Aldoss, Ibrahim

e18506 Background: Sapanisertib (SAP) is an oral small molecule dual mTOR complex 1 and 2 (TORC1/2) inhibitor that showed activity in lymphoid neoplasms. It blocks a feedback loop involving mTORC2 activation when TORC1 is selectively inhibited (Yun S et al, Blood 2016). SAP induces apoptosis of malignant lymphoid cells in vitro and in xenografts, with greatest effects in ALL cell lines. We aim to assess potential efficacy of SAP when used as a single agent in relapsed/refractory ALL. Methods: Adults (age ≥18) with ECOG performance status 0-2 and normal organ function (creatinine/total bilirubin <1.5 upper limit of normal) with relapsed and/or refractory ALL (B- or T-cell) were enrolled. Newly diagnosed patients (pts) unfit for aggressive treatments and BCR-ABL+ ALL were allowed if there was no suitable standard treatment. SAP was given at 3 mg orally daily for 21 days every 28 days. Dose escalation was allowed after 2 cycles. Hydroxyurea and corticosteroids were not allowed after starting SAP. The primary end point was complete remission (CR) or CR with incomplete count recovery (CRi). This is a one stage Simon design study with interim analysis after 11 pts completed treatment. Enrollment was continued until interim analysis was done. Results: A total of 16 pts were enrolled on the study with a median age of 46 years old, 56% being males. 1/16 (6%) was treatment naïve. Median number of prior therapies is 3 (range, 1-9). The mean duration on SAP was 14.7 days (range 1-22). Three pts were able to start cycle 2. Safety was evaluable in 14 pts. All 14 pts had at least one G3 AE, while 10 pts had at least one G4 AE. G3/4 related non-hematological adverse events (AE) included 3 mucositis, 1 hepatic failure, 1 sepsis, 3 hyperglycemia, 1 anorexia, 1 seizure, 1 confusion, and 1 pneumonitis. One pt had G5 AE with malignancy. G3/4 hematological AEs included 2 with lymphopenia, 1 thrombocytopenia, 3 with leukopenia, and 1 with neutropenia. No pt achieved a CR/CRi. Best response was stable disease in 2 (12.5%) pts. Five pts had progressive disease while 9 were not evaluable because of early removal. Conclusions: SAP exhibited the expected safety profile. Although several pts developed cytopenias on drug, there was no evidence of clinically meaningful single-agent activity against ALL. Analysis of paired bone marrow aspirates from this trial is being performed to assess whether mTOR was substantially inhibited at therapeutically achievable drug concentrations. Clinical trial information: NCT02484430.

Background: Inotuzumab ozogamicin (InO) is an antibody-drug conjugate composed of anti-CD22 antibody conjugated to the cytotoxic agent calicheamicin, which is approved for relapsed/ refractory (RR) B-cell acute lymphocytic leukemia (ALL), based on efficacy demonstrated in a randomized control trial. We sought to investigate the safety and efficacy of InO in the "real world" setting. Methods: We conducted a retrospective multicenter study in collaboration with 11 U.S. academic institutions, and evaluated the outcome of patients (pts) with RR B-cell ALL, who received InO outside of clinical trials. These pts were evaluated for response to InO, duration of response, overall survival (OS) and toxicity. Demographic and disease characteristics were summarized using descriptive statistics. Survival curves were estimated using the Kaplan-Meier method and compared via log-rank test. Duration of response was estimated among pts who achieve complete remission (CR)/CR with incomplete count recovery (CRi). Results: From June 2016 to May 2019, 84 pts with RR-B cell ALL were identified. Baseline characteristics are summarized in Table 1. The median age of pts at InO initiation was 50 years (yrs) (range, 20-87). Twenty-two (27.5%) pts had t(9;22) (Ph+ve) and 6 (7.5%) pts had t(4;11) (MLL gene) chromosomal abnormalities. Nine (11%) and 20 (25%) pts had CNS disease at diagnosis and at relapse, respectively. Median number of therapies prior to InO was 2 (range, 0-7), 40 (48%) pts had ≥ 3 therapies and 23 (27%) pts had allogeneic stem cell transplantation (allo-HCT) prior to InO. Forty (48%) pts received blinatumomab prior to InO. Fourteen (17%) pts received InO in combination with chemotherapy and/ or tyrosine kinase inhibitor (TKI). Overall response rate (CR/CRi) was 63%; 44% had CR with minimal residual disease (MRD) negativity by flow cytometry. Response rate in Ph+ve B-cell ALL was 73%. Twenty-three (27%) pts were successfully bridged to allo-HCT. Median response duration with InO was 11.5 months (mo); 32.5% had sustained response at 2 yrs (Fig. 1a). Median response duration post InO, censored at allo-HCT was not reached (NR) (51% in remission at 2 yrs) (Fig. 1b). Median OS after InO was 11.6 mo and 32% were alive at 2 yrs (Fig. 1c). Median OS post InO, censored at of allo-HCT was 13.6 mo (Fig. 1d). Median OS after InO in Ph+ve pts was NR (71% alive at 1 yr). Forty-nine percent, 27%, 6% and 5% of pts discontinued InO due to progression, allo-HCT, adverse events and maintenance therapy, respectively. Nineteen (30%) pts had dose interruptions. In terms of toxicities, 14 (17%) and 7 (8%) pts had grade (G)1-2 and G3 transaminases secondary to InO, respectively. One pt each had G2 and G3 pancreatitis, respectively. One (1%) and 2 (2%) pts had G2 and G4 veno-occlusive disease secondary to InO, respectively. Two of these pts were treated with defibrotide. Two (2%) pts died due to InO toxicity. A complete description of adverse events are summarized in Table 1. Conclusion: Our real-world data obtained by multicenter collaboration suggest that InO was well tolerated and had significant efficacy in this heavily treated patient population of RR B-cell ALL. Disclosures Liedtke: Celator: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech/Roche: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; IQVIA/Jazz: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees; BlueBirdBio: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees; Agios: Research Funding; Amgen/Onyx: Consultancy, Honoraria, Research Funding. Aldoss:Jazz Pharmaceuticals: Honoraria, Other: travel/accommodation/expenses, Speakers Bureau; Agios: Consultancy, Honoraria; AUTO1: Consultancy; Helocyte: Consultancy, Honoraria, Other: travel/accommodation/expenses. Curran:Incyte: Research Funding; Merck: Research Funding; Gilead: Research Funding. Podoltsev:Celgene: Other: Grant funding, Research Funding; Genentech: Research Funding; AI Therapeutics: Research Funding; Agios Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Research Funding; Astellas Pharma: Research Funding; Daiichi Sankyo: Research Funding; Sunesis Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Research Funding; Pfizer: Research Funding; Astex Pharmaceuticals: Research Funding; CTI Biopharma: Research Funding; Samus Therapeutics: Research Funding; Arog Pharmaceuticals: Research Funding; Kartos Therapeutics: Research Funding; Alexion: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Yang:AstraZeneca: Research Funding; Agios: Consultancy. Mattison:Pfizer: Membership on an entity's Board of Directors or advisory committees. Advani:Pfizer: Honoraria, Research Funding; Amgen: Research Funding; Macrogenics: Research Funding; Glycomimetics: Consultancy, Research Funding; Kite Pharmaceuticals: Consultancy; Abbvie: Research Funding. Atallah:Takeda: Consultancy, Research Funding; Jazz: Consultancy; Helsinn: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Jazz: Consultancy; Helsinn: Consultancy.

