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.

Outcomes with reduced intensity therapy in a low-risk subset of children with National Cancer Institute (NCI) standard-risk (SR) B-lymphoblastic leukemia (B-ALL): A report from Children’s Oncology Group (COG) AALL0932

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Background: Post-hoc analysis of COG P9904 identified a low risk (LR) group of SR B-ALL patients aged 1-9.99 years with WBC < 50,000/µL, no CNS3, and either ETV6/RUNX1 or double trisomies (DT) of chromosomes 4 and 10 with day 8 peripheral blood (PB) and day 29 marrow (BM) minimal residual disease (MRD) < 0.01% who had a 5-year event-free survival (EFS) of 97±2% and overall survival (OS) 98.8±0.8%. Outstanding results were also obtained for LR patients on COG AALL0331 using CCG-based ALL therapy. AALL0932 tested prospectively whether LR B-ALL patients could attain a 5-year EFS ≥95% with these regimens. Methods: Following a 3-drug induction, eligible AALL0932 LR patients had NCI SR B-ALL (no testicular leukemia, unfavorable genetics or Down syndrome) with DT or ETV6/RUNX1 fusion, CNS1, no steroid pre-treatment, with Day 8 PB and Day 29 BM MRD < 0.01%. Between 2010-16, 603 LR patients were randomized to P9904-based regimen LR-M (n = 301) or CCG 1991/COG AALL0331-based regimen LR-C (n = 302). LR-M included 6 24-hour infusions of 1 gm/m2 of methotrexate (MTX) with leucovorin rescue, but no anthracyclines or alkylating agents. Maintenance followed with daily 6-mercaptopurine (6-MP) and weekly oral MTX, and every 16 week 7-day pulses of dexamethasone (DEX) with vincristine (VCR) on days 1 and 8. Boys and girls were treated for 2.5 years from diagnosis. LR-C had no 24-hour MTX infusions, but included 2 Interim Maintenance (IM) phases with VCR and escalating IV MTX without leucovorin rescue given every 10 days for 5 doses, flanking an 8-week Delayed Intensification (DI) phase that included DEX, VCR, pegasparagase, doxorubicin (75 mg/m2), cyclophosphamide (1 gm/m2) and 8 doses of low-dose cytarabine (75 mg/m2/dose). LR-C Maintenance included daily 6-MP and weekly oral MTX with 5-day pulses of DEX and 1 dose of VCR given every 12 weeks. Girls received 2 years and boys 3 years of therapy from the start of IM I. Results: Both regimens achieved outstanding outcomes: 5-yr disease-free survival (±SE) 98.8%±0.8% for LR-M and 98.5%±0.9% for LR-C (p = 0.67). Both had 5-yr OS 100%. Therapies were well tolerated with higher rates of mucositis (12.9 vs 6.3%; p = 0.008) and allergic reactions (2.3% vs 0%; p = 0.02) on LR-C. Conclusions: AALL0932 demonstrated that application of stringent risk criteria can identify a favorable B-ALL subgroup almost certain to be cured with either LR-M or LR-C, allowing physicians and families to select the optimal treatment approach in the future. Clinical trial information: NCT01190930.

The effect of estrogen on muscle damage biomarkers following prolonged aerobic exercise in eumenorrheic women

This study assessed the influence of estrogen (E₂) on muscle damage biomarkers [skeletal muscle - creatine kinase (CK); cardiac muscle - CK-MB] responses to prolonged aerobic exercise. Eumenorrheic women (n=10) who were physically active completed two 60-minute treadmill running sessions at ∼60-65% maximal intensity during low E₂ (midfollicular menstrual phase) and high E₂ (midluteal menstrual phase) hormonal conditions. Blood samples were collected prior to exercise (following supine rest), immediately post-, 30 min post-, and 24 hours post-exercise to determine changes in muscle biomarkers. Resting blood samples confirmed appropriate E₂ hormonal levels Total CK concentrations increased following exercise and at 24 hours post-exercise were higher in the midfollicular low E₂ phase (p<0.001). However, CK-MB concentrations were unaffected by E₂ level or exercise (p=0.442) resulting in the ratio of CK-MB to total CK being consistently low in subject responses (i.e., indicative of skeletal muscle damage). Elevated E₂ levels reduce the CK responses of skeletal muscle, but had no effect on CK-MB responses following prolonged aerobic exercise. These findings support earlier work showing elevated E₂ is protective of skeletal muscle from exercise-induced damage associated with prolonged aerobic exercise.

