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BACKGROUND Belantamab mafodotin (belamaf) has demonstrated clinically meaningful antimyeloma activity in patients with heavily pretreated multiple myeloma. However, the drug is highly active against dividing cells, which contributes to off-target adverse events, particularly ocular toxicity. Investigators or providers routinely use changes in best corrected visual acuity (BCVA) and corneal examination findings to determine Keratopathy Visual Acuity (KVA) grade to inform belamaf dose modification. We sought to model and translate the complexity of the ophthalmologic examination using the KVA scale into a mobile application that is easily applicable to patients presenting with ocular toxicities. OBJECTIVE We aimed to develop a semiautomated mobile app to facilitate the grading of ocular events in clinical trials involving belamaf. METHODS The paper process was semiautomated by creating a library of finite-state automaton (FSA) models to represent all permutations of KVA grade changes between baseline and current BCVA readings. The transition states in the FSA models operated independently of eye measurement units (eg, Snellen, logMAR, decimal) and provided a uniform approach to determining KVA grade changes. Together with the FSA, the complex decision tree for determining the grade change based on corneal examination findings was converted into logical statements that provide accurate and efficient computation of the overall KVA grade. First, a web-based user interface, conforming to clinical practice settings, was developed to simplify the input of key criteria for overall KVA grading. Subsequently, a mobile app was developed that included additional guided steps to assist in clinical decision-making. RESULTS The app underwent a robust Good Clinical Practice validation process in alignment with GSK standard operating procedures, and the outcomes were reviewed by key stakeholders, our medical lead for belamaf, and the systems integration team. The time to compute a patient’s overall KVA grade using the Belamaf Eye Exam (BEE) app was reduced from a 20- to 30-minute process to less than 1 to 2 minutes using our semiautomated KVA computational framework. The BEE app was well received, with most investigators surveyed selecting “satisfied” or “highly satisfied” for its accuracy and time efficiency. Based on current US Food and Drug Administration and EU standards, the BEE app is considered a nondevice clinical decision support software. CONCLUSIONS We conclude that our semiautomated approach provides for an accurate, simplified method of assessment of patients’ corneal status that reduces the number of potential errors and more quickly delivers information critical for potential belamaf dose modifications related to ocular changes. The app is currently available on the Apple iOS and Android platforms for use by investigators of the DREAMM clinical trials. Moreover, this mobile app could extend to the clinic as a tool to support healthcare providers in making informed belamaf treatment decisions for their patients.

ONC201, founding member of the imipridone class of small molecules, is currently being evaluated in advancer cancer clinical trials. We explored single agent and combinatorial efficacy of ONC201 in preclinical models of hematological malignancies. ONC201 demonstrated (GI50 1-8 µM) dose- and time-dependent efficacy in acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), Burkitt's lymphoma, anaplastic large cell lymphoma (ALCL), cutaneous T-cell lymphoma (CTCL), Hodgkin's lymphoma (nodular sclerosis) and multiple myeloma (MM) cell lines including cells resistant to standard of care (dexamethasone in MM) and primary samples. ONC201 induced caspase-dependent apoptosis that involved activation of the integrated stress response (ATF4/CHOP) pathway, inhibition of Akt phosphorylation, Foxo3a activation, downregulation of cyclin D1, IAP and Bcl-2 family members. ONC201 synergistically reduced cell viability in combination with cytarabine and 5-azacytidine in AML cells. ONC201 combined with cytarabine in a Burkitt's lymphoma xenograft model induced tumor growth inhibition that was superior to either agent alone. ONC201 synergistically combined with bortezomib in MM, MCL and ALCL cells and with ixazomib or dexamethasone in MM cells. ONC201 combined with bortezomib in a Burkitt's lymphoma xenograft model reduced tumor cell density and improved CHOP induction compared to either agent alone. These results serve as a rationale for ONC201 single-agent trials in relapsed/refractory acute leukemia, non-Hodgkin's lymphoma, MM and combination trial with dexamethasone in MM, provide pharmacodynamic biomarkers and identify further synergistic combinatorial regimens that can be explored in the clinic.

