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Kirsten-M.-Williams

Helpful, hopeful news for bone marrow transplant patients

Kirsten-M.-Williams

Research published online Dec. 13, 2017, by The Lancet Haematology and co-led by Kirsten M. Williams, M.D., suggests that a new imaging agent can safely show engraftment as early as days after transplant – giving a helpful and hopeful preview to patients and their doctors.

Leukemia can be a terrifying diagnosis for the more than 60,000 U.S. patients who are told they have this blood cancer every year. But the treatment for this disease can be just as frightening. For patients with certain forms of leukemia, the only chance they have for a cure is to receive a massive dose of radiation and chemotherapy that kills their hematopoietic stem cells (HSCs), the cells responsible for making new blood, and then receive new HSCs from a healthy donor.

While patients are waiting for these new cells to go to the bone marrow factory and begin churning out new blood cells, patients are left without an immune system. Devoid of working HSCs for two to four weeks – or longer, if a first transplant doesn’t take – patients are vulnerable to infections that can be just as deadly as their original cancer diagnosis.

As they wait in the protected confines of a hospital, patients who undergo HSC transplants receive blood tests every day to gauge successful engraftment, searching for the presence of immune cells called neutrophils, explains Kirsten M. Williams, M.D., blood and bone marrow transplant specialist at Children’s National Health System.

“As you head into week three post-transplant and a patient’s cell counts remain at zero, everyone starts to get nervous,” Dr. Williams says. The longer a patient goes without an immune system, the higher the chance that they’ll develop a life-threatening infection. Until recently, Dr. Williams says, there has been no way beyond those daily blood tests to assess whether the newly infused cells have survived and started to grow early healthy cells in the bone marrow, a process called engraftment.

A new study could change that paradigm. Research published online Dec. 13, 2017, by The Lancet Haematology and co-led by Dr. Williams suggests that a new imaging agent can safely show engraftment as early as days after transplant – giving a helpful and hopeful preview to patients and their doctors.

The study evaluated an investigational imaging test called 18F-fluorothymidine (18F-FLT). It’s a radio-labeled analogue of thymidine, a natural component of DNA. Studies have shown that this compound is incorporated into just three white blood cell types, including HSCs. Because it’s radioactive, it can be seen on various types of common clinical imaging exams, such as positron emission tomography (PET) and computed tomography (CT) scans. Thus, after infusion, the newly infused developing immune system and marrow is readily visible.

To see whether this compound can readily and safely visualize transplanted HSCs, Dr. Williams and colleagues tested it on 23 patients with various forms of high-risk leukemia.

After these patients received total-body irradiation to destroy their own HSCs, they received donor HSCs from relatives or strangers. One day before they were infused with these donor cells, and then at five or nine days, 28 days, and one year after transplantation, the patients underwent imaging with the novel PET/and CT scan imaging platform.

Each of these patients had successful engraftment, reflected in blood tests two to four weeks after their HSC transplants. However, the results of the imaging exams revealed a far more complicated and robust story.

With 18F-FLT clearly visible in the scans, the researchers saw that the cells took a complex journey as they engrafted. First, they migrated to the patients’ livers and spleens. Next, they went to the thoracic spine, the axial spine, the sternum, and the arms and legs. By one year, most of the new HSCs were concentrated in the bones that make up the trunk of the body, including the hip, where most biopsies to assess marrow function take place.

Interestingly, notes Dr. Williams, this pathway is the same one that HSCs take in the fetus when they first form. Although experimental model research had previously suggested that transplanted HSCs travel the same route, little was known about whether HSCs in human patients followed suit.

The study also demonstrated that the radiation in 18F-FLT did not adversely affect engraftment. Additionally, images could identify success of their engraftments potentially weeks faster than they would have through traditional blood tests – a definite advantage to this technique.

“Through the images we took, these patients could see the new cells growing in their bodies,” Dr. Williams says. “They loved that.”

Besides providing an early heads up about engraftment status, she adds, this technique also could help patients avoid painful bone marrow biopsies to make sure donor cells have taken residence in the bones or at the very least help target those biopsies. It also could be helpful for taking stock of HSCs in other conditions, such as aplastic anemia, in which the body’s own HSCs fade away. And importantly, if the new healthy cells don’t grow, this test could signal this failure to doctors, enabling rapid mobilization of new cells to avert life-threatening infections and help us save lives after transplants at high risk of graft failure.

“What happens with HSCs always has been a mystery,” Dr. Williams says. “Now we can start to open that black box.”

