Minimal residual disease predicts outcomes in KMT2A-rearranged but not KMT2A-germline infant acute lymphoblastic leukemia: Report from Children's Oncology Group study AALL0631.

We measured minimal residual disease (MRD) by multiparameter flow cytometry at three time points (TP) in 117 infants with KMT2A (lysine [K]-specific methyltransferase 2A)-rearranged and 58 with KMT2A-germline acute lymphoblastic leukemia (ALL) on Children's Oncology Group AALL0631 study. For KMT2A-rearranged patients, 3-year event-free survival (EFS) by MRD-positive (≥0.01%) versus MRD-negative (<0.01%) was: TP1: 25% (±6%) versus 49% (±7%; p = .0009); TP2: 21% (±8%) versus 47% (±7%; p < .0001); and TP3: 22% (±14%) versus 51% (±6%; p = .0178). For KMT2A-germline patients, 3-year EFS was: TP1: 88% (±12%) versus 87% (±5%; p = .73); TP2: 100% versus 88% (±5%; p = .24); and TP3: 100% versus 87% (±5%; p = .53). MRD was a strong independent outcome predictor in KMT2A-rearranged, but not KMT2A-germline infant ALL.

Preclinical efficacy of azacitidine and venetoclax for infant KMT2A-rearranged acute lymphoblastic leukemia reveals a new therapeutic strategy.

Infants with KMT2A-rearranged B-cell acute lymphoblastic leukemia (ALL) have a dismal prognosis. Survival outcomes have remained static in recent decades despite treatment intensification and novel therapies are urgently required. KMT2A-rearranged infant ALL cells are characterized by an abundance of promoter hypermethylation and exhibit high BCL-2 expression, highlighting potential for therapeutic targeting. Here, we show that hypomethylating agents exhibit in vitro additivity when combined with most conventional chemotherapeutic agents. However, in a subset of samples an antagonistic effect was seen between several agents. This was most evident when hypomethylating agents were combined with methotrexate, with upregulation of ATP-binding cassette transporters identified as a potential mechanism. Single agent treatment with azacitidine and decitabine significantly prolonged in vivo survival in KMT2A-rearranged infant ALL xenografts. Treatment of KMT2A-rearranged infant ALL cell lines with azacitidine and decitabine led to differential genome-wide DNA methylation, changes in gene expression and thermal proteome profiling revealed the target protein-binding landscape of these agents. The selective BCL-2 inhibitor, venetoclax, exhibited in vitro additivity in combination with hypomethylating or conventional chemotherapeutic agents. The addition of venetoclax to azacitidine resulted in a significant in vivo survival advantage indicating the therapeutic potential of this combination to improve outcome for infants with KMT2A-rearranged ALL.

Assessment of enrollment characteristics for Children's Oncology Group (COG) upfront therapeutic clinical trials 2004-2015.

BACKGROUND: Improvements in pediatric cancer survival are attributed to cooperative clinical trials. Under-representation of specific demographic groups has been described in adult and pediatric cancer trials and poses a threat to the generalizability of results. An evaluation of data provided by the Children's Oncology Group (COG) of upfront trial enrollment for US patients 0 to 29 years old between 2004 and 2015 was performed. METHODS: US cancer cases were estimated using incidence data and US population estimates from the Surveillance, Epidemiology, and End Results Program and compared to observed COG cases. Percent enrollment and standardized ratios of enrollment were calculated across demographic, disease, and socioeconomic groups. The COG website was utilized to quantify available trials and assess age eligibility. RESULTS: 19.9% of estimated US cancer patients age 0 to 19 years enrolled on COG trials. Younger patients were more represented across diseases and races/ethnicities. Patients with hematologic malignancies were more represented compared to solid and central nervous system (CNS) tumors. CONCLUSION: COG trial enrollment rates are declining when compared to previously published data, potentially from challenges in pediatric drug development, difficulty designing feasible trials for highly curable diagnoses, and issues ensuring trial availability for the heterogeneous group of solid and CNS tumors. Though racial/ethnic groups and county-level socioeconomic factors were proportionally represented, under representation of the adolescent/young adult (AYA) population and younger patients with solid and CNS tumors remains a concern. Targeted efforts should focus on these subgroups and further research should evaluate AYA enrollment rates across all available trials.

Pulmonary toxicity in paediatric patients with relapsed or refractory Hodgkin lymphoma receiving brentuximab vedotin.

Brentuximab vedotin (Bv) is becoming increasingly important in the treatment of Hodgkin lymphoma (HL), with improved outcomes and an overall favourable toxicity profile. However, Bv is associated with severe pulmonary toxicity when combined with bleomycin, suggesting that additive toxicity may be an important consideration. Furthermore, little has been published on tolerability in paediatric patients. We retrospectively evaluated the occurrence of pulmonary toxicity of Bv in 19 paediatric and young adult patients with relapsed or refractory HL. Patient characteristics, baseline health status, treatment regimens including cumulative doses of Bv, bleomycin, gemcitabine, radiation and carmustine, and the occurrence of pulmonary toxicity were collected. Seven (36·8%) of the 19 patients were treated with Bv. The odds of pulmonary toxicity were 4·0-fold higher (95% confidence interval 0·55-29·18) in patients exposed to Bv compared to unexposed patients in univariate analysis (P = 0·17). Similar results were found in multivariable analysis. Pulmonary toxicity occurred frequently in our cohort and was more common in patients who received Bv than in patients who did not receive Bv, although this was not statistically significant. Because patients with HL are exposed to a myriad of therapies with potential for pulmonary toxicity, continuing to evaluate the risk associated with Bv is critical.