ALBERT

Description: Early T-precursor (ETP) ALL is a recently described poor prognostic sub-group of childhood T-ALL identified by a distinctive gene expression profile and immunophenotype (CD1a-, CD5 weak, CD8- and presence of myeloid or stem cell markers). It accounts for around 12% of T-ALL and is associated with a poor outcome in retrospective US and Italian studies with a 5 year event-free survival (EFS) of less than 50% on historical treatment protocols. We sought to determine the outcome for this sub-group on a contemporary MRD stratified treatment protocol, UKALL 2003. As full immunophenotype data was not collected centrally, individual centres were asked to provide individual patient data retrospectively. Of 387 T-ALL cases in the trial, immunophenotype data to classify ETP status was not available for 148 patients. Of the remaining 239 cases, 35 (15%) were classified as definite/probable (CD8 and 1a neg with stem cell or myeloid antigen expression) and 17 (7%) as possible (CD8 neg and stem cell or myeloid antigen expression, 1a not available) ETP. The definite, probable and possible ETP groups had similar patient characteristics and outcomes and have, therefore, been analysed together. Compared to those without an ETP phenotype, ETP patients were more likely to present with a low (

Description: In this study, we characterized nuclear factor κB (NF-κB) subunit DNA binding in chronic lymphocytic leukemia (CLL) samples and demonstrated heterogeneity in basal and inducible NF-κB. However, all cases showed higher basal NF-κB than normal B cells. Subunit analysis revealed DNA binding of p50, Rel A, and c-Rel in primary CLL cells, and Rel A DNA binding was associated with in vitro survival (P = .01) with high white cell count (P = .01) and shorter lymphocyte doubling time (P = .01). NF-κB induction after in vitro stimulation with anti-IgM was associated with increased in vitro survival (P 〈 .001) and expression of the signaling molecule ZAP-70 (P = .003). Prompted by these data, we evaluated the novel parthenolide analog, LC-1, in 54 CLL patient samples. LC-1 induced apoptosis in all the samples tested with a mean LD50 of 2.8 μM after 24 hours; normal B and T cells were significantly more resistant to its apoptotic effects (P 〈 .001). Apoptosis was preceded by a marked loss of NF-κB DNA binding and sensitivity to LC-1 correlated with basal Rel A DNA binding (P = .03, r2 = 0.15). Furthermore, Rel A DNA binding was inversely correlated with sensitivity to fludarabine (P = .001, r2 = 0.3), implicating Rel A in fludarabine resistance. Taken together, these data indicate that Rel A represents an excellent therapeutic target for this incurable disease.

Description: Internal tandem duplication (ITD) of the FMS-like receptor tyrosine kinase 3 (FLT3) is the most frequently reported molecular defect in Acute Myeloid Leukaemia (AML), occurring in 25–30% of cases. ITD mutations of FLT3 constitutively phosphorylate the receptor and are associated with a poor prognosis. It has been postulated that FLT3 mutations play a critical role in the pathogenesis of AML. FLT3/ITD is a known client of the molecular chaperone heat shock protein 90 (Hsp90). Using 17-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of Hsp90, we studied the in-vitro effects of Hsp90 inhibition in FLT3/ITD positive AML. A murine myeloid IL-3 dependent cell line (32D) was transfected with FLT3/ITD and FLT3/WT (wild type). The FLT3/ITD mutation resulted in constitutive autophosphorylation of the receptor and IL-3 independence of the cell line. 17-AAG specifically induced cell death by apoptosis in the FLT3/ITD cells in a dose dependent fashion (IC50 300nM). The effect of 17-AAG was most marked in the FLT3/ITD cells in the absence of IL-3. The introduction of IL-3 rescued the cells from inhibition suggesting that the IL-3 intracellular signalling pathway remained intact after treatment. 17-AAG synergised with cytosine arabinoside (Ara C) in the FLT3/ITD cells (combination index 0.65). Immunoprecipitation of Hsp90 in primary AML cells demonstrated co-precipitation of mutant phosphorylated FLT3 in cells that were FLT3/ITD positive. FLT3 does not, however, appear to be chaperoned by Hsp90 in blasts from patients with unmutated FLT3. Consequently we studied diagnostic samples from 20 AML patients in which cells were treated with serial concentrations of 17-AAG. Cell killing was significantly increased (P= 0.016) in samples that were FLT3/ITD positive (mean IC50 0.62± 0.50 μM, n=10) compared with FLT3/ITD negative (mean IC50 1.22± 0.47 μM, n=10). Exposure of FLT3/ITD positive AML blasts to 17-AAG resulted in rapid dephosphorylation of phosphorylated FLT3 in the majority of