Citations

AbstractTopotecan (TPT) is a topoisomerase I (topo I) poison that has shown promising antineoplastic activity in solid tumors and acute leukemia. In the present study, a band depletion assay was used to evaluate the ability of TPT to stabilize topo I-DNA adducts in human leukemia cell lines and in clinical leukemia samples ex vivo. This assay showed that 50% of the cellular topo I in HL-60 human myelomonocytic leukemia cells became covalently bound to DNA at an extracellular TPT concentration of 4 μmol/L. In contrast, in 13 clinical specimens of human leukemia harvested before treatment of patients with TPT, the TPT concentration required to stabilize 50% of the cellular topo I in topo I-DNA complexes ranged from 3 to greater than 100 μmol/L (median, 30 μmol/L). Flow microfluorimetry showed that cellular TPT accumulation varied over only a twofold range and failed to provide evidence for transport-mediated resistance in the clinical samples. These observations raise the possibility that formation of topo I-DNA adducts is diminished in many specimens of refractory/relapsed acute leukemia by a mechanism that might alter topo I sensitivity to TPT.

Abstract Abstract 4048 Background: The plasma cell labeling index (PCLI) is measured as the percentage of bone marrow plasma cells (PC) in the S phase of the cell cycle and provides an estimate of the proliferative capacity of malignant PC in multiple myeloma (MM). The International Myeloma Working Group (IMWG) uniform response criteria measure the monoclonal (M) protein and serum free light chain (FLC) assay to evaluate clinical response. An elevated PCLI is an established adverse prognostic risk factor for survival, however it is unknown if the PCLI response to therapy offers further prognostic value. Methods: Data from 176 newly diagnosed MM patients from 1985 to 2005 were collected from the Mayo Clinic dysproteinemia database. Inclusion criteria for the study required a minimum initial PCLI of 0.5% and a subsequent PCLI 4 months after initiation of therapy. Baseline and subsequent serum M-protein, progression date, and overall survival were recorded. Clinical responses were assessed by the IMWG uniform response criteria. The association of PCLI response and treatment response (CR, VGPR, or PR) was assessed univariately. Overall survival based on PCLI response, M-spike reduction, and treatment response by IMWG criteria was estimated using the Kaplan-Meier method. Results: The median overall survival (OS) was 47 months (range: 4 – 165). Ninety-four patients (53%) demonstrated a ≥60% reduction in PCLI after initial therapy (responders) and this conferred a significant OS advantage of 51 months vs. 34 months (P<0.01; Figure 1) compared to those who achieved <60% PCLI reduction (non-responders) after initial therapy. The median PCLI percent difference following 4 months of therapy was -67% (+/− 137%; range: -100 to 953%). When patients were stratified into high (PCLI of ≥3%), intermediate (PCLI ≥1%) and low (PCLI <1%) risk groups, OS was significantly improved in the high and intermediate PCLI groups if they achieved ≥60% reduction in PCLI after initial therapy, 31 vs. 7 months (P<0.0022; Figure 2) and 63 vs. 25 months (P<0.0005; Figure 3), respectively. As observed in prior studies, patients with PCLI of ≥3% at diagnosis had shorter overall survival (17 months) when compared to patients with an initial PCLI of <1% (61 months; P < 0.0001). Of the 94 responders, 39% (n=37) did not achieve a response to therapy as measured by M-protein. Thirteen patients (14%) had no measurable serum M-protein at baseline. Conversely, 35% (n=31) of patients that responded by M-protein criteria did not achieve a PCLI response. In patients who achieved CR/PR after 4 months of therapy, the median PCLI reduction was 83.7% vs. 22.5% (P <0.0004) compared to patients with stable disease (not meeting criteria for CR or PR) or progressive disease (as specified by IMWG response criteria). This reflects a significant reduction in disease burden and as expected, median OS was better in the CR/PR group (53 vs. 31 months, P <0.0016). Conclusion: Our study demonstrates that the degree of PCLI reduction after therapy is important in predicting overall survival and response to therapy. This is an important finding in the current setting of effective MM treatment options, whereby patients who do not achieve an adequate response as defined as ≥60% reduction in PCLI in our study, may require change in therapy. Our data confirm that reduction of M-protein is an important surrogate endpoint, as patients who achieved PR and CR lived significantly longer. A significant portion of individuals 39% had a measurable response by PCLI that was not detected by M-protein. Further studies are needed to evaluate the predictive value of the addition a criterion that looks at reduction in proliferative rate as measured by PCLI or other methods such as flow cytometry. Disclosures: Greipp: Mayo Clinic: Patents & Royalties.

