ORLANDO – A second hematopoietic stem cell transplant can be a successful salvage therapy for a child who has experienced a relapse following a first allogeneic transplant, investigators report.
A retrospective study of 221 children who experienced a relapse after a first hematopoietic stem cell transplant (HSCT) showed that 3-year overall survival (OS) was six times higher among those who had second HSCT, compared with those who did not, reported Akshay Sharma, MBBS, from St. Jude’s Children’s Research Hospital in Memphis.
“We found that factors that are typically associated with poor outcomes after transplant such as disease status at the time of first transplantation – being in remission or not, type of transplant – myeloablative or reduced intensity, and choice of donor were generally not significantly predictive of outcomes following posttransplant relapse in our multivariable model,” he said at the Transplantation and Cellular Therapy Meetings.
Relapse is the most common cause of death after HSCT, and 20%-30% of children who undergo allogeneic HSCT will experience a relapse.
To study this issue, Dr. Sharma and colleagues took a retrospective look at 703 patients 21 and younger who received a first alloHSCT at St. Jude’s for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) or myelodysplastic syndrome from 1990 through 2018. Of this cohort, 211 patients (31%) experienced a relapse after transplant.
There were no significant differences between patients who had a relapse and those who did not in sex, race, conditioning-regimen intensity, performance status, donor type, or graft type (peripheral blood stem cell, umbilical cord blood, bone marrow), or in the incidence of acute graft-versus-host disease GVHD.
The investigators found that, as expected, outcomes were poor for patients who experienced a posttransplant relapse, with 3-year overall survival from relapse for the 221 patients of just 10%.
In multivariable analysis controlling for sex, disease status at the time of first transplant, interval from first transplant to relapse, management after relapse, chronic GVHD and year of relapse, factors significantly associated with worse overall survival were relapse within 6 months of transplant vs. later than 6 months (hazard ratio, 4.6; P < .001) and decade of transplant (HR, 2.6 for 1990-2000 and 1.6 for 2001-2010 vs. 2011-2018; P < .001).
In contrast, both second HSCT and donor lymphocyte infusion were associated with better overall survival, compared with postrelapse chemotherapy or supportive care (HR, 0.04 and 0.6, respectively; P < .001 for both comparisons).
A longer interval from first transplant to relapse was the strongest predictor of long-term survival, Dr. Sharma said at the meeting held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research.
Among the 221 patients who had a relapse, 61 (28%) had a second HSCT, 28 (13%) received only donor lymphocyte infusions, without second transplant, and 132 (62%) received either chemotherapy or supportive care.
The 3-year overall survival rate for patients who received a second transplant was 28%, compared with 4% for those who did not have a repeat HSCT. The most important independent predictors for getting a second transplant were longer time to relapse after first transplant, first transplantation from a matched sibling donor instead of from a haploidentical donor, some degree of acute GVHD, and decade of first transplant (current decade vs. earlier decades).
The investigators also looked at guideline recommendations from both the American Society of Hematology and UK National Health Service regarding second allogenenic transplant after relapse.
ASH guidelines say that “patients with chemo-sensitive disease in remission who had a long initial remission (> 6-12 months) after first transplant and who never developed any GVHD” are most likely to benefit from a second transplant.
NHS guidelines say that a second transplant can be considered for patients who experience relapse more than 12 months after first alloHSCT. But as Dr. Sharma and colleagues discovered, patients who had a second transplant had better overall survival regardless of time from first to second transplant, compared with patients who had later relapses but no second transplant.
“With these data in mind, we submit that these ASH and NHS guidelines, which are based on older data from the 1900s and 2000 and are mostly based on adult data and do not include much pediatric data should be reconsidered, at least in the context of pediatric patients as we approach them,” he said.
Jaap-Jan Boelens, MD, PhD, a pediatric transplant specialist at Memorial Sloan Kettering Cancer Center in New York City, who was not involved in the study, said that the use of second transplant as salvage therapy is becoming more common at his center.
“But there is a little nuance,” he said in an interview. “If someone relapses a month after transplant, let’s say, it doesn’t make sense to go for another allo transplant. But if the interval between transplant is longer, more than half a year, we usually consider going for a second allo transplant.”
The decision to attempt a second transplant may also hinge on the disease the patient is being treated for, and on the depth of remission prior to relapse, he said.
Reggie E. Duerst, MD, director of the Stem Cell Transplant Program at Ann & Robert H. Lurie Children’s Hospital of Chicago, said that trying to replicate the conditions of the first transplant may not work.
“It’s also a function of who was the donor for the first transplant – was it a matched sibling? And then for the second one do you go to an unrelated donor, or a half-matched relative, banking on the fact that the donor’s immune system for the second transplant is going to be able to mediate some kind of graft-versus-leukemia effect that wasn’t there the first time around?” he said.
Dr. Duerst, who was not involved in the study, noted that, for some patients with lymphoid malignancies, chimeric antigen receptor (CAR) T-cell therapy may be a more effective salvage strategy than second transplant, but added that it’s still too soon to know which strategy will be more effective.
The study was supported by St. Jude’s, the American Society of Hematology, and the American Society for Transplantation and Cellular Therapy. Dr. Sharma, Dr. Boelens, and Dr. Duerst reported having no relevant disclosures.
SOURCE: Sharma A et al. TCT 2020,