samples. This was not seen in FLT3/ITD negative samples. The dephosphorylation of mutant FLT3 was associated with an upregulation of the stress responsive chaperones Hsp70 and BiP (GRP78) suggesting that this response is via the direct inhibition of Hsp90. Both the STAT5 pathway and the phosphatidylinositol 3-kinase/Akt pathway have been shown to be important in signalling downstream of mutant FLT3. We have demonstrated dephosphorylation of STAT5 in tandem with dephosphorylation of FLT3/ITD following treatment of cells with 17-AAG. In addition, Hsp90 inhibition also results in downregulation of Akt protein kinase. This suggests that the apoptosis seen following exposure to 17-AAG is a direct result of disrupted signalling via inhibition of mutant FLT3. Our results provide evidence that inhibition of the chaperone protein Hsp90 may have a role in the therapy of FLT3/ITD positive AML. We have also shown Ara C to synergise with Hsp90 inhibition and would suggest that this may be a feasible clinical approach for this difficult disease.

Description: Background Overall survival (OS) for teenagers and young adults (TYA) aged 15-24 years (yrs) with acute lymphoblastic leukaemia (ALL) is inferior to OS for children. In the UK, five-year OS for children up to 14 years with ALL is 89%, falling to 69% for 15-19 yr olds and 52% for 20-24 yr olds (O'Hara et al, National Cancer Intelligence Network, 2013). Both disease biology and choice of protocol are likely to be important in explaining these differences. However, lower rates of inclusion into clinical trials with increasing age may also be a significant factor. In the UK 3 national paediatric and adult ALL trials were open to recruitment between 1997-2006 (table 1). In 2006 the upper age eligibility criteria for UKALL2003 was increased from 18 to 24 yrs and the lower age limit of UKALL XII was correspondingly increased to reflect emerging evidence that TYA have improved outcomes when treated on paediatric protocols. Aims 1. To examine trial accrual rates (AR) by age over a ten year period (1997-2006) to three UK national ALL trials. 2. To determine the influence of amending the age eligibility criteria for UKALL2003 on TYA accrual Methods ALL incidence figures for patients aged 1-39 yrs during the study period of 1997-2006 were obtained from a national cancer registry. Incidence data was classified according to the morphology-based coding specifically for TYA (Birch et al, BJC, 2002). Accrual rates (AR) were expressed as the ratio of patients entered onto trials during the same time period compared to incidence cases. Descriptive statistics were applied for an observational dataset where sample size or incidence cases cannot be controlled (Fern et al. BJC, 2008). We obtained a further incidence data set for cases diagnosed in 2007 and 2008 to examine the impact of age eligibility amendments in 2006 and 2008 to UKALL2003. Results ALL was diagnosed in 4,579 patients aged 1-39 yrs between 1997-2006, 2,767 were under 10 yrs. The figure shows the proportion of newly diagnosed ALL patients entering trials 1997-2006. Red arrows show age eligibility criteria of the trials. 65% of all patients were enrolled onto one of the 3 trials. AR were highest for under 10's (71.5%), declining to 55.2% for 15-16 yr olds, 43.4% for 17-18 yr olds and 40% for those aged 21-24 yrs. The amendments to age inclusion criteria for UKALL2003 and UKALL XII improved AR for 17-18 yr olds to a level equivalent to AR for 15-16 yr olds. AR for 19-20 yr olds also improved to 62.5%. However, recruitment of 21-24 year olds did not change. During 1997-2006 three quarters of 17-18 yr olds recruited to trials were enrolled onto UKALLXII. After protocol amendments, three quarters of 17-18 yrs were recruited to the paediatric trial. Conclusions We have shown a decline in trial accrual with increasing age for teenagers and young adults with ALL despite the availability of national trials spanning the age range being available during the time period studied. Due to close cooperation between adult and paediatric trial management groups, major changes were made to age eligibility criteria for both paediatric and adult trials, following increasing evidence that TYA have better outcomes when treated on paediatric protocols. We have shown an increased accrual of older teenagers to ALL trials in the UK following these changes. No improvements were observed for 21-24 year olds. However, this age group were only eligible for UKALL 2003 during the last year of our analysis. This approach to trial eligibility design may serve as a model for future trials, both in ALL and other cancers. Disclosures: No relevant conflicts of interest to declare.

