Ineke Slaper-Cortenbach

Applying extracellular vesicles based therapeutics in clinical trials - an ISEV position paper.

Extracellular vesicles (EVs), such as exosomes and microvesicles, are released by different cell types and participate in physiological and pathophysiological processes. EVs mediate intercellular communication as cell-derived extracellular signalling organelles that transmit specific information from their cell of origin to their target cells. As a result of these properties, EVs of defined cell types may serve as novel tools for various therapeutic approaches, including (a) anti-tumour therapy, (b) pathogen vaccination, (c) immune-modulatory and regenerative therapies and (d) drug delivery. The translation of EVs into clinical therapies requires the categorization of EV-based therapeutics in compliance with existing regulatory frameworks. As the classification defines subsequent requirements for manufacturing, quality control and clinical investigation, it is of major importance to define whether EVs are considered the active drug components or primarily serve as drug delivery vehicles. For an effective and particularly safe translation of EV-based therapies into clinical practice, a high level of cooperation between researchers, clinicians and competent authorities is essential. In this position statement, basic and clinical scientists, as members of the International Society for Extracellular Vesicles (ISEV) and of the European Cooperation in Science and Technology (COST) program of the European Union, namely European Network on Microvesicles and Exosomes in Health and Disease (ME-HaD), summarize recent developments and the current knowledge of EV-based therapies. Aspects of safety and regulatory requirements that must be considered for pharmaceutical manufacturing and clinical application are highlighted. Production and quality control processes are discussed. Strategies to promote the therapeutic application of EVs in future clinical studies are addressed.

Effect of Repetitive Intra-Arterial Infusion of Bone Marrow Mononuclear Cells in Patients With No-Option Limb Ischemia The Randomized, Double-Blind, Placebo-Controlled Rejuvenating Endothelial Progenitor Cells via Transcutaneous Intra-arterial Supplementation (JUVENTAS) Trial

Background —Patients with severe limb ischemia may not be eligible for conventional therapeutic interventions. Pioneering clinical trials suggest that bone marrow (BM)-derived cell therapy enhances neovascularization, improves tissue perfusion, and prevents amputation. The objective of this trial was to determine whether repetitive intra-arterial infusion of BM mononuclear cells (BMMNC) in patients with severe, non-revascularizable limb ischemia can prevent major amputation. Methods and Results —The Juventas-trial is a randomized, double-blind, placebo-controlled clinical trial in 160 patients with severe, non-revascularizable limb ischemia. Patients were randomized to repetitive (3x; 3-weeks interval) intra-arterial infusion of BMMNC or placebo. No significant differences were observed for the primary outcome, i.e. major amputation at 6 months, with major amputation rates of 19% in the BMMNC vs. 13% in the placebo group (Relative risk [RR] 1.46; 95% confidence interval [CI] 0.62 to 3.42). The safety outcome (all-cause mortality, occurrence of malignancy or hospitalization due to infection) was not significantly different between the groups (RR 1.46; 95%CI 0.63 to 3.38), neither was all-cause mortality at six months with 5% vs. 6% (RR 0.78; 95%CI 0.22 to 2.80). Secondary outcomes quality of life, rest pain, ankle-brachial index, and transcutaneous oxygen pressure improved during follow-up, but there were no significant differences between the groups. Conclusions —Repetitive intra-arterial infusion of autologous BMMNC into the common femoral artery did not reduce major amputation rate in patients with severe, non-revascularizable limb ischemia compared to placebo. The general improvement in secondary outcomes during follow-up in both the BMMNC as well as the placebo group underlines the essential role for placebo-controlled design of future trials. Clinical Trial Registration Information —ClinicalTrials.gov. Identifier: [NCT00371371][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00371371&atom=%2Fcirculationaha%2Fearly%2F2015%2F01%2F07%2FCIRCULATIONAHA.114.012913.atomBackground— Patients with severe limb ischemia may not be eligible for conventional therapeutic interventions. Pioneering clinical trials suggest that bone marrow–derived cell therapy enhances neovascularization, improves tissue perfusion, and prevents amputation. The objective of this trial was to determine whether repetitive intra-arterial infusion of bone marrow mononuclear cells (BMMNCs) in patients with severe, nonrevascularizable limb ischemia can prevent major amputation. Methods and Results— The Rejuvenating Endothelial Progenitor Cells via Transcutaneous Intra-arterial Supplementation (JUVENTAS) trial is a randomized, double-blind, placebo-controlled clinical trial in 160 patients with severe, nonrevascularizable limb ischemia. Patients were randomly assigned to repetitive (3 times; 3-week interval) intra-arterial infusion of BMMNC or placebo. No significant differences were observed for the primary outcome, ie, major amputation at 6 months, with major amputation rates of 19% in the BMMNC versus 13% in the placebo group (relative risk, 1.46; 95% confidence interval, 0.62–3.42). The safety outcome (all-cause mortality, occurrence of malignancy, or hospitalization due to infection) was not significantly different between the groups (relative risk, 1.46; 95% confidence interval, 0.63–3.38), neither was all-cause mortality at 6 months with 5% versus 6% (relative risk, 0.78; 95% confidence interval, 0.22–2.80). Secondary outcomes quality of life, rest pain, ankle-brachial index, and transcutaneous oxygen pressure improved during follow-up, but there were no significant differences between the groups. Conclusions— Repetitive intra-arterial infusion of autologous BMMNCs into the common femoral artery did not reduce major amputation rates in patients with severe, nonrevascularizable limb ischemia in comparison with placebo. The general improvement in secondary outcomes during follow-up in both the BMMNC and the placebo group, as well, underlines the essential role for placebo-controlled design of future trials. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00371371.

