Abstract: Introduction: Venetoclax (VEN) is a highly effective agent for chronic lymphocytic leukemia (CLL) that targets BCL-2. Thus, it has been hypothesized to have efficacy in NHL and tested in phase-1/2 studies (Gerecitano JF, Blood 2015; de Vos S, Blood 2015; Davids MS, J Clin Oncol 2017). Overall response rates (ORR) observed in r/r NHL were 44% for all subtypes combined, 38% for follicular lymphoma (FL), 75% for mantle cell lymphoma (MCL), and 18% for diffuse large B-cell lymphoma (DLBCL). The adverse effect profile was consistent with the labeling despite dose escalation to doses higher than used in CLL. Additionally, VEN is a potential option in the r/r NHL setting, potentially providing less T cell toxicity compared to other agents used as bridging to T-cell therapies (Cummins NW, mBio, 2016; Dzhagalov I, J Immunol, 2008). We performed an analysis of all NHL patients (pts) treated with VEN at our institution to assess efficacy and safety of VEN in r/r NHL. Patients and Methods: We conducted a retrospective cohort study of all adult pts who received VEN for r/r NHL at the University of Pennsylvania between 4/2016 and 6/2018. Demographics, tumor lysis syndrome (TLS; events, prophylaxis and management), duration of therapy, reason for discontinuation, overall response, survival, and toxicities were examined. The primary endpoints were progression-free survival (PFS; defined as time from VEN start to disease progression or regimen change, death due to NHL or last-follow-up in remission), and overall survival using the Kaplan-Meier method. All other analyses were descriptive. Results: We identified 23 NHL pts for this analysis. NHL subtypes included DLBCL (35%; n=8), MCL (30%; n=7), Richter transformation (RT) (9%; n=2), transformed FL (tFL) (12%; n=4), post-transplant lymphoproliferative disease (PTLD) (4%; n=1), and marginal zone lymphoma (MZL; n=1) (4%). Median age at VEN start was 65 years; most pts were Ann Arbor stage IV (87%) and ECOG performance 2-4 (57%). NHL characteristics were MYC rearrangement (35%), BCL2 rearrangement (22%), double-hit lymphoma (26%), BCL2 IHC+ (22%), non-germinal center phenotype (13%). Median number of prior therapies was 4 (range: 2-13) with 17% having a prior autologous stem cell transplant. Median time to VEN initiation from prior therapy was 1 month (range, 0.5-9). Median VEN dose achieved was 400 mg (Range, 100-1200). Data for TLS are in Table 1. Median time on VEN was 2 months. While on VEN, 17% received radiation and 43% were on other anti-neoplastic therapy. Overall response rate (ORR) for the entire cohort was 26% (100% Partial Response [PR]). Subtypes with PR included MCL (13%), DLBCL (9%), and RT (4%). No PRs were observed with tFL, PTLD, nor MZL. Pts most commonly discontinued VEN for disease progression (74%); 2 pts (9%) remain on VEN therapy (range: 2-11 months). Median PFS and OS for the entire cohort were 2 months and 3 months, respectively, (Figure 1). Analyzed as histologic cohorts, large B-cell lymphomas (DLBCL, RT, PTLD, tFL) had similar median PFS and OS. However, small B-cell lymphomas (MCL, MZL) had median PFS and OS of 2.5 and 4 months, respectively. Two pts subsequently received CAR T-cell therapy post-VEN; one collected T-cells during VEN therapy and one collected T-cells prior to VEN start. Adverse events (AEs) occurred in approximately 65% while on VEN. AEs included: neutropenia (48%), thrombocytopenia (43%), TLS (30%), infection (26%), neutropenic fever (26%), and diarrhea (22%). One pt had an opportunistic infection (Pneumocystis jiroveci pneumonia) while on VEN and concurrent high-dose steroids. Conclusion: VEN monotherapy appears effective for NHL in phase I clinical trials. We describe our experience outside the setting of a clinical trial, including VEN used as part of multi-agent salvage therapy. Median PFS for our entire cohort is 2 months; AEs, while expected, were observed frequently, reflecting comorbidities. Clinical TLS events are attributed to pre-existing renal dysfunction (61% below 80 mL/min) during VEN escalation. The wide heterogeneity of VEN dose escalation, multi-agent combinations, and timing of initiation of VEN therapy are factors that require further investigation best designed as prospective clinical trials using other agents in combination with VEN. Disclosures Landsburg: Takeda: Consultancy; Curis: Consultancy, Research Funding. Schuster:Genentech: Honoraria, Research Funding; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; 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; Merck: Consultancy, Honoraria, Research Funding; OncLive: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Consultancy, Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees; Physician's Education Source, LLC: Honoraria. Svoboda:Pharmacyclics: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; TG Therapeutics: Research Funding; Seattle Genetics: Consultancy, Research Funding; Regeneron: Research Funding; KITE: Consultancy; Kyowa: Consultancy; Merck: Research Funding. Gill:Novartis: Research Funding; Extellia: Consultancy, Membership on an entity's Board of Directors or advisory committees; Carisma Therapeutics: Equity Ownership. Mato:TG Therapeutics: Consultancy, Research Funding; AstraZeneca: Consultancy; Portola: Research Funding; Johnson & Johnson: Consultancy; Regeneron: Research Funding; Acerta: Research Funding; Celgene: Consultancy; Prime Oncology: Honoraria; Pharmacyclics, an AbbVie Company: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Medscape: Honoraria. Altman:Epizyme: Other: payment to the institution to conduct clinical trial work; Incyte: Other: payment to the institution to conduct clinical trial work; Agios: Other: Payment to the institution to conduct the trial ; Pfizer: Other: payment to the institution to conduct clinical trial work; Ariad: Other: payment to the institution to conduct clinical trial work; BMS: Membership on an entity's Board of Directors or advisory committees; Astellas Pharma: Other; GSK: Other: payment to the institution to conduct clinical trial work; Boeringer Ingelheim: Other: payment to the institution to conduct clinical trial work; FujiFilm: Other: payment to the institution to conduct clinical trial work; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: payment to the institution to conduct clinical trial work; Bayer: Other: payment to the institution to conduct clinical trial work; Celator: Other: payment to the institution to conduct clinical trial work; Cyclacel: Other: payment to the institution to conduct clinical trial work; Syros: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Genetech: Other: Payment to the institution to conduct clinical trial work; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Immune Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Dwivedy Nasta:Pharmacyclics: Research Funding; Incyte: Research Funding; Roche: Research Funding; Aileron: Research Funding; Rafael/WF: Research Funding; Debiopharm: Research Funding; Merck: Other: DSMC; Takeda/Millenium: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract: Background: Cellular therapy using anti-CD19 autologous chimeric antigen receptor modified T (CART19) cells demonstrates promising outcomes in several hematologic malignancies of B-cell origin, but this therapy has not been studied in HL patients (pts). While neoplastic HL Reed-Sternberg (HRS) cells are considered CD19 negative, circulating CD19 positive clonal HRS cell precursors and CD19 positive reactive cells within the HRS tumor microenvironment represent potential therapeutic targets for CART19 in HL. Methods: We designed companion pediatric (NCT02624258) and adult (NCT02277522) open-label pilot studies to estimate the feasibility, safety, and efficacy of CART19 cell infusions in pts with relapsed/refractory HL lacking curative treatment options. To allow transient CD19 targeting and limit the window for acute toxicity and B cell aplasia, we used autologous T-cells electroporated with mRNA encoding chimeric anti-CD19 immunoreceptor scFv (RNA CART19) cells in lieu of permanently modified cells engineered by viral transduction. The scFv is derived from a murine monoclonal antibody. Following pheresis and manufacturing of RNA CART19 cells, pts undergo up to 6 infusions of 8x105-1.5x106 RNA CART19 cells/kg/dose for pts & lt;80kg and 1x108 RNA CART19 cells/dose (±20%) for pts ≥80kg. Intravenous cyclophosphamide (30mg/kg) is administered prior to the first and fourth infusion to enhance engraftment. Safety, response assessments (Cheson 2007 criteria), and ancillary studies are measured at defined time points. The primary objective is to describe manufacturing feasibility, safety, and persistence of RNA CART19 cells in HL. Secondary objectives are to estimate efficacy by overall response rates (ORR) and the effect of RNA CART19 on immune factors. Results: To date, 5 pts have been enrolled and had RNA CART19 manufactured. Four pts were infused with RNA CART19 and are evaluable for toxicity/response. Characteristics of the 5 pts include: median age 24 years (range 21-42), 4 (80%) with stage IV, median number