Stem Cell Research and Development in the UK

Transcription

1 Stem cell infrastructure report June 2008

2 Contents 2 Executive summary 3 1 Purpose of review 4 2 The UK and stem cell research 4 3 MRC stem cell research portfolio Research grant funding Capacity building Infrastructural investment Strategic initiatives 4 4 State of the science sources of stem cells 5 i) Adult stem cells 5 ii) Fetal stem cells 5 iii) Embryonic stem cells (hescs) 5 iv) Endogenous stem cells 5 v) Somatic cell nuclear transfer (SCNT) 5 vi) Induced pluripotent stem cells (ips cells) supply of stem cells 6 i) Governance of hesc lines 6 ii) UK Stem Cell Bank 6 iii) Other sources (international) therapeutic development 7 i) Background 7 ii) Cardiac disease 7 iii) Diabetes type 1 8 iv) Neurodegenerative disease requirements for basic, translational and clinical research 8 i) Drug development 9 ii) Disease modelling 9 5 regulation eu Cells and Tissue Directive (2004/23/EC) UK Regulation 9 6 Recommendations of the Expert Group 10 Annex: Methods used to conduct review 12 References: 14

3 Executive summary The UK is a world leader in stem cell research, due to its strengths in stem cell and developmental biology and the permissive but strictly controlled regulatory environment that both encourages ethical research and provides reassurance to the general public. This review was undertaken by an MRC Expert Group who assessed the strategic requirements for ensuring the UK remains at the forefront of stem cell research, focussing on the infrastructural support that would be required to promote the development of stem cell therapies and platform technologies over the next decade. The Group made the following recommendations: 1 There are sufficient numbers of research-grade human embryonic stem cell (hesc) lines for basic stem cell research. It is estimated that more than 350 hesc lines exist worldwide, with 65 ethically-sourced lines currently approved for banking in the UK Stem Cell Bank, and therefore readily available to the research community. These should be sufficient for basic stem cell research without strategic investment in this area. 2 Stem cell technology has important potential for modelling of human disease. Human ESC lines with particular genetic characteristics will be useful for disease-modelling or as new research tools, and their derivation and banking should be encouraged through normal funding routes. 3 The provision of clinical-grade (GMP) hesc lines is a major requirement for the development of stem cell therapies. A modest number of clinical-grade lines should be generated within the next three years, to be banked, as required under HFEA license, within the UK Stem Cell Bank and made available under open licensing to the UK research community. 4 Current arrangements for embryo donation within the UK are adequate for the needs of the envisaged activity. Embryo supply for generic hesc line derivation is not limiting the field. 5 Underpinning knowledge and technologies relating to induced pluripotent stem (ips) cells should be advanced rapidly through seed-corn funding. Induced pluripotency represents a major breakthrough in stem cell research and should be pursued with vigour, in parallel to other stem cell approaches. A large amount of validation and refinement work is required before their utility can be fully established, and funding should be available as soon as possible to advance this research and to help maintain the UK s competitive edge. 6 Enabling links should be strengthened between academic groups and industry. Application of stem cell technologies, either for drug discovery and toxicology screening in the shorter term or therapeutic development in the longer term, will require effective collaboration between the bio-industry sector and academic stem cell research. 7 Regulators should be further encouraged to establish clear requirements for all stages along the therapeutic delivery pipeline so that the UK remains an attractive environment for investment. More clarity/certainty is needed over UK (HFEA/HTA/MRHA) and EU (EMEA) regulatory requirements for development of stem cell therapies, in particular over GMP regulation in relation to the derivation of clinical-grade hesc lines. 3

4 4 1 Purpose of review The review was established to consider the research landscape and the national needs in this area with a view to determining the type of infrastructural support that would best serve the stem cell research sector over the coming years. In particular the review focussed on the derivation and supply of human embryonic stem cell (hesc) lines, and the development of clinical-grade lines for therapy. 2 The UK and stem cell research Stem cell research has a long and fruitful history in the UK. The first embryonic stem cells were derived in the UK from mice over twenty years ago. Professor Sir Martin Evans was awarded the Nobel Prize for Medicine in 2007 for the discovery of mouse ES cells and their contribution to facilitating the development of the transgenic mouse, a groundbreaking technology that has had an enormous impact on research into human development and disease. Further important discoveries relating to ESC research were made by Professor Austin Smith s group, who identified two of the key transcription factors, Oct4 and Nanog, required to maintain the cells in an undifferentiated state. Professor Sir John Gurdon pioneered nuclear transfer and cloning using the frog species, Xenopus laevis, with the first demonstration in 1962 that adult somatic cell nucleii could be reprogrammed to become multipotential embryonic cells and develop into a genetically identical adult. This was later demonstrated to also be true of mammals by the creation of Dolly the Sheep by Professor Sir Ian Wilmut in The world s first baby to be conceived by in vitro fertilisation (IVF) was born in Oldham in This resulted in the UK being the first country to establish legislation (Human Fertilisation and Embryology Act 1990) governing fertility treatment and research using human embryos with a robust but permissive regulatory framework. The Act was amended in 2001 to include hesc research and outlaw human reproductive cloning. The Bill is currently being updated in keep in step with scientific advance. The UK Stem Cell Bank (UKSCB) was the world s first public bank for depositing and distributing stem cell lines. The Bank s mission is to work with and for the scientific and clinical community to assure the quality and ethical-sourcing of human stem cell lines used in research and therapy. 3 MRC stem cell research portfolio During the last four years MRC funding for stem cell research has increased annually to reach 17.6m per annum in 2006/7. A major contribution to this has been through the cross-research Council stem cell initiative, launched in 2003, which injected 40m into the area, 29m from MRC, with the reminder through BBSRC, EPSRC and ESRC. 3.1 Research grant funding MRC funding is awarded competitively through response mode mechanisms, as well as some specific calls for proposals, and supports both intra- and extramural research programmes, capacity building and key infrastructure. The current research portfolio is well balanced. Funding has been awarded to projects on both adult and embryonic stem cells (45:55% spend respectively), and spans fundamental cell biology through to early phase clinical trials. MRC funds over 70 major research projects within Universities, and has major investment in intramural programmes at the National Institute of Medical Research (Mill Hill, London), the Clinical Sciences Centre (Hammersmith, London) and the MRC Molecular Haematology Unit (Oxford). MRC Stem Cell Centres of Excellence have been established at the Universities of Cambridge and Edinburgh. 3.2 Capacity building The MRC acknowledges the importance of building capacity in stem cell research and regenerative medicine, and it will be important to have the appropriate cadre of researchers to take forward and apply the research opportunities as they arise in the coming decade. This has been approached through a number of schemes. Firstly MRC has provided strategic awards to facilitate a number of high profile appointments of stem cell experts to the UK from overseas. At the level of training MRC has funded several New Investigator Awards and fellowships in stem cell research. One particular scheme, the Joint Collaborative Development Fellowship scheme has been run with other funders (both Research Councils and charities) and has provided a total of 25 three-year Fellowships over the past 4 year, 13 with funding from MRC. In addition, the MRC has introduced ear-marked Capacity Building Studentships in stem cell research. 3.3 Infrastructural investment MRC has supported the development of key infrastructure to support the derivation and supply of stem cell lines to the research community. The UK Stem Cell Bank 1 has been established by MRC and BBSRC (see section 4.2), who have invested more than 11m to provide state-of-the-art facilities and operational funding until MRC has provided a further 2m to seven consortia linking IVF clinics and stem cell researchers to address the bottleneck in accessing high quality surplus embryos for stem cell research,

