Buck, Georgina

Abstract Genomic classification has improved risk assignment of pediatric, but not adult B-lineage acute lymphoblastic leukemia (B-ALL). The international UKALLXII/ECOG-ACRIN E2993 (#NCT00002514) trial accrued 1229 adolescent/adult patients with BCR-ABL1− B-ALL (aged 14 to 65 years). Although 93% of patients achieved remission, 41% relapsed at a median of 13 months (range, 28 days to 12 years). Five-year overall survival (OS) was 42% (95% confidence interval, 39, 44). Transcriptome sequencing, gene expression profiling, cytogenetics, and fusion polymerase chain reaction enabled genomic subtyping of 282 patient samples, of which 264 were eligible for trial, accounting for 64.5% of E2993 patients. Among patients with outcome data, 29.5% with favorable outcomes (5-year OS 65% to 80%) were deemed standard risk (DUX4-rearranged [9.2%], ETV6-RUNX1/-like [2.3%], TCF3-PBX1 [6.9%], PAX5 P80R [4.1%], high-hyperdiploid [6.9%]); 50.2% had high-risk genotypes with 5-year OS of 0% to 27% (Ph-like [21.2%], KMT2A-AFF1 [12%], low-hypodiploid/near-haploid [14.3%], BCL2/MYC-rearranged [2.8%]); 20.3% had intermediate-risk genotypes with 5-year OS of 33% to 45% (PAX5alt [12.4%], ZNF384/-like [5.1%], MEF2D-rearranged [2.8%]). IKZF1 alterations occurred in 86% of Ph-like, and TP53 mutations in patients who were low-hypodiploid (54%) and BCL2/MYC-rearranged (33%) but were not independently associated with outcome. Of patients considered high risk based on presenting age and white blood cell count, 40% harbored subtype-defining genetic alterations associated with standard- or intermediate-risk outcomes. We identified distinct immunophenotypic features for DUX4-rearranged, PAX5 P80R, ZNF384-R/-like, and Ph-like genotypes. These data in a large adult B-ALL cohort treated with a non–risk-adapted approach on a single trial show the prognostic importance of genomic analyses, which may translate into future therapeutic benefits.

Summary Late relapse [>3 years from complete remission (CR)] in acute lymphoblastic leukaemia (ALL), is unusual. Data from the MRC UKALLXII/ECOG E2993 trial are presented to evaluate the incidence and characteristics of late relapse in adult ALL. Of 1,909 patients, 1,752 (92%) achieved CR and among these 757 (43·2%) relapsed; 691 (91·3%) within three years and 66 (8·7%) beyond. Among these 66 patients, median time to relapse was 47 (37–144) months. Relapse beyond three years occurred in 3·8% of all who achieved CR. The cumulative risk of relapse was 40%, 43% and 45% at three, five and ten years respectively. Out of the 1 752 patients who achieved CR, 11·7% underwent autologous and 40·6% allogeneic transplant, while in CR1. Of the autologous patients, 43·2% relapsed early and 3·4% relapsed late. However, among the allogeneic patients, 13·2% relapsed early and only 1·3% late. The five‐year overall survival from relapse was 5·8% and 20% in the early and late relapse patients respectively. In conclusion, late relapse in adults with ALL is not uncommon, and is associated with better outcome after relapse compared to early relapse.

