Phase 2 trial of clofarabine in combination with etoposide and cyclophosphamide in pediatric patients with refractory or relapsed acute lymphoblastic leukemia

Old drug, new use: Recent advances for G-CSF

Granulocyte colony-stimulating factor (G-CSF), also known as colony-stimulating factor 3 (CSF3), is a proinflammatory cytokine that primarily stimulates the survival, proliferation, differentiation and function of neutrophil granulocyte progenitor cells and mature neutrophils. Over the past years, G-CSF has mainly been used to cure patients with neutropenia and as a part of chemotherapy to induct the remission for refractory/relapse leukemia. Recent studies showed that C-CSF can been used as condition regimens and as a part of preventive methods after allogeneic transplantation to improve the survival of patients and also has immunoregulation, and has promote or inhibit the proliferation of solid tumors. Therefore, in this review, we firstly describe the structure for G-CSF. Then its functions and mechanism were reviewed including the neutrophil mobilization, differentiation, migration, and inhibiting apoptosis of neutrophils, and its immunoregulation. Finally, the clinical applications were further discussed.

Treatment of relapsed acute lymphoblastic leukemia in children: an observational study of the Japan Children's Cancer Group

The Japan Children's Cancer Group Relapsed Acute Lymphoblastic Leukemia (ALL) Committee conducted a prospective observational study (ALL-R14) to explore promising reinduction therapy regimens for relapsed ALL to investigate in future trials. In Japan, clofarabine- and bortezomib-based regimens were of interest since they were newly introduced for ALL in the study period (2015-2018). Seventy-five pediatric patients were enrolled in total. The 2-year event-free/overall survival rates in patients with first (n = 59) or second (n = 11) relapse were 40.1% (95% confidence interval [CI]: 25.5-52.3%)/66.3% (95% CI 52.3-77.0%) and 34.1% (95% CI 9.1-61.6%)/62.3% (95% CI 27.7-84.0%), respectively. Clofarabine- or bortezomib-based regimens were used only in patients with high-risk disease. The first reinduction therapy used in the 41 patients with early or multiple relapsed B-cell precursor ALL was clofarabine in 7 patients and bortezomib in 9 patients. The odds ratio for reinduction failure risk with a clofarabine- or bortezomib-based regimen compared with other regimens was 9.0 (95% CI 0.9-86.4, P = 0.057) or 1.9 (95% CI 0.4-8.7, P = 0.42), respectively. Thus, clofarabine- or bortezomib-based regimens had no obvious advantage as reinduction therapy for relapsed ALL in children.

Daratumumab and venetoclax combined with CAGE for late R/R T-ALL/LBL patients: Single-arm, open-label, phase I study

The prognosis of patients diagnosed with relapsed or refractory (R/R) T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) has consistently been unsatisfactory, with limited treatment options. As reports, the CAG regimen can serve as a salvage treatment for R/R T-ALL/LBL, but there remains a subset of patients who do not benefit from it. Recent studies have indicated that daratumumab (Dara) and venetoclax (Ven) may offer promising therapeutic benefits for T-ALL/LBL. In light of these findings, we conducted a safety and efficacy evaluation of the enhanced treatment regimen, combining Dara and Ven with aclarubicin, cytarabine, granulocyte colony-stimulating factor, and etoposide (CAGE), in patients suffering from R/R T-ALL/LBL. The participants in this phase I trial were patients with R/R T-ALL/LBL who fail to standard treatment regimens. During each 28-day cycle, the patients were treated by Dara, Ven, cytarabine, aclarubicin, granulocyte colony-stimulating factor, etoposide. The primary endpoint of this study was the rate of remission. This report presents the prospective outcomes of 21 patients who received the salvage therapy of Dara and Ven combined with the CAGE regimen (Dara + Ven + CAGE). The objective remission rate (ORR) was determined to be 57.1%, while the complete remission (CR) rate was 47.6%. Notably, patients with the early T-cell precursor (ETP) subtype exhibited a significantly higher remission rate in the bone marrow compared to non-ETP patients (100% vs. 44.4%, p = 0.044). The Dara + Ven + CAGE regimen demonstrated a favorable remission rate in patients with R/R T-ALL/LBL. Moreover, the treatment was well-tolerated.

Safety and effectiveness of clofarabine in Japanese patients with relapsed/refractory acute lymphoblastic leukaemia: a post-marketing surveillance study

OBJECTIVE

Clofarabine is used to treat acute lymphoblastic leukaemia, but evidence of its safety and effectiveness in Japanese patients is limited. We evaluated the safety and effectiveness of clofarabine in patients with relapsed/refractory acute lymphoblastic leukaemia in real-world clinical practice in Japan.

METHODS

An observational, multicenter, post-marketing, all-case surveillance was conducted for safety. Effectiveness analyses were conducted in patients aged ≤21 years and those treated with clofarabine monotherapy and combination therapy (clofarabine plus etoposide and cyclophosphamide).

RESULTS

In the all-case survey, 260 of 264 registered patients were eligible for safety analysis. Among the 225 patients eligible for effectiveness analysis, 139 were aged ≤21 years. For monotherapy and combination therapy, 20/31 and 34/88 patients were eligible, respectively. In the all-case survey, the median age was 16.0 years, and 47.7% of patients were <15 years old. Adverse drug reaction incidence was 83.5% and the most common were hematologic toxicities. The best overall response rates in the population aged ≤21 years were complete remission, 29.7%; complete remission without platelet recovery, 7.3% and partial remission, 10.9%. The rest (52.2%) were classified as ineffective. The sum of complete remission, complete remission without platelet recovery and partial remission rates (effectiveness rate) was 47.8% (66/138 patients). The effectiveness rates in the monotherapy and combination therapy surveys were 10.0% (2/20 patients) and 58.8% (20/34 patients), respectively.

CONCLUSIONS

These post-marketing surveys provide real-world evidence of the safety and effectiveness of clofarabine regimens, including monotherapy and combination therapy in Japanese patients with relapsed/refractory acute lymphoblastic leukaemia. The safety and effectiveness profiles were comparable with those of previous prospective studies.

Relapsed Acute Lymphoblastic Leukemia

Outcomes for children with acute lymphoblastic leukemia (ALL) have improved worldwide to >85%. For those who relapse, outcomes have remained static at ~50% making relapsed acute lymphoblastic leukemia one of the leading causes of death in childhood cancers. Those relapsing within 18 mo in the bone marrow have a particularly dismal outcome. The mainstay of treatment is chemotherapy, local radiotherapy with or without hematopoietic stem cell transplantation (HSCT). Improved biological understanding of mechanisms of relapse and drug resistance, use of innovative strategies to identify the most effective and least toxic treatment regimens and global partnerships are needed to improve outcomes in these patients. Over the last decade, new therapeutic options and strategies have been developed for relapsed ALL including immunotherapies and cellular therapies. It is imperative to understand how and when to use these newer approaches in relapsed ALL. Increasingly, integrated precision oncology strategies are being used to individualize treatment of patients with relapsed ALL, especially in patients with poor response disease.

Patient-Level Meta-analysis of Clofarabine in Acute Lymphoblastic Leukemia

INTRODUCTION

Clofarabine monotherapy at a dose of 52 mg/m2 per day was approved in the USA in 2004 for the treatment of relapsed or refractory acute lymphoblastic leukemia (R/R ALL) in patients aged 1-21 years after at least two prior regimens. To address a post-marketing requirement for additional evidence of the clinical benefit of clofarabine in its approved indication, a meta-analysis of patient-level data was conducted.

METHODS

A systematic literature review was conducted, using the Dr.Evidence software platform, DOC Search, and Embase, to identify clinical trials with patients with R/R ALL who received clofarabine monotherapy at 52 mg/m2. The primary endpoint was complete remission (CR). Secondary endpoints were overall remission (OR, defined by CR or CR with either incomplete platelet recovery or incomplete neutrophil and platelet recovery), duration of response, overall survival (OS), and safety.

RESULTS

A total of 754 patients in 12 clinical studies were analyzed including 682 patients with R/R ALL treated with clofarabine monotherapy at 52 mg/m2; of them, 374 were aged < 22 years (pediatric population). Rates of CR and OR were 16% (95% confidence interval [CI] 7, 26) and 28% (95% CI 20, 37), respectively, in the pediatric population and 12% (95% CI 5, 21) and 21% (95% CI 13, 31) in the overall population. Median OS (evaluable in three studies in pediatric patients) was 3.7 months (95% CI 0.1, 31.4), reaching 10.1 months (95% CI 0.3, 68.9) for those achieving OR. Sensitivity analyses supported these findings. The most frequent grade 3-4 adverse events were liver abnormalities, anemia, diarrhea, and febrile neutropenia.