of previous therapies 5 (range 4-9), 4 (80%) had stem cell transplant (SCT): 3 had auto SCT, 1 had both auto and allo SCT. Three pts previously progressed on PD-1 inhibitor. All 5 pts underwent successful manufacturing of RNA CART19. One pt developed MDS prior to RNA CART19 infusions and was taken off study. Four patients who underwent RNA CART19 infusions were treated with cyclophosphamide as per protocol. The median number of infused CART19 cells/kg/dose was 1.5x106 (range 7.3x105 -1.5x106). Each patient (pt) received 6 infusions over 2 weeks. Using qRT-PCR, RNA CART19 was detected in 80% of peripheral blood samples drawn within 2 hours after each infusion (Figure 1). RNA CART19 was also detected in 20% of samples drawn immediately prior each infusion reflecting persistence of RNA CART19 from previous infusion at 48 or more hours ago. No pt had RNA CART19 detected by Day (D) 21. There were no study related deaths or grade (G) 3/4 non-hematologic toxicities. Most common G1/2 toxicities at least possibly related to the RNA CART19 therapy occurring in & gt; 1 pt included transient headache in 3 and insomnia in 2. There was no evidence of cytokine release syndrome or significant elevation in cytokines at any point. The ORR at D28 was 50%: 1 complete (CR) and 1 partial response (PR). One pt had stable disease (SD) and one pt had progressive disease (PD). The CR pt (#3) was noted to have persistent RNA CART19 cells in 3 samples drawn at about 48 hours after the prior infusion compared with the PD pt (#1) who had no RNA CART19 detected by this time point on any measurement. In 2 pts who responded (#3 and #4), number of CD19-positive B-cells by flow cytometry as % of total leukocytes declined by 50% on D28 when compared to baseline. There was no evidence of B cell aplasia. The pt in CR progressed at 3 months and the pt in PR was taken off study. As part of routine clinical care, the 2 responding pts (#3 and #4) are currently in CR on PD-1 inhibitor (one underwent auto SCT). The pt with SD is in PR on lenalidomide and the pt with PD died of disease progression. Conclusion: Targeting CD19 positive cells with non-viral, RNA-electroporated, transiently expressed CART19 cells is a feasible and safe strategy in pts with relapsed/refractory HL. We saw encouraging responses, but these were short-lived. We are planning a study for HL pts utilizing virally transduced CART19 cells that are capable of in vivo expansion in combination with PD-1 inhibitors. Disclosures Svoboda: Merck: Research Funding; BMS: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Celgene: Research Funding; Kite: Consultancy; Pharmacyclics: Research Funding. Gill: Novartis Pharmaceuticals: Patents & Royalties, Research Funding. Grupp: Adaptimmune: Consultancy; University of Pennsylvania: Patents & Royalties; Jazz Pharmaceuticals: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy, Other: grant. Lacey: Novartis: Research Funding; Genentech: Honoraria. Melenhorst: Novartis: Research Funding. Mato: DTRM: Research Funding; AstraZeneca: Consultancy; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Regeneron: Research Funding; Acerta: Research Funding; Portola: Research Funding; Kite: Consultancy; AbbVie: Consultancy, Research Funding; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy. Dwivedy Nasta: Takeda: Research Funding; Incyte: Research Funding; Immunogen: Research Funding. Landsburg: Takeda: Research Funding; Curis: Consultancy, Research Funding. Levine: GE Healthcare: Consultancy; Tmunity Therapeutics: Equity Ownership, Research Funding; Brammer Bio: Consultancy; Novartis Pharmaceuticals Corporation: Patents & Royalties, Research Funding. Porter: Immunovative Therapies: Other: Member DSMB; Novartis: Honoraria, Patents & Royalties, Research Funding; Genentech/Roche: Employment, Other: Family member employment, stock ownship - family member; Servier: Honoraria, Other: Travel reimbursement; Incyte: Honoraria. June: Novartis: Patents & Royalties, Research Funding; Tmunity Therapeutics: Equity Ownership, Research Funding; WIRB/Copernicus Group: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celldex: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immune Design: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Schuster: Genentech: Consultancy, Research Funding; Merck: Research Funding; Celgene: Consultancy, Research Funding; Nordic Nanovector: Consultancy; Novartis: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Seattle Genetics: Consultancy; Gilead: Consultancy, Research Funding; Janssen: Consultancy, Honoraria.