Background Blinatumomab is a bispecific T cell antibody construct, that binds and allows CD-3 positive cytotoxic T cells to recognize and eradicate CD19-positive acute lymphocytic leukemia (ALL) blasts. The drug is approved for patient (pts) with relapsed/ refractory (RR) B-cell ALL and those with minimal residual disease (MRD) based on efficacy in clinical trials. We sought to evaluate the safety and efficacy of blinatumomab in the "real world" setting. Methods We conducted a retrospective multicenter study in collaboration with 11 U.S. academic institutions, and evaluated the outcome of RR B-cell ALL pts, who received blinatumomab outside of clinical trials. These pts were evaluated for response, duration of response (DOR), overall survival (OS) from the time of blinatumomab initiation and toxicity. DOR was estimated among pts who had achieved complete remission (CR)/CR with incomplete count recovery (CRi). Survival curves were estimated using the Kaplan-Meier method and compared via log-rank test. Results From December 2014 to May 2019, 239 pts with B-cell ALL were identified. Baseline characteristics are summarized in Table 1. The median age of pts at blinatumomab initiation was 48 years (yrs) (range, 18-85). Sixty-one (26%) pts had Philadelphia chromosome [t(9;22)] positive (Ph+ve) disease. Sixty-one (26%) pts had ≥ 3 prior therapies and 46 (19%) pts had allogeneic stem cell transplantation (allo-HCT) prior to blinatumomab. Twenty-two (9%) pts received inotuzumab ozagamicin prior to blinatumomab. Twenty-nine (12%) pts received blinatumomab in combination with tyrosine kinase inhibitor (TKI). Twelve (5%) pts received blinatumomab for MRD. Response rate (CR/CRi) in pts with RR disease was 61%; 44% had CR with MRD negativity by flow cytometry. Rate of CR/CRi in Ph+ve B-cell ALL was 74.5%. Among 12 pts who received Blinatumomab for MRD, 9 (75%) pts achieved MRD negativity. Overall 113 (48%) pts were successfully bridged to allo-HCT. Median DOR in pts with RR disease was 32.1 months (95% CI; 9.5-not reached [NR]) (Fig. 1a) and when censored at allo-HCT was 14.8 months (95% CI; 5.2-NR) (Fig. 1b). Median OS in pts with RR disease after blinatumomab was 12.7 months (95% CI; 9.2 -17.9) (Fig. 1c) and when censored at allo-HCT was 8.6 months (95% CI; 6.4-11.6) (Fig.1d). Median OS after blinatumomab in RR B-cell ALL Ph+ve pts was NR (59% alive at 2 yr). Among pts who received blinatumomab for MRD, median DOR was NR and 54% sustained MRD negativity at 2 yrs. Median OS was 34.7 months (95% CI; 8.8-34.7) in group of pts who received blinatumomab for MRD. Seven (3%) pts discontinued blinatumomab due to adverse events and 40 (21%) pts had dose interruptions. Cytokine release syndrome (CRS) of any grade (G) was reported in higher number of pts (93 [39%]) compared to clinical trials, though G3-4 CRS appears to be similar (G1-2 [36%], G3-4 [3%]). Forty-four (44%) pts were treated with steroids and 8 (8%) pts required tocilizumab with steroids for CRS. Ninety-three percent of pts had complete resolution of CRS. CNS toxicities were observed in 31 (13%) pts, among them 60% (n= 19) had G3-4 toxicities. Hepatic toxicities were observed in 84 (35%) pts as outlined in Table 1. Six (2.5%) pts died due to blinatumomab induced toxicities. Conclusion: Our real-world data with multicenter collaboration suggest that overall blinatumomab was well tolerated and had led to significant response in pts with RR B-cell ALL. Disclosures Advani: Amgen: Research Funding; Abbvie: Research Funding; Pfizer: Honoraria, Research Funding; Macrogenics: Research Funding; Kite Pharmaceuticals: Consultancy; Glycomimetics: Consultancy, Research Funding. Aldoss:AUTO1: Consultancy; Helocyte: Consultancy, Honoraria, Other: travel/accommodation/expenses; Agios: Consultancy, Honoraria; Jazz Pharmaceuticals: Honoraria, Other: travel/accommodation/expenses, Speakers Bureau. Podoltsev:Agios Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Research Funding; Astellas Pharma: Research Funding; Alexion: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Research Funding; Sunesis Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Research Funding; Pfizer: Research Funding; Astex Pharmaceuticals: Research Funding; CTI Biopharma: Research Funding; Celgene: Other: Grant funding, Research Funding; Genentech: Research Funding; AI Therapeutics: Research Funding; Samus Therapeutics: Research Funding; Arog Pharmaceuticals: Research Funding; Kartos Therapeutics: Research Funding. Curran:Incyte: Research Funding; Merck: Research Funding; Gilead: Research Funding. Yang:Agios: Consultancy; AstraZeneca: Research Funding. Mattison:Pfizer: Membership on an entity's Board of Directors or advisory committees. Liedtke:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; IQVIA/Jazz: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech/Roche: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celator: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees; BlueBirdBio: Research Funding; Amgen/Onyx: Consultancy, Honoraria, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees; Agios: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Atallah:Helsinn: Consultancy; Takeda: Consultancy, Research Funding; Jazz: Consultancy; Pfizer: Consultancy; Helsinn: Consultancy; Novartis: Consultancy; Jazz: Consultancy.

