Systemic Exposure to Thiopurines and Risk of Relapse in Children With Acute Lymphoblastic Leukemia: A Children's Oncology Group Study

Additive effects of TPMT and NUDT15 on thiopurine toxicity in children with acute lymphoblastic leukemia across multiethnic populations

BACKGROUND

Thiopurines such as mercaptopurine (MP) are widely used to treat acute lymphoblastic leukemia (ALL). Thiopurine-S-methyltransferase (TPMT) and Nudix hydrolase 15 (NUDT15) inactivate thiopurines, and no-function variants are associated with drug-induced myelosuppression. Dose adjustment of MP is strongly recommended in patients with intermediate or complete loss of activity of TPMT and NUDT15. However, the extent of dosage reduction recommended for patients with intermediate activity in both enzymes is currently not clear.

METHODS

MP dosages during maintenance were collected from 1768 patients with ALL in Singapore, Guatemala, India, and North America. Patients were genotyped for TPMT and NUDT15, and actionable variants defined by the Clinical Pharmacogenetics Implementation Consortium were used to classify patients as TPMT and NUDT15 normal metabolizers (TPMT/NUDT15 NM), TPMT or NUDT15 intermediate metabolizers (TPMT IM or NUDT15 IM), or TPMT and NUDT15 compound intermediate metabolizers (TPMT/NUDT15 IM/IM). In parallel, we evaluated MP toxicity, metabolism, and dose adjustment using a Tpmt/Nudt15 combined heterozygous mouse model (Tpmt+/-/Nudt15+/-).

RESULTS

Twenty-two patients (1.2%) were TPMT/NUDT15 IM/IM in the cohort, with the majority self-reported as Hispanics (68.2%, 15/22). TPMT/NUDT15 IM/IM patients tolerated a median daily MP dose of 25.7 mg/m2 (interquartile range = 19.0-31.1 mg/m2), significantly lower than TPMT IM and NUDT15 IM dosage (P < .001). Similarly, Tpmt+/-/Nudt15+/- mice displayed excessive hematopoietic toxicity and accumulated more metabolite (DNA-TG) than wild-type or single heterozygous mice, which was effectively mitigated by a genotype-guided dose titration of MP.

CONCLUSION

We recommend more substantial dose reductions to individualize MP therapy and mitigate toxicity in TPMT/NUDT15 IM/IM patients.

Feasibility pilot trial of a tailored medication adherence-promotion intervention for adolescents and young adults with cancer: Study design and protocol

BACKGROUND

Medication non-adherence is common among adolescents and young adults (AYAs) with cancer and associated with poor health outcomes. AYAs with cancer endorse multiple barriers to adherence that differ across individuals, suggesting that tailoring intervention content to an AYA's specific barriers may have the potential to improve adherence. The purpose of this manuscript is to report on ORBIT-guided Phase I design efforts to create the first tailored adherence-promotion intervention for AYAs with cancer and the study protocol for the ongoing Phase II pilot feasibility trial.

METHODS

Phase I design included qualitative interviews (n = 15 AYAs) to understand patient preferences for adherence-promotion care, development and refinement of a best-worst scaling exercise barriers tool (n = 5 AYAs), and development of intervention modules and a tailoring algorithm. In the ongoing Phase II pilot feasibility trial, AYAs (ages 15-24 years) with cancer currently taking oral chemotherapy or prophylactic medication will be recruited from three children's hospitals. Feasibility, acceptability, and usability will be assessed and these outcomes along with data on medication adherence will be used to inform the next phases of intervention development and testing.

CONCLUSIONS

If promising, this program of research ultimately has the potential to equip clinicians with additional strategies for supporting adherence among AYAs with cancer. NCT05706610.

Association of NUDT15 gene polymorphism with adverse reaction, treatment efficacy, and dose of 6-mercaptopurine in patients with acute lymphoblastic leukemia: a systematic review and meta-analysis

6-mercaptopurine (6-MP) serves as the backbone in the maintenance regimens of acute lymphoblastic leukemia (ALL). We aimed to evaluate the influence of NUDT15 gene polymorphism on the risk of myelosupression, hepatotoxicity and interruption of 6-MP, as well as treatment efficacy and dose of 6-MP in ALL patients. A total of 24 studies with 3,374 patients were included in this meta-analysis. We found 9-fold higher risk of 6-MP induced leukopenia (odds ratio [OR] =9.00, 95% confidence interval [CI]: 3.73-21.74) and 2.5-fold higher risk of 6-MP-induced neutropenia (OR=2.52, 95% CI: 1.72-3.69) for NUDT15 c.415C>T variant carriers in the dominant model. Moreover, we found that the dose intensity of 6-MP in ALL patients with one NUDT15 c.415C>T variant alleles (CT) was 19% less than that in wild-type patients (CC) (mean differences: 19.43%, 95% CI: -25.36 to -13.51). The tolerable dose intensity of 6-MP in NUDT15 c.415C>T homozygote variant (TT) and heterozygote variant (CT) carriers was 49% and 15% less than that in wild-type patients, respectively. The NUDT15 c.415C>T variant group (CT+TT) had seven times (OR=6.98, 95% CI: 2.83-17.22) higher risk of developing 6-MP intolerance than the CC group. However, NUDT15 c.415C>T polymorphism did not appear significantly associated with hepatotoxicity, treatment interruption or relapse incidence. We concluded that NUDT15 c.415C>T was a good predictor for 6-MP-induced myelosuppression in ALL patients. The dose intensity of 6-MP in ALL patients with NUDT15 c.415C>T variants was significantly lower than that in wild-type patients. This research provided a basis for further investigation into relations between NUDT15 gene and adverse reaction, treatment efficacy and dose intensity of 6-MP.

Histidine re-sensitizes pediatric acute lymphoblastic leukemia to 6-mercaptopurine through tetrahydrofolate consumption and SIRT5-mediated desuccinylation

Despite progressive improvements in the survival rate of pediatric B-cell lineage acute lymphoblastic leukemia (B-ALL), chemoresistance-induced disease progression and recurrence still occur with poor prognosis, thus highlighting the urgent need to eradicate drug resistance in B-ALL. The 6-mercaptopurine (6-MP) is the backbone of ALL combination chemotherapy, and resistance to it is crucially related to relapse. The present study couples chemoresistance in pediatric B-ALL with histidine metabolism deficiency. Evidence was provided that histidine supplementation significantly shifts the 6-MP dose-response in 6-MP-resistant B-ALL. It is revealed that increased tetrahydrofolate consumption via histidine catabolism partially explains the re-sensitization ability of histidine. More importantly, this work provides fresh insights into that desuccinylation mediated by SIRT5 is an indispensable and synergistic requirement for histidine combination therapy against 6-MP resistance, which is undisclosed previously and demonstrates a rational strategy to ameliorate chemoresistance and protect pediatric patients with B-ALL from disease progression or relapse.

Bioequivalence study followed by model-informed dose optimization of a powder for oral suspension of 6-mercaptopurine

BACKGROUND

6-Mercaptopurine (6MP) is the mainstay chemotherapy for acute lymphoblastic leukemia (ALL) and is conventionally available as 50 mg tablets. A new 6MP powder for oral suspension (PFOS 10 mg/mL) was developed recently by IDRS Labs, India, intended for pediatric use. A comparative pharmacokinetics of PFOS with T. mercaptopurine was conducted to determine the dose equivalence.

METHODS

An open-label, randomized, two-treatment, two-period, two-sequence, single oral dose, crossover, bioequivalence study was conducted on 51 healthy adult subjects. Post hoc, a population pharmacokinetic (PopPK) model was developed using the healthy volunteer data to perform simulations with various PFOS doses and select a bioequivalent dose. Further, to confirm the safety of PFOS in pediatrics, a simulation of 6MP and 6-thioguanine exposures was performed by incorporating the formulation-specific parameters derived from the healthy volunteer study into the PopPK model in childhood ALL available in literature.

RESULTS

The 6MP PFOS had 47% higher oral bioavailability compared to the reference product. Simulations using a two-compartmental PopPK model with dissolution and transit compartments showed that 40 mg of PFOS was found to be equivalent to 50 mg tablets. The simulated 6-thioguanine nucleotide concentrations in children using the dose adjusted for PFOS were between 114 and 703.6 pmol/8 × 108 RBC, which was within the range reported in pediatric ALL studies.

CONCLUSION

6MP PFOS 10 mg/mL should be administered at a 20% lower dose than the tablet to achieve comparable exposure. 6MP PFOS addresses an unmet medical need for a liquid formulation of 6MP in the Indian subcontinent.

COVID-19 in Pediatric Patients With Acute Lymphoblastic Leukemia or Lymphoma

Importance

COVID-19 in pediatric patients with acute lymphoblastic leukemia or lymphoma (ALL/LLy) has not been described in detail and may affect chemotherapy administration and long-term outcomes.

Objective

To describe the clinical presentation of COVID-19 and chemotherapy modifications in pediatric patients with ALL/LLy.

Design, Setting, and Participants

This is a retrospective case series of patients at St Jude Children's Research Hospital and its affiliate sites with newly diagnosed ALL/LLy who were treated on the Total XVII protocol (NCT03117751) between March 30, 2020, and June 20, 2022. Participants included patients aged 1 to 18 years who were receiving protocol chemotherapy. Acute symptoms and chemotherapy modifications were evaluated for 60 days after the COVID-19 diagnosis, and viral clearance, adverse events, and second SARS-CoV-2 infections were followed up during the 27-month study period.

Exposures

SARS-CoV-2; all patients were screened at least weekly and at symptom onset and/or after known exposure to SARS-CoV-2.

Main Outcomes and Measures

Description of the spectrum of COVID-19 illness and chemotherapy modifications.

Results

Of 308 pediatric patients, 110 (36%) developed COVID-19 at a median age of 8.2 (IQR, 5.3-14.5) years. Sixty-eight patients (62%) were male. Most patients were in the continuation/maintenance phase of chemotherapy (101 [92%]). Severe disease was rare (7 [6%]) but was associated with older age, higher white blood cell counts at ALL/LLy diagnosis, lower absolute lymphocyte counts at COVID-19 diagnosis, abnormal chest imaging findings, and SARS-CoV-2 reinfection. Rare but serious thrombotic events included pulmonary embolism and cerebral venous sinus thrombosis (n = 1 for each). No multisystem inflammatory syndrome in children or death was seen. SARS-CoV-2 reinfection occurred in 11 patients (10%) and was associated with older age and with receiving standard or high-risk vs low-risk ALL/LLy therapy. Chemotherapy interruptions occurred in 96 patients (87%) and were longer for patients with severe disease, SARS-CoV-2 reinfection, and/or a COVID-19 diagnosis during the pre-Omicron variant period vs the post-Omicron period (after December 27, 2021).

