Abstract: Multiple myeloma (MM) is a neoplasm thought to arise from a damaged germinal center B-cell that progresses to a plasma cell clone arising in bone marrow. MM comprises 20% of all hematologic cancer deaths. Persons of African ancestry (AA) have a 1.5 to 2-fold higher risk compared to individuals of European ancestry (EA). Genetically driven differences in hematopoiesis may lead to variation in the levels white blood cell (WBC) subsets which could, in turn, be associated with MM etiology. There are differences in genetic determinants of WBC traits between EA and AA populations, with possible implications for the racial disparity in risk. We tested the above hypothesis using Mendelian randomization (MR), an approach that leverages genetic determinants of specific traits (i.e. WBC counts) to estimate their effects on the risk of an outcome; and a transcriptome-wide association study (TWAS), which utilizes genetic predictors of gene expression to identify susceptibility genes. These analytic approaches were applied to data from the African American Multiple Myeloma Study (AAMMS) consisting of 1813 cases and 8871 AA cancer-free controls to examine how differences in heritable WBC gene expression profiles influence MM risk. Genetic determinants of variation in WBC subsets in AA were obtained from the literature and supplemented with new genome-wide association findings in AA subjects from the UK Biobank cohort (n=6108). Odds ratios (OR) for MM per 1 standard deviation (SD) increase in each WBC phenotype were estimated using independent (linkage disequilibrium (LD) r2 〈 0.10) variants with P 〈 10-6 as genetic instruments. Analyses based on variants associated with WBC traits in AA populations did not identify any statistically-significant associations between MM risk and WBC overall (p=0.81, using 15 SNPs) or subsets (lymphocytes, monocytes, eosinophils, neutrophils and basophils, p 〉 0.05 for each). However, when we applied genetic determinants of WBC identified in 330,000 cancer-free EA UK Biobank participants (P 〈 10-8, replication P 〈 0.05, LD r2 〈 0.05), a statistically significant inverse relationship emerged between increasing lymphocyte counts and MM risk (OR=0.80, 95% CI: 0.66-0.97, p=0.02, using 385 SNPs), as well as increasing basophil counts (OR=0.63, 95% CI: 0.41-0.96, p=0.03, using 140 SNPs). Next, we examined the association between WBC gene expression profiles and MM risk in AAMMS data. We applied published and validated ancestry-specific models developed using the PrediXcan approach, which leverage germline genetic and transcriptomic data from the Multi-Ethnic Study of Atherosclerosis (MESA) (Mogil et al. PMID: 30096133). The primary TWAS used gene expression models trained in AA subjects (n=233), with sensitivity analyses using models developed in AA and Hispanic subjects (n=585). The TWAS significance threshold was based on the number of genes with significant germline prediction models (p 〈 0.05 and R2 ≥0.05) in AA, corresponding to P 〈 0.05/2700 = 1.85×10-5. The expression of two genes was significantly associated with MM risk: KANK1at 9p24.3 (P = 1.01×10-5) and DNAJC27at 2p23.3 (P = 1.56×10-5). KANK1is a candidate tumor suppressor gene for renal cell carcinoma and has recently been associated with MM risk in AA [Du, Blood 2017 130:3058]. Here we provide additional evidence for its role in MM etiology via gene expression-mediated mechanisms. DNAJC27 (previously known as RBJ) is a novel MM risk gene linked to constitutive activation of ERK in solid tumors. We also identified two suggestively associated genes: PRR14 (P = 1.34×10-4; combined AA-Hispanic sample: P = 1.56×10-6), which has been linked to MM risk in EA populations, and PARP16 (P = 9.46×10-5). To our knowledge this is the first study to comprehensively examine variation in WBC traits and gene expression profiles with respect to MM risk in AA. Our TWAS analysis leveraged data from the largest collection of genetic and gene expression data in AA, enabling ancestry-matched inference and identification of two novel risk genes. Although the limited availability of genetic instruments for WBC limited the power of MR analysis, findings using variants identified in European populations may offer some insight into trans-ethnic etiologic pathways and contribute to risk stratification strategies using genetic and blood cell count biomarkers. Future studies, particularly with MGUS-free controls, are needed to validate these results. Disclosures Song: Millennium Pharmaceuticals Inc: Employment. Rand:Ancestry.com: Employment. Ailawadhi:Cellectar: Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy; Pharmacyclics: Research Funding; Amgen: Consultancy, Research Funding; Takeda: Consultancy. Nooka:Takeda: Honoraria, Other: advisory board participation; Janssen: Honoraria, Other: advisory board participation; GSK: Honoraria, Other: advisory board participation; Spectrum pharmaceuticals: Honoraria, Other: advisory board participation; Adaptive technologies: Honoraria, Other: advisory board participation; Amgen: Honoraria, Other: advisory board participation; Celgene: Honoraria, Other: advisory board participation; BMS: Honoraria, Other: advisory board participation. Singhal:Bureau of Millennium/Takeda, Celgene, Janssen, Celgene, Bristol-Myers Squibb and Bluebird: Speakers Bureau. van Rhee:Takeda: Consultancy; Sanofi Genzyme: Consultancy; Castleman Disease Collaborative Network: Consultancy; EUSA: Consultancy; Adicet Bio: Consultancy; Kite Pharma: Consultancy; Karyopharm Therapeutics: Consultancy. Mehta:Millennium/Takeda, Celgene; stock in Celgene, Bristol-Myers Squibb and