Gamida Cell Announces First Patient with Sickle Cell Disease Transplanted in Phase 1/2 Study of CordIn™ as the Sole Graft Source

An Israeli regenerative therapy company called Gamida Cell specializes in cellular and immune therapies to treat cancer and rare (“orphan”) genetic diseases. Gamida Cell’s main product is called NiCord, which provides patients who need new blood-making stem cells in their bone marrow an alternative to a bone marrow transplant. NiCord is umbilical cord blood that has been expanded in culture. In clinical trials to date, NiCord has rapidly engrafted into patients and the clinical outcomes of NiCord transplantation seem to be comparable to transplantation of peripheral blood.

Gamida Cell’s two products, NiCord and CordIn, as well as some other products under development utilize the company’s proprietary NAM platform technology to expand umbilical cord cells. The NAM platform technology has the remarkable capacity to preserve and enhance the functionality of hematopoietic stem cells from umbilical cord blood. CordIn is an experimental therapy for those rare non-malignant diseases in which bone marrow transplantation is the only currently available cure.

Gamida Cell has recently announced that the first patient with sickle cell disease (SCD) has been transplanted with their CordIn product.  Mark Walters, MD, Director of the Blood and Marrow Transplantation (BMT) Program is the Principal Investigator of this clinical trial. The patient received their transplant at UCSF Benioff Children’s Hospital Oakland.

CordIn, as previously mentioned, is an experimental therapy for rare non-malignant diseases, including hemoglobinopathies such as Sickel Cell Disease and thalassemia, bone marrow failure syndromes such as aplastic anemia, genetic metabolic diseases and refractory autoimmune diseases. CordIn potentially addresses a presently unmet medical need.

“The successful enrollment and transplantation of our first SCD patient with CordIn as a single graft marks an important milestone in our clinical development program. We are eager to demonstrate the potential of CordIn as a transplantation solution to cure SCD and to broaden accessibility to patients with rare genetic diseases in need of bone marrow transplantation,” said Gamida Cell CEO Dr. Yael Margolin. “In the first Phase 1/2 study with SCD, the expanded graft was transplanted along with a non-manipulated umbilical cord blood unit in a double graft configuration. In the second phase 1/2 study we updated the protocol from our first Phase 1/2 study so that patients would be transplanted with CordIn as a standalone graft, which is expanded from one full umbilical cord blood unit and enriched with stem cells using the company’s proprietary NAM technology.”

Somewhere in the vicinity of 100,000 patients in the U.S suffer from SCD; and around 200,000 patients suffer from thalassemia, globally. The financial burden of treating these patients over their lifetime is estimated at $8-9M. Bone marrow transplantation is the only clinically established cure for SCD, but only a few hundred SCD patients have actually received a bone marrow transplant in the last ten years, since most patients were not successful in finding a suitable match. Unrelated cord blood could be available for most of the patients eligible for transplantation, but, unfortunately, the rate of successful engraftment of un-expanded cord blood in these patients is low. Therefore, cord blood is usually not considered for SCD patients. Without a transplant, these patients suffer from very high morbidity and low quality of life.

Eight patients with SCD were transplanted in the first Phase 1/2 study performed in a double graft configuration. This study is still ongoing. Preliminary data from the first study will be summarized and published later this year. A Phase 1/2 of CordIn for the treatment of patients with aplastic anemia will commence later this year.

Umbilical Cord Blood Mesenchymal Stem Cells do Not Cause Tumors in Rigorous Tests

Human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) have the ability to self-renew and also can differentiate into a wide range of cell types. However, many clinicians and scientists fear that even these very useful cells might cause tumors.

To that end, Moon and colleagues from the Korean Institute of Toxicology have rigorously tested the tendency for hUBC-MSCs to cause tumors. They used a large battery of tests in living organisms and in culture. hUCB-MSCs were compared to MRC-5 and HeLa cells. MRC-5 cells are known to have no ability to cause tumors and HeLa cells have a robust ability to form tumors, and therefore, constitute negative and positive controls,

To evaluate the ability of cells to cause tumors, Moon and others examined the tendency of these cells to grow without being attached to a substratum. This is a hallmark of tumor cells and is called “anchorage-independent growth” (AIG). To assess AIG, the cells were grown in soft agar, which is a standard assay for AIG. hUCB-MSCs and MRC-5 cells formed few colonies in soft agar, but HeLa cells formed a greater number of larger colonies. This indicated that hUCB-MSCs and MRC-5 cells do not show AIG, a common trait of tumorigenic cells.