Abstract: Manufacturing CART19 by transfecting autologous T cells with messenger RNA is feasible. Targeting CD19+ B cells in cHL using nonviral RNA CART19 was well tolerated and resulted in transient responses in a pilot study.

Abstract: Background: Synthetic lethality (SL) is characterized by the chemical inhibition of multiple aberrant genes to differentially kill malignant cells. We investigated small-molecule combinations for SL through in vitro and in vivo screening and optimization studies (as in the granted patents in USA and China) and demonstrated the synergistic potential of best-in-class combinations of targeted agents, drug repositioning, immune modulation and low-dose combinations. We hypothesize that BTK and mTOR inhibition coupled with an IMID will target multiple key signaling pathways, improve differential apoptosis and target acquired drug resistance. DTRM-555, an optimized mechanism-based combination, consists of the clinically differentiated BTK inhibitor DTRMWXHS-12 (or DTRM-12), everolimus (EV) and pomalidomide (POM). In xenograft tumor models, DTRM-555 administered orally has demonstrated superior efficacy over monotherapy at very low dose combinations of the three agents (1/18 of DTRM-12, 1/6 of EV, and 1/6 of POM). DTRM-12 monotherapy has been safe and well tolerated in simultaneous phase Ia trials (US and China) with preliminary efficacy across 50 mg through 400 mg once daily (QD). Here we report the US clinical results of the oral combination therapies DTRM-505 (DTRM-12 plus EV) and DTRM-555 (DTRM-12 plus EV plus POM) for the first time (NCT02900716). Methods: The safety and anti-tumor activity of the oral doublet therapy DTRM-505 and the oral triplet therapy DTRM-555 are evaluated using a "3+3" study design. Enrollment was conducted concurrently with a phase Ia study of DTRM-12 monotherapy; with DTRM-505 opened for accrual when monotherapy DTRM-12 cleared the 200-mg dose level. Eligible patients are at least 18 years old, having ECOG performance status less than 2 with relapsed/refractory chronic lymphocytic leukemia (CLL), diffuse large B cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular lymphoma (FL) or classical Hodgkin lymphoma (cHL). Study treatment is administered daily for 21 consecutive days over a 28-day cycle. The dose-limiting toxicity (DLT) period was defined during the first cycle of therapy, and treatment was continued until disease progression or unacceptable toxicity. Patients underwent tumor evaluations every 2 months and response was recorded using revised response criteria (IWCLL and Cheson 2014). Results: Between 9/2016 and 7/2018, 19 patients have been treated with DTRM-12 monotherapy in the USA (6 pts, 50-300 mg) and China (13 pts, 50-400 mg). Patients have tolerated up to 23+ cycles of DTRM-12 monotherapy. Seven patients, including DLBCL, CLL, MCL, FL and cHL, have been treated with oral doublet therapy DTRM-505 for 2 to 12 cycles. Three patients (2 DLBCL, 1 FL) have been treated with oral triplet therapy DTRM-555, including one patient transitioned from the doublet DTRM-505 under an exploratory arm. No patient has discontinued due to an adverse event (AE) and no DLT has occurred. Recurring AEs are mostly grade 1 or 2 and responses have been seen with DTRM-505 and DTRM-555 across diverse lymphoma histologies (See Tables). All patients evaluable for response demonstrated partial response to DTRM-505 and DTRM-555, with 2/7 (doublet) and 3/3 (triplet) patients remaining on therapy. Conclusion: The maximum tolerated dose has not been reached for DTRM-12 monotherapy and for the current fixed dose doublet and triplet combinations. Toxicities have been mild and repeated cycles of study treatment have been well tolerated without delays of subsequent treatment cycles. Enrollment continues for refractory lymphoma patients to demonstrate the safety and efficacy for the first-in-class oral triplet therapy DTRM-555. Disclosures Huntington: Janssen: Consultancy; Bayer: Consultancy; Celgene: Consultancy. Schuster:Merck: Consultancy, Honoraria, Research Funding; Genentech: Honoraria, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; OncLive: Honoraria; Dava Oncology: Consultancy, Honoraria; Physician's Education Source, LLC: Honoraria; 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; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees. He:Zhejiang DTRM Biopharma Co. Ltd.: Other: Founder and CEO; Zhejiang DTRM Biopharma LLC: Other: Founder and CEO. Shen:Zhejiang DTRM Biopharma LLC: Other: Clinical