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This master's thesis is a case study of sixteen black-and-white photographs of tuberculosis treatment facilities in Rochester, N.Y., by local photographer Albert R. Stone. They appeared in the Rochester Herald in as two photo essays, one in 1909 and the other in 1923. The aim of my research was to provide contextual information about Albert Stone and the Rochester Herald, tuberculosis and its treatment, and how the disease was portrayed photographically, and ultimately, to determine whether Stone's photographs were typical of tuberculosis-related images. I examined them in the context of other sanatorium images and based on statements about the conventions of sanatorium photographs made by Daniel M. Fox and Christopher Lawrence in Photographing Medicine: Images and Power in Britain and America Since 1840, and concluded that they were representative of photographs of sanatoriums made in the early twentieth century.

Despite recent advances in therapeutic approaches, patients with MLL-rearranged leukemia still have poor outcomes and a high risk of relapse. Here, we found that MLL-AF4, the most common MLL fusion protein in patients, transcriptionally induces IGF2BP3 and that IGF2BP3 strongly amplifies MLL-Af4 mediated leukemogenesis. Deletion of Igf2bp3 significantly increases the survival of mice with MLL-Af4 driven leukemia and greatly attenuates disease, with a minimal impact on baseline hematopoiesis. At the cellular level, MLL-Af4 leukemia-initiating cells require Igf2bp3 for their function in leukemogenesis. eCLIP and transcriptome analysis of MLL-Af4 transformed stem and progenitor cells and MLL-Af4 bulk leukemia cells reveals a complex IGF2BP3-regulated post-transcriptional operon governing leukemia cell survival and proliferation. Regulated mRNA targets include important leukemogenic genes such as those in the Hoxa locus and numerous genes within the Ras signaling pathway. Together, our findings show that IGF2BP3 is an essential positive regulator of MLL-AF4 mediated leukemogenesis and represents an attractive therapeutic target in this disease.

Chromosomal rearrangements of the mixed-lineage leukemia (MLL) gene are observed in acute lymphoblastic leukemias (ALL), acute myeloid leukemias (AML), and in rare mixed-lineage leukemia. Despite recent progress in therapeutic approaches, patients with MLL-rearranged (MLLr) leukemias still have very poor outcomes and a high risk of relapse. Of more than 90 fusion partner genes, MLL-AF4 is the most common MLL fusion protein in patients. Previously, we found that the RNA binding protein IGF2BP3 was specifically overexpressed in MLL-rearranged B-ALL, and enforced expression in vivo led to a pathologic expansion of hematopoietic stem and progenitor cells resulting in B and myeloid cell leukocytosis in the periphery. However, the requirement of IGF2BP3 in MLL-AF4 mediated leukemogenesis remains to be determined. Utilizing our previously generated list of differentially regulated targets with IGF2BP3 knockdown and a published dataset of MLL-Af4 targets, we determined that transcripts modulated by IGF2BP3 showed significant enrichment for MLL-Af4-bound genes. Furthermore, we observed that MLL-AF4 directly binds to and transcriptionally induces IGF2BP3. We performed ChIP-PCR assays on RS4;11 and SEM cell lines, human B-ALL cell lines that carry the MLL-AF4 translocation, and determined that the region in the first intron of IGF2BP3 is strongly bound by MLL-AF4. Furthermore, we observed a dose-dependent increase in luciferase reporter activity when we co-transfected a dual-luciferase reporter vector containing the promoter region of IGF2BP3 with increasing levels of MLL-AF4 expressing retroviral vector. To determine the role of Igf2bp3 in MLL-Af4 driven leukemogenesis, we generated the first Igf2bp3 KO murine model. Surprisingly, Igf2bp3 KO mice maintain normal, steady-state hematopoiesis. However, in striking contrast, deletion of Igf2bp3 in the MLL-Af4 leukemia model, significantly increases the survival of MLL-Af4 transplanted mice and greatly attenuates the disease. Furthermore, Igf2bp3 deficiency significantly reduced the tumor burden and disease severity. We observed significant decreases in WBC counts, spleen weights, and infiltrating leukemic cells visualized in histopathological analysis of hematopoietic tissues and quantified by FACS analysis. Moreover, deletion of Igf2bp3 led to a leukemia-initiating cell (LIC) disadvantage in vivo, demonstrated by significantly reduced engraftment in primary transplanted mice and reconstitution of secondary serially transplanted mice. To identify the transcripts directly regulated by Igf2bp3 in the context of MLL-Af4 driven leukemia, we carried out enhanced crosslinking and immunoprecipitation (eCLIP) transcriptome analysis of MLL-Af4 transformed early stem and progenitor cells and primary cells purified from splenic tumors of MLL-Af4 leukemic mice. We discovered an IGF2BP3-regulated post-transcriptional operon governing leukemic cell survival and proliferation, in which mRNA targets include the Hoxa locus and numerous genes within the Ras signaling pathway. In our study, we provide evidence that Igf2bp3 is required for the initiation of MLL-Af4 driven leukemia. We determined that Igf2bp3 is necessary for the development of and function of MLL-Af4 LICs. Mechanistically, we show that Igf2bp3 binds to and modulates the expression of hundreds of critical target transcripts. In summary, we demonstrate that Igf2bp3 is a positive regulator of MLLr leukemogenesis by targeting Hoxa transcripts such as Hoxa9 and numerous Ras signaling pathway transcripts, thereby controlling multiple downstream effector pathways required for disease initiation and aggressiveness. Together, our findings identify IGF2BP3 as an important, potential therapeutic target in this disease. Disclosures No relevant conflicts of interest to declare.