Abstract Abstract 4990 Background: Although there have been improvements in 5-year overall survival (OS) rates among patients with AL amyloidosis over the past decades, OS is still poor, and death rates within the first 3–6 months after diagnosis have not changed significantly. This retrospective study was performed to identify risk factors for and causes of death during the first 90 days following diagnosis of AL amyloidosis. Method: From July 2002 to April 2009, 301 patients with a diagnosis of AL amyloidosis who were seen at Mayo Clinic within 30 days of diagnosis were identified from the dysproteinemia database. The 100 who died within 90 days were the focus of our study. The other 201 who were alive beyond 90 days were used as a comparator group. Outside physician offices were contacted to obtain further information pertaining to treatment and cause of death for our study group. Results: Of the 100 patients with early death, median age at diagnosis was 63.7 years (range: 34.7–89.4). 25 patients were diagnosed with concurrent multiple myeloma (MM) based on MM-specific end-organ damage. Overall, the number of patients with 2, 3 and 4 organs (cardiac, renal, nerve or liver) involved with amyloidosis was 37, 15 and 4, respectively. Using the cardiac biomarker staging system, 78% of 46 evaluable patients were stage III at diagnosis followed by 22% stage II and no stage I. Table 1 describes the characteristics of the studied population. Amyloid-related deaths were identified in 61 patients with the most common cause being cardiac arrest or sudden death (33%) followed by end-organ failure (24%). Treatment was started in 50% of patients; 34% received no treatment; and no treatment information was available for the remainder. OS was 54.5 days in patients who received treatment as compared to 7.5 days in those who received no treatment (p<0.0001); outcomes were similar in the group in whom no treatment information was available and those patients who were known to have received treatment. Melphalan with dexamethasone was the most common treatment (21%) and was associated with improved OS compared to other treatments including novel agents (57 vs. 26 days, p=0.003). Outcomes were no different if the patients had received novel therapies, but numbers were small. When compared to patients who lived for more than 90 days from their diagnosis, patients with early mortality had higher median intraventricular septum (IVS) (15 vs. 13 mm, p<0.0001), lower ejection fraction (EF) (50 vs. 64%, p<0.0001), and higher troponin-T (0.125 vs. 0.01 ng/ml, p<0.0001) and NT-proBNP (9020 vs. 1292 pg/ml, p<0.0001). We also found that patients who died within 90 days of their diagnosis had significantly higher plasma cell labeling index (PCLI), uric acid, beta-2 microglobulin, involved free light chain (FLC) and creatinine. Conclusion: This study highlights the characteristics of patients who died within 90 days of diagnosis of AL amyloidosis. The majority of patients died from arrhythmia and organ failure. This implies that other interventions aside from treatment of the underlying plasma cell (PC) disorder will likely be required to change the early outcomes of this disease. Disclosures: Lacy: Celgene: Research Funding. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Dispenzieri:Celgene: Honoraria, Research Funding; Binding Site: Honoraria.