Blood stream infections (BSI) caused by enteric organisms are associated with a particularly high mortality rate in allogeneic hematopoietic cell transplantation (alloHCT) recipients. We conducted a retrospective multicenter study aiming to analyze the risk factors associated with antibiotic resistance and impact of BSI on transplantation-related mortality (TRM) in children after alloHCT. During the study period from 2004 to 2014, 395 children (mean age, 9.4 years) with at least 1 BSI were included. The incidences of resistant gram-negative rods were 20.7% to piperacillin-tazobactam, 10.9% to cefepime, 21% to ceftazidime, 11.4% to levofloxacin, and 8.16% to meropenem. Thirty-eight percent of Enterococcus spp. isolates were resistant to vancomycin. More than 1 episode of BSI was associated with significant increase in the risk of resistance to piperacillin-tazobactam, cefepime, and vancomycin. On multivariate analysis of risk factors for TRM, achievement of neutrophil engraftment by day 30 was associated with lower TRM (P = .002). However, infection with an antibiotic-resistant organism was not associated with TRM. Development of enteric bacterial BSI after the onset of acute gastrointestinal graft-versus-host disease (GVHD) was the strongest predictor of TRM (hazard ratio, 4.786; 95% confidence interval, 2.833 to 8.087; P .001). In patients with acute gastrointestinal GVHD who subsequently developed enteric bacterial BSI, the incidence of 1-year TRM was 33.4% (SE = 7%), compared with 15.3% (SE = 2%) for those without acute gastrointestinal GVHD (P = .004). Primary prevention of a first episode of BSI is arguably the most important intervention to decrease antibiotic resistance. It is also imperative that we develop strategies to maintain gastrointestinal health, especially in patients with gastrointestinal GVHD, in an effort to prevent subsequent enteric bacterial BSI and improve survival.

Introduction: Belantamab mafodotin (belamaf; GSK2857916) is a B-cell maturation antigen (BCMA)-targeting antibody-drug conjugate. In the pivotal Phase II DREAMM-2 study, single-agent belamaf demonstrated deep and durable responses and a manageable safety profile in patients refractory and/or intolerant to ≥3 lines of therapy, including an anti-CD38 monoclonal antibody such as daratumumab (Lonial et al. Lancet Oncol 2020). Responses were sustained at 13 months of follow-up with belamaf (2.5 mg/kg intravenously [IV] every 3 weeks [Q3W]); overall response rate (ORR) was 32% and median duration of response (DoR) was 11.0 months (Lonial et al. ASCO 2020 Poster 436). Triple combination regimens, such as daratumumab plus bortezomib and dexamethasone (D-Vd), are considered a standard of care for patients with RRMM and have demonstrated superior antimyeloma activity to monotherapy and dual combination regimens, such as bortezomib and dexamethasone. Preclinical data suggest synergistic antimyeloma activity of belamaf and bortezomib (a proteasome inhibitor), and initial results from the ongoing Phase I/II DREAMM-6 study of B-Vd indicate an acceptable safety profile for the combination (Nooka et al. ASCO 2020 Oral 8502). The DREAMM-7 study (NCT04246047) will evaluate the efficacy and safety of B-Vd compared with D-Vd in patients with RRMM. Methods: DREAMM-7 is an ongoing, randomized, open-label, global, multicenter, Phase III, two-arm study in patients with measurable RRMM who had received ≥1 prior therapy with documented disease progression during or after their most recent therapy. Patients aged ≥18 years with Eastern Cooperative Oncology Group Performance Status 0-2, adequate organ system function, and who provide informed consent will be eligible. Patients intolerant/refractory to daratumumab or bortezomib, or with prior exposure to anti-BCMA therapy, will be excluded. Patients will be stratified by the Revised International Staging System, prior exposure to bortezomib, and number of prior lines of therapy. Approximately 478 patients will be randomized (1:1) to Arm A (B-Vd) or Arm B (D-Vd). In Arm A, patients will receive belamaf 2.5 mg/kg (IV) Q3W on Day 1 of each cycle; bortezomib 1.3 mg/m2 (subcutaneously) on Days 1, 4, 8, and 11 of Cycles 1-8 (21-day cycles); and dexamethasone 20 mg (IV or orally) on the day of, and the day after, bortezomib treatment. In Arm B, patients will receive daratumumab 16 mg/kg (IV) in 21-day cycles: Cycles 1-3 Q1W, Cycles 4-8 Q3W, and from Cycle 9 onwards Q4W; dexamethasone and bortezomib schedules will be the same as in Arm A. Treatment will continue in both arms until disease progression, death, unacceptable toxicity, withdrawal of consent, or study end. The primary endpoint is progression-free survival (PFS; time from randomization to the earliest date of documented disease progression or death [any cause]). The key secondary endpoint is minimal residual disease negativity rate, as assessed by next-generation sequencing. Additional secondary endpoints include complete response rate, ORR, DoR, PFS2 (PFS after initiation of new anticancer therapy), overall survival, and endpoints related to pharmacokinetics, antidrug antibodies, safety, and health-related quality of life. As of August 2020, the study is enrolling. Funding: GSK (Study 207503); drug linker technology licensed from Seattle Genetics; mAb produced using POTELLIGENT Technology licensed from BioWa. Disclosures Rifkin: McKesson: Current equity holder in publicly-traded company, Ended employment in the past 24 months, Other: Stock ownership; Takeda, Amgen, Celgene, BMS, Mylan, Coherus BioSciences, Fresenius: Consultancy; AbbVie: Other: Investigator in AbbVie sponsored clinical trials; Takeda, Amgen, BMS (Celgene): Membership on an entity's Board of Directors or advisory committees. Boyd:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Di Raimondo:Amgen: Consultancy, Honoraria; GILEAD, Incyte: Research Funding; Amgen, Takeda, Novartis: Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Dimopoulos:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Weisel:Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Adaptive: Consultancy, Honoraria; GlaxoSmithKline: Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Arnulf:BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria. Hajek:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Pharma MAR: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Spencer:AbbVie, Celgene, Haemalogix, Janssen, Sanofi, SecuraBio, Specialised Therapeutics Australia, Servier and Takeda: Consultancy; Amgen, Celgene, Haemalogix, Janssen, Servier and Takeda: Research Funding; AbbVie, Amgen, Celgene, Haemalogix, Janssen, Sanofi, SecuraBio, Specialised Therapeutics Australia, Servier and Takeda: Honoraria; Celgene, Janssen and Takeda: Speakers Bureau. Davis:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Riccio:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Kim:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Wilkes:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Rutledge:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Talekar:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Kremer:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Gupta:Novartis: Current equity holder in publicly-traded company; GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Mateos:Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; PharmaMar-Zeltia: Consultancy; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Honoraria; GlaxoSmithKline: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: 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.