Operations Director. Kennard:AbbVie, Gilead, Verastem: Consultancy. Dwivedy Nasta:Incyte: Research Funding; Takeda/Millenium: Research Funding; Debiopharm: Research Funding; Pharmacyclics: Research Funding; Rafael/WF: Research Funding; Aileron: Research Funding; Roche: Research Funding; Merck: Other: DSMC; Celgene: Membership on an entity's Board of Directors or advisory committees. Landsburg:Takeda: Consultancy; Curis: Consultancy, Research Funding. Porter:Novartis: Other: Advisory board, Patents & Royalties, Research Funding; Genentech: Other: Spouse employment; Kite Pharma: Other: Advisory board. Svoboda:Bristol-Myers Squibb: Consultancy, Research Funding; TG Therapeutics: Research Funding; Kyowa: Consultancy; Regeneron: Research Funding; Merck: Research Funding; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; KITE: Consultancy. Song:Peking University Cancer Hospital (Beijing Cancer Hospital): Employment. Zhu:Beijing Cancer Hospital: Employment. Brander:Pharmacyclics, an AbbVie Company: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; TG Therapeutics: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; Novartis: Consultancy, Other: DSMB; Genentech: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; Teva: Consultancy, Honoraria; Acerta: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; DTRM: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; BeiGene: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding. Ding:Merck: Research Funding. Mato:Pharmacyclics, an AbbVie Company: Consultancy, Research Funding; AstraZeneca: Consultancy; Regeneron: Research Funding; Celgene: Consultancy; Acerta: Research Funding; TG Therapeutics: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Portola: Research Funding; Johnson & Johnson: Consultancy; Prime Oncology: Honoraria; Medscape: Honoraria.

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.

Abstract: Background: Wilms’ tumour gene 1 (WT-1) is frequently over-expressed in adult AML and may be of prognostic value. We examined the prognostic utility of WT-1 expression in the peripheral blood, measured by RQ-PCR on diagnostic specimens, and characterised this compared to other clinical and biological predictors of survival. Methods: RQ-PCR was performed in triplicate on samples from newly diagnosed AML patients, using the Corbett Rotorgene 3000. Values were averaged and levels expressed relative to 104 ABL copies. Multivariate stratified Cox regression, with the stratification variable cytogenetic risk group and WT-1 levels analysed as a continuous variable, was used to model the outcomes of overall survival (OS) and event free survival (EFS). Results: Samples were collected from 58 patients with AML. The median age was 66 years (range 16–82) and 30 were male. Seven had antecedent haematological disorders and 9 had received prior chemo/radiotherapy. Induction therapy was with cytarabine based regimens in 18, high dose cytarabine regimens in 20, ATRA/chemotherapy in 6 and supportive care in 14. Complete remission was achieved in 64% with 18% induction mortality. Median OS was 4 months (17 months in responders) and 27% at 2 years. The median WT-1 transcript level in diagnostic AML samples was 5122 (range 9–36125), while in normal control samples it was 3 (n=11, mean 3.6, SD 1.6). In multivariate Cox regression, stratified by cytogenetic risk group, age (p 〈 0.001), LDH (p 〈 0.001) and performance status (p=0.04) retained prognostic significance for OS and EFS. Elevated peripheral blood WT1 levels were significantly associated with impaired OS (HR 1.24 per log10 transcript levels p=0.022) and EFS (HR 1.31 per log10 transcript levels p=0.0019). WT1 levels correlated with cytogenetic risk group (p=0.002 with higher levels seen in the favourable risk group), antecedent haematological disorder (p=0.05), peripheral blood blast percentage (p=0.05) and bone marrow blast percentage (p=0.01). WT1 levels were significantly higher in acute promyelocytic leukaemia (p=0.0001) compared to other AML subtypes. WT1 levels did not correlate with age (p=0.16), sex (p=0.12), prior chemo/radiotherapy (p=0.96), performance status (p=0.33) or LDH (p=0.91). Conclusions: WT1 RQ-PCR levels are frequently elevated in peripheral blood from patients with AML at diagnosis and are associated with subtype, cytogenetic risk group, blast percentage and antecedent haematological disorder. Within specified cytogenetic risk groups, elevated WT1 levels may predict AML patients at high risk of relapse and subsequent mortality.

