ALBERT

Description: Introduction CTL019 is a novel, investigational, chimeric antigen receptor (CAR) immunotherapy whereby autologous T cells are genetically modified with a chimeric antigen receptor to target CD19 on the surface of malignant as well as healthy B cells. The cellular kinetics of CTL019 have been evaluated in several trials for patients with relapsed/refractory CD19+ leukemias, including pediatric acute lymphoblastic leukemia (pALL), adult ALL (aALL), and chronic lymphocytic leukemia (CLL) (Maude 2014, Porter 2015). Methods The cellular kinetic profile of CTL019 was determined in peripheral blood (PB) and bone marrow (BM) through serial measurements using flow cytometry and quantitative real-time polymerase-chain-reaction (qPCR) assay in 3 studies comprised of (i) 55 pALL patients (NCT01626495), (ii) 28 adult CLL patients from a dose selection study (NCT01747486), and (iii) 14 CLL and 6 adult ALL patients (NCT01029366). The flow cytometry assay used a CAR19-specific anti-idiotype antibody to enumerate CTL019 T cells as a % of CD3+ T cell (Porter 2015). Cellular kinetic parameters included: maximal extent of expansion as measured by peak copies of CTL019 DNA and peak % by flow cytometry (Cmax), area under the curve at day 28 (AUC0-28d) describing expansion and persistence in the first month, and time to reach Cmax (Tmax). Parameters were derived by non-compartmental methods. Where estimable, persistence was described by the half-life (T1/2) based on the slope of the terminal phase. Results Following infusion, CTL019, expansion and persistence was evident in the patients who responded to CTL019 as measured by both PK assays across all 3 studies. Table 1 summarizes (arithmetic mean (SD)) the CTL019 kinetic parameters. With complete remission (CR/CRi), CTL019 cells undergo rapid in vivo expansion beyond the original CTL019 dose with maximal expansion at a mean of 11 days in pALL and aALL and approximately 14-18 days in adult CLL as determined by qPCR and flow cytometry (Table 1). In CR/CRi patients the transgene level-profiles in PB reveal a kinetic profile with an initial rapid expansion followed by a slower decay function with some fluctuations of transgene over time resulting in higher AUC0-28d and Cmax, while non-responder (NR) patients tend to have a lower expansion and faster decay (shorter T1/2)of CAR positive T-cells resulting in lower AUC0-28d and Cmax by, leaving the mechanism to be further explored. In pALL, significantly higher AUC0-28d and Cmax were observed in CR/CRi patients compared to NR patients by flow cytometry; however, a wide range of mean AUC0-28d and Cmax was observed in NR patients (n=3) resulting from significant expansion in one NR patient as determined by qPCR. In CLL, the exposure metrics AUC0-28d and Cmax were approximately 12 times higher in CR/CRi patients compared with PRi/NR/PD in NCT01747486; a similar trend was observed in NCT01029366. Similar findings were captured by the flow cytometry based measurements as summarized in Table 1. In pALL and CLL, CR/CRi patients tend to maintain higher levels of CTL019 transgene over longer periods of time (〉6 months) compared to NR patients as demonstrated by the longer T1/2 value. Cellular kinetic parameters were not summarized by response category for aALL due to the small sample size (n=5 CR/CRi; n=1 NR). CTL019 transgene levels ranged from below the limit of quantification (BLQ) to 178,000 copies/ug in aALL patients with CR/CRi and BLQ to 21,900 copies/ug in the NR. CTL019 positive cells were also shown to traffic to BM at 1 month in responders (CR/CRi), irrespective of the disease. Conclusions Overall, significantly higher levels of in vivo proliferation and persistence were observed in patients who successfully responded to CTL019 (i.e. CR/CRi/PR) compared to NRs in both CLL and (adult and pediatric) ALL patients, as captured by both analytical measures, indicating that the kinetics of CTL019 T cells and that proliferation and persistence of CTL019 reasonably predicts response to therapy. These are the first three studies to demonstrate that cellular kinetics may predict responses to CAR based cellular therapy. These results imply that measures to increase proliferation and persistence of CAR T cells may enhance responses in resistant patients. Figure. CTL019 concentration-time profiles for %CD3+/CTL019+ measured by flow cytometry and cellular kinetic parameters for qPCR and flow cytometry for p-ALL and adult CLL Figure. CTL019 concentration-time profiles for %CD3+/CTL019+ measured by flow cytometry and cellular kinetic parameters for qPCR and flow cytometry for p-ALL and adult CLL Disclosures Mueller: Novartis Pharmaceuticals: Employment. Chakraborty:Novartis Pharmaceuticals: Employment, Equity Ownership. Wood:Novartis Pharmaceuticals: Employment, Other: Stock. Awasthi:Novartis Pharmaceuticals: Employment. Quintas-Cardama:Novartis Pharmaceuticals: Employment, Equity Ownership. Han:Novartis Pharmaceuticals: Employment, Equity Ownership. Maude:Novartis: Consultancy. Grupp:Jazz Pharmaceuticals: Consultancy; Pfizer: Consultancy; Novartis: Consultancy, Research Funding. Porter:Novartis: Patents & Royalties, Research Funding; Genentech: Employment. Frey:Novartis: Research Funding; Amgen: Consultancy. Marcucci:Novartis: Research Funding. Levine:GE Healthcare Bio-Sciences: Consultancy; Novartis: Patents & Royalties, Research Funding. Melenhorst:Novartis: Research Funding. June:Celldex: Consultancy, Equity Ownership; Immune Design: Consultancy, Equity Ownership; Pfizer: Honoraria; Novartis: Honoraria, Patents & Royalties: Immunology, Research Funding; University of Pennsylvania: Patents & Royalties; Tmunity: Equity Ownership, Other: Founder, stockholder ; Johnson & Johnson: Research Funding. Lacey:Novartis: Research Funding.

