ALBERT

Description: Key Points The genetic cause of SCID impacts on survival and immune reconstitution and should be considered in tailoring HCT for individual patients. Total and naive CD4+ cell counts in SCID patients 6 and 12 months post-HCT predict long-term survival and sustained immune reconstitution.

Description: Pathogenic gain-of-function variants in the genes encoding phosphoinositide 3-kinase δ (PI3Kδ) lead to accumulation of transitional B cells and senescent T cells, lymphadenopathy, and immune deficiency (activated PI3Kδ syndrome [APDS]). Knowing the genetic etiology of APDS afforded us the opportunity to explore PI3Kδ inhibition as a precision-medicine therapy. Here, we report in vitro and in vivo effects of inhibiting PI3Kδ in APDS. Treatment with leniolisib (CDZ173), a selective PI3Kδ inhibitor, caused dose-dependent suppression of PI3Kδ pathway hyperactivation (measured as phosphorylation of AKT/S6) in cell lines ectopically expressing APDS-causative p110δ variants and in T-cell blasts derived from patients. A clinical trial with 6 APDS patients was conducted as a 12-week, open-label, multisite, within-subject, dose-escalation study of oral leniolisib to assess safety, pharmacokinetics, and effects on lymphoproliferation and immune dysregulation. Oral leniolisib led to a dose-dependent reduction in PI3K/AKT pathway activity assessed ex vivo and improved immune dysregulation. We observed normalization of circulating transitional and naive B cells, reduction in PD-1+CD4+ and senescent CD57+CD4− T cells, and decreases in elevated serum immunoglobulin M and inflammatory markers including interferon γ, tumor necrosis factor, CXCL13, and CXCL10 with leniolisib therapy. After 12 weeks of treatment, all patients showed amelioration of lymphoproliferation with lymph node sizes and spleen volumes reduced by 39% (mean; range, 26%-57%) and 40% (mean; range, 13%-65%), respectively. Thus, leniolisib was well tolerated and improved laboratory and clinical parameters in APDS, supporting the specific inhibition of PI3Kδ as a promising new targeted therapy in APDS and other diseases characterized by overactivation of the PI3Kδ pathway. This trial was registered at www.clinicaltrials.gov as #NCT02435173.

Description: Key Points Complete genome sequence analysis of 40 DLBCL tumors and 13 cell lines reveals novel somatic point mutations, rearrangements, and fusions. Recurrence of mutations in genes involved in B-cell homing were identified in germinal center B-cell DLBCLs.

Description: Seven patients with hematologic malignancy refractory to conventional therapy were treated with 1000 rads midpoint tissue dose of whole-body irradiation followed by infusion of marrow from an HL-A matched sibling. Three patients with advanced leukemia showed histologic evidence suggestive of engraftment but the graft did not function and they died after 18, 26, and 30 days. Four patients, three with acute lymphoblastic leukemia and one with Hodgkin’s disease, treated while in good clinical condition, showed evidence of a functioning marrow graft within 3 wk. Engraftment was proved by cytogenetic analysis in three cases with donors of the opposite sex. One patient died with graft-vs.-host disease (GVH) after 37 days. The other three had mild to moderate GVH. Two patients showed recurrent leukemia and died after 85 and 102 days. In one of these patients, a girl, the recurrent leukemia was in male donor cells. One patient, a boy, is alive and well after 200 days with only female donor cells in the marrow. He shows no evidence of GVH and, as yet, no leukemia.