CONCLUSION

In this meta-analysis, CR duration and median OS in pediatric patients with R/R ALL appeared to be slightly longer than in the phase II study. No new safety signals were identified. Results support the use of clofarabine monotherapy in its approved indication.

Clofarabine in Pediatric Acute Relapsed or Refractory Leukemia: Where Do We Stand on the Bridge to Hematopoietic Stem Cell Transplantation?

BACKGROUND

Despite pronounced improvement in overall survival (OS) in pediatric leukemia, a proportion of patients continue to suffer from lack of response or relapse, and the management of such patients is exceedingly difficult. Immunotherapy and engineered chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the course of relapsed or refractory acute lymphoblastic leukemia (ALL). However, conventional chemotherapy continues to be utilized for re-induction purposes whether independently or in combination with immunotherapy.

METHODS

Forty-three pediatric leukemia patients (age < 14 years at diagnosis) consecutively diagnosed at our institution and got treated with clofarabine based regimen at a single tertiary care hospital between January 2005 and December 2019 were enrolled in this study. ALL comprised of 30 (69.8%) patients of the cohort while the remaining 13 (30.2%) were with acute myeloid leukemia (AML).

RESULTS

Post-clofarabine bone marrow (BM) was negative in 18 (45.0%) cases. Overall clofarabine failure rate was 58.1% (n = 25) with 60.0% (n = 18) in ALL and 53.8% (n = 7) in AML (P = 0.747). Eighteen (41.9%) patients eventually underwent hematopoietic stem cell transplantation (HSCT); 11 (61.1%) were from ALL group and remaining seven (38.9%) were AML (P = 0.332). Three- and 5-year OS of our patients was 37.7±7.6% and 32.7±7.3%. There was a trend of better OS for ALL patients compared to AML (40.9±9.3% vs. 15.4±10.0%, P = 0.492). Cumulative probability of 5-year OS was significantly better in transplanted patients (48.1±12.1% vs. 21.4±8.4%, P = 0.024).

CONCLUSIONS

Though almost 90% of our patients proceeded to HSCT with complete response post-clofarabine treatment, yet clofarabine-based regimens are associated with the significant burden of infectious complications and sepsis-related deaths.

Quantification of clofarabine in urine and plasma by LC-MS/MS: suitable for PK study and TDM in pediatric patients with relapsed or refractory ALL

Clofarabine is approved for the treatment of relapsed or refractory acute lymphoblastic leukemia (ALL) in pediatric patients aged 1 to 21 years. Its pharmacokinetic (PK) exposure is strongly related to clinical outcomes and high risk of adverse reactions. PK-guided dosing of nucleoside analogs has the potential to improve survival and reduce toxicity in children. Considering that blood collection is an invasive operation and that the volume of blood collected is usually limited in pediatric ALL patients, a convenient and efficient method for the quantification of clofarabine in human urine and plasma was established with an LC-MS/MS system. Standard curves were shown to be liner in the range of 2.00-1000.00 ng mL-1 in both urine and plasma. Analytical validation of the assay included the assessment of linearity, accuracy (RE: -6.62% to 2.32%), intra-assay precision (RSD: 0.81% to 3.87%) and inter-assay precision (RSD: 1.88% to 5.69%). The absolute recovery rates of clofarabine were 85.50 ± 4.80%, 89.40 ± 0.70% and 98.00 ± 0.40% in urine and were 80.76 ± 1.88%, 86.81 ± 0.75%, 88.10 ± 0.61% in plasma at 5.00, 30.00 and 800.00 ng mL-1, respectively. The selectivity, stability and matrix effects conformed to the biological sample analysis requirements. The cumulative urine excretion rates for 24 hours of the three children with relapsed and refractory acute lymphoblastic leukemia were 72.22%, 87.88%, 82.16%, respectively. The PK data of the pediatric patient numbered lflb13-05 are very inconsistent with that of the other two children subjects, demonstrating that there may be an individual variation in Chinese pediatric patients, so the dose should be individualized based on the monitoring of drug concentration. The method is convenient, sensitive, and accurate, and it is suitable for the determination of clofarabine urine and plasma concentration. This is the first report on the pharmacokinetics of clofarabine in Chinese ALL children. Furthermore, it could be an alternative method to clinical monitoring of clofarabine.

Nelarabine, etoposide, and cyclophosphamide in relapsed pediatric T-acute lymphoblastic leukemia and T-lymphoblastic lymphoma (study T2008-002 NECTAR)

Children with relapse of T-cell acute lymphoblastic leukemia (T-ALL) or lymphoblastic lymphoma (T-LBL) have a dismal prognosis, largely due to difficulty attaining second remission. We hypothesized that adding etoposide and cyclophosphamide to the nucleoside analog nelarabine could improve response rates over single-agent nelarabine for relapsed T-ALL and T-LBL. This phase I dose-escalation trial's primary objective was to evaluate the dose and safety of nelarabine given in combination with etoposide at 100 mg/m² /day and cyclophosphamide at 330-400 mg/m² /day, each for 5 consecutive days in children with either T-ALL (13 patients) or T-LBL (10 patients). Twenty-three patients were treated at three dose levels; 21 were evaluable for dose-limiting toxicities (DLT) and response. The recommended phase II doses (RP2D) for this regimen, when given daily ×5 every 3 weeks, were nelarabine 650 mg/m² /day, etoposide 100 mg/m² /day, and cyclophosphamide 400 mg/m² /day. DLTs included peripheral motor and sensory neuropathies. An expansion cohort to evaluate responses at the RP2D was terminated early due to slow accrual. The overall best response rate was 38% (8/21), with 33% (4/12) responses in the T-ALL cohort and 44% (4/9) responses in the T-LBL cohort. These response rates are comparable to those seen with single-agent nelarabine in this setting. These data suggest that the addition of cyclophosphamide and etoposide to nelarabine does not increase the incidence of neurologic toxicities or the response rate beyond that obtained with single-agent nelarabine in children with first relapse of T-ALL and T-LBL.

A phase I study of inotuzumab ozogamicin as a single agent in pediatric patients in Japan with relapsed/refractory CD22-positive acute lymphoblastic leukemia (INO-Ped-ALL-1)

Inotuzumab ozogamicin (InO) is a CD22-directed antibody conjugated with calicheamicin approved for adult relapsed or refractory CD22-positive acute lymphoblastic leukemia (ALL). This phase 1 study primarily aimed to determine the pediatric recommended doses of InO through the standard 3 + 3 design, and to evaluate the safety, tolerability, pharmacokinetic (PK) profile, immunogenicity and efficacy of InO. Dose level 1 (DL1) was 1.8 mg/m² (days 1, 8, and 15: 0.8, 0.5, and 0.5 mg/m², respectively). Six of the seven registered patients were eligible [median age, 7.5 (2-17) years]. Although all six patients started DL1, only five completed the dose. No dose-limiting toxicity was observed. All patients experienced adverse events (AEs), including increased alanine aminotransferase and aspartate aminotransferase in four patients. Three patients experienced serious AEs, which were hepatic veno-occlusive disease (VOD), ALL, and fever. Five patients achieved complete remission (CR) or CR with incomplete blood cell recovery (CRi), among whom 3 (60%) were negative for minimal residual disease. PK findings were similar to those in adults. No patient had anti-drug antibodies to InO. In conclusion, InO was well tolerated in children and promoted similar antileukemic efficacy as in adults. Nonetheless, the risk for VOD requires attention.

Role of Drug Transporters in Elucidating Inter-Individual Variability in Pediatric Chemotherapy-Related Toxicities and Response

Pediatric cancer treatment has evolved significantly in recent decades. The implementation of risk stratification strategies and the selection of evidence-based chemotherapy combinations have improved survival outcomes. However, there is large interindividual variability in terms of chemotherapy-related toxicities and, sometimes, the response among this population. This variability is partly attributed to the functional variability of drug-metabolizing enzymes (DME) and drug transporters (DTS) involved in the process of absorption, distribution, metabolism and excretion (ADME). The DTS, being ubiquitous, affects drug disposition across membranes and has relevance in determining chemotherapy response in pediatric cancer patients. Among the factors affecting DTS function, ontogeny or maturation is important in the pediatric population. In this narrative review, we describe the role of drug uptake/efflux transporters in defining pediatric chemotherapy-treatment-related toxicities and responses. Developmental differences in DTS and the consequent implications are also briefly discussed for the most commonly used chemotherapeutic drugs in the pediatric population.