Abstract The International ALL trial, conducted jointly by the MRC in the UK and ECOG in the US (UKALL XII/E2993), recruited 1929 patients between 1993 and 2006. All patients aged 16 to 64 years with newly diagnosed ALL, received the identical two phases of induction therapy. Patients with an HLA-identical sibling were assigned to a sibling allogeneic transplant and those who were Ph-positive could also get an unrelated-donor transplant. Patients who did not have a donor were to be randomized between a single autologous transplant, after conditioning with etoposide/total body irradiation, versus consolidation/maintenance therapy for 2.5 years. Following randomization, but prior to receiving the assigned or randomized therapy, all patients received intensification with 3 cycles of high-dose methotrexate. After excluding patients assigned to an allogeneic transplant, 1028 patients were eligible for randomization but, as in other major transplant studies, only 457 were randomized. The rationale underlying the randomization was based on the fact that protracted consolidation/maintenance therapy in adults, extrapolated from the pediatric experience, had never been prospectively evaluated in the era of intensive chemotherapy. Given that the mortality from autotransplant is not higher than chemotherapy (Goldstone et al. Blood. 2008), it was postulated that if a single autologous transplant is at least as good as standard protracted chemotherapy that may make it the preferable option, except possibly in females in whom fertility may be an issue. The overall survival and the event-free survival were significantly superior among the chemotherapy patients (p = .05) as previously reported (Goldstone et al. Blood. 2008). Because the literature contains reports suggesting a trend in favor of autologous transplantation in some patients with ALL (Dhédiu et al. Leukemia, 2006), an analysis was performed to see if any subgroup of patients could be identified in whom: 1. chemotherapy may not be superior to autologous transplant and 2. autologous transplant may be superior. The table lists a detailed analysis of overall survival looking at various age groups, B- versus T-lineage, the rapidity with which a complete remission was achieved –after phase I or only after phase II of induction. Detailed analysis was also performed by cytogenetics looking at those with standard risk versus those with high risk abnormalities [ t(9;22), t(4;11), t(8;14)] and low hypodiploidy/near triploidy or a complex karyotype (Moorman et al. Blood. 2007)]. In all groups, the chemotherapy group was at least as efficacious as the autograft group, and in some was even significantly superior to autologous transplantation. There is no evidence that other risk factors, such as relapse rate or treatment-related mortality, influenced these overall survival data. In addition, the tests for heterogeneity were not significant across any group. In conclusion, the overall survival was longer in patients randomized to chemotherapy, although the superiority was not statistically significant in most of the groups. There is no clinical indication for autologous transplantation at any age and particularly this should not be considered for patients over age 50, those with high-risk cytogenetics or T-lineage, and late remitters, for whom it might appear most attractive. Overall Survival (OS) at 5 years in 457 Randomized Patients Chemo Auto Subgroups n OS n OS P (log rank) Age (years) < 20 50 58% 43 46% > 0.1 20–29 61 52% 70 43% > 0.1 30–39 46 39% 46 32% > 0.1 40–49 38 31% 35 31% > 0.1 50 + 33 38% 35 31% > 0.1 B-lineage 169 46% 158 35% 0.03 T-lineage 45 54% 54 49% > 0.1 Time to CR phase I 193 48% 190 41% 0.1 phase II 26 36% 29 19% 0.08 Cytogenetics standard-risk 109 51% 122 44% > 0.1 high-risk 29 23% 27 7% 0.02

Abstract Abstract 493 The International MRC UKALL XII/ECOG E2993 trial for adults with newly diagnosed acute lymphoblastic leukemia (ALL) recruited 1,914 patients to the main part of the trial from 1995 up to its closure in 2006, of whom 100 were over the age of 55 years (median 57, range 55–65). Beginning in 2003 (MRC) or 2004 (ECOG), patients with Philadelphia chromosome positive (Ph+ve) disease were entered into an Imatinib sub-study. We report here baseline characteristics, treatment course and outcomes, and discuss implications for future management strategies. Direct comparison of the 100 patients over 55 yrs with 1,814 under 55 yrs showed that the groups are comparable for gender, immunophenotype and white cell count but there is an indication that more elderly patients had Ph+ve disease (28% aged ≥55 vs 17% aged <55 of those