The next assay implanted these cells into live laboratory animals. hUCB-MSCs were implanted as a underneath the skin of BALB/c-nu mice (nasty creatures – they bite). All the mice implanted with hUCB-MSCs and NRC-5 cells showed any sign of tumors. Both gross and microscopic examination failed reveal any tumors. However, all mice transplanted with HeLa cells developed tumors that were clearly derived from the implanted cells.

These experiments, though somewhat mundane, rigorously demonstrate that hUCB-MSCs do not exhibit tumorigenic potential. This provides further evidence of these cells clinical applications.

The paper appeared in Toxicol Res. 2016 Jul;32(3):251-8. doi: 10.5487/TR.2016.32.3.251.

Gamida Cell Phase 3 Study Design Outline Approved by FDA and EMA

Gamida Cell, a cell therapy company based in Jerusalem, Israel, has reached agreements with the US Food and Drug Administration (USFDA) and the European Medicines Agency (EMA) with regards to a Phase III study design outline for testing their NiCord product. NiCord is a blood cancer treatment derived from a single umbilical cord blood until expanded in culture and enriched with stem cells by means of the company’s proprietary NAM technology.

Gamida Cell is moving forward now with plans to commence an international, multi-center, Phase III study of NiCord in 2016. Phase I/II data of 15 patients are expected in the fourth quarter of 2015. NiCord is in development as an experimental treatment for various types of blood cancers including Acute Myeloid Leukemia (AML), Acute Lymphoblastic Leukemia (ALL), Myelodysplastic Syndrome (MDS), and Chronic Myelogenous Leukemia (CML).

NiCord® is derived from a single cord blood unit which has been expanded in culture and enriched with stem cells using Gamida Cell’s proprietary NAM technology. NAM technology proceeds from the observation that nicotinamide, a form of vitamin B3, inhibits the loss of functionality that usually occurs during the culture process of umbilical cord blood stem cells, when added to the culture medium. Pre-clinical studies have also shown that the expanded cell grafts manufactured using NAM technology demonstrate improved functionality following infusion in a living animal. These stem cells show improved movement, home to the bone marrow, and show higher rates of engraftment, or durable retention in the bone marrow. Based on these results, Gamida Cell is currently testing in clinical trials (in patients) cells expanded in culture with the NAM platform to determine their safety and effectiveness as a treatment for blood cancers, sickle-cell anemia and thalassemia. NiCord is intended to fill the crucial clinical need for a treatment for the vast majority of blood cancer patients indicated for bone marrow transplantation, with insufficient treatment options. This segment has a multi-billion dollar market potential.

“The FDA and EMA feedback is a major regulatory milestone for NiCord. NiCord is a life-saving therapy intended to provide a successful treatment for the large number of blood cancer patients who do not have a family related matched donor. Gamida Cell is dedicated to changing the paradigm in transplantation by bringing this therapy to market as soon as possible,” said Dr. Yael Margolin, president and CEO of Gamida Cell.

“The positive regulatory feedback confirms that Gamida Cell’s NiCord program is on a clear path to approval both in the U.S. and EU. We look forward to continuing the development of this very important product in cooperation with sites of excellence in cord blood transplantation worldwide,” said Dr. David Snyder, V.P. of Clinical Development and Regulatory Affairs at Gamida Cell.

The Phase III study will be a randomized, controlled study of approximately 120 patients. It will compare the outcomes of patients transplanted with NiCord to those of patients transplanted with un-manipulated umbilical cord blood.


Umbilical Cord Blood and Bone Marrow Transplants in Myelodysplastic Syndrome

Myelodysplasia syndrome (MDS) killed my mother. Therefore, this paper caught my eye.

This paper describes a multicenter study from Argentina that examined children with MDS. MDS affects the blood cell-producing stem cells in the bone marrow so that these cells make immature red blood cells that do not properly carry oxygen to tissues. The rogue stem cells produce droves and droves of these immature cells that overpopulate the bone marrow and crowd out the normal bone marrow stem cells. Patients with MDS suffer shortness of breath, weakness and fatigue, mental lapses, and other symptoms of anemia.  They also must rely on blood transfusions in order to keep them alive. Bone marrow transplants or umbilical cord transplants can cure MDS patients.

In this study, Ana Basquiera, from the Hospital Privado Centro Médico de Córdoba, Argentina, and her colleagues evaluated the overall survival, disease-free survival (DFS), non-relapse mortality (NRM) and relapse incidence in MDS children who underwent bone marrow and umbilical cord transplants. These children received these transplants in six different clinical throughout Argentina. All in all, 54 transplants were conducted in 52 patients. The mean age of these patients was 9 years old (range: 2–19), and 35 of the patients were males.