Abstract Introduction In 2 large phase 3 trials of patients (pts) with relapsed or refractory (R/R) CLL/SLL, single-agent ibrutinib (ibr) was superior to ofatumumab (ofa) (RESONATE; Byrd. NEJM 2013) and ibr + BR was superior to placebo + BR (HELIOS; Chanan-Khan. ASCO 2015). Both studies evaluated ibr in different pt populations with different relevant comparators (eg, ofa in pts who had relapsed following prior anti-CD20-based chemoimmunotherapy [CIT] and/or with del17p, and BR in pts eligible for CIT). In the absence of head-to-head evaluations of single-agent ibr vs BR or single-agent ibr vs ibr + BR, indirect comparisons can be used for hypothesis testing by potentially providing insights on the relative efficacy of treatments. As such, an indirect comparative analysis of data from RESONATE and HELIOS was performed. Recognizing biases inherent in cross-trial comparisons, including lack of randomization across trials and consequent differences in distributions of important confounding variables (eg, pt characteristics, prognostic factors), we used pt-level data from both studies to risk adjust for confounders using accepted multivariate statistical approaches. Methods In RESONATE, pts received 420 mg oral ibr daily until disease progression or unacceptable toxicity or intravenous ofa for up to 24 weeks. The primary end point was IRC-assessed PFS, with secondary end points of OS and ORR. In HELIOS, pts received BR (≤ 6 cycles) with either 420 mg oral ibr daily or placebo until disease progression or unacceptable toxicity. Pts with del17p were excluded. The primary end point was IRC-assessed PFS, with secondary end points of ORR and OS. Per protocol amendment in both studies, pts in comparator arms could switch to ibr upon IRC-confirmed progression. The current exploratory analysis was based on the latest available data from each trial (median time on study: RESONATE, 19 months; HELIOS, 17 months) using investigator assessments, but excluding del17p pts from RESONATE. Analyses were performed using data from both the overall CLL/SLL population and only the CLL pts. Separate multivariate Cox proportional hazards models were constructed for PFS and OS, including treatment and clinically relevant prognostic variables as covariates (age, gender, Rai staging, ECOG score, del11q status, refractory status, number of prior lines of therapy, bulky disease, IgVH status). Adjusted HRs and 95% CIs are presented vs single-agent ibr, along with predicted survival curves derived from the multivariate Cox regressions. Results RESONATE and HELIOS enrolled populations with notable differences making naïve comparison flawed. Because HELIOS enrolled only CIT-eligible pts, the trial included younger pts who had received fewer lines of therapy, as well as lower proportions of pts with purine analog refractory disease, del11q, or Rai stage 4 disease. These factors have been previously reported to influence outcomes in pts with R/R CLL/SLL and thus were included as covariates in the statistical models. Other baseline factors (gender, ECOG score, bulky disease, and IgVH status) were not notably different between the trials, but were found to impact PFS and OS and thus were included as additional covariates. In the overall CLL/SLL population, PFS and OS were comparable for single-agent ibr vs ibr + BR, and were significantly improved for single-agent ibr vs BR (Figure 1). Results for only the CLL pts were similar to those shown in Figure 1 for both PFS (ibr + BR vs single-agent ibr: 1.03 [0.61-1.75], p = 0.9042; BR vs single-agent ibr: 7.52 [4.72-11.99], p < 0.0001; single-agent ibr reduced the risk of progression/death by 87% vs BR) and OS (ibr + BR vs single-agent ibr: 1.20 [0.59-2.43], p = 0.6197; BR vs single-agent ibr: 2.24 [1.14-4.40], p = 0.0197; single-agent ibr reduced the risk of death by 55% vs BR). Conclusions The adjusted indirect comparisons reported here suggest superiority of single-agent ibr over BR for PFS and OS in patients with R/R CLL/SLL. The comparisons also suggest that the addition of BR to ibr did not improve PFS or OS compared with single-agent ibr. However, as median PFS has not been reached for either ibr arm, it is too early to draw firm conclusions. Longer follow-up in the ibr arms of these studies will be required to give an indication of whether CIT adds any benefit to ibrutinib for PFS and OS. Overall, these findings provide support for single-agent ibr as an appropriate choice for all pts with previously treated CLL/SLL. Disclosures Hillmen: Roche Pharmaceuticals: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Celgene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Honoraria, Research Funding. Fraser:Janssen: Honoraria, Research Funding, Speakers Bureau; Hoffman LaRoche: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Jones:Acerta Pharma BV: Research Funding. Rule:Roche: Consultancy, Other: Travel reimbursement; J&J: Consultancy, Other: Travel reimbursement, Research Funding; Celgene: Consultancy, Other: Travel reimbursement; Gilead: Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Jaeger:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cymbalista:Karyopharm: Honoraria; Roche: Honoraria; Gilead: Honoraria; Janssen: Honoraria, Research Funding. Sun:Janssen/J&J: Employment, Equity Ownership. Ninomoto:Pharmacyclics LLC, an AbbVie Company: Employment. Mahler:Janssen: Employment, Other: Travel reimbursement. Cheng:Pharmacyclics LLC, an AbbVie Company: Employment. Diels:Janssen: Employment. Clow:Pharmacyclics LLC, an AbbVie Company: Employment. Salman:Janssen/J&J: Employment, Equity Ownership. James:Pharmacyclics LLC, an AbbVie Company: Employment. Howes:Janssen/J&J: Employment, Equity Ownership.