Abstract The prognosis of elderly patients (pts) with acute lymphoblastic leukemia (ALL) remains poor, and novel therapeutic approaches are clearly needed. CD19 is expressed on the majority of precursor-B ALLs and represents an attractive therapeutic target. The anti-CD19 bi-specific engager antibody blinatumomab has demonstrated significant activity in both relapsed/refractory ALL and minimal residual disease (MRD) positive ALL. Therefore, we evaluated blinatumomab as a single agent in the upfront treatment of newly diagnosed elderly pts with Philadelphia chromosome (Ph) negative B-lineage ALL to determine response rates and overall survival (OS). Methods: Pts were treated at National Clinical Trial Network sites from June 2015 to September 2017. The primary objective of the study was to estimate 3-year OS. An IND was approved by the FDA and the protocol was approved by a central institutional review board. Eligibility: age > 65 years, newly diagnosed Ph negative B-lineage ALL with adequate organ function and no evidence of central nervous system (CNS) disease. Pts received blinatumomab for induction at standard dosing for 1-2 cycles until attainment of complete response (CR) or CR with incomplete count recovery (CRi) (defined below). Pts then received 3 cycles of blinatumomab post-remission therapy followed by 18 months of maintenance POMP (prednisone, vincristine, 6-mercaptopurine, methotrexate). A total of 8 doses of intrathecal methotrexate were administered as CNS prophylaxis. Cytogenetic risk was ascribed by NCCN 2018 criteria and bone marrow samples were analyzed for the presence of the Ph-like signature. MRD was assessed centrally by 8 color flow cytometry pre-treatment, on Day 35 of induction cycle 1, and on Day 35 of re-induction (if applicable). Response was assessed at the completion of 1-2 cycles of blinatumomab. CR was defined as < 5% marrow blasts with no evidence of extramedullary disease and recovery of counts [absolute neutrophil count (ANC) > 1000/uL, platelets >100,000/uL]. CRi was defined the same as CR but ANC < 1000/ uL and/ or platelets ≤ 100,000/ uL. OS was measured from day of registration on trial until the date of death. Disease-free survival (DFS) was measured from the date the pt achieved CR/ CRi until relapse or death. Toxicities were graded according to NCI CTCAE version 4.0. Results: Of 31 pts enrolled, 29 were eligible. The median age was 75 years (range 66 - 84), 22 (76%) were male, median baseline white blood count was 3.7 x 103/uL (range 0.3 - 7,100), and median bone marrow blast count percentage was 86.5% (range 30-100). Three pts received hydroxyurea or steroids prior to treatment initiation. Cytogenetic risk at diagnosis was: poor (34% of pts; n=10), standard (55% of pts; n=16), good (3% of pts; n=1) and unknown (7% of pts, n=2). Testing for the Ph-like signature is being completed. The most common Grade 3-5 non-hematologic toxicities related to treatment during induction were hyperglycemia (14%), dyspnea (10%), febrile neutropenia (10%), hypertension (10%), and lung infection (7%). One pt developed Grade 3 cytokine release syndrome and 1 developed Grade 3 neurotoxicity. No pts died during the first 28 days of treatment. The overall response rate (CR + CRi) was 66% (all CRs). Thirteen of the 19 responders have available MRD data post-treatment. Of these, 12 pts (92%) achieved MRD negativity, all at Cycle 1 