Transcriptional Regulation of Yin-Yang 1 Expression through the Hypoxia Inducible Factor-1 in Pediatric Acute Lymphoblastic Leukemia

Yin-Yang transcription factor 1 (YY1) is involved in tumor progression, metastasis and has been shown to be elevated in different cancers, including leukemia. The regulatory mechanism underlying YY1 expression in leukemia is still not understood. Bioinformatics analysis reveal three Hypoxia-inducible factor 1-alpha (HIF-1α) putative binding sites in the YY1 promoter region. The regulation of YY1 by HIF-1α in leukemia was analyzed. Mutation of the putative YY1 binding sites in a reporter system containing the HIF-1α promoter region and CHIP analysis confirmed that these sites are important for YY1 regulation. Leukemia cell lines showed that both proteins HIF-1α and YY1 are co-expressed under hypoxia. In addition, the expression of mRNA of YY1 was increased after 3 h of hypoxia conditions and affect several target genes expression. In contrast, chemical inhibition of HIF-1α induces downregulation of YY1 and sensitizes cells to chemotherapeutic drugs. The clinical implications of HIF-1α in the regulation of YY1 were investigated by evaluation of expression of HIF-1α and YY1 in 108 peripheral blood samples and by RT-PCR in 46 bone marrow samples of patients with pediatric acute lymphoblastic leukemia (ALL). We found that the expression of HIF-1α positively correlates with YY1 expression in those patients. This is consistent with bioinformatic analyses of several databases. Our findings demonstrate for the first time that YY1 can be transcriptionally regulated by HIF-1α, and a correlation between HIF-1α expression and YY1 was found in ALL clinical samples. Hence, HIF-1α and YY1 may be possible therapeutic target and/or biomarkers of ALL.

Novel Treatments for Pediatric Relapsed or Refractory Acute B-Cell Lineage Lymphoblastic Leukemia: Precision Medicine Era

With the markedly increased cure rate for children with newly diagnosed pediatric B-cell acute lymphoblastic leukemia (B-ALL), relapse and refractory B-ALL (R/R B-ALL) remain the primary cause of death worldwide due to the limitations of multidrug chemotherapy. As we now have a more profound understanding of R/R ALL, including the mechanism of recurrence and drug resistance, prognostic indicators, genotypic changes and so on, we can use newly emerging technologies to identify operational molecular targets and find sensitive drugs for individualized treatment. In addition, more promising and innovative immunotherapies and molecular targeted drugs that are expected to kill leukemic cells more effectively while maintaining low toxicity to achieve minimal residual disease (MRD) negativity and better bridge hematopoietic stem cell transplantation (HSCT) have also been widely developed. To date, the prognosis of pediatric patients with R/R B-ALL has been enhanced markedly thanks to the development of novel drugs. This article reviews the new advancements of several promising strategies for pediatric R/R B-ALL.

A Systematic Review of Health Technology Assessments of Chimeric Antigen Receptor T-Cell Therapies in Young Compared With Older Patients

OBJECTIVES

The objective of this review was to identify sources of variability in cost-effectiveness analyses of chimeric antigen receptor T-cell (CAR-T) therapies, tisagenlecleucel and axicabtagene ciloleucel, evaluated by health technology assessment (HTA) agencies, focusing on young compared with older patients.

METHODS

HTA evaluations in pediatric acute lymphoblastic leukemia (ALL) and adult diffuse large B-cell lymphoma (DLBCL) were included from Australia, Canada, England, Norway, and the United States. Key clinical evidence, economic approach, and outcomes (costs, quality-adjusted life-years [QALYs] and incremental cost-effectiveness ratios) were summarized.

RESULTS

Fourteen HTA evaluations were identified (5 ALL, 9 DLBCL [4 tisagenlecleucel, 5 axicabtagene]). Analyses were naive comparisons of prospective single-arm studies for the CAR-Ts with retrospective cohort studies for the comparators. Key clinical evidence and economic model approaches were generally consistent by CAR-T and indication, although outcomes varied. Notably, incremental QALYs varied substantially in ALL (3.67-10.6 QALYs gained), whereas variation in DLBCL was less (1.21-1.97 [tisagenlecleucel], 1.97-3.40 [axicabtagene]). Discounting of costs and outcomes varied, with the highest QALYs generated for tisagenlecleucel in ALL (10.95) associated with the lowest discount rate (1.5%) and vice versa (4.97 QALYs; 5% discount rate). The approach to extrapolation of overall survival data varied, even where the same empirical data were used.

CONCLUSION

Modeled, long-term treatment benefit in young patients may be associated with greater uncertainty compared with adults because of potential life-long benefits with cell and gene therapies. This reflects the methodological challenges identified by HTA agencies associated with single-arm, short-term studies.

A novel strategy for combination of clofarabine and pictilisib is synergistic in gastric cancer

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Drug sensitivity testing identified novel drugs like clofarabine effective in treating gastric cancer.

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mRNA sequencing can be used to identify agents with synergistic activity to a reference compound.

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Pictilisib sensitizes gastric cancer to clofarabine treatment through AKT inhibition.

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The combination of clofarabine and pictilisib inhibits tumor growth in cell lines and PDX models.

Gastric cancer (GC) is frequently characterized by resistance to standard chemotherapeutic regimens and poor clinical outcomes. We aimed to identify a novel therapeutic approach using drug sensitivity testing (DST) and our computational SynerySeq pipeline. DST of GC cell lines was performed with a library of 215 Federal Drug Administration (FDA) approved compounds and identified clofarabine as a potential therapeutic agent. RNA-sequencing (RNAseq) of clofarabine treated GC cells was analyzed according to our SynergySeq pipeline and identified pictilisib as a potential synergistic agent. Clonogenic survival and Annexin V assays demonstrated increased cell death with clofarabine and pictilisib combination treatment (P<0.01). The combination induced double strand breaks (DSB) as indicated by phosphorylated H2A histone family member X (γH2AX) immunofluorescence and western blot analysis (P<0.01). Pictilisib treatment inhibited the protein kinase B (AKT) cell survival pathway and promoted a pro-apoptotic phenotype as evidenced by quantitative real time polymerase chain reaction (qRT-PCR) analysis of the B-cell lymphoma 2 (BCL2) protein family members (P<0.01). Patient derived xenograft (PDX) data confirmed that the combination is more effective in abrogating tumor growth with prolonged survival than single-agent treatment (P<0.01). The novel combination of clofarabine and pictilisib in GC promotes DNA damage and inhibits key cell survival pathways to induce cell death beyond single-agent treatment.

Acute Lymphoblastic Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Cost-Effectiveness of Tisagenlecleucel in Paediatric Acute Lymphoblastic Leukaemia (pALL) and Adult Diffuse Large B-Cell Lymphoma (DLBCL) in Switzerland

INTRODUCTION

The purpose of the present analysis was to explore the cost-effectiveness of tisagenlecleucel in relapsed or refractory (r/r) paediatric acute lymphoblastic leukaemia (pALL) and r/r adult diffuse large B-cell lymphoma (DLBCL) in Switzerland against a range of historical standard-of-care treatments.

METHODS

Two cost-utility models were constructed for the two licensed indications using similar methodologies but indication-specific data. Clinical efficacy data were based on pooled analyses of clinical trials for tisagenlecleucel (pALL: ELIANA, ENSIGN, B2101J; DLBCL: JULIET, NCT02030834) and published data for comparator treatments. Treatment effects were compared based on matching-adjusted indirect comparison (MAIC) analyses. Four clinical lymphoma and leukaemia experts provided Switzerland-specific input regarding comparators, diagnostic and therapeutic procedures, clinical evidence and costs, which were used to inform the models. The base case analysis reflected the perspective of the Swiss mandatory health insurance system. Deterministic, probabilistic and scenario analyses were carried out to explore the robustness of results.

RESULTS

The base case analysis resulted in incremental costs of CHF 31,961-CHF 36,419 per quality-adjusted life year (QALY) gained for pALL across the different comparators and CHF 113,179 for DLBCL (1 CHF = 1.09 USD). Incremental costs per life-year gained ranged between CHF 33,906-CHF 97,399 across the two indications. Including productivity gains, tisagenlecleucel was shown to be dominant (more effective and less costly) over all the comparators for pALL and to result in incremental costs per life-year gained of CHF 57,324 for DLBCL.

CONCLUSION

Using hypothetical willingness-to-pay thresholds of CHF 100,000-150,000 per QALY gained, the present analysis has shown tisagenlecleucel to be a cost-effective treatment option in pALL and DLBCL.

A Prospective Investigation of Bispecific CD19/22 CAR T Cell Therapy in Patients With Relapsed or Refractory B Cell Non-Hodgkin Lymphoma

Background

The use of T cells expressing chimeric antigen receptor (CAR T) engineered to target CD19 constitutes breakthrough treatment for relapsed or refractory B cell non-Hodgkin lymphoma (R/R B-NHL). Despite improved outcomes, high relapse rate remains a challenge to overcome. Here, we report the clinical results and the pharmacokinetics of bispecific CD19/22 CAR T in patients with R/R B-NHL.