Abstract: In chronic lymphocytic leukemia (CLL) patients who achieve a complete remission (CR) to anti-CD19 chimeric antigen receptor T cells (CART-19), remissions are remarkably durable. Preclinical data suggesting synergy between CART-19 and the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib prompted us to conduct a prospective single-center phase 2 trial in which we added autologous anti-CD19 humanized binding domain T cells (huCART-19) to ibrutinib in patients with CLL not in CR despite ≥6 months of ibrutinib. The primary endpoints were safety, feasibility, and achievement of a CR within 3 months. Of 20 enrolled patients, 19 received huCART-19. The median follow-up for all infused patients was 41 months (range, 0.25-58 months). Eighteen patients developed cytokine release syndrome (CRS; grade 1-2 in 15 of 18 subjects), and 5 developed neurotoxicity (grade 1-2 in 4 patients, grade 4 in 1 patient). While the 3-month CR rate among International Working Group on CLL (iwCLL)-evaluable patients was 44% (90% confidence interval [CI], 23-67%), at 12 months, 72% of patients tested had no measurable residual disease (MRD). The estimated overall and progression-free survival at 48 months were 84% and 70%, respectively. Of 15 patients with undetectable MRD at 3 or 6 months, 13 remain in ongoing CR at the last follow-up. In patients with CLL not achieving a CR despite ≥6 months of ibrutinib, adding huCART-19 mediated a high rate of deep and durable remissions. ClinicalTrials.gov number, NCT02640209.

Abstract: Introduction: The bruton tyrosine kinase (BTK) inhibitor ibrutinib demonstrates considerable activity in mantle cell lymphoma (MCL). However, approximately 30% of patients do not respond to this treatment and the therapy invariably leads to drug resistance with a median response of 17.5 months. Infusion of autologous T cells transduced with chimeric antigen receptors (CAR) against the B-cell specific CD19 antigen (CART19) leads to dramatic clinical responses in the majority of patients with acute lymphoblastic leukemia and the activity in B cell lymphoma is currently being evaluated in clinical trials. Bulky disease, as sometimes seen in MCL, may impair T cell infiltration. The features of ibrutinib that make it an interesting addition to CART19 include its efficacy in reducing tumor masses and its ability to mobilize neoplastic B cells into the peripheral blood, thereby potentially exposing them to the killing activity of CART19. Therefore, we sought to investigate the combination of the two novel targeted therapies, ibrutinib and CART19 in MCL. Results: In vitro studies with established MCL cell lines and with a novel cell line (MCL-RL) showed a range of responses to ibrutinib with an IC50 ranging from 10 nM to 10 µM; MCL-RL was the most sensitive cell line evaluated with an IC50 of 10nM, similar to primary MCL. Both ibrutinib-sensitive and ibrutinib-resistant cell lines strongly activated CART19 in an antigen-specific manner as detected by CD107a degranulation, cytokine production and CFSE proliferation assays. Importantly, in vitro assays with MCL cell lines co-cultured with increasing doses of CART19 (E:T= 2:1, 1:1, 0.5:1, 0.25:1) combined with increasing concentrations of ibrutinib (0, 10, 100, 1000 nM) demonstrated strong additive tumor killing (Figure 1). Notably, supra-therapeutic doses of Ibrutinib ( 〉 /=1 uM) impaired cytokine production and T cell proliferation in vitro. In order to test this combination in vivo we established a novel MCL model, injecting i.v. luciferase-positive MCL-RL cells into NSG mice. This resulted in 100% MCL engraftment in liver and spleen, with eventual dissemination into lymph nodes and bone marrow. Treatment with three different doses of CART19 (0.5, 1 and 2 million cells/mouse) led to a dose dependent anti-tumor effect. A similar dose response to CART19 was also observed in the ibrutinib-resistant Jeko-1 cell line. We also treated MCL-RL xenografts with different doses (0, 25 and 125 mg/Kg/day) of ibrutinib, with a median overall survival respectively of 70, 81 and 100 days (p 〈 0.001). Importantly, a direct in vivo comparison of the highest ibrutinib dose (125 mg/kg) and CART19 showed a significantly improved tumor control for mice treated with CART19. However, treatment