Summary This study aimed to describe the patterns of care and outcomes of diffuse large B cell lymphoma (DLBCL) after failure of front line anthracycline-based immunochemotherapy (IC). Patients with newly diagnosed lymphoma were prospectively enrolled in Molecular Epidemiology Resource (MER) of the University of Iowa/Mayo Clinic Lymphoma Specialized Program of Research Excellzence. All DLBCL and primary mediastinal B-cell lymphoma (PMBL) patients treated with front-line anthracycline-based IC were followed for relapse. Patients with relapse on follow-up and subsequently retreated were included in this analysis. 1039 patients received anthracycline-based IC between 2002 and 2012, of which 244 relapsed and were subsequently retreated. Across all therapies, overall survival at 4 years (OS4) from relapse was 28% and 103 patients ultimately underwent autologous haematopoietic cell transplant (autoHCT) with OS4 from autoHCT of 51%. Patients relapsing after 12 months from initial diagnosis had OS4 of 47% but those with a transient or no response to initial therapy had OS4 of only 13%. Outcomes of relapsed or refractory DLBCL differ substantially when categorized by response to initial therapy, timing of relapse and opportunity to undergo autoHCT. The design and interpretation of uncontrolled trials should account for this heterogeneity in patients with relapsed DLBCL.

Background aims Adoptive immunotherapy with the use of chimeric antigen receptor (CAR)-engineered T cells specific for CD19 has shown promising results for the treatment of B-cell lymphomas and leukemia. This therapy involves the transduction of autologous T cells with a viral vector and the subsequent cell expansion. We describe a new, simplified method to produce anti-CD19-CAR T cells. Methods T cells were isolated from peripheral blood mononuclear cell (PBMC) with anti-CD3/anti-CD28 paramagnetic beads. After 2 days, the T cells were added to culture bags pre-treated with RetroNectin and loaded with the retroviral anti-CD19 CAR vector. The cells, beads and vector were incubated for 24 h, and a second transduction was then performed. No spinoculation was used. Cells were then expanded for an additional 9 days. Results The method was validated through the use of two PBMC products from a patient with B-cell chronic lymphoblastic leukemia and one PBMC product from a healthy subject. The two PBMC products from the patient with B-cell chronic lymphoblastic leukemia contained 11.4% and 12.9% T cells. The manufacturing process led to final products highly enriched in T cells with a mean CD3+ cell content of 98%, a mean expansion of 10.6-fold and a mean transduction efficiency of 68%. Similar results were obtained from the PBMCs of the first four patients with acute lymphoblastic leukemia treated at our institution. Conclusions We developed a simplified, semi-closed system for the initial selection, activation, transduction and expansion of T cells with the use of anti-CD3/anti-CD28 beads and bags to produce autologous anti-CD19 CAR–transduced T cells to support an ongoing clinical trial.