Abstract Abstract 1893 Background: Recent data has shown that the level of immunoglobulin free light chain (FLC) is a prognostic factor for patients with AL amyloidosis. Approximately 25% of patients with AL amyloidosis have coexistent multiple myeloma (MM) with myeloma-related end-organ damage and patients may also present with 310% plasma cells (PC) in the bone marrow (BM) in the absence of any MM features. The goal of this study was to determine the effect of increased BM plasmacytosis in the absence of MM end-organ damage on early mortality. Methods: We performed a retrospective study of 263 consecutive patients with AL amyloidosis seen at Mayo Clinic within 30 days of diagnosis from July 2002 – April 2009, to compare the effect of PC burden among those who died within 90 days of diagnosis (n=88) and those who survived more than 90 days after diagnosis (n=175). Only those patients with documented BM PC were included in this study. MM end-organ damage was defined according to the CRAB criteria. Results: In those who died <90 days after diagnosis and patients who lived beyond 90 days, the proportion of patients with 310% BM PC were 57% and 55%, respectively. Overall survival (OS) was significantly shorter in the early mortality group when there was 310% BM PC present at diagnosis (25 vs. 54 days, p=0.006), but this was not observed in the group who survived beyond 90 days (Figure 1). In patients with 310% BM PC, troponin-T, ejection fraction (EF), and hemoglobin (Hgb) were significantly worse in the early mortality cohort but patients who survived beyond 90 days had significant increase in intraventricular septal (IVS) thickness and beta-2 microglobulin (Table 1). As expected, patients with 310% BM PC in both cohorts had significantly higher serum M-spike and involved FLC (Table). The same cohort of patients were analyzed substituting MM-related end-organ damage for 310% BM PC and similar results were observed with the exception of uric acid and calcium being significantly higher in the early mortality cohort with MM (results not shown). Conclusion: This study demonstrated that an excess of early—but not late—deaths occur in AL amyloidosis patients with 310% BM PC at diagnosis. In our cohort, this finding can be attributed to higher troponin-T levels, indicating more severe cardiac involvement as observed by worse cardiac function. These findings warrant additional investigation. Disclosures: Lacy: Celgene: Research Funding. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Dispenzieri:Celgene: Honoraria, Research Funding; Binding Site: Honoraria.

Abstract Despite improvements in front-line therapy for acute lymphoblastic leukemia (ALL), treatment after relapse remains a critical challenge. Examination of outcome after relapse in a large, recently treated, and unselected population provides a useful benchmark for evaluating new approaches. Survival after relapse was tracked on Children’s Cancer Group (CCG) ALL trials. Relapses were categorized by site (isolated or combined bone marrow relapse (MR); isolated central nervous system relapse (CNSR); isolated testicular relapse (TR)), and time from diagnosis to relapse (early < 18 months; intermediate between 18 and 36 months; late > 36 months). We examined the impact of age, sex, ethnicity, initial risk assignment (standard risk (SR) or higher risk (HR)), immunophenotype, length of first remission (CR1), and site of relapse on outcome in multivariate analyses. A total of 9,585 infants, children, and adolescents with newly diagnosed acute lymphoblastic leukemia were enrolled on CCG trials conducted between 1988 and 2002. We examined survival after relapse for 1,874 children with MR, CNSR, or TR. Survival after relapse by site and time to relapse Site MR CNSR TR Time to Relapse n *survival(%) n *survival(%) n *survival(%) *3-year survival Early 498 10 175 49 15 50 Intermediate 378 23 179 73 35 57 Late 488 53 52 77 54 70 Overall survival for any bone marrow relapse was best for late MR and worst for early MR. Early MR was linked to HR presenting features and T-cell disease. Survival after intermediate or late MR was superior for SR patients (p <.05). Survival was better for CNSR or TR than for MR. Older age at diagnosis, male sex, T cell immunopheno-type, and CNS disease at presentation were significant adverse factors for survival after adjustment for site and time to relapse in multivariate analyses (p<.05). Importantly, in the same multivariate analysis, patients treated on more contemporary trials (CCG1952CCG1953CCG1961, and 1962) had inferior survival rates after relapse when compared to patients treated on earlier trials (CCG 1881CCG 1882CCG 1883CCG 1891CCG 1901, and 1922) (p<.001). Importantly, these data from the analysis of a large, unselected group of patients indicates that features at initial presentation and prior therapy influences outcome following relapse. The inferior survival rates of those relapsing on more intensive protocols likely reflects particularly aggressive and chemoresistant disease leading to poor salvage. Increasing the intensity of retrieval therapy is unlikely to improve after relapse and novel therapeutic approaches that target these resistant leukemias are urgently needed for successful treatment of relapsed ALL.