Bluebird: Speakers Bureau. Wolf:Takeda: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Janssen: Consultancy; Amgen: Consultancy. Martin:Roche and Juno: Consultancy; Amgen, Sanofi, Seattle Genetics: Research Funding. Fiala:Incyte: Research Funding. Terebelo:Jannsen: Speakers Bureau; Celgene: Honoraria; Newland Medical Asociates: Employment. Anderson:Bristol-Myers Squibb: Other: Scientific Founder; Oncopep: Other: Scientific Founder; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Sanofi-Aventis: Other: Advisory Board. Vij:Bristol-Myers Squibb: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Genentech: Honoraria; Janssen: Honoraria; Karyopharm: Honoraria; Sanofi: Honoraria; Takeda: Honoraria, Research Funding. Bernal-Mizrachi:TAKEDA: Research Funding; Kodikas Therapeutic Solutions, Inc: Equity Ownership; Winship Cancer Institute: Employment, Patents & Royalties. Morgan:Amgen, Roche, Abbvie, Takeda, Celgene, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Other: research grant, Research Funding. Zonder:Celgene Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Intellia: Consultancy, Membership on an entity's Board of Directors or advisory committees; Caelum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Alnylam: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees. Huff:Member of Safety Monitoring Board for Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees; Karyopharm, Sanofi, MiDiagnostics: Consultancy. Lonial:Karyopharm: Consultancy; Takeda: Consultancy, Research Funding; Amgen: Consultancy; BMS: Consultancy; Janssen: Consultancy, Research Funding; GSK: Consultancy; Celgene Corporation: Consultancy, Research Funding; Genentech: Consultancy. Orlowski:Poseida Therapeutics, Inc.: Research Funding.

Abstract: Background: Though CD19 is expressed only rarely on multiple myeloma (MM) plasma cells (PC), rare CD19+ B cells can be identified in MM patients that are clonally related to the MM PC. These clonotypic B cells may exhibit properties of cancer stem cells (enhanced MM-propagating properties and drug resistance compared to MM PC) and thus be a potential therapeutic target in conjunction with therapies that target MM PC. CTL019 consists of autologous T cells transduced via lentiviral vector with an anti-CD19 scFv coupled to CD3-zeta and 4-1BB signaling domains and expanded ex vivo with anti-CD3/CD28-conjugated beads. To target both clonotypic B cells and MM PC, we conducted a pilot clinical trial of CTL019 administered after high-dose melphalan and autologous stem cell transplantation (ASCT) in relapsed/refractory MM patients who had previously undergone first-line ASCT with short progression-free survival (PFS). Methods: Subjects were required to be medically fit for ASCT and have progressed within 1 year of a prior ASCT performed as part of first-line therapy. Study therapy consisted of ASCT with melphalan 140-200 mg/m2 followed by 1-5x107 CTL019 cells 12-14 days later. The primary endpoint was safety and feasibility of CTL019 manufacturing and administration in this clinical setting. Secondary endpoints included assessments of CTL019 in vivo persistence and activity against normal B cells, plasma cell immunophenotype as a response biomarker, and PFS after ASCT + CTL019 in comparison to PFS after initial ASCT. Results: Twelve subjects enrolled, and 10 received study therapy; autologous T cells failed to expand ex vivo in one enrolled subject, and one enrolled subject elected to pursue off-study therapy. Median age was 61 (range 48-68). Median prior lines of therapy was 6 (range 2-10). Poor-prognosis features were present in 8/10 subjects (6/10 with poor-prognosis cytogenetics, 2/10 with BRAF V600E mutations, 1/10 with secondary plasma cell leukemia). Median PFS after first-line ASCT was 258 days (range 100-342). In pre-ASCT bone marrow (BM), the dominant MM PC population was CD19-negative by flow cytometry in 9/9 evaluable subjects, though 7/9 exhibited rare CD19+ subsets comprising 0.05-1.5% of MM PC. Melphalan dose was 140 (N=7) or 200 (N=3) mg/m2. All subjects infused received the maximum target dose of 5x107 CTL019 cells. Adverse events (AE) consisted mostly of expected ASCT toxicities. Grade ³3 AE that were at least possibly related to CTL019 included grade 3 autologous GVHD (N=1, resolved with corticosteroids) and oral mucositis (N=1). Grade 1 cytokine release syndrome occurred in 1 subject. There was no ASCT-related mortality. After infusion, CTL019 cells were detectable in peripheral blood (PB) of all subjects and persisted for median of 44 days (range 14-156). Presence of PB CTL019 cells was associated with absence of PB B cells. Notably, CTL019 cells were detected in BM in 9/10 subjects at day 42 and/or 100 post-ASCT. Median PFS after ASCT + CTL019 was 185 days (range 42-479); all subjects have progressed. The peak BM CTL019 frequency correlated significantly with favorable PFS (SpearmanÕs rho=0.77, P=0.009). There was no association between PFS and peak frequency of CTL019 or duration of CTL019 persistence in PB. In 3/10 subjects, PFS after ASCT + CTL019 met or exceeded PFS after first-line ASCT (Figure). For comparison, in a historical cohort of 18 patients who received first-line and salvage ASCT at our institution since 2008, no patients exhibited longer PFS after salvage ASCT. Conclusion: CTL019 manufacturing and administration post-ASCT is safe and feasible in patients with advanced MM. Correlation of PFS with CTL019 frequency in BM and prolonged PFS in 3 subjects is suggestive of clinical efficacy. A phase-two study of CTL019 using a 10-fold higher dose after first-line ASCT in high-risk MM patients