A roadmap toward clinical translation of genetically-modified stem cells for treatment of HIV

Genetic Engineering of Therapeutic Cells with the Sodium Iodide Symporter (NIS) to Enable Noninvasive In Vivo Therapy Tracking

Noninvasive long-term imaging of therapeutic cells in preclinical models can be achieved through introducing a reporter gene into the cells of interest. Despite important recent developments such as gene editing, cell engineering based on lentiviruses remains a mainstream tool for gene transfer applicable to a variety of different cell types.In this chapter, we describe how to use lentivirus-based genetic engineering to render different candidate cell therapies in vivo traceable by radionuclide imaging. We illustrate this reporter gene technology using the sodium iodide symporter (NIS), which is compatible with both positron emission tomography (PET) and single-photon emission computed tomography (SPECT). For preclinical experimentation, we fused NIS with a suitable fluorescent protein such as monomeric GFP or RFP to streamline cell line generation and downstream analyses of ex vivo tissue samples. We present protocols for reporter gene engineering of human cardiac progenitor cells, regulatory T cells, and effector T cells as well as for the characterization experiments required to validate NIS-fluorescent protein reporter function in these candidate therapeutic cells.

New era of personalized medicine: Advanced therapy medicinal products in Europe

Advanced therapy medicinal products are human medical therapies based on genes, cells, or tissues, and due to their characteristics, they offer new innovative opportunities for the treatment of diseases and injuries, especially for diseases beyond the reach of traditional approaches. These therapies are at the forefront of innovation and have historically been very controversial, although in the last decade they have gained prominence while the number of new advanced therapies has increased every year. In this regard, despite the controversy they may generate, they are expected to dominate the market in the coming decades. Technologies based on advanced therapies are the present and future of medicine and bring us closer to the long-awaited precision medicine. Here we review the field as it stands today, with a focus on the molecular mechanisms that guided the different advanced therapies approved by the European Medicines Agency, their current status, and their legal approval.

Unproven stem cell interventions: A global public health problem requiring global deliberation

The unproven stem cell intervention (SCI) industry is a global health problem. Despite efforts of some nations, the industry continues to flourish. In this paper, we call for a global approach and the establishment of a World Health Organization (WHO) Expert Advisory Committee on Regenerative Medicine to tackle this issue and provide guidance. The WHO committee can harmonize national regulations; promote regulatory approaches responsive to unmet patient needs; and formulate an education campaign against misinformation. Fostering an international dialog and developing recommendations that can be adopted by member states would effectively address the global market of unproven SCIs.

Enabling MedTech Translation in Academia: Redefining Value Proposition with Updated Regulations

Academic institutions are becoming more focused on translating new technologies for clinical applications. A transition from "bench to bedside" is often described to take basic research concepts and methods to develop a therapeutic or diagnostic solution with proven evidence of efficacy at the clinical level while also fulfilling regulatory requirements. The regulatory environment is evolving in Europe with transition and grace periods for the full enforcement of the Medical Device Regulation 2017/745 (MDR), replacing the Medical Device Directive 93/42/EEC (MDD). These new guidelines increase demands for scientific, technical, and clinical data with reduced capacity in regulatory bodies creating uncertainty in future product certification. Academic translational activities will be uniquely affected by this new legislation. The barriers and threats to successful translation in academia can be overcome by strong clinical partnerships, close-industrial collaborations, and entrepreneurial programs, enabling continued product development to overcome regulatory hurdles, reassuring their foothold of medical device development.

Non-invasive Reporter Gene Imaging of Cell Therapies, including T Cells and Stem Cells

Cell therapies represent a rapidly emerging class of new therapeutics. They are intended and developed for the treatment of some of the most prevalent human diseases, including cancer, diabetes, and for regenerative medicine. Currently, they are largely developed without precise assessment of their in vivo distribution, efficacy, or survival either clinically or preclinically. However, it would be highly beneficial for both preclinical cell therapy development and subsequent clinical use to assess these parameters in situ to enable enhancements in efficacy, applicability, and safety. Molecular imaging can be exploited to track cells non-invasively on the whole-body level and can enable monitoring for prolonged periods in a manner compatible with rapidly expanding cell types. In this review, we explain how in vivo imaging can aid the development and clinical translation of cell-based therapeutics. We describe the underlying principles governing non-invasive in vivo long-term cell tracking in the preclinical and clinical settings, including available imaging technologies, reporter genes, and imaging agents as well as pitfalls related to experimental design. Our emphasis is on adoptively transferred T cell and stem cell therapies.