Description: Abstract 404 To characterize the genomic events associated with distinct subtypes of AML, we used whole genome sequencing to compare 24 tumor/normal sample pairs from patients with normal karyotype (NK) M1-AML (12 cases) and t(15;17)-positive M3-AML (12 cases). All single nucleotide variants (SNVs), small insertions and deletions (indels), and cryptic structural variants (SVs) identified by whole genome sequencing (average coverage 28x) were validated using sample-specific custom Nimblegen capture arrays, followed by Illumina sequencing; an average coverage of 972 reads per somatic variant yielded 10,597 validated somatic variants (average 421/genome). Of these somatic mutations, 308 occurred in 286 unique genes; on average, 9.4 somatic mutations per genome had translational consequences. Several important themes emerged: 1) AML genomes contain a diverse range of recurrent mutations. We assessed the 286 mutated genes for recurrency in an additional 34 NK M1-AML cases and 9 M3-AML cases. We identified 51 recurrently mutated genes, including 37 that had not previously been described in AML; on average, each genome had 3 recurrently mutated genes (M1 = 3.2; M3 = 2.8, p = 0.32). 2) Many recurring mutations cluster in mutually exclusive pathways, suggesting pathophysiologic importance. The most commonly mutated genes were: FLT3 (36%), NPM1 (25%), DNMT3A (21%), IDH1 (18%), IDH2 (10%), TET2 (10%), ASXL1 (6%), NRAS (6%), TTN (6%), and WT1 (6%). In total, 3 genes (excluding PML-RARA) were mutated exclusively in M3 cases. 22 genes were found only in M1 cases (suggestive of alternative initiating mutations which occurred in methylation, signal transduction, and cohesin complex genes). 25 genes were mutated in both M1 and M3 genomes (suggestive of common progression mutations relevant for both subtypes). A single mutation in a cell growth/signaling gene occurred in 38 of 67 cases (FLT3, NRAS, RUNX1, KIT, CACNA1E, CADM2, CSMD1); these mutations were mutually exclusive of one another, and many of them occurred in genomes with PML-RARA, suggesting that they are progression mutations. We also identified a new leukemic pathway: mutations were observed in all four genes that encode members of the cohesin complex (STAG2, SMC1A, SMC3, RAD21), which is involved in mitotic checkpoints and chromatid separation. The cohesin mutations were mutually exclusive of each other, and collectively occur in 10% of non-M3 AML patients. 3) AML genomes also contain hundreds of benign “passenger” mutations. On average 412 somatic mutations per genome were translationally silent or occurred outside of annotated genes. Both M1 and M3 cases had similar total numbers of mutations per genome, similar mutation types (which favored C〉T/G〉A transitions), and a similar random distribution of variants throughout the genome (which was affected neither by coding regions nor expression levels). This is consistent with our recent observations of random “passenger” mutations in hematopoietic stem cell (HSC) clones derived from normal patients (Ley et al manuscript in preparation), and suggests that most AML-associated mutations are not pathologic, but pre-existed in the HSC at the time of initial transformation. In both studies, the total number of SNVs per genome correlated positively with the age of the patient (R2 = 0.48, p = 0.001), providing a possible explanation for the increasing incidence of AML in elderly patients. 4) NK M1 and M3 AML samples are mono- or oligo-clonal. By comparing the frequency of all somatic mutations within each sample, we could identify clusters of mutations with similar frequencies (leukemic clones) and determined that the average number of clones per genome was 1.8 (M1 = 1.5; M3 = 2.2; p = 0.04). 5) t(15;17) is resolved by a non-homologous end-joining repair pathway, since nucleotide resolution of all 12 t(15;17) breakpoints revealed inconsistent micro-homologies (0 – 7 bp). Summary: These data provide a genome-wide overview of NK and t(15;17) AML and provide important new insights into AML pathogenesis. AML genomes typically contain hundreds of random, non-genic mutations, but only a handful of recurring mutated genes that are likely to be pathogenic because they cluster in mutually exclusive pathways; specific combinations of recurring mutations, as well as rare and private mutations, shape the leukemia phenotype in an individual patient, and help to explain the clinical heterogeneity of this disease. Disclosures: Westervelt: Novartis: Speakers Bureau.

Description: Key Points Donor-derived Tc17 cells differentiate early after allogeneic transplant in response to IL-6 and alloantigen presentation by host DCs. Tc17 are highly proinflammatory and pathogenic posttransplant, but exert limited or no GVL activity.