with either CART19 or ibrutinib as single agents invariably led to late relapse. Therefore we sought to treat MCL-RL xenografts with the combination of CART19 and ibrutinib and compare it to the single agent activity. The combination resulted in significant improvement in tumor control compared to mice treated with the single agents with 80% of mice achieving long-term disease-free survival ( p=0.007 at day 110, representative mice shown in Figure 2A). Intriguingly, we found that mice treated with ibrutinib had higher numbers of circulating CART19 cells (Figure 2B). Conclusions: Combining CART19 with ibrutinib represents a rational way to incorporate two of the most recent therapies in MCL. Our findings pave the way to a two-pronged therapeutic strategy in patients with MCL and other types of B-cell lymphoma. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Ruella: Novartis: Patents & Royalties, Research Funding. Kenderian:Novartis: Patents & Royalties, Research Funding. Maus:Novartis: Consultancy, Patents & Royalties, Research Funding. Milone:Novartis: Patents & Royalties, Research Funding. Lacey:Novartis: Patents & Royalties, Research Funding. Mato:Genentech: Consultancy; Pronai Pharmaceuticals: Research Funding; Celgene Corporation: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; TG Therapeutics: Research Funding; AbbVie: Consultancy, Research Funding; Janssen: Consultancy. Schuster:Genentech: Consultancy; Pharmacyclics: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Hoffman-LaRoche: Research Funding; Janssen: Research Funding; Gilead: Research Funding; Nordic Nanovector: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding. Kalos:Novartis: Patents & Royalties, Research Funding. June:Novartis: Research Funding; University of Pennsylvania: Patents & Royalties: financial interests due to intellectual property and patents in the field of cell and gene therapy. Conflicts of interest are managed in accordance with University of Pennsylvania policy and oversight. Gill:Novartis: Patents & Royalties, Research Funding. Wasik:Janseen and Novartis: Research Funding.

Abstract: Aim A prospective study to determine the safety of the accelerated delivery of rituximab. Methods A pilot study investigating the safety of the accelerated delivery of rituximab was commenced in September 2004. First doses of rituximab were delivered as per prescribing guidelines. Patients without infusion related toxicity were eligible for accelerated rituximab in second or subsequent infusions. In the first 4 patients the infusion was administered at 100mg/hr, increasing to 400mg/hr after 15 minutes in the absence of a reaction. All subsequent patients commenced the infusion at 400mg/hr. All patients received premedication with paracetamol, promethazine and hydrocortisone unless contra-indicated. Patients with a previous grade III/IV infusion related toxicity were excluded. Results 23 patients have been enrolled to date. Data is available for 62 infusions - median 3 infusions per patient (range: 1–6). Median age was 64 years (range: 28–85). 65% of patients were male. Diagnoses included non-Hodgkin’s Lymphoma - 20 patients (Diffuse Large Cell Lymphoma - 8, Follicular Lymphoma - 9, Mantle Cell Lymphoma - 1, Lymphoplasmacytic Lymphoma - 2), Immune Thrombocytopenic Purpura - 2 and Dermatomyositis-1. 44% of patients received single agent rituximab and 56% received it in combination with chemotherapy. The median dose of rituximab was 700mg (range: 600–800mg). There were 2 adverse events with no grade III/IV infusion related toxicity. One patient experienced grade I hypothermia. A second patient experienced grade II fevers and rigors which required interruption of the infusion. The patient was subsequently found to have pneumonia. The infusion was completed without further incident. Excluding data from the latter patient, median infusion time was 1 hour and 55 minutes and 76% of infusions were completed within 2 hours. Conclusion For second or subsequent infusions, the accelerated delivery of rituximab is safe and well tolerated allowing shorter outpatient stays and improving the efficiency of resource utilisation. The study has been extended to include patients with bulky lymphoma and Chronic Lymphocytic Leukaemia.

