.
Two-year disease-free and overall survival measures, as well as the percentage of children who had complete minimal residual disease (MRD) responses, were substantially higher among the 30 infants in the study than in historical controls treated with the same chemotherapy backbone in an earlier trial, Interfant-06.
“These outcome data are very promising, given the poor survival and lack of improvements in outcomes among infants with KMT2A-rearranged ALL in recent decades,” said the investigators, led by Inge M. van der Sluis, MD, PhD, a hematologist-oncologist at Princess Maxima Center for Pediatric Oncology in Utrecht, the Netherlands.
“The low incidence of relapse after treatment with blinatumomab is remarkable, given that in historical controls relapses occur frequently and early during therapy,” the investigators stated. Although the “follow-up time was relatively short” in the study, “it included the period historically defined” as being at high risk of relapse, they said.
The team suggested that future research should assess whether infants benefit from multiple courses of blinatumomab, rather than the one course used in the study, and whether blinatumomab plus chemotherapy can replace stem cell transplants for high-risk infants.
Pediatric community responds
There was excitement on Twitter about the results; a number of pediatric blood cancer specialists were impressed and posted the study on that platform. Comments included, “Wow! After years of stagnation, a huge step forward for infant leukemia” and “great news for infant lymphoblastic leukemia.”
Akshay Sharma, MBBS, a pediatric bone marrow transplant and cellular therapy specialist at St. Jude Children’s Research Hospital, Memphis, also posted. He said in an interview that the findings are “very exciting.”
The “outcomes of children diagnosed with leukemia in their infancy, particularly if they have a KMT2A rearrangement, have been dismal. This is terrific progress and a testament to the role that immunotherapy and novel agents will be playing in treatment of several malignant diseases in the decade to come,” he said.
Another poster, Pratik “Tik” Patel, MD, a pediatric hematology/oncology fellow at Emory University in Atlanta, told this news organization that the study “is welcome news to pediatric oncologists” and highlights “the success in incorporating newer immune-based therapeutics upfront in treatment rather than in relapsed/refractory settings.”
The National Cancer Institute–funded Children’s Oncology Group is thinking the same way. The group is launching a large, randomized trial to test if adding blinatumomab to chemotherapy upfront for B-cell acute lymphoblastic leukemia and lymphoblastic lymphoma improves outcomes in children and young adults aged 1-31 years. Results are due after 2029.
Study details
Blinatumomab is an expensive “T-cell engager” that helps cytotoxic CD3+T cells link to and destroy leukemic CD19+ B cells. Past studies have shown that it’s safe and works in older children and adults with B-lineage ALL after intensive chemotherapy, but until now the approach hadn’t been tested in infants, the investigators said.
The 30 subjects in the study were under a year old and newly diagnosed with KMT2A-rearranged ALL. They were treated with the Interfant-06 chemotherapy regimen – cytosine arabinoside and other agents – plus one postinduction course of blinatumomab at 15 micrograms/m2 per day as a 4-week continuous infusion. Eight of nine high-risk patients had allogeneic hematopoietic stem cell transplants.
Overall survival was 93.3% over a median follow up of 26.3 months, substantially higher than the 65.8% in the Interfant-06 trial. Two-year disease-free survival was 81.6% versus 49.4% in Interfant-06.
Sixteen patients (53%) were MRD negative after blinatumomab infusion and 12 (40%) had low levels of MRD. All of the children who continued chemotherapy went on to become MRD negative.
There were no permanent blinatumomab discontinuations and no treatment related deaths. Serious toxic effects were consistent with those in older patients and included four fevers, four infections, and one case each of hypertension and vomiting.
There were no cases of severe cytokine release syndrome (CRS) because of the low tumor burden of the subjects. Likewise, there were no obvious neurologic adverse events – like CRS, a particular concern with blinatumomab – but “we cannot rule out underreporting of mild neurologic symptoms that may have been unrecognized in infants,” the investigators said.
Patients who relapsed in the study had CNS involvement at relapse. “This underscores the need for adequate intrathecal chemotherapy during the blinatumomab infusion, because the efficacy of blinatumomab for the treatment of CNS leukemia may be limited,” they said.
The work was supported by Amgen, the maker of blinatumomab, as well as the Princess Maxima Center Foundation, the Danish Childhood Cancer Foundation, and others. Dr. Sluis is a consultant and researcher for Amgen. Five other authors were also consultants/advisers/researchers for the company. Dr. Sharma and Dr. Patel didn’t have any relevant disclosures.