entered before the start of the Imatinib trial; p=0.02). All patients in this trial received a 2 stage induction regimen, consisting of Daunorubicin, Vincristine, Asparaginase and Steroid followed by Cyclophosphamide, Cytarabine, 6-Mercaptopurine and Methotrexate. CNS prophylaxis with IT Methotrexate and Cytarabine was given during both phases. There was a randomisation to autograft or chemotherapy, but only a small number of patients in this age group were randomised (13 autograft and 13 consolidation chemotherapy). Outcomes Complete remission (CR) rate, event-free survival (EFS) and overall survival (OS) were all worse in the over 55 age group, and even after achieving CR, the 5-year OS rate was reduced. There were more infections in phase I induction (67% vs 45%, p<0.0001) and more deaths during induction chemotherapy (18% vs 4% p<0.0001). Excluding those who died in induction, 47% had drug dose reductions in phase I or phase II vs 27% <55 yrs (P=0.0006). Of these, Asparaginase was the most common in those aged ≥55 years, usually due to hepatotoxicity. Age p-value <55 vs ≥55 <55 ≥55 Number 1814 100 CR No v Yes p<0.0001 No 131 (7%) 27 (27%) No (died in induction) 70 (4%) 18 (18%) No (but survived induction) 61 (3%) 9 (9%) Yes 1641 (90%) 70 (70%) Unknown 42 (2%) 3 (3%) Deaths 1112/1814 (61%) 78/100 (78%) Relapses 750/1683 (45%) 36/73 (49%) Overall survival at 5 years (95% CI) 41% (38–43%) 21% (12–29%) p<0.0001 Event free survival at 5 years (95% CI) 37% (34–39%) 19% (10–27%) p<0.0001 Relapse free survival at 5 years (95% CI) 50% (48–53%) 38% (25–52%) p=0.08 Overall survival at 5 years (95% CI) in those who achieved CR 44% (41–46%) 30% (18–41%) p=0.03 In those patients aged ≥55 years, baseline factors causing a significantly worse 5-yr EFS were Ph-positivity (0% vs 23%, p=0.005), unfavourable vs standard cytogenetic risk (7% vs 26%, p=0.02) and a presenting WCC >50 × 109/l (0% vs 25% for WCC between 10 and 49.9 × 109/l and 23% for WCC <10 × 109/l, p=0.003). Infection during induction chemotherapy predicted for worse EFS; this was especially significant in those who had infection in both phases of induction (6% vs 38%, p=0.007). In those patients who received chemotherapy and were not transplanted, the differences in outcome were smaller: 5-yr OS 25% in ≥55 years vs 38% in <55 years (p=0.06), 5-yr EFS 22% vs 32% (p>0.1). Conclusion Older adults fared significantly worse than younger adults both in terms of achieving an initial CR and long-term survival. This difference cannot be explained solely by a difference in disease characteristics, and the marked increase in infection and deaths during induction reflect the inability of many older patients to tolerate the intensive level of treatment. This is also supported by the large numbers of drug omissions or dose reductions seen. Our data show that this inability to tolerate induction chemotherapy is a major contributor to the poor outcomes seen in this age group. The less marked differences between age groups when transplant patients are excluded, indicates the significant mortality associated with these procedures in older patients. Alternative approaches to consider in this group include less intensive induction with a steroid and vinca alkaloid combination, in conjunction with targeted therapies (eg Rituximab in B-lineage CD20+ disease, Imatinib Mesylate in Ph+ disease). Even amongst those patients who do achieve CR however, the long-term outcome is worse. Reduced intensity allografts may play a role in carefully selected patients in this age group, and the emerging use of MRD monitoring may also assist in selecting patients for more or less intensive approaches. Disclosures: McMillan: EUSA: Honoraria. Goldstone: Roche: Honoraria, Speakers Bureau.

Abstract This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and the Medical Research Counsel, United Kingdom, and supported in part by Public Health Service Grants CA180820, CA180794, CA180790, CA189859, CA180853, CA180791, and from the National Cancer Institute, National Institutes of Health and the Department of Health and Human Services. Its content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute. Background: Late relapse in acute leukemia is considered a relatively rare event. Patients with acute myeloid leukemia (AML) are often considered cured of the disease at 3 years, but information regarding adult acute lymphoblastic leukemia (ALL) patients is scarce. Data are presented from one of the largest prospective adult ALL studies, the MRC UKALLXII/ECOG E2993, to evaluate the rate and characteristics of late relapse in ALL. For this purpose, late relapse was