Next-Generation Cell Therapy for Graft-Versus-Host Disease


Endonovo Therapeutics, Inc has announced its development of a cell-based treatment for Graft-versus-Host Disease (GvHD). This treatment utilizes umbilical cord blood stem cells that have been grown and enhanced by specific treatments.

GVHD occurs when newly transplanted donor cells attack the recipient’s body. It can occur after a bone marrow or stem cell transplant if the cells have not been properly matched or even if the donor and recipient are relatively well matched. The chances of suffering GVHD are around 30 – 40% if the donor and recipient are genetically related and close to 60 – 80% when the donor and recipient are not related.

GVHD can be either acute or chronic and the symptoms of GvHD can be either mild or severe. Typically, acute GVHD comes on within the first 6 months after a transplant. Common acute symptoms include: Abdominal pain or cramps, nausea, vomiting, and diarrhea, Jaundice (yellow coloring of the skin or eyes) or other liver problems, skin rash, itching, redness on areas of the skin. Chronic GVHD usually starts more than 3 months after a transplant, and can last for the lifetime or the patient. The symptoms of chronic GvHD include: dry eyes or vision changes, dry mouth, white patches inside the mouth, and sensitivity to spicy foods, fatigue, muscle weakness, and chronic pain, joint pain or stiffness, skin rash with raised, discolored areas, as well as skin tightening or thickening, shortness of breath, weight loss.

Endonovo uses a novel method to enhance stem cells. Their so-called “Cytotronics platform” utilizes Time-Varying Electromagnetic Field (TVEMF) technology to expand and enhance the therapeutic properties of stem cells and other types of cells for regenerative treatments and tissue engineering. This platform can potentially optimize cell-based therapies so that they have greater therapeutic potential than they had prior to their treatment.

The Cytotronics™ platform dates back to experiments conducted at NASA to expand stem cells in culture. NASA’s goal was to create stem cell therapies that could be used to treat astronauts during long-term space exploration. NASA scientists showed that Time-Varying Electromagnetic Fields (TVEMF) could stimulate the expansion of stem cells in the lab. Additionally, TVEMF increased the expression of dozens of genes related to cell growth, tumor suppression, cell adhesion and extracellular matrix production.

By testing and tweaking this technology over a period of 15 years, Endonovo scientists created a novel protocol for augmenting the therapeutic properties of cells in culture through physics rather than genetic engineering. The Cytotronics™ platform seems to be able to make stem cells that express higher levels of key genes necessary for tissue healing and regeneration.

As an example of the efficacy of this technology. Endonovo scientists have shown that Cytotronic™ expansion of peripheral blood stem cells resulted in an over 80-fold expansion of CD34+ cells in as little as 6 days.

Endonovo is using the Cytotronic platform to enhance the regenerative properties of mesenchymal stem cells (MSCs), which have the capacity to staunch inflammation in patients with GvHD and other inflammatory diseases.

However, despite their promise, MSC-based therapies suffer from poor engraftment and short-term survival when transplanted into sick patients. These remain major limitations to the effective therapeutic use of MSCs. If there was a safe and effective way to beef up the survival and regenerative properties of MSCs, such a technique would be indispensable.  This makes MSCs prime candidates for the Cytotronic Platform.

Dr. Donnie Rudd, Chief Scientist & Director of Intellectual Property at Endonovo, said: “Our Cytotronics platform is particularly suited to address many of the issues that have plagued stem cell therapies that have recently failed, such as their loss of potency and self-renewal when expanded ex vivo, their poor engraftment and their limited ability to survive when transplanted.”

Earlier this year, Endonovo announced a protocol for the creation of a cell mixture from a portion of the human umbilical cord co-cultured with adipose-derived stem cells. This resulting cell mixture contains a rich source of highly-proliferative, immunosuppressive cells that are not recognized by the patients immune system, since they contain neither of the major histocompatibility markers (HLA double negative). These cells are “immune privileged,” which means that are not recognized as foreign cells by the patient’s immune system, and therefore are a significant source of cells for MSC-based therapies.

Endonovo Therapeutics has used this new technology to create a biologically potent, off-the-shelf, allogeneic treatment for Graft-Versus-Host disease and a wide-array of other conditions. They would like to test these products in clinical trials eventually.

Endonovo hopes that stem cells enhanced by the Cytotronics™ platform will become a major innovation in the regenerative medicine market.

