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Introduction: Belumosudil (KD025) is a novel oral selective rho-associated coiled-coil kinase 2 (ROCK2) inhibitor specifically designed for the treatment of cGVHD, an immune-mediated inflammatory and fibrotic disorder. In a previous dose-finding study (KD025-208, N=54), two-thirds of patients, including those with fibrotic and inflammatory manifestations, achieved a partial or complete response with belumosudil. Herein, we report on the top-line results (6 months after the last patient in) from the pivotal phase 2 trial (ROCKstar [KD025-213], N=132). Methods: This phase 2, open-label, randomized, multicenter study evaluated belumosudil 200 mg QD (n=66) and BID (n=66) in patients with cGVHD who received 2 to 5 prior lines of therapy (LOT). Treatment continued until clinically significant progression of cGVHD. The primary end point was overall response rate (ORR), defined per the 2014 National Institutes of Health Consensus Criteria. Additional end points included duration of response (DOR), Lee Symptom Scale (LSS) score, failure-free survival (FFS), corticosteroid (CS) dose reductions and overall survival. The study was powered such that the lower bound of the 95% confidence interval (CI) excludes 30%, with appropriate multiplicity adjustment. Results: At enrollment, the median age was 56 years, the median time from cGVHD diagnosis to enrollment was 29 months, 67% of patients had severe cGVHD, 52% had ≥4 organs involved, 72% had received ≥3 prior LOT (including ibrutinib [n=46] or ruxolitinib [n=38]) and 73% were refractory to their last LOT. The baseline characteristics of both arms were well balanced. With a median follow-up of 8 months, the ORR (95% CI) with belumosudil 200 mg QD and BID was 73% (60%-83%) and 74% (62%-84%), respectively (Table 1). In patients who previously received ruxolitinib (29%), the ORR with belumosudil 200 mg QD and BID was 65% (41%-85%) and 72% (47%-90%), respectively. In patients who previously received ibrutinib (35%), the ORR with belumosudil 200 mg QD and BID was 73% (50%-89%) and 71% (49%-87%), respectively. High ORRs were seen in all patient subgroups, regardless of length of time from diagnosis to treatment, including those with severe cGVHD, involvement of ≥4 organs and a refractory response to prior LOT (Figure 1). The response rate was similar across all affected organs. The median time to response was 4 weeks. Of responders, 49% have maintained response for ≥20 weeks. The median DOR has not yet been reached. Clinically meaningful improvement (≥7-point reduction) in LSS score on consecutive assessments was observed in 39% and 33% of patients in the QD and BID groups, respectively. Both responders (43%) and nonresponders (17%) experienced a clinically meaningful improvement in LSS score. FFS was 77% (69%-84%) at 6 months. CS and calcineurin inhibitor discontinuations were seen in 18% and 13% of patients, respectively. Belumosudil was well tolerated, with >95% relative dose intensity in 83% of patients. Drug discontinuation occurred in 10% of patients due to possible drug-related adverse events (AEs), 3% due to progression of underlying disease and 12% due to progression of cGVHD. AEs were consistent with those expected in patients with cGVHD receiving CS and other immunosuppressants (Table 2). Common AEs included fatigue (32%), diarrhea (29%), nausea (26%), cough (24%), dyspnea (24%), upper respiratory tract infection (23%), peripheral edema (21%) and headache (20%). At least 1 serious AE occurred in 34% of patients. Twenty-three percent of patients had at least 1 liver-related investigation; the most common was increased gamma-glutamyltransferase (11%), and only 1 patient showed an increase in bilirubin. Eight patients died during the study; 5 due to AEs (1 possibly related to belumosudil) and 3 during long-term follow-up (>28 days after last dose). There were no reports of cytomegalovirus reactivation or infection. Conclusion: Treatment with belumosudil at both doses resulted in high ORRs across key subgroups, meeting the primary end point of this pivotal randomized trial in cGVHD. Responses were durable and clinically meaningful, irrespective of patient and cGVHD characteristics, and were seen in patients who previously received ruxolitinib and ibrutinib. Belumosudil was well tolerated, with limited and manageable AEs. Further studies will evaluate its use earlier in disease management. The 12-month data analysis will be presented at ASH 2020. Download : Download high-res image (508KB) Download : Download full-size image Disclosures Cutler: Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kadmon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Medsenic: Consultancy, Membership on an entity's Board of Directors or advisory committees; Generon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Mesoblast: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lee: Pfizer: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Amgen: Research Funding; Kadmon: Research Funding; AstraZeneca: Research Funding; Novartis: Research Funding; Takeda: Research Funding; Syndax: Research Funding. Rotta: Merck: Speakers Bureau; Jazz Pharma: Speakers Bureau. Ramakrishnan: Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Cigna: Honoraria. Eiznhamer: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Schueller: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Yang: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Green: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Aggarwal: Kadmon Corporation, LLC: Consultancy; Angiocrine Bioscience, Inc: Current Employment, Other: stock options. Blazar: BlueRock Therapeutics: Research Funding; BlueRock Therapeuetic: Consultancy; Fate Therapeutics Inc.: Research Funding; Magenta Therapeutics: Consultancy; Childrens' Cancer Research Fund: Research Funding; KidsFirst Fund: Research Funding; Tmunity: Other: Co-founder. Jagasia: Ocugen: Other; Mallinckrodt: Research Funding; Janssen: Research Funding.

The most common preparative regimen for autologous transplantation (ASCT) in myeloma (MM) consists of melphalan 200 mg/m2 (MEL 200). Higher doses of melphalan 220–260 mg/m2, although relatively well tolerated, have not shown significant improvement in clinical outcomes. Several approaches have been pursued in the past to improve CR rates, including poly-chemotherapy preparative regimens, tandem ASCT, consolidation, and/or maintenance therapy. Since there is a steep dose–response effect for intravenous melphalan, we evaluated an alternative single ASCT strategy using higher-dose melphalan at 280 mg/m2 (MEL 280) with amifostine as a cytoprotectant as the maximum tolerated dose determined in an earlier phase I dose escalation trial. We report the final long-term outcomes of MM patients who underwent conditioning with MEL 280 with amifostine cytoprotection followed by ASCT. Although the complete response rate was quite high in the era pre-dating the routine use of novel therapies (proteasome inhibitors, immunomodulatory agents) (49%), the progression-free survival was a disappointing 22 months. The implications of this dichotomy between the excellent depth of ASCT response and progression-free survival are discussed.

Objectives: Allogeneic hematopoietic stem cell transplant (HCT) continues to evolve with the treatment in higher risk patient population. This practice mandates stringent update and validation of risk stratification prior to undergoing such a complex and potentially fatal procedure. We examined the adoption of the new comorbidity index (HCT-CI/Age) proposed by the Seattle group after the addition of age variable and compared it to the pre-transplant assessment of mortality (PAM) that already incorporates age as part of its evaluation criteria. Methods: A retrospective analysis of adult patients who underwent HCT at our institution from January 2010 through August 2014 was performed. Kaplan-Meier’s curve, log-rank tests, Cox model and Pearson correlation was used in the analysis. Results: Of the 114 patients that underwent allogeneic transplant in our institution, 75.4% were ≥40 years old. More than 58% had a DLCO ≤80%. Although scores were positively correlated (correlation coefficient 0.43, p

Background: Patients with TP53 MUT MDS/AML experience poor clinical outcomes with high rates of disease recurrence and short overall survival (OS). Characterization of these individuals' post-HCT mortality is uniquely challenging due to competing risks from disease relapse and treatment toxicity. Transplant registries contain high-level outcomes data, however, there is a lack of detailed data in molecularly defined subsets of diease. This analysis was undertaken to bridge this gap. Methods: Allogeneic HCT recipients between 1/2014 and 12/2018 were retrospectively studied. Key inclusion criteria were TP53 MUT by NGS or deletion of chromosome 17/17p by FISH/cytogenetics. The primary outcome of non-relapse mortality (NRM) was defined as death from any cause other than disease with relapse as competing risk. Secondary outcomes for this analysis were OS, cumulative incidence of relapse (CIR), and relapse free survival (RFS). Relapse was defined as relapse/progression with NRM as competing risk. Results: 384 TP53 MUT MDS/AML patients were analyzed. 55% of patients were transplanted for AML, 41% received myeloablative conditioning (MAC), 39% had secondary MDS/AML, and 26% received prior chemo and/or radiation therapy (XRT). Median time from HCT to last follow-up was 321 days (range 8-2,385 days). Mutational data was available in 264 patients and cytogenetic data was available in 368 patients; 78% of patients had a complex karyotype (CK), 82% had TP53 missense mutations, and 74% had bi-allelic targeting of the TP53 gene. The incidence of all-grade acute and chronic GVHD (cGVHD) was 52% and 31%, respectively. One and 2 year OS was 48.5% and 30.9%, respectively. Estimated CIR at 1 and 2 years was 49% and 54.9%, respectively. The 1 year NRM was 13.7% and 2 year NRM was 18.1%. In multivariate analysis (MVA), there was no association between NRM and the clinical, molecular, or genetic features of TP53 MUT MDS/AML. HCT diagnosis of MDS (HR: 0.67, 95% CI: 0.46-0.97, p: 0.036), mono-allelic TP53 MUT (HR: 0.6, 95% CI: 0.39-0.94, p: 0.023), achievement of full donor PB chimerism (HR: 0.33, 95% CI: 0.14-0.85, p: 0.022), BM chimerism (HR: 0.33, 95% CI: 0.18-0.60, p: 0.003), and cGVHD (HR: 0.35, 95% CI: 0.23-0.51, p: In subgroup analysis, history of chemo and/or XRT increased NRM in AML (HR: 4.24, 95% CI: 1.35-13.39, p: 0.014). Pre-HCT TP53 MUT persistence by NGS (HR: 3.59, 95% CI: 1.43-9, p: 0.007) predicted for post-HCT relapse whereas pre-HCT CR (HR: 2.93, 95% CI: 1.54-5.59, p: 0.001) and full donor BM chimerism (HR: 0.14, 95% CI: 0.05-0.38, p: No significant NRM associations were identified in MDS. CK (HR: 5.04, 95% CI: 1.95-13.01, p: Conclusions: From this large multi-institutional cohort of TP53 MUT myeloid neoplasms, we report a low NRM rate, likely due to high rates of post-HCT relapse/progression. These data demonstrate associations between bi-allelic TP53m/CK and post-HCT outcomes. Our work highlights the importance donor chimerism after HCT and provides new understanding of the importance of chronic GVHD in TP53 MUT MDS/AML. Figure 1 Figure 1. Disclosures Byrne: Karyopharm: Research Funding. Logan: Amgen, Pfizer, AbbVie: Consultancy; Pharmacyclics, Astellas, Jazz, Kite, Kadmon, Autolus, Amphivena: Research Funding. Lee: CareDx: Membership on an entity's Board of Directors or advisory committees; Kadmon: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Fresensius Kabi: Consultancy; Jazz,: Consultancy; Incyte: Research Funding. Goodman: Seattle Genetics: Consultancy, Speakers Bureau; EUSA Pharma: Consultancy, Honoraria. Gill: Interius Biotherapeutics: Current holder of stock options in a privately-held company, Research Funding; Novartis: Other: licensed intellectual property, Research Funding; Carisma Therapeutics: Current holder of stock options in a privately-held company, Research Funding. Jimenez: Takeda: Research Funding; AbbVie: Research Funding. Metheny: Pharmacosmos: Honoraria; Incyte: Speakers Bureau. Bhatnagar: Pfizer: Honoraria; Celgene: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Cell Therapeutics: Honoraria, Research Funding; Kite: Honoraria; Karyopharm: Honoraria, Research Funding; Sumitomo Dainippon Pharma: Research Funding. Hamilton: Syndax: Membership on an entity's Board of Directors or advisory committees; Equilium: Membership on an entity's Board of Directors or advisory committees. Mishra: Novartis: Research Funding. Savona: BMS-Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Geron: Consultancy, Membership on an entity's Board of Directors or advisory committees; NOVARTIS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ALX Oncology: Research Funding; Astex: Research Funding; Incyte: Research Funding.

