The Choice of Either Conventional Chemotherapy or Inotuzumab Ozogamicin as Bridging Regimen Does Not Appear To Impact Clinical Response to CD19-Directed CAR-T Therapy in Pediatric B-ALL

Bridging therapy (BT) given during the period between T-cell collection and initiation of lymphodepleting chemotherapy is indicated for most children with B-cell acute lymphoblastic leukemia (B-ALL) undergoing treatment with tisagenlecleucel (tisa-cel), a CD19-directed chimeric antigen receptor T-cell (CAR-T) therapy. Both conventional chemotherapy agents and B-cell directed antibody-based therapies such as antibody-drug conjugates and bispecific T-cell engagers have been used as systemic forms of BT. The purpose of this retrospective study was to evaluate if there are detectable differences in clinical outcomes based on the type of BT given (conventional chemotherapy or inotuzumab). A retrospective analysis was performed on all patients treated with tisa-cel at Cincinnati Children's Hospital Medical Center for B-ALL with bone marrow disease (with or without extramedullary disease). Patients who did not receive systemic BT were excluded. Only 1 patient received blinatumomab as BT and was therefore not included in this analysis to focus the analysis on the use of inotuzumab. Pre-infusion characteristics and post-infusion outcomes were collected. Fisher's exact test was used for categorical variables, and t-test or Mann-Whitney test was used for continuous parametric and non-parametric variables respectively. Mantel-Cox was used for survival analyses. Thirty-two patients received BT before CD19 CAR-T for medullary leukemia; 24 received conventional chemotherapy, and 8 received inotuzumab ozogamicin (InO). Cohorts were evenly matched regarding CAR-T indication, recipient age, and median CAR-T cell dose. There were no significant differences between the groups for attaining a minimal residual disease (MRD)-negative complete response after CAR-T, the percentage of patients who maintained prolonged B-cell aplasia, or the median duration of B-cell aplasia. Thirty-seven percent of patients in the conventional chemotherapy group and 43% in the antibody-based therapy group relapsed, with a median time to relapse in both groups of 5 months. No differences in event-free survival, the cumulative incidence of relapse, or overall survival were seen between the two groups. Initial response to tisa-cel, relapse rate, and survival were similar between patients who received BT with conventional chemotherapy or InO therapy. Because low disease burden at the time of infusion is a positive prognostic factor, choice of bridging regimen should focus on therapy that is anticipated to effectively lower disease burden and minimize treatment-related toxicity. Given the limitations associated with the single center retrospective analysis, a larger, multicenter study is needed to further explore these findings.

Preclinical efficacy of azacitidine and venetoclax for infant KMT2A-rearranged acute lymphoblastic leukemia reveals a new therapeutic strategy

Infants with KMT2A-rearranged B-cell acute lymphoblastic leukemia (ALL) have a dismal prognosis. Survival outcomes have remained static in recent decades despite treatment intensification and novel therapies are urgently required. KMT2A-rearranged infant ALL cells are characterized by an abundance of promoter hypermethylation and exhibit high BCL-2 expression, highlighting potential for therapeutic targeting. Here, we show that hypomethylating agents exhibit in vitro additivity when combined with most conventional chemotherapeutic agents. However, in a subset of samples an antagonistic effect was seen between several agents. This was most evident when hypomethylating agents were combined with methotrexate, with upregulation of ATP-binding cassette transporters identified as a potential mechanism. Single agent treatment with azacitidine and decitabine significantly prolonged in vivo survival in KMT2A-rearranged infant ALL xenografts. Treatment of KMT2A-rearranged infant ALL cell lines with azacitidine and decitabine led to differential genome-wide DNA methylation, changes in gene expression and thermal proteome profiling revealed the target protein-binding landscape of these agents. The selective BCL-2 inhibitor, venetoclax, exhibited in vitro additivity in combination with hypomethylating or conventional chemotherapeutic agents. The addition of venetoclax to azacitidine resulted in a significant in vivo survival advantage indicating the therapeutic potential of this combination to improve outcome for infants with KMT2A-rearranged ALL.

Levocarnitine for pegaspargase-induced hepatotoxicity in older children and young adults with acute lymphoblastic leukemia

Background

Pegaspargase (PEG‐ASP) is an integral component of therapy for acute lymphoblastic leukemia (ALL) but is associated with hepatotoxicity that may delay or limit future therapy. Obese and adolescent and young adult (AYA) patients are at high risk. Levocarnitine has been described as potentially beneficial for the treatment or prevention of PEG‐ASP‐associated hepatotoxicity.