Introduction: Single-agent belamaf (GSK2857916), a B-cell maturation antigen-targeting antibody-drug conjugate, demonstrated deep and durable responses with a manageable safety profile in patients with heavily pretreated RRMM (median 7 lines of prior therapy) refractory to an immunomodulatory agent (IMiD), a proteasome inhibitor (PI), and refractory and/or intolerant to an anti-CD38 monoclonal antibody in the pivotal Phase II DREAMM-2 study (NCT03525678). At 13-month follow-up, the overall response rate (ORR) was 32% and the median duration of response (DoR) was 11.0 months in the belamaf 2.5 mg/kg arm (Lonial. ASCO 2020 Poster 436). The multimodal mechanism of action, efficacy and safety profile of belamaf, as well as preclinical data suggest possible synergy with standard of care agents and a potential benefit in combination with IMiDs and PIs. DREAMM-6 (NCT03544281) is an ongoing Phase I/II, two-part study of belamaf in combination with lenalidomide/dexamethasone (Arm A) or BorDex (Arm B) in patients with RRMM who had received ≥1 prior therapy (bortezomib-refractory patients were not excluded); preliminary results from Arm B have been reported (Nooka. ASCO 2020 Oral 8502). Methods: Part 1 (dose escalation) and Part 2 (dose expansion) of Arm B in DREAMM-6 evaluated belamaf (2.5 and 3.4 mg/kg intravenously (IV) every 3 weeks [Q3W]) administered as SINGLE (Day 1) or SPLIT dose (divided equally on Days 1 and 8) plus BorDex (Bor 1.3 mg/m2 [subcutaneously] and Dex 20 mg [IV or orally]). Combination treatment continued for up to 8 cycles, with single-agent belamaf maintenance therapy thereafter. Primary objectives were safety, tolerability, and efficacy (ORR [≥ partial response, PR] per investigator-assessed best confirmed response). We report safety and efficacy results from the 2.5 mg/kg SINGLE dose cohort from Arm B. Results: As of March 30, 2020, 18 patients had received belamaf 2.5 mg/kg SINGLE + BorDex in Parts 1 and 2 of Arm B. The median age was 67 years, 61% were male, and 33% had high-risk cytogenetics; patients had received a median of 3 (range, 1-11) prior lines of therapy. All 18 patients had treatment-related adverse events (AEs), of whom 16 (89%) had Grade 3/4 events (see Table). Treatment-related serious AEs occurred in 5 (28%) patients. There were no Grade 5 AEs of interest. Thirteen (72%) patients had dose reductions (8/13 belamaf) and all patients had dose delays (16/18 belamaf) to manage AEs. Five (28%) patients discontinued a study treatment due to AEs: 4 bortezomib, 2 dexamethasone, no patients discontinued belamaf. Of the AEs of interest, thrombocytopenia occurred in 12 patients (67%; maximum Grade 4 in 8 patients and Grade 3 in 3 patients) and led to dose reduction in 6 (33%) patients, dose delay in 7 (39%) patients, and no discontinuations. Three (17%) patients had Grade 2 infusion-related reactions (with no dose modifications or discontinuations). Changes in the corneal epithelium (keratopathy/microcyst-like epithelial changes [MECs], an eye exam finding with or without symptoms), an anticipated AE associated with monomethyl auristatin F, the payload in belamaf, occurred in all 18 patients (maximum Grade 3 in 10 patients, Grade 2 in 7 patients, and Grade 1 in 1 patient), and led to dose reduction in 7 (39%) patients, dose delay in 15 (83%) patients, with no discontinuations. Response was evaluable in all patients; ORR was 78% (95% CI 52.4-93.6), with very good partial response (VGPR) in 9 (50%) and PR in 5 (28%) patients. One (6%) patient had minimal response, and 3 (17%) patients had stable disease. Clinical benefit rate was 83% (95% CI 58.6-96.4). After a median of 18.2 weeks (range 6.0-46.4 weeks) on treatment, median DoR was not reached. Conclusions: The combination of belamaf 2.5 mg/kg Q3W with standard-of care BorDex demonstrated an acceptable safety profile in patients with RRMM who had received a median of 3 prior lines of therapy, with AEs as expected, and no new safety signals to date. Corneal events were common but manageable with belamaf dose modifications. At interim follow-up, best response data indicate a high ORR of 78%, VGPR of 50%, and clinical benefit rate of 83%. Final data for the 2.5 mg/kg SINGLE + BorDex cohort will be reported at the congress. Funding: GSK (Study 207497); drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Disclosures Popat: AbbVie: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Nooka:Karyopharm Therapeutics, Adaptive technologies: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria; Spectrum Pharmaceuticals: Consultancy; Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria; Adaptive Technologies: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria, Other: Personal Fees: Travel/accomodations/expenses, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding. Stockerl-Goldstein:Celgene: Consultancy; Abbott Laboratories: Current equity holder in publicly-traded company; Abbvie: Current equity holder in publicly-traded company; GSK: Research Funding; Takeda: Research Funding; BiolineRx: Research Funding; Janssen: Research Funding; Cellerant: Other: Other relationship. Abonour:Takeda: Consultancy; Janssen: Honoraria, Research Funding; Celgene: Consultancy; BMS: Consultancy, Research Funding. Khot:Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Other: Speaker fees; Novartis: Other: Travel grant. Lee:Janssen: Consultancy; Amgen: Consultancy; Celgene/BMS: Consultancy. Augustson:Roche: Other: Support of parent study and funding of editorial support. Spencer:AbbVie, Amgen, Celgene, Haemalogix, Janssen, Sanofi, SecuraBio, Specialised Therapeutics Australia, Servier and Takeda: Honoraria; Amgen, Celgene, Haemalogix, Janssen, Servier and Takeda: Research Funding; AbbVie, Celgene, Haemalogix, Janssen, Sanofi, SecuraBio, Specialised Therapeutics Australia, Servier and Takeda: Consultancy; Celgene, Janssen and Takeda: Speakers Bureau. Mateos:Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Honoraria; PharmaMar-Zeltia: Consultancy; Abbvie/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: 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. Chopra:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Rogers:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Smith:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Davidge:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Montes de Oca:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Ferron-Brady:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Yeakey:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Talekar:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Kremer:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company. Gupta:GlaxoSmithKline: Current Employment, Current equity holder in publicly-traded company; Novartis: Current equity holder in publicly-traded company. Quach:Sanofi: Consultancy, Research Funding; Janssen Cilag: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria, Research Funding; Glaxo Kline Smith: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding.