Background: Acute myeloid leukemia (AML) is an aggressive malignancy of the bone marrow characterized by resistance to treatment and dismal outcomes, especially in the elderly. Novel approaches are desperately needed. Exportin 1 (XPO1) is involved in the selective nuclear export of certain proteins and RNA species. It is overexpressed in a subset of AML, conferring an adverse prognosis. Selinexor is a small-molecule inhibitor of XPO1 with activity in AML. Selinexor sensitizes AML cells to anthracyclines by retaining topoisomerase II in the nucleus resulting in increased DNA strand breaks. Furthermore, selinexor has shown encouraging results when combined with chemotherapy in AML. This abstract reports the ongoing results of a randomized phase II study of induction and consolidation with or without selinexor in newly diagnosed patients with AML, 60 years of age or older and preclinical studies to assess the mechanisms of chemo-sensitization. Methods: Patients 60 years of age or older with newly diagnosed de novo AML were randomized 3:1 between 7+3+selinexor or 7+3. Responding patients could go on to high dose cytarabine consolidation with or without selinexor as per initial randomization. Patients in the selinexor arm who completed all consolidation could then move to maintenance therapy with selinexor alone. Induction consisted of cytarabine 100 mg/m2/d by continuous infusion for 7 days and daunorubicin 60 mg/m2 on days 1-3. Consolidation consisted of cytarabine at 1.5 gm/m2 given Q12 hours days 1-3 with G-CSF given 24 hours following the last dose of cytarabine. Selinexor was dosed at 60 mg PO on days 1, 3, 8, 10, 15 and 17 during induction and consolidation and on days 1 and 8 every 21 days during maintenance. Preclinical studies were conducted with murine AML cell lines. Results: Twenty-seven of a planned twenty-eight patients were enrolled to date. Of the 27 evaluable patients, 20 were randomized to the selinexor arm and 7 to the control arm. Baseline demographics are listed in Table 1. In the standard arm, both 30- and 60-day mortality were 14% (1/7). In the selinexor arm, both 30- and 60-day mortality were 10% (2/20). In the standard arm, 43% (3/7) of patients achieved a complete remission (CR) or complete remission with incomplete count recovery (CRi). Of the 3 responders 1 has gone on to transplant. In the selinexor arm, 85% (17/20) of patients achieved a CR or CRi. Of the 17 responders, 4 have gone on to transplant. Progression free and overall survival both favor the selinexor arm with trends towards significance despite the small size of the trial (Figure 1 and Table 2). No difference in the AE profile was noted between arms and no unexpected side effects were observed. Selinexor induces retention of topoisomerase II in the nucleus increasing sensitivity to anthracyclines. To determine if selinexor sensitized to cytarabine viability assays using murine AML cell lines were done (Figure 2A). Selinexor significantly sensitized both cell lines to cytarabine. AML cells increase mitochondrial oxygen consumption in response to cytarabine leading to resistance. The ability of selinexor to interfere with this response was assessed using Seahorse flux analysis. AML cells treated with cytarabine for 16 hours showed a diminished mitochondrial oxygen response when co-treated with selinexor (Figure 2B). Conclusions: Selinexor in combination with standard induction and consolidation therapy appears highly active in older patients with de novo AML. Selinexor may increase response to cytarabine by interfering with nuclear-mitochondrial communication. Enrollment is ongoing. Disclosures Pardee: Rafael Pharmaceuticals: Consultancy; AbbVie: Consultancy; Genentech, Inc.: Consultancy; BMS: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Research Funding; Rafael: Research Funding; Celgene: Consultancy, Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Pharmacyclics: Speakers Bureau. Ellis:Rafael Pharmaceuticals: Consultancy. Howard:Jazz Pharmaceuticals: Consultancy. Powell:Jazz Pharmaceuticals: Consultancy, Other: Advisor, Research Funding; Genentech: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Rafael Pharmaceuticals: Consultancy, Other: Advisor, Research Funding. OffLabel Disclosure: Selinexor for the treatment of AML

The azanucleotide decitabine is used in the treatment of acute myeloid leukemia (AML). Studies have shown conflicting results with 10-day regimens used in previously untreated AML patients. Additionally, there is little data on 10-day decitabine regimens in the relapsed setting. This study investigated outcomes of 108 adult patients with AML in the upfront and relapsed setting treated with a 10-day decitabine regimen. In the upfront group, the overall response rate (ORR, CR + CRi) was 36.1% and the median overall survival (OS) was 6.6 months, while the relapsed/refractory group had an ORR of 25% with an OS of 4.8 months. When analyzed with respect to cytogenetics, the upfront group featured an ORR of 28.1% with an OS of 9.4 months in the intermediate cytogenetic cohort compared to a 40.5% ORR and an OS of 5.4 months in the unfavorable cytogenetic cohort. An analysis of the relapsed/refractory group demonstrated an ORR of 26.3% with an OS of 7.9 months for intermediate cytogenetics versus 25.0% with an OS of 1.8 months in the unfavorable cohort. While these response rates are similar to previously published data, the median OS appears shorter.

Background The Hematopoietic Cell Transplantation (HCT) – Specific Comorbidity Index (HCT-CI) measures the risk of transplant related mortality and predicts overall survival (OS) based on co-morbidities. In a prospective validation study of the HCT-CI by the Center for International Blood and Marrow Transplant Research (CIBMTR), HCT-CI ≥ 3 was associated with lower OS in both allogeneic (allo) and autologous (auto) HCT regardless of diagnoses, age, or conditioning. In contrast to the patients (pts) analyzed in the CIBMTR study, pts transplanted at Wake Forest more often have HCT ≥3. Methods We retrospectively analyzed data from pts transplanted from Sep 2014 to Sep 2016. 2-yr OS was observed for all pts. Results from 3 tools were used to compare predicted vs observed OS: HCT-CI, Disease Risk Index (DRI), and the CIBMTR survival calculator. Results Over 2 yrs, 216 pts were transplanted – 132 auto, median age 62 (26-78) and 84 allo, median age 55.5 (16-74). 59% of pts had a HCT-CI ≥3. In both groups, predicted and observed OS were not statistically different for those with HCT-CI 0. In contrast, predicted and observed OS for HCT-CI ≥3 were significantly different (p Conclusions Compared to the dataset utilized by the CIBMTR for validation of the HCT-CI, scores ≥ 3, largely accounted for by poor pulmonary function, are over represented in our population. Further analysis will need to be done to determine if the regional prevalence of poor pulmonary function is contributing to a significant difference in the predicted vs observed OS in our allo pts.

Patients with Acute Myeloid Leukemia (AML) have compromised marrow function and chemotherapy causes further suppression. As a result complications are frequent, and patients may require admission to the intensive care unit (ICU). How codes status changes when these events occur and how those changes influence outcome are largely unknown. Outcomes for adult patients with AML, undergoing induction chemotherapy, and transferred to the ICU between January 2000 and December 2013 were analyzed. 94 patients were included. Median survival was 1.3 months. At 3 and 6 months overall survival (OS) was 27% and 18% respectively. Respiratory failure was the most common reason for transfer to ICU (88%), with 63% requiring mechanical ventilation at transfer. Other reasons included: cardiac arrest (18%), septic shock (17%), hypotension (9%), and acute renal failure (9%). The most frequent interventions were mechanical ventilation in 85%, vasopressors in 62%, and hemodialysis in 30%. Following transfer 55 patients (58%) had a change in code status. Overall, 46 patients (49%) changed from Full Code (FC) to Comfort Care (CC), 7 (7%) from FC to Do Not Resuscitate (DNR), and 2 (2%) from DNR to CC. For the entire cohort, ICU mortality (IM) was 61% and hospital mortality (HM) was 71%. For FC or DNR patients, IM was 30% and HM was 41%. For CC patients, IM was 90% and HM was 100%. Overall, 27 patients (29%) survived to discharge. Of those discharged, 22 (81%) were alive at 3 months and 17 (63%) were alive at 6 months. In conclusion, patients that required ICU admission during induction chemotherapy have a poor prognosis. Code status changed during the ICU stay for the majority of patients and always to a less aggressive status.