Conclusions and Relevance

In this case series of COVID-19 in pediatric patients with ALL/LLy, severe COVID-19 was rare, but chemotherapy administration was affected in most patients. Long-term studies are needed to establish the outcomes of COVID-19 in this population.

Effect of carvedilol versus placebo on cardiac function in anthracycline-exposed survivors of childhood cancer (PREVENT-HF): a randomised, controlled, phase 2b trial

BACKGROUND

Carvedilol improves cardiac function in patients with heart failure but remains untested as cardioprotective therapy in long-term childhood cancer survivors (ie, those who have completed treatment for childhood cancer and are in remission) at risk for heart failure due to high-dose anthracycline exposure. We aimed to evaluate the activity and safety of low-dose carvedilol for heart failure risk reduction in childhood cancer survivors at highest risk for heart failure.

METHODS

PREVENT-HF was a randomised, double-blind, phase 2b trial done at 30 hospitals in the USA and Canada. Patients were eligible if they had any cancer diagnosis that resulted in at least 250 mg/m2 cumulative exposure to anthracycline by age 21 years; completed their cancer treatment at least 2 years previously; an ejection fraction of at least 50% or fractional shortening of at least 25%, or both; and bodyweight of at least 40 kg. Patients were randomly assigned (1:1) with automated computer-generated permuted block randomisation (block size of 4), stratified by age at diagnosis, time since diagnosis, and history of chest-directed radiotherapy, to carvedilol (up-titrated from 3·125 g per day to 12·5 mg per day) or placebo orally for 2 years. Participants, staff, and investigators were masked to study group allocation. The primary endpoint was to establish the effect of carvedilol on standardised left ventricular wall thickness-dimension ratio Z score (LVWT/Dz). Treatment effects were analysed with a linear mixed-effects model for normally distributed data with a linear time effect and testing the significance of treatment*time interaction in the modified intention-to-treat (mITT) cohort (ie, all randomly assigned participants who had a baseline and at least one subsequent echocardiogram measurement). Safety was assessed in the ITT population (ie, all randomly assigned participants). This trial was registered with ClinicalTrials.gov, NCT027175073, and enrolment and follow-up are complete.

FINDINGS

Between July 3, 2012, and June 22, 2020, 196 participants were enrolled, of whom 182 (93%) were eligible and randomly assigned to either carvedilol (n=89) or placebo (n=93; ITT population). Median age was 24·7 years (IQR 19·6-36·6), 91 (50%) participants were female, 91 (50%) were male, and 119 (65%) were non-Hispanic White. As of data cutoff (June 10, 2022), median follow-up was 725 days (IQR 378-730). 151 (n=75 in the carvedilol group and n=76 in the placebo group) of 182 participants were included in the mITT population, among whom LVWT/Dz was similar between the two groups (-0·14 [95% CI -0·43 to 0·16] in the carvedilol group vs -0·45 [-0·77 to -0·13] in the placebo group; difference 0·31 [95% CI -0·10 to 0·73]; p=0·14). Two (2%) of 89 patients in the carvedilol group two adverse events of grade 2 or higher (n=1 shortness of breath and n=1 arthralgia) and none in the placebo group. There were no adverse events of grade 3 or higher and no deaths.

INTERPRETATION

Low-dose carvedilol appears to be safe in long-term childhood cancer survivors at risk for heart failure, but did not result in significant improvement of LVWT/Dz compared with placebo. These results do not support the use of carvedilol for secondary heart failure prevention in anthracycline-exposed childhood cancer survivors.

FUNDING

National Cancer Institute, Leukemia & Lymphoma Society, St Baldrick's Foundation, Altschul Foundation, Rally Foundation, American Lebanese Syrian Associated Charities.

Profound Hypoglycemia and High Anion Gap Metabolic Acidosis in a Pediatric Leukemic Patient Receiving 6-Mercaptopurine

A 13-year-old male undergoing maintenance chemotherapy with methotrexate and 6-mercaptopurine (6MP), for very high-risk B-cell acute lymphoblastic leukemia (ALL), presented with vomiting due to severe hypoglycemia with metabolic acidosis. While his laboratory values were concerning for a critically ill child, the patient was relatively well appearing. Hypoglycemia is a rare but serious side effect of 6MP with an unexpectedly variable presentation; therefore, a high index of suspicion is needed for its prompt detection and treatment. This patient also had severe metabolic acidosis, likely secondary to hypoglycemia, creating a serious clinical picture despite a well-appearing child. This example of incongruity between laboratory tests and clinical appearance adds nuance to the existing literature. Moreover, although 6MP-associated hypoglycemia is rare, it may be more prevalent than the literature suggests, as symptoms of hypoglycemia-nausea, vomiting, and somnolence-mirror common chemotherapy side effects. 6MP-induced hypoglycemia can be ameliorated with the addition of allopurinol to shunt metabolism in favor of the production of therapeutic metabolites over hepatotoxic metabolites. Additionally, a morning administration of 6MP and frequent snacks may also help to prevent hypoglycemia. Overall, this case adds to the literature of unusual reactions to 6MP including hypoglycemia in an older child without traditional risk factors.

Maintenance Treatment in Acute Lymphoblastic Leukemia: A Clinical Primer

Cure rates in pediatric acute lymphoblastic leukemia (ALL) currently approach 90% in the developed world. Treatment involves 6-8 mo of intensive multi-drug chemotherapy followed by 24 mo of maintenance treatment (ALL-MT). The cornerstone of ALL-MT is the daily administration of oral 6-mercaptopurine (6MP), a purine analogue. 6MP is combined with weekly oral methotrexate (MTX), an antifolate drug, to augment therapeutic activity. Some protocols include additional chemotherapy drugs (such as vincristine and corticosteroids) during MT. The objective of ALL-MT is to ensure uninterrupted treatment at the highest tolerated doses of 6MP and MTX. This requires periodic adjustments of 6MP and MTX doses throughout treatment. Tolerance is determined through regular clinical assessments and careful monitoring of blood counts. Tolerated drug doses vary widely among patients, influenced by genetic and non-genetic factors, and require individualized dosing. Suboptimal treatment intensity in ALL-MT is associated with inferior outcomes and results from failure to treat at highest tolerated drug doses and/or interruptions in treatment due to non-adherence or toxicity. Management of MT thus requires close supervision to ensure treatment adherence, periodic drug dose modifications, and treatment to tolerance, while minimizing treatment interruptions due to toxicity. The review highlights these challenges and discusses approaches and strategies for the management of MT, focusing on the Indian context.

Polypharmacy and medication fill nonadherence in a population-based sample of adolescent and young adult cancer survivors, 2008-2017

PURPOSE

We examined the association between polypharmacy-an established risk factor for nonadherence in the elderly-and medication fill nonadherence in a large national sample of adolescent and young adult cancer survivors (AYAs) in the USA.

METHODS

We pooled data (2008-2017) from the Medical Expenditure Panel Survey. We defined polypharmacy as ≥ 3 unique medications prescribed, based on self-report and pharmacy data, and medication fill nonadherence as self-reported delay or inability to obtain a necessary medication. We estimated prevalence of medication fill nonadherence among AYAs (age 18-39 years with a cancer history). We used logistic regression to estimate the association between (1) polypharmacy and medication fill nonadherence in AYAs, and (2) total number of medications prescribed and medication fill nonadherence, controlling for sex, number of chronic conditions, disability, and survey year.

RESULTS

AYAs (n = 598) were predominantly female (76.2%), age 30-39 years (64.9%), and non-Hispanic White (72.1%). Nearly half were poor (19.0%) or near-poor/low income (21.6%). One in ten AYAs reported medication fill nonadherence (9.75%). Of these, more than 70% cited cost-related barriers as the reason. AYAs with polypharmacy had 2.49 times higher odds of medication fill nonadherence (95%CI 1.11-5.59), compared to those without polypharmacy. Odds of medication fill nonadherence increased by 16% with each additional medication prescribed (AOR 1.16, 95% CI 1.07-1.25).

CONCLUSIONS

Polypharmacy may be an important risk factor for medication fill nonadherence in AYAs in the USA.

IMPLICATIONS FOR CANCER SURVIVORS

Improving AYAs' medication adherence requires eliminating cost-related barriers, particularly for those with polypharmacy.

Impact of Mercaptopurine Metabolites on Disease Outcome in the AIEOP-BFM ALL 2009 Protocol for Acute Lymphoblastic Leukemia

In the maintenance phase of Associazione Italiana di Ematologia e Oncologia Pediatrica (AIEOP)- Berlin-Frankfurt-Muenster (BFM) acute lymphoblastic leukemia (ALL) 2009 protocol, mercaptopurine (MP) is given at the planned dose of 50 mg/m2 /day; however, dose adjustments are routinely performed to target patients' white blood cells to the optimal range of 2,000-3,000 cells/μL. Pediatric patients with ALL (n = 290, age: median (1st-3rd quartile): 4.8 (3.0-8.1) years; boys: 56.9%) were enrolled mainly in 4 medium-large Italian pediatric hospitals; 14.1% of patients relapsed after a median (1st-3rd quartile) follow-up time of 4.43 (3.82-5.46) years from maintenance beginning. MP metabolites (thionucleotide (TGN) and methyl-derivatives (MMPN)) were measured in the erythrocytes of 387 blood samples of 200 patients by high performance liquid chromatography with ultraviolet detection. Single-nucleotide polymorphisms (SNPs; (rs1800462, rs1800460, and rs1142345 in TPMT gene, rs116855232 in NUDT15, rs1127354, rs7270101, rs6051702 in ITPA, and rs2413739 in PACSIN2) were characterized by Taqman SNP genotyping assays. Cox proportional hazard models did not show an impact of TGN levels and variability on relapse. In contrast, after multivariate analysis, relapse hazard ratio (HR) increased in children with ALL of the intermediate risk arm compared with those in standard risk arm (3.44, 95% confidence interval (CI), 1.31-9.05, P = 0.012), and in carriers of the PACSIN2 rs2413739 T allele compared with those with the CC genotype (heterozygotes CT: HR, 2.32, 95% CI, 0.90-5.97, P = 0.081; and homozygous TT: HR, 4.14, 95% CI, 1.54-11.11, P = 0.005). Future studies are needed to confirm the lack of impact of TGN levels and variability on relapse in the AIEOP-BFM ALL trials, and to clarify the mechanism of PACSIN2 rs2413739 on outcome.