8502 Background: Belantamab mafodotin, a B-cell maturation antigen targeting immunoconjugate, demonstrated clinically meaningful, single-agent activity in patients with heavily pre-treated RRMM refractory to an immunomodulatory agent, a proteasome inhibitor, and refractory and/or intolerant to an anti-CD38 monoclonal antibody (DREAMM-2, NCT03525678, Lancet Oncol.2020). The multimodal mechanism of action and manageable safety profile make belantamab mafodotin a promising candidate for use in different RRMM combination regimens. Methods: DREAMM-6 (NCT03544281) is an ongoing, two-part, two-arm, study evaluating the safety, tolerability, and clinical activity of belantamab mafodotin in combination with bortezomib/dexamethasone (BorDex) and lenalidomide/dexamethasone in patients previously treated with ≥1 prior therapy line. Here, we present data for belantamab mafodotin in combination with BorDex. Part 1 (dose escalation) and Part 2 (dose expansion) evaluated belantamab mafodotin (2.5 and 3.4 mg/kg) administered as SINGLE (Day 1) or SPLIT dose (divided equally on Days 1 and 8) in combination with BorDex. Results: As of February 6, 2020, 52 patients were enrolled: 6 patients were enrolled at 2.5 mg/kg single dose and 7 at 3.4 mg/kg single dosing in Part 1, and 45 patients in Part 2. No dose-limiting toxicities were observed. Corneal events (including keratopathy, blurred vision, and dry eye) and thrombocytopenia were the most frequently reported AEs and were clinically manageable. Conclusions: In DREAMM-6, preliminary data demonstrate that the combination of belantamab mafodotin and BorDex has an acceptable safety profile, with no new safety signals identified. Funding: GlaxoSmithKline (207497). Drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Clinical trial information: NCT03544281 .