A few ethical issues in translational research for gene and cell therapy

Background

Although translational research for drug development can provide patients with valuable therapeutic resources it is not without risk, especially in the early-phase trials that present the highest degree of uncertainty. With the extraordinary evolution of biomedical technologies, a growing number of innovative products based on human cells and gene therapy are being tested and used as drugs. Their use on humans poses several challenges.

Methods

In this work, we discuss some ethical issues related to gene and cell therapies translational research. We focus on early-phase studies analysing the regulatory approach of Europe and the United States. We report the current recommendations and guidelines of international scientific societies and European and American regulatory authorities.

Results

The peculiarity of human cell- or tissue-based products and gene therapy has required the development of specific regulatory tools that must be continually updated in line with the progress of the research. The ethics of translational research for these products also requires further considerations, particularly with respect to the specificity of the associated risk profiles.

Conclusions

An integrated ethical approach that aims for transparency and regulation of development processes, the support of independent judgment in clinical trials and the elimination of unregulated and uncontrolled grey areas of action are necessary to move gene and cell therapy forward.

Concise Review: A Comprehensive Analysis of Reported Adverse Events in Patients Receiving Unproven Stem Cell-Based Interventions

The promise of stem cell (SC) therapies to restore functions of damaged tissues and organs brings enormous hope to patients, their families, loved ones, and caregivers. However, limits may exist for which indications SC therapies might be useful, efficacious, and safe. Applications of innovative therapies within regulatory boundaries and within the framework of controlled clinical trials are the norm in the scientific and medical community; such a system minimizes patient risk by setting a clear and acceptable safety and efficacy profile for new therapeutics before marketing authorization. This careful clinical validation approach often takes time, which patients suffering from terminal or debilitating diseases do not have. Not validated, unproven stem cell interventions (SCI) that promise a working treatment or cure for severe diseases have therefore found their way into the patient community, and providers of such treatments often take advantage of the public's willingness to pay large amounts of money for the misguided hope of a reliable recovery from their illnesses. We conducted a review of scientific publications, clinical case reports, and mass media publications to assess the reported cases and safety incidents associated with unproven SCI. The review also analyzes the main factors that were identified as contributing to the emergence and global rise of the “stem cell tourism” phenomenon. stemcellstranslationalmedicine2018;1–10

Regulatory and Scientific Advancements in Gene Therapy: State-of-the-Art of Clinical Applications and of the Supporting European Regulatory Framework

Advanced therapy medicinal products (ATMPs) have a massive potential to address existing unmet medical needs. Specifically, gene therapy medicinal products (GTMPs) may potentially provide cure for several genetic diseases. In Europe, the ATMP regulation was fully implemented in 2009 and, at this point, the Committee for Advanced Therapies was created as a dedicated group of specialists to evaluate medicinal products requiring specific expertise in this area. To date, there are three authorized GTMPs, and the first one was approved in 2012. Broad research has been conducted in this field over the last few decades and different clinical applications are being investigated worldwide, using different strategies that range from direct gene replacement or addition to more complex pathways such as specific gene editing or RNA targeting. Important safety risks, limited efficacy, manufacturing hurdles, or ethical conflicts may represent challenges in the success of a candidate GTMP. During the development process, it is fundamental to take such aspects into account and establish overcoming strategies. This article reviews the current European legal framework of ATMPs, provides an overview of the clinical applications for approved and investigational GTMPs, and discusses critical challenges in the development of GTMPs.

Overcoming Challenges Facing Advanced Therapies in the EU Market

While advanced therapy medicinal products offer great clinical promise, most EU-approved products have not achieved satisfactory commercial performance. Here we highlight a number of issues that prevent current products from obtaining commercial success and pitfalls that developers must overcome in future product development.