Poverty and relapse risk in children with acute lymphoblastic leukemia: a Children's Oncology Group study AALL03N1 report

The association between individual-level poverty and relapse in children receiving maintenance treatment for acute lymphoblastic leukemia (ALL) remains unclear. In a secondary analysis of COG-AALL03N1, we used data from US Census Bureau to categorize patients living below year-specific federal poverty thresholds, calculated using self-reported annual household income and size of household. Participants with federal poverty thresholds above 120% of their yearly household income were categorized as living in extreme poverty. Hazard of relapse was estimated using multivariable proportional subdistributional hazards regression for patients living in extreme poverty while receiving ALL maintenance therapy after adjusting for relevant predictors. Among 592 patients in this analysis, 12.3% of the patients were living in extreme poverty. After a median follow-up of 7.9 years, the cumulative incidence of relapse at 3 years from study enrollment among those living in extreme poverty was significantly higher (14.3%) than those not living in extreme poverty (7.6%). Multivariable analysis demonstrated that children living in extreme poverty had a 1.95-fold greater hazard of relapse than those not living in extreme poverty; this association was mitigated after the inclusion of race/ethnicity in the model, likely because of collinearity between race/ethnicity and poverty. A greater proportion of children living in extreme poverty were nonadherent to mercaptopurine (57.1% vs 40.9%); however, poor adherence did not completely explain the association between poverty and relapse risk. Future studies need to understand the mechanisms underlying the association between extreme poverty and relapse risk. This trial was registered at www.clinicaltrials.gov as #NCT00268528.

Building new standards to prevent harm from medication errors in children with cancer

Children with cancer receive many medications outside the hospital administered by their caregivers. The study by Walsh et al. shows the number and types of medication errors in these patients. The study includes data from three different centers. Importantly, the study shows the types of errors that cause harm. The authors describe how the harmful errors can be prevented. We suggest ways these results can be used to identify which patients and families will benefit from additional attention. Providing more help at clinic and in the home may help prevent harmful medication errors in children with cancer.

Barriers to medication adherence among adolescents and young adults with cancer

BACKGROUND

Adherence promotion is a critical component of adolescent and young adult (AYA) cancer care, but predictors of nonadherence that could be targeted in intervention efforts remain largely unknown. The purpose of this multi-site longitudinal observational study was to examine the relationship between barriers and medication adherence among AYAs with cancer.

PROCEDURE

Sixty-five AYAs (ages 15-24 years; mean age = 18.97 years, SD = 2.51; Mmean time since diagnosis = 1.42 years, SD = 1.95) with newly diagnosed or relapsed cancer completed self-report measures of barriers and adherence at quarterly study visits and used an electronic adherence monitoring device for 12 months. Longitudinal mixed effects models were used to examine our primary hypothesis that greater barriers are related to lower adherence over time. Descriptive statistics were used to explore our secondary aim of describing the frequency and patterns of barriers endorsed by AYAs with cancer.

RESULTS

After controlling for covariates (time, medication type, race, ethnicity, diagnosis, time since diagnosis), a greater number of barriers was associated with lower electronically monitored (β = -5.99, p = .005) and self-reported (β = -1.92, p < .001) adherence. The specific barriers endorsed by AYAs differed across participants, and the majority of AYAs endorsed an entirely different pattern of barriers than any other AYA in the study.

CONCLUSION

Barriers are associated with nonadherence and may be a promising target for intervention. Individual variability across barriers, however, suggests that tailoring may be necessary, and a promising next step is to explore personalized approaches to adherence promotion.

EBV-driven lymphoid neoplasms associated with pediatric ALL maintenance therapy

The development of a second malignancy after the diagnosis of childhood acute lymphoblastic leukemia (ALL) is a rare event. Certain second malignancies have been linked with specific elements of leukemia therapy, yet the etiology of most second neoplasms remains obscure and their optimal management strategies are unclear. This is a first comprehensive report of non-Hodgkin lymphomas (NHLs) following pediatric ALL therapy, excluding stem-cell transplantation. We analyzed data of patients who developed NHL following ALL diagnosis and were enrolled in 12 collaborative pediatric ALL trials between 1980-2018. Eighty-five patients developed NHL, with mature B-cell lymphoproliferations as the dominant subtype (56 of 85 cases). Forty-six of these 56 cases (82%) occurred during or within 6 months of maintenance therapy. The majority exhibited histopathological characteristics associated with immunodeficiency (65%), predominantly evidence of Epstein-Barr virus-driven lymphoproliferation. We investigated 66 cases of post-ALL immunodeficiency-associated lymphoid neoplasms, 52 from our study and 14 additional cases from a literature search. With a median follow-up of 4.9 years, the 5-year overall survival for the 66 patients with immunodeficiency-associated lymphoid neoplasms was 67.4% (95% confidence interval [CI], 56-81). Five-year cumulative risks of lymphoid neoplasm- and leukemia-related mortality were 20% (95% CI, 10.2-30) and 12.4% (95% CI, 2.7-22), respectively. Concurrent hemophagocytic lymphohistiocytosis was associated with increased mortality (hazard ratio, 7.32; 95% CI, 1.62-32.98; P = .01). A large proportion of post-ALL lymphoid neoplasms are associated with an immunodeficient state, likely precipitated by ALL maintenance therapy. Awareness of this underrecognized entity and pertinent diagnostic tests are crucial for early diagnosis and optimal therapy.

Adherence to Oral Chemotherapy in Acute Lymphoblastic Leukemia during Maintenance Therapy in Children, Adolescents, and Young Adults: A Systematic Review

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and young adults. Treatment is long and involves 2-3 years of a prolonged maintenance phase composed of oral chemotherapies. Adherence to these medications is critical to achieving good outcomes. However, adherence is difficult to determine, as there is currently no consensus on measures of adherence or criteria to determine nonadherence. Furthermore, there have been few studies in pediatric B-ALL describing factors associated with nonadherence. Thus, we performed a systematic review of literature on oral chemotherapy adherence during maintenance therapy in ALL following PRISMA guidelines. Published studies demonstrated various objective and subjective methods of assessing adherence without generalizable definitions of nonadherence. However, the results of these studies suggested that nonadherence to oral maintenance chemotherapy was associated with increased risk of relapse. Future studies of B-ALL therapy should utilize a uniform assessment of adherence and definitions of nonadherence to better determine the impact of nonadherence on B-ALL outcomes and identify predictors of nonadherence that could yield targets for adherence improving interventions.

Body mass index during maintenance therapy and relapse risk in children with acute lymphoblastic leukemia: A Children's Oncology Group report

BACKGROUND

Obesity at diagnosis of childhood acute lymphoblastic leukemia (ALL) is associated with greater risk of relapse; whether this association extends to obesity during maintenance is unstudied.

METHODS

This study used data from AALL03N1 to calculate median body mass index (BMI) for 676 children over 6 consecutive months during maintenance therapy; BMI percentile (BMI%ile) were operationalized as normal/underweight (<85%ile), overweight/obese (85%-98%ile), and extreme obesity (≥99%ile). Hazard of relapse was estimated using multivariable proportional subdistributional hazards regression after adjusting for all relevant demographic and clinical predictors.

RESULTS

Median age at study enrollment was 6 years and median length of follow-up was 7.9 years. Overall, 43.3% of the cohort was underweight/normal weight, 44.8% was overweight/obese, and 11.8% had extreme obesity. Cumulative incidence of relapse at 4 years from study enrollment was higher among those with extreme obesity (13.6% ± 4.5%) compared to those with underweight/normal weight (9.0% ± 2.1%). Multivariable analysis revealed that children with extreme obesity had a 2.4-fold (95% confidence interval [CI], 1.1-5.0; p = .01) greater hazard of relapse compared to those who were underweight/normal weight. Overweight/obese patients were at comparable risk to those who were underweight/normal weight (hazard ratio, 0.8; 95% CI, 0.4-1.6). Erythrocyte thioguanine nucleotide (TGN) levels were significantly lower among children with extreme obesity compared to those with underweight/normal weight (141.6 vs. 168.8 pmol/8 × 108 erythrocytes; p = .0002), however, the difference in TGN levels did not explain the greater hazard of relapse among those with extreme obesity.

CONCLUSIONS

Extreme obesity during maintenance therapy is associated with greater hazard of relapse in children with ALL. Underlying mechanisms of this association needs further investigation.

LAY SUMMARY

Findings from this study demonstrate that extreme obesity during maintenance therapy is associated with a greater hazard of relapse among children with acute lymphoblastic leukemia. We show that children with obesity have lower levels of erythrocyte thioguanine nucleotides even after adjusting for adherence to oral chemotherapy. However, these lower levels do not explain the greater hazard of relapse, paving the way for future studies to explore this association.

Infectious events in pediatric patients with acute lymphoblastic leukemia/lymphoma undergoing evaluation for fever without severe neutropenia

BACKGROUND

Infections cause significant treatment-related morbidity during pediatric acute lymphoblastic leukemia/lymphoma (ALL/LLy) therapy. Fevers during periods without severe neutropenia are common, but etiologies are not well-described. This study sought to describe the bloodstream infection (BSI) and non-BSI risk in children undergoing therapy for ALL/LLy.

METHODS

Demographic and clinical data were abstracted for febrile episodes without severe neutropenia at two children's hospitals. Treatment courses were stratified by intensity. Multivariate logistic regression evaluated characteristics associated with infection.

RESULTS

There were 1591 febrile episodes experienced by 524 patients. Of these, 536 (34%) episodes had ≥1 infection; BSI occurred in 30 (1.9%) episodes. No BSIs occurred in episodes with a recent procedural sedation or cytarabine exposure. Presence of hypotension, chills/rigors, higher temperature, and infant phenotype were independently associated with BSI (p < .05). Of the 572 non-BSIs, the most common was upper respiratory infection (URI) (n = 381, 67%). Compared to episodes without infection, URI symptoms, higher temperature, absolute neutrophil count 500-999/μl, and evaluation during a low-intensity treatment course were more likely to be associated with a non-BSI (p < .05) and inpatient status was less likely to be associated with a non-BSI (p < .05).