is ongoing. Figure. Figure. Disclosures Garfall: Medimmune: Consultancy; Bioinvent: Research Funding; Novartis: Consultancy, Research Funding. Stadtmauer:Novartis: Consultancy; Takada: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Teva: Consultancy; Celgene: Consultancy. Maus:Novartis: Patents & Royalties: related to CTL019, Research Funding. Hwang:Novartis: Research Funding. Vogl:Takeda: Consultancy, Research Funding; GSK: Research Funding; Calithera: Research Funding; Teva: Consultancy; Constellation: Research Funding; Celgene: Consultancy; Acetylon: Research Funding; Karyopharm: Consultancy. Cohen:Bristol-Meyers Squibb: Consultancy, Research Funding; Janssen: Consultancy. Weiss:Novartis: Consultancy. Porter:Genentech: Employment; Novartis: Patents & Royalties, Research Funding. Frey:Novartis: Research Funding; Amgen: Consultancy. Milone:Novartis: Patents & Royalties, Research Funding. Mangan:Novartis: Speakers Bureau. Lacey:Novartis: Research Funding. Melenhorst:Novartis: Patents & Royalties: Novartis, Research Funding. Ambrose:Novartis: Research Funding. Chen:Novartis: Research Funding. Kulikovskaya:Novartis: Research Funding. Levine:Novartis: Patents & Royalties, Research Funding; GE Healthcare Bio-Sciences: Consultancy. June:Johnson & Johnson: Honoraria; Tmunity Therapeutics: Equity Ownership; Novartis: Honoraria, Patents & Royalties, Research Funding; Immune Design: Consultancy, Equity Ownership; Celldex: Consultancy, Equity Ownership; Novartis: Honoraria, Patents & Royalties, Research Funding; Pfizer: Honoraria.

Abstract: Background: Persons of African ancestry (AA) have a 2-3-fold higher risk of multiple myeloma (MM) than persons of European ancestry (EA). Like other B-cell malignancies, genome-wide association scans (GWAS) have identified MM risk variants in the HLA region in persons of EA. We conducted a case-control analysis with data from the National Marrow Donor Program (NMDP)1comprising MM patients typed for bone marrow transplant to donor controls matched by race-ethnicity, and found associations between specific HLA alleles/haplotypes and MM risk that varied by race and ethnicity. To confirm our results and identify additional novel signals, we have now investigated associations between HLA alleles and haplotypes and MM risk in the African American Multiple Myeloma Study (AAMMS) Cohort. Methods: The source of subjects was the AAMMS, in which AA MM patients were identified from 10 cancer centers and 4 Surveillance, Epidemiology and End-Results (SEER) Program cancer registries in order to identify genetic risk factors for MM among AAs. A GWAS was conducted using the Illumina Human Core BeadChip array on DNA samples from 1,305 AA MM patients in the AAMMS comparing results to those from 7,078 AA controls with GWAS data generated from the Illumina 1MDuo2. The major histocompatibility complex (MHC) region single nucleotide polymorphisms (SNPs) were imputed to classical HLA variants using HIBAG. Unconditional logistic regression was used to estimate HLA associations, adjusting for sex, age and the first 2 principal components. P-values were adjusted for false discovery rate (FDR) for each locus group. Results: We did not identify any single HLA alleles associated with MM risk among AAs. However, several B*07:02-containing haplotypes were associated with MM risk (odds ratios [OR] ranging from 2.38 to 2.64 and FDR P-values ranging from 1.43 x 10-6 to 3.57 x 10-8). We found associations between MM risk and genotypes containing DRB3*02:02, including DRB3*02:02~DRB1*11:01+ DRB3*02:02~DRB1*11:01 (OR=1.93, PFDR= 9.36 x 10-5) similar to those observed in the NMDP study1. Novel findings included associations between MM risk and HLA Class I haplotypes B*53:01+ B*57:01 (OR=1.94, PFDR= 0.003) and C04:01~B*53:01+C*06:02~B*57:01 (OR=1.96, PFDR= 0.0050). Results from an ongoing meta-analysis between the two data sets (one based on an imputed GWAS and one based on NMDP HLA typing) will be presented. Conclusions: This study is the second to examine HLA alleles and risk of MM among AA's and is by far the largest. We confirmed a previously observed association between an HLA Class II DRB3 variant and MM risk and confirmed an association with B*07 haplotypes previously observed among EAs1. We also identified novel associations between other HLA Class I haplotypes and MM risk in AA's. Because HLA is highly polymorphic, many HLA alleles are rare variants for which genetic associations are difficult to detect without very large sample sizes. Further investigation with large sample sizes will be necessary to refine these associations in order to better identify the underlying causal alleles and determine the functional significance of these HLA associations. 1Beksac M, Gragert L, Fingerson S, et al.: HLA polymorphism and risk of multiple myeloma.Leukemia. 2016 Jul 27. doi: 10.1038/leu.2016.199. 2Rand KA, Song C, Hwang AE, et al. Genetic susceptibility markers of multiple myeloma in African-Americans. Abstract # 2030, 56th Annual American Society of Hematology Meeting, San Francisco, California, 2014. Disclosures Ailawadhi: Pharmacyclics: Consultancy; Novartis: Consultancy; Amgen Inc: Consultancy; Takeda Oncology: Consultancy. Nooka:Spectrum, Novartis, Onyx pharmaceuticals: Consultancy. Zonder:Pharmacyclics: Other: DSMC membership; Prothena: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Lonial:BMS: Consultancy; Novartis: Consultancy; Millenium: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Merck: Consultancy; Celgene: Consultancy; BMS: Consultancy; Novartis: Consultancy; Onyx: Consultancy; Janssen: Consultancy; Onyx: Consultancy.