The past few decades have brought enormous improvements in the cure rates of childhood acute leukemia; about 85% of all children with newly diagnosed acute lymphoblastic leukemia (ALL) and 50–60% with acute myeloid leukemia (AML) experience long-term disease control after multimodal treatments that often include intensified chemotherapy. Relapsed leukemia patients pose a challenging subset of the pediatric leukemic population due to highly resistant disease and, very often, underlying organ dysfunction, calling for development of novel therapeutic approaches and innovative strategies with the power to kill refractory leukemic cells. Advanced laboratory technologies have provided fresh insights into mechanisms of relapse and leukemic cell evolution. Newer formulations of older drugs, antibody-based therapies, and molecularly targeted agents are some of the current strategies under investigation for treatment of relapsed ALL. Whole-genome sequencing has allowed characterization of the transcriptional profile of the leukemic cell, facilitating targeted therapy and leading us one step closer to precision medicine. In this rapidly evolving “race” for better and nontoxic treatments, we find ourselves in an era of the new “CARs”—chimeric antigen receptor(s)—that are defining a role for immunotherapy in childhood cancers of which one was recently approved by US Food and Drug Administration for the treatment of patients up to age 25 years with B-cell precursor acute lymphoblastic leukemia (ALL) who are refractory or in second or later relapse.