Day 35. One pt required 2 cycles of blinatumomab to achieve CR. One pt proceeded to allogeneic hematopoietic stem cell transplant. The median follow-up time is 1 year and median duration on trial is 170 days (6 pts are still on maintenance therapy). OS estimated by Kaplan Meier at 6 months is 79% (95% CI 58%-90%) and at 1 year is 65% (95% CI 43%-80%). DFS estimated at 6 months is 68% (95% CI 43%-84%) and at 1 year is 56% (95% CI 31%-75%). No baseline features including CD19 expression (by percentage or mean-fluorescent intensity) or presence of a CD19 negative subpopulation were associated with response. Conclusions: Blinatumomab was well tolerated and effective in the treatment of newly diagnosed elderly patients with Ph negative B-lineage ALL. Further follow up will determine the durability of these responses. Disclosures Advani: Pfizer: Honoraria, Research Funding; Amgen: Research Funding; Novartis: Consultancy; Glycomimetics: Consultancy. Wieduwilt:Leadiant: Research Funding; Merck: Research Funding; Shire: Research Funding; Reata Pharmaceuticals: Equity Ownership; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding. Park:Adaptive Biotechnologies: Consultancy; Pfizer: Consultancy; AstraZeneca: Consultancy; Novartis: Consultancy; Kite Pharma: Consultancy; Juno Therapeutics: Consultancy, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Shire: Consultancy. Stock:Jazz Pharmaceuticals: Consultancy. Erba:Immunogen: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Agios: Consultancy, Speakers Bureau; Takeda/Millenium: Research Funding; Amgen: Research Funding; Novartis: Consultancy, Speakers Bureau; Juno: Research Funding; Juno: Research Funding; Celgene: Consultancy, Speakers Bureau; Daiichi Sankyo: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Takeda/Millenium: Research Funding; Incyte: Consultancy, Speakers Bureau; MacroGenics: Consultancy; Jazz: Consultancy, Speakers Bureau; MacroGenics: Consultancy; Agios: Consultancy, Speakers Bureau; Immunogen: Consultancy, Research Funding; Amgen: Research Funding; Agios: Consultancy, Speakers Bureau; Astellas: Research Funding; MacroGenics: Consultancy; Takeda/Millenium: Research Funding; Seattle Genetics: Consultancy, Research Funding; MacroGenics: Consultancy; Novartis: Consultancy, Speakers Bureau; Amgen: Research Funding; Novartis: Consultancy, Speakers Bureau; Janssen: Research Funding; Celgene: Consultancy, Speakers Bureau; Immunogen: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Janssen: Research Funding; Jazz: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Amgen: Research Funding; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Pfizer: Consultancy, Other: grant; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Astellas: Research Funding; Pfizer: Consultancy, Other: grant; Celgene: Consultancy, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Incyte: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Agios: Consultancy, Speakers Bureau; Pfizer: Consultancy, Other: grant; Incyte: Consultancy, Speakers Bureau; Juno: Research Funding; Jazz: Consultancy, Speakers Bureau; Pfizer: Consultancy, Other: grant; Astellas: Research Funding; Seattle Genetics: Consultancy, Research Funding; Takeda/Millenium: Research Funding; Immunogen: Consultancy, Research Funding; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Juno: Research Funding; Jazz: Consultancy, Speakers Bureau.