Abstract: The adoptive transfer of autologous T cells genetically modified to express a CD19-specific, 4-1BB/CD3z-signaling CAR (CTL019) has shown remarkable activity and induce long-term remissions in a subset of patients with relapsed/refractory chronic lymphocytic leukemia (CLL). To date, little is known about predictive indicators of efficacy. This study was designed to evaluate biomarkers of clinical response to CTL019 in CLL. We studied forty-one patients with advanced, heavily pre-treated and high-risk CLL who received at least one dose of CTL019 cells. We show that in vivo expansion and persistence are key quality attributes of CTL019 cells in CLL patients who have complete responses to therapy; in 2 patients responses are sustained beyond five years and accompanied by the persistence of functional CTL019 cells. Furthermore, durable remissions were associated with transcriptomic signatures of early memory T cells, while T cells from non-responding patients were enriched in genes belonging to known pathways of terminal differentiation and exhaustion. Polychromatic flow cytometry also demonstrated a significantly higher level of T cell exhaustion markers on the infused CAR T cells and reduced CD27 expression in non-responding patients. Accordingly, the combined assessment of PD1 and CD27 expression on CD8+ CTL019 cells in the infusion product accurately predicted response to treatment. Restimulation of the infusion product through the CAR further demonstrated that CTL019 cells from complete responders secreted significantly higher levels of several cytokines, including CCL20, IL-21, IL-22, IL-17, and IL-6, suggesting that the STAT3 signaling pathway may play a role in potentiating the enhanced potency of CTL019 cells. To identify a phenotype of T cells that is predictive of response prior to CTL019 manufacturing, we initially retrospectively evaluated the proportions of naïve, stem cell memory, central memory, effector memory and effector cells at the time of leukapheresis and observed either marginally significant or no significant correlations with clinical outcome. A systematic, unbiased analysis of the same biomarker panel revealed that the frequency of CD27+CD45RO- cells in the CD8+ T cell population correlated significantly with complete and durable responses to this therapy. Analysis of the infusion products using the same flow cytometric panel showed that most ( 〉 95%) of T cells expressed CD45RO at the end of the manufacturing run; CD27 expression frequencies, however, were maintained at the same level as in the leukapheresis. Together, these findings suggest that intrinsic T cell fitness dictates both response and resistance to highly active engineered CAR T cells. Thus, enrichment of T cells with optimal differentiation potential and proliferative capacity by timing of collection or culture modification might potentiate the generation of maximally efficacious infusion products. These data and additional immunological biomarkers may be used to identify which patients are most likely to respond to adoptive transfer strategies, leading to an enhanced personalized approach to cellular therapy. Disclosures Fraietta: Novartis: Patents & Royalties: Novartis, Research Funding. Lacey:Novartis: Research Funding. Wilcox:Novartis: Research Funding. Bedoya:Novartis: Research Funding. Chen:Novartis: Research Funding. Orlando:Novartis: Employment. Brogdon:Novartis: Employment. Hwang:Novartis: Research Funding. Frey:Novartis: Research Funding; Amgen: Consultancy. Pequignot:Novartis: Research Funding. Ambrose:Novartis: Research Funding. Levine:Novartis: Patents & Royalties, Research Funding; GE Healthcare Bio-Sciences: Consultancy. Bitter:Novartis: Employment. Porter:Genentech: Employment; Novartis: Patents & Royalties, Research Funding. Xu:Novartis: Research Funding. June:Immune Design: Consultancy, Equity Ownership; University of Pennsylvania: Patents & Royalties; Celldex: Consultancy, Equity Ownership; Novartis: Honoraria, Patents & Royalties: Immunology, Research Funding; Tmunity: Equity Ownership, Other: Founder, stockholder ; Pfizer: Honoraria; Johnson & Johnson: Research Funding. Melenhorst:Novartis: Patents & Royalties: Novartis, Research Funding.