Abstract Background: p38a mitogen-activated protein kinase (MAPK) mediates production of proinflammatory cytokines and other factors including PGE-2 induced RANKL and IL-1 induced IL-6. SCIO-469 inhibits p38a MAPK blocking synthesis of Il-1ß, PGE2, VEGF, MIP-1α and TNFα thus reducing in vitro MM tumor growth and survival, and drug resistance. Objectives: Assess efficacy, safety, tolerability of SCIO-469 as M or MB in patients (pts) with relapsed and refractory multiple myeloma. Methods: Pts were treated with SCIO-469 alone (60 mg po tid)and assessed on Days 15, 30, 52 and 73. Bortezomib (1.0–1.3mg/m2 d 1,4,8,11 q21d) was added to M for PD or SD. Pts who had clinical benefit on either M or MB at Day 73 were allowed to continue on extension study for up to a total of 168 d, to further evaluate efficacy and saftey of M or MB. Results: 62 pts were enrolled: 39 M, 23 F, median age was 63 years (range 48–84), D-S stage at Dx: I (6%), II (32), III (60%%); median time from diagnosis to treatment 3.1 years; median # prior Rx = 5; including 29% with > 6; 71% prior transplant. 27 had received prior bortezomib and 17 were considered refractory. All 62 pts received study drug; 34 pts received MB at some time during the treatment period. 5 of the 28 (18%) pts treated with M and 25 of 34 (74%) pts treated with MB continued on the extension study. Median time on study was 77.5 d (range 7–304) for M and 180.5 d (range 34–275) for MB. Best response (EBMT; Blade 1998) to M was stable disease in 24% of pts; the best response to MB was 9/34 PR (26%), 2/34 MR (6%),3/34 SD (9%). Median time to progression (TTP) was 50 days for M compared to 140 days for MB. Safety/Tolerability: Adverse events on M were tabulated separately from those on MB. Neutropenia was minimal, < 3% with either regimen; anemia (47 vs 29%) and thrombocytopenia (26 vs 16%) were more prevalent with MB vs M, respectively. Epistaxis, fatigue and diarrhea were seen in > 15% of pts receiving M. Nausea, vomiting, diarrhea, constipation, abdominal pain, fatigue, pyrexia, anorexia, URI, arthralgia, muscle cramp, dizziness, peripheral neuropathy and headache occurred in > 15% pts receiving MB. 10 pts died on study, 9 during primary phase and 1 during extension phase. 3 deaths were the result of sepsis, the remaining 7 were due to progressive disease. Conclusions: SCIO-469, 60 mg tid, as monotherapy or in combination with Bortezomib was well tolerated. Although there were no objective responses in M (compared to 32% (11/34) in MB-including 4 patients who had failed prior bortezomib), 24% had stable disease at the end of monotherapy. Further studies to refine the dose of SCIO-469 as monotherapy and of SCIO-469 in combination with other agents are warranted.