Introduction of a Quality Management System and Outcome After Hematopoietic Stem-Cell Transplantation

PURPOSE A comprehensive quality management system called JACIE (Joint Accreditation Committee International Society for Cellular Therapy and the European Group for Blood and Marrow Transplantation), was introduced to improve quality of care in hematopoietic stem-cell transplantation (HSCT). We therefore tested the hypothesis that the introduction of JACIE improved patient survival. PATIENTS AND METHODS Data on 41,623 allogeneic (39%) and 66,281 autologous (61%) HSCTs for an acquired hematologic disorder performed between 1999 and 2007 by 421 teams in Europe were used to assess the outcomes of patients who received a transplantation at baseline (> 3 years before application or no application), during preparation (3 years before application), during application (time from application to accreditation), and after JACIE accreditation. The analysis was clustered by team and stratified for year of HSCT, donor type, disease, conditioning, and gross national income per capita of the respective country. Patients risks were adjusted for by their European Group for Blood and Marrow Transplantation score. RESULTS Patient outcome was systematically better when the transplantation center was at a more advanced phase of JACIE accreditation, independent of year of transplantation and other risk factors. Improvement was robust as quantified for relapse-free survival after allogeneic HSCT compared with baseline by a hazard ratio (HR) of 0.96 (95% CI, 0.90 to 1.03; P = .22) for preparation, 0.95 (95% CI, 0.88 to 1.03; P = .20) for application, and 0.86 (95% CI, 0.78 to 0.95; P = .01) for the accreditation (test for trend P = .01). Improvement from baseline was similar after autologous HSCT (HR for accreditation, 0.83; 95% CI, 0.74 to 0.93; P < .01). CONCLUSION Even with all the limitations of an observational study, these findings support the hypothesis that introduction of a comprehensive clinical quality management system is associated with improved outcome of patients after HSCT.

Effect of Repetitive Intra-Arterial Infusion of Bone Marrow Mononuclear Cells in Patients With No-Option Limb Ischemia: The Randomized, Double-Blind, Placebo-Controlled JUVENTAS Trial

