**2.7 Current clinical trials with iPSCs**

In 2014, Mandai et al. reported the results of the world's first clinical study of iPSCbased therapy in patients with advanced neovascular age-related macular degeneration (AMD) [45]. In this trial, two patients were recruited, and iPSCs were generated from the skin fibroblasts and were further differentiated into retinal pigment epithelial (RPE) cells [45]. One patient received the autologous iPSC-derived RPE cell sheet under the retina. A one-year follow-up on this patient revealed no apparent improvement nor worsening in her vision, and the transplanted sheet remained intact [45]. For the other patient, however, aberrations in DNA copy number were identified in the derived iPSCs and RPE cells, but not the starting fibroblasts, implying that genome mutations occurred during the reprogramming process [45]. This patient did not receive the treatment. Indeed, this clinical trial was suspended due to the

**105**

*Innovations in Human Stem Cell Research: A Holy Grail for Regenerative Medicine*

discovery of genetic mutations in the iPSCs. In 2017, five patients were recruited and treated for the same eye condition with iPSC-derived retinal cells. However, in this trial, the iPSCs were of an allogeneic source and created at Kyoto University Center for iPS Cell Research and Application (CiRA). One of the patients developed a serious reaction to the transplant. After removal of the engineered membrane graft, the symptoms were improved [46]. The efficacy of the treatment in other patients has not

In addition to the iPSC-based therapies in AMD, in May 2018, Japan's health ministry approved cardiac surgeon Yoshiki Sawa at Osaka University to assess the safety of allogeneic iPSC-derived cardiomyocytes in patients with heart disease [47]. This research team has previously reported the efficacy of grafting of human iPSC-derived cardiomyocytes cell sheet in combination with an omental flap technique in a porcine model of ischemic cardiomyopathy [48, 49]. In the projected human trial, the treatment will initially be given to three people; then the team will seek approval to conduct a clinical trial in approximately 10 patients [47]. If these initial clinical studies prove successful, the treatment will be made commercially available soon after under a new fast-track system in Japan designed to speed up the

In October 2018, neurosurgeons at Kyoto University Hospital also performed the first iPSC cell-based therapy in patients with Parkinson's disease (https://www.kyotou.ac.jp/en/research/events\_news/department/hospital/news/2018/181109\_1.html). In this first human study, 2.4 million allogeneic iPSC-derived dopamine precursor cells were deposited into 12 sites of the patient's brain with known dopamine activity. At the time of the press conference on this procedure, November of 2018, the investigators described that the patient was "doing well." The human iPSC-derived progenitor cells have shown to improve the symptoms in a primate model of Parkinson's disease [50]. As compared to Japan's fast-forwarding pace of initiating human trials with iPSC-based therapies, the scientists and physicians in the United States are approaching this direction with more caution, even though several human ES cell-based therapies have been initiated in clinical studies [51]. For the treatment of Parkinson's disease, Lorenz Studer at Memorial Sloan Kettering Cancer Center has focused on generating dopamine neurons from human ES cells at a sufficient scale and purity and demonstrated their efficient engraftment and function in mouse, rat, and monkey models of Parkinson's disease [52]. Based on those results, the group is currently pursuing an investigational new drug (IND) application from the US Food and Drug Administration (FDA), to initiate the first human clinical use of ES cell-derived dopamine neurons [52]. In November 2018, Fate Therapeutics, Inc., a biopharmaceutical company, announced that the FDA approved their IND application for FT500, the company's universal NK cells derived from a clonal master iPSC line. Using an in vitro three-dimensional tumor spheroid model, the company demonstrated that FT500, in combination with activated T cells and an anti-programmed death (PD)-1 antibody, led to near-complete elimination of target cells (>99% reduction) [53]. The company plans to initiate first-in-human clinical testing of FT500 in combination with checkpoint inhibitor therapy for the treatment of advanced solid tumors. This is expected to be the first-ever clinical

investigation in the United States of an iPSC-derived cell product.