Methods

We performed a prospective, single-arm study of bispecific CD19/22 CAR T cells in R/R B-NHL. We analyzed the safety and efficacy and investigated the kinetic profiles of the CAR T cells. CAR transgene levels were measured using quantitative polymerase chain reaction, and correlation analyses of pharmacodynamic markers and product characteristics, disease conditions, clinical efficacy and adverse events were performed.

Results

From August 2017 to September 2020, a total of 32 patients with CD19/22 CAR T administration were analyzed. The overall response rate was 79.3%, and the complete response rate was 34.5%. The progression-free survival (PFS) and overall survival (OS) rates at 12 months were 40.0% and 63.3%, respectively. Among patients who had a CR at 3 months, the PFS and OS rates at 12 months were 66.7% and 100%, respectively. Severe cytokine release syndrome (sCRS) (grade 3 and higher) occurred in nine patients (28.1%). Grade 3 or higher neurologic events occurred in four patients (12.5%). One patient died from irreversible severe CRS-associated acute kidney injury. Long-term CAR T cells persistence correlated with clinical efficacy (133 days vs 22 days, P = 0.004). Patients treated with more than three prior therapies and presenting extranodal organ involvement had lower maximal concentration (C_max) values than other patients. Responders had higher C_max and area under the curve values than non-responders. Tumour burden and C_max were potentially associated with the severity of CRS.

Conclusions

This study demonstrates the safety and potential clinical efficacy of bispecific CD19/22 CAR T cells in patients with R/R B-NHL and highlights the importance of measuring kinetic parameters in PB to predict efficacy and safety in clinical applications of CAR T cell therapy.

Clinical Trial Registration

https://www.clinicaltrials.gov/ct2/show/NCT03196830, identifier NCT03196830.

Phase 1 study of bendamustine in combination with clofarabine, etoposide, and dexamethasone in pediatric patients with relapsed or refractory hematologic malignancies

BACKGROUND

A phase 1 study was conducted to determine the maximum tolerated dose of bendamustine when given in combination with clofarabine, etoposide, and dexamethasone daily for 5 days in children and adolescents with relapsed or refractory hematologic malignancies.

METHODS

Patients younger than 22 years with second or greater relapsed or refractory acute leukemia or lymphoma after 2 or more prior regimens were eligible. With the rolling 6 design, participants received escalating doses of bendamustine (30, 40, or 60 mg/m² /d) in combination with clofarabine (40 mg/m² ), etoposide (100 mg/m² ), and dexamethasone (8 mg/m² ) daily for 5 days. Optional pharmacokinetic studies were performed in cycle 1 on day 1 and day 5.

RESULTS

Sixteen patients were enrolled. Six patients were treated at the dose level of 30 mg/m² /d, 6 were treated at the dose level of 40 mg/m² /d, and 4 were treated at the dose level of 60 mg/m² /d. The dose-limiting toxicity was prolonged myelosuppression. The combination was otherwise well tolerated. The recommended dose of bendamustine in this combination was 30 mg/m² /d for 5 days. Ten responses were observed after 1 cycle: 6 complete remissions, 1 durable minimal residual disease-negative complete remission without platelet recovery in a patient with early T-cell precursor leukemia, and 3 partial remissions. Six patients proceeded to transplantation. The event-free survival rate was 40.6% (95% confidence interval [CI], 17.5%-63.7%) at 1 year and 33.9% (95% CI, 11.9%-55.9%) at 3 years.

CONCLUSIONS

Bendamustine is well tolerated in combination with clofarabine, etoposide, and dexamethasone. The combination administered over 5 days is effective for multiple relapsed and refractory hematologic malignancies. This trial is registered with ClinicalTrials.gov (NCT01900509).

LAY SUMMARY

Improvements to the existing chemotherapy regimen are still needed for patients who relapse after targeted therapies and immunotherapies and for those who are not eligible for or have no access to such therapies. A regimen combining cyclophosphamide, clofarabine, and etoposide has been used in relapsed and refractory pediatric patients with hematologic malignancies. This study shows that substituting bendamustine for cyclophosphamide in combination with clofarabine and etoposide is safe and effective.

Pediatric Acute Lymphoblastic Leukemia, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Advancements in technology that enhance our understanding of the biology of the disease, risk-adapted therapy, and enhanced supportive care have contributed to improved survival rates. However, additional clinical management is needed to improve outcomes for patients classified as high risk at presentation (eg, T-ALL, infant ALL) and who experience relapse. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for pediatric ALL provide recommendations on the workup, diagnostic evaluation, and treatment of the disease, including guidance on supportive care, hematopoietic stem cell transplantation, and pharmacogenomics. This portion of the NCCN Guidelines focuses on the frontline and relapsed/refractory management of pediatric ALL.

Effectiveness and Safety of Clofarabine Monotherapy or Combination Treatment in Relapsed/Refractory Childhood Acute Lymphoblastic Leukemia: A Pragmatic, Non-interventional Study in Korea

Purpose

Effectiveness and safety of clofarabine (one of the treatment mainstays in pediatric patients with relapsed/refractory acute lymphoblastic leukemia [ALL]) was assessed in Korean pediatric patients with ALL to facilitate conditional coverage with evidence development.

Materials and Methods

In this multicenter, prospective, observational study, patients receiving clofarabine as mono/combination therapy were followed up every 4–6 weeks for 6 months or until hematopoietic stem cell transplantation (HSCT). Response rates, survival outcomes, and adverse events were assessed.

Results

Sixty patients (2–26 years old; 65% B-cell ALL, received prior ≥ 2 regimen, 68.3% refractory to previous regimen) were enrolled and treated with at least one dose of clofarabine; of whom 26 (43.3%) completed 6 months of follow-up after the last dose of clofarabine. Fifty-eight patients (96.7%) received clofarabine combination therapy. Overall remission rate (complete remission [CR] or CR without platelet recovery [CRp]) was 45.0% (27/60; 95% confidence interval [CI], 32.4 to 57.6) and the overall response rate (CR, CRp, or partial remission [PR]) was 46.7% (28/60; 95% CI, 34.0 to 59.3), with 11 (18.3%), 16 (26.7%), and one (1.7%) patients achieving CR, CRp, and PR, respectively. The median time to remission was 5.1 weeks (95% CI, 4.7 to 6.1). Median duration of remission was 16.6 weeks (range, 2.0 to 167.6 weeks). Sixteen patients (26.7%) proceeded to HSCT. There were 24 deaths; 14 due to treatment-emergent adverse events.

Conclusion

Remission with clofarabine was observed in approximately half of the study patients who had overall expected safety profile; however, there was no favorable long-term survival outcome in this study.

Total Body Irradiation Forever? Optimising Chemotherapeutic Options for Irradiation-Free Conditioning for Paediatric Acute Lymphoblastic Leukaemia

Total-body irradiation (TBI) based conditioning prior to allogeneic hematopoietic stem cell transplantation (HSCT) is generally regarded as the gold-standard for children >4 years of age with acute lymphoblastic leukaemia (ALL). Retrospective studies in the 1990's suggested better survival with irradiation, confirmed in a small randomised, prospective study in the early 2000's. Most recently, this was reconfirmed by the early results of the large, randomised, international, phase III FORUM study published in 2020. But we know survivors will suffer a multitude of long-term sequelae after TBI, including second malignancies, neurocognitive, endocrine and cardiometabolic effects. The drive to avoid TBI directs us to continue optimising irradiation-free, myeloablative conditioning. In chemotherapy-based conditioning, the dominant myeloablative effect is provided by the alkylating agents, most commonly busulfan or treosulfan. Busulfan with cyclophosphamide is a long-established alternative to TBI-based conditioning in ALL patients. Substituting fludarabine for cyclophosphamide reduces toxicity, but may not be as effective, prompting the addition of a third agent, such as thiotepa, melphalan, and now clofarabine. For busulfan, it's wide pharmacokinetic (PK) variability and narrow therapeutic window is well-known, with widespread use of therapeutic drug monitoring (TDM) to individualise dosing and control the cumulative busulfan exposure. The development of first-dose selection algorithms has helped achieve early, accurate busulfan levels within the targeted therapeutic window. In the future, predictive genetic variants, associated with differing busulfan exposures and toxicities, could be employed to further tailor individualised busulfan-based conditioning for ALL patients. Treosulfan-based conditioning leads to comparable outcomes to busulfan-based conditioning in paediatric ALL, without the need for TDM to date. Future PK evaluation and modelling may optimise therapy and improve outcome. More recently, the addition of clofarabine to busulfan/fludarabine has shown encouraging results when compared to TBI-based regimens. The combination shows activity in ALL as well as AML and deserves further evaluation. Like busulfan, optimization of chemotherapy conditioning may be enhanced by understanding not just the PK of clofarabine, fludarabine, treosulfan and other agents, but also the pharmacodynamics and pharmacogenetics, ideally in the context of a single disease such as ALL.