Description: Minimal residual disease (MRD) testing is vital to risk assignment in acute lymphoblastic leukaemia (ALL). Quantification of patient-specific rearrangements of immunoglobulin and T-cell receptor (Ig/TCR) genes is the most standardised method in current use. Recent studies demonstrated that deletion in the IKZF1 gene is common and is prognostic of poor outcome. IKZF1 targets could offer potential for MRD monitoring in BCR-ABLnegative (neg) ALL. The 5' and 3' break points of this deletion are highly conserved, making it possible to design a universal PCR assay to amplify the fusion genomic sequence created by the deletion. With the initial aim of developing an MRD assay we studied the incidence of IKZF1 Δ 4-7 in 161 consecutive patients enrolled on the on-going adult ALL trial UKALL14, aged 25-59 years. We carried out PCR using breakpoint-specific primers designed as close as possible to the breakpoint. In order to ensure that the screening PCR enabled sensitive detection of the deletions, serial dilution of a positive control SUP-B15 cell line diluted into non-tumoral DNA was analysed. IKZF1 Δ 4-7 could be detected with a sensitivity of at least 10-4 (0.01%). PCR bands could be readily allocated to “strong” or “weak” on visual inspection; all PCR positive signals were confirmed as IKZF1 Δ 4-7 by Sanger sequencing of the PCR products and the breakpoints mapped. The frequency of the deletion in the total population studied was 80/161 (50%); 23/35 (66%) in the BCR-ABL positive (pos) subgroup and strikingly 57/126 (45%) in the BCR-ABLneg subgroup. The high rate of IKZF1 Δ 4-7 in the BCR-ABLneg patients was unexpected, being approximately double the reported incidence BCR-ABLneg adults. Real time quantitative (RQ)-PCR analyses to investigate the suitability of IKZF1 quantitation as the basis for an MRD assay was performed on 26 BCR-ABLneg cases, selected only on the basis of availability of follow-up material. Assays were assessed using the same criteria applied by EuroMRD for Ig/TCR quantification. On that basis, “limited testing” of PCR amplifications at the 10-2 (1%) and 10-4(0.01%) dilution points was performed on all 26 samples. To our surprise, only 5 samples gave acceptable data to qualify for a quantitative MRD assay. Notably, all the 21 cases that failed “limited testing” had yielded a weak PCR signal on initial screening, suggesting the PCR assay have detected intragenic deletions restricted to minor subclones. Although subclonal IKZF1 gene alterations are well described, the apparent high frequency of these events in our cohort (21/26 tested for RQ-PCR assay) was surprising. To further analyse this, we performed MRD-based genomic quantification of all 26 diagnostic specimens using SUP-B15 dilution series. The percentage of ALL cells bearing IKZF1 Δ 4-7 in the putative 21 subclonal cases was 90% in the putative 5 major clonal cases. In total, 82% of BCR-ABLneg cases gave a weak PCR band at initial screening, suggesting that most of the Δ 4-7 in BCR-ABLneg adult ALL are subclonal. In the 5 cases where a quantifiable IKZF1 Δ 4-7-based MRD assay could be developed, MRD analysis was performed on 12 follow-up samples and sensitivity and quantitative range of at least 10-4 (0.01%) and 5×10-4 (0.05%) were obtained, respectively. These parameters compare favourably with the performance of standard Ig/TCR assays. Notably in one sample MRD could only be quantified by the IKZF1 deletion approach (level= 7.79E-05, ∼ 0.008%). IKZF1 lesions are not leukaemia-initiating events, hence the stability of this alteration during the history of ALL is not clear. To address this, 14 diagnosis and relapse paired samples were analysed. Three different patterns emerged: in 5 cases the IKZF1 