“We are very excited to be a leader in the development of next-generation, ex vivo enhanced cells for regenerative medicine,” stated Endonovo CEO, Alan Collier. “We have seen several stem cell therapies fail in clinical trials over the last couple of years, which points to a critical need for the development of methods to increase the biological and therapeutic properties of stem cells.”

“We believe that enhancing the biological and therapeutic properties of stem cells using bioelectronics is the future of cell-based therapies,” concluded Mr. Collier.

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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.

Reducing the Incidence of a Deadly Side Effect of Bone Marrow Transplants in Mice


Bone marrow transplants save the lives of leukemia, but they have one risky drawback and that is “graft-versus-host disease.” Graft-versus-host disease (GVHD) results when immune cells in the donor’s bone marrow attack the tissues and cells of the recipient’s body as foreign. Almost half of bone marrow transplant recipients develop graft-versus-host disease (GVHD), the main organs affected are the skin, liver and gut. Obviously, finding a way to quell or even prevent GVHD would be a boon for bone marrow transplantations.

By utilizing a mouse model, researchers at Washington University School of Medicine in St. Louis have managed to reduce the risk of GVHD from bone marrow transplants. Since bone marrow transplants are the only available curative treatment when leukemia returns, decreasing the risk of GVHD is the first step to improving the prognosis of leukemia patients.

The main strategy behind decreasing the effects of GVHD is to direct immune cells from the donor’s bone marrow away from healthy tissue and lead them to their intended purpose, which is to kill cancer cells.

“This is the first example of reducing graft-versus-host disease not by killing the T-cells, but simply by altering how they circulate and traffic,” says John F. DiPersio, MD, PhD, the Virginia E. and Sam J. Golman Professor of Medicine at Barnes-Jewish Hospital and Washington University School of Medicine. “Donor T-cells do good things in terms of eliminating the recipient’s leukemia, but they can also attack normal tissues leading to death in a number of patients. The goal is to minimize graft-versus-host disease, while maintaining the therapeutic graft-versus-leukemia effect.”

By working in a mouse model, Jaebok Choi, PhD, research assistant professor of medicine, showed that if he eliminated or blocked a particular protein known as the interferon gamma receptor on donor T-cells, these cell were unable to migrate to critical organs such as the intestines. However, these same T-cells were still capable of killing leukemia cells.

“The fact that blocking the interferon gamma receptor can redirect donor T-cells away from the gastrointestinal tract, at least in mice, is very exciting because graft-versus-host disease in the gut results in most of the deaths after stem cell transplant,” DiPersio says. “People can tolerate graft-versus-host disease of the skin. But in the GI tract, it causes relentless diarrhea and severe infections due to gut bacteria leaking into the blood, which can result in severe toxicity, reduction in the quality of life or even death in some patients.”

Interferon gamma has, for some time, been known to play a vital role in inflammation. The signal transduction pathway that works downstream of the receptor is just now being better understood. It is this signal transduction pathway downstream of the receptor that is responsible for activating the T-cells so that they cause GVHD. The signaling cascade initiated when interferon gamma binds its receptor activates molecules known as JAK kinases, followed by another protein called “STAT,” and finally a protein called CXCR3. CXCR3 mediates the trafficking of donor T-cells to the GI tract and other target organs.

Deleting the interferon gamma receptor from donor T-cells steers them away from target organs. This, however, leads to a second question: “Could the same result be observed by inhibiting some of the other molecules that act downstream of the interferon gamma receptor?” To address this question, Choi knocked out CXCR3 and discovered that such a knock out reduced graft-versus-host disease, but did not completely wipe it out.

“There are probably additional downstream targets of interferon gamma receptor signaling other than JAKs, STATs and CXCR3 that are responsible for T-cell trafficking to the GI tract and other target organs,” DiPersio says. “We’re trying to figure out what those are.”

This worked beautifully in mice, but could it work in humans? To make these data more relevant to human biology, Choi and DiPersio used drugs known to block JAK kinases in human cells. These drugs are presently approved by the Food and Drug Administration to treat myelofibrosis, which is a pre-leukemic condition in which bone marrow is replaced with fibrous tissue. Ruxolitinib and pacritinib are two such drugs and Choi and DiPersio showed that treating mice with either of these two drugs could mimic the protective effect of deleting the interferon gamma receptor. The JAK inhibitors definitely redirect the donor T-cells away from target organs and reducing graft-versus-host disease in leukemic mice. Unfortunately, they have yet to determine if these drugs preserve the anti-leukemia effect of these T-cells.