Cost-Effectiveness Analysis of Tisagenlecleucel for the Treatment of Pediatric and Young Adult Patients with Relapsed or Refractory B Cell Acute Lymphoblastic Leukemia in Japan

Until recently, treatment options were relatively limited for children and young adults with relapsed or refractory (r/r) acute lymphoblastic leukemia (ALL). Tisagenlecleucel is a chimeric antigen receptor T cell (CAR-T) immunotherapy with promising efficacy and manageable safety that was approved in Japan in 2019 for the treatment of CD19-positive r/r B cell ALL (B-ALL). However, there is no publication assessing the cost-effectiveness of CAR-T in Japan. The objective of this study was to assess the cost-effectiveness of a tisagenlecleucel treatment strategy compared to a blinatumomab treatment strategy and a clofarabine combination treatment strategy (i.e., clofarabine + cyclophosphamide + etoposide) in Japan for pediatric and young adult patients up to 25 years of age with r/r B-ALL. A partitioned survival model with a lifetime horizon and monthly cycle was constructed from a Japanese public healthcare payer's perspective. Patients were distributed across the following partitioned health states: event-free survival (EFS), progressive disease, and death, which were informed by the EFS and overall survival (OS) data of respective clinical trials before year 5. For the tisagenlecleucel arm, a decision-tree structure was used to partition patients based on the infusion status; those who discontinued prior to receiving infusion were assigned efficacy and cost inputs of blinatumomab and those who received infusion were assigned efficacy and costs inputs based on tisagenlecleucel-infused patients. As trial data for blinatumomab and clofarabine ended before year 5, matching-adjusted indirect comparisons were used to extrapolate OS between the end of trial observation and up to year 5. All surviving patients followed the mortality risk of long-term ALL survivors without additional risk of disease relapse after year 5, regardless of initial treatment strategies. The model accounted for pretreatment costs, treatment costs, adverse event costs, follow-up costs, subsequent allogeneic hematopoietic stem cell transplantation costs, and terminal care costs. Incremental cost-effectiveness ratios (ICERs) per life-years (LYs) gained and ICERs per quality-adjusted life-years (QALYs) gained were evaluated using a 2% discount rate, and a threshold of ¥7.5 million was used to assess cost-effectiveness. Deterministic and probabilistic sensitivity analyses were performed. The total LYs (discounted) for tisagenlecleucel, blinatumomab, and clofarabine combination treatment strategies were 13.3, 4.0, and 2.7 years, respectively; the corresponding QALYs were 11.6, 3.1, and 2.1 years, respectively. The ICERs per QALY gained for tisagenlecleucel were ¥2,035,071 versus blinatumomab and ¥2,644,702 versus clofarabine combination therapy. Extensive sensitivity analyses supported the findings. Tisagenlecleucel is a cost-effective treatment strategy for pediatric and young adult patients with r/r B-ALL from a Japanese public healthcare payer's perspective.

Combination of clofarabine, etoposide, and cyclophosphamide in adult relapsed/refractory acute lymphoblastic leukemia: a phase 1/2 dose-escalation study by the Japan Adult Leukemia Study Group

This phase 1/2 study aimed to identify the maximum tolerated dose, the recommended phase 2 dose (RP2D), and efficacy of the clofarabine, etoposide, and cyclophosphamide combination regimen in adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL). Patients aged ≥ 15 years with relapsed/refractory ALL were enrolled. Escalating doses of clofarabine (20-30 mg/m²/day × 5 days), etoposide (50-100 mg/m²/day × 5 days), and cyclophosphamide (200-440 mg/m²/day × 5 days) were administered. Dose-limiting toxicity was defined as Grade 3 or more non-hematological toxicities and others. A total of 18 patients (B-ALL; n = 13, T-ALL; n = 5) were recruited in phase 1; however, the protocol was amended to close study without proceeding to phase 2. Three patients were enrolled in cohort 1, three in cohort 2, six in cohort 3, and six in cohort 4. The RP2D of clofarabine, etoposide, and cyclophosphamide was 30, 100, and 440 mg/m² daily, respectively. Complete remission (CR) was achieved in four patients (22%) and CR without platelet recovery in four patients (22%), with an overall response rate of 44%. The RP2D of the combination therapy was successfully determined in this study.

Cost-effectiveness of Anti-CD19 chimeric antigen receptor T-Cell therapy in pediatric relapsed/refractory B-cell acute lymphoblastic leukemia. A societal view

INTRODUCTION

In several studies, the chimeric antigen receptor T-cell therapy tisagenlecleucel demonstrated encouraging rates of remission and lasting survival benefits in pediatric patients with relapsed/refractory (r/r) acute lymphoblastic leukemia (ALL). We assessed the cost-effectiveness of tisagenlecleucel (list price: 320 000 EUR) among these patients when compared to clofarabine monotherapy (Clo-M), clofarabine combination therapy (Clo-C), and blinatumomab (Blina) from both a healthcare and a societal perspective. We also assessed future medical and future non-medical consumption costs.

METHODS

A three-state partitioned survival model was used to simulate a cohort of pediatric patients (12 years of age) through different disease states until the end of life (lifetime horizon). Relevant outcomes were life years, quality-adjusted life years (QALYs), healthcare costs, societal costs, and the incremental cost-effectiveness ratio (ICER). Uncertainty was explored through deterministic and probabilistic sensitivity analyses as well as through several scenario analyzes.

RESULTS

Total discounted costs for tisagenlecleucel were 552 679 EUR from a societal perspective, which was much higher than the total discounted costs from a healthcare perspective (ie, 409 563 EUR). Total discounted societal costs for the comparator regimens ranged between 160 803 EUR for Clo-M and 267 259 EUR for Blina. Highest QALYs were estimated for tisagenlecleucel (11.26), followed by Blina (2.25), Clo-C (1.70) and Clo-M (0.74). Discounted societal ICERs of tisagenlecleucel ranged between 31 682 EUR/QALY for Blina and 37 531 EUR/QALY for Clo-C and were considered cost-effective with a willingness-to-pay (WTP) threshold of 80 000 EUR/QALY. None of the scenarios exceeded this threshold, and more than 98% of the iterations in the probabilistic sensitivity analysis were cost-effective.

DISCUSSION

At the current price and WTP threshold, tisagenlecleucel is cost-effective from both a healthcare and a societal perspective. Nevertheless, long-term effectiveness data are needed to validate the several assumptions that were necessary for this model.

Estimation of Total Costs in Pediatric and Young Adult Patients with Relapsed or Refractory Acute Lymphoblastic Leukemia Receiving Tisagenlecleucel from a U.S. Hospital's Perspective

BACKGROUND

Tisagenlecleucel was approved for the treatment of pediatric and young adult patients with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (ALL) based on the pivotal ELIANA trial.

OBJECTIVE

To comprehensively evaluate the total costs associated with tisagenlecleucel treatment, including costs from pre- to postinfusion periods of tisagenlecleucel in addition to the cost of tisagenlecleucel.

METHODS

An economic model was developed to estimate total costs associated with tisagenlecleucel treatment from the time of leukapheresis to 2 months postinfusion from a U.S. hospital's perspective. Costs were estimated based on resource use and safety management from the ELIANA trial and were considered during the pretreatment, tisagenlecleucel infusion, and follow-up periods of treatment. Cost components included leukapheresis, lymphodepleting chemotherapy, tisagenlecleucel infusion and hospital administration, inpatient and intensive care unit admissions, medical professional visits, laboratory tests and procedures, and management of major adverse events. Scenario analyses were conducted by varying key assumptions related to adverse events and hospitalization.

RESULTS

The total cost associated with tisagenlecleucel treatment among pediatric and young adult patients with r/r ALL was estimated to be $612,779, of which $137,636 (22.5%) was in addition to the list price of tisagenlecleucel ($475,000) and the associated administration cost of $143.08. The top 3 drivers of the additional cost were adverse event management ($70,968; 51.6%), inpatient and intensive care unit admissions not attributed to adverse events ($57,952; 42.1%), and laboratory tests and procedures ($5,209; 3.8%). The costs incurred during the pretreatment, infusion, and follow-up periods were $29,002, $476,659, and $107,118, respectively. In the scenario analyses, the total costs ranged from $483,169 (tisagenlecleucel treatment in the outpatient setting without adverse events) to $672,373 (tisagenlecleucel treatment in the inpatient setting with grade 3/4 cytokine release syndrome and B-cell aplasia).