defined, arbitrarily, as relapse 3 years post achievement of complete remission (CR) and very late relapse was defined as relapse > 5 years from CR. Methods: The UKALLXII/ECOG E2993 was an international ALL trial conducted jointly by the MRC in the United Kingdom and ECOG in the United States. All patients received identical induction therapy, followed by central nervous system prophylaxis. Patients with a sibling donor (or a matched unrelated donor in Philadelophia-chromosome-positive ALL) were assigned to receive an allogeneic hematopoietic stem cell transplant (HSCT); all others were randomized to undergo an autologous transplant or protracted standard consolidation/ maintenance therapy. The study accrued 2109 patients from 1993 to 2008. Following relapse, patients were followed for survival. For this report only patients registered before the tyrosine kinase inhibitors era are included in the analysis. Results: 1518 study patients were eligible for this analysis, 1208 (79.6%) Philadelphia-chromosome negative (Ph-neg) and 267 (17.5%) Philadelphia-chromosome positive (Ph-pos). 1381 (91%) of the patients achieved CR; 93% of the Ph-neg and 82% of the Ph-pos. 572 patients (37.7%) underwent allogeneic HSCT. The median duration of follow-up of patients who achieved CR was 10 years. Among the 1381 patients who achieved CR, 626 (45.3%) had a documented relapse; 566 (90.4%) relapsed within 3 years of CR and 60 (9.6%) relapsed beyond 3 years ('late relapse') (Figure 1). Among these 60 patients, 18(2.9%) relapsed after 5 years ('very late relapse'). Table. Patients n CR All relapses Relapses< 3 years Relapses≥ 3 years Relapses≥ 5 years All patients 1518 1381 (91%) 626 (45.3%) 566 (90.4%) 60 (9.6%) 18 (2.9%) Ph-neg 1208 (79.6%) 1123 (93%) 485 (40.1%) 429 (88.5%) 56 (11.5%) 17 (3.5%) Ph-pos 268 (17.5%) 219 (82%) 124 (56.6%) 122 (98.4%) 2 (1.6%) 1 (0.8%) Relapse beyond 3 years occurred in 4.3% of all who achieved CR, in 5% of Ph-neg and 0.01% of Ph-pos patients. Among the 60 late relapses, the median time to relapse was 46 months. 61.7% of the late-relapse patients were males, median age was 32 years, 88.3% were B-lineage ALL and the median white cell count at diagnosis was 6000/ul. 56.7% were in cytogenetic standard risk, 8.3% at high risk and the data of 35% are unknown. The median survival for the late relapse patients was longer than for those who relapsed within 3 years. The overall survival (OS) of the 56 Ph-neg patients who relapsed beyond 3 years is shown in Fig 2. Table.Relapse > 3 yearsRelapse > 3 yearsMedian survival from relapse (months)5.411.23-year OS from relapse6.5%29%5-year OS from relapse5.6%19% Conclusions: Late relapses in adults with Ph-neg ALL are not uncommon. About 10% of relapses occur beyond 3 years and 4.3% of all ALL patients who achieved a CR can expect to have a late relapse. These data are in contrast to AML where only 1% of patients relapse beyond 3 years (Watts JM et al, 2014). Most of the late relapse patients were at standard risk and appeared to have a relatively favorable outcome post relapse. Patients with ALL, particularly those who are Ph-neg, cannot be considered as cured at 3 years and need to be closely followed. Figure 1. Time to relapse of Ph-pos and Ph-neg ALL Figure 1. Time to relapse of Ph-pos and Ph-neg ALL Figure 2. Survival from relapse for Ph-neg patients who relapsed after 3 years from CR. Figure 2. Survival from relapse for Ph-neg patients who relapsed after 3 years from CR. Disclosures Rowe: Amgen: Consultancy; BioSight Ltd.: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx Ltd.: Consultancy. Douer:Gilead: Consultancy.

Abstract Abstract 524 The International UKALLXII/E2993 trial enrolled 2091 pts with newly diagnosed adult ALL between 1993 and 2006. Patients received 2 months of combination induction chemotherapy followed by an intensification course of high dose methotrexate and L-asparaginase after which pts were randomized to autologous hematopoietic stem cell transplant (HSCT) or consolidation and maintenance chemotherapy. Patients <55 years of age with a matched sibling donor were assigned myeloablative allogeneic HSCT (Goldstone, et al, Blood 2008; 111:1827). Here we report a detailed analysis of 1,229 pts from this trial with B-ALL, excluding Philadelphia-chromosome-positive patients. The median age was 30 years (range 14–65) and 59% were male. The median WBC was 9.2×109/L (range 0.1–930) and 73% of pts had a WBC <30 × 109/L. CNS involvement was present in 4% of pts at diagnosis. Comprehensive centralized immunophenotyping was performed in 372 of the 409 (91%) ECOG pts enrolled and initial analysis demonstrated pro-B/pre-pre-B in 