CONCLUSIONS

The BSI rate in pediatric patients with ALL/LLy and fever without severe neutropenia is low, but one-third of the time, patients have a non-BSI. Future research should test if the need for empiric antibiotics can be tailored based on the associations identified in this study.

[Practical management during maintenance therapy of pediatric acute lymphoblastic leukemia: Recommendations of the French Society for Childhood and Adolescent Cancer and Leukemia (SFCE)]

Maintenance therapy is the last phase of treatment for acute lymphoblastic leukemia in children and adolescents. Although maintenance therapy is associated with toxicities and specific management issues, it is an essential phase of treatment that reduces the risk of relapse. The objective of this work is to propose a guide for the initiation, administration, and monitoring of maintenance therapy, and for the management of food, schooling, leisure, community life, risk of infection and links with family medicine.

Optimizing thiopurine therapy in children with acute lymphoblastic leukemia: A promising “MINT” sequencing strategy and therapeutic “DNA-TG” monitoring

Thiopurines, including thioguanine (TG), 6-mercaptopurine (6-MP), and azathioprine (AZA), are extensively used in clinical practice in children with acute lymphoblastic leukemia (ALL) and inflammatory bowel diseases. However, the common adverse effects caused by myelosuppression and hepatotoxicity limit their application. Metabolizing enzymes such as thiopurine S-methyltransferase (TPMT), nudix hydrolase 15 (NUDT15), inosine triphosphate pyrophosphohydrolase (ITPA), and drug transporters like multidrug resistance-associated protein 4 (MRP4) have been reported to mediate the metabolism and transportation of thiopurine drugs. Hence, the single nucleotide polymorphisms (SNPs) in those genes could theoretically affect the pharmacokinetics and pharmacological effects of these drugs, and might also become one of the determinants of clinical efficacy and adverse effects. Moreover, long-term clinical practices have confirmed that thiopurine-related adverse reactions are associated with the systemic concentrations of their active metabolites. In this review, we mainly summarized the pharmacogenetic studies of thiopurine drugs. We also evaluated the therapeutic drug monitoring (TDM) research studies and focused on those active metabolites, hoping to continuously improve monitoring strategies for thiopurine therapy to maximize therapeutic efficacy and minimize the adverse effects or toxicity. We proposed that tailoring thiopurine dosing based on MRP4, ITPA, NUDT15, and TMPT genotypes, defined as “MINT” panel sequencing strategy, might contribute toward improving the efficacy and safety of thiopurines. Moreover, the DNA-incorporated thioguanine nucleotide (DNA-TG) metabolite level was more suitable for red cell 6-thioguanine nucleotide (6-TGNs) monitoring, which can better predict the efficacy and safety of thiopurines. Integrating the panel “MINT” sequencing strategy with therapeutic “DNA-TG” monitoring would offer a new insight into the precision thiopurine therapy for pediatric acute lymphoblastic leukemia patients.

Day-to-Day Decision Making by Adolescents and Young Adults with Cancer

Background: Adolescents and young adults (AYAs) with cancer must negotiate the transition between childhood and adulthood while dealing with a life-threatening illness. AYA involvement in decision making varies depending on the type of decision and when decisions occur during treatment, and evidence suggests that AYAs want to be involved in decision making. Objective: To explore involvement of AYAs with cancer in day-to-day decisions affected by their cancer and treatment. Methods: This qualitative study used interpretive focused ethnography within the sociologic tradition, informed by symbolic interactionism. Semi-structured interviews and informal participant observation took place at two quaternary pediatric oncology programs. Results: Thirty-one interviews were conducted with 16 AYAs ages 15 to 20 years. Major day to day decision-making categories identified included: (1) mental mindset, (2) self-care practices, (3) self-advocacy, and (4) negotiating relationships. Participants described how they came to grips with their illness early on and decided to fight their cancer. They described decisions they made to protect their health, how they advocated for themselves and decisions they made about relationships with family and friends. Conclusions: Through day-to-day decisions, participants managed the impact of cancer and its treatment on their daily lives. Research should focus on developing and implementing interventions to empower AYAs to participate in day-to-day decisions that will affect how they manage their cancer, its treatment and ultimately their outcomes. Implications for Practice: Healthcare providers can facilitate AYA's participation in day-to-day decision making through encouraging autonomy and self-efficacy by providing support and through effective communication.

Socioeconomic position and maintenance therapy in children with acute lymphoblastic leukemia: A national cohort study

BACKGROUND

Socioeconomic differences in survival among children with acute lymphoblastic leukemia (ALL) have been reported in high-income countries and there is an unmet need for strategies to identify vulnerable patient subgroups. Reported differences in survival for children from families with different socioeconomic positions seem to arise when starting maintenance therapy. This could reflect reduced physician's compliance or family adherence to maintenance therapy.

METHODS

This nationwide cohort study with extensive monitoring of systemic methotrexate (MTX)/6-mercaptopurine (6MP) dosing and metabolite levels, retrospectively investigated 173 Danish children treated according to The Nordic Society for Pediatric Hematology and Oncology ALL2008 protocol from 2008 to 2016.

RESULTS

Significantly lower prescribed doses of MTX and 6MP were seen in the children in families with short parental education (short vs. medium vs. higher education: mMTX: 13.8, 16.2, and 18.6 mg/m² /week; p < .01; m6MP: 47.4, 64.9, and 66.1 mg/m² /day; p = .03) or parents unemployed/not in workforce (unemployed/not in workforce vs. mixed vs. at work: mMTX: 15.0, 19.9, and 17.2 mg/m² /week; p < .01; m6MP: 54.8, 72.0, and 65.1 mg/m² /day; p < .01). When assessing family adherence by analyzing MTX and 6MP metabolite levels, including per prescribed dose of MTX and 6MP, we found no significant differences by levels of parental education, affiliation to work market, or income (p > .05 for all comparisons).

CONCLUSIONS

These results indicate that inferior physician compliance to protocol recommendations on drug dosage rather than families' adherence to therapy may contribute to the association between socioeconomic position and cure rates in childhood ALL, although precise mechanisms remain to be explored.

A systematic review of adherence to anticoagulation regimens in pediatric patients

Thromboembolic disease rates are increasing in pediatric patients. Anticoagulation is prescribed for treatment and prevention of thromboembolic disease. While nonadherence to anticoagulation regimens predicts poor health outcomes in adults, data in anticoagulated pediatric patients are limited. We systematically reviewed the rates, outcomes, and predictors of anticoagulation nonadherence in the pediatric population. Out of a total of 3581 unique articles identified for review, 17 studies met inclusion criteria. These studies primarily evaluated patients with cardiac disease treated with vitamin K antagonists. Overall nonadherence rates varied from 3% to 42%, based upon population, definition of adherence, and measurement strategy. Patient age, goal international normalized ratio (INR), and number of concurrent potentially interacting medications correlated with nonadherence. Data examining the relationship between nonadherence and health outcomes were included in only two studies. Limitations of current literature, as well as critical knowledge gaps that require future study, are discussed.

Maintenance therapy for acute lymphoblastic leukemia: basic science and clinical translations

Maintenance therapy (MT) with oral methotrexate (MTX) and 6-mercaptopurine (6-MP) is essential for the cure of acute lymphoblastic leukemia (ALL). MTX and 6-MP interfere with nucleotide synthesis and salvage pathways. The primary cytotoxic mechanism involves the incorporation of thioguanine nucleotides (TGNs) into DNA (as DNA-TG), which may be enhanced by the inhibition of de novo purine synthesis by other MTX/6-MP metabolites. Co-medication during MT is common. Although Pneumocystis jirovecii prophylaxis appears safe, the benefit of glucocorticosteroid/vincristine pulses in improving survival and of allopurinol to moderate 6-MP pharmacokinetics remains uncertain. Numerous genetic polymorphisms influence the pharmacology, efficacy, and toxicity (mainly myelosuppression and hepatotoxicity) of MTX and thiopurines. Thiopurine S-methyltransferase (encoded by TPMT) decreases TGNs but increases methylated 6-MP metabolites (MeMPs); similarly, nudix hydrolase 15 (encoded by NUDT15) also decreases TGNs available for DNA incorporation. Loss-of-function variants in both genes are currently used to guide MT, but do not fully explain the inter-patient variability in thiopurine toxicity. Because of the large inter-individual variations in MTX/6-MP bioavailability and metabolism, dose adjustments are traditionally guided by the degree of myelosuppression, but this does not accurately reflect treatment intensity. DNA-TG is a common downstream metabolite of MTX/6-MP combination chemotherapy, and a higher level of DNA-TG has been associated with a lower relapse hazard, leading to the development of the Thiopurine Enhanced ALL Maintenance (TEAM) strategy-the addition of low-dose (2.5-12.5 mg/m²/day) 6-thioguanine to the 6-MP/MTX backbone-that is currently being tested in a randomized ALLTogether1 trial (EudraCT: 2018-001795-38). Mutations in the thiopurine and MTX metabolism pathways, and in the mismatch repair genes have been identified in early ALL relapses, providing valuable insights to assist the development of strategies to detect imminent relapse, to facilitate relapse salvage therapy, and even to bring about changes in frontline ALL therapy to mitigate this relapse risk.

Effect of Treatment in a Specialized Pediatric Hemato-Oncology Setting on 5-Year Survival in Acute Lymphoblastic Leukemia: A Quasi-Experimental Study

Simple Summary

Adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) have a worse prognosis than children. In addition to differences in biology—such as higher incidence of unfavorable genetic alterations in the AYA population—this might be related to the fact that ALL patients under a certain age (often 18 years) are generally treated in special pediatric hemato-oncology settings, which is associated with improved survival, while patients above that age are treated in adult hemato-oncology care settings. Based on previous research, adult treatment settings have increasingly adopted pediatric-inspired protocols, which appear to have led to increased survival of adolescent ALL patients. This study aims to assess whether there remains an effect of treatment of ALL patients in a specialized pediatric hemato-oncology setting on 5-year survival. This study provides insight into the effects of such treatment for ALL patients, and may stimulate further research into causal relationships in other oncological conditions.