Abstract Abstract 845 Background: Waldenstrom's macroglobulinemia (WM) is a relatively uncommon plasma cell disorder and most of previous literature is limited to small patient series. We have noted ethnic disparities in multiple myeloma, another plasma cell disorder. We undertook a large Surveillance Epidemiology and End Results (SEER) based analysis to describe outcome disparities in different subgroups of WM patients, with a focus on various ethnicities, so that therapeutic resources can be targeted more effectively. Methods: The SEER 17 Registry data (1973–2008) was utilized for patients with confirmed diagnosis of WM. To avoid bias of under representation of different ethnicities, analysis was restricted to patients with a diagnosis date of 1992 or later. Cases that received a diagnosis at death certificate or autopsy, no follow-up records, as well as lacking documentation on age at diagnosis, sex, or race/ethnicity were excluded. Cox proportional hazards models, adjusted for gender, age, race, year of diagnosis, marital status and stratified by SEER registries were used to evaluate associatio n between patient characteristics and survival. All statistical tests were two-sided and utilized the SAS software (v9.2) with a significance level of 0.05. Results: The final analysis included 2,840 WM patients (1,759 males; 62%, 1,081 females; 38%). The studied age-group cohorts included: 18–64 yrs (845; 30%), 65–74 yrs (795; 28%) and >75 yrs (1,200; 42%). Patients were stratified by race/ethnicity: White (2,471; 87%), African-American (AA) (102; 4%), Hispanic (133; 5%), Asian (129; 5%), and Native American (5; 0.1%). Patients were also stratified based on year of diagnosis (before or after 2002) to study the impact of certain novel agents (proteasome inhibitors, IMiDs) on WM treatment. There was a significant difference in the age at diagnosis of WM patients across different ethnicities, with AA the youngest (median 61.5 years) and Whites the oldest (median 73 years) subgroup (p<0.001). (Figure 1) Cause-specific mortality could not be evaluated due to variable documentation of reported causes of death for WM patients in the database. Survival analysis revealed that for all patients, females had better median overall survival (OS) than males (7.3 years vs. 6.2 years, HR 0.834; 95% CI 0.740, 0.939; p=0.003). Among the different age cohorts, patients with age ≥75 years had a significantly worse median OS (4.1 years) than those 65–74 year-old (7.3 years) or 18–64 year-old (10+ years) (p<0.001). Patients diagnosed after 2002 had a significantly better median OS (7.3 years) as compared to patients diagnosed previously (6.1 years) (p=0.002). Hispanics had the worst median OS (5 years) and Whites had the best median OS (6.8 years) across various ethnicities. In a multivariate model using gender, age, marital status, year of diagnosis and race, a significant interaction was noted between race, age and survival, with Hispanics having a significantly worse OS than Whites (HR 1.86; 95% CI 1.269, 2.726; p=0.003) (Figure 2). Conclusions: Studies of outcome disparities are important for evaluating disease characteristics and management needs of specific patient populations as well as optimal triaging of healthcare resources. We have performed the largest population-based analysis for WM including various ethnicities in the novel therapeutic agent era. We observed that AA patients had a significantly younger age at WM diagnosis. Older patients had worse OS across all ethnic subgroups and patients diagnosed after 2002 had a better OS suggesting an impact of novel therapeutic agents (e.g., proteasome inhibitors, IMiDs). Hispanic WM patients had the worst OS among all ethnicities. This survival difference was more significant and pronounced in patients >75 years. This suggests that the impact of race on survival is influenced by patient's age. These results will help in better understanding of various influences on disease biology and clinical behavior. Disclosures: No relevant conflicts of interest to declare.