Dr. Williams’ co-authors include co-lead author Jennifer Holter-Chakrabarty, M.D., Quyen Duong, M.S., Sara K. Vesely, Ph.D., Chuong T. Nguyen, Ph.D., Joseph P. Havlicek, Ph.D., George Selby, M.D., Shibo Li, M.D., and Teresa Scordino, M.D., University of Oklahoma; Liza Lindenberg, M.D., Karen Kurdziel, M.D., Frank I. Lin, M.D., Daniele N. Avila, N.P., Christopher G. Kanakry, M.D., Stephen Adler, Ph.D., Peter Choyke, M.D., and senior author Ronald E. Gress, M.D., National Cancer Institute; Juan Gea-Banacloche, M.D., Mayo Clinic Arizona; and Catherine “Cath” M. Bollard, M.D., MB.Ch.B., Children’s National.

Research reported in this story was supported by the National Institutes of Health, Ben’s Run/Ben’s Gift, Albert and Elizabeth Tucker Foundation, Mex Frates Leukemia Fund, Jones Family fund and Oklahoma Center for Adult Stem Cell Research.

cord blood

T-cell therapy success for relapsing blood cancer

cord blood

A unique immunotherapeutic approach that expands the pool of donor-derived lymphocytes (T-cells) that react and target three key tumor-associated antigens (TAA) is demonstrating success at reducing or eliminating acute leukemias and lymphomas when these cancers have relapsed following hematopoietic stem cell transplant (HSCT).

“There’s currently a less than 10 percent chance of survival for a child who relapses leukemia or lymphoma after a bone marrow transplant—in part because these patients are in a fragile medical condition and can’t tolerate additional intense therapy,” says Kirsten Williams, M.D., a blood and marrow transplant specialist in the Division of Hematology at Children’s National Health System, and principal investigator of the Research of Expanded multi-antigen Specifically Oriented Lymphocytes for the treatment of VEry High Risk Hematopoietic Malignancies (RESOLVE) clinical trial.

The unique manufactured donor-derived lymphocytes used in this multi-institutional Phase 1 dose-ranging study are receptive to multiple tumor-associated antigens within the cell, including WT1, PRAME, and Survivin, which have been found to be over-expressed in myelodysplastic syndromes (MDS), acute myeloid leukemia (AML), B-cell AML/MDS, B-cell acute lymphoblastic leukemia (ALL), and Hodgkins lymphoma. Modifying the lymphocytes for several antigens, rather than a single target, broadens the ability of the T-cells to accurately target and eradicate cancerous cells.

Preliminary results demonstrate a 78 percent response rate to treatment, and a 44 percent rate of total remission for participating patients. To date, nine evaluable patients with refractory and relapsed AML/MDS, B-cell ALL, or Hodgkins lymphoma have received 1-3 infusions of the expanded T-cells, and of those, seven have responded to the treatment, showing reduction in cancer cells after infusion with little or no toxicity. All of these patients had relapse of their cancer after hematopoietic cell transplantation. The study continues to recruit eligible patients, with the goal of publishing the full study results within the next 12 months.

“Our preliminary data also shows that this new approach has few if any side effects for the patient, in part because the infused T-cells target antigens that are found only in cancer cells and not found in healthy tissues,” Dr. Williams notes.

The approach used to expand existing donor-derived TAA-lymphocytes, rather than using unselected T cells or genetically modified T-cells as in other trials, also seems to reduce the incidence of post infusion graft versus host disease and other severe inflammatory side effects. Those side effects typically occur when the infused lymphocytes recognize healthy tissues as foreign and reject them or when the immune system reacts to the modified elements of the lymphocytes, she adds.

“These results are exciting because they may present a truly viable option for the 30 to 40 percent of children who will relapse post-transplant,” Dr. Williams concludes. “Many of the patients who participated were given two options: palliative care or this trial. To see significant success and fewer side effects gives us, and families with children facing relapsing leukemia, some hope for this new treatment.”

Dr. Williams discussed the early outcomes of the RESOLVE trial during an oral presentation at the American Society for Blood and Marrow Transplantation meeting on February 22, 2017.

“The early indicators are very promising for this patient population,” says Catherine Bollard, M.D., M.B.Ch.B., Chief of the Division of Allergy and Immunology, Director of the Program for Cell Enhancement and Technologies for Immunotherapy (CETI) at Children’s National, and senior author of the study. “If we can achieve this, and continue to see good responses with few side effects, it’s possible these methods could become a viable alternative to HSCT for patients with no donor match or who aren’t likely to tolerate transplant.”

This is one of the first immunotherapeutic approaches to successfully capitalize on the natural ability of human T-cells to kill cancer, though previous research has shown significant success for this approach in reducing the deadly impact of several viruses, including Epstein-Barr virus, adenovirus, and cytomegalovirus, post HSCT. These new findings have led to the development of additional clinical trials to investigate applications of this method of TAA-lymphocyte manufacture and infusion for pre-HSCT MDS/AML, B-cell ALL, Hodgkins Lymphoma, and even some solid tumors.