Abstract

Survival rates of adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) are inferior to those of pediatric ALL patients. In part, this may be caused by differences in treatment setting. Generally, children are treated in specialized pediatric hemato-oncology settings, whereas AYAs are treated in adult hemato-oncology settings. Since 2005, adult treatment protocols have included pediatric-inspired chemotherapy, which has been the standard of care for AYAs from 2008 onwards. This study aims to assess whether, despite protocols in both settings having become more similar, there remains an effect of treatment in specialized pediatric hemato-oncology settings on 5-year survival for ALL patients in the Netherlands. We used nationwide registry data (2004–2013) on 472 ALL patients aged between 10 and 30 years old. A fuzzy regression discontinuity design was applied to estimate the treatment effect using two-stage least squares regression with the treatment threshold at 17 years and 7 months of age, adjusting for sex, age at diagnosis, and immunophenotype. We found a risk difference of 0.419 (p = 0.092; 95% CI = −0.0686; 0.907), meaning a 41.9 percentage point greater probability of surviving five years after diagnosis for ALL patients treated in specialized pediatric hemato-oncology settings. Our results suggest that ALL patients around the threshold could benefit from increased collaboration between pediatric and adult hemato-oncology in terms of survival.

Thiopurine Enhanced ALL Maintenance (TEAM): study protocol for a randomized study to evaluate the improvement in disease-free survival by adding very low dose 6-thioguanine to 6-mercaptopurine/methotrexate-based maintenance therapy in pediatric and adult patients (0-45 years) with newly diagnosed B-cell precursor or T-cell acute lymphoblastic leukemia treated according to the intermediate risk-high group of the ALLTogether1 protocol

Background

A critical challenge in current acute lymphoblastic leukemia (ALL) therapy is treatment intensification in order to reduce the relapse rate in the subset of patients at the highest risk of relapse. The year-long maintenance phase is essential in relapse prevention. The Thiopurine Enhanced ALL Maintenance (TEAM) trial investigates a novel strategy for ALL maintenance.

Methods

TEAM is a randomized phase 3 sub-protocol to the ALLTogether1 trial, which includes patients 0–45 years of age with newly diagnosed B-cell precursor or T-cell ALL, and stratified to the intermediate risk-high (IR-high) group, in 13 European countries. In the TEAM trial, the traditional methotrexate (MTX)/6-mercaptopurine (6MP) maintenance backbone (control arm) is supplemented with low dose (2.5–12.5 mg/m²/day) oral 6-thioguanine (6TG) (experimental arm), while the starting dose of 6MP is reduced from 75 to 50 mg/m²/day. A total of 778 patients will be included in TEAM during ~ 5 years. The study will close when the last included patient has been followed for 5 years from the end of induction therapy. The primary objective of the study is to significantly improve the disease-free survival (DFS) of IR-high ALL patients by adding 6TG to 6MP/MTX-based maintenance therapy. TEAM has 80% power to detect a 7% increase in 5-year DFS through a 50% reduction in relapse rate. DFS will be evaluated by intention-to-treat analysis. In addition to reducing relapse, TEAM may also reduce hepatotoxicity and hypoglycemia caused by high levels of methylated 6MP metabolites. Methotrexate/6MP metabolites will be monitored and low levels will be reported back to clinicians to identify potentially non-adherent patients.

Discussion

TEAM provides a novel strategy for maintenance therapy in ALL with the potential of improving DFS through reducing relapse rate. Potential risk factors that have been considered include hepatic sinusoidal obstruction syndrome/nodular regenerative hyperplasia, second cancer, infection, and osteonecrosis. Metabolite monitoring can potentially increase treatment adherence in both treatment arms.

Trial registration

EudraCT, 2018–001795-38. Registered 2020-05-15,

Clinicaltrials.gov, NCT04307576. Registered 2020-03-13, https://clinicaltrials.gov/ct2/show/NCT04307576

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09522-3.

Utilization of Thiopurine Metabolites and Allopurinol in Pediatric Acute Lymphoblastic Leukemia: Consideration for an Algorithmic Approach

Persistently elevated absolute neutrophil counts during maintenance for acute lymphoblastic leukemia is a risk factor for relapse and may be related to wild-type thiopurine methyltransferase activity and overly efficient shunting of 6-mercaptopurine to hepatotoxic metabolites (6-methylmercaptopurine nucleotides), leading to low 6-thioguanine nucleotides. 6-mercaptopurine is also metabolized by xanthine oxidase, and therefore allopurinol, an inhibitor of xanthine oxidase, allows for increased 6-thioguanine nucleotides and decreased 6-methylmercaptopurine nucleotide. Here, we report our experience with allopurinol for persistently elevated absolute neutrophil count or hepatotoxicity and suggest an algorithmic approach for checking thiopurine metabolites and initiating allopurinol in acute lymphoblastic leukemia maintenance.

Perceptions of parents of pediatric patients with acute lymphoblastic leukemia on oral chemotherapy administration: A qualitative analysis

OBJECTIVE

To describe the experiences and perspectives of parents of pediatric patients with acute lymphoblastic leukemia (ALL) regarding oral chemotherapy administration during maintenance therapy.

METHODS

English-speaking parents of patients 4 to <18 years who were receiving ALL maintenance oral chemotherapy were eligible to participate in this mixed methods study. Using semi-structured interviews, we asked participants how difficult they found oral chemotherapy administration. We also probed regarding barriers and facilitators of oral chemotherapy administration and strategies used to overcome challenges. Lastly, we asked participants for their advice to future parents giving oral chemotherapy to their children.

RESULTS

Twenty-three participants were interviewed. One-fifth of participants stated that oral chemotherapy administration at home was hard or very hard. Common factors influencing oral chemotherapy administration were product-related (e.g., formulation) and treatment-related adverse effects (e.g., nausea), lifestyle adjustment (e.g., fitting in with family schedule), and attitudes (e.g., onus of medication administration). Strategies to address oral chemotherapy administration included several administration techniques, scheduling of medication administration, and normalization of medication taking.

CONCLUSIONS

Oral chemotherapy administration during ALL maintenance therapy was hard for some parents. Identification of these parents and discussion of strategies to facilitate adherence to oral chemotherapy regimens may optimize patient outcomes.

NUDT15 is a key genetic factor for prediction of hematotoxicity in pediatric patients who received a standard low dosage regimen of 6-mercaptopurine

6-Mercaptopurine (6-MP) is commonly used for treatment of acute lymphoblastic leukemia (ALL). The incidence of hematotoxicity caused by this drug is quite high in Asians even using a standard low dosage regimen. The present study was aimed to elucidate the impact of thiopurine S-methyltransferase (TPMT), a nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15), inosine triphosphatase (ITPA) and ATP Binding Cassette Subfamily C Member 4 (ABCC4) polymorphisms on hematotoxicity in pediatric patients who received a standard low starting dose of 6-MP. One hundred and sixty-nine pediatric patients were enrolled and their genotypes were determined. Patients who carried NUDT15^∗3 and NUDT15^∗2 genotypes were at a 10-15 fold higher risk of severe neutropenia than those of the wild-type during the early months of the maintenance phase. Risk of neutropenia was not significantly increased in patients with other NUDT15 variants as well as in patients with TPMT, ITPA or ABCC4 variants. These results suggest that NUDT15 polymorphisms particularly, NUDT15^∗3 and NUDT15^∗2, play major roles in 6-MP-induced severe hematotoxicity even when using a standard low dosage of 6-MP and genotyping of these variants is necessary in order to obtain precise tolerance doses and avoid severe hematotoxicity in pediatric patients.

Association between adherence to oral therapies in cancer patients and clinical outcome: A systematic review of the literature

AIMS

Adherence to therapy is a key factor in successful treatment. The aim of this systematic review is to assess the extent to which patients with better adherence to oral therapy have better clinical outcomes among cancer patients.

METHODS

All studies published in PubMed up to 20 October 2020, which considered the use of oral anticancer drugs for cancer patients and which correlated treatment adherence with a clinical outcome, were considered.

RESULTS

From the 42 studies considered in the systematic review, 14 were for oncological indications and 28 for haematological indications. There was considerable variance in calculation methods, outcomes considered, and in the definitions of adherence. However, it emerged that most studies reported a significant correlation between adherence to therapy and clinical outcome.

CONCLUSION

As adherence to therapy is a key factor in achieving a better clinical outcome, future studies with large samples, robust endpoints and the use of at least two methods of assessing adherence would be desirable in order to produce more robust evidence.

Parents' Experiences with Home-Based Oral Chemotherapy Prescribed to a Child Diagnosed with Acute Lymphoblastic Leukemia: A Qualitative Study

Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children. Treatment includes home-based oral chemotherapies (OCs) (e.g., 6-mercaptopurine and dexamethasone) taken for 2 to 3 years. The management of OC can be challenging for children and their parents. However, the multifaceted experience of families with children taking OC for ALL is largely undescribed. We report the experience with these OCs from the parents’ perspective. We conducted a qualitative descriptive study. Semi-structured interviews were conducted with the parents of children with ALL aged < 15 years, followed in a specialized university-affiliated center. The interviews were fully transcribed and thematically analyzed. Thirteen of the seventeen eligible parents (76.5%) participated in the study. The parents’ motivation to follow the recommendations provided by the multidisciplinary care team regarding OC was very high. The quantity and the quality of the information received were judged adequate, and the parents reported feeling knowledgeable enough to take charge of the OC at home. Adapting to the consequences of OC on family daily life was collectively identified as the biggest challenge. This includes developing and maintaining a strict daily routine, adapting to the child’s neurobehavioral changes during dexamethasone days and adapting family social life. Our findings have several implications for enhancing the support offered to families with home-based OC for ALL. Supportive interventions should consider the family as a whole and their needs should be regularly monitored. Specific attention should be paid to the development and maintenance of a routine, to the parental burden, and to the emotional impact, especially regarding dexamethasone.

Cytotoxic and antitumoral activity of N-(9H-purin-6-yl) benzamide derivatives and related water-soluble prodrugs

BACKGROUND

The development of small molecules as cancer treatments is still of both interest and importance.

OBJECTIVE

Having synthesized and identified the initial cytotoxic activity of a series of chemically related N-(9H-purin-6-yl) benzamide derivatives, we continued their evaluation on cancer cell models. We also synthesized water-soluble prodrugs of the main compound and performed in vivo experiments.

METHOD

We used organic chemistry to obtain compounds of interest and prodrugs. The biological evaluation included MTT assays, synergy experiments, proliferation assays by CFSE, cell cycle distribution and in vivo antitumoral activity.

RESULTS

Our results show activities on cancer cell lines ranging from 3-39 µM for the best compounds, with both induction of apoptosis and decrease in cell proliferation. Two compounds evaluated in vivo showed weak antitumoral activity. In addition, the lead compound and its prodrug had a synergistic activity with the nucleoside analogue fludarabine in vitro and in vivo.