Strategies for Derisking Translational Processes for Biomedical Technologies

Inefficient translational processes for technology-oriented biomedical research have led to some prominent and frequent failures in the development of many leading drug candidates, several designated investigational drugs, and some medical devices, as well as documented patient harm and postmarket product withdrawals. Derisking this process, particularly in the early stages, should increase translational efficiency and streamline resource utilization, especially in an academic setting. In this opinion article, we identify a 12-step guideline for reducing risks typically associated with translating medical technologies as they move toward prototypes, preclinical proof of concept, and possible clinical testing. Integrating the described 12-step process should prove valuable for improving how early-stage academic biomedical concepts are cultivated, culled, and manicured toward intended clinical applications.

Putting a price tag on novel autologous cellular therapies

Cell therapies, especially autologous therapies, pose significant challenges to researchers who wish to move from small, probably academic, methods of manufacture to full commercial scale. There is a dearth of reliable information about the costs of operation, and this makes it difficult to predict with confidence the investment needed to translate the innovations to the clinic, other than as small-scale, clinician-led prescriptions. Here, we provide an example of the results of a cost model that takes into account the fixed and variable costs of manufacture of one such therapy. We also highlight the different factors that influence the product final pricing strategy. Our findings illustrate the need for cooperative and collective action by the research community in pre-competitive research to generate the operational models that are much needed to increase confidence in process development for these advanced products.

Gene therapy: a possible future standard for HIV care

Despite undeniable accomplishments in developing cell and gene therapeutic strategies to combat HIV infection, key social, economic, and policy-related challenges still need to be overcome for any future commercialization efforts of these novel therapies to be successful. Here, we address these challenges and structure a framework for eradicating HIV/AIDS using gene therapy.

Combinatorial hematopoietic stem cell transplantation and vaccination reduces viral pathogenesis following SHIV89.6P-challenge

Development of curative approaches for HIV-1 infected patients requires novel approaches aimed at eliminating viral reservoirs and replacing potential target cells with infection-resistant immune cell populations. We have previously shown that autologous transplantation of genetically modified hematopoietic stem cells (HSCs) with lentiviral vectors encoding the mC46-fusion inhibitor results in a significant reduction in viral pathogenesis following challenge with the highly pathogenic dual tropic, SHIV89.6P strain. In this study, we used a combinatorial approach in which following engraftment of genetically modified HSCs, pigtailed macaques were vaccinated with a previously developed vaccinia-based vaccine expressing SIV-Gag, Pol. Using this dual therapy approach, lower viremia was detected in both the acute and chronic phase of disease with levels reaching near the lower limits of detection. In comparison with macaques receiving HSCT only, the combination approach resulted in a further log decrease in plasma viremia. Similar to our previous studies, positive selection of all CD4(+) T-cell subsets was observed; however, higher gene-modified CD4(+) T-cell levels were observed during the chronic phase when vaccination was included suggesting that combining vaccination with HSCT may lower the necessary threshold for achieving viremic control.

Use of the CRISPR/Cas9 system as an intracellular defense against HIV-1 infection in human cells

To combat hostile viruses, bacteria and archaea have evolved a unique antiviral defense system composed of clustered regularly interspaced short palindromic repeats (CRISPRs), together with CRISPR-associated genes (Cas). The CRISPR/Cas9 system develops an adaptive immune resistance to foreign plasmids and viruses by creating site-specific DNA double-stranded breaks (DSBs). Here we adapt the CRISPR/Cas9 system to human cells for intracellular defense against foreign DNA and viruses. Using HIV-1 infection as a model, our results demonstrate that the CRISPR/Cas9 system disrupts latently integrated viral genome and provides long-term adaptive defense against new viral infection, expression and replication in human cells. We show that engineered human-induced pluripotent stem cells stably expressing HIV-targeted CRISPR/Cas9 can be efficiently differentiated into HIV reservoir cell types and maintain their resistance to HIV-1 challenge. These results unveil the potential of the CRISPR/Cas9 system as a new therapeutic strategy against viral infections.

Bioinformatics and HIV latency

Despite effective treatment, HIV is not completely eliminated from the infected organism because of the existence of viral reservoirs. A major reservoir consists of infected resting CD4+ T cells, mostly of memory type, that persist over time due to the stable proviral insertion and a long cellular lifespan. Resting cells do not produce viral particles and are protected from viral-induced cytotoxicity or immune killing. However, these latently infected cells can be reactivated by stochastic events or by external stimuli. The present review focuses on novel genome-wide technologies applied to the study of integration, transcriptome, and proteome characteristics and their recent contribution to the understanding of HIV latency.