Background —Patients with severe limb ischemia may not be eligible for conventional therapeutic interventions. Pioneering clinical trials suggest that bone marrow (BM)-derived cell therapy enhances neovascularization, improves tissue perfusion, and prevents amputation. The objective of this trial was to determine whether repetitive intra-arterial infusion of BM mononuclear cells (BMMNC) in patients with severe, non-revascularizable limb ischemia can prevent major amputation. Methods and Results —The Juventas-trial is a randomized, double-blind, placebo-controlled clinical trial in 160 patients with severe, non-revascularizable limb ischemia. Patients were randomized to repetitive (3x; 3-weeks interval) intra-arterial infusion of BMMNC or placebo. No significant differences were observed for the primary outcome, i.e. major amputation at 6 months, with major amputation rates of 19% in the BMMNC vs. 13% in the placebo group (Relative risk [RR] 1.46; 95% confidence interval [CI] 0.62 to 3.42). The safety outcome (all-cause mortality, occurrence of malignancy or hospitalization due to infection) was not significantly different between the groups (RR 1.46; 95%CI 0.63 to 3.38), neither was all-cause mortality at six months with 5% vs. 6% (RR 0.78; 95%CI 0.22 to 2.80). Secondary outcomes quality of life, rest pain, ankle-brachial index, and transcutaneous oxygen pressure improved during follow-up, but there were no significant differences between the groups. Conclusions —Repetitive intra-arterial infusion of autologous BMMNC into the common femoral artery did not reduce major amputation rate in patients with severe, non-revascularizable limb ischemia compared to placebo. The general improvement in secondary outcomes during follow-up in both the BMMNC as well as the placebo group underlines the essential role for placebo-controlled design of future trials. Clinical Trial Registration Information —ClinicalTrials.gov. Identifier: [NCT00371371][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00371371&atom=%2Fcirculationaha%2Fearly%2F2015%2F01%2F07%2FCIRCULATIONAHA.114.012913.atomBackground— Patients with severe limb ischemia may not be eligible for conventional therapeutic interventions. Pioneering clinical trials suggest that bone marrow–derived cell therapy enhances neovascularization, improves tissue perfusion, and prevents amputation. The objective of this trial was to determine whether repetitive intra-arterial infusion of bone marrow mononuclear cells (BMMNCs) in patients with severe, nonrevascularizable limb ischemia can prevent major amputation. Methods and Results— The Rejuvenating Endothelial Progenitor Cells via Transcutaneous Intra-arterial Supplementation (JUVENTAS) trial is a randomized, double-blind, placebo-controlled clinical trial in 160 patients with severe, nonrevascularizable limb ischemia. Patients were randomly assigned to repetitive (3 times; 3-week interval) intra-arterial infusion of BMMNC or placebo. No significant differences were observed for the primary outcome, ie, major amputation at 6 months, with major amputation rates of 19% in the BMMNC versus 13% in the placebo group (relative risk, 1.46; 95% confidence interval, 0.62–3.42). The safety outcome (all-cause mortality, occurrence of malignancy, or hospitalization due to infection) was not significantly different between the groups (relative risk, 1.46; 95% confidence interval, 0.63–3.38), neither was all-cause mortality at 6 months with 5% versus 6% (relative risk, 0.78; 95% confidence interval, 0.22–2.80). Secondary outcomes quality of life, rest pain, ankle-brachial index, and transcutaneous oxygen pressure improved during follow-up, but there were no significant differences between the groups. Conclusions— Repetitive intra-arterial infusion of autologous BMMNCs into the common femoral artery did not reduce major amputation rates in patients with severe, nonrevascularizable limb ischemia in comparison with placebo. The general improvement in secondary outcomes during follow-up in both the BMMNC and the placebo group, as well, underlines the essential role for placebo-controlled design of future trials. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00371371.

A randomized multicenter comparison of CD34+-selected progenitor cells from blood vs from bone marrow in recipients of HLA-identical allogeneic transplants for hematological malignancies

OBJECTIVE Peripheral blood progenitor cells (PBPC) have been established as an alternative source of hematopoietic stem cells for allogeneic transplantation, but an increased incidence of both acute and chronic graft-vs-host disease (GVHD) has become apparent. We performed a prospective randomized trial comparing bone marrow transplantation (BMT) vs PBPC transplantation (PBPCT) using CD34(+) selection for T-cell depletion (TCD) in both study arms. PATIENTS AND METHODS Between January 1996 and October 2000, 120 patients with a diagnosis of acute leukemia, myelodysplasia, multiple myeloma, or lymphoma were randomized to receive either filgrastim-mobilized PBPC or BM from HLA-identical sibling donors after standard high-dose chemoradiotherapy. Patient characteristics did not differ between study arms. RESULTS Recipients of PBPC received more CD3(+) T cells (median: 3.0 vs 2.0 x 10(5)/kg, p<0.0001) and more CD34(+) cells (median: 3.6 vs 0.9 x 10(6)/kg, p<0.0001). Neutrophil and platelet recoveries occurred significantly faster after PBPCT. The cumulative incidence of acute GVHD grades II-IV was 37% after BMT vs 52% after PBPCT and was most significantly (p=0.007) affected by the number of CD3(+) T cells in the graft. Acute GVHD appeared strongly associated with increased treatment-related mortality (TRM) in a time-dependent analysis. Higher numbers of CD34(+) cells were associated with less TRM. With a median follow-up of 37 months (range: 12-75), overall survival at 4 years from transplantation was 60% after BMT and 34% for recipients of PBPCT (p=0.04), which difference was largely due to increased GVHD and TRM in PBPC recipients receiving T-cell dosages greater than 2 x 10(5)/kg. CONCLUSION Outcome following T cell-depleted PBPCT critically depends on the number of CD3(+) T cells, whereby high T-cell numbers may blunt a favorable effect of higher CD34(+) cell numbers.