CONCLUSIONS

In this economic model, tisagenlecleucel treatment among pediatric and young adult patients with r/r ALL was estimated to cost $612,779. The cost of care in addition to the price of tisagenlecleucel accounted for 22.5% of the total, with adverse event management and inpatient and intensive care unit admissions being main drivers. Further studies are warranted to assess the cost of tisagenlecleucel treatment in the context of current standards of care in real-world clinical practice.

DISCLOSURES

This study was supported by Novartis. The study sponsor was involved in several aspects of the research, including the study design, the interpretation of data, the writing of the manuscript, and the decision to submit the manuscript for publication. Hao is an employee of Novartis and has stock/stock options. Yang, Chai, Qi, and Wu are employees of Analysis Group, which received consulting fees from Novartis for work on this study. Part of the material in this manuscript was presented at the American Society of Hematology Annual Meeting held December 7-10, 2019, in Orlando, FL.

CAR T-cell product performance in haematological malignancies before and after marketing authorisation

Chimeric antigen receptor (CAR) T cells represent a potent new approach to treat haematological malignancies. Two CAR T-cell therapies, tisagenlecleucel and axicabtagene ciloleucel, have been approved in Europe and the USA, as well as several other countries, for the treatment of leukaemia and lymphoma. These approvals marked a major milestone in the field of cell and gene therapies. However, the clinical development and regulatory evaluation of these innovative therapies faced several challenges that are considered important lessons learned for future similar products. Here, we examine the products' non-clinical and clinical data packages to outline the challenges encountered during the regulatory evaluation process in Europe, and to provide an update on their performance after authorisation.

Tisagenlecleucel versus historical standard therapies for pediatric relapsed/refractory acute lymphoblastic leukemia

Aim: We compared outcomes from a single-arm study of tisagenlecleucel with standard of care (SOC) regimens in pediatric and young adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL). Methods: The analysis included one tisagenlecleucel study, one blinatumomab study, one clofarabine monotherapy study, three studies of clofarabine combination regimens and two studies of other salvage chemotherapy. Matching-adjusted indirect comparison analyses were conducted. Results: After adjusting for baseline characteristics, tisagenlecleucel was associated with significantly prolonged overall survival compared with blinatumomab (hazard ratio [95% CI], 0.32 [0.16-0.64]); clofarabine monotherapy (0.24 [0.13-0.42]); clofarabine combination regimens (0.26 [0.15-0.45]); two salvage therapies (0.15 [0.09-0.25] and 0.27 [0.15-0.49]). Conclusion: The analysis demonstrated tisagenlecleucel was associated with substantially greater survival benefit versus all SOC regimens.

CAG regimen for refractory or relapsed adult T-cell acute lymphoblastic leukemia: A retrospective, multicenter, cohort study

Adult patients with relapsed or refractory T‐cell acute lymphoblastic leukemia (R/R‐T‐ALL) have extremely poor prognosis, representing an urgent unmet medical need. Finding an optimal salvage regimen to bridge transplantation is a priority. The CAG (cytarabine, aclarubicin, and G‐CSF) regimen was initially used by one group in China, showing unexpectedly promising results in 11 R/R‐T‐ALL patients. Here, we report the multicenter results of 41 patients who received the CAG regimen as salvage therapy. After one cycle of the CAG regimen, complete remission and partial remission were achieved in 33 (80.5%) and two (4.9%) patients, respectively. Failure to respond was observed in six patients (14.6%). Early T‐cell precursor (ETP) (n = 26) and non‐ETP (n = 15) patients had a similar CR rate (80.8% vs 80.0%, P = .95). Among 41 patients, allo‐HSCT was successfully performed in 27 (66%) patients (22 in CR and 5 in non‐CR). With a median follow‐up time of 12 months, the estimated 2‐year overall survival and event‐free survival were 68.8% (95% CI, 47.3%‐83.0%) and 56.5% (95% CI, 37.1%‐71.9%), respectively. The CAG regimen was well‐tolerated, and no early death occurred. Our multicenter results show that the CAG regimen is highly effective and safe, representing a novel choice for adult patients with R/R‐T‐ALL and providing a better bridge to transplantation.

Optimization of a clofarabine-based drug combination regimen for the preclinical evaluation of pediatric acute lymphoblastic leukemia

BACKGROUND

The aim of this study was to improve the predictive power of patient-derived xenografts (PDXs, also known as mouse avatars) to more accurately reflect outcomes of clofarabine-based treatment in pediatric acute lymphoblastic leukemia (ALL) patients.

PROCEDURE

Pharmacokinetic (PK) studies were conducted using clofarabine at 3.5 to 15 mg/kg in mice. PDXs were established from relapsed/refractory ALL patients who exhibited good or poor responses to clofarabine. PDX engraftment and response to clofarabine (either as a single agent or in combinations) were assessed based on stringent objective response measures modeled after the clinical setting.

RESULTS

In naïve immune-deficient NSG mice, we determined that a clofarabine dose of 3.5 mg/kg resulted in systemic exposures equivalent to those achieved in pediatric ALL patients treated with clofarabine-based regimens. This dose was markedly lower than the doses of clofarabine used in previously reported preclinical studies (typically 30-60 mg/kg) and, when scheduled consistent with the clinical regimen (daily × 5), resulted in 34-fold lower clofarabine exposures. Using a well-tolerated clofarabine/etoposide/cyclophosphamide combination regimen, we then found that the responses of PDXs better reflected the clinical responses of the patients from whom the PDXs were derived.

CONCLUSIONS

This study has identified an in vivo clofarabine treatment regimen that reflects the clinical responses of relapsed/refractory pediatric ALL patients. This regimen could be used prospectively to identify patients who might benefit from clofarabine-based treatment. Our findings are an important step toward individualizing prospective patient selection for the use of clofarabine in relapsed/refractory pediatric ALL patients and highlight the need for detailed PK evaluation in murine PDX models.

Targeting RAD51 enhances chemosensitivity of adult T‑cell leukemia‑lymphoma cells by reducing DNA double‑strand break repair

RAD51, is a key homologous recombination protein that repairs DNA damage and maintains gene diversity and stability. Previous studies have demonstrated that the over‑expression of RAD51 is associated with chemotherapy resistance of tumor cells to chemotherapy, and enhanced activity of DNA damage repair (DDR) systems contributes to resistance of adult T‑cell leukemia‑lymphoma (ATL) resistance to chemotherapy. Thus, targeting RAD51 is a potential strategy for the sensitization of ATL cells to chemotherapeutic drugs by inducing DNA damage. In general, cells can repair minor DNA damage through DDR; however, serious DNA damage may cause cell toxicity in cells which cannot be restored. In the present, down regulation of RAD51 by shRNA and imatinib sensitized Jurkat cells to etoposide by decreasing the activity of homologous recombination (HR). We found that the suppression of RAD51 by shRNA inhibited tumor cells proliferation and enhanced apoptosis of Jurkat cells after etoposide treatment. Importantly, downregulation of RAD51 by imatinib obviously increased the apoptosis of Jurkat cell after etoposide treatment. These results demonstrated that RAD51 may be of great value to as a novel target for the clinical treatment of adult T‑cell leukemia‑lymphoma (ATL), and it may improve the survival of leukemia patients.

Is it a Chimera? A systematic review of the economic evaluations of CAR-T cell therapy

Introduction: The new category of chimeric antigen receptor T - cell raised hopes for a more effective treatment of large B cell lymphoma and acute lymphoblastic leukemia. Nevertheless, their soaring acquisition costs will stretch the fiscal capacity of the health systems worldwide. To this direction, the scope of this study is to provide a systematic review of their economic evaluations. Areas covered: A systematic review of the economic evaluations of tisagenlecleucel and axicabtagene was performed. Expert opinion: The available data indicate that these products demonstrate a potentially favorable cost-effectiveness ratio. Nevertheless, their budget impact is of overriding importance and it should be incorporated in any economic evaluation. Moreover, more affirmative clinical data are imperative in order to mitigate uncertainty.

Cost-Effectiveness of Chimeric Antigen Receptor T-Cell Therapy in Pediatric Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia

BACKGROUND

Chimeric antigen receptor T-cell (CAR-T) therapy is a promising new class of cancer therapy but has a high up-front cost. We evaluated the cost-effectiveness of CAR-T therapy among pediatric patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL).

METHODS

We built a microsimulation model for pediatric patients with relapsed/refractory B-ALL receiving either CAR-T therapy or standard of care. Outcomes included costs, quality of life (health utility), complications, and survival. We measured cost-effectiveness with the incremental cost-effectiveness ratio (ICER), with ICERs under $100 000 per quality-adjusted life-year (QALY) considered cost effective. One-way and probabilistic sensitivity analyses were used to test model uncertainty.