5 and 1.2m to support the upgrades of five IVF clinics to comply with current GMP standards for derivation of clinical-grade embryonic stem cells lines suitable for therapeutic applications (jointly with the Department of Health). The five centres awarded funding are at Birmingham, King s College London, Manchester, Newcastle and Sheffield. 3.4 Strategic initiatives MRC continues to forge key international collaborations through its chairmanship of the International Stem Cell Forum (ICSF) 2, established by MRC in 2003, to link the UK to other countries actively engaged in stem cell research. The membership of the ISCF consists of 21 major funding organisations from Europe, N America, SE Asia, Japan and Australia. A key objective of the ISCF is to harmonise and accelerate stem cell research activity and its application, and to improve global practice in stem cell research. One of its key activities has been the International Stem Cell Initiative (ISCI), a major collaborative effort led by the UK involving many labs throughout the world, which aims to compare and characterise human ES cell lines. The results of phase I, comparing 59 hesc lines derived in a number of countries, have now been published alongside the launch of a stem cell registry to enable data sharing and minimise duplication of effort. MRC is a founding member of Stem Cells For Safer Medicine (SC4SM) 3, a public-private partnership established to develop stem cell technology for use by the pharmaceutical sector to assess toxicological responses to candidate drugs. 1.1m has been provided for phase I, an 18-month programme that aims to establish proof-of-concept for using hescs to reproducibly produce hepatocytes at large-scale for high throughput screening in drug development. 4 State of the science 4.1 Sources of stem cells Stem cells can be isolated from several sources, for example from embryonic, fetal and adult tissue, and very recently reprogramming of human differentiated cells to an embryonic stem cell like state has also been achieved. These cells, named induced pluripotent stem cells (ipscs), are considered to be a major breakthrough in the field. However, it remains uncertain which type of stem cell will provide the most suitable material for any particular therapy, since there are advantages and disadvantages to using stem cells from a particular source. Therefore it is important to undertake research across the full spectrum of stem cells. Improved understanding of basic stem cell biology remains essential if we are to fully understand the mechanisms controlling the choice between self-renewal and differentiation, and results from all stem cell sources will inform developments. Such insight will be a key step in enabling safe and effective application of stem cell technology, whether for clinical therapy, disease modelling, or drug development. i) Adult stem cells Bone marrow transplants have been successfully used for many years to restore immune function after chemotherapy, and therapeutic trials of patients own (autologous) stem cells to restore other tissues are already underway. Current early stage trials are exploring the use of bone marrow SCs in non-homologous settings, for example in the repair of bone/cartilage, heart muscle and vascular tissue. The use of autologous cells negates the possibility of rejection of the transplanted cells and infection; however, the heterogeneity of the transplanted cell population has limited the interpretation and cross-comparability of such studies. Other high profile claims have been made for the multipotency of adult stem cells, for example using umbilical cord blood as a source to repair spinal cord injuries, for regenerating liver, or for the production of artificial sperm. However, the majority of such work is unpublished and unsubstantiated, and most experts remain to be convinced that it is yet possible to utilise adult stem cells in this manner. ii) Fetal stem cells Stem and progenitor cells can be isolated from human fetuses after elective terminations of pregnancy at early gestational stages. Proof-ofconcept has been achieved in animal models for using fetal neural stem cells as treatments for neurodegenerative conditions, such as Parkinson s and Huntington s disease, where human trials have also been performed, and for eye conditions such as age-related macular degeneration (AMD). iii) Embryonic stem cells (hescs) Stem cells can be isolated from human embryos at 5-6 days after fertilisation. The embryos used are those that are spare after IVF treatment and are donated for hesc research. Therapies derived from hesc lines are 2-3 years away from clinical trial, and therefore some 5-10 years away from the clinic. Early targets for clinical trials are the repair of spinal injuries (USA), retinal damage (London), bone and cartilage repair (Edinburgh) and the neurodegenerative disorders Parkinson s and Huntington s Diseases. Nearer term use is likely to be in drug development/toxicology screens and modelling of disease progression. While hescs require much greater developmental time than stem cells from other sources, therapies based upon hescs are likely to be highly defined, purified and controllable, and have the potential to be applied in a broad range of clinical situations. iv) Endogenous stem cells Most tissues are now considered to harbour dormant stem cell populations, and current research is aiming to stimulate such cells to direct the repair of damaged or diseased cells and tissues. In the longer term many experts consider this is likely to be the major clinical use of stem cell technology. A recent MRC experimental medicine award is pursuing this approach in stroke patients, while vascular repair and wound healing also employ such approaches. 5

