Hypomethylating Agents in Children With Relapsed/Refractory AML

Hypomethylating agents are generally considered to be agents of choice for older adults with acute myeloid leukemia who cannot tolerate the rigors of more intensive therapies, but HMAs also can serve as a bridge to transplant for children and young adults with relapsed or refractory acute myeloid leukemia.

That’s according to Himalee S. Sabnis, MD, MSc and colleagues at Emory University and the Aflac Cancer and Blood Disorders Center at Children’s Healthcare of Atlanta.

In a scientific poster presented during the annual meeting of the American Society of Pediatric Hematology/Oncology, the investigators reported results of a retrospective study of HMA use in patients with relapsed or refractory pediatric AML treated in their center.

Curative Intent and Palliation

They identified 25 patients (15 boys) with a median age of 8.3 years (range 1.4 to 21 years) with relapsed/refractory AML who received HMAs for curative intent prior to hematopoietic stem cell transplant (HSCT), palliation, or in combination with donor leukocyte infusion (DLI).

Of the 21 patients with relapsed disease, 16 were in first relapse and 5 were in second relapse or greater. Four of the patients had primary refractory disease. The cytogenetic and molecular features were KMT2A rearrangements in six patients, monosomy 7/deletion 7 q in four patients, 8;21 translocation in three patients, and FLT3-ITD mutations in four patients.

The patients received a median of 5.3 HMA cycles each. Of the 133 total HMA cycles, 87 were with azacitidine, and 46 were with decitabine.

HMAs were used as monotherapy in 62% of cycles, and in combination with other therapies in 38%. Of the combinations, 16 were with donor leukocyte infusion, and 9 were gemtuzumab ozogamicin (Mylotarg).

Of the 13 patients for whom HMAs were used as part of treatment plan with curative intent, 5 proceeded to HSCT, and 8 did not. Of the 5 patients, 1 died from transplant-related causes, and 4 were alive post transplant. Of the 8 patients who did not undergo transplant, 1 had chimeric antigen receptor T- cell (CAR T) therapy, and 7 experienced disease progression.

The mean duration of palliative care was 144 days, with patients receiving from one to nine cycles with an HMA, and no treatment interruptions due to toxicity.

Of 5 patients who received donor leukocyte infusions, 3 reached minimal residual disease negativity; all 3 of these patients had late relapses but remained long-term survivors, the investigators reported.

They concluded that “hypomethylating agents can be used effectively as a bridge to transplantation in relapsed and refractory AML with gemtuzumab ozogamicin being the most common agent for combination therapy. Palliation with HMAs is associated with low toxicity and high tolerability in relapsed/refractory AML. Use of HMAs with DLI can induce sustained remissions in some patients.”

The authors propose prospective clinical trials using HMAs in the relapsed/refractory pediatric AML setting in combination with gemtuzumab ozogamicin, alternative targeted agents, and chemotherapy.

HMAs in Treatment-Related AML

Shilpa Shahani, MD, a pediatric oncologist and assistant clinical professor of pediatrics at City of Hope in Duarte, Calif., who was not involved in the study, has experience administering HMAs primarily in the adolescent and young adult population with AML.

“Azacitidine and decitabine are good for treatment-related leukemias,” she said in an interview. “They can be used otherwise for people who have relapsed disease and are trying to navigate other options.”

Although they are not standard first-line agents in younger patients, HMAs can play a useful role in therapy for relapsed or refractory disease, she said.

The authors and Shahani reported having no conflicts of interest to disclose.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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