Population Pharmacokinetics of Cyclosporine in Chinese Pediatric Patients With Acquired Aplastic Anemia.

Cyclosporine (CsA) is a component of the first-line treatment for acquired aplastic anemia (acquired AA) in pediatric patients. This study aimed to develop a population pharmacokinetic (PK) model of CsA in Chinese pediatric patients with acquired AA to inform individual dosage regimens. A total of 681 CsA whole blood concentrations and laboratory data of 157 pediatric patients with acquired AA were retrospectively collected from two hospitals in Shanghai. A nonlinear mixed-effect model approach was used to build the population PK model. Potential covariate effects of age, body weight, and biochemical measurements (renal and liver functions) on CsA PK disposition were evaluated. Model fit was assessed using the basic goodness of fit and a visual predictive check. The CsA concentration data were accurately described using a two-compartment disposition model with first-order absorption and elimination. Body weight value was implemented as a fixed allometric function on all clearance and volume of distribution parameters. Total bilirubin level was identified as a significant covariate on apparent clearance (CL/F), with a 1.07% reduction per 1 nmol/L rise in total bilirubin level. The final estimates for CL/F and central volume (Vc/F) were 29.1 L/h and 325 L, respectively, for a typical 28 kg child. Other covariates (e.g., gender, age, albumin, hemoglobin, hematocrit, serum creatinine, and concomitant medication) did not significantly affect the PK properties of CsA. This population PK model, along with a maximum a posteriori Bayesian approach, could estimate individual PK parameters in pediatric patients with acquired AA to conduct individual CsA therapy.

Population Pharmacokinetics of High-Dose Methotrexate in Chinese Pediatric Patients With Acute Lymphoblastic Leukemia.

High-dose methotrexate (HD-MTX) is widely used in pediatric acute lymphoblastic leukemia (ALL) treatment regimens. In this study, we aimed to develop a population pharmacokinetic (PK) model of HD-MTX in Chinese pediatric patients with ALL for designing personalized dosage regimens. In total, 4,517 MTX serum concentration data for 311 pediatric patients with ALL, aged 0.75-15.2 years and under HD-MTX treatment, were retrospectively collected at a tertiary Children's Hospital in China. The non-linear mixed-effect model was used to establish the population PK model, using NONMEM software. The potential covariate effects of age, body weight, and biochemical measurements (renal and liver function) on MTX PK disposition were investigated. The model was then evaluated using goodness-of-fit, visual predictive check. MTX PK disposition was described using a three-compartment model reasonable well. Body weight, implemented as a fixed allometric function on all clearance and volume of distribution parameters, showed a substantial improvement in model fit. The final population model demonstrated that the MTX clearance estimate in a typical child with body weight of 19 kg was 6.9 L/h and the central distribution of volume estimate was 20.7 L. The serum creatinine significantly affected the MTX clearance, with a 0.97% decrease in clearance per 1 µmol/L of serum creatinine. Other covariates (e.g., age, sex, bilirubin, albumin, aspartate transaminase, concomitant medication) did not significantly affect PK properties of MTX. The proposed population PK model could describe the MTX concentration data in Chinese pediatric patients with ALL. This population PK model combined with a maximum a posteriori Bayesian approach could be used to estimate individual PK parameters, and optimize personalized MTX therapy in target patients, thus aiming to reduce toxicity and improve treatment outcomes.

Ras pathway mutation feature in the same individuals at diagnosis and relapse of childhood acute lymphoblastic leukemia.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, while relapse and refractory ALL remains a leading cause of death in children. However, paired ALL samples of initial diagnosis and relapse subjected to next-generation sequencing (NGS) could construct clonal lineage changes, and help to explore the key issues in the evolutionary process of tumor clones. Therefore, we aim to analyze gene alterations during the initial diagnosis and relapse of ALL patients and to explore the underlying mechanism. METHODS: Targeted exome sequencing technology was used to detect molecular characteristic of initial diagnosis and relapse of ALL in 12 pediatric patients. Clinical features, treatment response, prognostic factors and genetic features were analyzed. RESULTS: In our 12 paired samples, 75% of pre-B-cell acute lymphoblastic leukemia (B-ALL) patients had alterations in the Ras pathway (NRAS, KRAS, NF1, and EPOR), and Ras mutation are very common in patients with ALL relapse. TP53 mutations mainly existed in the primary clones and occurred at the initial diagnosis and relapse of ALL. Relapse-associated genes such as NT5C2 and CREBBP were observed in patients with ALL relapse; however, all patients included in this study had gene abnormalities in the Ras pathway, and NT5C2 and CREBBP genes may collaboratively promote ALL relapse. CONCLUSIONS: Among the 12 ALL patients, Ras pathway mutations are common in ALL relapse and may be associated with other recurrence-related genes alterations. The study with paired samples could improve the understanding of ALL relapse.

Genetic variants and clinical significance of pediatric acute lymphoblastic leukemia.

BACKGROUND: Acute lymphoblastic leukemia (ALL), the most common childhood malignancy, is characterized by molecular aberrations. Recently, genetic profiling has been fully investigated on ALL; however, the interaction between its genetic alterations and clinical features is still unclear. Therefore, we investigated the effects of genetic variants on ALL phenotypes and clinical outcomes. METHODS: Targeted exome sequencing technology was used to detect molecular profiling of 140 Chinese pediatric patients with ALL. Correlation of genetic features and clinical outcomes was analyzed. RESULTS: T-cell ALL (T-ALL) patients had higher initial white blood cell (WBC) count (34.8×109/L), higher incidence of mediastinal mass (26.9%), more relapse (23.1%), and enriched NOTCH1 (23.1%), FBXW7 (23.1%) and PHF6 (11.5%) mutations. Among the 18 recurrently mutated genes, SETD2 and TP53 mutations occurred more in female patients (P=0.041), NOTCH1 and SETD2 mutants were with higher initial WBC counts (≥50×109/L) (P=0.047 and P=0.041), JAK1 mutants were with higher minimal residual disease (MRD) level both on day 19 and day 46 (day 19 MRD ≥1%, P=0.039; day 46 MRD ≥0.01%, P=0.031) after induction chemotherapy. Multivariate analysis revealed that initial WBC counts (≥50×109/L), MLLr, and TP53 mutations were independent risk factors for 3-year relapse free survival (RFS) in ALL. Furthermore, TP53 mutations, age (<1 year or ≥10 years), and MLLr were independently associated with adverse outcome in B-cell ALL (B-ALL). CONCLUSIONS: MLLr and TP53 mutations are powerful predictors for adverse outcome in pediatric B-ALL and ALL. Genetic profiling can contribute to the improvement of prognostication and management in ALL patients.

Clinical outcome of childhood lymphoblastic lymphoma in Shanghai China 2001-2010.

BACKGROUND: This retrospective cohort study analysed the clinical characteristics and outcomes of patients with childhood lymphoblastic lymphoma (LBL) treated in Shanghai, China. PROCEDURE: From 2001 to 2010, 108 evaluable patients ≤16 years of age who were newly diagnosed with biopsy-proven LBL were treated with one of three treatment protocols: CCCG-99, SCMC-T-NHL-2002, or LBL-CHOF-2006. RESULTS: Two patients had Stage I disease, 5 had Stage II, 55 had Stage III, and 46 had Stage IV. The immunophenotype was T-cell LBL in 92 patients (85.2%) and precursor B-cell LBL in 16 (14.8%). The abandonment rate was 11.5%. Twenty-five patients (23.2%) suffered from resistant disease, including 1 with isolated central nervous system (CNS) relapse. At a median follow-up of 40.4 months (range, 0-114 months), the 5-year probability of event-free survival (pEFS) was 63.9 ± 4.6% in all patients. The 5-year pEFS for patients with pB-LBL was better than for patients with T-LBL (100% vs. 61.3 ± 5.1%, P = 0.007). Patients who had achieved complete remission on day 33 of induction had significantly better pEFS than those who had not (78.8 ± 4.6% vs. 28.2 ± 9.0%, P = 0.000). Three of 25 patients who experienced resistant disease were alive at the end of the study period. CONCLUSIONS: The abandonment rate was lower for patients with LBL than for patients with acute lymphoblastic leukemia. Prophylactic cranial radiation can be omitted for patients with LBL even when advanced-stage disease is present, as intensive systemic chemotherapy with intrathecal therapy is sufficient to prevent CNS relapse. The survival of patients with resistant disease was very poor.

[Comparison of the efficacy of CCCG-97 and BFM-90 protocols in the treatment for children with mature B-cell non-Hodgkin's lymphoma].

OBJECTIVE: The aim of this study was to evaluate the efficacy and toxicity of the CCCG-97 and BFM-90 protocols in the treatment of pediatric patients with B-cell non-Hodgkin's lymphoma (B-NHL) retrospectively, and to explore the optimal therapeutic strategy. METHODS: Forty-five consecutive untreated patients (age of 18 years or less) with newly diagnosed B-NHL (including Burkitt Lymphoma and diffuse large B-cell lymphoma), treated in our hospital between July 1999 and December 2008 were enrolled in this study. The patients were classified into 2 groups by different protocols. From July 1999 to December 2004, twenty-one 3- to 13.8-year-old children were enrolled in the CCCG-97 group, with 1 in stage I/II, and 20 in stage III/IV(St Jude staging). From January 2005 to December 2008, twenty-four 2.8- to 14.1-year-old cases were enrolled in the BFM-90 group, with 3 in stage I/II, and 21 in stage III/IV (St Jude staging). The survival rates were evaluated by Kaplan-Meier analysis. RESULTS: Forty of the 45 patients (88.9%) reached complete response (CR) after 2 courses of chemotherapy. In the CCCG-97 group, the CR rate was 95.2% (20/21 pts), while that in the BFM-90 group was 83.3% (20/24 pts). At a median follow-up time of 62 (17 to 131) months, the 5-year event-free survival (EFS) was 71.8% for all patients, and 69.1% for Stage III/IV, respectively. In the CCCG-97 group, the 3-year EFS was 76.2%. In the BFM-90 group, it was 75.0%. There was no significant difference in survival rates between the CCCG-97 and BFM-90 groups (P=0.975). Unfavorable events recorded were as follows: Death of progression before achieving CR during induction therapy in 4 cases, and relapse after achieving CR in 6 cases. The relapse rates were 19.0% (4/21 pts) in the CCCG-97 group and 8.3% (2/24 pts) in the BFM-90 group, with a non-significant statistical difference (P=0.292). Major toxicities were myelosuppression and mucositis, especially in the BFM-90 group, but were tolerable and manageable. five patients in the BFM-90 group received rituximab, 2 patients (Stage III) achieved CR, while the other 3 patients (Stage IV) had progressive disease or relapse. CONCLUSIONS: Short-pulse and intensive chemotherapy, stratified according to stage of disease, can improve the survival rate of pediatric mature B-NHL. The efficacy of the CCCG-97 protocol and BFM-90 protocol is comparable and the toxicity is tolerable.