Description: We recently conducted a clinical trial of CD22-directed chimeric antigen receptor (CAR) T cells in children and adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). While we did observe some transient responses, overall outcomes were inferior to another recent trial of CD22 CAR T cells in ALL performed at the NCI (Fry, T.J. et al. Nat Med, 2018). Intriguingly, these trials used a CAR that employed the same antigen-binding and intracellular signaling domains, and differed only in the length of linker connecting the variable regions of the single chain variable fragment (scFv). Based on these clinical observations, we sought to identify how the scFv linker impacts CAR biology and regulates CAR-driven T cell activity. The University of Pennsylvania's CD22 CAR contained a long 20 amino acid scFv linker ("CAR22-L") while the NCI's CAR had a 5 amino acid linker ("CAR22-S"). We began by investigating the impact of linker length on CAR biochemistry. Both CAR22-L and CAR22-S had similar antigen-binding affinities (KD of 1.67nM and 6.05nM, respectively). Chromatography revealed that CAR22-L remained monomeric in solution while CAR22-S formed homodimers. To explore how dimerization influenced surface-membrane biology, we developed GFP-tagged versions of each CAR and performed confocal microscopy on CAR+ T cells. CAR22-L exhibited homogenous surface membrane expression, while CAR22-S appeared to self-aggregate and cluster (Fig. 1a). We investigated the impact of this clustering on receptor signaling and found that CAR22-S demonstrated high levels of signaling molecule activation (i.e. Akt, p70-S6 and STAT3) in the absence of antigen engagement. This is consistent with previous reports establishing that CAR clustering can lead to tonic signaling (Long, A.H. et al. Nat Med, 2015). Importantly, this tonic signaling did not lead to autonomous T cell proliferation. We proceeded to evaluate how clustering and tonic signaling impacted CAR function upon antigen engagement. Microscopic evaluation of CAR T cells combined with CD22+ Nalm6 cells revealed greater actin and microtubule organizing complex polarization (P = 0.02 and 0.01, respectively) in CAR22-S cells, consistent with superior immune synapse formation. This was accompanied by increased phosphorylation of PI3K, MAPK and calcium signaling proteins (Fig. 1b) after CAR engagement. RNA sequencing revealed significantly greater activation of immune response gene programs in CAR22-S cells as compared to CAR22-L after overnight exposure to Nalm6. We next investigated the impact that this enhanced receptor-driven activity had on CAR T cell anti-tumor function. CAR T cells were combined with Nalm6 in vitro and residual Nalm6 was serially quantified, revealing that CAR22-S mediated greater tumor control than CAR22-L, particularly at later time periods (P 〈 0.001). This was associated with greater secretion of IFNg, IL-2 and TNFa (all P 〈 0.001). Finally, we compared anti-tumor efficacy in xenograft models of systemic Nalm6. NOD/SCID/cg-/- mice were engrafted with Nalm6 and received 1x106 CAR T cells 7 days later. CAR22-S demonstrated greater in vivo expansion (P 〈 0.0001) and enhanced control of systemic disease (Fig. 1c,P = 0.017), resulting in prolongation of animal survival (Fig. 1d,P = 0.013). Based on these observations, we have designed a novel, affinity-enhanced CD22 CAR and confirmed that shorter linker length improves anti-tumor activity of this CAR. T cells expressing this CAR are currently undergoing evaluation in a phase I clinical trial (ClinicalTrials.org Identifiers NCT03620058 and NCT02650414). Thus far, 4 children and 2 adults have been infused with manageable toxicity. Early outcomes are promising, with 67% achieving complete remission at day 28, compared to 50% in our original CART22 trials. In summary, by investigating the potential mechanisms for an apparent discrepancy in outcomes between two different clinical trials, we demonstrate that reducing the length of the scFv linker results in significant changes to CAR biochemistry that directly lead to antigen-independent receptor activity. In contrast to previously published data demonstrating that tonic signaling of CD28-costimulated CARs is detrimental to T cell function (Long, A.H. et al. Nat Med, 2015), we found that tonic signaling of 4-1BB-costimulated