CONCLUSION

Our work allowed us to gain better knowledge on the activity of N-(9H-purin-6-yl) benzamide derivatives and showed new examples of water-soluble prodrugs. More research is warranted to decipher the molecular mechanisms of the molecules.

NUDT15 c.415C>T Polymorphism Predicts 6-MP Induced Early Myelotoxicity in Patients with Acute Lymphoblastic Leukemia Undergoing Maintenance Therapy

Purpose

Severe myelosuppression in patients with acute lymphoblastic leukemia (ALL) undergoing 6-MP-based maintenance therapy is attributed to TPMT gene polymorphisms, which is rare in Asian populations. This study aims to evaluate the role of selected polymorphisms in NUDT15, ITPA, and MRP4 genes in addition to TPMT in predicting 6-MP intolerance during ALL maintenance therapy.

Patients and Methods

We screened for the presence of NUDT15*3 (c.415 C>T, rs116855232); MRP4 c.2269 C>T (rs3765534), ITPA c.94 C>A (rs1127354) polymorphisms in addition to TPMT *2 (rs1800462), *3A (*3B and *3C; rs1800460 and rs1142345) in ALL patients with documented severe neutropenia (cohort-1; n=42). These polymorphisms were then screened in a prospective cohort of ALL patients (cohort-2; n=133) and compared with 6-MP dose reduction, early/late myelotoxicity.

Results

Nineteen (45%) patients in cohort-1 and 18 (14%) in cohort-2 had NUDT15 c.415 C>T variant while 4 (3%) patients in cohort-2 had TPMT*3C variant. Five (12%) in cohort-1 and 30 (24%) in cohort-2 had ITPA c.94 C>A variant while 9 (22%) and 15 (12%) had MRP4 c.2269 C>T variant in cohorts-1 and 2, respectively. All in cohort-1 and 36 (27%) in cohort-2 had severe myelotoxicity. Twenty-eight patients (66.6%) in cohort-1 and 40 (30%) patients in cohort-2 had significant 6-MP dose reduction. NUDT15 c.415 C>T variant explained severe myelotoxicity in 63% and 33% in cohort 1 and 2. TPMT*3C and ITPA c.94 C>A variants also explained myelotoxicity in cohort-2 (Median ANC: 376 vs 1014 mm³; p=0.04 and 776 vs 1023 mm³; p=0.04 respectively). NUDT15 c.415 C>T polymorphism explained significant myelotoxicity (507 vs 1298 mm³; p<0.0001) in the multivariate analysis as well (β=−0.314, p<0.0001).

Conclusion

NUDT15 c.415 C>T (15*3), TPMT*3C, as well as ITPA c.94 C>A and MRP4 c.2269 C>T polymorphisms explain hematotoxicities. Preemptive genotype-based (NUDT15*3, TPMT, ITPA c.94 C>A) 6-MP dosing could improve the outcome after maintenance therapy.

Prevalence of non-adherence and non-compliance during maintenance therapy in adults with acute lymphoblastic leukemia and their associations with survival

OBJECTIVES

Explore patient adherence and physician compliance to protocol guidelines during maintenance therapy, including the association with survival in adults with acute lymphoblastic leukemia (ALL).

METHODS

Blood counts, aminotransferase levels and prescribed 6-mercaptopurine (6MP)/methotrexate (MTX) doses were compared with the protocol guidelines to assess compliance. Non-adherence to the prescribed medication was confirmed in patients with unmeasurable 6MP metabolite levels and suspected in patients with low 6MP metabolites concurrent with aminotransferase and white blood cell count within normal ranges, while potential intermittent non-adherence was defined by >1.9 fold fluctuating 6MP metabolites.

RESULTS

Physicians' non-compliance with insufficient dose increments of 6MP/MTX despite white blood cell counts above the target level comprised a median of 20.1% (interquartile range 9.7-39.3%) of the observed time in maintenance therapy, yet no association to relapse was found (P = .17). Non-adherence to 6MP was confirmed in 9.8% (5 of 51 patients), suspected in an additional 9.8% (5 of 51 patients), and intermittent non-adherence was suspected in 52.6% (20 of 38 patients).

CONCLUSION

Although no association between non-compliance and leukemic relapse was found, likely due to lack of power, increased attention to this phase of ALL therapy is indicated.

Understanding thiopurine methyltransferase polymorphisms for the targeted treatment of hematologic malignancies

INTRODUCTION

Thiopurine methyltransferase (TPMT) catalyzes the S-methylation of thiopurines (mercaptopurine (MP) and tioguanine (TG)), chemotherapeutic agents used in the treatment of acute lymphoblastic leukemia (ALL). Polymorphisms in TPMT gene encode diminished activity enzyme, enhancing accumulation of active metabolites, and partially explaining the inter-individual differences in patients' clinical response.

AREAS COVERED

This review gives an overview on TPMT gene and function, and discusses the pharmacogenomic implications of TPMT variants in the prevention of severe thiopurine-induced hematological toxicities and the less known implication on TG-induced sinusoidal obstruction syndrome. Additional genetic and non-genetic factors impairing TPMT activity are considered. Literature search was done in PubMed for English articles published since1990, and on PharmGKB.

EXPERT OPINION

To titrate thiopurines safely and effectively, achieve the right degree of lymphotoxic effect and avoid excessive myelosuppression, the optimal management will combine a preemptive TPMT genotyping to establish a safe initial dose with a close phenotypic monitoring of TPMT activity and/or of active metabolites during long-term treatment. Compared to current ALL protocols, replacement of TG by MP during reinduction phase in TPMT heterozygotes and novel individualized TG regimens in maintenance for TPMT wild-type subjects could be investigated to improve outcomes while avoiding risk of severe hepatotoxicity.

Comprehensive analysis of dose intensity of acute lymphoblastic leukemia chemotherapy

Chemotherapy dosages are often compromised, but most reports lack data on dosages that are actually delivered. In two consecutive acute lymphoblastic leukemia trials that differed in their asparaginase formulation, native E. coli L-asparaginase in St. Jude Total 15 (T15, n=365) and pegaspargase in Total 16 (T16, n=524), we tallied the dose intensities for all drugs on the low-risk or standard-risk arms, analyzing 504,039 dosing records. The median dose intensity for each drug ranged from 61-100%. Dose intensities for several drugs were more than 10% higher on T15 than on T16: cyclophosphamide (P<0.0001 for the standard- risk arm), cytarabine (P<0.0001 for the standard-risk arm), and mercaptopurine (P<0.0001 for the low-risk arm and P<0.0001 for the standardrisk arm). We attributed the lower dosages on T16 to the higher asparaginase dosages on T16 than on T15 (P<0.0001 for both the low-risk and standard-risk arms), with higher dose-intensity for mercaptopurine in those with anti-asparaginase antibodies than in those without (P=5.62x10^{- 3} for T15 standard risk and P=1.43x10^-4 for T16 standard risk). Neutrophil count did not differ between protocols for low-risk patients (P=0.18) and was actually lower for standard-risk patients on T16 than on T15 (P<0.0001) despite lower dosages of most drugs on T16. Patients with low asparaginase dose intensity had higher methotrexate dose intensity with no impact on prognosis. The only dose intensity measure predicting a higher risk of relapse on both studies was higher mercaptopurine dose intensity, but this did not reach statistical significance (P=0.03 T15; P=0.07 T16). In these intensive multiagent trials, higher dosages of asparaginase compromised the dosing of other drugs for acute lymphoblastic leukemia, particularly mercaptopurine, but lower chemotherapy dose intensity was not associated with relapse.

Individual prediction of nonadherence to oral mercaptopurine in children with acute lymphoblastic leukemia: Results from COG AALL03N1

BACKGROUND

Poor mercaptopurine (6MP) adherence (mean adherence rate < 90%) increases the relapse risk among children with acute lymphoblastic leukemia (ALL). 6MP adherence remains difficult to measure in real time. Easily measured patient-level factors could identify patients at risk for poor adherence.

METHODS

The authors measured 6MP adherence via electronic monitoring for 6 months per patient. Using data from month 3, they created a risk prediction model for 6MP nonadherence in 407 children with ALL (mean age, 7.7 ± 4.4 years); they used receiver operating characteristic analyses in the training set (n = 250) and replicated this in the test set (n = 157).

RESULTS

Age, race/ethnicity, 6MP dose intensity, absolute neutrophil count, 6MP ingestion patterns, and household structure were retained in the prediction model. The model yielded areas under the receiver operating characteristic curve (AUCs) of 0.79 (95% confidence interval [CI], 0.71-0.85) and 0.74 (95% CI, 0.63-0.85) in the training and test sets, respectively. The model performed better for those who were ≥12 years old (AUC, 0.79; 95% CI, 0.59-0.99) than those <12 years old (AUC, 0.70; 95% CI, 0.58-0.81). Using the predicted probability of nonadherence based on receiver operating characteristic analysis, the authors developed a binary risk classifier to classify patients with a high or low probability of nonadherence. The sensitivity and specificity of the binary risk classifier were 71% and 76%, respectively. Adjusted for clinical prognosticators, the risk of relapse was 2.2-fold higher (95% CI, 0.94-5.1; P = .07) among patients with a high probability of nonadherence in comparison with those with a low probability, as identified by the risk prediction model.

CONCLUSIONS

The risk prediction model identified patients with a high probability of nonadherence and could be used in real time to personalize recommendations and interventions in the clinic.

LAY SUMMARY

The vast majority of children with acute lymphoblastic leukemia, the most common childhood cancer, are cured. The treatment of acute lymphoblastic leukemia includes taking an oral chemotherapy medicine (mercaptopurine) for approximately 2 years. Children who miss doses of this medicine (specifically children who take the medicine less than 90% of the time that it is prescribed) are more likely to suffer leukemia relapse. The authors of this article have measured mercaptopurine adherence with electronic bottle caps to determine characteristics of patients that predict nonadherence, and they have created a prediction tool that could allow physicians to identify and intervene with patients at high risk of nonadherence.

Bone marrow inhibition induced by azathioprine in a patient without mutation in the thiopurine S-methyltransferase pathogenic site: A case report

BACKGROUND

Azathioprine (AZA) and its close analog 6-mercaptopurine are thiopurines widely used in the treatment of patients with cancer, organ transplantation, and autoimmune or inflammatory diseases, including systemic lupus erythematosus. Bone marrow inhibition is a common side effect of AZA, and severe bone marrow inhibition is related to decreased thiopurine S-methyltransferase (TPMT) activity.