Several different types of MDS were seen in these patients, but all of them were not treatable by other means. Because MDS often precedes leukemia, seven (13%) patients at the time of the transplant transformed to acute myeloid leukemia (AML) and the diagnosis of two other patients also worsened.

All patients had their own bone marrow wiped out by means of a “conditioning regimen.” These are drugs that destroy the bone marrow stem cells of the patient and leave them without the means of make their own red blood cells or immune cells. Patients must then receive high doses of antibiotics and anti-fungal drugs while their bone marrow is repopulated. As you can guess, this is a nasty, dangerous procedure.

Of these patients, 63% received bone marrow stem cells, 26% stem cells from peripheral blood, and 11% umbilical cord blood. Five-year disease-free survival and overall survival were 50% and 55% respectively; and for patients with juvenile myelomonocytic leukemia, 57% and 67% respectively.

Cumulative incidence of non-relapse mortality and relapse were 27% and 21% respectively. Statistical analyses of the data from these treatments showed that patients who had received umbilical cord blood (HR 4.07; P = 0.025) and were younger than nine years old tended to have a lower overall survival rate. Also, younger patients who experienced graft-versus-host disease (GVHD), in which the engrafted immune cells begin to attack the tissues of the patient, had a higher rate of non-relapse mortality (no real surprise there).

Thus, more than half of the patients achieved long-term overall survival. The mortality and relapse rates were rather high, however, and it is possible that less toxic conditioning regimens or more intensive prevention of GVHD could lead to better results in some children. Until such procedures are make available, such mortality rates will probably remain high, even though the procedure does potentially cure the patients of MDS.  Thus this remains a “high risk, big pay-off” procedure.

This was published in Pediatric Blood and Cancer.

Engineered Neural Stem Cells Deliver Anti-Cancer Drug to the Brain

Irinotecan is an anticancer drug that was approved for use in 1996. It is a modified version of the plant alkaloid camptothecin, and even though it shows significant activity against brain tumors in culture, but in a living body, this drug poorly penetrates the blood-brain barrier. Therefore irinotecan usually does not accumulate to appreciable levels in the brain and is typically not used to treat brain tumors.

That could change, however, if a new strategy published in paper by Marianne Metz and her colleagues from the laboratory of Karen Aboody at the Beckman Research Institute at the City of Hope in Duarte, California, in collaboration with colleagues from several other laboratories.

In this paper, Metz and her co-workers genetically engineered neural stem cells to express enzymes called “carboxylesterases.” These carboxyesterase enzymes convert irinotecan, which is an inactive metabolite, to the active form, which is known as “SN-38.” The efficient conversion of irinotecan to SN-38 in the brain greatly accelerates the therapeutic activity of this drug in the brain. Also, the constant conversion of irinotecan to another molecule accelerates the transport of irinotecan past the blood brain barrier.

To test this strategy. Metz and others grew the engineered neural stem cells in culture and measured their ability to make carboxylesterases in culture, and their ability to convert irinotecan into SN-38 in culture.  In both cases, the engineered neural stem cells made a boat-load of carboxylesterase and converted irinotecan into SN-38 in spades.  More importantly, the genetically engineered neural stem cells behaved exactly as they did before, which shows that the genetic manipulation of these cells did not change their properties.

Next, Metz others tested the ability of the engineered neural stem cells to kill human brain tumor cells in culture in the presence of irinotecan.  Once again, the genetically engineered neural stem cells effectively killed human brain tumor cells in culture in a irinotecan-concentration-dependent manner.  When these genetically engineered neural stem cells were injected into the brains of mice with brain tumors, intravenous administration of irinotecan produced high levels of SN-38 in the brain.  This shows that these cells have the capacity to increase the production of SN-38 in the brain.

This strategy is similar to other strategies that been used in various clinical trials, but because neural stem cells have a tendency to move into brain tumor tissue and surround it, they represent an efficient and effective way to deliver anticancer drugs to brain tumors.  Also, since the particular neural stem cell line used in this experiment (HB1.F3.CD) does not cause tumors and is also not recognized as foreign by the immune system, it is a particularly attractive stem cell line for such an anti-tumor strategy.

Preventing the Rejection of Embryonic Stem Cell Derivatives – Take Two

Yesterday I blogged about the paper from Yang Xu’s group that used genetically engineered embryonic stem cells to make adult cell types that were not rejected by the immune systems of mice with humanized immune systems. I would like to say a bit more about this paper before I leave it be.

