Efficacy and toxicity of high-risk therapy of the Dutch Childhood Oncology Group in childhood acute lymphoblastic leukemia

Post-Induction Minimal Residual Disease in Pediatric Pre-B-Cell Acute Lymphoblastic Leukemia: A Step Towards Precision Medicine?

Background

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy with an incidence of 30% of pediatric cancers across the world and 34% amongst Saudi children with cancers. Minimal residual disease (MRD) is considered the most important independent predictor in determining the risk of relapse and long-term outcomes in ALL patients and plays a pivotal role in guiding risk-adapted therapies. The aim of this research was to study the role of MRD on survival benefits in our patient population.

Methods

We reviewed medical records of 108 pediatric (age ≤ 14 years) ALL patients treated between January 2016 and December 2018 at our center to assess if MRD and other associated risk factors affect the outcome of patients at post-induction and post-consolidation phases of the treatment protocols.

Results

The median follow-up time in our cohort of patients was 75.6 months (95% confidence interval: 71.3 - 79.8 months). With a mortality rate of 10.2% (11 deaths out of 108 cases), overall survival (OS) of the whole cohort was 89.2±3.1%. OS was significantly lower in post-induction MRD-positive cases than in MRD-negative cases (74.2±8.6% vs. 94.7±2.6%, P = 0.006). It was worse among those patients who underwent consolidation therapy and had positive post-consolidation MRD. Event-free survival (EFS) was also significantly poor in post-induction MRD-positive cases (61.1±10.2% vs. 92.1±3.1%, P = 0.001). Twenty-seven patients who received consolidation therapy had the poorest EFS (P = 0.031). Amongst all the factors, including age at diagnosis, gender, white blood cell count, central nervous system status, risk group or cytogenetics, only post-induction MRD positivity was found to be significantly associated with OS.

Conclusion

Post-induction MRD is one of the most important factors affecting the patient's outcome. Post-induction MRD-positive patients fared better after receiving consolidation therapy. No significant association was found between post-induction MRD and other risk factors.

Pro-Apoptotic Potential of Pseudevernia furfuracea (L.) Zopf Extract and Isolated Physodic Acid in Acute Lymphoblastic Leukemia Model In Vitro

Acute lymphoblastic leukemia (ALL) is the most frequently diagnosed type of leukemia among children. Although chemotherapy is a common treatment for cancer, it has a wide range of serious side effects, including myelo- and immunosuppression, hepatotoxicity and neurotoxicity. Combination therapies using natural substances are widely recommended to attenuate the adverse effects of chemotherapy. The aim of the present study was to investigate the anti-leukemic potential of extract from the lichen Pseudevernia furfuracea (L.) Zopf (PSE) and isolated physodic acid (Phy) in an in vitro ALL model. A screening assay, flow cytometry and Western blotting were used to analyze apoptosis occurrence, oxidative stress, DNA damage and stress/survival/apoptotic pathway modulation induced by the tested substances in Jurkat cells. We demonstrate for the first time that PSE and Phy treatment-induced intrinsic caspase-dependent cell death was associated with increased oxidative stress, DNA damage and cell cycle arrest with the activation of cell cycle checkpoint proteins p53, p21 and p27 and stress/survival kinases p38 MAPK, JNK and PI3K/Akt. Moreover, using peripheral T lymphocytes, we confirmed that PSE and Phy treatment caused minimal cytotoxicity in normal cells, and therefore, these naturally occurring lichen secondary metabolites could be promising substances for ALL therapy.