Abstract Background: Patients (pts) with CLL/SLL that have del11q tend to have relatively short remission durations and shorter overall survival (OS) with standard chemotherapy regimens. Ibrutinib (ibr), a first-in-class, oral, once-daily inhibitor of Bruton's tyrosine kinase (BTK) is indicated by the US FDA for the treatment of pts with CLL/SLL and allows for treatment without chemotherapy. In phase 3 studies, treatment with single-agent ibr was superior to treatment with ofatumumab (ofa) in relapsed/refractory (R/R) CLL/SLL (RESONATE; Byrd, N Engl J Med 2013) or chlorambucil (clb) in treatment-naïve (TN) CLL/SLL (RESONATE-2; Burger, N Engl J Med 2015); treatment with ibr + bendamustine/rituximab (BR) was also superior to treatment with BR in R/R CLL/SLL (HELIOS; Chanan-Khan, Lancet Oncol 2016). We examined the outcome of pts in these 3 studies who did or did not have del11q to determine the impact of del11q on clinical outcomes. Methods: In RESONATE, pts with R/R CLL/SLL received ibr 420 mg/day until progressive disease (PD) or unacceptable toxicity (tox) vs ofa for up to 24 weeks (300 mg week 1, 2000 mg weekly for 7 weeks, 2000 mg every 4 weeks for 16 weeks). In RESONATE-2, pts ≥65 years of age with TN CLL/SLL (excluding del17p) received ibr 420 mg/day until PD or tox vs clb 0.5 mg/kg (up to max of 0.8 mg/kg) on days 1 and 15 of each 28-day cycle (≤12 cycles). In HELIOS, pts with R/R CLL/SLL (excluding del17p) received BR (≤6 cycles) with or without ibr 420 mg/day (starting on day 2 of cycle 1) followed by single-agent ibr or placebo continued until PD or tox. Data from pts in the 3 studies were pooled (ibr pool, comparator pool) and analyzed based on whether or not their CLL/SLL had del11q. We performed a multivariate analysis to examine for risk factors prognostic for survival (del11q del17p, age, sex, race, current Rai stage, baseline ECOG PS, number of prior therapies, cytopenias; no multiplicity adjustment). Results: A total of 1210 pts with del11q data were included in the analysis: 609 in the ibr pool (179 with del11q, 430 without del11q) vs 601 in the comparator pool (149 with del11q, 452 without del11q). Demographics and baseline characteristics were generally similar in pts regardless of del11q status; differences of more than 10% included proportions with bulky disease ≥5 cm (63% vs 49%) and unmutated IGHV (88% vs 72%) in pts with or without del11q, respectively. Median lymphadenopathy and absolute lymphocyte counts were also higher in pts with del11q. At the time of the primary analysis, median treatment durations in the ibr pool were 20.0 mo with del11q and 18.7 mo without del11q; in the comparator pool 5.3 mo with del11q and 8.5 mo without del11q. Overall, ibr-treated pts had higher overall response rate (ORR) and complete response (CR) rates and longer progression-free survival (PFS, Figure) and OS than comparator-treated pts regardless of del11q status. In the ibr pool, the presence of del11q was associated with a trend of longer PFS and OS while in the comparator pool, pts with del11q had shorter PFS (Figure, Table), as compared to pts without del11q. Results were similar when excluding pts with del17p (10% of ibr pool [6%/11% with/without del11q] and 9% of comparator pool [8%/10% with/without del11q]; Table). By multivariate analysis, in the comparator pool, del11q, male sex, >1 prior therapy, presence of cytopenias, and unmutated IGHV (in R/R only) were associated with shorter PFS. However, these differences were not found in the ibr pool. The presence of del11q did not unfavorably impact the tempo of reductions in lymphadenopathy for ibr-treated pts, but did for comparator-treated pts. Adverse events leading to discontinuation were similar in ibr- and comparator-treated pts (12% [9% vs 13% with/without del11q] vs 13% [12% vs 13% with/without del11q]). Deaths within 30 days of last dose occurred in 31 pts (5% [3% vs 6% with/without del11q]) in the ibr pool and 28 pts (5% [6% vs 4% with/without del11q]) in the comparator pool. Conclusions: Treatment with ibr was superior to comparator regardless of del11q status; the benefit of ibr was most marked for pts with CLL/SLL with del11q. Presence of del11q was associated with a trend of longer PFS and OS in ibr-treated pts and shorter PFS and lower ORR in comparator-treated pts. By multivariate analysis, presence of del11q was a prognostic factor for shorter PFS for comparator-treated pts, but not for ibr-treated pts. Disclosures Kipps: Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau. Hillmen:Pharmacyclics: Research Funding; Janssen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Research Funding. Demirkan:Amgen: Consultancy. Coutre:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Research Funding; AbbVie: Research Funding; Janssen: Consultancy, Research Funding. Barrientos:Gilead: Consultancy, Research Funding; Janssen: Consultancy; AbbVie: Consultancy, Research Funding. Barr:Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; AbbVie: Consultancy. O'Brien:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria. Fraser:Celgene: Research Funding; Janssen: Honoraria, Research Funding, Speakers Bureau. Jaeger:Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses. Cramer:Janssen-Cilag: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; Novartis: Consultancy, Research Funding; GlaxoSmithKline: Research Funding; Mundipharma: Other: Travel, Accommodations, Expenses; Astellas: Other: Travel, Accommodations, Expenses; Roche: Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; Gilead: Other: Travel, Accommodations, Expenses, Research Funding. Stilgenbauer:Novartis: Consultancy, Honoraria, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Genzyme: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Hoffman La-Roche: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Genentech: Consultancy, Honoraria, Research Funding. Salman:Janssen Research & Development: Employment, Equity Ownership, Other: Travel, Accommodations, Expenses. Solman:Pharmacyclics LLC, an AbbVie Company: Employment, Other: Travel, Accommodations, Expenses; AbbVie: Equity Ownership. Cheng:Johnson & Johnson: Equity Ownership; AbbVie: Equity Ownership; Pharmacyclics LLC, an AbbVie Company: Employment. Phelps:Johnson & Johnson: Employment, Equity Ownership. Ninomoto:Pharmacyclics LLC, an AbbVie Company: Employment; Amgen, Inc.: Equity Ownership; AbbVie: Equity Ownership. Howes:Janssen: Employment, Other: Leadership; Johnson & Johnson: Equity Ownership. James:Pharmacyclics LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Hallek:Gilead: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau.