“The proof-of-principle behind these experiments is the exciting part,” DiPersio says. “If you can change where the T-cells go as opposed to killing them, you prevent the life-threatening complications and maintain the clinical benefit of the transplant.”

The Cells=Drugs Argument Has Suffered A Significant Blow


The Regenexx blog site has a fascinating article on tow approaches to reducing transplantation rejection. Osiris Corporation has tried to market a stem product that is a kind of one-size-fits-all stem cell approach for regenerative medicine. This takes mesenchymal stem cells from the bone marrow of young patients and concentrated them in a vial for use. Unfortunately, once these stem cells differentiate into other cell types, they are rejected by the patient’s immune system. While using mesenchymal stem cells from a different person can provide regeneration under particular circumstances, the transplants that use a patient’s own stem cells are always the best from the perspective of the immune system.

A study from Northwestern showed that kidney transplant patients who were also given transplants of bone marrow from the kidney donor did not require any immunosuppressive drugs to prevent the immune system from rejecting their new kidney. This shows that instead of stem cells in a vial (a one-size-fits-all approach to regenerative medicine), an individualized approach seems to be far superior. However, the stem cells = drugs dictum of the FDA argues for the stem cells in a vial approach. Unfortunately, in a Phase III clinical trial, Osiris’ Prochymal product spectacularly failed to provide relief to patients suffering from “Graft versus Host Disease (GVHD). Therefore the stem cells in a vial approach failed, but the individualized worked. This shows that the stem cells = drugs ideology is not one that is tied to reality.

To read Regenexx’s fascinating blog post, go here.

Osiris’ Prochymal Mesenchymal Stem Cell Formulation is Safe for Diabetes Treatments


The biotechnology company called Osiris Therapeutics, Inc. has developed an adult mesenchymal stem cell formulation it calls “Prochymal.” Osiris scientists have been busy subjecting Prochymal to a battery of clinical trials that include testing Prochymal as a treatment for chronic obstructive pulmonary disease, Crohn’s disease, myocardial infarction, and acute graft-versus-host disease. Now Osiris is in the process of testing Prochymal as a treatment for newly diagnosed diabetes mellitus.

This clinical trial transferred mesenchymal stem cells from unrelated adult donors into 63 pediatric and adult type diabetics to determine if such a transfer can slow the progression of this debilitating disease. Patients will randomly receive either the stem cells or a placebo. Thus far, no patients who have received the mesenchymal stem cell infusion have shown any adverse reactions, despite receiving the cells from unrelated donors and without any drugs to suppress the immune system. Additionally, no significant differences in insulin levels were observed between the placebo and the experimental group after one year of receiving the mesenchymal stem cell infusion. However, patients who had received Prochymal showed fewer severely low blood glucose concentrations hypoglycemic events) than those who had been given the placebo. The test is still ongoing, and all patients will be observed for another year.

The rationale behind this trial resides in the unique ability of mesenchymal stem cells to down-regulate the immune response. Because type 1 diabetes typically results from the patient’s immune system attacking and destroying the insulin-secreting beta cells found in the pancreatic islets, an influx of mesenchymal stem cells might be able to decelerate the destruction of the beta cells. This suppression of beta cell destruction might lead to the regeneration of the beta cells, since several stem cell populations in the pancreas and pancreatic ducts can differentiate into beta cells. Since, Prochymal is specifically designed to control inflammation, promote tissue regeneration and prevent the formation of scar tissue; it is a prime candidate agent to reduce the loss of beta cells at the onset of type 1 diabetes.

Jay Skyler, professor and medicine and deputy researcher of the Diabetes Research Institute at the University Of Miami Miller School Of Medicine commented, “This groundbreaking study in an important first step in the use of stem cells to potentially alter the course of type 1 diabetes. The ability to safely use stem cells from unrelated donors is an important finding of this study and provides new possibilities for further development and stem cell therapies for type 1 diabetes.”

HIV Drug Maraviroc Reduces Graft-Versus-Host Disease In Stem Cell Transplant Patients


A drug called maraviroc is normally used to treat Human Immunodeficiency Virus (HIV) infections, but work at the University of Pennsylvania suggests that maraviroc redirects the trafficking of immune cells. The significance of these results are profound for transplant patients, since a drug like maraviroc can potentially reduce the incidence of graft-versus-host disease in cancer patients who have received allogeneic (from someone else) stem cell transplantation (ASCT). This research, which was conducted at the Perelman School of Medicine at the University of Pennsylvania, was presented at the 53rd American Society of Hematology Annual Meeting.