CARs may be beneficial, possibly by priming T cells for rapid response to antigen. Disclosures Singh: University of Pennsylvania: Patents & Royalties. Frey:Novartis: Research Funding. Engels:Novartis: Employment. Zhao:Novartis: Employment. Peng:Novartis: Employment. Granda:Novartis: Employment. Ramones:Novartis: Employment. Lacey:Novartis: Research Funding; Novartis: Patents & Royalties: Patents related to CAR T cell biomarkers; Tmunity: Research Funding. Young:novartis: Research Funding. Brogdon:Novartis: Employment. Grupp:Roche: Consultancy; GSK: Consultancy; Novartis: Consultancy, Research Funding; Humanigen: Consultancy; CBMG: Consultancy; Novartis: Research Funding; Kite: Research Funding; Servier: Research Funding; Jazz: Other: study steering committees or scientific advisory boards; Adaptimmune: Other: study steering committees or scientific advisory boards; Cure Genetics: Consultancy. June:Novartis: Research Funding; Tmunity: Other: scientific founder, for which he has founders stock but no income, Patents & Royalties. Maude:Novartis: Consultancy; Kite: Consultancy. Gill:Novartis: Research Funding; Tmunity Therapeutics: Research Funding; Carisma Therapeutics: Research Funding; Amphivena: Consultancy; Aro: Consultancy; Intellia: Consultancy; Sensei Bio: Consultancy; Carisma Therapeutics: Equity Ownership. Ruella:AbClon: Membership on an entity's Board of Directors or advisory committees; Nanostring: Consultancy, Speakers Bureau; Novartis: Patents & Royalties: CART for cancer.

Description: Although deferasirox use is established in clinical practice for iron overload, there have been a spate of case reports describing hematologic improvement attributed to use of this agent in myelodysplastic syndrome (MDS) patients (Guariglia et al, Leuk Res, 2011, 35 (5), 566-570). In addition, a post-hoc analysis was conducted assessing hematologic improvement in patients enrolled on the Evaluation of Patients' Iron Chelation with Exjade (EPIC) trial of deferasirox chelation therapy in low or intermediate-1 risk MDS. Erythroid, platelet, and neutrophil responses were observed in 21.5%, 13.0%, and 22.0% of 341 patients after a median of 109, 169, and 226 days, respectively (Gattermann, N et al, Haematologica, 2012, 97 (9), 1364-1371). There has even been a case report of a patient with acute monocytic leukemia who achieved a complete remission after deferasirox therapy (Fukushima et al, Anticancer Res, 2011, 31 (5) 1741-1744). Preclinical data has suggested potential mechanisms for hematologic improvement, including modulation of reactive oxygen species and activating the MAP kinase pathway (Callens et al, J Exp Med, 2010, 37 (4), 731-750), increased labile plasma iron leading to reactive oxygen species induction (Naka K et al, Antiox Redox Signal, 2008, 10 (11) 1883-1894), or inhibition of nuclear factor Kappa B (Messa et al, Haematologica, 95 (8) 1308-1316). Given these intriguing findings, we performed a single-center, investigator-initiated pilot study of deferasirox in MDS International Prognostic Scoring System (IPSS) 1.5 or greater, intolerant of or with lack of response to hypomethylating agents, and acute myeloid leukemia (AML), either relapsed or refractory after treatment with a non-intensive regimen or newly diagnosed and not appropriate candidates for induction chemotherapy. As an inclusion criterion, baseline serum ferritin was 〉 or = to 500 ng/mL. Prior therapy with iron chelating agents within the last 6 months was an exclusion criterion. Current therapy for AML or MDS, including hydroxyurea to control leukocytosis, was prohibited. Thirteen patients consented to the study. There was one screen failure and one patient withdrew from the study after one day. Eleven patients received deferasirox at an initial dose of 10 mg/kg/day which was increased to 20 mg/kg/day if tolerating well. Three of 11 patients (27%) responded. One of the three responding patients achieved red blood cell (RBC) transfusion independence (no RBC transfusions for 6 weeks before death related to infectious complications), one improved bone marrow blasts from 57% to 30% after one month of therapy and the third patient improved bone marrow blasts from 13% to 8% after one month of therapy. The patient who achieved RBC transfusion independence did not achieve any other measures of response. The two patients