Background This Phase 2 study tested the tolerability and efficacy of bortezomib combined with reinduction chemotherapy for pediatric patients with relapsed, refractory or secondary acute myeloid leukemia (AML). Correlative studies measured putative AML leukemia initiating cells (AML-LIC) before and after treatment.

Background: Acute myeloid leukemia (AML) is an aggressive myeloid cancer of the hematopoietic system that primarily affects older adults and is characterized by therapy resistance and dismal outcomes. Novel approaches to treat AML are desperately needed. Selinexor is a small-molecule inhibitor of the nuclear export protein XPO1. Treatment of AML cells with selinexor was shown to sensitize them to chemotherapy in part by blocking the nuclear export of topoisomerase II, resulting in increased DNA strand breaks when an anthracycline is present. Furthermore, selinexor has shown encouraging results when combined with chemotherapy in the relapsed setting. This abstract reports on the initial results of a randomized phase II study of induction and consolidation with or without selinexor in newly diagnosed patients with AML 60 years of age or older. Methods: Patients 60 years of age or older with newly diagnosed de novo AML were randomized between 7+3 or 7+3+selinexor induction. Responding patients could then go on to high dose cytarabine consolidation with or without selinexor as per their initial treatment assignment. Patients in the selinexor arm who completed all planned consolidation could then move to maintenance therapy with selinexor alone. During induction cytarabine was dosed at 100 mg/m2 by continuous infusion for 7 days and daunorubicin was dosed at 60 mg/m2 on days 1-3. In consolidation cytarabine was dosed at 1.5 gm/m2 given Q12 hours on days 1, 3 and 5. Selinexor was dosed at 60 mg PO on days 1, 3, 8, 10, 15 and 17 during induction and consolidation and on days 1 and 8 every 21 days in maintenance. Optional blood samples were collected just prior to and at several time points after selinexor during induction. Mononuclear cells were isolated from these samples, lysed and lysates evaluated for protein pathway drug target activation mapping by reverse phase phosphoprotein array (RPPA). Results: Thirteen patients have been enrolled to date with 12 available for evaluation. Of the 12 evaluable patients 6 were randomized to each arm. Baseline demographics are listed in Table 1. Overall the combination was well tolerated with no patients discontinuing selinexor secondary to treatment related adverse events. In the standard arm 3 of 6 patients achieved a complete remission. Of the 3 responders 1 has relapsed, 1 has gone on to transplant and one has completed consolidation chemotherapy. In the selinexor arm 5 of 6 patients achieved a complete remission and 1 patient achieved a morphologic leukemia free state. All patients given selinexor achieved a response. Of the 5 responders 3 have gone on to transplant, 1 is on maintenance therapy (completed 14 cycles) and one is completing consolidation therapy. In the standard arm no patients died during induction and 3 of 6 patients have died from progressive disease. In the selinexor arm 1 patient died during induction and none of the remaining patients have progressed (Figure 1 and Table 2). No difference in the AE profile was noted between arms and no unexpected side effects were observed. The patient on long term maintenance selinexor is tolerating it without significant AEs to date. Blood samples were available from 3 patients from the selinexor arm. RPPA based protein pathway activation mapping analysis of PBMCs revealed a significant increase in phosphorylation of AMPK, BAD and LC3B at one-hour post treatment that returned to baseline by 2 hours suggesting a transient increase in these pathways that was subsequently suppressed (Figure 2). Conclusions: Selinexor in combination with standard induction and consolidation therapy appears highly active in older de novo AML patients. Selinexor may increase response by modulation of AMPK, autophagy and BAD phosphorylation. Enrollment is ongoing. Disclosures Pardee: Spherix Intellectual Property: Research Funding; CBM Bipharma: Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau; Celgene: Speakers Bureau; Pharmacyclics/Janssen: Speakers Bureau; Karyopharm: Research Funding; Rafael Pharmaceuticals: Consultancy, Research Funding. Manuel:Novartis: Speakers Bureau; Jazz Pharmaceuticals: Speakers Bureau. Powell:Pfizer: Consultancy, Research Funding; Rafael Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau; Janssen: Research Funding. OffLabel Disclosure: Selinexor is not approved for the treatment of AML

Background. Acute myeloid leukemia (AML) is the most common acute leukemia in adults. The median age of diagnosis is 67 years old, and it has unfavorable outcomes in older patients. Approximately one-third of patients are diagnosed after the age of 75. Thus, as the population continues to increase in age, the incidence of AML will continue to expand (NCCN guidelines: AML. Version 3.2019). The long term disease free survival (DFS) rates for patients > 60 years of age is 5-15% whereas younger patients < 60 years of age have a better DFS rate of up to 40% (Dohner H, et al. N Engl J Med. 2015). Recent advancements have been made in patients with AML, including the approval of daunorubicin and cytarabine liposomal (Vyxeos®) for the treatment of adults with 2 poor risk types of AML: newly diagnosed therapy related AML (t-AML) or AML with myelodysplasia-related changes (AML-MRC). Given the financial constraints of this new medication, our objective was to determine the safety and efficacy of daunorubicin and cytarabine liposomal in our adult patients with t-AML and AML-MRC at a single academic medical center. Methods. This was a single center, retrospective, chart review at Wake Forest Baptist Health (WFBH) Comprehensive Cancer Center from August 1, 2017 to November 1, 2018. Patients were selected via report generation if they had received at least one dose of daunorubicin and cytarabine liposomal during the study period. The initial induction dose of daunorubicin and cytarabine liposomal was 44 mg/m2 of daunorubicin and 100 mg/m2 cytarabine administered on days 1, 3, and 5 for up to 2 cycles to achieve remission. If a second induction was necessary, the same induction doses were given on days 1 and 3 only. The consolidation dose was 29 mg/m2 of daunorubicin and 65 mg/m2 of cytarabine on days 1 and 3 for up to 2 cycles. The primary endpoint was overall survival (OS). Secondary endpoints included event free survival (EFS), 30-day and 60-day mortality, complete remission (CR) and morphologic complete remission with incomplete blood count recovery (CRi), adverse drug reactions, and financial impact to the health system. Descriptive statistics were utilized for demographic data. Time to event data was analyzed using the Kaplan-Meier method. SPSS IBM and Microsoft Excel Software were utilized for data analysis. Results. A total of 37 AML patients were identified as receiving daunorubicin and cytarabine liposomal from August 2017 to November 2018. Of those 37 patients, 27 had AML-MRC and 10 had t-AML. The average patient was a 70 year old Caucasian male with an ECOG performance status of 1 and a Charlson Comorbidity Index of 6 (Table 1). The median OS was 10 months and EFS was 7 months. The 30-day mortality rate was 16% and 60-day mortality rate was 19%. Eighteen patients (49%) achieved a CR and 2 patients (5%) achieved a CRi. A subgroup analysis was conducted for prior hypomethylating agent (HMA) use, age > 75 years old, < 60 years old, molecular mutations including FLT3-ITD and TP53 mutations, and t-AML. Poorer outcomes were noted in patients > age 75, prior HMA use, and the t-AML subgroups. Table 3 highlights the OS, 60-day mortality rate, transplant received and CR+CRi for each subgroup. The median time to platelet and absolute neutrophil count (ANC) recovery was 32 and 33 days, respectively. Eight patients (21.6%) proceeded to transplant post administration of daunorubicin and cytarabine liposomal. All patients experienced at least one adverse event with hematologic being the most commonly observed toxicity (Table 4). Most patients received induction therapy with daunorubicin and cytarabine liposomal in the inpatient setting whereas consolidation was predominantly administered in an outpatient encounter. Conclusions. Daunorubicin and cytarabine liposomal was considered an effective treatment option for patients with t-AML and AML-MRC with a CR+CRi rate of 54%. Younger patients (< 60 years old) exhibited the greatest benefit with an OS of 12 months and 60 day mortality rate of 0%. However, poorer outcomes were demonstrated in elderly patients (> 75 years old), patients with FLT3-ITD positive mutations, and patients with previous HMA use, with an OS less than 2 months in each subgroup and mortality rates ranging up to 60%. Thus, additional studies are necessary to determine the role of daunorubicin and cytarabine liposomal in these higher risk patient subgroups > age 75, FLT3-ITD positive patients, and patients with previous HMA use. Disclosures Manuel: Novartis: Speakers Bureau; Jazz Pharmaceuticals: Speakers Bureau. Pardee:Rafael Pharmaceuticals: Consultancy, Research Funding; Karyopharm: Research Funding; Spherix Intellectual Property: Research Funding; Pharmacyclics/Janssen: Speakers Bureau; Celgene: Speakers Bureau; Amgen: Speakers Bureau; CBM Bipharma: Membership on an entity's Board of Directors or advisory committees. Powell:Janssen: Research Funding; Rafael Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding.