Abstract: Hodgkin lymphoma (HL) is derived from germinal center B-lymphocytes, has a peak incidence in adolescents and young adults (AYA) in developed countries and results in substantial treatment-related late effects. We previously identified a SNP (rs1860661G) in the TCF3 gene, inversely associated with HL risk, that is also mutated in tumor cells. The protein encoded by TCF3 is responsible for maintaining the B-cell program, which is downregulated in HRS cells; therefore higher expression levels may be protective.1 DNA methylation is associated with repression of gene expression and may thereby play a role in HL pathogenesis. We extracted DNA from blood samples obtained from HL survivors and their unaffected monozygotic MZ twins (4 female and 5 male twin pairs discordant for AYA HL). Average age at blood draw was 62 years, and average time since diagnosis of the case was 34 years. We also extracted DNA from blood samples from 25 unaffected MZ twin pairs as control pairs. DNAs were bisulfite converted and DNA methylation quantified using the Illumina Infinium HumanMethylation27 BeadChip array, which scores methylation levels as β values. We compared average DNA methylation β value differences at the TCF3 locus cg16524139 (near rs1860661) in HL survivors and their unaffected co-twins using a paired t-test. We also examined the TCF3 germline genotype by DNA methylation level rank in HL-discordant pairs. We also computed DNA methylation age, a global measure of physiological aging, using a validated algorithm2 and compared the result in the HL survivor to that of each corresponding unaffected co-twin using a paired t-test. We found a small but significantly higher DNA methylation level at the TCF3 locus in HL survivors compared to their unaffected co-twins (p=0.05), but no difference between the members of healthy MZ twin pairs (p=0.81). The protective allele (G) was more prevalent in the 6 pairs with higher DNA methylation level in HL survivors (33%), compared to the 3 pairs with higher levels in unaffected co-twins (17%). This pattern would be expected if methylation at the cg16524139 were to diminish TCF3 expression related to a protective rs1860661G variant. HL survivors had an average DNA methylation age of 64.1 years compared to 61.3 years in their unaffected MZ co-twins (p=0.04). Differential DNA methylation in HL survivors and their unaffected twins suggests a role for DNA methylation in HL, possibly as a result of treatment or disease. 1. Cozen W, Timofeeva MN, Li D, Diepstra A, Hazelett D, Delahaye-Sourdeix M, et al.: A meta-analysis of Hodgkin lymphoma reveals 19p13.3 TCF3 as a novel susceptibility locus. Nat Comm 25:3856. doi: 10.1038/ ncomms 4856, 2014 2. Horvath S: DNA methylation age of human tissues and cell types. Genome Biol, 14:R115 doi:10.1186/gb-2013-14-10-r115, 2013. Disclosures No relevant conflicts of interest to declare.

Abstract: CD19-targeted T-cell immunotherapy reveals that a population of PCs lacking CD19 expression survives long-term, independent of B cells. Preexisting humoral immunity to vaccine-related antigens can persist in patients despite marked B-cell aplasia after CTL019 immunotherapy.

Abstract: Background: Delayed or failed engraftment after adult UCBT is a major contributor to the morbidity, mortality and resource utilization associated with this procedure. Increasing the number of hematopoietic stem and progenitor cells within the cord blood graft may overcome this limitation. NiCord, developed and manufactured by Gamida Cell, is an ex vivo-expanded, cryopreserved graft derived from an entire cord blood unit (CBU). In a pilot study, NiCord transplanted with a second, unmanipulated CBU was shown to shorten time to neutrophil engraftment and provide long-term hematopoiesis (Horwitz M, JCI 2014). In another study, NiCord UCBT demonstrated clinical benefit by reducing the incidence of severe infections as well as the duration of hospitalization during the first 100 days following transplantation (Anand S BBMT 2017). With confirmation that NiCord expands both hematopoietic stem and progenitor cells, we conducted a multicenter study using NiCord as a single stem cell graft. Methods: The study objective was to assess safety and efficacy of NiCord as a single, ex vivo expanded stem cell graft. The primary endpoint was to assess the cumulative incidence of NiCord-derived neutrophil engraftment. Thirty-five evaluable patients, median age 44 (13-63) with ALL (n=9), AML (n=16), MDS (n=7), CML (n=2) or Hodgkin lymphoma (n=1) were transplanted at 10 sites in the USA, EU, and Singapore. 