who responded in the bone marrow did not achieve a concomitant hematologic response. Of the 8 non-responding patients, one patient had stable disease and was on study for one year. One patient withdrew in the setting of neutropenic fever and mild transaminitis that was possibly attributable to deferasirox and was terminated from the study. One patient withdrew from the study due to personal choice and the remaining 5 patients came off study in the setting of complications from progressive disease. Study drug was generally well tolerated. Grade 3 adverse events (AEs) included three patients with elevated creatinine (27%) and 2 patients with diarrhea (18%). One responding patient had a lower gastrointestinal bleed that was possibly attributable to deferasirox and was terminated from the study for this reason. One patient had grade 4 dry mouth immediately after drinking deferasirox slurry that resolved by 30 minutes after ingestion. No other significant AEs occurred that were possibly attributable to deferasirox. In conclusion, deferasirox was generally well tolerated and showed modest activity as a single agent in higher risk MDS or non-proliferative acute myeloid leukemia. Further study of deferasirox in the phase II setting as monotherapy or in combination with other therapies such as hypomethylating agents (HMAs) or HMAs in combination with venetoclax is probably warranted. Disclosures Frey: Novartis: Research Funding. Carroll:Astellas Pharmaceuticals: Research Funding; Incyte: Research Funding; Janssen Pharmaceuticals: Consultancy. Luger:Agios: Honoraria; Ariad: Research Funding; Biosight: Research Funding; Celgene: Research Funding; Cyslacel: Research Funding; Daichi Sankyo: Honoraria; Genetech: Research Funding; Jazz: Honoraria; Kura: Research Funding; Onconova: Research Funding; Pfizer: Honoraria; Seattle Genetics: Research Funding. OffLabel Disclosure: Presentation will discuss the off-label use of Exjade (deferasirox) as therapy for higher risk MDS or AML. Deferasirox on-label use is for iron chelation.

Description: Introduction: Venous thromboembolism (VTE) is a significant adverse event in adults receiving pegaspargase (PEG) for acute lymphoblastic leukemia (ALL). PEG increases VTE risk by depletion of antithrombin III (AT). Heparin requires adequate AT for anticoagulation. Younger adults with T-cell ALL receiving prednisone may be particularly at risk. Retrospective series (most with L-asparaginase) suggest AT supplementation may decrease VTE, however prospective data in adults beyond induction is limited while the optimal dose of AT remains undefined and varies across series. We reviewed adults at our institution who received PEG for ALL to assess the incidence of VTE within our AT supplementation practice. Laboratory and cost data for AT repletion were also analyzed. Methods: Adults who received PEG for ALL between 11/2015 and 7/2018 were retrospectively identified. Institutional recommendations were to supplement AT if serum AT 〈 60% following PEG for at least the first 2 courses (induction/consolidation). AT levels were assessed twice weekly until normalized. AT supplementation following additional cycles was recommended for all patients receiving therapeutic anticoagulation. Pharmacists calculated the AT dose using a repletion factor of 80-120%, rounded to the nearest vial. After VTE, patients received therapeutic enoxaparin throughout all remaining PEG doses, with enoxaparin held only if platelets 〈 50,000/mcL or for procedures. After 3/2018, all patients receiving PEG also received enoxaparin prophylaxis when platelets 〉30,000/mcL. A retrospective analysis was done to assess the incidence of VTE. Secondary endpoints included an assessment of VTE risk factors, ability to achieve therapeutic AT levels with supplementation and to characterize drug therapy costs with AT supplementation. Results: Thirty-one patients (30 newly diagnosed, 1 in relapse) with ALL received ≥ 1 dose of PEG followed by AT supplementation. Seventeen of 31 patients were adolescent/young adults (AYA) and 13/31 had T cell ALL. Additional patient characteristics are summarized in table 1. The incidence of VTE was 19%, with 7 VTEs identified in 6 patients. Two patients developed CNS thrombosis (1 fatal), 1 had a pulmonary embolism, and the remainder were upper extremity VTE. Six of 7 VTE