Description: Background: CD19-directed chimeric antigen receptor (CAR) T cell therapy is FDA approved for relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL) and variants. Due to active lymphoma, "bridging" therapy may be needed to maintain disease control during the 3 or more weeks required for autologous CAR T manufacturing. Bridging therapy was not allowed in trials of axicabtagene ciloleucel (axi-cel), but could improve outcomes by reducing tumor burden. Bridging chemotherapy is one option, however toxicity and chemo-refractory disease are potential concerns. Here we report a case series of patients receiving bridging radiation therapy (XRT) prior to axi-cel therapy, of which the majority had double hit lymphoma. Patient Characteristics: As of July 31, 2018 eight patients received XRT as part of their bridging therapies. Overall, patients had a median of 3 prior lines of chemotherapy (range 2 to 5). Two were primary refractory to their first two lines of chemotherapy. Six of the 8 patients had double hit lymphoma by FISH. All patients received 3-4 Gy per fraction to a total median dose of 20 Gray (range 9 - 30 Gy). The most commonly used regimen was 30 Gy in 10 fractions (3/7 patients). Four patients received bridging chemotherapy in addition to XRT, mainly oral cytoxan. In 2 patients the XRT was given up until the day of leukapheresis and in 1 of these patients it was continued after leukapheresis. In 6 additional patients the XRT started after leukapheresis. Overall, XRT was completed at a median of 9 days (range 3 - 22 days) prior to starting Flu/Cy conditioning. The median mass diameter receiving XRT was 13.6 cm (range 3 - 30 cm). Outcomes: No significant adverse events were noted at the local site of XRT before or after CAR T infusion. Response assessment within the field of radiation is complicated by a short duration between end of XRT and restaging prior to Flu/Cy conditioning. Nonetheless, only one patient experienced progressive disease in-field after XRT and most had stable disease in-field. Of the 4 cases where the baseline LDH was elevated, only the patient with PD saw their LDH rise after the completion of XRT, while the other 3 of 4 patients had declining LDH at the time of Flu/Cy conditioning. In 7 patients evaluable for toxicity, there was one case of severe cytokine release syndrome (CRS). This event occurred in the patient who progressed through XRT and had rising LDH and declining performance status prior to CAR T infusion (this patient later died of infection). In the other 6 patients the maximum CRS was grade 1 or 2. Three out of the 7 patients had grade 3 or 4 CAR T related encephalopathy syndrome (CRES). For lymphoma outcomes at day 30, 1 patient was in CR, 2 patients PR, 2 patients with SD and 1 patient with PD (Lugano criteria). Two patients are evaluable at day 90 with PR, although one of these patients subsequently relapsed at month 4 (in-field to the prior radiation). Conclusions: Bridging XRT (with or without chemotherapy) can be safely administered and provides disease control in refractory poor risk DLBCL patients prior to axi-cel therapy. All patients were able to receive axi-cel. CAR T-related toxicity occurred, but in this case series was most likely related to disease aggressiveness (6 of 8 patients were double hit) and tumor burden. Further research should focus on the immunologic effects of XRT and its impact on CAR T cell efficacy and toxicity. Table. Table. Disclosures Chavez: Humanigen: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Speakers Bureau; Merck: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Davila:Celyad: Consultancy, Membership on an entity's Board of Directors or advisory committees. Locke:Cellular BioMedicine Group Inc.: Consultancy; Kite Pharma: Other: Scientific Advisor; Novartis Pharmaceuticals: Other: Scientific Advisor.

Description: Abstract 99 Whole genome sequencing with next generation technologies represents a new, unbiased approach for discovering somatic variations in cancer genomes. Our group recently reported the DNA sequence and analysis of the genomes of two patients with normal karyotype acute myeloid leukemia (AML). Improvements in next generation sequencing technologies (principally, paired-end sequencing) led us to reevaluate the first case (Ley et al, Nature 456:66–72, 2008) with deeper sequence coverage. We discovered a novel frameshift mutation in DNMT3A, one of the three genes in humans (DNMT1, DNMT3A, and DNMT3B) that encodes a DNA methyltransferase that catalyzes the addition of methyl groups to cytosine within CpG dinucleotides. We then sequenced all the coding exons of this gene in 280 additional de novo cases of AML to define recurring mutations. 62/281 de novo AML cases (22%) had mutations with translational effects in the DNMT3A gene. 18 different missense mutations were identified, the most common of which was at amino acid R882 (37 cases). Frameshifts (n=6), nonsense mutations (n=6), splice site mutations (n=3), and a 1.5 Mbp deletion that included the DNMT3A gene were also identified. DNMT3A mutations were highly enriched in cases with intermediate risk cytogenetics (56/166=33.7%; p