6 6 Stem cells are now thought to underlie several cancers and may provide the major target for novel drug development in oncology over the next decade. v) Somatic cell nuclear transfer (SCNT) This technology involves the generation of embryos through the reprogramming of a differentiated nucleus from a donor somatic cell after transfer into an enucleated egg. This approach has been used to clone 14 different animal species to date, though it remains inefficient and has not yet been reliably demonstrated using human eggs. However, the adoption of a modified technological approach led to successful SCNT in monkeys in November 2007, which has raised hopes that this will be achievable using human eggs in the not-too-distant future. Since donated human eggs are in short supply researchers are also interested in perfecting this technique by transferring human nuclei into enucleated animal eggs; such an approach would lead to the generation of so-called admixed embryos containing a minor fraction of animal DNA (within mitochondria, and constituting less than 0.5% of the total genetic material). In humans SCNT will be used purely to generate early-stage embryos for the derivation of hesc lines - under UK legislation embryos may not be developed beyond a 14-day limit, while reproductive cloning is outlawed. The long-term potential is to generate therapeutic hescs with the nuclear genetic material of the patient to avoid the potential immune rejection of the transplanted cells. However, once achieved it is likely that the first use of human SCNT will be in deriving stem cells with genetic mutations associated with human disease for research into the disease-causing process, or of defined genetic background for drug screening. ips cell technology might also be a route to achieve this (see below). vi) Induced pluripotent stem cells (ips cells) During the past year it was discovered that differentiated cells, such as fibroblasts from skin, could be reprogrammed into pluripotent stem cells by the addition of a specific set of genes. The resulting induced pluripotent stem cells (ipscs) appear to have many properties in common with ESCs, including the capacity to self-renew and differentiate into cell types of all three germ layers. The generation of ips cells was first achieved in mice in 2006 by reprogramming through the over-expression of four transcription factors. The reprogramming of human fibroblasts has recently been demonstrated by groups in both the US and Japan. ips cell technology has the potential to have a major impact over the coming years, and will open up the field to most research groups with cellular and molecular biology expertise. In addition ips cells avoid most of the ethical debate surrounding the use of hescs. However, such research is at a very early stage, and their potential for clinical use is uncertain due to the major safety issues inherent through the current technology of using retro- or lentiviruses and transcription factor over-expression. Thus the immediate application of ips cell technology will be for understanding basic stem cell biology and for use in disease modelling and drug discovery, rather than for developing clinical therapies where further validation and refinement will be essential. 4.2 Supply of stem cells i) UK governance of hesc lines A requirement of holding a license from the HFEA to derive hescs is that any line generated must be deposited within the UK Stem Cell Bank (UKSCB), located at the National Institute for Biological Standards and Control (NIBSC), for characterisation, quality assurance and expansion for distribution. The Bank operates in accordance with strict principles of governance laid down by a high level committee, chaired by Lord Patel of Dunkeld, known as the Steering Committee for the UK Stem Cell Bank and the Use of Stem Cell Lines 4, for which the MRC provides the secretariat. The Bank reports to and is overseen by the Steering Committee. In addition, the Bank operates under a Code of Practice drawn up by the Steering Committee, which is in addition to the regulatory framework provided by EU cgmp and other EU Directives. A Management Committee, with lay representation as well as representatives from research, healthcare, the regulatory bodies and the Bank s sponsors, monitors the Bank for adherence to the Code of Practice and assists in the Bank s strategic development. The use of hesc lines in the UK more generally is also overseen by the Steering Committee, which is charged with approving all such research on a project-by project basis. More detailed information regarding this governance can be found in The Code of Practice for the Use of Human Stem Cell Lines. 5 ii) UK Stem Cell Bank 1 As of March 2008, a total of 65 hesc lines have been approved for banking in the UK Stem Cell Bank. The status of these cell lines is as follows: 54 have been accessioned by the Bank, 10 are available for distribution, and a further 12 have completed the banking process and are currently undergoing QC testing for release soon. Prior to qualitycontrolled stocks being available through the Bank, researchers can apply to obtain the approved hesc lines directly from the derivation labs. 36 of the 65 cell lines originate from labs in the UK and the rest were derived overseas, including the US, Australia, India and Sweden. Currently all of these lines are research grade, and include 4 that are disease specific, one of which has the genetic mutation that causes cystic fibrosis and three with mutations for Huntington s Disease. The characterisation, quality testing and creation of master stocks of quality-controlled hesc lines is a lengthy process, and at its current capacity the Bank can process 12 hesc lines per year ready for distribution. The distribution of lines is also dependent upon successful negotiation of Materials Access Agreements with the derivation centres.