Importance The University of Michigan has investigated the use of induction selection (IS) with chemoradiotherapy (CRT) for patients who respond to CRT and found this approach effective in the management of advanced laryngeal cancer. The IS approach was extended to oral cavity squamous cell carcinoma (OCSCC) to help understand whether organ preservation or survival benefit resulted. Objective To evaluate the efficacy of an IS protocol vs primary surgical extirpation and selective postoperative radiotherapy for advanced OCSCC. Design and Setting Retrospective matched cohort study at a tertiary care hospital. Participants Nineteen patients with resectable stages III and IV OCSCC were enrolled into a phase 2 IS trial. Patients with a response of at least 50% underwent concurrent CRT; those with a response of less than 50% underwent surgical treatment and radiotherapy. A comparison cohort of patients treated with primary surgical extirpation during a similar time period was frequency matched for inclusion criteria and patient characteristics to those patients included from the phase 2 IS trial. No difference was noted in age, sex, pretreatment American Joint Committee on Cancer stage, T and N classifications, smoking status, alcohol consumption, or tumor subsite between the IS and surgical cohorts. Median follow-up was 9.4 years in the IS cohort and 7.1 years in the surgical cohort. Interventions Induction selection and CRT vs primary surgical extirpation with or without postoperative radiotherapy. Main Outcomes and Measures Overall and disease-specific survival and locoregional control. Results The Kaplan-Meier estimate for overall survival at 5 years was 32% in the IS cohort and 65% in the surgical cohort. The Kaplan-Meier estimate for disease-specific survival at 5 years was 46% in the IS cohort and 75% in the surgical cohort. The Kaplan-Meier estimate for locoregional control at 5 years was 26% in the IS cohort and 72% in the surgical cohort. Multivariable analysis demonstrated significantly better overall and disease-specific survival and locoregional control outcomes ( P = .03, P = .001, and P Conclusions and Relevance Primary surgical treatment showed significantly better survival and locoregional control compared with IS in this matched patient cohort. Despite success of organ preservation IS protocols in the larynx, comparative survival analysis of an IS protocol vs primary surgical extirpation for OCSCC demonstrates significantly better outcomes in the surgical cohort. These findings support surgery as the principal treatment for OCSCC.

Background: Adult T-cell acute lymphoblastic leukemia / lymphoma (T-ALL) is a rare and aggressive hematological malignancy. Unlike B-cell ALL, apart from age and presenting WBC, additional prognostic factors remain largely unknown. Additionally, the prognostic impact of a monosomal karyotype, which has a negative impact on survival in myeloid neoplasms, remains to be determined in T-ALL (Kenderian et al, BCJ 2013) Aim: To study predictors of survival including the role of a monosomal karyotype in T-ALL. Methods: After due IRB approval, adults diagnosed with T-ALL from 1990-2014 at Mayo Clinic Rochester were identified. All clinical and pathologic data including FISH studies and cytogenetics were retrospectively reviewed. Chi-square test was used to compare variables. Survival was estimated and compared using the Kaplan-Meier Method and log-rank test. Univariate and multivariate analysis was performed using the Cox regression model. Results: Between 1990 and 2014, a total of 92 consecutive patients (pts) with T-ALL were identified, 41 had acute lymphoblastic lymphoma (LBL), and 51 (55%) acute lymphoblastic leukemia (ALL). Median age at diagnosis was 33 years (range; 18-88 years) with 72%males. Median follow up of our cohort was 25 months (range; 0.9-260 months) during which time 42 deaths (45%) were documented. A. Baseline characteristics: Fifty six (67%) had constitutional symptoms, and 63 (77%) had lymphadenopathy at diagnosis. Mediastinal mass was identified in 49 (55%) pts with palpable splenomegaly in 16 (20%) pts. Fifty one (58%) pts had extranodal disease, and 17 (19%) pts had CNS involvement. Pleural and pericardial effusion were evident in 16 (19%), and 6 (7%) pts, respectively. Median laboratory values included; LDH 288 U/L (115-6590), hemoglobin (Hb) 12.8 g/dl (4.5-18.2), WBC 8.65 x109 (1.4-406), platelets 169 x109 (8-485), bone marrow blasts 29% (0-99). B. Treatments: Induction therapies were variable and included; 11 (12%) CHOP like regimens, 7 (8%) modified NHL regimens (Asparginase+CHOP), 54 (58%) ALL like regimens (CALGB 9111, E2993, or HyperCVAD), 13 (14%) Pediatric regimens (ALL 10403, CCG 1961, BFM, Augmented BFM, GRAALL 2003, or Hoelzer regimen), with 7 (8%) patients' receiving palliative care only. Seventy-one (77%) pts achieved complete remission (CR1) during induction therapy while eight pts had refractory disease (8%). Thirty-three (35%) pts underwent stem cell transplant; 7 (21%) autologous and 26 (79%) allogeneic. Forty one (44%) pts had disease relapse and median time to relapse was 10.8 months (range; 8.2-16 months) C. Predictors of survival: In univariate analysis, that included age > 60 years, leukocyte count Hb, Plt, Blast percentage, mediastinal mass, LDH and CNS involvement, only age >60 and CNS involvement were predictors of inferior survival and both retained significance in the multivariable analysis with HR 3.9 (CI 1.5 - 9; p=0.0055) and 2.8 (1.3 - 5.7; p =0.0085), respectively (Figure 1 and 2). In this cohort age >60 was a better stratification that the conventionally used age above 40 (p = 0.1). Among 56 pts with evaluable cytogenetics data, 7 (13%) pts had MK which did not have an impact on survival with HR 1.9 (CI 0.4-5.6; p=0.33). Conclusion: In this large cohort of adult T-ALL patients, we observed that age >60 years and CNS involvement were independent predictors of inferior survival. MK was infrequent, but unlike in myeloid neoplasms, does not seem to impact overall survival. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding. Witzig:Novartis: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Spectrum: Research Funding; Valeant Pharma: Equity Ownership.