Background. Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) accounting for approximately 10% of AML cases. Advancements in the management of APL have led to complete remission (CR) rates of 90-100% and 5-year overall survival (OS) rates between 86-97%. Standard treatment of APL consists of induction and consolidation, with or without post-consolidation therapy, which is directed by risk group, age, and cardiovascular risk. A standard consolidation option consists of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) (NCCN Guidelines, AML Version 3.2019). Frequently patients are unable to obtain consolidation with ATRA due to the high prescription co-pay and limited financial assistance. This study assessed the efficacy, safety, and financial impact of APL consolidation therapy with ATRA/ATO compared to ATO monotherapy at a single institution. Methods. This single-center, retrospective, chart-review study assessed adult patients with APL who received ATRA/ATO induction, followed by consolidation with ATRA/ATO or ATO monotherapy between November 2012 to January 2018. The primary efficacy endpoint was OS. Secondary endpoints included event-free survival (EFS), relapse-free survival (RFS), hematologic CR or molecular CR (CRm), incidence of adverse drug events, and outpatient accessibility of ATRA. Numerical data were expressed as medians and interquartile range (IQR) and categorical data were evaluated using the Fisher Exact test. The Log-rank test was used for time to event data and analyzed using the Kaplan-Meier method. A P-value of < 0.05 was defined as statistically significant. Results. The final analysis included 31 patients, 25 patients received standard ATRA/ATO and 6 patients received ATO monotherapy. Patients in the ATRA/ATO group had a median age of 47 years (range 19 - 72); 8 had low risk and 15 had intermediate risk APL. Patients in the ATO monotherapy group had a median age of 73 years (range 70 - 83); 4 had low risk and 1 had intermediate risk APL. Patients in the ATO monotherapy group had more comorbidities, with all patients having a Charlson Comorbidity Index of 4 or higher compared to only 44% of the ATRA/ATO group (p=0.02). A dose reduction for ATO was required for 50% and 28% of patients in the ATO monotherapy and ATRA/ATO groups, respectively due to peripheral neuropathy. During consolidation, patients in the ATO monotherapy group received a median of 5.4 mg/kg of ATO over 2 cycles compared to 11.6 mg/kg over 4 cycles in the ATRA/ATO group (Table 1). Five of six patients (83.3%) and 24 of 25 patients (96%) were alive at last follow-up in the ATO monotherapy and ATRA/ATO groups with a median follow-up of 33.3 months and 35.5 months, respectively (Graph 1). Secondary endpoints are provided in Table 2. There was 1 death in each group, both due to unknown causes. All adverse events occurred in a higher proportion of patients in the ATRA/ATO group (Graph 2). The incidence of headache was significantly higher in the ATRA/ATO group, occurring in 68% of patients and leading to ATRA discontinuation for 1 patient (Table 3), compared to 0 events in the ATO monotherapy group (p=0.004). Barriers to access occurred in 19.4% (6 of 31) of all patients. In addition to the 4 patients who required omission of ATRA upfront due to cost, 2 additional patients discontinued ATRA during consolidation due to affordability (Table 3). Conclusions. Patients in the ATO monotherapy group were on average older, had more comorbid conditions, and received a lower cumulative dose of ATO during consolidation. The standard dose of ATO during consolidation is 12 mg/kg administered over 4 cycles. In our study, patients in the ATO monotherapy group received a median of 5.4 mg/kg of ATO over 2 cycles compared to 11.6 mg/kg over 4 cycles in the ATRA/ATO group. Despite discrepancies in age, comorbidities, and total dose of ATO received, outcomes were similar in the ATRA/ATO and ATO monotherapy groups. Although limited by a small sample size and retrospective design, this study suggests that elimination of ATRA from consolidation may be an acceptable option for patients that are unable to obtain ATRA or that experience intolerable side effects. These findings also suggest that lower cumulative doses of ATO during consolidation may produce similar efficacy with lesser toxicity. Future large, multicenter studies are necessary to confirm the efficacy and safety of these findings. Table Disclosures Manuel: Novartis: Speakers Bureau; Jazz Pharmaceuticals: Speakers Bureau. Pardee:Rafael Pharmaceuticals: Consultancy, Research Funding; Karyopharm: Research Funding; Pharmacyclics/Janssen: Speakers Bureau; Celgene: Speakers Bureau; Amgen: Speakers Bureau; CBM Bipharma: Membership on an entity's Board of Directors or advisory committees; Spherix Intellectual Property: Research Funding. Powell:Rafael Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding; Janssen: Research Funding.

In patients undergoing autologous stem cell transplantation (aSCT), the recombinant human granulocyte colony-stimulating factor, filgrastim, has been historically utilized during mobilization. Filgrastim-SNDZ, a biosimilar of filgrastim, received landmark approval as the first biosimilar product approved by the FDA in the United States. Biosimilar products offer cost benefit over the reference product, while maintaining similar efficacy. As a result of the recent approval, our medical center made the conversion from using filgrastim to filgrastim-SNDZ as the preferred mobilizing agent to provide patients the same benefits at a reduced cost. The primary objective of this retrospective, observational cohort study was to assess the efficacy of filgrastim-SNDZ as a mobilizing agent in the SCT patient population compared to the formerly used reference product, filgrastim. The secondary objective was to confirm the cost savings associated with the conversion from filgrastim to filgrastim-SNDZ. Data was collected on two cohorts of patients undergoing mobilization prior to an aSCT who received either filgrastim or filgrastim-SNDZ. Efficacy was assessed based of the number of days of stem cell apheresis and number of CD34 stem cells collected during apheresis in both cohorts. Cost savings were assessed based on cost difference (average wholesale price) between the drug products. In total, 186 patients received an aSCT during this time frame. Sixty-nine patients were included in the filgrastim group and 78 were included in the filgrastim-SNDZ group. The difference in number of CD34 cells collected was not significant (p = 0.17). The median number of CD34 cells collected was 7.24 × 106 in the filgrastim group and 8.245 × 106 in the filgrastim-SNDZ group. The filgrastim-SNDZ group had a larger range of CD34 cells collected during apheresis than the filgrastim group. There was no statistically significant difference in number of CD34 cells collected between the groups in patients with multiple myeloma (p = 0.0969) or with non-Hodgkin's lymphoma (p = 0.976). Number of CD34 cells collected was also tested for non-inferiority with a non-inferiority margin of 0.73 (10%) and filgrastim-SNDZ was shown to be non-inferior in this outcome to filgrastim. The median number of days of apheresis was 2 in both groups and there was no significant difference in this outcome between the groups (p = 0.36). The cost comparison between groups showed significant cost savings with filgrastim-SNDZ. Annual cost savings is projected to be $92,000 for 93 patients receiving an average of 5 doses of filgrastim-SNDZ. This study shows that using filgrastim-SNDZ is an effective and cost savings option for mobilization prior to aSCT.