7 The Bank is supplying (or in negotiations with the intent to supply) hesc lines to about 20 groups worldwide, with more than half of these within the UK. The Bank is aiming to raise awareness in the stem cell community of the operational supply system and to streamline access to cell lines. In addition, the UKSCB offers training to stem cell researchers. iii) International sources Several other countries have opened national stem cell banks for depositing, characterising and distributing human stem cell lines. The most developed are: USA: 6 The National Stem Cell Bank (NSCB) at WiCell Research Institute is a repository for the pluripotent stem cell lines listed on the NIH Stem Cell Registry. These cells were derived prior to August 2001 using excess IVF embryos and are therefore eligible for use in federally funded research in the United States. The NSCB Scientific Advisory Board provides guidance on NSCB policies and decisions regarding resource utilization and scientific direction, and includes representation from providers who have deposited cell lines in the NSCB, as well as others from the hesc research community. Singapore: 7 The Singapore Stem Cell Bank (SSCB) is the centralised repository and distributor of human stem cells lines hosted by the Singapore Stem Cell Consortium (SSCC) and is an initiative of the Agency for Science, Technology and Research (A*STAR). Spain: 8 The National Bank of Cell Lines (Banco Nacional de Lineas Celulares, BNLC) is a network structure coordinated from the Ministry of Health (Instituto de Salud Carlos III). There are three regional nodes: Barcelona, Valencia and Granada. All hesc lines derived within the national territory must be deposited in the BNLC. 4.3 Therapeutic development i) Background Stem cells from the bone marrow have been used for the treatment of haematological disorders, such as leukaemia for about 50 years. Other therapies aimed at replacing cells lost or damaged through disease have been in development for decades, and indeed in early clinical trial in humans, including the use of a specific neuronal cell type (dopaminergic) harvested from human foetuses at early gestational ages after elective terminations and transplanted into the brains of patients suffering from Parkinson s Disease (PD) and transplantation of insulin-producing (ß-islet) cells from the pancreases of cadaveric donors into patients with Type I diabetes. Some of the patients participating in these trials have remained off medication in the long-term (L-Dopa in the case of PD or insulin for diabetes) and therefore provide proof-of-concept that cell replacement strategies can be effective in the treatment of degenerative diseases. However, there are still many hurdles to overcome before such experimental treatments can become routine clinical practice. Unwanted side-effects from the transplantations need to be better controlled, while one logistical problem is an adequate supply of donor tissues or cells to meet demand (e.g. ten 6-8 week foetuses are needed to effectively treat one PD patient; 2-3 cadaveric donors required per diabetes patient), hence only few patients have been treated worldwide. A relatively unlimited supply of cells for transplantation will be necessary to treat a large number of patients that is only likely to increase with an aging population. Stem cells have the potential to provide a theoretically infinite source of cells for transplantation, either using the patient s own stem cells in autologous therapies or through allogeneic therapies derived from ex vivo expandable stem cells such as hescs. There are benefits and difficulties associated with either route, and these vary depending on the cell type and the clinical indication. Some of these are addressed in the examples provided below. ii) Cardiac disease Development of cell therapies for heart disease is aimed at increasing cardiac function by either replacing damaged cardiomyocytes or improving neovascularisation. The possible mechanism by which this may be achieved is as yet undetermined, but could include strategies to allow remaining cardiomyocytes to regain proliferative potential, to protect remaining cardiomyocytes from cell death, to introduce new cardiomyocytes through differentiation of exogenous cells or to target angiogenesis. Accordingly, this is likely to determine the type and source of the transplanted cells, the route of administration (e.g. intracoronary infusion, intramyocardial injection by catheter or during surgery) and the timing for administering any treatment that is developed (e.g. early or late after myocardial infarction). To date, preclinical studies in animals and a few clinical studies in patients have been conducted. These have used cells from a variety of sources including autologous cells from bone marrow, skeletal muscle, adipose tissue and peripheral blood or allogeneic cells such as the differentiated progeny of embryonic stem cells. Based on early preclinical data in animal models showing some improvement in cardiac function after infusion of bone marrow cells, a number of clinical trials have been conducted using autologous bone marrow cells. Results of these studies have been heterogeneous, but importantly so have the trial protocols and what has therefore been learned is that factors, such as cell number and identity, timing of treatment and the patients treated, may be critical. Early animal studies had generated a theory that bone marrow progenitors or mesenchymal stem cells could differentiate into cardiomyocytes within the environment of the healing heart. This is now thought to be an unlikely mechanism of action, and evidence instead points towards vascular mechanisms. Interestingly and importantly, there is a trend towards benefit in the short term, with little evidence of harm, but large 7