Allogeneic Mesenchymal Stem Cells Stimulate Cartilage Regeneration and Are Safe for Single‐Stage Cartilage Repair in Humans upon Mixture with Recycled Autologous Chondrons

Traditionally, mesenchymal stem cells (MSCs) isolated from adult bone marrow were described as being capable of differentiating to various lineages including cartilage. Despite increasing interest in these MSCs, concerns regarding their safety, in vivo behavior and clinical effectiveness have restrained their clinical application. We hypothesized that MSCs have trophic effects that stimulate recycled chondrons (chondrocytes with their native pericellular matrix) to regenerate cartilage. Searching for a proof of principle, this phase I (first‐in‐man) clinical trial applied allogeneic MSCs mixed with either 10% or 20% recycled autologous cartilage‐derived cells (chondrons) for treatment of cartilage defects in the knee in symptomatic cartilage defect patients. This unique first in man series demonstrated no treatment‐related adverse events up to one year postoperatively. At 12 months, all patients showed statistically significant improvement in clinical outcome compared to baseline. Magnetic resonance imaging and second‐look arthroscopies showed completely filled defects with regenerative cartilage tissue. Histological analysis on biopsies of the grafts indicated hyaline‐like regeneration with a high concentration of proteoglycans and type II collagen. Short tandem repeat analysis showed the regenerative tissue only contained patient‐own DNA. These findings support the novel insight that the use of allogeneic MSCs is safe and opens opportunities for other applications. Stem cell‐induced paracrine mechanisms may play an important role in the chondrogenesis and successful tissue regeneration found. Stem Cells 2017;35:256–264

Autologous, allogeneic, induced pluripotent stem cell or a combination stem cell therapy? Where are we headed in cartilage repair and why: a concise review

The evolution of articular cartilage repair procedures has resulted in a variety of cell-based therapies that use both autologous and allogeneic mesenchymal stromal cells (MSCs). As these cells are increasingly available and show promising results both in vitro and in vivo, cell-based strategies, which aim to improve ease of use and cost-effectiveness, are progressively explored. The use of MSCs in cartilage repair makes it possible to develop single-stage cell-based therapies. However, true single-stage procedures rely on one intervention, which will limit cell sources to fraction concentrates containing autologous MSCs or culture-expanded allogeneic MSCs. So far, it seems both autologous and allogeneic cells can safely be applied, but clinical studies are still ongoing and little information on clinical outcome is available. Further development of cell-based therapies may lead to clinical-grade, standardized, off-the-shelf products with easy handling for orthopedic surgeons. Although as of yet no preclinical or clinical studies are ongoing which explore the use of induced pluripotent stem cells for cartilage repair, a good manufacturing practice-grade induced pluripotent stem cell line might become the basis for such a product in the future, providing that cell fate can be controlled. The use of stem cells in clinical trials brings along new ethical issues, such as proper controls and selecting primary outcome measures. More clinical trials are needed to estimate detailed risk-benefit ratios and trials must be carefully designed to minimize risks and burdens for patients while choosing outcome measures that allow for adequate comparison with results from similar trials. In this review, we discuss the different aspects of new stem cell-based treatments, including safety and ethical issues, as well as provide an overview of current clinical trials exploring these approaches and future perspectives.

