Long-Term Outcomes of Modified St Jude Children's Research Hospital Total Therapy XIIIB and XV Protocols for Thai Children With Acute Lymphoblastic Leukemia

Treatment-related mortality in children with cancer in low-income and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Approximately 90% of children with cancer live in low-income and middle-income countries (LMICs), where 5-year survival is lower than 20%. Treatment-related mortality in high-income countries is approximately 3-5%; however, in LMICs, treatment-related mortality has been reported in up to 45% of children with cancer. This study aimed to systematically explore the burden of treatment-related mortality in children with cancer in LMICs and to explore the association between country income level and treatment-related mortality.

METHODS

For this systematic review and meta-analysis we identified articles published between Jan 1, 2010, and June 22, 2021, describing treatment-related mortality in paediatric patients (aged 0-21 years) with cancer in LMICs. We searched PubMed, Trip, Web of Science, Embase, and the WHO Global Metric Index databases. The search was limited to full-text articles and excluded case reports (<10 patients) and haematopoietic stem-cell transplantation recipients. Two reviewers independently screened studies for eligibility, extracted data from included publications, and evaluated data quality. Random and mixed-effects models were used to estimate treatment-related mortality burden and trends. The Cochran-Q statistic was used to assess heterogeneity between studies. This study is registered on PROSPERO (CRD42021264849).

FINDINGS

Of 13 269 identified abstracts, 501 studies representing 68 351 paediatric patients with cancer were included. The treatment-related mortality estimate was 6·82% (95% CI 5·99-7·64), accounting for 30·9% of overall mortality (4437 of 14 358 deaths). Treatment-related mortality was inversely related to country income. Treatment-related mortality was 14·19% (95% CI 9·65-18·73) in low-income countries, 9·21% (7·93-10·49) in lower-middle-income countries, and 4·47% (3·42-5·53) in upper-middle-income countries (Cochran-Q 42·39, p<0·0001). In upper-middle-income countries, the incidence of treatment-related mortality decreased over time (slope -0·002, p=0·0028); however, outcomes remained unchanged in low-income (p=0·21) and lower-middle-income countries (p=0·16).

INTERPRETATION

Approximately one in 15 children receiving cancer treatment in LMICs die from treatment-related complications. Although treatment-related mortality has decreased in upper-middle-income countries over time, it remains unchanged in LMICs. There is an urgent need for targeted supportive care interventions to reduce global disparities in childhood cancer survival.

FUNDING

American Lebanese Syrian Associated Charities and National Cancer Institute.

The results of the modified St Jude Total Therapy XV Protocol in the treatment of low- and middle-income children with acute lymphoblastic leukemia

The St Jude Total Therapy Study XV was the first clinical trial to prospectively use minimal residual disease levels during and after remission induction therapy to guide risk-directed treatment. We used the Total Therapy XV protocol with minimal modification in treating 115 newly diagnosed pediatric acute lymphoblastic leukemia patients from low- and middle-income groups from January 2011 to December 2017. The mean age at diagnosis was 5.97 ± 3.96 years. The median follow-up period was 88 months. Three (2.6%) patients had bone marrow relapse, and one (0.87%) had an isolated central nervous system relapse. Nineteen of the patients (16.52%) died due to infection-related complications, three (2.61%) died due to progressive disease, and one (0.87%) died due to hematopoietic stem cell transplant complications. Five-year overall survival was 80%, and event-free survival was 78.3%. Our results showed that the Total XV treatment protocol could be used successfully in patients with ALL from low- and middle-income populations. However, infection-related deaths remain a significant problem.

TPMT*3C as a Predictor of 6-Mercaptopurine-Induced Myelotoxicity in Thai Children with Acute Lymphoblastic Leukemia

The response to 6-mercaptopurine (6-MP) can be altered by genetic polymorphisms in genes encoding drug-metabolizing enzymes and drug transporters. The purpose of this study was to investigate the association between genetic polymorphisms of drug-metabolizing enzymes (TPMT 719A > G (*3C), ITPA 94C > A and ITPA 123G > A) and drug transporters (MRP4 912C > A and MRP4 2269G > A) with 6-MP-related myelotoxicity and hepatotoxicity in Thai children with acute lymphoblastic leukemia (ALL). The prescribed dosage of 6-MP and its adverse effects were assessed from medical records during the first 8 weeks and 9–24 weeks of maintenance therapy. Children with the TPMT*1/*3C genotype had a higher risk of leukopenia with an odds ratio (OR) of 4.10 (95% confidence interval (CI) of 1.06–15.94; p = 0.033) compared to wild type (TPMT*1/*1) patients. Heterozygous TPMT*3C was significantly associated with severe neutropenia with an increased risk (OR, 4.17; 95% CI, 1.25–13.90); p = 0.014) during the first 8 weeks. No association was found among ITPA94C > A, ITPA123G > A, MRP4 912C > A, and MRP4 2269G > A with myelotoxicity and hepatotoxicity. The evidence that TPMT heterozygotes confer risks of 6-MP-induced myelotoxicity also supports the convincing need to genotype this pharmacogenetic marker before the initiation of 6-MP therapy.

What are the volume and budget needs to provide chemotherapy to all children with acute lymphoblastic leukaemia in Thailand? Development and application of an estimation tool

OBJECTIVE

Insufficient access to anticancer medicines may contribute to the wide survival differences of children with cancers across the globe. We developed a tool to estimate the volume of medicines and budget requirements to provide chemotherapy to children with acute lymphoblastic leukaemia (ALL).

DESIGN

Development and application of an estimation tool.

SETTING

Paediatric oncology hospital departments in Thailand.

PARTICIPANTS

318 children aged 0-14 years diagnosed with ALL and 215 children with undiagnosed ALL.

INTERVENTIONS

Estimates of volume and budget requirements for administering a full course of chemotherapy for ALL and a further course for children who relapse, according to National Treatment Guidelines.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measures were the volume (mg) and cost (US$) of medicines needed to treat children with ALL. For medicines whose main indication is paediatric ALL (asparaginase and 6-mercaptopurine), we estimated the difference between volume needed and actual sales in 2017 (secondary outcome).

RESULTS

Ten anticancer medicines and four chemoprotective agents are needed for the treatment of paediatric ALL according to the Thai treatment guidelines. Of these 14 medicines, 13 are included in the WHO essential medicines list for children. All are available as generics. We estimated that essential chemotherapy and chemoprotective agents to treat all children diagnosed with ALL in Thailand in 2017 would cost US$ 814 952 (US$ 1 365 422 for diagnosed and undiagnosed children), which corresponds to 0.005% (0.008%) of the country's total health expenditure. The volumes of asparaginase and 6-mercaptopurine available on the Thai market in 2017 were more than sufficient (2.3 and 1.5 times the amounts needed, respectively) to treat all children diagnosed with ALL.

CONCLUSIONS

Procuring sufficient quantities of essential medicines to treat children with ALL requires relatively modest resources. Medicine cost should not be a major barrier to ALL treatment in similar settings.