17%, early pre-B in 52%, pre-B in 14%, either early pre-B or pre-B in 6%, mature B in 2% and B-lineage, not otherwise specified, in 9%. Outcomes were similar between patients with immunophenotyping data and those without. The complete remission (CR) rate was 93% and there were 4% induction deaths. The overall survival (OS), event-free survival (EFS), relapse risk (RR) and non-relapse mortality (NRM) at 5 years for the overall group is shown in the table. There were no significant differences in CR rate, OS, EFS, RR or NRM for the immunophenotypic subgroups. There was better OS and EFS with less relapse and similar risk of NRM for pts randomized to chemotherapy as compared with autologous HSCT (Figure 1). In the matched sibling donor-no donor comparison, OS and EFS were improved, RR was less and NRM was higher in the donor group (Figure 2). Cytogenetic analysis confirmed that patients with t(4;11) (n=77, 8% total), t(8;14) (n=19, 2% total), a complex karyotype (≥5 abnormalities in the absence of an established chromosomal abnormality) (n=38, 5% total), or low hypoploidy/near triploidy (n=41, 5% total) had an inferior OS and patients with high hyperdiploidy had a superior OS when compared to other patients. In conclusion, this is the largest series of B-ALL in uniformly treated adults ever reported and confirms the superior outcome of patients randomized to chemotherapy as compared with autologous HSCT and shows that patients with a matched sibling donor have an improved survival over patients without a donor. No difference in CR rates or outcome was noted for patients with different immunophenotypic subtypes of B-ALL. Future improvements in outcome of pts with B-ALL will rely on the addition of new agents such as B cell monoclonal antibodies and improvements in allogeneic HCT.Table.Outcomes at 5 years of follow-upnCR rate (%)OSEFSRRNRMOverall12299342375021Pro-B/pre-pre-B639236345421Early pre-B/pre-B2689340345421Age ≤ 35 years746 (61%)9653454516Chi square p<0.0001<0.0001<0.0001<0.0001<0.0001Age >35 years483 (39%)8932265930Randomized to autologous HSCT15735316610Log rank p0.030.010.01NSRandomized to chemotherapy1694742558Matched sib donor34452483032Chi square p0.050.03<0.001<0.001No Donor47445415510Values are % except n and p values. CR=complete remission, OS=overall survival, EFS=event-free survival, RR=relapse risk, NRM=non-relapse mortality NS=not significant. The p values represent the difference between age groups for the first comparison, randomized to autologous HSCT versus chemotherapy for the second comparison and between matched sibling donor and no donor for the third comparison. Overall survival by randomized allocation at 10 years Overall survival by donor availability at 10 years Disclosures: No relevant conflicts of interest to declare.

Abstract Acute lymphoblastic leukemia (ALL) has a high relapse rate in adults. While the biology of the patient may be responsible for the marked difference in survival seen in comparison to children, variable adherence to complex chemotherapy regimens may also play a role. However, there is very little understanding about the risk factors for delays in therapy and the impact of delays on survival. To study delays in newly diagnosed adult ALL patients, we conducted an observational study using data from ECOG 2993/ MRC_UKALLXII (Rowe, Blood 2005). We analyzed Ph- patients who started intensification after documented complete remission (CR). A long delay (LD) was defined as > 98 days from start of induction to start of intensification (IS), which was >2 weeks delay beyond the 84 days recommended per protocol. A Very Long Delay (VLD) was defined as a >4 weeks delay. Of 2109 patients enrolled, 1247 patients met inclusion criteria for analysis. Of note, 435 Ph- patients who achieved CR after induction but did not proceed to intensification were excluded. In univariate analysis, female sex (p<0.001), Black race (p=0.01), and older age (p<0.001) were associated with increased odds of LD. During induction presence of infection (p=0.01), dose reductions (p=0.001), duration of neutropenia (p=0.007), thrombocytopenia (p<0.001), and hospitalization duration (p<0.001) were associated with LD. In multivariate regression, age, female sex, dose reduction, Black race, and hospitalization duration were significantly associated with LD and VLD (Table I). At 2 years after diagnosis, 801/1247 (64.2%) patients were alive. Of the surviving patients, 181 (22.5%) had VLD, and 620 (77.4%), had delay <4 weeks, p=0.073. Of the alloHCT patients, 333 were alive: 57/333 (17%) had VLD, and 276/333 (83%) had been delayed <4 weeks (p=0.036). As of July 2014, 687/1247 (55%) patients have died, with a median time to death from start of intensification of 13.3 months (range 0.8-231). Survival analysis was stratified by post-remission therapy, with living patients censored at date last seen. Patients who received myeloablative allogeneic HCT (allo HCT) had poorer overall survival from start of intensification (OS-IS) and event free survival (EFS-IS) after LD or VLD. While OS-IS and EFS-IS were significantly worse for alloHCT patients after VLD (p=0.02 and p=0.03) respectively, survival was not worse for non-transplant patients after VLD (p=0.24 and p=0.10) (Figure I). In a multivariate Cox regression, adjusting for other high-risk disease features (age, cell lineage, and white cell count at diagnosis), patients who underwent allo HCT had significantly worse OS-IS (HR 1.4, p=0.02) and EFS-IS (HR 1.4, p=0.02) after experiencing VLD compared to alloHCT patients who experienced <4 weeks delay. When evaluating OS and EFS from diagnosis, VLD was still associated with poorer OS (HR 1.34, p=0.04) and EFS (HR 1.34, p=0.03). There was no difference in OS or EFS in patients who received non-transplant post-remission therapy based on delay. In a comprehensive analysis of the largest adult ALL study ever reported, we identified significant risk factors predictive of LD and VLD (>2 and >4 weeks beyond mandatory rest period). Our findings highlighted that patients were delayed because of chemotherapy toxicity and also identified healthcare disparities. VLD was associated with poorer OS and EFS in patients undergoing alloHCT, but not in patients undergoing non-transplant post remission therapy. Further studies are planned to prospectively identify patient barriers to on-schedule treatment with a goal of earlier intervention. The ability to better predict and intervene on risk factors for delay can improve adherence to protocol and optimize long-term survival. Table I: Multivariate Regression for LD and VLD Risk Factors Variable Odds Ratio 95% Confidence Interval p-value Days in the hospital Phase I Induction 1.01 1.00-1.02 0.04 Duration of Thrombocytopenia, Phase I 1.02 1.01-1.03 0.001 Age by Decade 1.2 1.08-1.31 <0.001 Reduced Dose in Induction 1.54 1.08-2.22 0.019 Sex, Female 1.56 1.22-2.0 <0.001 Race, Black 3.4 1.41-7.96 0.006 Figure 1 Figure 1. p=0.023 Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 169 The Philadelphia positive (Ph+) arm of the international adult acute lymphoblastic leukaemia (ALL) trial UKALL12/ECOG2993 opened in 1993 and is the largest single study of patients with Ph+ ALL, with a total of 441 participants. The first cohort of study patients was treated prior to Imatinib (N=266 “Pre Imatinib“) with 2 phases of induction therapy given over 2 months followed by matched sibling or unrelated donor myeloablative allogeneic haematopoietic stem cell transplant (alloHSCT) whenever possible. The treatment protocol and outcome for these patients has been published (Fielding et al, Blood 2009). Beginning March 2003, a second cohort of study patients had Imatinib 600mg daily added, as a consolidation block after the second induction chemotherapy, (N=86, “Late Imatinib”). From late 2005, a final cohort within the trial were given Imatinib earlier, in conjunction with the second phase of induction (N=89, “Early Imatinib”). Patients in both Imatinib cohorts resumed the drug for a further 2 years following alloHSCT, if tolerated. If alloHSCT was not possible, Imatinib was permitted for 2 years, with maintenance. The trial closed to recruitment in December 2006 (USA) and October 2008 (UK). All except 8 patients have now completed therapy. An earlier analysis of these data did not indicate a clear long-term advantage to receiving Imatinib. We now report 3-year follow-up, which shows large outcome differences between the 3 groups. There were no pre-existing differences between the 3 cohorts in terms of gender, presenting white blood cell counts and presence of central nervous system disease at diagnosis. However, the Pre-Imatinib cohort was younger than the two Imatinib cohorts, due to an increase in the upper age limit for study entry. Percentage complete remission (CR) rates and survival of induction therapy are shown in table 1. The total CR rate for the imatinib cohorts was significantly higher than for the pre-imatinib cohort (p=0.004). Table 1 Pre-Imatinib With Imatinib N=266 Total With Imatinib N=175 Part 1 Late Imatinib N=86 Part 2 Early Imatinib N=89 Died in induction<d56 5 5 3 7 Survived induction but never achieved remission 13 3 5 1 Total not achieving CR 18 8 8 8 CR on protocol induction 67 77 73 80 Total CR rate (includes those achieving