In 2016, Cynata Therapeutics also launched a phase I clinical trial in both the United Kingdom (UK) and Australia using allogeneic iPSC-derived MSCs (differentiated from iPSCs through intermediate-stage mesenchymoangioblasts) (CYP-001) for the treatment of steroid-resistant acute graft-versus-host disease (aGvHD) in patients undergoing an allogenic stem cell transplantation. In 2018, the company reported that CYP-001 met all clinical endpoints and demonstrated positive safety and efficacy

*DOI: http://dx.doi.org/10.5772/intechopen.88790*

development of regenerative therapies [47].

been reported.

### *Innovations in Human Stem Cell Research: A Holy Grail for Regenerative Medicine DOI: http://dx.doi.org/10.5772/intechopen.88790*

discovery of genetic mutations in the iPSCs. In 2017, five patients were recruited and treated for the same eye condition with iPSC-derived retinal cells. However, in this trial, the iPSCs were of an allogeneic source and created at Kyoto University Center for iPS Cell Research and Application (CiRA). One of the patients developed a serious reaction to the transplant. After removal of the engineered membrane graft, the symptoms were improved [46]. The efficacy of the treatment in other patients has not been reported.

In addition to the iPSC-based therapies in AMD, in May 2018, Japan's health ministry approved cardiac surgeon Yoshiki Sawa at Osaka University to assess the safety of allogeneic iPSC-derived cardiomyocytes in patients with heart disease [47]. This research team has previously reported the efficacy of grafting of human iPSC-derived cardiomyocytes cell sheet in combination with an omental flap technique in a porcine model of ischemic cardiomyopathy [48, 49]. In the projected human trial, the treatment will initially be given to three people; then the team will seek approval to conduct a clinical trial in approximately 10 patients [47]. If these initial clinical studies prove successful, the treatment will be made commercially available soon after under a new fast-track system in Japan designed to speed up the development of regenerative therapies [47].

In October 2018, neurosurgeons at Kyoto University Hospital also performed the first iPSC cell-based therapy in patients with Parkinson's disease (https://www.kyotou.ac.jp/en/research/events\_news/department/hospital/news/2018/181109\_1.html). In this first human study, 2.4 million allogeneic iPSC-derived dopamine precursor cells were deposited into 12 sites of the patient's brain with known dopamine activity. At the time of the press conference on this procedure, November of 2018, the investigators described that the patient was "doing well." The human iPSC-derived progenitor cells have shown to improve the symptoms in a primate model of Parkinson's disease [50].

As compared to Japan's fast-forwarding pace of initiating human trials with iPSC-based therapies, the scientists and physicians in the United States are approaching this direction with more caution, even though several human ES cell-based therapies have been initiated in clinical studies [51]. For the treatment of Parkinson's disease, Lorenz Studer at Memorial Sloan Kettering Cancer Center has focused on generating dopamine neurons from human ES cells at a sufficient scale and purity and demonstrated their efficient engraftment and function in mouse, rat, and monkey models of Parkinson's disease [52]. Based on those results, the group is currently pursuing an investigational new drug (IND) application from the US Food and Drug Administration (FDA), to initiate the first human clinical use of ES cell-derived dopamine neurons [52]. In November 2018, Fate Therapeutics, Inc., a biopharmaceutical company, announced that the FDA approved their IND application for FT500, the company's universal NK cells derived from a clonal master iPSC line. Using an in vitro three-dimensional tumor spheroid model, the company demonstrated that FT500, in combination with activated T cells and an anti-programmed death (PD)-1 antibody, led to near-complete elimination of target cells (>99% reduction) [53]. The company plans to initiate first-in-human clinical testing of FT500 in combination with checkpoint inhibitor therapy for the treatment of advanced solid tumors. This is expected to be the first-ever clinical investigation in the United States of an iPSC-derived cell product.