Biomarker profiling of steroid-resistant acute GVHD in patients after infusion of mesenchymal stromal cells

We performed a prospective phase II study to evaluate clinical safety and outcome in 48 patients with steroid-refractory grade II–IV acute graft-versus-host disease (aGVHD) treated with mesenchymal stromal cells (MSCs). Clinical outcomes were correlated to comprehensive analyses of soluble and cellular biomarkers. Complete resolution (CR) of aGVHD at day 28 (CR-28) occurred in 12 (25%) patients, CR lasting >1 month (CR-B) occurred in 24 (50%) patients. One-year overall survival was significantly improved in CR-28 (75 versus 33%, P=0.020) and CR-B (79 versus 8%, P<0.001) versus non-CR patients. A six soluble biomarker-panel was predictive for mortality (HR 2.924; CI 1.485–5.758) when measured before MSC-administration. Suppression of tumorigenicity 2 (ST2) was only predictive for mortality 2 weeks after but not before MSC-administration (HR 2.389; CI 1.144–4.989). In addition, an increase in immature myeloid dendritic cells associated with decreased mortality (HR 0.554, CI 0.389–0.790). Patients had persisting T-cell responses against defined virus- and leukemia-associated antigens. In conclusion, our data emphasize the need to carefully assess biomarkers in cohorts with homogeneous GVHD treatments. Biomarkers might become an additional valuable component of composite end points for the rapid and efficient testing of novel compounds to decrease lifecycle of clinical testing and improve the success rate of phase II/III trials.

Intranasal Administration of Human MSC for Ischemic Brain Injury in the Mouse: In Vitro and In Vivo Neuroregenerative Functions

Intranasal treatment with C57BL/6 MSCs reduces lesion volume and improves motor and cognitive behavior in the neonatal hypoxic-ischemic (HI) mouse model. In this study, we investigated the potential of human MSCs (hMSCs) to treat HI brain injury in the neonatal mouse. Assessing the regenerative capacity of hMSCs is crucial for translation of our knowledge to the clinic. We determined the neuroregenerative potential of hMSCs in vitro and in vivo by intranasal administration 10 d post-HI in neonatal mice. HI was induced in P9 mouse pups. 1×106 or 2×106 hMSCs were administered intranasally 10 d post-HI. Motor behavior and lesion volume were measured 28 d post-HI. The in vitro capacity of hMSCs to induce differentiation of mouse neural stem cell (mNSC) was determined using a transwell co-culture differentiation assay. To determine which chemotactic factors may play a role in mediating migration of MSCs to the lesion, we performed a PCR array on 84 chemotactic factors 10 days following sham-operation, and at 10 and 17 days post-HI. Our results show that 2×106 hMSCs decrease lesion volume, improve motor behavior, and reduce scar formation and microglia activity. Moreover, we demonstrate that the differentiation assay reflects the neuroregenerative potential of hMSCs in vivo, as hMSCs induce mNSCs to differentiate into neurons in vitro. We also provide evidence that the chemotactic factor CXCL10 may play an important role in hMSC migration to the lesion site. This is suggested by our finding that CXCL10 is significantly upregulated at 10 days following HI, but not at 17 days after HI, a time when MSCs no longer reach the lesion when given intranasally. The results described in this work also tempt us to contemplate hMSCs not only as a potential treatment option for neonatal encephalopathy, but also for a plethora of degenerative and traumatic injuries of the nervous system.

JACIE accreditation in 2008: demonstrating excellence in stem cell transplantation.

JACIE was initiated as a small pilot project in Spain in 2000 and launched as a formal Europe-wide inspection program in January 2004. Since 2000, over 150 applications for accreditation have been received by the JACIE Office and more than 130 inspections have been completed in European centers and facilities. Almost all of these were found to be functioning at a high level of excellence, with the majority having only minor deficiencies in compliance with the standards. In one-third of centers there were more significant deficiencies. The most common deficiencies were in quality management. Following correction of deficiencies 86 centers have to date achieved full accreditation and many more are nearing the completion of the process. Implementation of JACIE involves a significant investment of time and resources by applicant centers. The majority require at least 18 months to prepare for accreditation and 85% have needed to employ a quality manager and/or data manager on an ongoing basis. However, all centers felt their program had benefited from the implementation of JACIE. JACIE is also working closely with other international organisations related to cellular therapy as part of the Alliance for the Harmonisation of Cell Therapy Accreditation (AHCTA), which is examining the differences in existing standards and aiming to develop international standards for all aspects of stem cell transplantation. In particular the requirements for safety of imported tissues and cells has emphasised the need for global harmonisation. The recent implementation of Directive 2004/23/EC and the associated Commission Directives 2006/17/EC and 2006/86/EC has provided an impetus for the implementation of JACIE in European Union (EU) member states. It will be important in the future to examine how JACIE can co-operate with the EU Competent Authorities (CA) to ease the burden of the inspection process for haemopoietic stem cell (HSC) transplant programs.