8 8 clinical outcome studies are needed to conclusively establish this and these studies should be used to inform mechanistic studies. Other clinical trials using skeletal muscle and adipose tissue derived stem cells have been conducted, but the results are as yet inconclusive. Embryonic stem cells can differentiate into cardiomyocytes. Animal studies using infarct models have shown some improvement in cardiac function after transplantation of ESC-derived cells. However, survival and integration of differentiated cells with host myocardium is low. Recent studies suggest survival factors are required for engraftment in the hostile transplant environment. Prior in vitro differentiation of cells (and possibly selection of these progeny) is important to avoid teratomas forming from transplanting undifferentiated ESCs, which is a significant safety issue for therapeutic development. A more detailed understanding of the differentiation signals will enhance the ability to generate bone fide cardiomyocytes with greater purity for the development of stem cell therapy for heart disease from hescs. iii) Diabetes (Type 1) Diabetes is a result of the destruction of insulin secreting cells in the pancreas due to autoimmune disease. The proof-of-principle for stem cell therapy in Type 1 Diabetes was established with the Edmonton Protocol in 2000 transplanting pancreatic islets from cadaveric donors into the hepatic portal vein. Significant optimisation is still needed before this could be a routine treatment. There are alternative strategies for cellular therapy for diabetes being investigated ranging from immunomodulatory approaches using bone marrow stem cell transplantation (which carry a very high risk), to identifying scalable sources of ex vivo beta cells such as foetal progenitors of differentiated hescs. Stem cell therapies must be weighed up against existing treatments. Diabetes can be treated with insulin, but there is a year reduction in life expectancy and reduction in quality of life. Insulin is not a cure however, which is the ultimate goal of a cell therapy, but does provide a higher bar for measuring success and gaining wide spread acceptance among patients and clinicians than perhaps for other diseases where there may be no effective treatments. The current challenges in developing a cell therapy from hescs is the reproducible production of a large number of physiological glucose-sensing/ insulin-secreting islets (not unassembled ß-cells), that can survive and engraft to function better than exogenous insulin, without the formation of teratomas. iv) Neurodegenerative disease Neurodegenerative diseases are progressive and debilitating diseases that represent a major unmet clinical need, lack effective treatments and are therefore a target for potential stem cell therapies. Human stem cells offer an experimental resource as the only method of acquiring defined neural stem cells on a scale necessary for experimental study, drug discovery and disease modelling. They also offer a potential therapeutic resource through exogenous replacement of lost cells, promotion of endogenous repair and cell protection, but perhaps also through delivery of growth factors and drugs or with more novel immunomodulatory or anti-inflammatory roles. To develop such treatments, it is necessary to have an insight into disease pathogenesis and this section will describe the current status for Parkinson s disease, multiple sclerosis and motor neurone disease as examples. Parkinson s disease (PD) is the second most common neurodegenerative disease, and results from the selective loss of dopamine producing neurons in the brain in the absence of endogenous repair. Proof-of-concept for cell replacement was by transplanting foetal ventral mesencephalic tissue, and although there was clinical benefit in some patients, there were problems with tissue availability and conclusive demonstration of safety and sustained efficacy. Further trials are needed to demonstrate this. In addition, a scalable and appropriate source of cells needs to be identified. There has been some success in relieving Parkinsonian symptoms in rodent models of PD using dopaminergic progenitors from murine ESCs, but this has so far been more difficult to replicate with hescs. Multiple sclerosis (MS) is an autoimmune disease that results in the loss of myelin from neurones in the brain and spinal cord, affecting transmission of neuronal impulses and eventual death of the cell. Immunomodulatory approaches using autologous bone marrow stem cells are in clinical trial, but so far results are inconclusive. Other cell therapy strategies involve repair of the myelin using oligodendrocyte progenitor cells derived, for example from ESCs. A major hurdle will be in cell delivery due to the systemic nature of the disease, but pathotropic properties of the transplanted could facilitate homing to disease foci. There are also many clinical questions regarding identifying suitable recipients for and timing of a treatment, due to the highly variable clinical course of MS. Motor Neuron Disease (MND) results in the destruction of motor neurons with loss of movement and eventual death. Direct neuronal transplantation is currently an unrealistic therapeutic strategy due to the widespread pathology of the disease, the length of cell growth required and the complex neuronal connections that must be established. However, non-neuronal cell transplantation for tissue protection to limit cell loss through stem cell derived growth factors or modulation of the toxic host environment is a potential approach, as is exploiting antiinflammatory or pathotropic properties of stem cells. 4.4 Requirements for basic, translational and clinical research More than 350 hesc lines have been generated worldwide, 34 of which are from the UK, which represents good productivity from the previous