Background: Diffuse large B-cell lymphoma (DLBCL) is curable for the majority of patients treated with anthracycline based immunochemotherapy (IC). However, up to 40% of patients will relapse or require retreatment of DLBCL and outcomes are poor in this setting. Here we examine the incidence, treatment patterns and outcomes of relapsed DLBCL in the R-CHOP era. Methods: Patients were prospectively enrolled in the University of Iowa / Mayo Clinic SPORE Molecular Epidemiology Resource (MER) within 9 months of diagnosis and followed for relapse, retreatment, and death. Clinical management at diagnosis and subsequent therapies were per treating physician. This analysis includes patients with DLBCL or primary mediastinal B-cell lymphoma (PMBCL) who underwent front-line anthracycline based IC; patients with primary CNS lymphoma or PTLD were excluded. All relapse and re-treatments were verified by medical record review. Response to front-line therapy was retrospectively classified per 2007 Revised Response Criteria for Malignant Lymphoma from available clinical and radiology records. Unplanned consolidative radiation (RT) without biopsy proven disease after achieving PR from IC (N=21) was not classified as a relapse. Results: 1039 patients with newly diagnosed DLBCL or PMBCL and treated with IC were enrolled in the MER from 2002-2012. Median age at diagnosis was 62 years (range 18-92) and 577 patients (56%) were male. 647 patients (63%) had stage III/IV disease and IPI at diagnosis was 0-1 in 350 patients (34%), 2 in 305 patients (29%), 3 in 250 patients (24%) and 4-5 in 134 patients (13%). At a median follow-up of 59 months (range 1-148), 258 patients had relapse or retreatment of DLBCL of which 184 (71%) died. Incidence of relapse was 21.7% (95% CI: 19.3%-24.4%) at 2 years and 25.5% (95% CI: 22.9%-28.5%) at 5 years. In addition, the incidence of lymphoma related death without documented relapse or retreatment was 4.7% (95% CI: 3.6%-6.2%) at 2 years. At first relapse, 174 patients (67% of relapsed) received platinum based salvage therapy with 90 (52%) subsequently proceeding to autologous stem cell transplant (ASCT). 22 patients received CNS directed systemic therapy at relapse with 9 (41%) proceeding to transplant, and 43 received non-platinum-based salvage systemic therapy with 7 proceeding to transplant (17%), 15 patients received RT only as 2nd line therapy, and 4 were untreated. At a median follow-up of 56 months (range 6-121) post-transplant, 39 of 107 patients who underwent transplant remain in remission with a 2-year post-transplant progression-free survival of 45% (95% CI 37%-56%). Response to front-line IC was predictive of post-relapse outcome. Survival post-relapse was superior in the 162 patients with responsive disease (CR or PR) at the end of front-line IC (median OS 21.0 months) compared to the 88 patients who had stable or progressive disease (median OS 6.8 months, HR = 2.33, 95% CI: 1.73-3.14 p 60 (HR =1.51, 95% CI: 1.12-2.03, p=0.0064). There was no difference in survival at first relapse by cell of origin (HR = 1.13, 95% CI: 0.74-1.72, p=0.59). Conclusions: Most patients undergo therapy after relapsed/refractory DLBCL but only one-third receive ASCT. Outcomes following all treatments for relapsed/refractory DLBCL remain poor. Factors associated with adverse outcomes include refractory to front-line therapy, early relapse, baseline IPI and advanced age. These outcomes provide relevant historical control for the many novel agents being tested in this unmet need. Figure 1. Figure 1. Disclosures Farooq: Kite Pharma: Research Funding. Maurer:Kite Pharma: Research Funding. Cerhan:Kite Pharma: Research Funding. Link:Genentech: Consultancy, Research Funding; Kite Pharma: Research Funding. Thompson:Kite Pharma: Research Funding.