ONC201/TIC10 is a small-molecule inducer of the TRAIL gene under current investigation as a novel anticancer agent. In this study, we identify critical molecular determinants of ONC201 sensitivity offering potential utility as pharmacodynamic or predictive response markers. By screening a library of kinase siRNAs in combination with a subcytotoxic dose of ONC201, we identified several kinases that ablated tumor cell sensitivity, including the MAPK pathway–inducer KSR1. Unexpectedly, KSR1 silencing did not affect MAPK signaling in the presence or absence of ONC201, but instead reduced expression of the antiapoptotic proteins FLIP, Mcl-1, Bcl-2, cIAP1, cIAP2, and survivin. In parallel to this work, we also conducted a synergy screen in which ONC201 was combined with approved small-molecule anticancer drugs. In multiple cancer cell populations, ONC201 synergized with diverse drug classes, including the multikinase inhibitor sorafenib. Notably, combining ONC201 and sorafenib led to synergistic induction of TRAIL and its receptor DR5 along with a potent induction of cell death. In a mouse xenograft model of hepatocellular carcinoma, we demonstrated that ONC201 and sorafenib cooperatively and safely triggered tumor regressions. Overall, our results established a set of determinants for ONC201 sensitivity that may predict therapeutic response, particularly in settings of sorafenib cotreatment to enhance anticancer responses. Cancer Res; 75(8); 1668–74. ©2015 AACR.

Allogeneic hematopoietic stem cell transplantation (HSCT) is an increasingly used curative treatment modality, not only for hematologic malignancies but also for a variety of primary immunodeficiencies and nonmalignant hematologic disorders. The expanded use of HSCT is due in large part to improvements in supportive care, T cell depletion approaches, immune suppression, and disease-specific conditioning strategies that have led to improved survival for patients receiving HSCT using alternative donors such as unrelated cord blood, matched or mismatched unrelated adult donors, and partially matched or haploidentical-related donors. While significant hematologic complications associated with well-established approaches for myeloablative matched sibling donor (MSD)-HSCT are relatively uncommon, the increasing use of reduced-intensity conditioning and alternative donor HSCT has been associated with a significant rise in hematologic abnormalities following HSCT. These include autoimmune hemolytic anemia, alloimmune hemolysis due to donor/recipient ABO incompatibility, thrombocytopenia, transplant-associated microangiopathy (TAM), and thromboembolism. Thus, pediatric hematology/oncology specialists who care for pediatric patients who have received HSCT need to be aware of the common presentations and treatment options for hematologic disorders that occur post-HSCT. These HSCT-associated hematologic complications along with their diagnosis and management are discussed in this chapter.

While engraftment is the desired end point of hematopoietic stem cell transplantation (HSCT), the phase of neutrophil recovery can be complicated by two acute entities termed engraftment syndrome (ES) and capillary leak syndrome (CLS). Both ES and CLS result from the release of pro-inflammatory cytokines (e.g., IL-1, TNFα, and IFNγ) from donor cells in response to the recipient’s (or host’s) tissues. ES and CLS can be seen in both autologous and allogeneic HSCT settings. The incidence of ES has been reported to be 7–59% of autologous and 6–82% of allogeneic HSCTs. CLS is much more common than ES and is seen in myeloablative allogeneic HSCT. The clinical manifestations of ES range from mild, self-limited erythroderma, and high fevers to a more severe (and sometimes life-threatening) entity of acute weight gain, pulmonary edema, and hepatic and renal dysfunction with or without encephalopathy. CLS is characterized by weight gain, generalized edema, hypotension, prerenal failure, ascites, intravascular depletion, and pericardial and/or pleural effusions. CLS typically first manifests 1–3 days prior to neutrophil recovery as measured by a detectable ANC in the blood, whereas ES typically occurs shortly after the onset of neutrophil recovery. ES is treated with a short course (usually

Immune reconstitution after hematopoietic stem cell transplantation (HSCT) is critical in order for HSCT recipients to recover their ability to fight all types of infections. Restoration of individual components of the immune system occurs with different timelines. Factors that influence this differential recovery include the type of HSCT, type of donor, donor histocompatibility, donor hematopoietic stem cell source, age of the donor and recipient, conditioning regimen used, the underlying disease or disorder, graft manipulation strategies, and the presence of graft-versus-host disease (GvHD). In general, innate immunity recovers much earlier post-HSCT as compared to adaptive immunity. Complete immune reconstitution may occur from several months to up to 2 years after HSCT. This chapter discusses the typical time course of immune reconstitution by cell type as well as methods to monitor immune reconstitution and an approach to revaccination post-HSCT.