Δ 4-7 at diagnosis was preserved at relapse; in 3 cases the lesion was newly acquired at relapse; and in 3 cases the deletion was lost at relapse, notably all these 3 cases had showed a weak PCR signal, suggesting the deletion which was lost at relapse was subclonal at diagnosis. Theoretically this observation suggests that IKZF1deletion-based MRD monitoring carries a risk of missing a resurgent clone. In conclusion, IKZF1 Δ 4-7 can provide highly sensitive MRD assays and could be a potential candidate to add to the repertoire of currently available MRD markers. However, we have shown limited applicability due to many IKZF1 deletions occurring in putative subclones. The stability of these deletions in major clones remains to be determined. Disclosures: No relevant conflicts of interest to declare.

Description: B-cell chronic lymphocytic leukaemia (CLL) cells have a differential capacity to signal through the B-cell receptor (BCR) following ligation with anti-IgM. This difference in signaling capacity has been suggested to contribute to the clinical disparity between the two subsets. However, as there appears to be no obvious correlation between response to IgM ligation and surface IgM expression, CD20 expression or CD79b expression it may be that the differential signaling response in these two distinct subsets is not caused by the BCR itself. In this study we investigated the expression of the BCR co-receptor complex (CD19, CD21 and CD81) in a cohort of CLL patients (n = 60) in order to determine whether expression of the co-receptor was associated with known CLL prognostic markers; IgVH gene mutational status, ZAP-70 and CD38 expression. In addition, we examined the relationship between co-receptor expression and the capacity of CLL cells to respond to anti-IgM cross-linking of the BCR. CLL samples showed significantly lower expression of both CD19 and CD21 when compared to normal B-lymphocytes (P

Description: Introduction Treatment outcomes for teenage and young adult (TYA) patients with Acute Lymphoblastic Leukaemia (ALL) lag behind those of younger patients when treated on equivalent protocols, with higher rates of toxicity and relapse reported for those aged 〉10 years. Outcomes of relapsed ALL are poor so more accurate identification of those destined to relapse is required. Whilst minimal residual disease (MRD) is a powerful tool to predict those at low risk and in whom treatment can be de-escalated, improved strategies are required for early identification of high risk patients. This study aimed to determine if the morphological early response assessment could be used as a predictor of relapse in TYA patients with ALL. Methods All patients treated on the national prospective UKALL2003 trial aged 10 - 24 years who had not relapsed by day 35 (i.e. could potentially have treatment escalated) were included in the study. Early response in patients aged 〉10 years was defined as percentage of blasts by morphology at day 8: rapid early responders had ≤ 25% blasts and slow early responders 〉25% blasts. We analysed the following patient characteristics which were previously associated with differential outcomes: age at diagnosis, presenting white cell count, rapid or slow early response (RER or SER); MRD status at day 28; immunophenotype (B/T/other) and cytogenetic risk group (high risk, good risk, poor risk, T-ALL, other). Cox regression was used to assess the association of these factors with time to relapse and logistic regression (LR) was used to assess their association with relapse by the end of treatment (EOT: 2.5 years for girls and 3.5 years for boys). Using backwards selection (cut off for inclusion: p=0.1) a multivariable LR model was established and a receiver operating characteristic curve (ROC) was used to assess how well it could predict relapse before the EOT. Results 820 consecutive patients were included in the analysis of whom 597 were aged 10 - 15 years and 223 were aged 16 - 24 years. 332 patients were classified as MRD high risk and 184 as SER on the basis of morphology. RER was significantly associated with a reduced risk of relapse even after adjustment for other factors including MRD, age, WBC and risk status (Hazard Ratio (HR) 0.64 (95% CI 0.42 - 0.97, p