Background. Diffuse large B-cell lymphoma (DLBCL) is curable for the majority of patients treated with anthracycline based immunochemotherapy (IC). While most patients achieve response to initial therapy, a subset of patients are refractory to initial IC or become refractory to subsequent salvage therapies. Prognosis in this setting is very poor. Here we determine the incidence of refractory disease from a large cohort of DLBCL prospectively followed from diagnosis in the IC era and assess outcomes in these patients. Methods. Patients were prospectively enrolled in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) within 9 months of diagnosis. Patients were followed for relapse, retreatment, and death; all events were validated by medical record. This analysis includes patients with DLBCL or primary mediastinal B-cell lymphoma (PMBCL) who received initial treatment of anthracycline based immunochemotherapy; patients with primary CNS lymphoma or post-transplant lymphoproliferative disorders were excluded. Response to therapy was retrospectively classified per 2007 Revised Response Criteria for Malignant Lymphoma from available clinical and radiology records. Refractory disease was defined as having a best response to any systemic therapy of stable disease (SD), progressive disease (PD), or relapse within 12 months of autologous stem cell transplantation (SCT). We also examined patients with transient response to IC as defined by achieving an interim response (CR or PR) but having progressive disease at or prior to the end of the planned number of cycles of IC. Results. 1039 patients with DLBCL or PMBCL lymphoma were enrolled in the MER from 2002-2012 and treated with R-CHOP or comparable IC. Median age at diagnosis was 62 years (range 18-91) and 577 (56%) were male. At a median FU of 60 months (range 1-148), 136 patients developed refractory disease. The median age at diagnosis of patients with refractory disease was 62 years (range 19-87). The cumulative incidence of refractory DLBCL was 11.3% at 2 years (95%: CI: 9.5-13.4) and 13.1% at 5 years (95% CI: 11.2-15.4). The median overall survival after becoming refractory was 4.7 months (95% CI: 4.1-5.5) with a 1 year survival rate of 21% (95% CI: 15%-30%). The median number of therapies before becoming refractory was 2 with 35 patients becoming refractory following their first therapy (i.e. IC), 83 patients becoming refractory after their 2nd therapy, and 23 patients becoming refractory after their 3rd or later therapy; 27 patients had received stem cell transplant prior to becoming refractory. Outcomes were poor regardless of when patients became refractory (figure). Patients received a median (range) of 2 (0-8) treatments after becoming refractory with 40% (N=54) attempting subsequent platinum based salvage therapy and 14% (N=9) proceeding to ASCT, of which only 6 remain alive in long-term remission. 41 patients (30%) were treated on clinical trials after becoming refractory. Response rate for the first therapy after becoming refractory was 21%, while 29% of patients had a response to any subsequent therapy. Once patients became refractory, there was no difference in survival based on response at end of initial IC (p=0.33), cell of origin at diagnosis (p=0.64), IPI at diagnosis (p=0.33), or age when refractory (p=0.66). Outcomes in patients with transient response to IC (n=58) were poor, with the majority (N=37, 63%) becoming refractory to subsequent therapy. Median OS after first relapse was 6.7 months in patients with transient response to IC, which was equivalent to patients refractory to IC (p=0.99). The majority of patients with transient response to IC (69%) were next treated with platinum based salvage therapy which had a response rate of 40%. Ultimately 15 of the 58 patients (26%) proceeded to transplant, of which only 5 (9%) achieved long-term remission. Conclusions. Approximately 13% of patients with DLBCL become refractory to treatment in their disease course. Outcomes once patients become refractory are extremely poor regardless of when patients become refractory. Standard prognostic factors are no longer predictive of outcome and stem cell transplant had limited benefit in this group of patients. Patients with transient response to initial immunochemotherapy should be included when classifying patients as refractory. New therapy strategies are needed in the refractory setting. Figure 1. Figure 1. Disclosures Maurer: Kite Pharma: Research Funding. Thompson:Kite Pharma: Research Funding. Farooq:Kite Pharma: Research Funding. Cerhan:Kite Pharma: Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Link:Genentech: Consultancy, Research Funding; Kite Pharma: Research Funding.