9 infrastructural investment targeted at this activity. There is still the need for much basic research to understand the biology of stem cells, such as the mechanisms controlling self-renewal and differentiation. The ultimate goal of stem cell research is clinical application. Basic research on these existing lines can provide mechanistic insight that may facilitate development of differentiation protocols to reproducibly generate pure populations of specific cell types for clinical application, either by directed differentiation and/or identification of biomarkers for subsequent cell selection. These findings must be translated to produce therapeutically useful cell products, by deriving cell culture and differentiation protocols that are suitable for future clinical use, conducting extensive safety and efficacy studies in animal models, in a clinical context for future trials. Existing hesc lines are heterogeneous with respect to the detailed methods for derivation and culture, and with their respective propensity to differentiate down various cell lineages. The reasons for this are yet to be established. International efforts have been made to compare many of these lines, but more co-ordination will be necessary to develop clinical therapies, including animal-free, chemically defined culture media for consistent results, as protocols and results vary widely between labs making comparisons difficult. Furthermore, to comply with EU Directives and UK regulations (see Section 5) cells intended for future clinical use in this country must be derived and handled to meet designated standards. There are no known clinical-grade hesc lines available that meet current standards, and will therefore have to be derived. For approval of first-to-man Phase I safety studies of hesc derived cells, the preclinical animal studies will have to be conducted using progeny of the same cell line as in the proposed clinical trials. hesc lines suitable for human use could be derived and banked, with twin lines generated and made available for preclinical research. A major question is the number of clinical grade cell lines that will eventually be required. It has been suggested that >150 hesc lines would be needed to represent HLA types of most of the UK population to tackle the problem of immunemediated rejection 9. However, this may depend on the relative antigenicity of the hesc derived cells being transplanted, and on the potential for inducing immunological tolerance to avoid the problems associated with long-term use of immunosuppressive drugs. Although optimum derivation and culture conditions are still evolving and issues regarding tissue matching are unresolved, availability of some clinical grade hesc lines would undoubtedly facilitate therapeutic development over the next five years. i) Drug development hescs have a potential use in cell-based screens and assays for the preclinical testing of drug metabolism and toxicology. There is a significant bottleneck in the screening of new pharmaceutical compounds and a high number of drugs fail during clinical trials due to unpredicted toxicity or adverse interactions with drug metabolising enzymes in the liver, at great cost to the pharmaceutical sector. At present, primary cell lines derived from human livers obtained from cadavers or during liver resection are used in preclinical assays, but these are hugely variable and cannot be sustained in culture for long. hescs may provide a potentially scalable, consistent and infinite supply of hepatocytes that could also be representative of a wide range of genotypes. Similarly, other cell types that have a high frequency of adverse reactions from drugs, such as cardiomyocytes, would also be useful. ii) Disease modelling There is a major research need for diseasespecific hesc lines, which have the potential to provide the material for studies on cells accurately representative of the human condition, which is not wholly achievable using immortalised cell lines or animal models. In addition hesc lines may offer new opportunities to study rare childhood conditions or the early determinants of late-onset disorders such as neurodegenerative diseases. Such lines are obtained at present from embryos that were created by IVF and found to have a genetic lesion during preimplantation genetic diagnosis (PGD). hesc lines carrying genetic mutations can be differentiated to generate the cell type(s) affected by a particular disorder and used to study disease pathology or for drug screening. There are currently over 50 diseases that may be tested for using PGD, such as Huntington s disease, muscular dystrophy and cystic fibrosis. However, PGD is generally not available for late onset diseases. A possible approach being researched where PGD embryos are not accessible is to derive hesc lines through somatic cell nuclear transfer (SCNT) using skin cells donated by patients. ips cell technology is also likely to make a significant impact on generating cell lines for disease modelling. 5 Regulation 5.1 EU Tissue and Cells Directive (2004/23/EC) 10 The EUTCD is the regulatory framework setting Good Manufacturing Practice (GMP) standards of quality and safety for the donation, procurement, testing, processing, preservation, storage, distribution, tracking and reporting of tissues and cells destined for human transplantation. All stem cells and cell lines grown outside the body destined for therapeutic use, whether derived from adult, foetal or embryonic sources, fall within the remit of the Directive. This includes gametes and embryos but does not include e.g. blood components, engineered tissue or whole organs for direct transplantation without being stored. The EUTCD was legally binding from April 2006, with compliance from July

10 UK regulation 11 In the UK, current GMP (cgmp) relating to stem cells will be enforced through licensing and inspection by three regulatory bodies. The proposed remits of each body is outlined here, although the details are still being discussed. The Human Fertilisation and Embryology Authority (HFEA) regulates gametes and embryos, including the use of embryos in the derivation of stem cells, but not the cell lines once they have been derived. The Human Tissue Authority (HTA) regulates the use of all human cells and tissues, except gametes and embryos, but includes the processing, storage and distribution of stem cell lines for human application. The Medicines and Healthcare products Agency (MHRA) regulates cell lines only once Master Cell Banks have been created and there is a reasonable expectation of their clinical use in a medicinal product. During the derivation and processing phases, stem cells do not come within medicines regulation, even if they are intended for eventual clinical use. There is some ambiguity over coordination among regulators within the UK, and between the UK, EU and US. Uncertainty over regulators jurisdictions, together with evolving standards of cgmp has contributed to a delay in the accreditation of newly upgraded IVF/hESC cell derivation facilities. Elsewhere within the European Union cgmps are enforced by the respective National Regulatory Agencies and in the United States this is by the Food and Drug Administration (FDA). In regard to the changing standards of cgmp for cell therapies, a general aim is to avoid using animal products in treatments for humans. However, this is not straightforward, as some animal products or cell lines have a history of safe human use, e.g. mouse 3T3 cells may comply with cgmp, whereas new animal products may not. Furthermore, there are differences between the US and EU. The FDA will consider Investigational New Drug (IND) applications to conduct clinical trials on cell therapy products derived from the original hesc lines derived by Professor Jamie Thompson in the USA, which were generated and cultured using mouse feeder cells and other reagents with animal products. However, for intended future human use, the cells have been re-derived in animalfree culture conditions and undergone extensive screening for known infectious agents, including tracing of the embryo donors and reagent sources. The FDA currently views such cell therapy products as xenografts. These hesc lines are unlikely to qualify as suitable for human use according to the EUTCD, and new hesc lines must be specially derived for clinical use in the UK/EU. In November 2007, ES Cell international reported the world s first clinical grade hesc lines (6 lines), derived to meet standards for human use in the EU, but again, with questions over evolving standards this is unconfirmed. GMP-grade lines derived in accordance with the EUCTD could be produced in the UK in the next months. 6 Recommendations of the Expert Group Based on the findings of the review, a number of recommendations were made by the Expert Group on funding priorities for stem cell infrastructure and possible mechanisms for provision of this support. These have been presented to the MRC. An important part of the review was to assess the availability of hesc lines for research and the requirement for clinical grade hesc lines for development of stem cell therapies. In summary, the number of lines in existence was deemed sufficient to meet the needs of the research community for studies on basic stem cell biology and therefore investment in new lines for this purpose is not a priority. The provision of clinicalgrade hesc lines, however, would benefit from specific investment as there are currently no such lines available that comply with EU regulations and it is recognised that generating these lines is costly. There will be a demand for grant funding to support projects investigating new derivation methodology or for generating lines with particular genetic characteristics for modelling human disease as well as other stem cell technologies, such as induced pluripotency. The strength of stem cell research in the UK is such that competitive funding through the normal response mode mechanisms for hypothesis-led proposals should be, for the most part, sufficient to maintain momentum in the field. 1 There are sufficient numbers of research grade human embryonic stem cell lines for basic stem cell research. It is estimated that more than 350 hesc lines exist worldwide, with 65 currently approved for banking in the UK Stem Cell Bank, and therefore readily available to the research community. These should be sufficient for basic stem cell research to explore mechanisms underlying self-renewal and differentiation, genetic stability, imprinting and growth characteristics. There is therefore no need for further strategic investment in this area. Where deriving new research grade lines might be necessary, such as in the development of new methodologies to support stem cell research, this should be funded in competition with other research through existing response-mode mechanisms. 2 Stem cell technology has important potential for modelling of human disease and as research tools. The derivation of hesc lines with particular genetic characteristics, either for disease-modelling or as new research tools, should be funded through normal response-mode approaches. This should facilitate linkage between groups with expertise in the derivation and handling of hesc lines to those best placed to undertake research into pathophysiological and developmental mechanisms.