Abstract Acute lymphoblastic leukemia (ALL) in adolescents and young adults (AYA) is characterized by distinct presenting features and inferior prognosis compared to pediatric ALL. Age, as a continuous variable, is negatively correlated with prognosis, in spite of risk-adapted combination chemotherapy. To better understand the etiology of ALL in this age group, we performed the first genome-wide association study (GWAS) to comprehensively examine germline single nucleotide polymorphisms (SNPs) for their association with susceptibility to B-ALL in AYAs. In the discovery GWAS, we compared genotype frequency at 635,297 SNPs between 308 AYA ALL cases (age 16-39 years, treated on the Children’s Oncology Group [COG], the Alliance-Cancer and Leukemia Group B, Eastern Cooperative Oncology Group, MD Anderson Cancer Center, and St. Jude Children’s Research Hospital trials) vs. 6,661 non-ALL controls. The association between genotypes at each SNP and ALL susceptibility was tested by using a logistic regression model after adjusting for genetic ancestries to control for population stratification. SNPs that reached P≤ 5×10-8 in the discovery GWAS were tested in an independent cohort of 82 AYA ALL cases from the COG protocols and 5,755 non-ALL controls. We identified a single genome-wide significant susceptibility locus on 10p14 signified by two SNPs within the GATA3 gene: rs3824662, P=2.8x10-10, odds ratio (OR)=1.77; rs3781093, P=3.2x10-9, OR=1.73, both of which were validated in the replication cohort (P=1.9x10-8 and P=4.3x10-5, respectively). We also examined the association signals in AYAs for susceptibility loci previously identified in pediatric ALL: ARID5B, IKZF1 and PIP4K2A variants were nominally significant in AYAs in the discovery GWAS and/or in the replication analysis, whereas CEBPE or CDKN2A/CDKN2B were not significant. These results imply both similarities and differences in genetic predisposition to ALL between children and AYAs. At the GATA3 locus, rs3824662 risk variant was over-represented in Philadelphia chromosome (Ph)-like ALL in AYAs (P=0.02), confirming our previous report of Ph-like ALL susceptibility variants in GATA3 (Nat Genet 45:1494). Importantly, even after excluding Ph-like cases, rs3824662 remained associated with the risk of developing ALL in AYAs, suggesting that the influence of the GATA3risk variant on ALL susceptibility in AYAs extends beyond the predisposition to Ph-like subtype. We next examined the relationship between GATA3 risk allele frequency and age at diagnosis in a cohort of unselected childhood and adolescent ALL cases enrolled in the COG P9900 protocols (N=1,827). Dividing patients into four consecutives age groups (<5, 5-10, 10-15 and >15 years), we observed a clear progressive increase in the risk allele frequency at rs3824662 (P=6.29×10-11) with increasing allelic odds ratio (i.e. relative risk of ALL conferred by each copy of the risk allele). This correlation between genotype and age was evident regardless of genetic ancestry, although the risk variant was more common among individuals with higher Native American ancestry. In contrast, the frequency of ALL susceptibility variant in ARID5B decreased progressively with increasing age at diagnosis (P=0.006), whereas PIP4K2A, CDKN2A/CDKN2B, IKZF1 and CEBPE variants were not related to age. Finally, we compared rs3824662 risk variant frequency by age in the COG P9900 protocols after stratifying the ALL cases into TCF3-PBX1, ETV6-RUNX1, hyperdiploid, MLL-rearranged and B-other. There was a trend that the risk allele was more frequent in cases older than 16 years compared to those below 16 in the five subtypes examined. In conclusion, we have identified inherited GATA3 genetic variants that strongly influence ALL susceptibility in adolescent and young adults, indicating potential age-related differences in ALL biology. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 1038 The relationships of inherent disease-related characteristics and of treatment to the nature of APL cell clones that emerge at disease relapse are poorly understood. We studied these relationships in 45 patients who relapsed after ATRA/chemotherapy treatment on the non-arsenic trixoxide arm of intergroup phase III trial C9710 (Powell, et al. Blood, Epub). Four variably-expressed APL cell clonal markers were assessed: PML-RARA ligand binding domain mutations (LBD-M), FLT3 internal tandem duplication mutations (ITD), FLT3 receptor tyrosine kinase mutations (D835; RTK-M) and additional chromosome abnormalities (ACA), i.e., in addition to the hallmark t(15;17). The methods for mutation analysis of PML-RARA and FLT3 have been reported and were RNA transcript-initiated supplemented by selected quantitative FLT3 mutation analyses initiated from DNA. Karyotype data were derived by standard cytogenetic methods. Four patients were excluded from analysis because the sample level of PML-RARA, as determined by quantitative RT-PCR, was insufficient to exclude possible false-negative mutation results. In 41 evaluable patients, the marker incidences were: LBD-M, 44%; ITD, 37%; RTK-M, 12%; ACA (22 tested), 59%. At presentation, the corresponding incidences were: LBD-M, 0% (by high-sensitivity testing a minor subclone of the relapse mutation was found in 2/7 patients tested); ITD, 43% (37 tested); RTK-M, 22% (37 tested); ACA, 24% (34 tested). The low frequency of RTK-M impeded further analysis. The other markers, using relapse determinations, were assessed for potential associations between the markers and with the following parameters: age, sex, presenting WBC count, PML-RARA type, time to relapse, relapse on or off ATRA treatment (on = taking or within 30 days of discontinuing) and post-relapse survival. The most essential positive findings are summarized below:Association of Marker with Parameter or Other MarkerCases with ParameterCases without Parameterp-valuePretreatment parameters: LBD-M with WBC count < 5,000/uL12/18 (67%)7/23 (30%)0.030 ITD with WBC count >10,000/uL10/15 (67%)5/26 (19%)0.006 ITD with S-form PML-RARA15/15 (100%)10/26 (38%)<0.0001Relapse parameters: ITD with lack of ACA1/7 (14%)12/15 (80%)0.007 LBD with relapse On-ATRA11/18 (61%)7/23 (30%)0.064 Off-ATRA only: LBD with lack of ITD0/7 (0%)9/16 (56%)0.019 The results confirm reports, which tested pretreatment samples, of a strong association between FLT3ITD mutations present at relapse and high WBC count and S-form PML-RARA. At relapse, there was, also, divergent selection of ITD-harboring vs ACA-harboring clones. LBD-M occurred more frequently in patients with low presenting WBC counts. They, also, occurred in patients who relapsed while on ATRA, consistent with an ATRA selective role for clones harboring LBD mutations. A significant segregation of patients with LBD-M or ITD was observed after relapse off ATRA treatment (p = 0.019), while no segregation was observed in overall relapse patients (p = 0.346) or after relapse on ATRA (p = 0.316). In 2 patients who relapsed on ATRA, quantitative analysis indicated that LBD-M and ITD mutations must be present in the same APL cell clone. There were no significant survival differences related to any clonal marker (post-relapse survival = 66%). Although the small number of cases is cautionary, the overall data suggest that LBD-M may have an overriding, dominant APL clone selection role in relapse that occurs on ATRA therapy. Other inherent clinicopathologic characteristics of APL may predispose to divergent molecular pathways of disease progression and relapse in patients alternatively harboring clones with LBD-M or ITD after the termination of ATRA selection pressure. Disclosures: No relevant conflicts of interest to declare.