Adoptive immunotherapy using T cells armed with chimeric antigen receptors (CAR) has proven extremely effective against CD19+ B-lineage acute lymphoblastic leukemia (ALL) with remission rates as high as 70-90% in recent clinical trials in relapsed/refractory patients. CD8 T cells are typically thought of as the primary antitumor effector cells in an adoptively transferred product due to their potent cytolytic capabilities, whereas CD4 T cells are thought to primarily provide "help" to enhance CD8 T cell activity via cytokine production. However, CARs are synthetic constructs that likely alter the functionality of T cells. Further, CAR T cells are endowed with 2 specificities, one through the CAR and one through the endogenous T cell receptor (TCR). To evaluate the biology of CAR T cells, we sought to evaluate the impact of CAR expression on the functionality of T cells and to study the impact of TCR on CAR T cell activity using both human CAR T cells in a xenograft model and murine CAR T cells in a syngeneic murine model. A human or murine second-generation anti-CD19 scfv/CD28/CD3ζ CAR was transduced into human or mouse CD8 (CAR8) and CD4 (CAR4) T cells, respectively, and tested against pre-B ALL cell lines in human murine xenografts or syngeneic models. Surprisingly, human CAR4 cells alone had equivalent ability to eradicate the Nalm6 ALL in vivo as CAR8 cells. Although CAR8 cells more rapidly cleared leukemia (2 vs 4 days), relapse eventually occurred. In contrast, CAR4 cells eradicated leukemia more slowly, but persisted longer and prevented relapse. In mice receiving CAR4+CAR8 cell products, only CAR4 cells were detectable at day 55. Next we utilized our syngeneic murine system to study CAR4 and CAR8 activity in an immunocompetent system using TCR transgenic T cells with known TCR specificity against the male histocompatibility antigen, HY. As expected, when stimulated through the TCR, CAR8 cells produced cytokines and degranulated, as manifested by CD107a expression, whereas CAR4 cells only demonstrated a cytokine production response. However, murine CAR4 cells activated through the CAR receptor develop "CD8-like" cytolytic features characterized by degranulation and were able to completely eradicate leukemia in vivo when administered without CAR8 cells, similar to the human CAR4 cells. We then evaluated the effect of TCR antigen in vivo on CAR T cell function by comparing activity in male (HY+) vs female (HY-) recipients. CAR4 cells were curative in both male and female recipients. However, CAR8 treatment has no anti-tumor activity in male recipients indicating that CAR8 cells are very susceptible to the negative effects of TCR signaling. TCR antigen availability in vivo greatly increased the number of infused CAR4 cells (P=0.003, male vs female recipients), while they significantly decreased the number of CAR8 cells (P=0.0023, male vs female recipients) after 1 week. Interestingly, we found that there was significant down-regulation of CAR expression on both CAR4 and CAR8 cells in male recipients (HY+). PD-1 and Tim3 were expressed at low levels on CAR4 cells and CAR8 cells in female recipients. However, there was significantly higher PD-1 (P=0.0079) and TIM3 (p=0.014) expression on CAR8 cells in male vs female recipients, whereas there was no difference in PD-1 or Tim3 on CAR4 cells recovered from male vs female recipients. These data indicate that CAR4 cells are more functional and become less exhausted than CAR8 cells in the presence of TCR antigen. Finally, we evaluated the long-term persistence of CAR4 and CAR8 cells in our syngeneic model in which there is no xenogeneic reactivity allowing for long-term monitoring. At day 60 and day 80, CAR4 cells were detectable in bone marrow and spleen, whereas CAR8 cells had completely disappeared. Despite the long-term persistence of CAR4 cells in recipients with or without TCR antigen, CAR4 cells are not completely immune to effects of TCR activation. In male recipients after 60 days, CAR4 cells also start to express high PD-1 levels and have decreased CAR T cell counts. These findings have important implications for CAR therapy, particularly in the allogeneic setting where the presence of TCR antigen may be more likely to be present in the recipient. In addition, these results suggest that CAR4 cells alone are cytolytic, equally potent to CAR8 cells at eradicating leukemia in vivo, and may be superior due to better persistence and reduced susceptibility to exhaustion. Disclosures No relevant conflicts of interest to declare.