Graft-versus-host disease or GvHD occurs as complication after a stem cell or bone marrow transplant. During GvHD, the newly transplanted cells recognize the recipient’s body as foreign and mount an attack against it. Acute cases of GvHD usually occur within the first 3 months after the transplant. Chronic GvHD usually starts more than 3 months after the transplant. GvHD rates vary from 30 – 40% among related bone marrow or stem cells donors and from 60 – 80% between unrelated donors and recipients. The greater the degree of immunological mismatches between the donor and the recipient, the greater the risk of GvHD. After a transplant, the recipient usually takes a battery of drugs that suppress the immune system. These drug treatments help reduce the chances or severity of GvHD.

Standard treatments for GvHD suppress the immune system. Commonly used medicines include methotrexate, cyclosporine, tacrolimus, sirolimus, ATG (Antithymocyte globulin), and alemtuzumab either alone or in combination. High-dose corticosteroids are the most effective treatment for acute GVHD. Antibodies to T cells and other medicines are given to patients who do not respond to steroids. Chronic GvHD treatments include prednisone, (a steroid) with or without cyclosporine. Other treatments include mycophenolate mofetil (CellCept), sirolimus (Rapamycin), and tacrolimus (Prograf). These treatments, if given during the course of the stem cell or bone marrow transplant, reduce but do not eliminate the risk of developing GvHD.

In the current trial, treatment with maraviroc dramatically reduced the incidence of GvHD in organs where it is most dangerous (liver, GI tract, lung, skin — without compromising the immune system and leaving patients more vulnerable to severe infections.

Assistant professor in the division of Hematology-Oncology and a member of the Hematologic Malignancies Research Program at Penn’s Abramson Cancer Center, Ran Reshef, commented: “There hasn’t been a change to the standard of care for GvHD since the late 1980s, so we’re very excited about these results, which exceeded our expectations. Until now, we thought that only extreme suppression of the immune system can get rid of GvHD, but in this approach we are not killing immune cells or suppressing their activity, we are just preventing them from moving into certain sensitive organs that they could harm.”

Reshef and colleagues presented results showing that maraviroc is safe and feasible in stem cell transplant patients who have received stem cells from a healthy donor. A brief course of the drug led to a 73% reduction in severe GvHD in the first six months after transplant, compared with a matched control group treated at Penn during the same time period (6% who received maraviroc developed severe GvHD vs. 22% of other patients receiving standard drug regimens).

Reshef explained, “Just like in real estate, immune responses are all about location, location, location. Cells of the immune system don’t move around the body in a random way. There is a very distinct and well-orchestrated process whereby cells express particular receptors on their surface that allows them to respond to small proteins called chemokines. The chemokines direct the immune cells to specific organs, where they are needed, or in the case of GvHD, to where they cause damage.”

Thirty-eight patients with blood cancers, including acute myeloid leukemia, myelodysplastic syndrome, lymphoma, myelofibrosis, and others, enrolled in the phase I/II trial. All patients received the standard GvHD prevention drugs tacrolimus and methotrexate, plus a 33-day course of maraviroc that began two days before transplant. In the first 100 days after transplant, none of the patients treated with maraviroc developed GvHD in the gut or liver. By contrast, 12.5% of patients in the control group developed GvHD in the gut and 8.3 percent developed it in the liver within 100 days of their transplant.

The differential impact of maraviroc on those organs indicates that the drug is working as expected, by limiting the movement of T lymphocytes to specific organs in the body. Maraviroc works by blocking the CCR5 receptor on the surfaces of lymphocytes. This prevents the lymphocytes from trafficking to certain organs. Maraviroc did not affect GvHD rates in the skin, which might mean that the CCR5 receptor is more important for sending lymphocytes into the liver and the gut than the skin.

After 180 days, the benefit of maraviroc appeared to be partially sustained in patients and the cumulative incidence of gut GvHD rose to 8.8% and the rates of liver GvHD rose only to 2.9%. The cumulative incidence of GvHD in the control group, however, remained higher, at 28.4% for gut and 14.8% for liver GvHD. Based on these data, the research team plans to try a longer treatment regimen with maraviroc to see if longer exposures to maraviroc can its protective effect.

Additionally, maraviroc treatment appeared to neither increase treatment-related toxicities nor alter the relapse rate of their underlying disease. Clearly this drug shows promise for limiting the devastating effects of GvHD in stem transplant patients.