Introduction: Patients exposed to cytotoxic agents are at a higher risk of developing therapy related AML and MDS (tAML/tMDS), and have poor survival as compared to de novo AML due to high risk of adverse features. Secondary AML (sAML)includes patients with progression from myeloproliferative neoplasms (MPN) and myelodysplastic syndrome (MDS) to AML, considering this progression could be natural history of disease process. Patients with tAML are considered to have an inferior outcome compared with de novo AML. In this retrospective chart review study, we aimed to look at factors affecting the survival of tAML/tMDS, sAML and de novo AML. Method: This retrospective analysis included 219 AML patients treated at Wake Forest Baptist Medical Center between January 2010 and December 2016. Kaplan-Meier estimation was used to evaluate survival at one and two-year period in these three types of AML. Multiple Cox proportional hazards models were used to examine the interaction between baseline characteristics (Table 1) and AML type (tAML/tMDS, sAML, de novo AML) on survival. Backward selection method was used to identify important predictors for a final model. Hazard ratios and 95% CI of all-cause mortality were based on the final Cox model. Results: We analyzed 219 patients with AML diagnosis. Of those 151 (69%) were de novo AML, 25 (11%) sAML and 43 (20%) tAML/tMDS, with mean age of 60.7, 70.7, and 69.7 years respectively. 88% of sAML and 72% of tAML/tMDS were ≥ 65 years compared to 50% of de novo AML patients (p=0.0009). More patients were in underweight/normal BMI (< 24.9) category of sAML (50%) compared to 36% of de novo AML and 21% of tAML/tMDS although this was not statistically significant (p=0.10). There were more females with tAML/tMDS (51%) compared to de novo AML (48%) and sAML (40%) (p=0.52). Most patients in all three groups of AML were white with 79% of de novo AML, 88% of sAML and 88% of tAML/tMDS. Almost one-third of sAML (33%) and tAML/tMDS (38%) were in adverse risk category group with 24% of de novo AML in this category. Most of de novo (62%), sAML (67%) and tAML/tMDS (45%) were in intermediate risk category. There were 5 patients with tAML/tMDS in favorable risk category with zero sAML and 18 de novo AML in this category. 54% of our patients had ECOG performance score of 0-1. A majority of sAML (63%) had a positive smoking history compared to 47% of de novo AML and 44% of tAML/tMDS. Majority of patients in the three categories denied any alcohol use. Incidence of FLT-3 mutation was 23% in de novo AML, 0% in sAML and 9% in tAML/tMDS (p=0.0001). NPM1 mutation was present in 19% of de novo AML, none of sAML and 5% in tAML/tMDS (p = 0.0016). CEBPa mutation was present in 6% of de novo AML, 4% of sAML and 2% of tAML/tMDS. Median survival was 18.5 months for de novo AML (95% CI 14.9- 23.7), 7.2 months for tAML/tMDS (95% CI 3.3- 11.5) and 7.0 months for sAML (95% CI 3.4-15.6). The median survival was longer among males, compared to females with de novo AML (23.2 months in males; 95% CI 18.3-37.1 vs. 14.6 months in females; 95% CI 10.3-19.0) compared to sAML (13.5 months in males; 95% CI 3.8-55 vs, 3.3 months in females; 95% CI 0.2-8.1) and tAML/tMDS (6.3 months in males; 95% CI 4.5-17.8 vs. 7.2 months in females; 95% CI 2.3-11.5) p=0.06. Patients with adverse risk category had a shorter median survival compared to those with favorable risk category, especially in tAML/tMDS but this was not significant. After adjusting for age, risk category and FLT-3 status, the type of AML was not a significant predictor of survival. However, when compared with de novo AML, patients with sAML and tAML/tMDS appear to have a somewhat increased risk of death (HR 1.3; 95% CI 0.7-2.4 and 1.6; 95% CI 0.9, 2.7 respectively). Mortality was 4.5 (95% CI 1.8, 11.3) and 9.3 (95% CI 3.6, 24.0) times higher in patients with intermediate and adverse risk category respectively, when compared to the favorable risk group. Patients with positive FLT-3 had 1.6 times mortality compared to negative FLT-3 (95% CI 1.0, 2.7). Conclusion: We found that median survival was better in de novo AML compared to sAML and tAML/tMDS. There was no difference in survival between sAML and tAML/tMDS. Advancing age increases the odds of death across three types of AML. It is important to note that the effect of patient characteristics on survival is mostly consistent across the AML types and that once the major survival predictors are accounted for, the type of AML is no longer significant. Disclosures Pardee: Amgen: Speakers Bureau; Karyopharm: Research Funding; Novartis: Speakers Bureau; Celgene: Speakers Bureau; Rafael Pharmaceuticals: Employment. Powell:Rafael Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Background: Acute myeloid leukemia is an aggressive malignancy with poor outcomes especially in patients 60 years of age or older. This thought to be in part from increased resistance to chemotherapy in AML cells arising in an older host. One of the nine recognized biological hallmarks of aging is a decline in mitochondrial quality. The effect of exploiting this age-related metabolic vulnerability in relapsed AML has not been previously established. CPI-613 is a first-in-class agent that inhibits pyruvate dehydrogenase and α-ketoglutarate dehydrogenase, effectively impairing the TCA cycle. We have combined CPI-613 with high dose cytarabine and mitoxantrone in phase I and II clinical trials in over 100 patients with relapsed or refractory AML. Methods: To determine the effect of the addition of CPI-613 in older patients, the phase I and II datasets were combined and outcomes by age were analyzed and compared to age related outcomes in a historical dataset of patients treated with a high dose cytarabine, mitoxantrone and L-asparaginase but without CPI-613. In both trials, patients were given CPI-613 as a 2-hour infusion on days 1 through 5. Cytarabine was dosed at 3,000 mg/m² (if younger than 60) or at 1,500 mg/m² (if 60 years of age or older), given every 12 hours for 5 doses, starting on day 3 following the CPI-613 infusion. The mitoxantrone was dosed at 6 mg/m² and is given once daily following the first, third and fifth cytarabine doses. At day 14, nadir marrow was evaluated, and patients with residual disease could be re-treated as above or with an abbreviated 3-day cycle. Responding patients were eligible to receive up to 2 abbreviated 3-day consolidation cycles. The historical cohort was treated identically without CPI-613, except L-Asparaginase was given at a dose of 6,000 units/m2 following the last dose of cytarabine. Results: Patient characteristics are summarized in Table 1. In the historical dataset younger patients had a highly significant increase in median overall survival when compared to patients ≥60 years of age (figure 1A). In contrast, older and younger patients treated with CPI-613 in addition to the chemotherapy had no significant difference in median survival (figure 1B). Additionally, when outcome by dose of CPI-613 was analyzed, older but not younger patients had a significant improvement in survival when given a dose of 2,000 mg/m2 compared to those given 1,500 mg/m2 (figure 1C+D). Patients 60 years of age or older had a response rate of 55% and a median overall survival of 12.4 months when treated with a dose of CPI-613 of 2,000 mg/m2. Conclusions: Targeting mitochondrial metabolism exploits an age-related metabolic vulnerability in AML arising in older patients. These results have led to a randomized phase III trial of CPI-613 at 2,000 mg/m2 in combination with high dose cytarabine and mitoxantrone compared to high dose cytarabine and mitoxantrone alone in relapsed or refractory AML patients 60 years of age or older. Disclosures Pardee: Amgen: Speakers Bureau; Karyopharm: Research Funding; Celgene: Speakers Bureau; Rafael Pharmaceuticals: Employment; Novartis: Speakers Bureau. Ellis:Alexion: Speakers Bureau. Powell:Rafael Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Posaconazole is a triazole with broad spectrum of activity against multiple fungi including members of the fungal order Mucorales. This activity has been shown both in clinical and in vitro studies, which are critically reviewed here. It has become very popular in prophylaxis in acute myelogenous leukemia (AML) induction and in the graft-versus-host disease (GVHD) settings after 2 recent prospective trials that showed advantage of posaconazole prophylaxis compared to fluconazole or itraconazole. In this report, 2 patients are presented, in whom, despite posaconazole prophylaxis, invasive and ultimately fatal Rhizopus pulmonary infections developed. These cases are similar to a previously reported case of Rhizopus infection in a stem cell transplant recipient who also received posaconazole, indicating a potential newly recognized pattern of breakthrough infections in patients receiving posaconazole prophylaxis.

Polyomaviruses are increasingly recognized as important human pathogens. Among those, BK virus has been identified as the main cause of polyomavirus-associated nephropathy (PVAN), a major cause of renal allograft failure. PVAN has also been well described in the setting of non-renal solid organ transplantation. The reports of PVAN after hematopoietic stem cell transplantation (HCT) are surprisingly very few. Here, we describe a patient with treatment-related myelodysplastic syndrome who received an unrelated donor HCT after ablative conditioning and in vivo T cell depletion with alemtuzumab. He developed a biopsy-proven BK nephropathy, which contributed to his renal failure. Leflunomide as well as cidofovir were given at different times, both in combination with intravenous immunoglobulin. Both treatments were effective in reducing the BK viral load, the cystitis symptoms and both stabilized but did not really improved the renal function. The patient was still dialysis-dependent when he died from Pseudomonas sepsis 13 months after HCT. A critical review of the literature and the treatment modalities for post-HCT PVAN are provided.

Recent studies have described malignant stem cells as central to the initiation, growth, and potential relapse of acute and chronic myelogenous leukemia (AML and CML). Because of their important role in pathogenesis, rare and biologically distinct leukemia stem cells (LSCs) represent a critical target for therapeutic intervention. However, to date, very few agents have been shown to directly target the LSC population. The present studies demonstrate that parthenolide (PTL), a naturally occurring small molecule, induces robust apoptosis in primary human AML cells and blast crisis CML (bcCML) cells while sparing normal hematopoietic cells. Furthermore, analysis of progenitor cells using in vitro colony assays, as well as stem cells using the nonobese diabetic/severe combined immunodeficient (NOD/SCID) xenograft model, show that PTL also preferentially targets AML progenitor and stem cell populations. Notably, in comparison to the standard chemotherapy drug cytosine arabinoside (Ara-C), PTL is much more specific to leukemia cells. The molecular mechanism of PTL-mediated apoptosis is strongly associated with inhibition of nuclear factor κ B (NF-κB), proapoptotic activation of p53, and increased reactive oxygen species (ROS). On the basis of these findings, we propose that the activity of PTL triggers LSC-specific apoptosis and as such represents a potentially important new class of drugs for LSC-targeted therapy.

Human acute myelogenous leukemia (AML) is thought to arise from a rare population of malignant stem cells. Cells of this nature, herein referred to as leukemic stem cells (LSCs), have been documented for nearly all AML subtypes and appear to fulfill the criteria for stem cells in that they are self-renewing and give rise to the cells found in many leukemic populations. Because these cells are likely to be critical for the genesis and perpetuation of leukemic disease, the present studies sought to characterize unique molecular properties of the LSC population, with particular emphasis on the transcription factor, nuclear factor-κB (NF-κB). Previous experiments have shown that unstimulated human CD34+ progenitor cells do not express NF-κB. In contrast, primary AML CD34+ cells display readily detectable NF-κB activity as assessed by electrophoretic mobility shift assay and gene expression studies. Furthermore, detailed analyses of enriched AML stem cells (CD34+/CD38−/CD123+) indicate that NF-κB is also active in the LSC population. Given the expression of NF-κB in leukemic, but not normal primitive cells, the hypothesis that inhibition of NF-κB might induce leukemia-specific apoptosis was tested by treating primary cells with the proteasome inhibitor MG-132, a well-known inhibitor of NF-κB. Leukemic CD34+/CD38− cells displayed a rapid induction of cell death in response to MG-132, whereas normal CD34+/CD38− cells showed little if any effect. Taken together, these data indicate that primitive AML cells aberrantly express NF-κB and that the presence of this factor may provide unique opportunities to preferentially ablate LSCs.

Red blood cell (RBC) antigens represent inherited traits and as such, their expression should be constant throughout the life of an individual. We describe a patient in whom the expression of the Rh D and C antigens was lost due to the development of chronic myelogenous leukemia (CML). For this patient, this represented more than a blood bank curiosity but was of critical importance in determining further treatment of the leukemia. The mechanisms behind changes in RBC antigens due to malignancy are reviewed for a number of antigens, antigen systems, and antigen collections. Previous case reports of RBC antigen changes due to malignancy are summarized.

Recent studies suggest that the population of malignant cells found in human acute myelogenous leukemia (AML) arises from a rare population of leukemic stem cells (LSCs). LSCs have been documented for nearly all AML subtypes and have been phenotypically described as CD34+/CD38- or CD34+/HLA-DR-. Given the potentially critical role of these primitive cells in perpetuating leukemic disease, we sought to further investigate their molecular and cellular characteristics. Flow cytometric studies using primary AML tissue showed that the interleukin-3 receptor alpha chain (IL-3Ralpha or CD123) was strongly expressed in CD34+/CD38- cells (98 +/- 2% positive) from 16 of 18 primary specimens. Conversely, normal bone marrow derived CD34+/CD38- cells showed virtually no detectable expression of the CD123 antigen. To assess the functional role of IL-3Ralpha positive cells, purified CD34+/CD123+ leukemia cells were transplanted into immune deficient NOD/SCID mice. These experiments showed that CD123+ cells were competent to establish and maintain leukemic populations in vivo. To begin to elucidate a biological role for CD123 in leukemia, primary AML samples were analyzed with respect to signal transduction activity in the MAPK, Akt, and Stat5 pathways. Phosphorylation was not detected in response to IL-3 stimulation, thereby suggesting CD123 is not active in conventional IL-3-mediated signaling. Collectively, these data indicate that CD123 represents a unique marker for primitive leukemic stem cells. Given the strong expression of this receptor on LSCs, we propose that targeting of CD123 may be a promising strategy for the preferential ablation of AML cells.