occurred during the first two courses at a mean of 66 days (range 6-225) following the first PEG dose. Patients with VTE had a median platelet count of 118/mcL (range 34-377) and a mean AT nadir of 53% (36-98) within 72 hours of VTE. Two of 7 events occurred despite enoxaparin prophylaxis. Five of 6 (83%) patients with VTE had T-ALL; which was more common in the VTE vs. no-VTE group (p = 0.01). The incidence of VTE within the T-ALL group was 38%. Patients with VTE were all AYA and were younger than those without VTE (median 31 vs. 42 years, p = 0.06). Patients with VTE received a higher mean PEG dose than patients without VTE (4589 vs. 3504 units, p 〈 0.0001), reflective of the more aggressive dosing in the AYA regimen. Six of 7 VTEs occurred during a course containing prednisone (p = 0.08 vs. dexamethasone). AT nadirs during cycles with VTE were similar to cycles without VTE. No clinically significant bleeding occurred. Characteristics of patients with VTE are summarized in table 2. Overall the mean time to AT nadir was 11 days. Therapeutic AT (〉 60%) following supplementation occurred 56% of the time. Most AT doses (89%) were calculated with a correction factor of 80-89%. The probability of obtaining a therapeutic AT increased when a higher repletion factor (〉 90%) was used (76% vs. 52%, p = 0.06). Patients received a mean of 1.9 (0-6) doses of AT per PEG dose, and a mean of 5.9 (1-21) AT doses throughout treatment. The mean AT supplementation cost per PEG dose was $11,663 with 186 doses administered ($3.22/unit). Conclusions: VTE occurred in 19% of patients receiving AT supplementation following PEG, with 2/7 events involving the CNS. The risk of VTE was greatest in younger adults with T-ALL receiving concurrent prednisone and higher doses of PEG. AT levels were low at the time of VTE in most patients, however nadirs were similar compared to courses not complicated by VTE. Routine or augmented VTE prophylaxis and a higher AT repletion goal (〉 90%) may further limit VTE risk but given the cost and patient inconvenience, prospective evaluation is needed to confirm the benefit. Disclosures Frey: Servier Consultancy: Consultancy; Novartis: Consultancy. Perl:Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy; Actinium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Arog: Consultancy; Astellas: Consultancy; NewLink Genetics: Membership on an entity's Board of Directors or advisory committees. Porter:Genentech: Other: Spouse employment; Novartis: Other: Advisory board, Patents & Royalties, Research Funding; Kite Pharma: Other: Advisory board.

Description: Introduction: Chimeric antigen receptor T-cell therapy (CAR-T) is a revolutionary adoptive immunotherapy approach in lymphoma; however, there are substantial costs associated with CAR-T therapy. The current practice of admission for tisa-cel infusion and subsequent monitoring may contribute to these costs. Generally, our institution administers tisa-cel in the outpatient setting (Schuster NEJM 2017), and we now report our clinical approach and analyze the frequency of hospitalization post outpatient tisa-cel infusion with in the first 30 days of infusion. Patients and Methods: We conducted a single institution, retrospective study investigating hospitalization after CAR-T of adult lymphoma patients treated with commercial tisa-cel at the University of Pennsylvania between 6/2018 and 7/2019. Data collected included number and timing of hospitalizations, symptoms leading to hospitalization, diagnosis during hospitalization, and length of stay. Patients were eligible for inclusion if they had at least 30 days of follow-up after tisa-cel or hospitalization within the first 30 days after tisa-cel. Patients were followed for hospitalization events until progression of lymphoma. Admissions for elective surgical procedures were not included in hospitalization count. Patients received lymphodepleting therapy as an outpatient, followed by evaluation in clinic and outpatient infusion of tisa-cel. Indications for hospitalization at our institution included bulky disease, suboptimal organ function at time of tisa-cel infusion, or progressive lymphoma symptoms requiring inpatient management. After infusion, patients returned for follow-up on day 2 and day 4, then weekly starting day 8 through day 30 for physical examination, labs, and