79% had intermediate-high risk disease by Disease Risk Index. All patients received myeloablative conditioning with a TBI-based (n=14) or chemotherapy-only (n=21) regimen. Graft vs. host disease (GvHD) prophylaxis consisted of MMF for a minimum of 60 days and tacrolimus or cyclosporine for a minimum of 180 days. HLA matching was 4/6 (n=25), 5/6 (n=8) or 6/6 (n=2). Results: NiCord processing resulted in a median 32-fold (20-52 fold) increase in CD34+ cells relative to that reported by the cord blood bank prior to cryopreservation. This translated to a median CD34+ cell dose of 6.3 x 106/kg (1.4-14.9 x 106/kg). The cumulative incidence of engraftment at day 42 was 94%. Two patients experienced secondary graft failure; one at day 40 due to HHV6 infection, and another at day 260 due to an overwhelming, lethal adenovirus infection. Neutrophil engraftment occurred at a median of 11 days (95% CI: 9-13 days)(Figure 1). Platelet engraftment occurred at a median 34 days (95% CI:32-42 days)(Figure 2). Full donor whole blood chimerism (≥ 95%) was observed in 100% of engrafted patients by day 100 following transplantation. The incidence of grade II-IV and grade III/IV acute GvHD was 48.6% and 12.2%, respectively. Cumulative incidence of all chronic GvHD was 45%, and moderate/severe cGvHD 11.5% at 1 year following transplantation. Median CD3+, CD4+, and CD19+ lymphocyte counts were 286/µl, 183/µl, and 147/µl at day 100, and 479/µl, 290/µl, and 446/µl at 6 months, respectively. The incidence of grade 2-3 bacterial (n=9) or grade 3 fungal (n=0) infections was 23.9% by day 100. With a median follow-up of 13 months (range 1-35 months), the 6-month and 2-year non-relapse mortality was 12.8% and 20.3%, respectively. The cumulative incidence of relapse was 27% at 2 years. The Kaplan-Meier estimate of overall survival at 6 months and 2 years was 80.5% and 50.8%, respectively. Conclusions: The rapid engraftment kinetic coupled with a low graft failure rate and durable hematopoiesis suggests a favorable safety profile of NiCord as a single umbilical cord blood graft. Ex vivo expansion of the CBU resulted in a CD34+ cell dose comparable to adult mobilized peripheral blood stem cell grafts. Compared to a recently reported multi-center phase II study of adult, unmanipulated myeloablative double UCBT (Barker J, Br. J. Haem 2014), NiCord markedly reduced the median time to neutrophil recovery (11 days vs. 22 days) and platelet recovery (34 days vs. 49 days). Transplantation of NiCord appears not to adversely affect cellular immune recovery. Quantitative assessment of neutrophil, T-cell, and B-cell recovery is comparable to that observed following adult matched unrelated donor transplantation. We conclude that UCBT using NiCord has the potential to broaden accessibility to stem cell transplantation and to become a graft of choice for patients without a matched donor. A global randomized phase III study of NiCord vs. standard UCBT is ongoing (NCT02730299). Figure 1 Figure 1. Disclosures Jagasia: Therakos: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Mallinckrodt: Consultancy. Wagner: Magenta Therapeutics: Research Funding; Novartis: Research Funding. Kuball: Gadeta (www.gadeta.nl): Consultancy, Equity Ownership, Patents & Royalties: on gdT cells and receptors and isolation strategies , Research Funding; Miltenyi: Research Funding. Majhail: Anthem, Inc.: Consultancy; Sanofi: Honoraria. Montesinos: Celgene Corporation: Honoraria, Research Funding. Kurtzberg: Gamida Cell: Research Funding. Sanz: Gamida Cell: Research Funding.

Abstract: Introduction CD19 directed CAR T cells have shown potent activity in relapsed/refractory (R/R) aggressive B-cell lymphomas (B-NHL) leading to the FDA approval of axicabtagene ciloleucel (axi-cel, Oct 2017) and tisagenlecleucel (tisa-cel, May 2018). Initial reports on commercial application of axi-cel suggest many patients (pts) would not have met eligibility criteria for the ZUMA-1 clinical trial, yet outcomes and toxicities appeared similar (Nastoupil LJ, et al. Blood 2018 132:91 and Jacobson CA, et al. Blood 2018 132:92). No data on the "real world" application of tisa-cel is available. We performed a multicenter retrospective study to include both approved commercial products, axi-cel and tisa-cel, given in centers that had the option of prescribing either product. We evaluate patterns of use, efficacy, and safety. Methods We retrospectively analyzed data from pts who underwent apheresis for commercial axi-cel or tisa-cel from 8 US academic centers. Data collection started after 5/1/2018, following FDA approval of tisa-cel when centers would have a choice to prescribe either axi-cel or tisa-cel for B-NHL. Centers were invited to participate if they were certified to administer both products. Patient and treatment characteristics were summarized descriptively. Response and toxicity were reported with 95% exact binomial CIs. Results As of 7/31/2019, 242 pts underwent apheresis for commercial CAR T-cell products. Of these, 163 (67%) underwent apheresis for axi-cel, and 79 (33%) for tisa-cel. 14 (9%) axi-cel and 3 (4%) tisa-cel pts died prior to CAR T-cell infusion from lymphoma progression, and 1 (1%) tisa-cel pt was not infused for other reasons. Detailed baseline pt characteristics were available for 180/242 pts (Table 1). Median age at apheresis was 58 years (range: 18-85) for axi-cel pts and 67 years (range: 36-88) for tisa-cel pts. ECOG PS was 0-1 in 86% of axi-cel and 94% of tisa-cel pts. By histology, 77% of axi-cel pts had DLBCL, 13% TFL, 9% HGBL and 2% PMBCL. Similarly, 81% of tisa-cel pts had DLBCL, 13% HGBL, and 6% TFL. The median number of prior therapies was 3 (range: 2-11) for axi-cel and 4 (range: 2-9) for tisa-cel pts. Prior