Fifteen cancer patients, deemed blood HSC “mobilization failures” due to CD34+cell yields of 5-fold increases in CD34 + cell yields in the marrow compared to cytapheresis, and 4 patients had CD34 + cell yields of > 1.0 (i.e., 1.2, 1.44, 1.61 and 2.45)×106/kg from the primed marrow harvest. None of the five patients previously exposed to stem cell toxins or fludarabine achieved > 0.85×106/kg CD34 +cells with the primed marrow harvest. A significant difference was noted between G-CSF primed blood and marrow for CD34 + cells but not for GM-CFU (p = 0.011 and p = 0.135, respectively, paired t-test).All evaluable patients engrafted; a median ANC > 0.5×109/L recovery was achieved on D + 12 (range+9 to+17) in 12 of 13 evalua...

This trial tested the safety and efficacy of a regimen consisting of hydroxyurea followed by azacitidine, 75 mg/m(2) for 7 days, and gemtuzumab ozogamicin, 3 mg/m(2) on day 8, in older patients with newly diagnosed acute myeloid leukemia. Those achieving a complete remission received 1 consolidation treatment followed by 4 cycles of azacitidine. The patients were stratified into good-risk (age 60-69 years or performance status 0-1) and poor-risk (age ≥70 years and performance status 2 or 3) groups. Specific efficacy and safety goals were defined as being supportive of further study of the regimen. Eighty-three patients were registered in the good-risk cohort and 59 in poor-risk cohort, with median age of 71 and 75 years, respectively. In the good-risk group, 35 patients (44%) achieved a complete remission. Median relapse-free and overall survivals were 8 and 11 months, respectively. Six patients (8%) died within 30 days of registration. In the poor-risk group, 19 (35%) achieved a complete remission. Median relapse-free and overall survivals were 7 and 11 months, respectively. Seven patients (14%) died early. The results of this trial met predefined goals for efficacy and safety for the poor-risk cohort but not the good-risk group. .

We report the results of a phase I study with four dose levels of bortezomib in combination with idarubicin. Eligible patients were newly diagnosed with acute myeloid leukemia (AML) age ≥60 years, or any adult with relapsed AML. Bortezomib was given twice weekly at 0.8, 1.0, or 1.2 mg/m2 with once weekly idarubicin 10 mg/m2 for four weeks. Twenty patients were treated: 13 newly diagnosed (median age 68, range 61–83) and 7 relapsed (median age 58, range 40–77). Prior myelodysplastic syndrome (MDS) was documented in 10/13 (77%) newly diagnosed and 1/7 (14%) relapsed patients; the three newly diagnosed patients without prior MDS had dyspoietic morphology. Two dose-limiting toxicities occurred at the initial dose level (bortezomib 0.8 mg/m2 and idarubicin 10 mg/m2); idarubicin was reduced to 8 mg/m2 without observing subsequent dose-limiting toxicities. The maximum tolerated dose in this study was bortezomib 1.2 mg/m2 and idarubicin 8 mg/m2. Common adverse events included: neutropenic fever, infections, constitutional symptoms, and gastrointestinal symptoms. No subjects experienced neurotoxicity. Most patients demonstrated hematologic response as evidenced by decreased circulating blasts. Four patients (20%) achieved complete remission. There was one treatment-related death. The combination of bortezomib and idarubicin in this mostly poor-risk, older AML group was well tolerated and did not result in high mortality. This trial was registered at www.clinicaltrials.gov as # NCT00382954 .

Background: CPI-613 is a first in class agent that inhibits pyruvate dehydrogenase (PDH) and a-ketogluterate dehydrogenase. We have previously shown CPI-613 inhibits mitochondrial respiration, causes phosphorylation of PDH, activation of adenosine monophosphate activated kinase (AMPK) in AML cells and was well tolerated by patients with myeloid malignancies. Methods: We completed a phase I trial of CPI-613 in combination with high dose cytarabine (HiDAC) and mitoxantrone for relapsed or refractory AML patients. RNA sequencing analysis was conducted on a subset of patient samples to explore gene expression profiles associated with response. To explore genetic determinants of response, Cas-9 expressing AML cells were used to knock out p53 and AMPK. Results: In the phase I trial 67 patients were enrolled and 62 were evaluable. One patient died before completion of therapy, three died prior to the day 14 nadir marrow and one patient with accelerated phase CML was enrolled in error. The median age was 60 years (range 21-79). In patients with relapsed disease the median duration of CR1 was 11.2 months. Cytogenetics were poor risk in 27 patients, intermediate in 33, and good in 6. In the 62 evaluable patients the results were as follows. The overall response rate was 50% (26CR+5CRi) with a median survival of 6.7 months. Response was significantly associated with survival with a median survival of 13.2 months in responders compared to 3 months for all others. In patients ≥60 years old the CR/CRi rate was 47% (15/32) with a median survival of 6.9 months. This was not significantly different from patients younger than 60 years old. Surprisingly, the response rate for patients with poor risk cytogenetics was 46% (9CR+2CRi/24) with a median survival of 5.5 months. In a historical cohort, only 19% (3/16) of patients with poor risk cytogenetics responded with a median survival of 2.8 months (Figure 1). The most common toxicities of CPI-613 were diarrhea and nausea. Thirteen patients (21%) went on to allogeneic stem cell transplantation. Several patients had blood samples taken before and after CPI-613 infusion. Three of these patients had increased phosphorylation of PDH consistent with its inhibition. Additionally, two patients demonstrated a robust phosphorylation of AMPK consistent with preclinical studies. The role of AMPK in response was assessed by competition assays using Cas-9 expressing AML cells that have deleted AMPK. Normal cells out-competed AMPK deleted cells when treated with CPI-613 but not when treated with cytarabine, suggesting AMPK is a specific resistance factor against TCA cycle inhibition. To explore if loss of p53 function (common in poor risk cytogenetics) affected response we tested CPI-613 alone or with an anthracycline against an AML cell line with and without p53 knockdown. Suppression of p53 function resulted in significant resistance to anthracyclines but no change in response to CPI-613; the combination enhanced cell kill over either agent alone. To gain insight into the transcriptional programs that distinguish responders from non-responders prior to treatment, we sequenced the transcriptomes of mononuclear cells from 25 baseline patient samples: 19 from bone marrow and 9 from peripheral blood. These samples corresponded to 14 responders and 11 non-responders. Analysis for enrichment of gene ontologies revealed several significant biological categories for the genes overexpressed in responders, while none were identified for the non-responders. The responders showed significant enrichment for gene categories related to immune involvement, particularly genes associated with B lymphocytes. Conclusions: TCA cycle inhibition with CPI-613 is a promising novel approach in the treatment of AML patients, especially in the elderly and those with poor risk cytogenetics. Low levels of AMPK may identify patients with an increased likelihood of response. Finally, the presence of gene expression profiles consistent with immune cells raises the possibility that in addition to direct effects on leukemia cells, TCA cycle inhibition may alter microenvironment immune responses. Figure Kaplan-Meier curves of poor risk cytogenetic patients treated with CPI-613, HiDAC and mitoxantrone (CPI-HAM) compared to a historical cohort of patients treated with HiDAC, mitoxantrone and asparaginase (HAMA). Figure. Kaplan-Meier curves of poor risk cytogenetic patients treated with CPI-613, HiDAC and mitoxantrone (CPI-HAM) compared to a historical cohort of patients treated with HiDAC, mitoxantrone and asparaginase (HAMA). Disclosures Pardee: Cornerstone Pharmaceutical: Consultancy; Celgene: Speakers Bureau; Novartis: Speakers Bureau; Merck: Consultancy. Manuel:Novartis: Speakers Bureau.

Latexin is a negative regulator of hematopoietic stem cell number in mice. Its dysregulated expression in other tumors led us to hypothesize that latexin may have tumor suppressor properties in hematological malignancies. We found that latexin was down-regulated in a variety of leukemia and lymphoma cell lines as well as in CD34+ cells from the blood and marrow of patients with these malignancies. 5-aza-2′-deoxycytodine treatment and bisulfite sequencing revealed hypermethylation of latexin promoter in tumor cells. Retrovirus-mediated latexin overexpression in A20 mouse lymphoma cells inhibited their in vitro growth by 16 fold and in vivo tumor volume by 2 fold. Latexin caused growth inhibition of lymphoma cells by significantly increasing apoptosis through the down-regulation of anti-apoptotic genes Bcl-2 and Pim-2. The molecular mechanism underlying latexin-mediated tumor inhibition was not through its canonical carboxypeptidase inhibitor activity. These results are consistent with a tumor suppressor role for latexin and suggest that latexin may have clinical efficacy in the treatment of malignancies.

Previous studies indicate that human acute myelogenous leukemia (AML) arises from a rare population of leukemic stem cells. Cells of this nature can initiate and maintain leukemic cell growth in both long-term cultures and nonobese diabetic/severe combined immune-deficient mice. To characterize the biology of primitive AML cells, gene expression screens were performed with 7 primary AML and 3 normal specimens. For each sample, stem cell populations (CD34+/CD38−) were isolated and used to synthesize radiolabeled complementary DNA (cDNA). AML vs normal probes were then hybridized to cDNA arrays containing genes related to cancer and apoptosis. Of approximately 1400 genes analyzed, 2 tumor-suppressor genes were identified that were overexpressed in all 7 of the AML CD34+/CD38−cell populations: death-associated protein kinase and interferon regulatory factor 1. Expression of each gene was confirmed by reverse-transcription polymerase chain reaction and immunoblot analysis. It is proposed that tumor-suppressor proteins play a role in the biology of primitive AML cells.

