Even the youngest patients with relapsed or refractory B-lineage acute lymphoblastic leukemia (B-ALL) may be able to benefit from chimeric antigen reception T-cell (CAR T) therapy, investigators in an international consortium say.
Among 30 children aged under 2 years at the time of (B-ALL diagnosis, manufacturing of the CAR T product tisagenlecleucel (Kymriah) was feasible in 28 patients, and treatment resulted in high rates of minimal residual disease (MRD) negativity, complete responses, event-free survival, and overall survival, reported Sara Ghorashian, MD from the University College London Great Ormond Street Institute of Child Health, on behalf of the International BFM Resistant Disease Committee.
“The disease-related outcomes noted in this cohort of younger children predominantly with relapsed/refractory infant [mixed lineage leukemia]–rearranged ALL were at least as good as for the ELIANA study,” she said in an oral abstract presented during the European Hematology Association annual congress (Abstract S116).
The international, single-arm, open-label, ELIANA study was a phase 2 trial that included 97 patients aged 3-24 years with relapsed or refractory B-cell ALL, most of whom had previously undergone a hematopoietic stem cell transplant. Of those patients, 79 patients went on to receive a single infusion of the CAR T therapy.
“It’s fantastic data,” said Kevin J. Curran, MD, a pediatric hematologist/oncologist specializing in stem cell transplants and cellular therapy at Memorial Sloan Kettering Cancer Center, New York.
“Pediatric leukemia, while it’s the most common malignancy that happens in children, when you get down to this really small group, this under 3-year-old group, it’s hard to get a cohort, and for them to put together 30 patients, and show these great results is groundbreaking,” he said in an interview.
“Most importantly, it gives hope to parents who have young children who have really difficult to treat leukemia,” he said.
Dr. Curran was not involved in the study.
Scarce data on ALL in infants
“Children under 3 years of age were excluded from the ELIANA study, yet in terms of having often highly aggressive disease, with traditionally poor outcomes with conventional therapy, the need for novel forms of therapy for children with relapsed infant ALL is important,” Dr. Ghorashian said.
Because there is a paucity of data on outcomes in the youngest children, some health authorities will not support the use of tisagenlecleucel in this age group, and there are concerns about difficulties with performing leukapheresis in children weighing less than 10 kg, she noted.
To gain a better understanding of outcomes, members of the International BFM (Berlin-Frankfurt-Munster) Study Group conducted a retrospective analysis of data on all patients assessed for tisagenlecleucel for B-ALL who were aged under 3 years at screening at 1 of 15 centers in Europe and Israel.
A total of 30 patients were screened and had T cells harvested. Of this group, three patients did not receive CAR T infusions, two because of manufacturing failures, and one because of progressive disease.
Of the 27 patients who received CAR T infusions, 26 were evaluable for disease outcomes (1 had yet to reach the 30-day post infusion at the time of data cutoff).
The median age at diagnosis was 4.4 months, and the median age at infusion was 17.4 months; 19 of the 30 children in the entire cohort were boys. Mixed lineage leukemia rearrangements were found in 24 children, and 21 had undergone a stem cell transplant.
The children had a median of two prior lines of therapy, not including transplant. Seven of the children had received inotuzumab (Besponsa) and 11 had received blinotumumab (Blincyto).