City of Hope doctors participated in research presented at the American Society of Hematology (ASH) virtual meeting, held Dec. 5 to 8, that is helping advance the treatment of blood cancers, including one study that demonstrated allogeneic stem cell transplants do have a survival benefit for older adults with myelodysplastic syndromes (MDS) compared with the current standard of care.
The study is the largest and most definitive trial to demonstrate the benefits of an allogeneic stem cell transplantation for older adults with MDS, and is just one of numerous studies that City of Hope doctors are helping to lead with the aim of finding more effective treatments for various blood cancers.
“This year’s ASH conference truly showcases City of Hope’s leadership in finding more effective treatments for blood cancers,” said Stephen J. Forman, M.D., director of City of Hope’s Hematologic Malignancies Research Institute. “Whether it’s finding innovative treatments to make it possible for more older adults with cancer to receive stem cell transplants, or pursuing therapies that are more effective with fewer side effects, City of Hope doctors continue to lead innovative research in blood cancers and other hematological malignancies.”
City of Hope doctors are leading novel clinical trials for patients with leukemia, lymphoma and other blood cancers.
Stem cell transplants for older adults
Allogeneic hematopoietic cell transplantation, or stem cell/bone marrow transplants, for blood cancers that have recurred or are difficult to treat can put the disease into long-term remission and provide a potential cure. The therapy establishes a new, disease-free blood and immune system by transplanting healthy blood stem cells from a donor into a cancer patient after destroying the patient’s unhealthy bone marrow.
City of Hope and other institutions started this therapy in 1976, primarily for younger patients with blood cancers. The therapy involves using high-dose chemotherapy and/or radiotherapy to make room for a person to receive new stem cells; serious side effects can also occur after transplant. Because of these and other considerations, for many years, older adults with blood cancers have not been considered for transplants.
City of Hope has been leading the way to make transplants possible for more older adults with various cancers.
A new study presented at ASH demonstrates that transplants are now a possibility and beneficial for patients with myelodysplastic syndromes (MDS). Approximately 13,000 people in the United States each year are diagnosed with MDS, an umbrella term describing several blood disorders that begin in the bone marrow.
Co-led by City of Hope’s Ryotaro Nakamura, M.D., director of City of Hope’s Center for Stem Cell Transplantation, the study is the largest and first trial to demonstrate the benefits of an allogeneic stem cell transplantation for older adults with MDS as opposed to the standard of care currently provided to these patients. The multicenter trial for patients aged 50 to 75 with serious MDS compared how long transplant patients survived with those who didn’t receive a transplant, as well as disease progression and quality of life. The transplant therapy used reduced-intensity conditioning, which delivers less chemotherapy and radiation before transplant and relies more on the anti-tumor effects of the therapy.
Between 2014 and 2018, the study enrolled 384 participants at 34 cancer centers nationwide. It included 260 patients who were able to find a donor for a transplant, as well as 124 patients who did not find a donor for a transplant.
After three years, nearly 48% of MDS patients who found a donor for transplant had survived compared with about 27% of those patients who didn’t have a donor for transplant and received current hypomethylating therapy, a type of chemotherapy that is current standard of care for MDS. Leukemia-free survival — which is relevant because myelodysplastic syndrome can develop into leukemia — was also greater in transplant recipients after three years — nearly 36% — compared with about 21% for those who did not have a transplant.
“There was a large and significant improvement in survival for patients who had a transplant,” Nakamura said. “The benefit margin in overall survival was over 20% [21.3%] for patients who had a transplant.”
In addition, quality of life was the same for both transplant and nontransplant patients. There were no clinically significant differences when taking such measurements as physical and mental competency scores.
“This is an extremely exciting study because it provides evidence that stem cell transplant is highly beneficial for older patients with serious MDS. It will likely be practice-changing for this group,” Nakamura said. “Before, many doctors wouldn’t even consider a transplant for this group of patients, but our study demonstrates that these patients should be evaluated for a transplant, which could potentially provide a cure for their disease.”
The trial is part of Blood and Marrow Transplant Clinical Trials Network, which was established with support from the National Heart, Lung, and Blood Institute and National Cancer Institute because of a critical need for multi-institutional clinical trials focused directly on improving survival for patients undergoing hematopoietic cell transplantation.
CAR T for chronic lymphocytic leukemia
Patients with relapsed or difficult-to-treat chronic lymphocytic leukemia/small lymphocytic leukemia continue to do well 24 months after receiving lisocabtagene maraleucel (liso-cel) chimeric antigen receptor (CAR) T cells, according to Tanya Siddiqi, M.D., director of City of Hope’s Chronic Lymphocytic Leukemia (CLL) Program, which is part of the Toni Stephenson Lymphoma Center.