First of all, Xu and his colleagues engineered the cells to express the cell-surface protein PD-L1, which stands for programmed cell death ligand 1 (also known as CD274), and another protein called CTLA4-Ig. The combination of these two proteins tends to make these cells invisible to the immune system for all practical intents and purposes.

PD-L1, however, is used by tumor cells to evade detection by the immune system. For example, increased expression of PD-L1 is highly correlated with the aggressiveness of the cancer. One particular experiment examined 196 tumor specimens that had been extracted from patients with renal cell carcinoma (kidney tumors). In these tumor samples, high expression of PD-L1 was positively associated with increased tumor aggressiveness and a those patients that had higher expression of PD-L1 have a 4.5-fold increased risk of death (see Thompson RH, et al., Proc Natl Acad Sci USA 101 (49): 17174–9). In patients with cancer of the ovaries, those tumors with higher PD-L1 expression had a significantly poorer prognosis than those with lower PD-L1 expression. The more PD-L1 these tumors expressed, the fewer tumor-hunting T cells (CD8+ T cells) were present (see Hamanishi J, and others, Proc Natl Acad Sci USA 104 (9): 3360–5).

So the Xu paper proposes that we introduce genetically engineered cells, which are already at risk for mutations in the first place, into the body, that constitutively express PD-L1, a protein known to be highly expressed in the most aggressive and lethal tumors. Does this sound like a good idea?

With respect to CTLA4-Ig, this is a cell-bound version of a drug that has been approved as an anti-transplantation rejection drug called Belatacept (Nulojix), made by Bristol-Myers-Squibb. Since this is a cell-bound version of this protein, it will almost certainly not have the systemic effects of Belatacept, and if the cells manage to release a certain amount of soluble CTLA4-Ig, it is likely to be very little and have no biological effect.

Therefore, this strategy, while interesting, does come with its own share of risks and caveats.

Regenerating Injured Kidneys with Exosomes from Human Umbilical Cord Mesenchymal Stem Cells

Zhou Y, Xu H, Xu W, Wang B, Wu H, Tao Y, Zhang B, Wang M, Mao F, Yan Y, Gao S, Gu H, Zhu W, Qian H: Exosomes released by human umbilical cord mesenchymal stem cells protect against cisplatin-induced renal oxidative stress and apoptosis in vivo and in vitro. Stem Cell Res Ther 2013, 4:34.

Ying Zhou and colleagues from Jiangsi University have provided helpful insights into how adult stem cell populations – in particular, mesenchymal stem cells (MSCs) isolated from human umbilical cord (hucMSCs) – are able to regulate tissue repair and regeneration. Adult stem cells, including MSCs from different sources, confer regenerative effects in animal models of disease and tissue injury. Many of these cells are also in phase I and II trials for limb ischemia, congestive heart failure, and acute myocardial infarction (Syed BA, Evans JB. Nat Rev Drug Discov 2013, 12:185–186).

Despite the documented healing capabilities of MSCs, in many cases, even though the implanted stem cells produce genuine, reproducible therapeutic effects, the presence of the transplanted stem cells in the regenerating tissue is not observed. These observations suggest that the predominant therapeutic effect of stem cells is conferred through the release of therapeutic factors. In fact, conditioned media from adult stem cell populations are able to improve ischemic damage to kidney and heart, which confirms the presence of factors released by stem cells in mediating tissue regeneration after injury (van Koppen A, et al., PLoS One 2012, 7:e38746; Timmers L, et al., Stem Cell Res 2007, 1:129–137). Additionally, the secretion of factors such as interleukin-10 (IL-10), indoleamine 2,3-dioxygenase (IDO), interleukin-1 receptor antagonist (IL-1Ra), transforming growth factor-beta 1 (TGF-β1), prostaglandin E2 (PGE2), and tumor necrosis factor-alpha-stimulated gene/protein 6 (TSG-6) has been implicated in conferring the anti-inflammatory effects of stem cells (Pittenger M: Cell Stem Cell 2009, 5:8–10). These observations cohere with the positive clinical effects of MSCs in treating Crohn’s disease and graft-versus-host disease (Caplan AI, Correa D. Cell Stem Cell 2011, 9:11–15).