assessment for cytokine release syndrome (CRS) and neurotoxicity. Patients were instructed to contact our clinic with fever 〉 100.4F, any change in mental status, or for malaise. Patients were also required to stay within 1 hour driving distance of our clinic and have identified a caregiver who will remain with them for the first 28 days. Results: 30 patients with relapsed/refractory non-Hodgkin lymphoma who received commercial tisa-cel were identified; 28 (93%) patients received outpatient tisa-cel; two pts were admitted at the time of T-cell infusion due to progressive lymphoma symptoms requiring urgent management. The length of stay for the two patients who received inpatient tisa-cel was 17.5 days (17-18). Nine of 28 patients were admitted after tisa-cel infusion a median of 5 days after tisa-cel infusion (range: day +1 to +7). No patient required a second admission within 30 days. In most instances, 8/9 (89%) patients were referred for fever (fever range: 99.6F-102.0F) and one patient was referred for altered mental status. Of those hospitalized with fever, 5/8 (63%) patients had CRS and 3/8 (37%) patients had an infection. The patient with altered mental status was diagnosed with grade 3 neurotoxicity. One of the admitted patients died during hospitalization; however, this was due to progression of lymphoma after initial admission for an infection. There were no deaths due to tisa-cel related toxicity. Conclusion: Our experience suggests that treatment with tisa-cel in the outpatient setting is safe and feasible with close supervision and adequate institutional experience. After infusion, most admissions within the first 30 days were triggered by fever and the etiology of fever was either CRS or infection. Admission diagnoses matched prior experience with tisa-cel as previously reported. Disclosures Dwivedy Nasta: Millenium/Takeda: Research Funding; Aileron: Research Funding; Pharmacyclics: Research Funding; Rafael: Research Funding; Celgene: Honoraria; Merck: Membership on an entity's Board of Directors or advisory committees; ATARA: Research Funding; Debiopharm: Research Funding; Roche: Research Funding; 47 (Forty Seven): Research Funding. Hughes:Acerta Pharna/HOPA: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genzyme: Membership on an entity's Board of Directors or advisory committees. Chong:Novartis: Consultancy; Tessa: Consultancy; Merck: Research Funding. Svoboda:AstraZeneca: Consultancy; Celgene: Research Funding; Incyte: Research Funding; Pharmacyclics: Consultancy, Research Funding; Kyowa: Consultancy; Merck: Research Funding; BMS: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding. Landsburg:Celgene: Membership on an entity's Board of Directors or advisory committees; Curis, INC: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Curis, INC: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Speakers Bureau; Seattle Genetics: Speakers Bureau; Takeda: Research Funding; Takeda: Research Funding; Triphase: Research Funding; Triphase: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Barta:Celgene: Research Funding; Mundipharma: Honoraria; Celgene: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Takeda: Research Funding; Bayer: Consultancy, Research Funding; Seattle Genetics: Honoraria, Research Funding. Gerson:Seattle Genetics: Consultancy; Pharmacyclics: Consultancy; Abbvie: Consultancy. Ruella:Nanostring: Consultancy, Speakers Bureau; Novartis: Patents & Royalties: CART for cancer; AbClon: Membership on an entity's Board of Directors or advisory committees. Frey:Novartis: Research Funding. Schuster:Novartis: Other: a patent (with royalties paid to Novartis) on combination therapies of CAR and PD-1 inhibitors.; Novartis, Nordic Nanovector, and Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis, Celgene, Genentech, Merck, Pharmacyclics, Acerta, and Gilead: Other: Grants, Research Funding; Nordic Nanovector, Pfizer, AstraZeneca, Loxo Oncology, Acerta, and Celgene: Honoraria. Porter:Wiley and Sons: Honoraria; Immunovative: Membership on an entity's Board of Directors or advisory committees; American Board of Internal Medicine: Membership on an entity's Board of Directors or advisory committees; Genentech: Employment; 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; Novartis: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees.