Overall, 23 and 22 patients were evaluated for safety and efficacy in this phase 1 trial, respectively. Their median age was 66 and they had received a median of four prior therapies; all patients had received prior ibrutinib, which is one of the standard-of-care drugs for CLL.
The overall response rate, or patients whose CLL diminished after liso-cel CAR T cell therapy, was 82%; 45% of patients also had complete responses, or remissions.
After 15 months of treatment, 53% of patients maintained their responses to the therapy, and six patients continued to be in remission. After 18 months, 50% of patients maintained their response, and there were five remissions. All seven patients who completed the 24-month study maintained their response. Median progression-free survival, or the amount of time the cancer did not worsen during and after treatment, was 18 months.
As early as 30 days after receiving liso-cel, about 75% of 20 patients evaluated for the therapy’s efficacy had undetectable minimal residual disease (MRD, or no detectable traces of cancer) in the blood and 65% had undetectable MRD in the marrow.
“These are remarkable results for a group of patients that prior to this CAR T treatment had no good treatment options if they had already progressed on novel targeted therapies like ibrutinib and venetoclax,” Siddiqi said. “Liso-cel is providing new hope for CLL patients, and the remissions are also long lasting with few serious side effects.”
Because of its safety and effectiveness in clinical trials, liso-cel, which targets the CD19 protein on cancer cells, may soon receive approval from the Food and Drug Administration as a commercial therapy for relapsed or refractory B cell lymphoma. City of Hope is also taking part in the phase 2 trial of liso-cel in CLL patients.
Antibody treatment for Hodgkin lymphoma
Patients who have Hodgkin lymphoma that has not been cured by initial treatment will usually receive more chemotherapy and an autologous hematopoietic cell transplant. But even after a stem cell transplant, recurrence of the lymphoma is possible.
This multicenter phase 2 clinical trial, led by City of Hope, examined whether treating patients with brentuximab vedotin (BV), an antibody-based treatment that targets delivery of chemotherapy only to Hodgkin lymphoma cells, and nivolumab, which works by blocking the PD-1 immune checkpoint pathway that Hodgkin lymphoma hijacks to evade the immune system, was safe and effective as consolidation to prevent disease recurrence after transplant in patients with high-risk Hodgkin lymphoma.
Alex Herrera, M.D., assistant professor in City of Hope's Department of Hematology & Hematopoietic Cell Transplantation, discussed 19-month progression-free survival for trial participants, as well as overall survival, safety and response rates during ASH.
Fifty-nine patients were enrolled in the trial. Patients received the consolidation treatment starting a median of 54 days after transplant, and received a median of eight cycles of the therapy.
The 19-month progression-free survival in patients was 92%, and overall survival in patients was 98%. Only three patients relapsed after receiving BV and nivolumab consolidation after transplant, and one patient passed away due to pneumonia unrelated to the study treatment.
The most common sides effects related to the treatment were peripheral neuropathy (51%), neutropenia (42%), fatigue (37%) and diarrhea (29%).
“Using brentuximab vedotin and nivolumab after transplant is a promising approach for preventing relapse of Hodgkin lymphoma after transplant that merits further study,” Herrera said.
Innovative approaches for GVHD
Historically, a bone marrow/stem cell transplant is more likely to be effective if patients have a donor who is a 100% match, or as close to that as possible. Finding that perfect match is more difficult for African Americans, Latinos, Asian Americans and other ethnic groups, as bone marrow donor registries are still trying to increase the number of non-white donors.
Transplant doctors are also looking for ways to make the transplant more effective if a perfect match can’t be found; donors who are not a 100% or close match are referred to as mismatched unrelated. One major barrier to these transplants being effective is a condition known as graft-versus-host-disease (GVHD). The condition, which is more common in transplants involving mismatched donors, is caused by donated cells that recognize the recipient's cells as foreign and attack them, damaging the skin, eyes, lungs, liver and digestive tract.
In order to help prevent GVHD, therapies can be given to patients after transplant. A prospective clinical trial at City of Hope examined whether using cyclophosphamide after an infusion of stem cells could prevent GVHD.
Thirty-eight patients were enrolled in the trial, which is the first to examine the use of cyclophosphamide in transplants with a mismatched unrelated donor.
With a median follow-up period of 18 months, 87% of patients had survived, and the majority did not relapse or develop severe GVHD.