Description: Background: Therapy for patients (pts) with high risk and/or relapsed or refractory AML remains unsatisfactory. Retrospective studies have demonstrated activity of fludarabine, cytarabine, granulocyte colony stimulating factor and idarubicin (FLAG-IDA) as salvage therapy in pts with relapsed or refractory AML. Furthermore, a recent randomized trial has indicated high complete remission (CR) rates with improved relapsed-free survival when FLAG-IDA is administered as frontline induction chemotherapy (Burnett et al. J Clin Oncol 2013). Therefore, since January 2011, we have employed FLAG-IDA as first line therapy in pts with high risk AML (i.e. poor risk cytogenetics, antecedent myeloproliferative neoplasm or myelodysplastic syndrome, or therapy-related AML), or as first salvage in pts with primary refractory or relapsed AML, in an attempt to improve CR rates and permit more patients with AML to advance to allogeneic hematopoietic stem cell transplantation (alloSCT). Methods: A retrospective review was conducted of the 62 consecutive patients with high risk AML or primary refractory or relapsed AML treated with FLAG-IDA between January 2011 to December 2013 at the Princess Margaret Cancer Centre to determine the CR rate and overall survival (OS) associated with FLAG-IDA remission induction chemotherapy. Results: Baseline characteristics of the patients are listed in Table 1. Fourteen pts received FLAG-IDA as first induction, whereas 48 pts received FLAG-IDA as salvage (39 as first salvage and 9 as second salvage). The overall CR rate (i.e. CR + CR with incomplete platelet recovery [CRi]) using FLAG-IDA as frontline therapy was assessed in 13 patients, as one pt died during induction therapy and therefore, was not evaluable. Of the 13 evaluable patients, all achieved CR or CRi. The overall CR rate for the salvage induction group was 73% (i.e. 31% CR and 42% CRi). The CR duration was censored at time of transplant. The CR duration for pts receiving FLAG-IDA as first induction was 3 mos (range, 0-15 mos). For pts receiving FLAG-IDA as salvage therapy, the CR1 duration for primary refractory AML pts was 6 mos (range, 2-58 mos) and CR2 duration for relapsed AML pts was 4 mos (range, 1-12 mos). 76% of patients (n=10) who received frontline FLAG-IDA induction chemotherapy, and achieved CR/CRi, had a donor identified, but only 40% of those pts underwent alloSCT. 85% of pts (n=30) who received salvage FLAG-IDA, and achieved CR/CRi, had a donor identified, but only 53% of those pts proceeded to alloSCT. The length of hospital stay during the first FLAG-IDA induction was 33 days (range, 17-96 days), whereas the length of hospital stay for salvage FLAG-IDA induction was 43 days (range, 10-305 days). Fourteen percent of pts in the first induction group were admitted to the ICU during their induction, compared to 17% of pts in the salvage induction group. The median ICU stay was 39.5 days and 14 days, respectively. There was a 14% death rate during FLAG-IDA induction for both groups. The median follow up time from diagnosis for both groups was 15.28 mos (range, 2-70.4 mos). Overall survival at 1 and 2 years in the upfront FLAG-IDA induction group was 65% and 41%, respectively, while OS at 1 and 2 years for the salvage FLAG-IDA group was 60% and 35%, respectively. Conclusions: The toxicities associated with FLAG-IDA induction, including induction death rates and ICU admission rates, are acceptable and similar in the untreated and heavily pre-treated groups. FLAG-IDA induction can result in durable CR rates, permitting patients with high risk AML or patients with primary refractory or relapsed AML to proceed to allogeneic transplantation. Table 1: Patient Characteristics Front-LineN=14 SalvageN=48 Median age, y (range) ≥70y (%) ≥60y (%) 65.5 (21-76) 2 (14%) 10 (71%) 50 (18-76) 2 (4%) 10 (21%) Gender 7M : 7F 22M : 26F Secondary/Therapy-related Prior MDS Prior MPN 14 (100%) 2 (14%) 2 (14%) 17 (35%) 8 (17%) 2 (4%) Cytogenetic risk group Good Intermediate Poor 0 4 (28%) 10 (71%) 3 (6%) 28 (58%) 17 (35%) Molecular abnormalities cKit mutated FLT3-ITD mutated 0 1 (7%) 2 (4%) 5 (10%) Median no. prior treatment regimens (range) 0 1 (1-2) Prior chemotherapy regimen Daunorubicin + cytarabine NOVE-HiDAc Other NA NA NA 43 (90%) 11 (23%) 3 (6%) Disease status Primary refractory Relapsed CR1 duration