Pharmacokinetic and pharmacodynamic properties of calaspargase pegol Escherichia coli L-asparaginase in the treatment of patients with acute lymphoblastic leukemia: results from Children's Oncology Group Study AALL07P4

PURPOSE

Asparaginase is a critical agent used to treat acute lymphoblastic leukemia (ALL). Pegaspargase (SS-PEG), a pegylated form of Escherichia coli L-asparaginase with a succinimidyl succinate (SS) linker, is the first-line asparaginase product used in Children's Oncology Group (COG) ALL trials. Calaspargase pegol (SC-PEG) replaces the SS linker in SS-PEG with a succinimidyl carbamate linker, creating a more stable molecule. COG AALL07P4 was designed to determine the pharmacokinetic and pharmacodynamic comparability of SC-PEG to SS-PEG in patients with newly diagnosed high-risk (HR) B-cell ALL.

PATIENTS AND METHODS

A total of 165 evaluable patients were randomly assigned at a 2:1 ratio to receive SC-PEG at 2,100 (SC-PEG2100; n = 69) or 2,500 IU/m(2) (SC-PEG2500; n = 42) versus SS-PEG 2,500 IU/m(2) (SS-PEG2500; n = 54) as part of an otherwise identical chemotherapy regimen. The groups were similar demographically, except more female patients received SC-PEG2500.

RESULTS

The mean half-life of plasma asparaginase activity for both SC-PEG doses was approximately 2.5× longer than that of SS-PEG2500. The total systemic exposure, as defined by induction area under the curve from time 0 to 25 days, was greater with SC-PEG2500 than with SS-PEG2500 or SC-PEG2100. The proportion of patients with plasma asparaginase activity ≥ 100 mIU/mL and ≥ 400 mIU/mL was higher in patients who received SC-PEG as compared with SS-PEG2500. After one dose of pegylated asparaginase on induction day 4, plasma asparagine was undetectable for 11 days for SS-PEG2500 and 18 days for both SC-PEG groups.

CONCLUSION

SC-PEG2500 achieves a significantly longer period of asparaginase activity above defined thresholds and asparagine depletion compared with SS-PEG2500 and has a comparable toxicity profile in children with HR B-cell ALL.

Pharmacokinetic (PK) and pharmacodynamics (PD) properties of SC-PEG e. coli L-asparaginase (EZN-2285) in the treatment of patients with acute lymphoblastic leukemia (ALL): Results from Children's Oncology Group (COG) study AALL07P4

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Background: Asparaginase is a critical therapeutic agent in the treatment of childhood ALL, and pegaspargase (Oncospar, ONC) is now the preferred product in COG frontline ALL trials. EZN-2285 replaces the succinimidyl succinate linker in ONC with a succinimidyl carbamate linker creating a more stable molecule. AALL07P4 was designed to determine the PK comparability of EZN-2285 to ONC when given intravenously in newly diagnosed patients with NCI high-risk (HR) B-precursor ALL. Methods: 162 eligible patients were randomized to receive EZN-2285 at 2100 (LD, n=66) or 2500 (HD, n=42) IU/m2 vs. 2500 IU/m2 of ONC (n=51) in a 2:1 manner based on the prednisone/Capizzi methotrexate arm of COG AALL0232. All groups were similar demographically with the exception of number of patients over the age of 16 years were 6, 5, and 19 in the ONC, HD and LD, respectively. Results: PK, PD and targeted AEs (Gr 3-5) after the first doses of study drug are presented in the table below. Adverse events in induction were not significantly different between arms with the exception of a higher incidence of hyperglycemia (p=0.042). Conclusions: Based on Cmax , AUC0-25d , and asparaginase activity 25 days post drug, EZN-2285 2500 IU/m2 appears to have an improved PK/PD profile compared to pegaspargase 2500 IU/m2 and a comparable toxicity profile in children with HR ALL. [Table: see text]