Background: CPI-613 is a first in class agent that inhibits pyruvate dehydrogenase (PDH) and α-ketogluterate dehydrogenase. As a single agent CPI-613 was found to be well tolerated with possible activity in several patients with myeloid malignancies.This trial determined the maximum tolerated dose (MTD), safety, and efficacy of CPI-613 in combination with HDAC and mitoxantrone in patients with relapsed or refractory AML. Methods: CPI-613 was given daily on days 1 through 5 starting at a dose of 500 mg/m2. Beginning on day 3, HDAC at 3,000 mg/m2 (or 1,500 mg/m2 for age ≥60) is administered every 12 hours for 5 total doses and mitoxantrone at 6 mg/m2 is given daily for 3 doses. If residual disease is present on day 14 re-induction with the same or a three day abbreviated course could be given. Patients who achieved a complete remission with or without complete count recovery (CR or CRi) could receive up to a total of two additional consolidation cycles with the goal to get responders to stem cell transplant whenever possible. Results: A total of 67 patients have been enrolled and 65 are evaluable. The median age is 60 (range 21-79). Nineteen patients had refractory disease and 14 received at least 1 previous line of salvage therapy. In patients with relapsed disease the median duration of CR1 was 5 months. Cytogenetics were poor risk in 30 patients, intermediate in 30 and good in 6. One patient had CML in myeloid blast crisis. The overall intention to treat response rate was 48% (26CR+5CRi) with a median survival of 6.4 months. In patients ≥60 years old the CR/CRi rate was 42% (15/36). Surprisingly, the response rate for patients with poor risk cytogenetics was 47% (11CR+3CRi) with a median survival of 5.2 months. In a historical cohort treated with HDAC, mitoxantrone and asparaginase at our institution, only 19% (3/16) of patients with poor risk cytogenetics responded with a median survival of 2.8 months. The MTD of CPI-613 in combination with HDAC and mitoxantrone is 2,500 mg/m2. The dose limiting toxicities were diarrhea and nausea. Nine patients (13%) died on or before day 30. The most common toxicities attributed to CPI-613 were diarrhea and nausea, mainly grade 1 or 2. At the time of this submission thirteen patients have gone on to allogeneic stem cell transplantation. Several patients with circulating blasts had blood samples taken before and after CPI-613 infusion. Three of these patients had increased phosphorylation of PDH consistent with its inhibition. Additionally, two patients demonstrated a robust phosphorylation of adenosine monophosphate-activated protein kinase consistent with depletion of ATP. To explore if loss of p53 function (common in poor risk cytogenetics) affected response we tested CPI-613 alone or with an anthracycline against an AML cell line with and without p53 knockdown. Suppression of p53 function resulted in significant resistance to the anthracycline but no change in response to CPI-613; the combination enhanced cell kill over either agent alone. Conclusions: CPI-613 in combination with HDAC and mitoxantrone is a promising salvage regimen, especially in patients with poor risk cytogenetics. Disclosures Pardee: Novartis: Speakers Bureau; Celgene: Speakers Bureau. Off Label Use: CPI-613 is a novel anticancer agent not currently approved by the FDA. Ellis:Alexion: Speakers Bureau. Manuel:Novartis: Speakers Bureau. Hurd:Merck: Equity Ownership; Pfizer: Equity Ownership; Medtronic: Equity Ownership; Procter and Gamble: Equity Ownership; Bristol Myers Squib: Equity Ownership. Powell:Celgene: Speakers Bureau; Cornerstone Pharmaceuticals: Consultancy.

Background: Poor treatment tolerance contributes to suboptimal outcomes for many older adults with acute myeloid leukemia (AML). Treatment-associated physical deconditioning during induction may limit therapeutic options and impair quality of life. Interventions to enhance physical function during therapy may improve treatment tolerance and benefit. Objective: To test the feasibility of conducting a symptom-adapted inpatient physical activity (PA) intervention among older adults receiving intensive induction chemotherapy for AML. Methods: A single institution randomized controlled pilot study (N=70) was conducted from October 2012-July 2015. Eligibility included age ≥60 years, newly diagnosed AML, and receipt of induction chemotherapy. Exclusion criteria included medical contraindication to PA at the time of enrollment, cognitive impairment, and/or receipt of low intensity therapy. Participants randomized to the intervention were offered a PA session five days per week tailored daily to symptoms and health status during the induction hospitalization. Session options included: 1) Standard (ward-based), walking + balance training + resistance exercises; 2) Intermediate (room-based), upper-body ergometer + balance training + resistance exercises; and 3) Low-intensity (bed-based), upper-body ergometer + resistance exercises. Counseling sessions to establish PA goals and trouble-shoot barriers were conducted weekly during hospitalization. Phone counseling to reinforce PA goals continued monthly post-hospitalization during follow-up (up to 6 months). The control arm received usual care. Assessment of physical function (self-report and objective), mood, symptoms, and quality of life was done at baseline, 3 months and 6 months with weekly physical function testing while hospitalized. The primary outcome was feasibility defined as recruitment (≥60%), adherence (>75%, average 3 sessions/week), and retention (85% follow-up for eligible participants). Results: There were 97 eligible patients of which 70 enrolled (recruitment rate 72%). The study sample was 70% male, mean age was 72.1 years (Standard Deviation [SD] 6.3), mean Hematopoietic Cell Transplantation Comorbidity index score was 2.0 (SD 1.8), mean hemoglobin 9.3 (SD 1.6), mean white cell count 17 (SD 33.7), and 93% had adequate ECOG performance status (0-2). The majority had intermediate (61%) or poor (33%) risk cytogenetics. Most common induction regimens included anthracycline+cytarabine (80%) and clofarabine (15.7%). A total of 732 PA sessions were offered during the course of the study. Patients were deemed medically ineligible to participate in 13% of these sessions. Of eligible sessions, the participation rate was 80%. Of weeks with at least one eligible day, the average number of weekly sessions conducted per participant was 3.0 (SD 1.6). Overall mean number of sessions/participant was 14.5 (SD 9.4). Among the 35 participants randomized to the intervention 74% completed a program evaluation. Most reported that they liked the program (88%), found it helpful (88%) and planned to continue physical activity post discharge (69%). The activities rated to be most helpful were: combination of balance + resistance exercises + walking (31%), resistance exercises alone (23%) and balance exercises alone (15%). Retention was 96% among evaluable participants (survived at least to the 3 month follow-up assessment, N=53). Conclusions: Delivery of a symptom-adapted inpatient PA intervention to older adults receiving intensive induction chemotherapy for AML is feasible and well received by participants. Next steps include estimation of the effect size of the intervention on physical function, symptoms, and quality of life. Disclosures Pardee: Celgene: Speakers Bureau; Novartis: Speakers Bureau.

This study was conducted to define a new maximum tolerated dose and the dose-limiting toxicity (DLT) of melphalan and autologous hematopoietic stem cell transplantation (AHSCT) when used with the cytoprotective agent amifostine. Fifty-eight patients with various types of malignancy who were ineligible for higher-priority AHSCT protocols were entered on a phase I study of escalating doses of melphalan beginning at 220 mg/m(2) and advancing by 20 mg/m(2) increments in planned cohorts of 4 to 8 patients until severe regimen-related toxicity (RRT) was encountered. In all patients, amifostine 740 mg/m(2) was given on 2 occasions before the first melphalan dose (ie, 24 hours before and again 15 minutes before). AHSCT was given 24 hours after the first melphalan dose. Melphalan was given in doses up to and including 300 mg/m(2). Hematologic depression was profound, although it was rapidly and equally reversible at all melphalan doses. Although mucosal RRT was substantial, it was not the DLT, and some patients given the highest melphalan doses (ie, 300 mg/m(2)) did not develop mucosal RRT. The DLT was not clearly defined. Cardiac toxicity in the form of atrial fibrillation occurred in 3 of 36 patients treated with melphalan doses/=280 mg/m(2) and was deemed fatal in 1 patient given melphalan 300 mg/m(2). (Another patient with a known cardiomyopathy was given melphalan 220 mg/m(2) and died as a result of heart failure but did not have atrial fibrillation.) Another patient given melphalan 300 mg/m(2) died of hepatic necrosis. The maximum tolerated dose of melphalan in this setting was thus considered to be 280 mg/m(2), and 27 patients were given this dose without severe RRT. Moreover, 38 patients were evaluable for delayed toxicity related to RRT; none was noted. Tumor responses have been noted at all melphalan doses and in all diagnostic groups, and 21 patients are alive at median day +1121 (range, day +136 to day +1923), including 16 without evidence of disease progression at median day +1075 (range, day +509 to day +1638). Amifostine and AHSCT permit the safe use of melphalan 280 mg/m(2), an apparent increase over the dose of melphalan that can be safely administered with AHSCT but without amifostine. Further studies are needed not only to confirm these findings, but also to define the antitumor efficacy of this regimen. Finally, it may be possible to evaluate additional methods of further dose escalation of melphalan in this setting.

High-dose chemotherapy using melphalan (HDMEL) is an important component of many conditioning regimens that are given before autologous hematopoietic stem cell transplantation (AHSCT). In contrast to the situation in myeloma, and to a lesser degree acute leukemia, only a very limited published experience exists with the use of HDMEL conditioning as a single agent in doses requiring AHSCT for lymphoma, both Hodgkin lymphoma (HL) and especially non-Hodgkin lymphoma (NHL). Thus, we report results of treating 26 lymphoma patients (22 with NHL and four with HL) with HDMEL 220-300 mg/m(2) plus amifostine (AF) cytoprotection and AHSCT as part of a phase I-II trial. Median age was 51 years (range 24-62 years); NHL histology was varied, but was aggressive (including transformed from indolent) in 19 patients, indolent in two patients and mantle cell in one. All 26 patients had been extensively treated; 11 were refractory to the immediate prior therapy on protocol entry and two had undergone prior AHSCT. All were deemed ineligible for other, 'first-line' AHSCT regimens. Of these 26 patients, 22 survived to initial tumor evaluation on D +100. At this time, 13 were in complete remission, including four patients who were in second CR before HDMEL+AF+AHSCT. Responses occurred at all HDMEL doses. Currently, seven patients are alive, including five without progression, with a median follow-up in these latter patients of D +1163 (range D +824 to D +1630); one of these patients had a nonmyeloablative allograft as consolidation on D +106. Conversely, 14 patients relapsed or progressed, including five who had previously achieved CR with the AHSCT procedure. Two patients, both with HL, remain alive after progression; one is in CR following salvage radiotherapy. Six patients died due to nonrelapse causes, including two NHL patients who died while in CR. We conclude that HDMEL+AF+AHSCT has significant single-agent activity in relapsed or refractory NHL and HL. This experience may be used as a starting point for subsequent dose escalation of HDMEL (probably with AF) in established combination regimens.