During the first 100 days post-transplant, acute GVHD incidence was around 50%; most cases were mild to moderate, while severe GVHD was only 15%. A year after transplant, 52% of patients had some form of chronic GVHD, but only 3% had moderate or severe chronic GVHD.
The trial also examined toxicities, infections and immune system recovery after the transplant.
“Our study showed that patients who received a transplant from a mismatched unrelated donor using post-transplant cyclophosphamide had a comparable outcome to what we see in matched donor transplants with few cases of serious GVHD cases,” said Monzr Al Malki, M.D., associate clinical professor in City of Hope’s Department of Hematology & Hematopoietic Cell Transplantation and director of unrelated donor BMT and haploidentical transplant programs. “Our data support further development of this therapy in transplant patients who would otherwise have no suitable donors and limited treatment options.”
City of Hope’s Anthony Stein, M.D., also led a pilot trial that examined whether a new treatment approach may reduce the rate of GVHD in patients with acute myelogenous leukemia (AML) who have received an allogeneic hematopoietic cell transplant. Although a transplant can put AML into remission, GVHD remains the main serious complication after transplant, impacting a patient’s quality of life and increasing health care costs.
Eighteen patients between the ages of 18 and 60 enrolled in the trial. Each patient received a novel conditioning regimen of total marrow and lymphoid irradiation, which targets a patient’s marrow and lymph nodes while reducing radiation to other parts of the body, and cyclophosphamide, a therapy that suppresses the immune system. Tacrolimus was also provided to patients.
Radiation was delivered twice daily on the fourth day before transplant and on the day of transplant without chemotherapy. Cyclophosphamide was given to patients on the third and fourth day after transplant.
There were mild to moderate toxicities. Acute GVHD developed in two patients, and only one patient developed the most serious GVHD. Five patients developed mild chronic GVHD. Nearly 60% of patients had not developed GVHD or the condition had not worsened after a year.
After a year, all patients had survived, and 83% had not relapsed. After two years, nearly 86% of patients had survived, and the relapse number remained the same.
The therapeutic approach did not interfere with the transplant process as all patients engrafted, or the donor’s cells started to produce bone marrow and immune cells.
“This is welcome news for AML patients who receive an allogeneic transplant and are concerned about developing GVHD,” said Stein, associate director of City of Hope's Gehr Family Center for Leukemia Research. “Our study demonstrated that using this new combination of therapies is safe and feasible and does not interfere with the engraftment process.”
“In addition, after a year, patients in this trial were no longer taking immunosuppressive therapy and had an improved quality of life,” Stein said. He added that because many of the patients didn’t have GVHD, health care costs after a year were also lower than if patients required treatment for the condition.
City of Hope now plans to start a larger phase 2 trial using this treatment approach.
Bispecific antibodies show promise
Mosunetuzumab is a promising new immunotherapy for the treatment of relapsed/refractory non-Hodgkin lymphoma (NHL) that recently received breakthrough therapy designation from the Food and Drug Administration. The designation is intended to expedite the development and review of drugs for serious or life-threatening diseases.
Elizabeth Budde, M.D., Ph.D., assistant professor in City of Hope's Department of Hematology & Hematopoietic Cell Transplantation, is leading clinical trials that are showing how well mosunetuzumab works against NHL. At this year’s ASH, one trial discussed is how the therapy is working for patients with follicular lymphoma.
Mosunetuzumab is a bispecific antibody targeting both CD3 (a protein found on the surface on T cells) and CD20 on the surface of B cells. The therapy redirects T cells to engage and eliminate malignant B cells.
Sixty-two patients, ranging in age from 27 to 85 years old, were enrolled in the trial for follicular lymphoma. They received intravenous doses of mosunetuzumab.
Sixty-eight percent of the patients responded to the therapy, and 50% had a complete response, or went into remission. Consistent complete response rates occurred even in patients with double refractory disease and patients who received prior CAR T cell therapy. Median duration of response was approximately 20 months, and media progression-free survival was nearly one year.
Side effects were reported in 60 patients with serious adverse effects in 22 patients. The most frequently reported serious side effects were hypophosphatemia, an electrolyte disorder, and neutropenia, a condition caused by low numbers of white blood cells. Fourteen patients experienced cytokine release syndrome, but none required extensive treatment for it.
Neurological side effects included headache, insomnia and dizziness.
“Patients in this trial had high response rates and their disease remained in control for a year,” Budde said. “This is remarkable because many patients were no longer responding to other therapies.”