implications, including the ambiguities that may arise from it in practice, as well as the likely impact it will have on product development and advertising practices in the future.