CASE SUMMARY

We herein report a patient with proliferative lupus nephritis who was using AZA for maintenance therapy, had no common TPMT pathogenic site mutations, and exhibited severe bone marrow inhibition on the 15^th day after oral administration.

CONCLUSION

This report alerts physicians to the fact that even though the TPMT gene has no common pathogenic site mutation, severe myelosuppression may also occur.

The Effect of NUDT15, TPMT, APEX1, and ITPA Genetic Variations on Mercaptopurine Treatment of Pediatric Acute Lymphoblastic Leukemia

Mercaptopurine (MP) is a commonly used maintenance regimen for childhood acute lymphoblastic leukemia (ALL). However, 6-MP has a narrow therapeutic index, which causes dose-limiting toxicities in hematopoietic tissues. Recent studies reported several candidate pharmacogenetic markers such as TPMT, NUDT15, ITPA, and APEX1, which predict the possibility of 6-MP related toxicities. The aim of this study is to evaluate the effect of major variants of these genes on 6-MP intolerances and toxicities in pediatric acute lymphoblastic leukemia (ALL) patients. A total of 83 pediatric ALL patients were included (56 males and 27 females). The NUDT15 c.415C>T (rs116855232), NUDT15 c.55_56insGAGTCG (rs746071566), ITPA c.94C>A (rs1127354), ITPA c.IVS2+21A>C (rs7270101), APEX c.190A>G (rs2307486), and TPMT variants were analyzed by sanger sequencing. Correlations between indexes of 6-MP-related toxicities or 6-MP intolerance (absolute neutrophil count [ANC] at several time point, days of ANC < 1 × 10³/mm³, days of ANC < 0.5 × 10³/mm³, frequency of febrile neutropenia, maximum AST and ALT, 6-MP dose and 6-MP dose intensity during maintenance therapy) and genetic variations were analyzed. The NUDT15 c.415C>T allele carrier showed significantly low 6-MP doses at the final maintenance therapy period than the wild type carrier (p = 0.007). The 6-MP dose intensities at the sixth and final maintenance period were also significantly low in NUDT15 c.415C>T carriers (p = 0.003 and 0.008, respectively). However, indexes for neutropenia, days of febrile neutropenia, maximum AST, and ALT levels were not associated with the presence of c.415C>T as well as other analyzed variants. When analyzing the effect of the coexistence of NUDT15 c.415C>T and ITPA c.94C>A, no significant differences were found between the NUDT15 c.415C>T carrier and carrier with both variations. The NUDT15 c.415C>T was the most useful marker to predict 6-MP intolerance among analyzed variants in our study population. Although we could not find association of those variants with 6-MP induced toxicities and the synergistic effects of those variants, a well-planed larger scale study would be helpful in clarifying new candidates and their clinical effects.

Access to Technology and Preferences for an mHealth Intervention to Promote Medication Adherence in Pediatric Acute Lymphoblastic Leukemia: Approach Leveraging Behavior Change Techniques

Background

Suboptimal adherence to 6-mercaptopurine (6-MP) is prevalent in pediatric acute lymphoblastic leukemia (ALL) and associated with increased risk of relapse. Rapid uptake of personal technology makes mobile health (mHealth) an attractive platform to promote adherence.

Objective

Study objectives were to examine access to mobile technology and preferences for an mHealth intervention to improve medication adherence in pediatric ALL.

Methods

A cross-sectional survey was administered in oncology clinic to parents of children with ALL as well as adolescents and young adults (AYAs) with ALL receiving maintenance chemotherapy.

Results

A total of 49 parents (median age [IQR] 39 [33-42] years; female 76% [37/49]) and 15 patients (median age [IQR] 17 [16-19]; male 80% [12/15]) participated. All parents and AYAs owned electronic tablets, smartphones, or both. Parents’ most endorsed mHealth app features included a list of medications (71%, 35/49), information about 6-MP (71%, 35/49), refill reminders (71%, 35/49), and reminders to take 6-MP (71%, 35/49). AYAs' most endorsed features included refill reminders (73%, 11/15), reminders to take 6-MP (73%, 11/15), and tracking 6-MP (73%, 11/15).

Conclusions

Parents and AYAs reported ubiquitous access to mobile technology and strong interest in multiple adherence-specific mHealth app features. Parents and AYAs provided valuable insight into preferred features for a multifunctional behavioral intervention (mHealth app) to promote medication adherence in pediatric ALL.

TPMT Genetic Variability and Its Association with Hematotoxicity in Indonesian Children with Acute Lymphoblastic Leukemia in Maintenance Therapy

PURPOSE

Hematotoxicity monitoring in children with acute lymphoblastic leukemia (ALL) is critical to preventing life-threatening infections and drug discontinuation. The primary drug that causes hematotoxicity in ALL children is 6-mercaptopurine (6-MP). Genetic variability of the drug-metabolizing enzymes of 6-MP, thiopurine S-methyltransferase (TPMT), is one factor that might increase the susceptibility of children to hematotoxicity. The present study aimed to determine the variability in TPMT genotypes and phenotypes and its association with the occurrence of hematotoxicity in ALL children in maintenance therapy.

PATIENTS AND METHODS

A cross-sectional study was conducted at Cipto Mangunkusumo and Dharmais National Cancer Hospital, Jakarta, Indonesia, from June 2017 to October 2018. We included ALL patients, 1-18 years, who were receiving at least one month of 6-MP during maintenance therapy according to the Indonesian protocol for ALL 2013. Direct sequencing was used to determine TPMT*3A, *3B, and *3C genotypes, and LC-MS/MS analysis was performed to measure the plasma concentrations of 6-MP and its metabolites. Association analysis between the TPMT genotype and hematotoxicity was evaluated using the unpaired t-test or Mann-Whitney's test.

RESULTS

The prevalence of neutropenia, anemia, and thrombocytopenia in ALL children during maintenance therapy was 51.9%, 44.3%, and 6.6%, respectively. We found a low frequency of TPMT*3C, which is 0.95%. No association was found between hematotoxicity and TPMT genotypes or age, nutritional status, serum albumin levels, risk stratification, the daily dose of 6-MP, and cotrimoxazole co-administration. However, hematotoxicity was associated with 6-methylmercaptopurine (6-MeMP) plasma concentrations and the ratio 6-MeMP/6-thioguanine (6-TGN). We also found no association between TPMT genotypes and TPMT phenotypes.

CONCLUSION

The 6-MeMP/6-TGN ratio is associated with hematotoxicity in ALL children during maintenance therapy but is not strong enough to predict hematotoxicity.

DNA-thioguanine nucleotide as a treatment marker in acute lymphoblastic leukemia patients with NUDT15 variant genotypes

Background

Large inter-individual variations in drug metabolism pose a challenge in determining 6-mercaptopurine (6MP) doses. As the last product of 6MP metabolism, DNA-thioguanine nucleotide (DNA-TGN) could reflect the efficacy of 6MP, especially in patients harboring variants in the 6MP metabolism pathway. The aim of this study was to investigate the clinical significance of DNA-TGN monitoring in Korean pediatric acute lymphoblastic leukemia (ALL) patients, focusing on the NUDT15 genotype.

Methods

The subjects of this study were patients who underwent ALL treatment with 6MP. Tests for the NUDT15 and TPMT genotypes were performed, and prospective DNA-TGN and erythrocyte TGN samples were collected after two weeks or more of 6MP treatment. DNA-TGN was quantified using the liquid chromatography-tandem mass spectrometry method.

Results

A total of 471 DNA-TGN measurements in 71 patients were analyzed, which ranged from 1.0 to 903.1 fmol thioguanine/μg DNA. The 6MP intensity demonstrated a significant relationship with DNA-TGN concentration (P<0.001). Patients harboring NUDT15 variants were treated with a lower dose of 6MP (P<0.001); however, there was no significant difference in DNA-TGN concentration when compared to patients carrying wild-type NUDT15 (P = 0.261). These patients also presented higher variation in DNA-TGN levels (P = 0.002) and DNA-TGN/6MP intensity (P = 0.019) compared to patients carrying wild-type NUDT15. DNA-TGN concentration did not show a significant correlation with WBC count (P = 0.093).

Conclusions

Patients harboring NUDT15 variants demonstrated similar DNA-TGN concentrations even at low doses of 6MP and showed high variability in DNA-TGN. Particularly in patients with NUDT15 variants who need a reduced 6MP dose, DNA-TGN could be applied as a useful marker to monitor the therapeutic effect of 6MP.

Excellent Outcomes With Reduced Frequency of Vincristine and Dexamethasone Pulses in Standard-Risk B-Lymphoblastic Leukemia: Results From Children's Oncology Group AALL0932

PURPOSE

AALL0932 evaluated two randomized maintenance interventions to optimize disease-free survival (DFS) while reducing the burden of therapy in children with newly diagnosed NCI standard-risk (SR) B-acute lymphoblastic leukemia (B-ALL).

METHODS

AALL0932 enrolled 9,229 patients with B-ALL; 2,364 average-risk (AR) patients were randomly assigned (2 × 2 factorial design) at the start of maintenance therapy to vincristine/dexamethasone pulses every 4 (VCR/DEX4) or every 12 (VCR/DEX12) weeks, and a starting dose of weekly oral methotrexate of 20 mg/m² (MTX20) or 40 mg/m² (MTX40).

RESULTS

Five-year event-free survival and overall survival (OS) from enrollment (with 95% CIs), for all eligible and evaluable SR B-ALL patients (n = 9,226), were 92.0% (91.1% and 92.8%) and 96.8% (96.2% and 97.3%), respectively. The 5-year DFS and OS from the start of maintenance for randomly assigned AR patients were 94.6% (93.3% and 95.9%) and 98.5% (97.7% and 99.2%), respectively. The 5-year DFS and OS for patients randomly assigned to receive VCR/DEX4 (n = 1,186) versus VCR/DEX12 (n = 1,178) were 94.1% (92.2% and 96.0%) and 98.3% (97.2% and 99.4%) v 95.1% (93.3% and 96.9%) and 98.6% (97.7% and 99.6%), respectively (P = .86 and .69). The 5-year DFS and OS for AR patients randomly assigned to receive MTX20 versus MTX40 were 95.1% (93.3% and 96.8%) and 98.8% (97.9% and 99.7%) v 94.2% (92.2% and 96.1%) and 98.1% (97.0% and 99.2%), respectively (P = .92 and .89).

