Precision-guided treatment boosts outcomes in children with high-risk cancers

A recent Nature Medicine study investigates the effectiveness of precision-guided treatment (PGT) in children at a high risk of cancer.

Study: Precision-guided treatment in high-risk pediatric cancers. Image Credit: S_L / Shutterstock.com

Barriers to precision medicine implementation

The combination of next-generation sequencing (NGS) and targeted anti-cancer therapies has advanced precision medicine for the treatment of cancer.

Although pediatric precision oncology-based research has successfully identified molecular targets in over 65% of children with high cancer risks, the clinical application of this strategy is significantly low. This low clinical uptake of precision medicine could be attributed to physician uncertainty towards the efficacy and benefit-risk balance of PGT.

Previous studies have highlighted the clinical benefits of PGT. However, there remains a lack of data on these treatments’ objective response or survival outcomes, thus necessitating additional data to determine when and which patients should receive PGT.

About the study

The Australian ZERO Childhood Cancer Precision Medicine Program conducted a multicenter cohort-based clinical trial. Study participants were recruited between September 2017 and December 2020 from eight pediatric oncology centers in Australia, with prospective data collected between September 2017 and June 2022.

The current study aimed to determine the proportion of pediatric cancer patients to be recommended to physicians for PGT in a clinically relevant time frame. Subsequently, the treatment response and survival rate of patients receiving PGT, as compared to those who were not prescribed PGT, were also assessed.

Study participants of any gender who were younger than 21 years of age with a suspected or confirmed high-risk malignancy were recruited. The possibility of a cure for these patients was lower than 30%.

Patient tumor and germline samples were collected from the test centers. DNA was extracted from the samples, and whole genome sequencing (WGS) of paired tumor-germline was performed. DNA methylation analysis was also conducted on all tumor samples.

Study findings

In the current study, 50-60 individuals, including clinicians, subject matter experts, and scientists, attended weekly molecular tumor board (MTB) presentations. Every patient included in this study was discussed for 10-15 minutes during these meetings.

A total of 384 patients were included in the current study, 67% of whom were recommended to receive PGT, whereas the remaining 29% were included in the non-PGT cohort. Of the 256 patients who were advised to receive PGT, 110 were ultimately treated with PGT, which reflects the highest uptake rate of PGT recorded in pediatric oncology studies.

PGT was associated with a 36% objective response rate and a 26% two-year progression-free survival rate, compared to 12% and 5.2% of patients receiving standard care or targeted agents, respectively. The three-year overall survival (OS) of the PGT cohort was estimated to be 34%.

These improvements have been attributed to targeting fusions and early treatment for children with a higher risk of malignancy. Selection of new anti-cancer agents based on the genomic profile also contributed to improved survival rates.

The current study demonstrated the clinical benefits of PGT compared to non-PGT, unguided therapy (UGT), or standard of care (SOC) treatment using the intra-patient progression-free survival (PFS) ratio as an outcome measure in pediatric precision medicine. Compared to PGT, UGT resulted in a significantly inferior outcome, which emphasizes the importance of molecular evidence-guided therapeutic decision-making in pediatric cohorts.

Although the clinical benefits of PGT compared to non-PGT on PFS were established, the current study failed to demonstrate the impact of PGT on OS. In this context, no significant difference in two-year OS among PGT, non-PGT, UGT, and SOC was observed, which could be due to patients being treated with several different types of therapies. Thus, a more extended follow-up study is needed to elucidate the impact on OS.

PGT informed by comprehensive molecular profiling significantly improves outcomes for children with high-risk cancers.”

Conclusions

The current study reports the significant benefits of PGT compared to UGT and non-PGT in terms of response rate and two-year PFS. These findings demonstrate the importance of identifying tumor biomarkers and integrating precision medicine into SOC for pediatric patients. Nevertheless, the current study has some limitations, including its nonrandomized design and relatively small numbers of patients in the subgroup analysis.

In the future, more biomarker-driven interventions must be formulated to improve treatment outcomes in pediatric patients with an increased cancer risk. The effectiveness of combination therapies and the timing of PGT must also be optimized.