Abstract: PMBCL is considered to be a distinct entity among diffuse large B-cell lymphoma (DLBCL). The optimal therapy is still matter of debate and the impact of the addition of rituximab to conventional chemotherapy is unknown. The aim of this subgroup analysis of the MInT study was to evaluate the effect of rituximab in PMBCL in comparison to other DLBCL with mediastinal involvement (mDLBCL). Eligible for the MInT study (Lancet Oncol2006; 7: 379–91) were patients aged 18–60 years with DLBCL who had 0–1 risk factors according to age-adjusted International Prognostic Index (IPI), stage II-IV disease, or stage I disease with bulk. Patients were randomly assigned to six cycles CHOP-like chemotherapy regimens with or without rituximab. Consolidating radiotherapy (30–40 Gy) was given to sites of primary bulky disease. Results: Of 824 patients enrolled, 87 had PMBCL and 139 mDLBCL according to nationally centralized hematopathologist review. 44 patients (51%) with PMBCL and 65 patients (47%) with mDLBCL were randomized to the rituximab arm. The subsets were balanced for IPI, but patients with PMBCL were younger (median age 35 vs 43 years); showed more frequently an elevated LDH (63% vs 33%), stage I/II disease (92% vs 65%) and bulky disease (85% vs 60%); and received more often mediastinal radiotherapy (69% vs 37%) compared with mDLBCL. Rituximab increased the rates of complete remission or complete remission unconfirmed (CR/CRu) in both subsets although this was statistically significant only for PMBCL (see Table). This was mainly due to the fact that in both subsets rituximab virtually eliminated progressive disease (PD) under primary treatment, whereas without rituximab, PD tended to be more frequent in PMBCL than in mDLBCL (24% vs 11%, p=0.09). With a median observation time of 37 months (range 0–59), estimated 3-year event-free-survival (EFS) was improved by rituximab for PMBCL (78% vs 52%, p=0.012), mDLBCL (74% vs 59%, p=0.130), and all other DLBCL (n=597, 80% vs 60%, p 〈 0.0001). Rituximab also improved progression-free-survival (PFS) of PMBCL, but not of mDLBCL (Table). This could be explained in part by the favorable outcome of mDLBCL compared to PMBCL in the chemotherapy-only arm (3-year PFS 77% vs 64%, p=0.08). In both subsets, the overall survival (OS) benefit observed with rituximab did not reach statistical significance (Table). Multivariable cox regression models (adjusting for treatment arm; IPI; etoposide use (CHOEP21); bulky disease; histology (PBMCL vs mDLBCL); and the interactions between histology and treatment arm, and histology and IPI, respectively) identified rituximab as a strong prognostic factor and a trend to an interaction between histology and treatment arm for the outcome of a patient. Conclusion: In young patients with PMBCL, rituximab added to 6 cycles of CHOP-like chemotherapy increases response rate, EFS, and PFS to the same extent as in other DLBCL, thereby eliminating the outcome disadvantage of PMBCL observed with CHOP-like chemotherapy alone. PMBCL Rituximab CR/CRu PD 3y-EFS 3y-PFS 3y-OS No 54% (38%–70%) 24% (11%–38%) 52% (35%–66%) 64% (46%–77%) 78% (61%–88%) Yes 80% (68%–92%) 3% (0%–7%) 78% (61%–88%) 88% (70%–95%) 89% (71%–96%) P-value 0.03 0.006 0.012 0.006 0.16 mDLBCL Rituximab CR/Cru PD 3y-EFS 3y-PFS 3y-OS No 67% (55%–78%) 11% (3%–18%) 59% (46%–70%) 77% (64%–86%) 89% (79%–95%) Yes 81% (71%–91%) 2% (0%–5%) 74% (60%–83%) 81% (68%–89%) 92% (79%–97%) P-value 0.1 0.07 0.13 0.71 0.47