11 3 The provision of clinical-grade (GMP) hesc lines is a major requirement for the development of stem cell therapies. It is recognised that the costs of generating GMP lines are considerable. The number of GMP-grade hesc lines needed to support clinical development is still uncertain and will depend on scientific advances in stem cell research. However, a modest (10 to 20) number of clinical grade lines should be generated for the UK research community within 3 years. This should be delivered through a competitive call for proposals, and build upon previous MRC/DH investment in GMP facilities, such that funded groups have facilities with established and fully compliant cgmp procedures. The lines should be banked, as required under HFEA license, within the UK Stem Cell Bank and should be made available under open licensing/mta agreements. 4 Current arrangements for embryo donation are adequate for the needs of the envisaged activity. The funding provided to link IVF facilities and derivation labs has led to an effective arrangement for the donation of embryos for research, and embryo supply for generic hesc line derivation in the UK is not limiting. In the future nursing support at derivation centres should be provided in the most part through funding for IVF facilities, with research costs provided on MRC awards where appropriate. 5 Underpinning knowledge and technologies relating to ips cells should be advanced rapidly through seed-corn funding. Induced pluripotency represents a major breakthrough and should be pursued with vigour, in parallel to other stem cell approaches. The technology needs further validation and refinement, and much work remains before the technology might be considered safe enough for the development of clinical therapy. A much wider array of research groups (both in the UK and worldwide) are likely to become involved in stem cell research as a result of ips technology, and this will be mostly be supportable through standard hypothesis-led grants, but the early window of opportunity should be used to help advance the field and maintain the UK s competitive edge. Consideration should be given to how best to provide rapid, seed-corn funding to provide a platform for future research in this area. 6 Enabling links should be established between academic groups and to industry. Reagents: The costs of undertaking hesc research are high, and the UK Stem Cell Bank should be asked to scope whether there are opportunities to centrally supply high quality reagents at low cost for the benefit of the wider UK stem cell research community. Industry links: An early application of stem cell technology will be for drug discovery and toxicology screening, and MRC should work to promote better integration of the needs of the bioindustry sector with academic stem cell research. This would also benefit the longer term goal of developing therapies for regenerative medicine. 7 Regulators should be further encouraged to establish clear requirements for all stages along the therapeutic delivery pipeline so that the UK remains an attractive environment for investment. More clarity/certainty is needed over UK (HFEA/HTA/MRHA) and EU (EMEA) regulatory requirements for therapeutic development, in particular over where GMP regulation should begin in relation to the derivation of hesc lines. Following these recommendations, the MRC launched two targeted calls for proposals in the spring 2008 for: seed-corn funding to develop platform technologies for human ips cell research; Derivation of clinical grade hesc lines for the development of stem cell therapies; For details please visit 11

12 Annex: Methods used to conduct review 1 Membership of the MRC Expert Group Lord Patel of Dunkeld (chair) Professor Peter Andrews Dr Alan Coleman Professor Steve Dunnett Dr Anne Ferguson-Smith Dr Stephen Hammond Professor Doug Higgs Professor Roger Pedersen Dr Rob Buckle Dr Anna Krassowska chair of The Steering Committee for the UK Stem Cell Bank and the Use of Stem Cell Lines University of Sheffield and MRC Molecular and Cellular Medicine Board a*star Singapore and King s College London University of Cardiff and MRC/UKSCF Scientific Advisory Board University of Cambridge and MRC Molecular and Cellular Medicine Board Scottish Biomedical and MRC/UKSCF Scientific Advisory Board University of Oxford and MRC/UKSCF Scientific Advisory Board university of Cambridge Secretariat, MRC Head Office observer, UKSCF 12 2 Terms of Reference In the light of evidence received in response to consultation with stakeholders, the terms of reference for the review were: i) to review the effectiveness of MRC s current support to underpin the provision of human embryonic stem cell (hesc) lines using ring fenced funds allocated under SR2002; ii) To assess the UK s requirements hesc stem cell supply for both research and clinical use over the coming 5 years; iii) to make recommendations as to the scale and nature of the strategic investment that would be required to provide the support (including infrastructure) necessary to maintain the UK s lead in this area; iv) To advise the MRC Boards and Council (and inform appropriate committees of the other charities and Councils) on the funding priorities and possible mechanisms for provision of this support, as well as its ongoing review in the light of likely scientific advance. 3 Review format The review was undertaken over the course of three meetings during the autumn/winter 2007: 28 August initial scoping meeting; 30 October stakeholder workshop, informed by consultation exercise (see below); 6 December final review meeting. Stakeholder workshop A one-day workshop was held with the Expert Group and invited stakeholders, including representatives from IVF clinics/hesc derivation acilities, stem cell researchers (hesc and adult stem cells fields), clinicians, ethicists/sociologists and experts in GMP from the regulatory bodies (MHRA, HFEA), UK Stem Cell Bank and National Blood Service. The first half of the workshop contained a series of presentations to inform a discussion among the group. introduction and background to review, Lord Patel (Chair of Expert Group) summary of online consultation exercise, Dr Rob Buckle (MRC) immunological issues for stem cell therapy, Professor Robert Lechler (KCL) stem cells for disease modelling, Professor Marc Peschanski progress towards the clinical use of stem cells in i) Cardiovascular Disease, Professor David Crossman (Sheffield) ii) Diabetes, Professor Neil Hanley (Southampton) iii) neurodegeneration, Dr Siddharthan Chandran (Cambridge) stem cell banking and regulation, Dr Glyn Stacey (UK Stem Cell Bank During the second part of the workshop the attendees were split into four parallel discussion groups, each chaired by a member of the Expert Group and asked to consider a set of six key questions on the: number of hesc lines needed in the future for research and clinical use, the particular characteristics required and the timescale;