Methods

We collected data for patients age ≥10 years who received levocarnitine during induction therapy for ALL, compared to a similar patient cohort who did not receive levocarnitine. The primary endpoint was conjugated bilirubin (c.bili) >3 mg/dl. Secondary endpoints were transaminases >10× the upper limit of normal and any Grade ≥3 hepatotoxicity.

Results

Fifty‐two patients received levocarnitine for prophylaxis (n = 29) or rescue (n = 32) of hepatotoxicity. Compared to 109 patients without levocarnitine, more patients receiving levocarnitine were obese and/or older and had significantly higher values for some hepatotoxicity markers at diagnosis and after PEG‐ASP. Levocarnitine regimens varied widely; no adverse effects of levocarnitine were identified. Obesity and AYA status were associated with an increased risk of conjugated hyperbilirubinemia and severe transaminitis. Multivariable analysis identified a protective effect of levocarnitine on the development of c.bili >3 mg/dl (OR 0.12, p = 0.029). There was no difference between groups in CTCAE Grade ≥3 hepatotoxicity. C.bili >3 mg/dl during induction was associated with lower event‐free survival.

Conclusions

This real‐world data on levocarnitine supplementation during ALL induction highlights the risk of PEG‐ASP‐associated hepatotoxicity in obese and AYA patients, and hepatotoxicity's potential impact on survival. Levocarnitine supplementation may be protective, but prospective studies are needed to confirm these findings.

Treatment of posttransplant lymphoproliferative disorder with poor prognostic features in children and young adults: Short-course EPOCH regimens are safe and effective

No guidelines exist for which intensive chemotherapy regimen is best in pediatric or young adult patients with high-risk posttransplant lymphoproliferative disorder (PTLD). We retrospectively reviewed patients with PTLD who received interval-compressed short-course etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin (SC-EPOCH) regimens at our institution. Eight patients were included with median age of 12 years. All patients achieved a complete response with a manageable toxicity profile. Two patients developed second, clonally unrelated, EBV-positive PTLD and one patient had recurrence at 6 months off therapy. No graft rejection occurred during therapy. All eight patients are alive with median follow-up of 29 months.

Inotuzumab ozogamicin in infants and young children with relapsed or refractory acute lymphoblastic leukaemia: a case series

No data on inotuzumab ozogamicin (InO) in infant acute lymphoblastic leukaemia (ALL) have been published to date. We collected data internationally on infants/young children (<3 years) with ALL treated with InO. Fifteen patients (median 4.4 months at diagnosis) received InO due to relapsed or refractory (R/R) disease. Median percentage of CD22⁺ blasts was 72% (range 40-100%, n = 9). The median dose in the first course was 1.74 mg/m² (fractionated). Seven patients (47%) achieved complete remission; one additional minimal residual disease (MRD)-positive patient became MRD-negative. Six-month overall survival was 47% (95% confidence interval [CI] 27-80%). Two patients developed veno-occlusive disease after transplant. Further evaluation of InO in this subgroup of ALL is justified.

Experiences of a Multidisciplinary Genomic Tumor Board Interpreting Risk for Underlying Germline Variants in Tumor-Only Sequencing Results

PURPOSE

Although analyzing germline and tumor samples concurrently provides the best opportunity for differentiating between germline and somatic mutations, tumor-only sequencing is becoming increasingly common in clinical care. The purpose of this study is to assess how a multidisciplinary genomic tumor board (MGTB) evaluated patients’ tumor-only sequencing results and made genetics referrals. With limited professional society guidance on how to manage pathogenic mutations identified via tumor-only sequencing, this study contemplates the professional knowledge and skills necessary to have represented on an MGTB to interpret these results in context of potential germline findings.

METHODS

Qualitative interviews with MGTB members and an ethnographic case study of a breast cancer MGTB at a National Cancer Institute cancer center were examined.

RESULTS

This MGTB discussed 34 cases of women with advanced-stage breast cancer over 13 months. Interviews and observations of MGTB meetings indicated that members of the MGTB contemplated whether variants were germline or somatic and potential for identification of germline cancer predisposition. On the basis of existing professional society guidelines, 18 patients would be eligible for germline testing. However, the MGTB only referred 11 patients (61%) for additional germline testing, and the remaining seven patients (39%) were not referred, raising questions about the kind of genomic expertise needed on an MGTB to optimize results interpretation and referrals.

CONCLUSION

To ensure adequate interpretation, recommendation, and communication of tumor sequencing results, an MGTB should include professionals with knowledge and experience in clinical translation of tumor sequencing, testing methodology, molecular pathology, cancer biology, genomic pathways, germline variant interpretation, evaluation of family history, and application of professional recommendations for germline testing after tumor-only sequencing. These skills may not be held by a single professional on an MGTB.