RESULTS

Compared to standard of care, CAR-T therapy increased overall cost by $528 200 and improved effectiveness by 8.18 QALYs, resulting in an ICER of $64 600/QALY. The model was sensitive to assumptions about long-term CAR-T survival, the complete remission rate of CAR-T patients, and the health utility of long-term survivors. The base model assumed a 76.0% one-year survival with CAR-T, although if this decreased to 57.8%, then CAR-T was no longer cost effective. If the complete remission rate of CAR-T recipients decreased from 81% to 56.2%, or if the health utility of disease-free survivors decreased from 0.94 to 0.66, then CAR-T was no longer cost effective. Probabilistic sensitivity analysis found that CAR-T was cost effective in 94.8% of iterations at a willingness to pay of $100 000/QALY.

CONCLUSION

CAR-T therapy may represent a cost-effective option for pediatric relapsed/refractory B-ALL, although longer follow-up of CAR-T survivors is required to confirm validity of these findings.

Cyclophosphamide for the treatment of acute lymphoblastic leukemia: A protocol for systematic review

BACKGROUND

Previous clinical trials have reported that cyclophosphamide can be used for the treatment of acute lymphoblastic leukemia (ALL). However, its efficacy is still unclear. In this systematic review study, we aim to evaluate its efficacy and safety for ALL.

METHODS

The following 9 databases will be searched from their inception to the present: Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), and four Chinese databases. The randomized controlled trials or case control studies of cyclophosphamide that assess the clinical efficacy and safety in patients with ALL are included. The methodological quality of all eligible included studies will be assessed by the Cochrane risk of bias tool.The primary outcome measurement will be all-cause mortality at the period of treatment and follow-up. The secondary outcome measurements will include the health-related quality of life (HRQL), postinduction complete remission (CR) rate, event-free survival (EFS), relapse rate, and adverse events. Two authors will independently select eligible studies, exact data, and assess the methodological quality of included studies. RevMan 5.3 software will be used to synthesize the data. Reporting bias will be evaluated by the funnel plots, Begg, and Egger tests.

RESULTS

This systematic review will evaluate the clinical efficacy and safety of cyclophosphamide for ALL.

DISSEMINATION AND ETHICS

The findings of this review will summarize the present evidence of cyclophosphamide for ALL, and may provide guidance for clinical practice of cyclophosphamide for ALL. Its results will be published through peer-reviewed journals. This study does not need ethic approval, because it will not involve the individual data.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018119333.

Recent Advances in the Biology and Treatment of T Cell Acute Lymphoblastic Leukemia

PURPOSE OF REVIEW

This article provides an overview of the current knowledge regarding the biology and treatment of T cell acute lymphoblastic leukemia (T-ALL) and highlights the most recent findings in this field over the past 5 years.

RECENT FINDINGS

Remarkable progress has been made in the genomic landscape of T-ALL over the past few years. The discovery of activating mutations of NOTCH1 and FBXW7 in a majority of patients has been a seminal observation, with several early phase clinical trials currently exploring these as potential therapeutic targets. Characterization of early T cell precursor ALL, incorporation of minimal residual disease assessment into therapeutic protocols, and use of pediatric-intensive regimens along with judicious use of allogeneic HCT have significantly improved risk stratification and treatment outcomes. Improved risk stratification and the use of novel targeted therapies based on recent genomic discoveries are expected to change the therapeutic landscape of T-ALL and hopefully improve the outcomes of this historically poor prognosis disease.

Clinical Pharmacology of Tisagenlecleucel in B-cell Acute Lymphoblastic Leukemia

PURPOSE

Tisagenlecleucel is an anti-CD19 chimeric antigen receptor (CAR19) T-cell therapy approved for the treatment of children and young adults with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL).

PATIENTS AND METHODS

We evaluated the cellular kinetics of tisagenlecleucel, the effect of patient factors, humoral immunogenicity, and manufacturing attributes on its kinetics, and exposure-response analysis for efficacy, safety and pharmacodynamic endpoints in 79 patients across two studies in pediatric B-ALL (ELIANA and ENSIGN).

RESULTS

Using quantitative polymerase chain reaction to quantify levels of tisagenlecleucel transgene, responders (N = 62) had ≈2-fold higher tisagenlecleucel expansion in peripheral blood than nonresponders (N = 8; 74% and 104% higher geometric mean Cmax and AUC0-28d, respectively) with persistence measurable beyond 2 years in responding patients. Cmax increased with occurrence and severity of cytokine release syndrome (CRS). Tisagenlecleucel continued to expand and persist following tocilizumab, used to manage CRS. Patients with B-cell recovery within 6 months had earlier loss of the transgene compared with patients with sustained clinical response. Clinical responses were seen across the entire dose range evaluated (patients ≤50 kg: 0.2 to 5.0 × 10⁶/kg; patients >50 kg: 0.1 to 2.5 × 10⁸ CAR-positive viable T cells) with no relationship between dose and safety. Neither preexisting nor treatment-induced antimurine CAR19 antibodies affected the persistence or clinical response.

CONCLUSIONS

Response to tisagenlecleucel was associated with increased expansion across a wide dose range. These results highlight the importance of cellular kinetics in understanding determinants of response to chimeric antigen receptor T-cell therapy.

Replacing cyclophosphamide/cytarabine/mercaptopurine with cyclophosphamide/etoposide during consolidation/delayed intensification does not improve outcome for pediatric B-cell acute lymphoblastic leukemia: a report from the COG

With modern chemotherapy, approximately 90% of patients with pediatric acute lymphoblastic leukemia are now cured. However, subsets of patients can be identified who remain at very high risk of relapse with expected 4-year disease-free survival rates <80%; such patients are appropriate candidates for intensive therapeutic strategies designed to improve survival. The AALL1131 trial was designed to determine, in a randomized fashion, whether substitution with cyclophosphamide/etoposide (experimental arm 1) would improve the 4-year disease-free survival of children, adolescents, and young adults with very high-risk B-cell acute lymphoblastic leukemia compared to a modified Berlin-Frankfurt-Münster regimen (control arm). Patients 1-30 years of age with newly diagnosed very high-risk B-cell acute lymphoblastic leukemia were randomized after induction in a 1:2 fashion to the control arm or experimental arm 1 in which they were given cyclophosphamide (440 mg/m² days 1-5)/etoposide (100 mg/m² days 1-5) during part 2 of consolidation and delayed intensification. Prospective interim monitoring rules for efficacy and futility were included where futility would be determined for a one-sided P-value ≥0.7664. The study was stopped for futility as the interim monitoring boundary was crossed [hazard ratio 0.606 (95% confidence interval: 0.297 - 1.237)] and the very high-risk arm of AALL1131 was closed in February 2017. Using data current as of December 31, 2017, 4-year disease-free survival rates were 85.5±6.8% (control arm) versus 72.3±6.3% (experimental arm 1) (P-value = 0.76). There were no significant differences in grade 3/4 adverse events between the two arms. Substitution of this therapy for very high-risk B-cell acute lymphoblastic leukemia patients on the Children’s Oncology Group AALL1131 trial (NCT02883049) randomized to cyclophosphamide/etoposide during part 2 of consolidation and delayed intensification did not improve disease-free survival.

Inotuzumab ozogamicin in pediatric patients with relapsed/refractory acute lymphoblastic leukemia

Although inotuzumab ozogamicin (InO) is recognized as an effective agent in relapsed acute lymphoblastic leukemia (ALL) in adults, data on safety and efficacy in pediatric patients are scarce. We report the use of InO in 51 children with relapsed/refractory ALL treated in the compassionate use program. In this heavily pretreated cohort, complete remission was achieved in 67% of patients with overt marrow disease. The majority (71%) of responders were negative for minimal residual disease. Responses were observed irrespective of cytogenetic subtype or number or type of prior treatment regimens. InO was well-tolerated; grade 3 hepatic transaminitis or hyperbilirubinemia were noted in 6 (12%) and grade 3/4 infections in 11 (22%) patients. No patient developed sinusoidal obstruction syndrome (SOS) during InO therapy; however, 11 of 21 (52%) patients who underwent hematopoietic stem cell transplantation (HSCT) following InO developed SOS. Downregulation of surface CD22 was detected as a possible escape mechanism in three patients who developed a subsequent relapse after InO. We conclude that InO is a well-tolerated, effective therapy for children with relapsed ALL and prospective studies are warranted. Identification of risk factors for developing post-HSCT SOS and strategies to mitigate this risk are ongoing.

Clinical Pharmacology of Tisagenlecleucel in B-cell Acute Lymphoblastic Leukemia

PURPOSE

Tisagenlecleucel is an anti-CD19 chimeric antigen receptor (CAR19) T-cell therapy approved for the treatment of children and young adults with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL).