13 hurdles for development of GMP hesc lines (differences to other cgmp biologics, potential deficiencies in the current regulatory framework); potential need for national coordination forembryo supply, derivation of stem cells, standardisation of methodology, GMP facilities; possible links to bio-industry; availability and communication of information to the public. Online consultation To support the stakeholder workshop, a web-based consultation was conducted over a period of three weeks. notification of the consultation was sent to Research Council and Wellcome Trust stem cell grant holders, users of the UK Stem Cell Bank/applicants to UK Stem Cell Steering Committee, the UK National Stem Cell Network contact database and other key stakeholder groups (API, BIA, RDA s). Approximately 65% of respondents defined their area of expertise as basic or clinical research, spanning the hesc and adult stem cell fields. Their geographic distribution throughout the UK was good, and approximately 10% were from overseas. The remaining 35% represented industry, funders, regulators and patient groups. Most of the respondents (90%) were in agreement that the supply of new hesc lines should continue to be considered a national strategic issue that requires a coordinated approach from the MRC and other funders. When asked whether there were research questions that could not be addressed using the existing hesc lines, there was broad agreement that this was the case. The possible research questions put forward included the need for new lines with specific genetic characteristics for modelling of human genetic disease (e.g. derived from discarded PGD embryos or generated by SCNT from patients skin cells) and for improving derivation efficiency and developing defined culture conditions. However, there was no agreement on the number of new hesc lines that were likely to be required in the foreseeable future. In addition, the derivation of clinical grade hesc lines was widely considered as important for the development of cell therapies, including a need for lines representing diverse genotypes and from ethnic minorities. When asked for details of any clinical trials for hesc-based cell therapies, either ongoing or planned for the next two years, some of the respondents drew attention to Geron Corporation s previous announcements of an intention to file an application to the US FDA to commence phase I safety studies using oligodendrocyte cells derived from hescs for spinal cord injury, on completion of preclinical safety and efficacy IND-enabling animal studies in The respondents highlighted a number of hurdles that must be overcome for the development of GMP hesc lines for potential clinical use, ranging from enabling research and technology such as defined derivation and culture conditions, source and quality of GMP compliant reagents, robust and reproducible control of differentiation, scale-up of cells and manufacturing, through to clarity and coordination on regulations within the UK and the EU. The respondents also wished for greater awareness on stem cell technology through accurate public engagement and dialogue. 13

14 References: 1. The UK Stem Cell Bank (UKSCB) 2. International Stem Cell Forum (ISCF) 3. Stem Cells for Safer medicine (SC4SM) www Steering Committee for the UK Stem Cell Bank and Use of Stem Cell Lines 5. The Code of Practice for the Use of Human Stem Cell Lines 6. The National Stem Cell Bank (NSCB) 7. The Singapore Stem Cell Bank (SSCB) 8. The National Bank of Cell Lines (BNLC Spain) 9. Taylor C et al The Lancet, Volume 366, Issue 9502, Pages European Union Directives EU Tissues and Cells Directive (European Parliament and Council Directive 2004/23/EC) First Technical Directive to EUCTD (Commission Directive 2006/17/EC) This relates to certain technical requirements for the donation, procurement and testing of human tissues and cells. Second Technical Directive to EUTCD (Commission Directive 2006/86/EC) This relates to traceability requirements, notification of serious adverse reactions and events and certain technical requirements for the coding, processing, preservation, storage and distribution of human tissues and cells UK Regulations Human Tissue (Quality and Safety for Human Application) Regulations 2007 The EUCTD was transposed into national law effective from July uksi_ _en_1 Directions The Human Tissue Authority (HTA) issued a set of Directions to establishments storing tissues and cells for human use to secure compliance with the Directives: Directions 001/2006 Summarize the requirements of the EUTCD and first Technical Directive. document.pdf Directions 002/2007 Set out the requirements of the Human Tissue (Quality and Safety for Human Application) Regulations 2007 and the second Technical Directive of the EUTCD and supplement and amend the first set of Directions. Act_2004_implementing_the_Human_Tissue Final.pdf

15 Directions 004/2007 These Directions came into force in October 2007 and stipulate that imports of tissues and/or cells from non-european Economic Area (EEA) states meet standards of quality, safety and traceability equivalent to those provided in the Human Tissue (Quality and Safety for Human Application) Regulations Human Fertilisation and Embryology Authority (HFEA) Human Tissue Authority (HTA) Medicines and Healthcare products Regulatory Agency (MHRA) Joint statement from the Human Tissue Authority (HTA), Human Fertilisation and Embryology Authority (HFEA) and Medicines and Healthcare products Regulatory Agency (MHRA). stem_cell_lines_for_human_application.cfm 15