remission later than post induction) 82 92 92 92 Pre- Imatinib, only 28% of patients went on to receive alloHSCT as per protocol. With any Imatinib, 44% of patients received alloHSCT as per protocol. Survival outcomes of patients in the 3 cohorts are shown in the table 2. Overall survival (OS), event free survival (EFS) and relapse free survival (RFS) are all at 3 years with 95% confidence intervals (CI) shown in brackets. The P values are for two comparisons - ** denotes the comparison between patients receiving any Imatinib and patients receiving none and ^ denotes the comparison between the Early and Late Imatinib cohorts. Table 2 Pre-Imatinib With Imatinib Total With Imatinib Part 1 Late Imatinib Part 2 Early Imatinib % OS (95% CI) (see also Figure 1) 25 (20–30) 42 (34–49) 34 (24–44) 48 (36–60) p=0.0001** p=0.05^ % EFS (95% CI) 19 (14–24) 36 (29–44) 29 (19–38) 45 (34–56) p=0.0001** p=0.04^ % RFS (95% CI) 36 (28–43) 54 (45–63) 45 (33–57) 62 (50–75) p=0.0001** p=0.02^ Figure 1 Three-year OS for patients who received per protocol alloHSCT was 59% vs. 28% (with no plateau on the curve) for those who did not receive alloHSCT as per protocol. By comparison, pre-imatinib, 5 year OS was 40% for transplanted- and 19% for non-transplanted patients. Hence, the extent to which Imatinib without subsequent alloHSCT can improve the outcome for adult Ph+ ALL is not yet clear. Figure 1. Three-year OS for patients who received per protocol alloHSCT was 59% vs. 28% (with no plateau on the curve) for those who did not receive alloHSCT as per protocol. By comparison, pre-imatinib, 5 year OS was 40% for transplanted- and 19% for non-transplanted patients. Hence, the extent to which Imatinib without subsequent alloHSCT can improve the outcome for adult Ph+ ALL is not yet clear. In conclusion, receiving any Imatinib during induction for Ph+ ALL significantly enhances CR rate and increase alloHSCT rate. This translates into a highly significant EFS, OS and RFS advantage to receiving Imatinib during therapy. An earlier start to Imatinib is significantly better than a later start. Though comparisons between study cohorts are not randomised, the large differences seen are unlikely to be explained by factors other than treatment. There can be no basis for omitting Imatinib from the initial therapy of adult patients with Ph+ ALL. However, our data show that the best outcome is seen when patients receive Imatinib followed by myeloablative alloHSCT, where nearly 60% of such patients survive 3 years from diagnosis. Disclosures: Goldstone: Roche: Honoraria, Speakers Bureau.

Adults with acute lymphoblastic leukemia (ALL) have a poorer prognosis than children due to a high risk of relapse. One explanation may be variable adherence to dose‐intense chemotherapy. However, little is known about risk factors for delays in therapy and their impact on survival. We conducted an analysis of ECOG 2993/UKALLXII trial to study delays in postremission chemotherapy in adults with newly diagnosed ALL. Logistic regression was used to identify risk factors for a very long delay (VLD, >4 weeks) in start of intensification therapy. Cox regression was used to evaluate the impact of delays on overall survival (OS) and event‐free survival (EFS). We evaluated 1076 Philadelphia chromosome negative (Ph−) patients who completed induction chemotherapy, achieved complete remission, and started intensification. Factors independently associated with VLD included duration of hospitalization (odds ratio [OR] = 1.2, P < 0.001) during Phase I; thrombocytopenia during Phase I (OR = 1.16, P = 0.004) or Phase II (OR 1.13, P = 0.001); chemotherapy dose reductions during Induction Phase I (OR = 1.72, P < 0.014); female sex (OR = 1.53, P = 0.010); Black (OR = 3.24, P = 0.003) and Asian (OR = 2.26, P = 0.021) race; and increasing age (OR = 1.31, P < 0.001). In multivariate Cox regression, patients who underwent allogeneic stem cell transplant (alloHCT) had significantly worse OS (HR 1.4, P = 0.03) and EFS (HR 1.4, P = 0.02) after experiencing a VLD compared to alloHCT patients who experienced ≤4 weeks delay. Specific populations (female, older, Black, and Asian patients) were more likely to experience delays in chemotherapy, as were those with significant toxicity during induction. VLDs in therapy negatively affected outcomes in patients undergoing allografting. Am. J. Hematol. 91:1107–1112, 2016. © 2016 Wiley Periodicals, Inc.

Key Points Imatinib improves outcomes for adults with Ph+ ALL at least in part by facilitating allogeneic stem cell transplant. Allogeneic hematopoietic stem cell transplant is not dispensible in Ph+ ALL in the imatinib era.