Description: BACKGROUND: Conventional treatment options for patients with relapsed hematologic malignancies are both limited and highly toxic driving the pursuit of more tumor specific and less toxic therapies. RNA targeted oligonucleotides are potentially powerful drugs with the ability to silence genes required for malignant hematopoietic cell growth at the post transcriptional level. Studies from our laboratory have validated the c-myb proto-oncogene, which regulates important hematopoietic cell functions and is overexpressed in many hematologic malignancies, as a target for this technology. A prior Phase I trial using a 24 nucleotide phosphorothioated antisense oligodeoxynucleotide targeted to c-Myb mRNA (C-MYB AS ODN) did not identify a maximum tolerated dose (MTD) of the drug. Here we report initial results of a follow up Phase I dose escalation trial using C-MYB AS ODN at higher dose levels than previously studied in subjects with refractory hematologic malignancies. METHODS: C-MYB AS ODN is administered as a 7 day continuous infusion. 5 dose levels ranging from 3mg/kg/day to 12mg/kg/day are planned. Subjects are enrolled using an accelerated dose escalation scheme in which one subject is enrolled on each dose level (DL) with plans to revert to the standard 3+3 design in the event of significant attributable toxcity. C-MYB AS ODN concentrations are measured in peripheral blood (PB) and in mononuclear cells (MNC) by slot blotting at baseline, days 3 and 7 of infusion and two weeks after cessation of infusion. C-myb expression is assessed at these timepoints though QRT-PCR for c-myb RNA. Disease specific assessments of response are measured at predefined timepoints after therapy. RESULTS: 6 subjects, all with refractory acute myelogenous leukemia (AML) have enrolled to date. Escalation through the first 3 DLs occurred without any toxicities. At DL4 (10mg/kg/day) abnormalities have been noted in coagulation assays. The first subject enrolled on DL 4 developed a grade 3 prolongation of the activated partial thromboplastin time (PTT) attributable to drug which returned to normal within 48 hours of drug cessation. Factor levels, DIC parameters and reptilase time were normal. The PTT abnormality was consistent with a “lupus like” inhibitor effect (DRVVT was abnormal and the PTT corrected with the addition of phospholipid in two independent tests.) The 2nd subject treated at DL 4 developed a milder but similar PTT prolongation. The 3rd subject enrolled on DL 4 had a normal PTT throughout therapy. No subjects developed bleeding complications. Plasma and intracellular drug concentrations were dose related (320–640pg/l and 2–80 ng/5×10e6 cells respectively). Peak drug concentrations were found on Days 3–7. By 14 days after infusion, most ODN was cleared from plasma, but remained measurable in MNC at concentrations 30–50% of the maximum value detected. QRT-PCR for c-myb mRNA was performed in 3 subjects. Subject 1’s (DL 1) c-myb mRNA levels gradually decreased from baseline during infusion and nadired two weeks after cessation of infusion. Subjects 3 (DL 3) & 5 (DL 4) had a decrease in c-myb mRNA levels midway through infusion but c-myb RNA levels increased back to baseline by cessation of infusion. To date no subject has had a clinically important response to therapy. Accrual continues for DL 5. CONCLUSIONS: C-MYB AS ODN is detectable in plasma and MNCs of subjects during continuous drug infusion with a steady state reached by day 3 of infusion. Plasma drug levels were markedly reduced 14 days after cessation of infusion but MNC drug levels remained elevated. C-MYB AS ODN at DL 4 (10mg/kg/day) is associated with a PTT prolongation consistent with a “lupus inhibitor” like effect. While encouraging biological activity was identified optimal dose and delivery remain to be established before clinically significant effects can be reasonably expected.

Description: CTLO19 cells are CAR-modified T cells which recognize CD19 and produce high durable remission rates for pts with relapsed or refractory acute lymphoblastic leukemia (ALL). Cytokine Release Syndrome (CRS) has emerged as the major treatment related effect from CTL019, with symptoms that include high fevers and malaise but can progress to capillary leak, hypoxia and hypotension. CRS occurs hours to days after CTL019 infusion and correlates with rapid in vivo CTL019 expansion and marked elevation of serum IL6. In most cases, CRS is self-limited or rapidly reversed with anti-cytokine directed therapies. Here we report 3 cases of refractory CRS in adult pts with ALL. Our experience offers insight into clinical and investigational parameters describing this syndrome; highlights the variance of CRS across disease types and illustrates complexities of CRS management during concurrent infectious illness. As of 7/1/14, 97 pts (30 pediatric ALL, 12 adult ALL, 41 CLL, 14 NHL) have been treated with CTLO19. To capture clinical manifestations of CRS across protocols, we developed a novel CRS grading scale which will be described. Severe CRS (Gr 3-5) occurred in 27 (64%) of ALL pts and only 16 (29%) of CLL/NHL pts (p=0.001). 