Background In BMA117159, GSK2857916, a humanised (IgG1), afucosylated, anti-BCMA monoclonal antibody conjugated to monomethyl auristatin-F, has shown clinical activity (overall response rate [ORR]=60%; mPFS 12 months [95% CI, 3.1–NE]) as monotherapy in heavily pre-treated patients with MM. Pre-clinical data indicate that GSK’916 induces immunogenic cell death that activates dendritic cells and an antigen-specific T-cell response. PD-L1 overexpression may be a mechanism of immune evasion in MM. Pembrolizumab, a selective, humanised IgG4 anti-PD-1 monoclonal antibody that blocks the interaction of PD-1 with PD-L1 and PD-L2, may synergise with immunomodulatory drugs to enhance tumor suppression. T-cell-dependent antitumor response induced by GSK’916 may be augmented by combining with pembrolizumab. Trial design DREAMM 4 is a Phase I/II, single-arm, open-label, two-part study to evaluate safety and determine the recommended Phase 2 dose (RP2D) and clinical activity of GSK’916 in combination with pembrolizumab in patients with RRMM previously treated with ≥3 prior lines. Part 1 (dose escalation) will evaluate two doses of GSK’916 with a fixed dose of pembrolizumab in up to 12 participants. Modified Toxicity Probability Interval design will guide GSK’916 dose escalation. Primary objectives of Part 1 are to define safety and tolerability and define the RP2D dose of GSK’916 combined with pembrolizumab. Part 2 (dose expansion) will evaluate clinical activity of the RP2D, confirm safety, and collect pharmacokinetic information for GSK’916 in up to 28 participants. Dose expansion may stop early for futility at interim analysis. An additional stopping rule may stop enrolment early if the observed rate of treatment-related ≥Grade 4 AEs equals or exceeds the specified rate (12%). Part 2 objectives are to assess the ORR and confirm the safety profile of GSK’916 and pembrolizumab. Patients will continue combination treatment for 35 cycles or until progression, intolerance, consent withdrawal or death. Enrolment began in March 2019 and is ongoing. Clinical trial identification NCT03848845 (Rel. 19Feb2019). Editorial acknowledgement Clare Slater, PhD, of Fishawack Indicia Ltd, UK, funded by GlaxoSmithKline (GSK). Legal entity responsible for the study GlaxoSmithKline. Funding GlaxoSmithKline and is in collaboration with Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA; drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Disclosure S. Trudel: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: GlaxoSmithKline. A. Nooka: Honoraria (self), Advisory / Consultancy: Emory University Winship Cancer Institute; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self), Research grant / Funding (institution): Takeda; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self), Research grant / Funding (institution): BMS; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self), Research grant / Funding (institution): Janssen; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Celgene; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): GlaxoSmithKline; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Amgen; Honoraria (self), Advisory / Consultancy: Adaptive; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Spectrum; Research grant / Funding (institution): Aduro; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Genentech; Research grant / Funding (institution): KITE pharmaceuticals. D. Fecteau: Shareholder / Stockholder / Stock options, Full / Part-time employment: GlaxoSmithKline. M. Talekar: Shareholder / Stockholder / Stock options, Full / Part-time employment: GlaxoSmithKline. R.C. Jewell: Shareholder / Stockholder / Stock options, Full / Part-time employment: GlaxoSmithKline. D. Williams: Full / Part-time employment: GlaxoSmithKline. J. Evans: Shareholder / Stockholder / Stock options, Full / Part-time employment: GlaxoSmithKline. J. Opalinska: Shareholder / Stockholder / Stock options, Full / Part-time employment: GlaxoSmithKline.