Description: Introduction: As the majority of children and young people now survive acute lymphoblastic leukaemia (ALL), the challenge has shifted to minimising treatment related toxicity. Osteonecrosis is one of the most serious complications of treatment, and can result in significant long term morbidity. In UKALL2003, which recruited patients between Oct 1, 2003 and June 30, 2011, all patients received dexamethasone 6mg/m2 for 29 days during induction and again for 5 days each month during maintenance in combination with Vincristine. Standard and intermediate risk patients were randomised to 1 or 2 delayed intensifications, each of which contained dexamethasone 10mg/m2 for 14 days in an alternate week schedule. Aim: To report the prevalence, management and long term outcomes of patients who developed osteonecrosis among 3126 patients aged 1-24 years old entered into UKALL2003. Methods: Patients with reported bone toxicity were identified by the central trials unit, which also provided information regarding age, sex, ethnicity and treatment. A questionnaire for each patient was sent to the relevant primary treatment centres (n=40) requesting information on patient demographics, diagnosis, management and outcomes of patients with osteonecrosis. Each primary treatment centre was also asked for details of previously unreported patients known to have osteonecrosis. Statistical analysis was undertaken using Chi-squared tests to identify significant differences in the prevalence of osteonecrosis according to age, sex, ethnicity, and treatment. Percentages were calculated as simple percentages. Results: We received an 83% response rate from primary treatment centres. 153 patients (5%) were reported as having developed osteonecrosis at some point after the start of treatment for ALL (including relapse therapy or stem cell transplant if required (n=5)), of which 38 were previously unreported to the clinical trials unit. Age demonstrated the strongest association with risk of osteonecrosis (p=0.01). Of patients aged 10 years at diagnosis of ALL (with a total of 839 patients aged 〉10 years in UKALL2003). There were 130 patients aged〉18 years at diagnosis in UKALL2003, and of these, 4 required a hip replacement. With a median follow up of 70 months (range 27-124 months), 57 patients were reported to have no long term effects, 59 patients had minimal disability (able to carry out activities of daily living), 16 had significant disability, and 5 patients required a wheelchair at the time of response. 9 patients died from disease relapse, progression of ALL, sepsis or acute graft versus host disease. Outcome information was not available for a further 9 patients. Conclusion: This work highlights the impact of osteonecrosis as a cause of considerable morbidity for patients treated for ALL, with important implications for quality of life. Further, this work confirms that the greatest impact is on those aged over 10 years at diagnosis, with 1 in 30 patients in this group requiring hip replacement. Better strategies to monitor for and manage this condition are required to reduce the incidence, whilst maintaining overall and event free survival. Disclosures No relevant conflicts of interest to declare.