CONCLUSIONS

The 0NCI-SR AR B-ALL who received VCR/DEX12 had outstanding outcomes despite receiving one third of the vincristine/dexamethasone pulses previously used as standard of care on Children's Oncology Group (COG) trials. The higher starting dose of MTX of 40 mg/m²/week did not improve outcomes when compared with 20 mg/m²/week. The decreased frequency of vincristine/dexamethasone pulses has been incorporated into frontline COG B-ALL trials to decrease the burden of therapy for patients and their families.

Antihypertensive Medication Adherence and Associated Factors: A Cross-Sectional Analysis of Patients Attending a National Referral Hospital in Asmara, Eritrea

BACKGROUND

Recent research suggests that poor adherence to antihypertensive medication (AHM) is a major problem in the management of hypertension. This study was therefore designed to evaluate the frequency of AHM and associated risk factors in patients attending a national referral hospital in Asmara, Eritrea.

METHODS

A total of 335 respondents (females: 222 (66.3%) participated in this cross-sectional study. Adherence to Medication was evaluated using a modified version of the Medication Adherence Report Scale (MARS). Additional data were abstracted from patients' medical records and a WHO STEPwise questionnaire.

RESULTS

The mean (±SD) age of the study participants was 59.65 (±12.20) years (females: 56.82 (±9.95) vs males: 57.17 (±9.60) years, p-value=0.001). Similarly, the median (IQR) for diastolic blood pressure (DBP) and systolic blood pressure (SBP) were 85.00 mmHg (IQR: 80.00-90.00 mmHg) and 145.00 mmHg (IQR: 130.00-160.00 mmHg), respectively. Overall, 246 (73.4%) and 244 (72.8%) participants had poor knowledge and poor adherence to AHM, respectively. In the multivariate analysis, factors associated with increased odds of poor adherence to AHM included sex (females: adjusted odds ratio (aOR): 4.95; 95% CI: 1.52-16.11, p value=0.008); employment status (Ref: employed/NGO) (self-employed: aOR: 1.95; 95% CI: 0.45-8.48, p-value=0.373) (housewife: aOR: 0.13; 95% CI: 0.04-0.413, p-value=0.001) (unemployed: aOR: 1.38; 95% CI:0.32-5.98; p-value=0.670); lack of attendance of health talk at the clinic (aOR: 2.33; 95% CI: 1.17-4.63; p-value=0.016); high cost of transportation (yes: aOR: 6.87; 95% CI: 3.25-14.52; p-value<0.001); knowledge (poor: aOR: 6.23; 95% CI: 2.36-18.05, p-value<0.001) and hypertension stage (Stage 3: aOR: 5.55; 95% CI, 1.44-21.37, p-value=0.013). Low level of knowledge regarding hypertension-related complications or associated risk factors was also noted.

CONCLUSION

The high level of poor adherence to anti-hypertension medications and low level of knowledge on hypertension should raise concern. Overall, decentralization of health care services and educational support are vital intervention pathways in this population.

Plasma imatinib levels and ABCB1 polymorphism influences early molecular response and failure-free survival in newly diagnosed chronic phase CML patients

Achieving early molecular response (EMR) has been shown to be associated with better event free survival in patients with chronic phase chronic myeloid leukemia (CP-CML) on Imatinib therapy. We prospectively evaluated the factors influencing the 2-year failure free survival (FFS) and EMR to imatinib therapy in these patients including day29 plasma Imatinib levels, genetic variants and the gene expression of target genes in imatinib transport and biotransformation. Patients with low and intermediate Sokal score had better 2-year FFS compared to those with high Sokal Score (p = 0.02). Patients carrying ABCB1-C1236T variants had high day29 plasma imatinib levels (P = 0.005), increased EMR at 3 months (P = 0.044) and a better 2 year FFS (P = 0.003) when compared to those with wild type genotype. This translates to patients with lower ABCB1 mRNA expression having a significantly higher intracellular imatinib levels (P = 0.029). Higher day29 plasma imatinib levels was found to be strongly associated with patients achieving EMR at 3 months (P = 0.022), MMR at 12 months (P = 0.041) which essentially resulted in better 2-year FFS (p = 0.05). Also, patients who achieved EMR at 3 months, 6 months and MMR at 12 months had better FFS when compared to those who did not. This study suggests the incorporation of these variables in to the imatinib dosing algorithm as predictive biomarkers of response to Imatinib therapy.

Pediatric acute lymphoblastic leukemia

The last decade has witnessed great advances in our understanding of the genetic and biological basis of childhood acute lymphoblastic leukemia (ALL), the development of experimental models to probe mechanisms and evaluate new therapies, and the development of more efficacious treatment stratification. Genomic analyses have revolutionized our understanding of the molecular taxonomy of ALL, and these advances have led the push to implement genome and transcriptome characterization in the clinical management of ALL to facilitate more accurate risk-stratification and, in some cases, targeted therapy. Although mutation- or pathway-directed targeted therapy (e.g., using tyrosine kinase inhibitors to treat Philadelphia chromosome [Ph]-positive and Phlike B-cell-ALL) is currently available for only a minority of children with ALL, many of the newly identified molecular alterations have led to the exploration of approaches targeting deregulated cell pathways. The efficacy of cellular or humoral immunotherapy has been demonstrated with the success of chimeric antigen receptor T-cell therapy and the bispecific engager blinatumomab in treating advanced disease. This review describes key advances in our understanding of the biology of ALL and optimal approaches to risk-stratification and therapy, and it suggests key areas for basic and clinical research.

Effects of NT5C2 Germline Variants on 6-Mecaptopurine Metabolism in Children With Acute Lymphoblastic Leukemia

6-mercaptopurine (6-MP) is widely used in the treatment of acute lymphoblastic leukemia (ALL), and its cytotoxicity is primarily mediated by thioguanine nucleotide (TGN) metabolites. A recent genomewide association study has identified germline polymorphisms (e.g., rs72846714) in the NT5C2 gene associated with 6-MP metabolism in patients with ALL. However, the full spectrum of genetic variation in NT5C2 is unclear and its impact on 6-MP drug activation has not been comprehensively examined. To this end, we performed targeted sequencing of NT5C2 in 588 children with ALL and identified 121 single nucleotide polymorphisms nominally associated with erythrocyte TGN during 6-MP treatment (P < 0.05). Of these, 61 variants were validated in a replication cohort of 372 children with ALL. After considering linkage disequilibrium and multivariate analysis, we confirmed two clusters of variants, represented by rs72846714 and rs58700372, that independently affected 6-MP metabolism. Functional studies showed that rs58700372 directly altered the activity of an intronic enhancer, with the variant allele linked to higher transcription activity and reduced 6-MP metabolism (lower TGN). By contrast, rs72846714 was not located in a regulatory element and instead its association signal was explained by linkage disequilibrium with a proximal functional variant rs12256506 that activated NT5C2 transcription in-cis. Our results indicated that NT5C2 germline variation significantly contributes to interpatient variability in thiopurine drug disposition.

Pharmacogenomics and ALL treatment: How to optimize therapy

Inherited genetic variations may alter drug sensitivity in patients with acute lymphoblastic leukemia, predisposing to adverse treatment side effects. In this review, we discuss evidence from children and young adults with acute lymphoblastic leukemia to review the available pharmacogenomic data with an emphasis on clinically actionable and emerging discoveries, for example, genetic variants in thiopurine methyltransferase and NUDT15 that alter 6-mercaptopurine dosing. We also highlight the need for ongoing pharmacogenomic research to validate the significance of recent findings. Further research in young adults, as well as with novel therapeutics, is needed to provide optimal therapy in future trials.

Standardized classification and framework for reporting, interpreting, and analysing medication non-adherence in cardiovascular clinical trials: a consensus report from the Non-adherence Academic Research Consortium (NARC)

Non-adherence has been well recognized for years to be a common issue that significantly impacts clinical outcomes and health care costs. Medication adherence is remarkably low even in the controlled environment of clinical trials where it has potentially complex major implications. Collection of non-adherence data diverge markedly among cardiovascular randomized trials and, even where collected, is rarely incorporated in the statistical analysis to test the consistency of the primary endpoint(s). The imprecision introduced by the inconsistent assessment of non-adherence in clinical trials might confound the estimate of the calculated efficacy of the study drug. Hence, clinical trials may not accurately answer the scientific question posed by regulators, who seek an accurate estimate of the true efficacy and safety of treatment, or the question posed by payers, who want a reliable estimate of the effectiveness of treatment in the marketplace after approval. The Non-adherence Academic Research Consortium is a collaboration among leading academic research organizations, representatives from the U.S. Food and Drug Administration and physician-scientists from the USA and Europe. One in-person meeting was held in Madrid, Spain, culminating in a document describing consensus recommendations for reporting, collecting, and analysing adherence endpoints across clinical trials. The adoption of these recommendations will afford robustness and consistency in the comparative safety and effectiveness evaluation of investigational drugs from early development to post-marketing approval studies. These principles may be useful for regulatory assessment, as well as for monitoring local and regional outcomes to guide quality improvement initiatives.

Optimal approach to the treatment of young adults with acute lymphoblastic leukemia in 2020

Akin to the introduction of tyrosine kinase inhibitors to Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL), pediatric-based asparaginase-heavy approaches have revolutionized the treatment of young adults with the Philadelphia chromosome-negative subset the past decades. Once again, we are approaching a new era. An era of precision medicine with immunotherapy and other molecularly targeted treatments that offers unique opportunities to customize treatment intensity with or without hematopoietic stem cell transplantation, reduce the burden of toxicities, and combat persistent residual disease. Recently approved agents for refractory/relapsed B-cell precursor ALL include the chimeric antigen receptor-modified T-cells, the anti-CD22 monoclonal antibody-drug conjugate, inotuzumab ozogamicin, and the bispecific anti-CD19 T-cell engager, blinatumomab. These agents are expected to move widely into the frontline setting along with the proteasome inhibitors, bortezomib and carfilzomib, as well as tyrosine kinase inhibitors for Philadelphia-like rearrangements that are especially frequent among young adults. To this add the BH3 mimetics, venetoclax and navitoclax, which are being widely explored in refractory/relapsed as well as frontline settings for B- and T-cell ALL. The promising anti-CD38 monoclonal antibody, daratumumab, is entering the scene of refractory/relapsed T-ALL, whereas the old purine analogue, nelarabine, is being evaluated in a new upfront setting. This review focuses on 2 main questions: How do we optimize frontline as well as salvage ALL treatment of young adults in the 2020s? Not least, how do we address the current burden of serious toxicities unique to young adults?