Abstract Total body irradiation (TBI)-based conditioning regimens are considered the standard of care for patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic cell transplantation (HCT). However, due to concerns regarding acute and long-term toxicities, non-TBI regimens, commonly including busulfan (BU), have been increasingly explored. We performed a retrospective cohort analysis with the hypothesis that there would be equivalence of these two myeloablative approaches by reviewing outcomes for adult patients (pts), aged 18-60 years, undergoing a first, well-matched sibling, related or unrelated donor HCT in CR1 or CR2 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) from 2005-2014. Eight hundred nineteen pts received TBI (63% 9-12 Gy, 37% ≥13 Gy) combined with etoposide (25%) or cyclophosphamide (Cy) (75%) and 299 pts received intravenous BU combined with a second alkylator Cy (15%) or melphalan (Mel) (13%), or a nucleoside analogue fludarabine (Flu) (41%) or clofarabine (Clo)(30%). The majority of the BU-based pts were treated at the Moffitt or MD Anderson Cancer Center. The BU-based regimens were grouped together for analyses since no significant differences in basic outcomes among the different chemotherapy-only regimens were noted. Patients in the BU-containing group were older but had better performance status, took longer to achieve CR1 and longer to receive HCT; more received peripheral blood than marrow grafts, peri-HCT ATG, pre- and post HCT tyrosine kinase inhibitors ( TKI), and were treated more recently than pts in the TBI-based group (Table 1). With median follow-up of 3.6 years for the BU-based group and 5.3 years for the TBI-based group, adjusted 3 year outcomes showed treatment-related mortality (TRM) BU 19% vs. TBI 25% (p=.04); relapse BU 37% vs. TBI 28% (p=.007); disease-free survival (DFS) Bu 45% vs. TBI 48% (p=.35); and overall survival (OS) BU 57% vs. TBI 53% (p=.35) (Figures A-B). Patients in the BU group had significantly more grade II-IV acute GVHD (47% vs. 40%, p=.025), but marginally less chronic GVHD (49% vs. 55% at 3 years, p=.073). In multivariate analysis, the BU group had a significantly higher rate of acute GVHD after day 50 (RR 1.75, 95% CI 1.19-2.58, p=.004), but marginally less chronic GVHD (RR 0.83, 95% CI 0.68-1.01 p=.059) and higher risk of relapse (RR 1.46, 95% CI 1.15-1.85 p=.002) compared with TBI-based regimens. Despite the observed higher risks of acute GVHD and relapse, BU-based conditioning led to similar TRM, OS, and DFS following HCT for ALL. Table 1 Table 1. Figure Figure. Disclosures Ciurea: Spectrum Pharmaceuticals: Other: Advisory Board; Cyto-Sen Therapeutics: Equity Ownership. Seftel:Otsuka: Research Funding. Pulsipher:Medac: Other: Housing support for conference; Chimerix: Consultancy; Jazz Pharmaceutical: Consultancy; Novartis: Consultancy, Other: Study Steering Committee. Champlin:Ziopharm Oncology: Equity Ownership, Patents & Royalties; Intrexon: Equity Ownership, Patents & Royalties.

SummaryStudies of ethnic disparities in malignancies have revealed variation in clinical outcomes. In multiple myeloma (MM), previous literature has focused only on patients of Caucasian and African‐American (AA) descent. We present a Surveillance Epidemiology and End Results (SEER)‐based outcome analysis of MM patients from a broader range of ethnicities, representing current United States demographics. The SEER 17 Registry data was utilized to analyse adult MM patients diagnosed since 1992 (n = 37 963), as patients of other ethnicities were not well represented prior to that. Overall survival (OS) and myeloma‐specific survival (MSS) were compared across different ethnicities stratified by year of diagnosis, registry identification, age, sex and marital‐status. Hispanics had the youngest median age at diagnosis (65 years) and Whites had the oldest (71 years) (P < 0·001). Increased age at diagnosis was an independent predictor of decreased OS and MSS. Asians had the best median OS (2·7 years) and MSS (4·1 years), while Hispanics had the worst median OS (2·4 years). These trends were more pronounced in patients ≥75 years. Cumulative survival benefit over successive years was largest among Whites (1·3 years) and smallest among Asians (0·5 years). These disparities may be secondary to multifactorial causes that need to be explored and should be considered for optimal triaging of healthcare resources.