Between April 1997 and March 1998 we evaluated the immune response and outcome in 11 chemosensitive patients who were treated with the anti-idiotype antibody vaccine TriAb after recovery from intensive therapy and autologous stem cell transplant (ASCT). Triab was commenced after recovery from the acute effects of ASCT; a minimum interval of 1 month was required from completion of consolidation radiotherapy, if given. Nine patients (82%) manifest anti-anti-idiotype antibody (Ab3) responses post ASCT. The maximal Ab3 response was seen after a median of 10 doses (range 5–20), which corresponded to a median of 14 months (range 5–19) post ASCT. Evidence of a T cell proliferative response was seen in eight patients; the response was modest in most of these. At a median follow-up of 24 months (range 22–33) after ASCT, four patients are alive without evidence of disease progression. All four of these patients were in the subgroup with more vigorous immune responses. Subsequent efforts have been directed toward the achievement of higher levels of immune responses more rapidly post ASCT. Bone Marrow Transplantation (2000) 26, 729–735.

Abstract 3584 Background: Increasing age and worsening performance status (PS) are associated with low complete remission (CR) rates and high early death rates in patients (pts) with acute myeloid leukemia (AML). Data from 4 SWOG trials show that in patients ≥70 and PS of ≥ 2, the CR rate with standard chemotherapy is 29% and 30-day death rate 48%. Preliminary data suggest that a regimen combining azacitidine (AZA) and gemtuzumab ozogamicin (GO) has significant activity and low toxicity in this group of patients. The current trial was designed to test this regimen in a larger group of patients in a cooperative group setting. Methods: Newly diagnosed pts, ≥60 years of age, with de novo or secondary non-M3 AML were treated as follows: Induction: Hydroxyurea 1500 mg twice daily till WBC Results: Data on 83 good risk pts were presented at ASCO 2012. The results presented here are from the poor risk cohort. A total of 54 poor risk pts were treated. Median age was 76 (70.3–87) and 33 were males. Five pts had pre-existing MDS. Of the 54 evaluable pts, 19 (35%) achieved a CR or CRi. One additional pt achieved a CR with continued AZA therapy after being removed from the study for persistent disease on D28. Median progression free survival is 7 mo and median overall survival 6 months. There were 31 grade 3 or 4 toxicities. Seven (14 %) pts died early, with a 30 day survival of 86%. An estimated 30% of the pts (in good risk and poor risk groups) were able to receive their induction therapy in the outpatient setting. Conclusions: The combination of hydroxyurea, azacitidine and GO is associated with lower induction mortality, can be given in the outpatient setting and results in a CR rate better than that seen in poor risk pts with AML treated with standard chemotherapy. These results are sufficiently encouraging to warrant further studies with this approach. Clinical Trials.govIdentifier: NCT00658814. Disclosures: Nand: Celgene: Research Funding.

Abstract 1223 Hematopoietic stem cells (HSCs) are currently used therapeutically to treat diseases such as leukemia; however, a greater understanding in both the molecular and environmental requirements for HSCs self-renewal will hopefully increase the success rate of these therapeutic uses. It is increasingly evident that reactive oxygen species (ROS) and cellular oxidative stress play an important role in HSC self-renewal and differentiation. Therefore a better understanding of intracellular oxidative stress regulation is critical to increasing transplant success and increasing successful treatment of Leukemia. Our studies take aim at determining the role of multidrug resistance-associated protein 1 (MRP1) in regulating intracellular ROS in HSC's. MRP1 is expressed at slightly higher levels in HSCs than in mature blood cells. The expression pattern of MRP1 in HSCs suggests a possible role in hematopoietic stem cell integrity and differentiation. A major function of MRP1 is to help maintain the oxidative balance of the cell by transporting reduced glutathione (GSH), oxidized glutathione (GSSG), and glutathione-4-hydroxy-nonenal (HNE-SG) conjugates out of the cell. We have hypothesized that MRP1-dependent efflux of GSH and GSSG in HSC increases intracellular reactive oxygen species (ROS) resulting in a loss of self-renewing and increased differentiation of HSCs. In our current studies we have used C57BL/6 FVB and Mrp1-disrupted FVB [Mrp1 (−/−)] mice to investigate the role of MRP1 in HSC differentiation. Our experiments have revealed an increase in LT-HSC and ST-HSC and a corresponding decrease in MPP's in the MRP1 −/− mice as compared to WT matched controls. To determine if MRP1 plays a role in regulating HSC intracellular oxidative stress levels via GSH and GSSG efflux, we measured cellular oxidative stress as a function of DCF-DA and relative GSH levels as a function of glutathione-monochlorobimane (GS-MCB) conjugate fluorescence by flow cytometry. Our studies revealed higher intracellular ROS in WT mice as compared to MRP1 −/− mice and decreased GS-MCB in our WT mice as compared to the MRP1 −/− mice. Taken together the DCF-DA and MCB assays support our hypothesis that MRP1-dependent efflux of GSH/GSSG decreases cellular GSH resulting in higher level of ROS. Our hypothesis is further supported by analysis of lineage marked cells (Lin+), which showed a distinct differentiation pattern between the cells derived from WT and MRP1−/− bone marrow (BM). These studies are supported by results from colony forming cell (CFC) assays. Interestingly, analysis of whole blood did not result in a robust phenotype with regards to leukocytes; however, we found an increase in the number of platelets in MRP1−/− mice when compared to the WT. The increase in platelets is an intriguing result under further investigation. In light of our recent results we have initiated long-term transplant assays to determine if MRP1 does indeed play a role in HSC differentiation and self-renewal. If our hypothesis is true as suggested by our current studies then we expect that expression of MRP1 will negatively effect the ability of HSC's to successfully transplant in the long-term. Overall our data supports our hypothesis that MRP1-dependent efflux of GSH and GSSG in HSC increases intracellular ROS thereby decreasing HSC self-renewing potential and increasing HSC differentiation. Disclosures: No relevant conflicts of interest to declare.

Abstract 1624 Tumor suppressor gene silencing via mechanisms including DNA hypermethylation is a recognized event in lymphomagenesis and lymphoma recurrence and transformation. DNA methyltransferase inhibitor, azacitidine, reduces epigenetic methylation in lymphoma and numerous other tumor models. Given the poor outcome of patients with transformed or refractory lymphoma, there is an immediate need to find novel therapies. We report the first results of an ongoing Phase I trial evaluating the maximal tolerated dose (MTD) of azacitidine given in a schedule intended to sensitize lymphoma to a regimen of oral cyclophosphamide, intravenous vincristine, and rituximab (for those patients whose lymphoma expresses CD20) for patients with recurrent or refractory lymphoma. Participants receive azacitidine (days 1–5, starting with 25 mg/m2) followed by oral cyclophosphamide (days 6–9, 300 mg/m2), vincristine (day 8, 1.4 mg/m2, maximum of 2 mg), and rituximab (day 8, 375 mg/m2). All patients receive pegfilgrastim (day 10, 6 mg) with each cycle. Cycles are repeated every 21 days for up to eight cycles if participants continue to benefit from therapy. To determine the MTD, a “3+3” design was employed. Dose limiting toxicity (DLT) is assessed during cycle 1. DLT is defined as the following: grade 3 or 4 non-hematologic toxicity (excluding emesis or isolated elevation of alkaline phosphatase); grade 4 neutropenia or thrombocytopenia of ≥7 days duration; increased serum creatinine > 2.0 times upper limit of normal; inability to receive all doses of azacitidine or cyclophosphamide within the first cycle or inability to initiate cycle 2 within two weeks of completing cycle 1 due to drug-related toxicity. Of the first 10 patients enrolled (8 patients in 25 mg/m2 azacitidine cohort, and 2 patients in 50 mg/m2 cohort), median age was 56 years (range 39–73). Median number of prior lines of therapy was 3 (range 2–4). Lymphoma subtypes included diffuse large B cell lymphoma (DLBCL; n=4), follicular lymphoma (FL; n=3), Hodgkins lymphoma (HL; n=1), small lymphocytic lymphoma (SLL; n=1), and cutaneous T-cell lymphoma (CTCL; n=1). A median of 2 cycles (range 1–6) have been received. The MTD has not yet been reached. One patient experienced thrombocytopenia as a DLT. The DLT criteria were subsequently revised to allow grade 4 thrombocytopenia of < 7 days after initially noting that some patients experienced asymptomatic grade 4 thrombocytopenia lasting only a short duration. An additional three patients were accrued to the first dose level after this adjustment to the current DLT, with no additional patients experiencing a DLT. Grade 3–4 toxicities during any cycle of therapy were as follows: neutropenia (n=5); thrombocytopenia (n=4); anemia (n=2); and abscess, anorexia, bacteremia, hypoalbuminemia, and nausea (n=1 each). Additionally, grade 3 cardiac ischemia and deep venous thrombosis each occurred in one patient but were considered unrelated to treatment by the investigator. Of the 8 patients who have completed treatment, 1 patient with FL achieved a complete response (CR), 1 patient with FL achieved a partial response (PR), 2 had stable disease (SD), 2 experienced progressive disease (PD), and 2 were not evaluable (NE) for response. Interestingly, the CR was maintained for 7 months and the PR has been ongoing for 6 months since completion of therapy. These preliminary data suggest the therapeutic potential of this novel combination and enrollment remains ongoing to define the MTD. Additional correlative assessments of tumor and peripheral blood mononuclear cells are also underway. Disclosures: Off Label Use: Azacitidine is the test article in this study and is not FDA approved for the treatment of lymphoma. Hayslip:Celgene: Research Funding.