autologous stem cell transplant was performed in 29% of axi-cel and 23% of tisa-cel pts, respectively. Bridging therapy was given in 61% of axi-cel and 72% of tisa-cel pts. Median time from apheresis to CAR T-cell infusion was 28 days for axi-cel and 44 days for tisa-cel. CAR T-cell infusion was inpatient in 100% of axi-cel and 39% of tisa-cel pts. Safety was evaluable in 213 pts. CRS was graded according to institutional practices (CARTOX (38%), Penn scale (31%), ASTCT (19%), and Lee scale (11%)). NEs were graded per CARTOX (80%), ASTCT (19%), or CTCAE V4.03 (1%). Grade ≥3 CRS and NEs occurred in 13% and 41% of axi-cel pts and 1% and 3% of tisa-cel pts. The median onset of CRS and NEs was 2 and 6 days in axi-cel, and 3 and 5 days in tisa-cel treated pts, respectively. Tocilizumab was administered in 62% of axi-cel pts with 57% receiving steroids. In tisa-cel pts, tocilizumab was administered in 13% of cases, with 7% receiving steroids. 12 deaths (8%) unrelated to lymphoma progression occurred in axi-cel pts at a median of 57 days (range: 6-373) with 5 due to infectious complications, 4 due to grade 5 NEs, 1 due to cardiac disease, 1 due to pulmonary hemorrhage, and 1 due to HLH. 4 deaths (6%) unrelated to lymphoma progression occurred in tisa-cel pts at a median of 48 days (range: 25-146) with 2 due to infectious complications, 1 due to cardiac disease, and 1 due to unknown causes. Response assessment was performed for infused pts at day 30 and/or day 90, or in those determined to have clinical progression. Of 120 axi-cel pts evaluable at day 30, the ORR was 72% with 43% achieving a CR. Of the 32 tisa-cel pts evaluable at day 30, the ORR was 59% with 44% achieving a CR. At day 90, the ORR for axi-cel was 52% with 39% achieving a CR, while for tisa-cel the ORR was 48% with 39% achieving a CR. Conclusions Efficacy outcomes in the commercial setting appear similar to responses seen in the pivotal clinical trials. Though different toxicity grading scales were employed, tisa-cel appears to be associated with less CRS and NEs. Data from a larger group of pts treated at additional centers are being gathered. Analyses of usage patterns and updated outcomes with uniform ASTCT toxicity grading will be presented in an effort to better understand therapeutic decision making. Disclosures Riedell: Novartis: Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Bayer: Honoraria, Speakers Bureau. Nastoupil:Spectrum: Honoraria; TG Therapeutics: Honoraria, Research Funding; Novartis: Honoraria; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Genentech, Inc.: Honoraria, Research Funding; Bayer: Honoraria; Celgene: Honoraria, Research Funding. Maziarz:Kite: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding; Incyte: Consultancy, Honoraria; Celgene/Juno: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. McGuirk:Gamida Cell: Research Funding; Pluristem Ltd: Research Funding; Novartis: Research Funding; Fresenius Biotech: Research Funding; Astellas: Research Funding; Bellicum Pharmaceuticals: Research Funding; Kite Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Juno Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ArticulateScience LLC: Other: Assistance with manuscript preparation. Oluwole:Pfizer: Consultancy; Spectrum: Consultancy; Gilead Sciences: Consultancy; Bayer: Consultancy. Bachanova:Novartis: Research Funding; Celgene: Research Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Gamida Cell: Research Funding; GT Biopharma: Research Funding. Hwang:Tmunity: Research Funding; Novartis: Research Funding. Schuster:Pharmacyclics: Honoraria, Research Funding; Acerta: Honoraria, Research Funding; AstraZeneca: Honoraria; Loxo Oncology: Honoraria; Nordic Nanovector: Honoraria; Pfizer: Honoraria; Novartis: Honoraria, Patents & Royalties: Combination Therapies of CAR and PD-1 Inhibitors with royalties paid to Novartis, Research Funding; Celgene: Honoraria, Research Funding; Genentech: Honoraria, Research Funding; Merck: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Gilead: Honoraria, Research Funding. Perales:Bellicum: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; NexImmune: Membership on an entity's Board of Directors or advisory committees; MolMed: Membership on an entity's Board of Directors or advisory committees; Omeros: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Nektar Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Honoraria; Medigene: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Kyte/Gilead: Research Funding; Miltenyi: Research Funding. Bishop:Juno: Consultancy, Membership on an entity's Board of Directors or advisory committees; CRISPR Therapeutics: 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, Research Funding; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Porter:American Board of Internal Medicine: Membership on an entity's Board of Directors or advisory committees; Immunovative: Membership on an entity's Board of Directors or advisory committees; Genentech: Employment; Wiley and Sons: Honoraria; Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Glenmark Pharm: Membership on an entity's Board of Directors or advisory committees.