Capped antithrombin III dosing is cost effective in the management of asparaginase-associated thrombosis

Asparaginase therapy induces a transient antithrombin III (ATIII) deficiency, which contributes to the risk of asparaginase-induced thrombosis. At Cincinnati Children's Hospital Medical Center, management of asparaginase-induced thrombosis includes ATIII supplementation during therapeutic anticoagulation with enoxaparin. Due to the expense associated with ATIII, a capped dosing approach for ATIII was evaluated in this population. Peak ATIII levels were obtained following capped doses to evaluate response. In this pilot evaluation, 11 patients received a total of 138 capped doses for a total cost savings of $803 782. This pilot evaluation represents the first reported analysis of capped ATIII dosing in oncology patients.

Limitations of HLH-2004 criteria in distinguishing malignancy-associated hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is characterized by dysregulated immune activation.  Primary HLH involves hereditary deficits in cytotoxic lymphocytes while secondary HLH is triggered by extrinsic factors. The HLH-2004 criteria are widely used for clinical diagnosis, yet their specificity for HLH or their ability to differentiate primary from secondary disease is unclear, potentially leading to inappropriate treatment. We describe several cases where fulfillment of HLH-2004 criteria obscured the diagnoses of underlying malignancies and delayed curative management. These issues are remedied without waiting for genetic testing results through an alternative diagnostic approach using flow cytometry-based immunologic assays and a thorough investigation for malignancy.

Viral surveillance using PCR during treatment of AML and ALL

BACKGROUND

While viral surveillance of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus using PCR is routine in patients undergoing hematopoetic stem cell transplant and solid organ transplant, the utility in the nontransplant pediatric leukemia population is unknown. Our institution screens patients with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) for viral DNAemia by PCR as part of clinical care.

PROCEDURE

This retrospective chart review included patients treated for newly diagnosed or relapsed AML or ALL between April 2010 and September 2014. We retrieved data for viral PCR screening, detection and quantification, duration of positivity, and prophylaxis or treatment.

RESULTS

One hundred eleven patients were included in analyses. Forty (36.0%) had at least one blood PCR positive for EBV, CMV, or adenovirus. Patients with ALL had significantly higher rates of persistent viral detection and treatment than those with AML (P < 0.02, P < 0.01, respectively). International patients had significantly higher rates of viral detection (P < 0.01), persistence (P < 0.01), any treatment (P < 0.03), and antiviral treatment (P < 0.01); 16.9% of patients who received intravenous immunoglobulin (IVIG) prophylactically had viral detection compared to 63% of patients who did not receive prophylactic IVIG (P = 0.0008).

CONCLUSIONS

Patients with ALL were more susceptible than those with AML to viral reactivation that was persistent or resulted in treatment. Patients with relapsed ALL, refractory ALL, or infantile ALL are most likely to benefit from asymptomatic screening for CMV and adenovirus. International patients are at higher risk for reactivation and may merit screening. EBV reactivation was not significant and does not warrant screening.

Use of Genome Engineering to Create Patient Specific MLL Translocations in Primary Human Hematopoietic Stem and Progenitor Cells

One of the challenging questions in cancer biology is how a normal cell transforms into a cancer cell. There is strong evidence that specific chromosomal translocations are a key element in this transformation process. Our studies focus on understanding the developmental mechanism by which a normal stem or progenitor cell transforms into leukemia. Here we used engineered nucleases to induce simultaneous specific double strand breaks in the MLL gene and two different known translocation partners (AF4 and AF9), which resulted in specific chromosomal translocations in K562 cells as well as primary hematopoietic stem and progenitor cells (HSPCs). The initiation of a specific MLL translocation in a small number of HSPCs likely mimics the leukemia-initiating event that occurs in patients. In our studies, the creation of specific MLL translocations in CD34+ cells was not sufficient to transform cells in vitro. Rather, a variety of fates was observed for translocation positive cells including cell loss over time, a transient proliferative advantage followed by loss of the clone, or a persistent proliferative advantage. These studies highlight the application of genome engineering tools in primary human HSPCs to induce and prospectively study the consequences of initiating translocation events in leukemia pathogenesis.

Anti-N-methyl-D-aspartate receptor encephalitis: early treatment is beneficial

Anti-N-methyl-D-aspartate receptor antibody has been associated with a severe stereotypic form of subacute encephalitis, often found in women with ovarian teratoma. Reported here is the diagnosis of anti-N-methyl-D-aspartate receptor encephalitis in a 5-year-old girl who presented with subacute encephalopathy and movement disorder without evidence of malignancy. Early diagnosis and treatment with immune globulin and steroids resulted in near-complete recovery.