Description: In the donor versus no donor analysis of the UKALL12/E2993 trial in adult acute lymphoblastic leukaemia (ALL), there was a significant improvement in overall survival (OS) and reduction in relapse in the donor arm. However the OS benefit did not extend to older patients in whom myeloablative allogeneic hematopoietic cell transplant (alloHCT) related mortality was 35% at 2 years and outweighed the reduction in relapse risk. The overall outcome of older patients in this trial was poor, with patients 〉40 and 50 years having 23% and 15% 5 year survival respectively. In our current UK National Cancer Research Institute UKALL14 study all patients 〉40 years in CR, regardless of Philadelphia (Ph+) status and other high risk factors, are considered "high risk" and recommended a reduced intensity conditioned (RIC) alloHCT with a matched sibling (sib) or 8/8 matched unrelated donor (MUD) after a 2 course induction and high dose methotrexate. The primary endpoint is event free survival (EFS). We report here the early outcome of 88 patients with at least day 100 follow up (FU) (median FU 18 months) who received RICalloHCT on trial. Conditioning was with fludarabine 30mg/m2 d -6 to -2, melphalan 140 mg/m2 d -2 and alemtuzumab 30mg d -2 to-1 (MUD) or d-1 (sib). Graft versus host disease (GVHD) prophylaxis was ciclosporin A only. Nine patients did not receive alemtuzumab as per protocol. Multilineage chimerism (MC) and minimal residual disease (MRD) were assessed 3 monthly post alloHSCT. Escalating doses of donor lymphocyte infusions (DLI) were given for T-cell mixed chimerism or MRD, starting dose 1 x 106 CD3 cells/kg, escalating by half log increments every 3 months. Of 511 registered patients, 306 were 〉40 years old; 127 of those have completed RIC allograft, 88 of whom have sufficient FU to report. Median age was 51.5 years (range 41 to 64). Donor was sib in 24 and MUD in 64 patients, respectively. Median WBC at diagnosis was 7 x 109/l (0.6-557). Forty one of 77 (53%) evaluable patients had high risk cytogenetics, 22 (25%) were Ph+. Twelve of 56 (21%) with MRD data were MRD +ve pre-alloHCT. Post-alloHCT, myeloid engraftment occurred in 86/88 patients at a median of 13 days, 2 had missing data. Acute graft versus host disease (GVHD) occurred at grade 1 in 30 patients (34%) and grade 2-3 in 8 patients (9%). Thirty patients developed chronic GVHD (34% of 87/88 patients surviving to D100), 13 limited and 17 extensive. Of 12 patients who suffered transplant-related mortality (TRM), 6 died of infection (one post-transplant lymphoproliferative disease), 4 of organ toxicity and 2 of GVHD. TRM was not associated with age or donor type. Sixteen patients relapsed at a median time of 317 days (range 110-1034). Of those, 9 (of 15 with data) had high risk cytogenetics (EFS, p=0.38) and 6 (of 11 with data) were MRD +ve pre-alloHCT (EFS, HR 3.35, p=0.047). Twenty seven patients in total received 67 DLI (median maximum dose 3 x 106 CD3 cells/kg): 15 for mixed chimerism, 4 for rising MRD and 8 for both. Five patients (19%) developed post-DLI GVHD at grade 1 (n=4) and grade 2 (n=1). MC data is available for 36 patients receiving alemtuzumab and is shown in figure 1 where dark grey bars represent full and light grey bars mixed chimerism, respectively. DLI are denoted by black dashes. Mixed chimerism was seen in 22 of 36 patients (61%) who received alemtuzumab and so far 26 of 36 have achieved full donor chimerism (median 9 months), 10 after DLI (38%). Figure 2 shows Kaplan Meier curves of OS 76% (64-84, 95% CI) and EFS 68% (55-77)at 18 months. This is the first prospective study of RIC alloHCT in older adults with ALL; these early results demonstrate its feasibility within a large, multicentre trial. T-cell mixed chimerism was common at 1st MC assessment but early data indicate that conversion to full donor chimerism with DLI is a safe and realistic possibility. The impact of mixed chimerism (and pre-emptive DLI) on relapse remain to be evaluated. Severe GVHD and TRM were relatively low, such that the EFS of chemotherapy then RIC alloHCT, albeit with short-term FU, may be higher than expected for chemotherapy alone in this age group. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Copland: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Fielding:Amgen: Consultancy, Honoraria.