Background: Adult T-cell acute lymphoblastic leukemia / lymphoma (T-ALL) is an rare and aggressive hematological malignancy with overall survival (OS) according to the UKALL XII/E2993 of 48% at 5 years (Marks et al, Blood 2009). Over the last decade, the incorporation of L-asparaginase, dose intensification (similar to pediatric protocols), availability of newer agents such as clofarabine (Dec 2004) and nelarabine (Oct 2005) have been shown to improve outcomes. We carried out this study to see if the above mentioned changes in treatment have translated to an OS benefit. Methods: After due IRB approval, adults diagnosed with T-ALL from 1990-2014 at Mayo Clinic were identified. All clinical and pathologic data was retrospectively reviewed Comparative analysis was performed based on year of diagnosis before and after 2005 (Group 1, diagnosis prior to 2005, and Group 2, diagnosis post 2005). Survival was estimated using the Kaplan-Meier Method and log-rank test. Chi-square test was used to compare variables. Results: A. Patient Characteristics: Between 1990 and 2014, a total of 92 consecutive patients (pts) with T-ALL were identified. Median age at diagnosis was 33 years (range; 18-88 years) with 72% males. Distribution of pts by year of diagnosis was as follows: Group 1(n= 47) (51%), and Group 2 (n=45) (49%). Median overall survival was 97.2 months. Median follow up for Group 1 was 50 months, during which time 23 (39%) deaths were documented, and 22.8 months (0.9 - 115.4) for Group 2 at which time19 deaths (42%) were documented (p= 0.04). Pts in Group 2 were older than Group1 (median age 41 vs 27 years (p= 0.004). Apart from age, the two groups were similar in other characteristics (Table 1). B. Therapy received by patient groups: We observed a high use of L-asparaginase containing regimens in Group 1 vs Group 2 [35(74%) pts vs 19 (42%), p=0.0013]. In contrast there was an increase in use of Hyper-CVAD in Group 2; 23(51%) vs. 3 (6%) (p C. Overall outcome by patient groups: We did not observe any difference in CR, or relapse rates among the two groups. The median OS and time to relapse were also not statistically different among Group 1 and 2 [102.6 vs 61.8 months Figure A, and 7.1 vs 14.1 months respectively]. Furthermore, age adjusted survival analysis was also not statistically significant. Conclusion: In this large cohort of adult T-ALL patients, in spite of significant advances in treatment strategies over the last two decades, we observed no difference in overall and relapse free survival prior to and after 2005. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding. Witzig:Spectrum: Research Funding; Novartis: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Valeant Pharma: Equity Ownership.

Background: Adult relapsed/refractory acute lymphoblastic leukemia/lymphoma (rALL) carries a very poor prognosis with limited options for effective salvage therapy. To date, there has been only a single retrospective report on the use of clofarabine in adult rALL demonstrating CR rate of 31% in this setting (Barba P et al. 2012). Aim: To evaluate the efficacy and toxicity of clofarabine based therapy in a relatively large cohort of adult rALL patients. Method: After IRB approval, a retrospective single institution study of all patients (pts) diagnosed with rALL treated with a clofarabine based regimen at Mayo Clinic between 2000 - 2014 was performed. Categorical variables were analyzed using Pearson's chi-squared test while continuous variables were analyzed using the Wilcoxon / Kruskal-Wallis test with P < 0.05 considered statistically significant. Survival estimates were calculated using Kaplan-Meier method and means were compared using log ranks. Results: Presenting features: We identified a total of 22 pts with a diagnosis of rALL who received clofarabine based therapy. 20 patients were evaluable and 2 were excluded (one received clofarabine as salvage for positive MRD and the other as systemic maintenance with CNS directed therapy for an isolated CNS relapse). Among evaluable pts, median age at time of Clofarabine based chemotherapy was 39 years (range 19-65) and 50% were males. Thirteen had B-ALL while 7 had T-ALL. Median leukocyte count was 6 x109 (0.2-28.7), hemoglobin 9.8 g/dL (7-12.9), platelet 65 x109 (12-493), peripheral blood blast 4% (0-88) and bone marrow blasts 80% (0-95) while five pts had extramedullary disease. Median number of prior regimens was 2 (1-7).. 8 (40%) pts were post allogeneic transplant Treatment and Response: 10 pts (50%) received clofarabine monotherapy, 7(35%) clofarabine and cytarabine, and 3 (15%) had clofarabine, etoposide and cyclophosphamide. Overall response rate (CR/CRi + PR) was 35%. Five (25%) achieved CR/CRi, and 2 achieved PR. Among those who achieved CR, 4 out 5 proceeded to further therapy; 2 to allogeneic stem cell transplant and two additional patients received donor lymphocyte infusion (DLI). One pt with PR also proceeded to allogeneic stem cell transplant. In comparative analysis, there were more males 6 (86%) vs 1(14%) in the responding arm (P = 0.014), otherwise the number of regimens prior to clofarabine, type of clofarabine regimen, transplant status, T vs B cell ALL, did not impact response. Median overall survival was 2.4 months (1.3-2.9) in non-responders vs. 12.8 months (3-27.4) in responders (P =0.0007) (Figure 1). All pts who proceeded to transplant or DLI relapsed with a median time to relapse of 6.4 (4.8-13.7) months. Toxicity: Rash/Hand Foot syndrome was observed in 3 pts (19%), Grade III-IV liver toxicity occurred in 4 (26%) with no permanent sequela. Opportunistic infection occurred in 3 pt (17%). Conclusion: Clofarabine based chemotherapy was a well-tolerated salvage regimen in heavily pretreated patients and was an effective bridge to definitive therapy in a significant proportion of cases. Prospective evaluation of these findings is warranted. Figure 1. Figure 1. Disclosures Al-Kali: Celgene: Research Funding.