Description: Introduction: Aggressive chemo-immunotherapy followed by peripheral blood stem cell autografting (ASCT) in CALGB 59909 achieved a median progression-free survival (PFS) in MCL of 5 years (Damon et al JCO, 2009), but late recurrences occurred. Bortezomib has a 33% response rate in relapsed/refractory MCL. Using the CALGB 59909 treatment backbone, we evaluated tolerability and efÞcacy of adding post-transplant BC or BM in a randomized phase II trial. Methods: The primary endpoint was PFS estimated from study entry for each treatment arm. Induction therapy was with 2-3 cycles of augmented R-CHOP (2000 mg/m2 cyclophosphamide) and methotrexate (300 mg/m2) followed by high-dose cytarabine/etoposide/rituximab(R)/Þlgrastim (EAR) stem cell mobilization and cyclophosphamide/carmustine/etoposide (CBV) ASCT. After 2 doses of post-transplant R, patients were randomized to BC (1.3 mg/ m2 days 1, 4, 8, 11 of a 3 week cycle for 4 cycles) or BM (1.6 mg/m2 weekly 4 of 8 weeks for 18 months) beginning at approximately day 90. Minimal residual disease (MRD) was analyzed using patient-specific PCR probes for the bcl-1 / IgH junction or the IgH CDR3 region. Results: 151 patients were enrolled at 14 sites and 147 received treatment. Median age was 59 (29-69); stage II (2.7%), III (12%), IV (86%); MIPI low (52.4%), int. (30.6%), high (17%); blastoid histology (14%); bone marrow involvement (81%). 118 (88%) underwent ASCT and 102 (68%) were randomized. Most withdrawals (45) were for progression (10) or adverse events (AEs) (19) including 4 treatment-related deaths. Following randomization, 34 (65%) completed BM and 33 (66%) completed BC. Withdrawal for AEs occurred in 14 (28%) of BC and 7 (13%) of BM patients (p = 0.088), most for cytopenias or peripheral neuropathy. Median follow-up was 5.5 years from registration. Median PFS was significantly greater than the null hypothesis (4 years) for both BM and BC (1-sided test of exponential parameter p 〈 0.001). The 5-year PFS estimates from study entry in the BM and BC arms were 70% (55-81%) and 69% (54-80%), respectively. Progression occurred in 17 BM (12 post-treatment) and 19 BC patients (all post-treatment). Five-year PFS from time of transplantation in CALGB studies 50403 (n=118) and 59909 (n=66) was 72.7% (63-80%) and 51.5% (36.7-62%), respectively (log rank p=0 0006) favoring the 50403 trial which differed from 59909 only by the addition of post-transplant bortezomib. MRD results were available in 47 patients. Five-year PFS from study entry was 93% if MRD-negative (n=15) and 51% if MRD-positive (n=32) following induction chemo-immunotherapy (log rank p=.003) (See figure). Conclusions: Induction chemotherapy followed by ASCT and either BC or BM was efficacious and tolerable, although BC was associated with more withdrawals for toxicity. The comparison between studies 50403 and 59909 suggests a PFS benefit from the addition of BC or BM. MRD-negativity following induction chemo-immunotherapy is highly associated with improved PFS and could provide an important tool for designing future trials. Figure 1. Figure 1. Disclosures Off Label Use: Post-autotransplant use of bortezomib . Bartlett:Seattle Genetics: Consultancy, Research Funding; Gilead: Consultancy; Janssen: Research Funding; Pharmacyclics: Research Funding; Astra Zeneca: Research Funding; ImaginAB: Research Funding; Genentech: Research Funding; Pfizer: Research Funding; Novartis: Research Funding; Medimmune: Research Funding; Millenium: Research Funding; Celgene: Research Funding. Byrd:Acerta Pharma BV: Research Funding. Blum:cephalon: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Pharmacyclics: Research Funding. Hurd:Procter and Gamble: Equity Ownership; Medtronic: Equity Ownership; Pfizer: Equity Ownership; Merck: Equity Ownership; Bristol Myers Squib: Equity Ownership. Czuczman:MorphoSys: Consultancy; Cellgene: Employment; Immunogen: Membership on an entity's Board of Directors or advisory committees; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees. Leonard:Weill Cornell Medical College: Employment; Genentech: Consultancy; Medimmune: Consultancy; AstraZeneca: Consultancy; Spectrum: Consultancy; Boehringer Ingelheim: Consultancy; Vertex: Consultancy; ProNAI: Consultancy; Biotest: Consultancy; Seattle Genetics: Consultancy; Pfizer: Consultancy; Mirati Therapeutics: Consultancy; Gilead: Consultancy; Novartis: Consultancy. Cheson:AstraZeneca: Consultancy; Astellas: Consultancy; Ascenta: Research Funding; Spectrum: Consultancy; Teva: Research Funding; MedImmune: Research Funding; Pharmacyclics: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Roche/Genentech: Consultancy, Research Funding; Celgene: Consultancy, Research Funding.