Using Pharmacology to Squeeze the Life Out of Childhood Leukemia, and Potential Strategies to Achieve Breakthroughs in Medulloblastoma Treatment

Bayesian modelling of response to therapy and drug-sensitivity in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a heterogeneous haematologic malignancy involving the abnormal proliferation of immature lymphocytes and accounts for most paediatric cancer cases. The management of ALL in children has seen great improvement in the last decades thanks to greater understanding of the disease leading to improved treatment strategies evidenced through clinical trials. Common therapy regimens involve a first course of chemotherapy (induction phase), followed by treatment with a combination of anti-leukemia drugs. A measure of the efficacy early in the course of therapy is the presence of minimal residual disease (MRD). MRD quantifies residual tumor cells and indicates the effiectiveness of the treatment over the course of therapy. MRD positivity is defined for values of MRD greater than 0.01%, yielding left-censored MRD observations. We propose a Bayesian model to study the relationship between patient features (leukemia subtype, baseline characteristics, and drug sensitivity profile) and MRD observed at two time points during the induction phase. Specifically, we model the observed MRD values via an auto-regressive model, accounting for left-censoring of the data and for the fact that some patients are already in remission after the first stage of induction therapy. Patient characteristics are included in the model via linear regression terms. In particular, patient-specific drug sensitivity based on ex vivo assays of patient samples is exploited to identify groups of subjects with similar profiles. We include this information as a covariate in the model for MRD. We adopt horseshoe priors for the regression coefficients to perform variable selection to identify important covariates. We fit the proposed approach to data from three prospective paediatric ALL clinical trials carried out at the St. Jude Children's Research Hospital. Our results highlight that drug sensitivity profiles and leukemic subtypes play an important role in the response to induction therapy as measured by serial MRD measures.

Cancer: slaying the nine-headed Hydra

Modern medicine continues to evolve, and the treatment armamentarium for various diseases grows more individualized across a breadth of medical disciplines. Cure rates for infectious diseases that were previously pan-fatal approach 100% because of the identification of the specific pathogen(s) involved and the use of appropriate combinations of drugs, where needed, to completely extinguish infection and hence prevent emergence of resistant strains. Similarly, with the assistance of technologies such as next-generation sequencing and immunomic analysis as part of the contemporary oncology armory, therapies can be tailored to each tumor. Importantly, molecular interrogation has revealed that metastatic cancers are distinct from each other and complex. Therefore, it is conceivable that rational personalized drug combinations will be needed to eradicate cancers, and eradication will be necessary to mitigate clonal evolution and resistance.

A Retrospective Cohort Study of the Efficacy, Safety, and Clinical Value of 6-TG versus 6-MP Maintenance Therapy in Children with Acute Lymphoblastic Leukemia

Objective

To explore the efficacy, safety, and clinical value of 6-TG versus 6-MP when treating childhood acute lymphoblastic leukemia (ALL).

Methods

The study period was from January 2017 to June 2021. The subjects of this study were 100 children with ALL who were treated in our hospital. According to different intervention methods, the children who received 6-MP maintenance therapy were selected as the control group, with a total of 57 cases. Children with TG maintenance therapy were included in the research group, a total of 43 cases. The ICNS recurrence rate, non-ICNS recurrence rate, first remission mortality rate, secondary malignant tumor, and other indicators were compared.

Results

First of all, we compared the effective rate: complete remission (CR), partial remission, and nonremission in the study group, and the effective rate was 87.5%. In the control group, there were CR, partial remission, and no remission, and the effective rate was 65.5%. The effective rate of the study group was higher, and the difference between groups was statistically significant (P < 0.05). There were 55 cases of failure in the study group, with an incidence of 21.91%. There were 42 cases of total failure events in the control group, the incidence rate was 18.02%, and there exhibited no remarkable difference (P > 0.05). In the study group, 6 cases died in the first remission, with a fatality rate of 2.39%, while there exhibited no death in the control group. The mortality in the first remission period in the study group was lower (P < 0.05). The overall recurrence rate of the study group was 5.57%, while that of the control group was 11.15%. The overall recurrence rate of the study group was lower, and the difference between groups was statistically significant (P < 0.05). The recurrence rate of ICNS was 2.14% in the study group and 2.98% in the control group, and there exhibited no remarkable difference (P > 0.05). The non-ICNS recurrence rate was 3.43% in the study group and 7.17% in the control group. There exhibited no remarkable difference (P > 0.05). The incidence of secondary malignant tumor events was 0.85% in the study group and 1.59% in the control group. There exhibited no remarkable difference (P > 0.05). The incidence of hepatic vein occlusive disease was 7.29% in the study group and 2.39% in the control group. The incidence of hepatic vein occlusive disease in the study group was higher, and the difference between groups was statistically significant (P < 0.05). Finally, we compared the incidence of adverse reactions. In the study group, there were 12 cases of oral mucosal damage, 7 cases of liver function damage, 6 cases of infection, 10 cases of myelosuppression, 9 cases of gastrointestinal reaction, and 4 cases of skin damage; the incidence rate was 23.17%. In the control group, there were 12 cases of oral mucosal damage, 7 cases of liver function damage, 6 cases of infection, 10 cases of myelosuppression, 9 cases of gastrointestinal reaction, and 4 cases of skin damage, with an incidence of 19.12%. There exhibited no remarkable difference in the incidence of adverse reactions (P > 0.05).

Conclusion

6-TG maintenance therapy in children with ALL can enhance the overall effective rate, can reduce the first remission mortality and the total recurrence rate, and will not increase the overall incidence of adverse reactions, but the incidence of reversible or irreversible hepatic veno-occlusive disease is remarkably increased, which has a certain clinical value.

Background

Treatment-related hepatotoxicity and myelosuppression remain formidable challenges for clinicians. Pharmacokinetic studies found that 6-TG has a more direct intracellular activation pathway, shorter cytotoxic time, and stronger potency than 6-MP. Therefore, this study investigated the efficacy, safety, and clinical value of 6-TG and 6-MP in the treatment of children with ALL.

The influence of MTHFR genetic polymorphisms on methotrexate therapy in pediatric acute lymphoblastic leukemia

MTHFR is a crucial enzyme in folate metabolism. This study aimed to determine the relationship between MTHFR genetic polymorphism and elimination and toxicities of methotrexate (MTX). To do that, the study enrolled 145 patients diagnosed with acute lymphoblastic leukemia, who received chemotherapy following the Chinese Children’s Cancer Group Acute Lymphoblastic Leukemia (CCCG-ALL)-2015 protocol (clinical trial number: ChiCTR-IPR-14005706). We analyzed the effects of MTHFR C677T and A1298C polymorphisms on MTX elimination and toxicities. Patients with the MTHFR C677T TT genotype could tolerate a significantly higher MTX dose than those with the CC/CT genotype. However, patients with C677T TT genotypes had an increased risk of hypokalemia (1.369 to CC and 1.409 to CT types). The MTX infusion rate in patients with the MTHFR A1298C AC genotype was slightly lower than that in those with CC or AA genotypes. Patients with the A1298C AA genotype had a 1.405-fold higher risk of hepatotoxicity than those with the AC genotype (P > 0.05). There was no significant difference between the prevalence of other toxicities among MTHFR C677T or A1298C genotypes (P > 0.05). Neither MTHFR C677T nor A1298C polymorphisms were significantly associated with delayed MTX clearance. To conclude, MTHFR polymorphisms were not good predictors of MTX-related toxicities.