12 adults with ALL received CTL019; 8/9 evaluable pts achieved CR (MRD negative) at 1 month and 1 pt with extramedullary disease had marked reduction of PET avid disease which is maintained at 1 yr. Severe CRS occurred in 11 of 12 adult ALL pts. CRS was self-limited in 2 pts, rapidly reversed with anti-IL6 directed therapy in 6 pts and was refractory to therapy, contributing to death in 3 pts who were not evaluable for disease response. No baseline attributes differentiate these 3 pts from the 9 adult ALL pts with manageable Gr1-4 CRS. We have shown however that ALL disease burden correlates with CRS severity (in press) and all 3 pts had significant disease burden at baseline. All received lymphodepleting chemotherapy with cyclophosphamide 300 mg/m2 q12h x 6 followed by infusion of CTLO19 cells. These 3 pts each received 6.50E+06, 6.70E+06 and 8.45E+06 CTLO19 cells/kg compared to median CTL019 dose of 3.62E+06 in the 9 adult ALL pts with manageable CRS. Pt 21413-03 developed CRS 12 hrs after infusion and tested positive for influenza B on D3. Despite broad spectrum antimicrobials (including oseltamivir) and anticytokine directed therapy with tocilizumab (4mg/kg x 2) and steroids, he died with refractory hypotension on D5. Pt 21413-06 had extensive disease after 2 prior allogeneic SCTs and developed CRS within 12 hrs of infusion. In addition to broad spectrum antibiotics, she received tocilizumab 8mg/kg (D 3, 6 and 12); intermittent high dose steroids (D 4-15) and etanercept (D14). She died D15 with hypotension, hypoxic respiratory failure and concurrent MDR pseudomonas sepsis and pneumonia. Pt 21413-11 developed CRS within 24 hrs of infusion. He received tocilizumab 8mg/kg (D3&4); siltuximab (D5&15) and intermittent high dose steroids (D 4-15). After an initial response, he developed recurrent fever, pulmonary infiltrates and blood cultures positive for stenotrophomonas. He died D15 with refractory hypoxia and hypotension. All 3 pts’ clinical CRS correlated with marked in vivo CTL019 expansion and progressive serum cytokine elevations (data to be shown). CONCLUSIONS: CRS is the major toxicity of CTL019 therapy and its clinical course varies depending on disease type (more frequent and severe in ALL) and disease burden (in ALL). The 3 refractory CRS cases described here (of 97 total pts treated) have all occurred in adult ALL pts with significant disease burden who received relatively high doses of CTL019 cells. In addition, all 3 had significant infectious complications which potentially fueled underlying CRS and/or were made more virulent due to impairment of immunity with administration of anti-cytokine directed therapies. Future protocol modifications will be made goal of limiting severity of CRS while maintaining high durable remission rates. Further exploration is planned to better correlate timing and choice of anticytokine directed therapy in relation to clinical and investigation parameters of CRS. Disclosures Frey: Novartis: Research Funding. Off Label Use: USe of CART19 cells to treat CLL. Levine:Novartis: Patents & Royalties, Research Funding. Lacey:Novartis: Research Funding. Grupp:Novartis: Consultancy, Research Funding. Schuster:Novartis: Research Funding. Hwang:NVS: Research Funding. Leung:Novartis: Employment. Shen:Novartis: Employment. Ericson:Novartis: Employment. Melenhorst:Novartis: Research Funding. June:Novartis: Patents & Royalties, Research Funding. Porter:Novartis: Patents & Royalties, Research Funding.

Description: BACKGROUND: Effective and well tolerated treatment options for patients with relapsed acute myelogenous leukemia (AML) are limited. Birinapant is a small molecule, peptidomimetic of second mitochondrial-derived activator of caspases (SMAC) that selectively targets Inhibitor of Apotosis proteins (IAPs) resulting in tumor cell apoptosis and inactivation of NF-kB. SMAC mimetics represent a novel class of anti-tumor agents and birinapant has been explored as a single agent and in combination with chemotherapy in trials in solid tumors. Based on pre-clinical response observed in a mouse model with AML, we developed an investigator initiated Phase I clinical trial using single agent birinapant in pts with relapsed AML and high risk myelodysplastic syndrome (MDS). METHODS: Eligible pts were 〉18 years old with non-M3 relapsed or refractory AML or high risk MDS refractory to a hypomethylating agent. A standard 3+3 dose escalation was planned using single agent birinapant at increasing dose levels and frequency. Subjects who did not complete at least one cycle of therapy (4 wks) or experience a dose limiting toxicity (DLT) were replaced. The primary endpoint was safety and determination a maximum tolerated dose (MTD). Secondary endpoints included pharmacokinetic (PK) and pharmacodynamics (PD) analysis as well as disease response. RESULTS: From 12/2011 to 05/2014, 20 subjects were enrolled at the Hospital of the University of Pennsylvania and received at least one dose of study drug, 1 had MDS, 19 had AML (9 with antecedent MDS). The median age was 75 (range 36 to 80). The median number of prior treatments was 2 (range 1 to 5) and 11 patients required hydroxyurea during study treatment. No other concurrent chemotherapy was permitted. Several dose levels were tested varying the dose (17mg/m2, 22mg/m2 and 26mg/m2) and frequency (weekly, twice weekly (BIW) and 3 times weekly (TIW)) for 3 out of 4 wk cycles. Evaluable subjects have stayed on study drug for