Another stem cell population called muscle-derived stem/progenitor cells, which are related to MSCs, can also extend the life span of mice that have the equivalent of an aging disease called progeria. These muscle-derived stem/progenitor cells work through a paracrine mechanism (i.e. the release of locally acting substances from cells; see Lavasani M, et al., Nat Commun 2012, 3:608). However, it is unclear what factors released by functional stem cells are important for facilitating tissue regeneration after injury, disease, or aging and the precise mechanism through which these factors exert their effects. Recently, several groups have demonstrated the potent therapeutic activity of small vesicles called exosomes that are released by stem cells (Gatti S, et al., Nephrol Dial Transplant 2011, 26:1474–1483; Bruno S, et al., PLoS One 2012, 7:e33115; Lai RC, et al., Regen Med 2013, 8:197–209; Lee C, et al., Circulation 2012, 126:2601–2611; Li T, et al., Stem Cells Dev 2013, 22:845–854). Exosomes are a type of membrane vesicle with a diameter of 30 to 100 nm released by most cell types, including stem cells. They are formed by the inverse budding of the multivesicular bodies and are released from cells upon fusion of multivesicular bodies with the cell membrane (Stoorvogel W, et al., Traffic 2002, 3:321–330).

Exosomes are distinct from larger vesicles, termed ectosomes, which are released by shedding from the cell membrane. The protein content of exosomes depends on the cells that release them, but they tend to be enriched in certain molecules, including adhesion molecules, membrane trafficking molecules, cytoskeleton molecules, heat-shock proteins, cytoplasmic enzymes, and signal transduction proteins. Importantly, exosomes also contain functional mRNA and microRNA molecules. The role of exosomes in vivo is hypothesized to be for cell-to-cell communication, transferring proteins and RNAs between cells both locally and at a distance.

To examine the regenerative effects of MSCs derived from human umbilical cord, Zhou and colleagues used a rat model of acute kidney toxicity induced by treatment with the anti-cancer drug cisplatin. After treatment with cisplatin, rats show increases in blood urea nitrogen and creatinine levels (a sign of kidney dysfunction) and increases in apoptosis, necrosis, and oxidative stress in the kidney. If exosomes purified from hucMSCs, termed hucMSC-ex are injected underneath the renal capsule into the kidney, these indices of acute kidney injury decrease. In cell culture, huc-MSC-exs promote proliferation of rat renal tubular epithelial cells in culture. These results suggest that hucMSC-exs can reduce oxidative stress and programmed cell death, and promote proliferation. What is not clear is how these exosomes pull this off. Zhou and colleagues provide evidence that hucMSC-ex can reduce levels of the pro-death protein Bax and increase the pro-survival Bcl-2 protein levels in the kidney to increase cell survival and stimulate Erk1/2 to increase cell proliferation.

Another research group has reported roles for miRNAs and antioxidant proteins contained in stem cell-derived exosomes for repair of damaged renal and cardiac tissue (Cantaluppi V, et al., Kidney Int 2012, 82:412–427). In addition, MSC exosome-mediated delivery of glycolytic enzymes (the pathway that degrades sugar) to complement the ATP deficit in ischemic tissues was recently reported to play an important role in repairing the ischemic heart (Lai RC, et al., Stem Cell Res 2010, 4:214–222). Clearly, stem cell exosomes contain many factors, including proteins and microRNAs that can contribute to improving the pathology of damaged tissues.

The significance of the results of Zhou and colleagues and others is that stem cells may not need to be used clinically to treat diseased or injured tissue directly. Instead, exosomes released from the stem cells, which can be rapidly isolated by centrifugation, could be administered easily without the safety concerns of aberrant stem cell differentiation, transformation, or recognition by the immune system. Also, given that human umbilical cord exosomes are therapeutic in a rat model of acute kidney injury, it is likely that stem cell exosomes from a donor (allogeneic exosomes) would be effective in clinical studies without side effects.

These are fabulously interesting results, but Zhou and colleagues have also succeeded in raising several important questions. For example: What are the key pathways targeted by stem cell exosomes to regenerate injured renal and cardiac tissue? Are other tissues as susceptible to the therapeutic effects of stem cell exosomes? Do all stem cells release similar therapeutic vesicles, or do certain stem cells release vesicles targeting only specific tissue and regulate tissue-specific pathways? How can the therapeutic activity of stem cell exosomes be increased? What is the best source of therapeutic stem cell exosomes?

Despite these important remaining questions, the demonstration that hucMSCderived exosomes block oxidative stress, prevent cell death, and increase cell proliferation in the kidney makes stem cell-derived exosomes an attractive therapeutic alternative to stem cell transplantation.

See Dorronsoro and Robbins: Regenerating the injured kidney with human umbilical cord mesenchymal stem cell-derived exosomes. Stem Cell Research & Therapy 2013 4:39.