In 2016, Cynata Therapeutics also launched a phase I clinical trial in both the United Kingdom (UK) and Australia using allogeneic iPSC-derived MSCs (differentiated from iPSCs through intermediate-stage mesenchymoangioblasts) (CYP-001) for the treatment of steroid-resistant acute graft-versus-host disease (aGvHD) in patients undergoing an allogenic stem cell transplantation. In 2018, the company reported that CYP-001 met all clinical endpoints and demonstrated positive safety and efficacy

*Innovations in Cell Research and Therapy*

ensure overall safety should be taken into account.

In 2014, Mandai et al. reported the results of the world's first clinical study of iPSCbased therapy in patients with advanced neovascular age-related macular degeneration (AMD) [45]. In this trial, two patients were recruited, and iPSCs were generated from the skin fibroblasts and were further differentiated into retinal pigment epithelial (RPE) cells [45]. One patient received the autologous iPSC-derived RPE cell sheet under the retina. A one-year follow-up on this patient revealed no apparent improvement nor worsening in her vision, and the transplanted sheet remained intact [45]. For the other patient, however, aberrations in DNA copy number were identified in the derived iPSCs and RPE cells, but not the starting fibroblasts, implying that genome mutations occurred during the reprogramming process [45]. This patient did not receive the treatment. Indeed, this clinical trial was suspended due to the

**2.7 Current clinical trials with iPSCs**

particularly for diseases that require an immediate treatment. For the clinical use of iPSC-based cell therapies, it is essential to produce high-quality and safe (no induced mutations in the genome) iPSCs. As will be mentioned below, the pioneering iPSC clinical study in Japan using patients' own iPSC-derived retinal epithelial cells for the treatment of macular degeneration was put on hold due to genomic mutations in the iPSCs. Therefore, the most feasible application of iPSC-based cell therapy would rely on the banked and human leukocyte antigen (HLA)-typed iPSCs, in which the quality and safety have been validated in advance, in the setting of an allogeneic transplantation. This use of allogenic iPSCs however means that immunosuppression would have to be applied to prevent immune rejection. Kawamura et al. recently demonstrated that even though the immunogenicity of allogenic iPSC-derived cardiomyocytes was reduced by major histocompatibility complex (MHC) class I- and class II-matched transplantation in the macaque (monkey), the recipients still required substantial and highly toxic immunosuppression for sustained allogeneic cell engraftment [40]. It has been suggested that the MHC-matched iPSC-derived cardiomyocytes were still susceptible to natural killer (NK) cell destruction, leading to their rejection in the recipients in the absence of immunosuppression [40]. Forced expression of HLA alpha chain E (HLA-E) in PSCs and their differentiated derivatives has been demonstrated to prevent allogeneic response and lysis by NK cells [41]. Recently, Deuse et al. looked into the expression of genes in syncytiotrophoblast, an interface between fetus and mother, and identified low MHC class I and II expression and a high CD47 expression as the features that are responsible for the immune tolerance of syncytiotrophoblast toward allogenic fetal antigens [42]. CD47 is a membrane protein that interacts with several cell surface receptors to inhibit phagocytosis [43]. Indeed, CD47 is a "don't eat me" signal highly expressed on the surface of cancer cells to escape the innate immune responses [44]. The authors then inactivated MHC class I and II genes through CRISPR-Cas9 targeting and overexpressed CD47 via lentiviral transduction in both human and mouse iPSCs [43]. Importantly, the engineered iPSCs and derivatives (endothelial cells, smooth muscle cells, and cardiomyocytes) lost their immunogenicity and persisted long term in fully MHC-mismatched recipients without the use of immunosuppression [43]. This suggests that hypoimmunogenic cell grafts can be engineered from iPSCs for universal transplantation without immunosuppression. These approaches are associated with potential risks of uncontrollable malignant transformation or impaired immune reactions using hypoimmunogenic cell grafts, and consideration of designing an inducible killing switch in the engineered cells to

**104**

data for the treatment of steroid-resistant aGvHD in a phase 1 trial. Cynata plans to advance the cell product into phase 2 trials for GvHD and critical limb ischemia.