Background: Acute T-cell lymphoblastic leukemia (T-ALL)/ lymphoma (T-LBL) are immature T-cell malignancies with very poor outcomes. In patients with relapsed disease, survival is often < 12 months (Marks et al, Blood, 2009). Prognostic correlates and treatment outcomes after relapse remain largely unknown. Aims: To evaluate prognostic correlates and treatment outcomes in patients with relapsed T-ALL/LBL. Methods: After IRB approval, 92 consecutive patients with T-cell ALL/LBL were identified. 41 patients with relapsed disease after achieving a first complete remission (CR1) were included in the study group. Features at the time of relapse were retrospectively abstracted and analyzed. Survival time after relapse was calculated from the time of relapse until death or last follow-up. Conventional methods were used for statistical analysis. Results: A. Baseline characteristics of all patients 92 patients were identified [41 LBL, 51 ALL]. Median age was 33 years (range; 18-88) and 66 (72%) were males. Median follow-up was 25 months (range 0.9-260). 13(14%) received palliative care or were lost to follow-up before treatment initiation. At last follow-up, there were 41 (52%, n = 79) relapses and 42 (46%, n = 92) deaths. Of 79 patients, 71 (90%) achieved a CR1 and 8 (10%) had primary refractory disease. Comparisons between ALL and LBL revealed expected differences in presenting features such as frequency of primary mediastinal mass at presentation in LBL and high leukocyte count in ALL. Significant differences in treatment were seen. Asparaginase-based and ALL-directed therapy were more common in the ALL group (71% vs. 45%, p = 0.009; 88% vs. 71%, p = 0.04). 13 (81%) LBL and 14 (27%) ALL underwent allogeneic SCT. The remaining three in each group underwent autologous SCT in CR1. B. Characteristics of relapsed patients 41 relapsed after achieving CR1 [23 LBL, 18 ALL]. Median time to relapse was 8.0 months (range 2.3-130), with no difference between ALL and LBL groups. Median age was 34 years (range 19-71) and 29 (71%) were males. Median follow-up after relapse was 7.2 months (range 0.3-207). At time of last follow-up, there were 30 (73%) deaths, 25 (61%) achieved a second complete remission (CR2) and 14 (34%) had persistent disease. 12 (48%) had relapse following CR2. 34 (83%) relapsed following CR1 after induction chemotherapy alone. 6 (15%) and 1 (2%) relapsed following allogeneic and autologous SCT respectively. 27 (66%) had BM involvement, 5 (12%) had CNS involvement, 13 (32%) had mediastinal involvement, and 3 (7%) had isolated extramedullary relapse. Ten (43%) patients with LBL relapsed with ALL. Of 27 patients with available data, 9 (33%) had high-risk cytogenetics at relapse, defined as ≥ 5 chromosomal abnormalities and/or markers known to confer an unfavorable prognosis. 16 of these 27 patients had follow-up cytogenetic studies performed, of which 8 (50%) had evidence of clonal evolution. Patients were treated with up to five regimens. 12 (31%) received asparaginase-based therapy and 13 (33%) received nelarabine with CR2 rates of 75% and 25% respectively. Median number of regimens needed to achieve CR2 was one. 18 (46%) went onto SCT following CR2: 14 (allogeneic), 3 (autologous), and 1 (donor lymphocyte infusion). The majority received myeloablative conditioning (92%). C. Outcomes and prognostic correlates for survival after relapse Median survival following relapse was 8.2 months (IQR 4.1-21.3) and did not differ between LBL and ALL. Nine (36%) who achieved CR2 are alive at time of last follow-up. 25 (61%) achieved CR2, but 12 (48%) relapsed following CR2, with median time to second relapse of 7.6 months (IQR 4.7-14). Nine of 18 who underwent SCT following CR2 had disease relapse (8 allogeneic, 1 autologous). Only BM involvement at relapse significantly correlated with post-relapse survival (HR 2.4 [1.1, 5.1], p = 0.03). Clonal evolution, high-risk cytogenetics, nelarabine therapy, achieving CR2, and SCT were not independent predictors of survival in our small subset of patients. Conclusion: Patients with relapsed T-ALL/LBL have dismal outcomes, in spite of advances in therapy with newer agents such as nelarabine and the use of allogeneic SCT. Regardless of T-ALL/LBL subtype, BM involvement at relapse appears to be a significant factor negatively impacting post-relapse survival. Further studies are needed to validate these findings. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding.