Bella Patel

UKALLXII/ECOG2993: addition of imatinib to a standard treatment regimen enhances long-term outcomes in Philadelphia positive acute lymphoblastic leukemia

The Philadelphia chromosome positive arm of the UKALLXII/ECOG2993 study for adult acute lymphoblastic leukemia (ALL) enrolled 266 patients between 1993 and 2003 (pre-imatinib cohort). In 2003 imatinib was introduced as a single-agent course following induction (N = 86, late imatinib). In 2005 imatinib was added to the second phase of induction (N = 89, early imatinib). The complete remission (CR) rate was 92% in the imatinib cohort vs 82% in the preimatinib cohort (P = .004). At 4 years, the overall survival (OS) of all patients in the imatinib cohort was 38% vs 22% in the preimatinib cohort (P = .003). The magnitude of the difference between the preimatinib and imatinib cohorts in event-free survival (EFS), OS, and relapse-free survival (RFS) seen in univariate analysis was even greater in the multivariate analysis. In the preimatinib cohort, 31% of those starting treatment achieved hematopoietic stem cell transplant (alloHSCT) compared with 46% in the imatinib cohort. A Cox multivariate analysis taking alloHSCT into account showed a modest additional benefit to imatinib (hazard ratio for EFS = 0.64, 95% confidence interval 0.44-0.93, P = .02), but no significant benefit for OS and RFS. Adding imatinib to standard therapy improves CR rate and long-term OS for adults with ALL. A proportion of the OS benefit derives from the fact that imatinib facilitates alloHSCT. This trial was registered at clinicaltrials.gov as NCT00002514.

Minimal residual disease is a significant predictor of treatment failure in non T-lineage adult acute lymphoblastic leukaemia: final results of the international trial UKALL XII/ECOG2993

The predictive value of molecular minimal residual disease (MRD) monitoring using polymerase chain reaction amplification of clone‐specific immunoglobulin or T‐cell Receptor rearrangements was analysed in 161 patients with non T‐lineage Philadelphia‐negative acute lymphoblastic leukaemia (ALL) participating in the UK arm of the international ALL trial UKALL XII/Eastern Cooperative Oncology Group (ECOG) 2993. MRD positivity (≥10−4) in patients treated with chemotherapy alone was associated with significantly shorter relapse‐free survival (RFS) at several time‐points during the first year of therapy. MRD status best discriminated outcome after phase 2 induction, when the relative risk of relapse was 8·95 (2·85–28·09)‐fold higher in MRD‐positive (≥10−4) patients and the 5‐year RFS 15% [95% confidence interval (CI) 0–40%] compared to 71% (56–85%) in MRD‐negative (<10−4) patients (P = 0·0002) When MRD was detected prior to autologous stem cell transplantation (SCT), a significantly higher rate of treatment failure was observed [5‐year RFS 25% (CI 0–55%) vs. 77% (95% CI 54–100%) in MRD‐negative/<10−4, P = 0·01] whereas in recipients of allogeneic‐SCT in first complete remission, MRD positivity pre‐transplant did not adversely affect outcome. These data provide a rationale for introducing MRD‐based risk stratification in future studies for the delineation of those at significant risk of treatment failure in whom intensification of therapy should be evaluated.

IGH@ Translocations, CRLF2 Deregulation, and Microdeletions in Adolescents and Adults With Acute Lymphoblastic Leukemia

PURPOSE To determine the prevalence and prognostic impact of significant acute lymphoblastic leukemia (ALL) -related genes: CRLF2 deregulation (CRLF2-d), IGH@ translocations (IGH@-t), and deletions of CDKN2A/B, IKZF1, PAX5, ETV6, RB1, BTG1, and EBF1 in adolescents and adults. PATIENTS AND METHODS The cohort comprised 454 patients (age 15 to 60 years old) treated on the multicenter United Kingdom Acute Lymphoblastic Leukaemia Trial XII/Eastern Cooperative Oncology Group 2993 trial (UKALLXII/ECOG2993) with Philadelphia-negative B-cell precursor ALL. Fluorescent in situ hybridization and multiplex ligation-dependent probe amplification were used to detect these genetic alterations. RESULTS Twenty patients (5%) had CRLF2-d (P2RY8-CRLF2, n = 7; IGH@-CRLF2, n = 13), and 36 patients (8%) harbored an IGH@-t with a different partner gene. There was little overlap between IGH@-t, CRLF2-d, and established chromosomal abnormalities. Deletions of CDKN2A/B, IKZF1, PAX5, ETV6, RB1, BTG1, or EBF1 were prevalent with 101 (33%) of 304 patients harboring one and 102 (33%) harboring two or more alterations, occurring with varying frequency in all cytogenetic subgroups. The 5-year event-free survival, relapse-free survival (RFS), and overall survival (OS) rates for the whole cohort were 40%, 55%, and 43%, respectively. Patients with CRLF2-d, IGH@-t, and IKZF1 deletions were associated with an inferior outcome in univariate but not multivariate analysis. In particular, CRLF2-d patients had a lower RFS compared with other patients (30%), whereas those with IGH@-t or IKZF1 deletions had a lower OS (27% and 35%, respectively). CONCLUSION CRLF2-d and IGH@-t represent distinct subtypes of adolescent and adult ALL. Deletions of key B-cell differentiation and cell cycle control genes are highly prevalent but vary in frequency by cytogenetic subgroup. CRLF2-d, IGH@-t, and IKZF1 deletions are associated with poor outcome in adolescent and adult ALL.

Notch-1 Mutations Are Secondary Events in Some Patients with T-Cell Acute Lymphoblastic Leukemia

Purpose: Activating Notch-1 mutations are frequent in T-cell acute lymphoblastic leukemia (T-ALL), occurring in >50% of patients. In murine models of T-ALL, Notch-1 activation can both directly initiate leukemia and cooperate secondarily to other primary events. Whether acquisition of Notch-1 mutations is an early initiating event or a secondary event in the pathogenesis of human T-ALL is unclear. Experimental Design: We used denaturing high-performance liquid chromatography, sequencing, and fragment analysis to analyze Notch-1 mutational status and mutant level in 62 patients at presentation as well as 16 matched presentation-relapse samples. Results: We detected Notch-1 mutations in 47 patients (76%). Seven of these were low-level mutations (quantified at ≤10%), despite high blast counts, suggesting that they were acquired as a secondary event in a subclone. Of 16 matched presentation-relapse samples studied, 7 were wild-type at both presentation and relapse. Five of nine mutant-positive patients at presentation relapsed with the same mutation(s) at the same high level. Four patients had evidence of a change in mutant at relapse. One lost a PEST mutation and became wild-type. Two others lost mutations at relapse but acquired different mutations, despite unchanged T-cell receptor rearrangements, suggesting that the latter event predated the acquisition of the Notch-1 mutation. One relapsed with a secondary T-cell leukemia and different Notch mutation. Conclusions: These results suggest that Notch-1 mutations can sometimes be acquired as secondary events in leukemogenesis and must be used cautiously as solitary minimal residual disease markers.

High incidence of avascular necrosis in adolescents with acute lymphoblastic leukaemia: a UKALL XII analysis

Avascular necrosis (AVN) is a serious complication of acute lymphoblastic leukaemia (ALL) therapy. Little is known of the scope and magnitude of this problem among adults with ALL. We analysed the incidence and risk factors for AVN in 1053 patients on the UKALLXII/ECOG2993 study. AVN affected 99 joints in 42 patients at a median of 2.2 years post-diagnosis, giving a crude incidence rate of 4.0%. Statistically significant risk factors for the development of AVN were age and treatment with chemotherapy. Patients receiving prolonged chemotherapy without stem cell transplant were at significantly greater risk of developing AVN than stem cell transplant recipients (P<0.00005). The actuarial incidence of AVN was 29% at 10 years in patients <20 years old compared to 8% at 10 years in those >20 years old; P=0.0004; odds ratio 0.28 (95% CI=0.14–0.56).

Favorable outcomes with alemtuzumab-conditioned unrelated donor stem cell transplantation in adults with high-risk Philadelphia chromosome-negative acute lymphoblastic leukemia in first complete remission

T-cell depletion is generally believed to effectively prevent graft-versus-host disease (GVHD), yet to impose an adverse effect on disease-free survival that eventually affects overall survival of leukemia patients undergoing allogeneic hematopoietic stem cell transplantation. In this study, however, Dr. Patel and co-workers demonstrate that T-cell-depleted hematopoietic stem cell transplantation from unrelated donors can result in good overall survival and low non-relapse mortality for adults with high-risk acute lymphoblastic leukemia in first complete remission. Background Approximately 40% of adults with Philadelphia chromosome-negative acute lymphoblastic leukemia achieve long-term survival following unrelated donor hematopoietic stem cell transplantation in first complete remission but severe graft-versus-host disease remains a problem affecting survival. Although T-cell depletion abrogates graft-versus-host disease, the impact on disease-free survival in acute lymphoblastic leukemia is not known. Design and Methods We analyzed the outcome of 48 adults (median age 26 years) with high-risk, Philadelphia-chromosome-negative acute lymphoblastic leukemia undergoing T-cell depleted unrelated donor-hematopoietic stem cell transplantation (67% 10 of 10 loci matched) in first complete remission reported to the British Society of Blood and Marrow Transplantation Registry from 1993 to 2005. Results T-cell depletion was carried out by in vivo alemtuzumab administration. Additional, ex vivo T-cell depletion was performed in 21% of patients. Overall survival, disease-free survival and non-relapse mortality rates at 5 years were 61% (95% CI 46–75), 59% (95% CI 45–74) and 13% (95% CI 3–25), respectively. The incidences of grades II–IV and III–IV acute graft-versus-host disease were 27% (95% CI 16–44) and 10% (95% CI 4–25), respectively. The actuarial estimate of extensive chronic graft-versus-host disease at 5 years was 22% (95%CI 13–38). High-risk cytogenetics at diagnosis was associated with a lower 5-year overall survival (47% (95% CI 27–71) vs. 68% (95% CI 44–84), p=0.045). Conclusions T-cell depleted hematopoietic stem cell transplantation from unrelated donors can result in good overall survival and low non-relapse mortality for adults with high-risk acute lymphoblastic leukemia in first complete remission and merits prospective evaluation.

Human mesenchymal stromal cells deliver systemic oncolytic measles virus to treat acute lymphoblastic leukemia in the presence of humoral immunity

Clinical trials of oncolytic attenuated measles virus (MV) are ongoing, but successful systemic delivery in immune individuals remains a major challenge. We demonstrated high-titer anti-MV antibody in 16 adults with acute lymphoblastic leukemia (ALL) following treatments including numerous immunosuppressive drugs. To resolve this challenge, human bone marrow-derived mesenchymal stromal cells (BM-MSCs) were used to efficiently deliver MV in a systemic xenograft model of precursor B-lineage-ALL. BM-MSCs were successfully loaded with MV ex vivo, and MV was amplified intracellularly, without toxicity. Live cell confocal imaging demonstrated a viral hand-off between BM-MSCs and ALL targets in the presence of antibody. In a murine model of disseminated ALL, successful MV treatment (judged by bioluminescence quantification and survival) was completely abrogated by passive immunization with high-titer human anti-MV antibody. Importantly, no such abrogation was seen in immunized mice receiving MV delivered by BM-MSCs. These data support the use of BM-MSCs as cellular carriers for MV in patients with ALL.

Differential Cytopathology and Kinetics of Measles Oncolysis in Two Primary B-cell Malignancies Provides Mechanistic Insights

Clinical trials using vaccine measles virus (MV) as anticancer therapy are already underway. We compared the oncolytic potential of MV in two B-cell malignancies; adult acute lymphoblastic leukemia (ALL, an aggressive leukemia) and chronic lymphocytic leukemia (CLL, an indolent leukemia overexpressing Bcl-2) using patient-derived material. In vitro, distinct cytopathological effects were observed between MV-infected primary ALL and CLL cells, with large multinucleated syncytia forming in ALL cultures compared to minimal cell-to-cell fusion in infected CLL cells. Cell viability and immunoblotting studies confirmed rapid cell death in MV-infected ALL cultures and slower MV oncolysis of CLL cells. In cell lines, overexpression of Bcl-2 diminished MV-induced cell death providing a possible mechanism for the slower kinetic of MV oncolysis in CLL. In vivo, intratumoral MV treatment of established subcutaneous ALL xenografts had striking antitumor activity leading to complete resolution of all tumors. The antitumor activity of MV was also evident in disseminated ALL xenograft models. In summary, both ALL and CLL are targets for MV-mediated lysis albeit with different kinetics. The marked sensitivity of both primary ALL cells and ALL xenografts to MV oncolysis highlights the tremendous potential of MV as a novel replicating-virus therapy for adult ALL.

Genomic analyses identify recurrent MEF2D fusions in acute lymphoblastic leukaemia.

Chromosomal rearrangements are initiating events in acute lymphoblastic leukaemia (ALL). Here using RNA sequencing of 560 ALL cases, we identify rearrangements between MEF2D (myocyte enhancer factor 2D) and five genes (BCL9, CSF1R, DAZAP1, HNRNPUL1 and SS18) in 22 B progenitor ALL (B-ALL) cases with a distinct gene expression profile, the most common of which is MEF2D-BCL9. Examination of an extended cohort of 1,164 B-ALL cases identified 30 cases with MEF2D rearrangements, which include an additional fusion partner, FOXJ2; thus, MEF2D-rearranged cases comprise 5.3% of cases lacking recurring alterations. MEF2D-rearranged ALL is characterized by a distinct immunophenotype, DNA copy number alterations at the rearrangement sites, older diagnosis age and poor outcome. The rearrangements result in enhanced MEF2D transcriptional activity, lymphoid transformation, activation of HDAC9 expression and sensitive to histone deacetylase inhibitor treatment. Thus, MEF2D-rearranged ALL represents a distinct form of high-risk leukaemia, for which new therapeutic approaches should be considered.

Pegylated-asparaginase during induction therapy for adult acute lymphoblastic leukaemia: toxicity data from the UKALL14 trial.

Safety and efficacy data on pegylated asparaginase (PEG-ASP) in adult acute lymphoblastic leukaemia (ALL) induction regimens are limited. The UK National Cancer Research Institute UKALL14 trial NCT01085617 prospectively evaluated the tolerability of 1000 IU/m2 PEG-ASP administered on days 4 and 18 as part of a five-drug induction regimen in adults aged 25–65 years with de novo ALL. Median age was 46.5 years. Sixteen of the 90 patients (median age 56 years) suffered treatment-related mortality during initial induction therapy. Eight of the 16 died of sepsis in combination with hepatotoxicity. Age and Philadelphia (Ph) status were independent variables predicting induction death >40 versus ⩽40 years, odds ratio (OR) 18.5 (2.02–169.0), P=0.01; Ph− versus Ph+ disease, OR 13.60 (3.52–52.36), P<0.001. Of the 74 patients who did not die, 37 (50.0%) experienced at least one grade 3/4 PEG-ASP-related adverse event, most commonly hepatotoxicity (36.5%, n=27). A single dose of PEG-ASP achieved trough therapeutic enzyme levels in 42/49 (86%) of the patients tested. Although PEG-ASP delivered prolonged asparaginase activity in adults, it was difficult to administer safely as part of the UKALL14 intensive multiagent regimen to those aged >40 years. It proved extremely toxic in patients with Ph+ ALL, possibly owing to interaction with imatinib.