Abstract: Background Immunotherapy with anti-CD19 CART cells (CART19) induces complete remission (CR) in the minority of patients with CLL; however, these CRs tend to be durable (Porter Sci Tr Med 2015). Based on preclinical evidence of synergy, we combined anti-CD19 CAR T cells with ibrutinib to test the hypothesis that pre- and concurrent treatment enhances the CR rate. Methods This is a pilot trial of autologous anti-CD19 CAR T cells in adults with CLL/SLL who were not in CR despite at least 6 months of ibrutinib. T cells were lentivirally transduced to express a CAR comprising CD3z, 4-1BB, and humanized anti-CD19 scFv (CTL119). Pts underwent lymphodepleting chemotherapy up to 1 week before infusion, followed by planned infusion of 1-5x108 CTL119 cells dosed as 10%, 30% and 60% of the total planned dose over 3 days, with doses beyond dose#1 given only in the absence of fever or cytokine release syndrome (CRS). Results CTL119 manufacturing was successful for all pts. Twenty pts were enrolled and 19 were infused (one pt was not infused due to intercurrent large cell transformation and newly diagnosed adenocarcinoma). Of the 19, 15 were male, the median age was 62 (range 42-76); and 5 were on 1st line ibrutinib. Of the remaining 14, the median number of prior therapies was 2 (range 1-16), and 3 pts had received prior murine CART19 therapy (CTL019) without ibrutinib. Eleven pts had abnormalities of chromosome 17p or TP53. An additional 3 pts had abnormalities of chromosome 11q22 or ATM. All pts had marrow involvement (median 21% range 7-63%). For 9 pts who had enlarged nodes at baseline, the median cross-sectional area was 1471 mm2 (range 178-2220). All pts received at least 2 CTL119 doses; 14 patients received all 3 and 5 received 2 doses. The median number of CART cells given was 5.3x106/kg (range 2.0-7.5). Median peak CART cell number by qPCR was 90,990 copies/ug genomic DNA (range 965-210,556) and by flow cytometry was median 536 CART cell/ul blood (range, 0-3640). 18/19 (95%) pts experienced CRS, with a median Penn CRS Grade of 2. CRS was grade 1-2 and 3-4 in 15 and 3 pts, respectively. Two pts received tocilizumab. Of 5 pts with encephalopathy, 2 were CTCAE gr 1, 2 gr 2 and 1 gr 4. One pt died on D14 from a cardiac arrhythmia during severe neurotoxicity after resolution of CRS. There were 49 gr 3 and 22 gr 4 toxicities in total. As of 7/16/18, 18/19 pts are alive (95%) and 12 pts have been followed for at least 12 months. The median follow-up for the 18 surviving pts is 18.5 months (range 8-28). Per iwCLL criteria, at 3 months 14 pts were evaluable and their responses were CR (n=6), PR (n=4), SD (n=3), PD (n=1). Marrow responses at month 3 were available in 18 and showed a morphologic CR in 17 pts (94%); of these 15 also had no measurable residual disease (MRD) by 9-color flow cytometry. MRD was also assessed at 3 months by deep sequencing of the immunoglobulin heavy chain locus (limit of detection 1 B cell in 1x106 nucleated cells). 14/18 pts were MRD negative, and the remaining 4 had 3.36, 4.76, 1.79, and 0.48 log10 reduction of the leukemic clonotype relative to the baseline sample. LN biopsies from 2 pts 3 and 10 months after CTL119 confirmed absence of the CLL clonotypes in this compartment as well. At 12 months, 11 pts had evaluable marrows of which 10 (91%) were in morphologic CR and 1 showed morphologic relapse. Of the 10 in morphologic CR, three pts showed low MRD positivity (3.58, 2.34, 3.79 log10 reduction) and the rest remained MRD-ve. Of the 3 pts who had received murine CTL019 previously, 2 were in MRD+ve CR at 12 months and one was refractory to humanized CTL119. Six pts discontinued ibrutinib at a median 8 months (range 3-12) due to toxicity (n=2) or pt choice (n=4). Five pts remain MRD-ve at short followup. In total, 16/18 pts remain in morphologic and/or flow CR at last followup. Conclusion In patients not achieving CR despite at least 6 months of ibrutinib who were treated with humanized CART19, we found an iwCLL CR rate of 43% and a bone marrow remission rate of 94% including a 78% MRD negative response by deep sequencing. This compares favorably to prior CART19 cell studies in patients with progressive CLL (iwCLL CR rates of 21-29%). CRS was frequent but mild-moderate and did not commonly require anti-cytokine therapy. These results suggest that the combination of CTL119 with ibrutinib results in a high rate of sustained responses and high rates of MRD-ve marrow response in patients with CLL. This combination will be further tested in larger studies. Figure. Figure. Disclosures Gill: Carisma Therapeutics: Equity Ownership; Extellia: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding. Frey:Servier Consultancy: Consultancy; Novartis: Consultancy. Mato:Johnson & Johnson: Consultancy; Portola: Research Funding; Acerta: Research Funding; AstraZeneca: Consultancy; AbbVie: Consultancy, Research Funding; Pharmacyclics, an AbbVie Company: Consultancy, Research Funding; Regeneron: Research Funding; TG Therapeutics: Consultancy, Research Funding; Celgene: Consultancy; Medscape: Honoraria; Prime Oncology: Honoraria. Lacey:Novartis Pharmaceuticals Corporation: Patents & Royalties; Tmunity: Research Funding; Parker Foundation: Research Funding; Novartis Pharmaceuticals Corporation: Research Funding. Melenhorst:Novartis: Patents & Royalties, Research Funding; Incyte: Research Funding; Tmunity: Research Funding; Shanghai UNICAR Therapy, Inc: Consultancy; CASI Pharmaceuticals: Consultancy. Davis:Novartis Institutes for Biomedical Research, Inc.: Patents & Royalties. Schuster:Gilead: Membership on an entity's Board of Directors or advisory committees; Physician's Education Source, LLC: Honoraria; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; Nordic Nanovector: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Dava Oncology: Consultancy, Honoraria; Genentech: Honoraria, Research Funding; OncLive: Honoraria. Siegel:Novartis: Research Funding. Isaacs:Novartis: Employment. June:Immune Design: Membership on an entity's Board of Directors or advisory committees; Celldex: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceutical Corporation: Patents & Royalties, Research Funding; Tmunity Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Tmunity Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Immune Design: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceutical Corporation: Patents & Royalties, Research Funding. Porter:Kite Pharma: Other: Advisory board; Genentech: Other: Spouse employment; Novartis: Other: Advisory board, Patents & Royalties, Research Funding.