PATIENTS AND METHODS

We evaluated the cellular kinetics of tisagenlecleucel, the effect of patient factors, humoral immunogenicity, and manufacturing attributes on its kinetics, and exposure-response analysis for efficacy, safety and pharmacodynamic endpoints in 79 patients across two studies in pediatric B-ALL (ELIANA and ENSIGN).

RESULTS

Using quantitative polymerase chain reaction to quantify levels of tisagenlecleucel transgene, responders (N = 62) had ≈2-fold higher tisagenlecleucel expansion in peripheral blood than nonresponders (N = 8; 74% and 104% higher geometric mean Cmax and AUC0-28d, respectively) with persistence measurable beyond 2 years in responding patients. Cmax increased with occurrence and severity of cytokine release syndrome (CRS). Tisagenlecleucel continued to expand and persist following tocilizumab, used to manage CRS. Patients with B-cell recovery within 6 months had earlier loss of the transgene compared with patients with sustained clinical response. Clinical responses were seen across the entire dose range evaluated (patients ≤50 kg: 0.2 to 5.0 × 10⁶/kg; patients >50 kg: 0.1 to 2.5 × 10⁸ CAR-positive viable T cells) with no relationship between dose and safety. Neither preexisting nor treatment-induced antimurine CAR19 antibodies affected the persistence or clinical response.

CONCLUSIONS

Response to tisagenlecleucel was associated with increased expansion across a wide dose range. These results highlight the importance of cellular kinetics in understanding determinants of response to chimeric antigen receptor T-cell therapy.

Clofarabine, high-dose cytarabine and liposomal daunorubicin in pediatric relapsed/refractory acute myeloid leukemia: a phase IB study

Survival in children with relapsed/refractory acute myeloid leukemia is unsatisfactory. Treatment consists of one course of fludarabine, cytarabine and liposomal daunorubicin, followed by fludarabine and cytarabine and stem-cell transplantation. Study ITCC 020/I-BFM 2009-02 aimed to identify the recommended phase II dose of clofarabine replacing fludarabine in the abovementioned combination regimen (3+3 design). Escalating dose levels of clofarabine (20-40 mg/m²/day × 5 days) and liposomal daunorubicin (40-80 mg/m²/day) were administered with cytarabine (2 g/m²/day × 5 days). Liposomal DNR was given on day 1, 3 and 5 only. The cohort at the recommended phase II dose was expanded to make a preliminary assessment of anti-leukemic activity. Thirty-four children were enrolled: refractory 1^st (n=11), early 1st (n=15), ≥2^nd relapse (n=8). Dose level 3 (30 mg/m²clofarabine; 60 mg/m²liposomal daunorubicin) appeared to be safe only in patients without subclinical fungal infections. Infectious complications were dose-limiting. The recommended phase II dose was 40 mg/m² clofarabine with 60 mg/m² liposomal daunorubicin. Side-effects mainly consisted of infections. The overall response rate was 68% in 31 response evaluable patients, and 80% at the recommended phase II dose (n=10); 22 patients proceeded to stem cell transplantation. The 2-year probability of event-free survival (pEFS) was 26.5±7.6 and probability of survival (pOS) 32.4±8.0%. In the 21 responding patients, the 2-year pEFS was 42.9±10.8 and pOS 47.6±10.9%. Clofarabine exposure in plasma was not significantly different from that in single-agent studies. In conclusion, clofarabine was well tolerated and showed high response rates in relapsed/refractory pediatric acute myeloid leukemia. Patients with (sub) clinical fungal infections should be treated with caution. Clofarabine has been taken forward in the Berlin-Frankfurt-Münster study for newly diagnosed acute myeloid leukemia. The Study ITCC-020 was registered as EUDRA-CT 2009-009457-13; Dutch Trial Registry number 1880.

Clofarabine exerts antileukemic activity against cytarabine-resistant B-cell precursor acute lymphoblastic leukemia with low deoxycytidine kinase expression

Cytosine arabinoside (Ara-C) is one of the key drugs for the treatment of acute myeloid leukemia. It is also used for consolidation therapy of acute lymphoblastic leukemia (ALL). Ara-C is a deoxyadenosine analog and is phosphorylated to form cytosine arabinoside triphosphate (Ara-CTP) as an active form. In the first step of the metabolic pathway, Ara-C is phosphorylated to Ara-CMP by deoxycytidine kinase (DCK). However, the current cumulative evidence in the association of the Ara-C sensitivity in ALL appears inconclusive. We analyzed various cell lines for the possible involvement of DCK in the sensitivities of B-cell precursor ALL (BCP-ALL) to Ara-C. Higher DCK expression was associated with higher Ara-C sensitivity. DCK knockout by genome editing with a CRISPR-Cas9 system in an Ara-C-sensitive-ALL cell line induced marked resistance to Ara-C, but not to vincristine and daunorubicin, indicating the involvement of DCK expression in the Ara-C sensitivity of BCP-ALL. DCK gene silencing due to the hypermethylation of a CpG island and reduced DCK activity due to a nonsynonymous variant allele were not associated with Ara-C sensitivity. Clofarabine is a second-generation deoxyadenosine analog rationally synthesized to improve stability and reduce toxicity. The IC50 of clofarabine in 79 BCP-ALL cell lines was approximately 20 times lower than that of Ara-C. In contrast to Ara-C, although the knockout of DCK induced marked resistance to clofarabine, sensitivity to clofarabine was only marginally associated with DCK gene expression level, suggesting a possible efficacy of clofarabine for BCP-ALL that shows relative Ara-C resistance due to low DCK expression.

Toxicity associated with intensive postinduction therapy incorporating clofarabine in the very high-risk stratum of patients with newly diagnosed high-risk B-lymphoblastic leukemia: A report from the Children's Oncology Group study AALL1131

BACKGROUND

Children, adolescents, and young adults with very high-risk (VHR) B acute lymphoblastic leukemia (B-ALL) have poor outcomes, and novel therapies are needed for this subgroup. The AALL1131 study evaluated postinduction therapy using cyclophosphamide (CPM), etoposide (ETOP), and clofarabine (CLOF) for patients with VHR B-ALL.

METHODS

Patients who were 1 to 30 years old and had VHR B-ALL received modified Berlin-Frankfurt-Münster therapy after induction and were randomized to 1) CPM, cytarabine, mercaptopurine, vincristine (VCR), and pegaspargase (control arm), 2) CPM, ETOP, VCR, and pegaspargase (experimental arm 1), or 3) CPM, ETOP, CLOF (30 mg/m2 /d × 5), VCR, and pegaspargase (experimental arm 2) during the second half of consolidation and delayed intensification.

RESULTS

The rates of grade 4/5 infections and grade 3/4 pancreatitis were significantly increased in experimental arm 2. The dose of CLOF was, therefore, reduced to 20 mg/m2 /d × 5, and myeloid growth factor was required after CLOF administration. Despite these changes, 4 of 39 patients (10.3%) developed grade 4 infections, with 1 of these patients developing a grade 5 acute kidney injury attributed to CLOF, whereas only 1 of 46 patients (2.2%) in experimental arm 1 developed grade 4 infections, and there were no grade 4/5 infections in the control arm (n = 20). Four patients in experimental arm 2 had prolonged cytopenias for >60 days, whereas none did in the control arm or experimental arm 1. Counts failed to recover for 2 of these patients, one having a grade 5 acute kidney injury and the other removed from protocol therapy; both events occurred 92 days after the start of consolidation part 2.

CONCLUSIONS

In AALL1131, CLOF, administered with CPM and ETOP, was associated with unacceptable toxicity. Cancer 2018;124:1150-9. © 2017 American Cancer Society.

Efficacy and safety of G-CSF, low-dose cytarabine and aclarubicin in combination with l-asparaginase, prednisone in the treatment of refractory or relapsed acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) patients who fail to acquire complete remission (CR) or who relapse after initial response have poor prognosis. At present there is no consensus as to the standard salvage therapy for these patients. In this study, we retrospectively evaluate safety and efficacy of a salvage regimen (CAGLP) consisting of G-CSF, low-dose cytarabine, aclarubicin, l-asparaginase and prednisone. Thirty-six patients were included with primary refractory (n=13) or relapse (n=23). The overall response rate (ORR) and CR rate were 86.1% and 63.9%, respectively. With a median follow-up of 34 months, the probability of overall survival (OS) at 2 years was 30%±10% and the disease-free survival (DFS) rate was 15%±8%. Treatment-related mortality was 5.6%. Our preliminary results indicated that CAGLP was feasible, safe and effective as a salvage reinduction chemotherapy for primary refractory and relapsed ALL patients.