TPS8053 Background: B-cell maturation antigen (BCMA) is a validated therapeutic target in Multiple Myeloma (MM). GSK2857916 is a humanized (IgG1) anti-BCMA monoclonal antibody conjugated to monomethyl auristatin-F via protease resistant maleimidocaproyl linker and produced in afucosylated form to enhance antibody-dependent cellular cytotoxicity. In FTIH study BMA117159, GSK2857916 was well tolerated and showed unprecedented clinical activity [ORR=60%; mPFS 7.9 months (95% CI, 3.1–not estimable)] as monotherapy in heavily pretreated MM patients. GSK2857916 in combination with SoC regimens, could potentially further improve outcomes for patients with relapsed/refractory (RR) MM. Methods: DREAMM 6 is a 2-part study: Part 1 (dose escalation) is evaluating safety and tolerability of 2 doses (2.5 mg/kg and 3.4 mg/kg) of GSK2857916, in combination with SoC regimens in two independent arms: Arm A with Lenalidomide/Dexamethasone, and Arm B with Bortezomib/Dexamethasone. Modified Toxicity Probability Interval design will guide dose escalation and RP2D of GSK2857916 in each arm for Part 2 (cohort expansion). Part 2 will confirm safety, evaluate clinical activity of GSK2857916 RP2D with either combination and collect pharmacokinetic information on GSK2857916, Lenalidomide and bortezomib. Up to 90 subjects previously treated with at least 1 prior line of therapy who have undergone autologous stem cell transplant or are transplant-ineligible will be enrolled; up to 24 in Part 1 and up to 66 in Part 2. Subjects in Arm A will continue combination treatment until progression, intolerance, consent withdrawal or death. Subjects in Arm B will receive up to 8 cycles of GSK2857916 in combination with Bor/Dex and then continue GSK2857916 monotherapy until progression, intolerance, consent withdrawal, or death. Enrolment on study started in October 2018 and is ongoing. Study funded by GlaxoSmithKline; drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. ClinicalTrials.gov Identifier: NCT03544281.

Storing packed red blood cells (pRBCs) increases the potassium concentration. This effect is characterized in citrate phosphate dextrose/citrate phosphate dextrose adenine units but not published for Adsol (AS-5) units. The change in whole-blood potassium concentration in pediatric patients during routine transfusion is also poorly characterized. In this study, pediatric patients undergoing transfusion had pre- and posttransfusion whole-blood potassium measurements. The pRBC unit transfused and the unit's segment were sampled, with potassium concentration measured. In addition, potassium concentration in AS-5 units was measured over 42 days of storage. Unit extracellular potassium increased in AS-5 units after day 7 at 0.83 mmol/L/d. The mean change in patient potassium concentration was 0.08 mmol/L (range, -0.5 to 0.5 mmol/L). No correlation with unit age or unit potassium concentration was identified with change in patient whole-blood potassium concentration. The lack of clinical effect on patient potassium does not support the use of "fresh" pRBC units with routine pediatric transfusion.

ONC201 is the founding member of a novel class of anti-cancer compounds called imipridones that is currently in Phase II clinical trials in multiple advanced cancers. Since the discovery of ONC201 as a p53-independent inducer of TRAIL gene transcription, preclinical studies have determined that ONC201 has anti-proliferative and pro-apoptotic effects against a broad range of tumor cells but not normal cells. The mechanism of action of ONC201 involves engagement of PERK-independent activation of the integrated stress response, leading to tumor upregulation of DR5 and dual Akt/ERK inactivation, and consequent Foxo3a activation leading to upregulation of the death ligand TRAIL. ONC201 is orally active with infrequent dosing in animals models, causes sustained pharmacodynamic effects, and is not genotoxic. The first-in-human clinical trial of ONC201 in advanced aggressive refractory solid tumors confirmed that ONC201 is exceptionally well-tolerated and established the recommended phase II dose of 625 mg administered orally every three weeks defined by drug exposure comparable to efficacious levels in preclinical models. Clinical trials are evaluating the single agent efficacy of ONC201 in multiple solid tumors and hematological malignancies and exploring alternative dosing regimens. In addition, chemical analogs that have shown promise in other oncology indications are in pre-clinical development. In summary, the imipridone family that comprises ONC201 and its chemical analogs represent a new class of anti-cancer therapy with a unique mechanism of action being translated in ongoing clinical trials.

ONC201/TIC10 is a small molecule initially discovered by its ability to coordinately induce and activate the TRAIL pathway selectively in tumor cells and has recently entered clinical trials in adult advanced cancers. The anti-tumor activity of ONC201 has previously been demonstrated in several preclinical models of cancer, including refractory solid tumors and a transgenic lymphoma mouse model. Based on the need for new safe and effective therapies in pediatric non-Hodgkin's lymphoma (NHL) and the non-toxic preclinical profile of ONC201, we investigated the in vitro efficacy of ONC201 in non-Hodgkin's lymphoma (NHL) cell lines to evaluate its therapeutic potential for this disease. ONC201 caused a dose-dependent reduction in the cell viability of NHL cell lines that resulted from induction of apoptosis. As expected from prior observations, induction of TRAIL and its receptor DR5 was also observed in these cell lines. Furthermore, dual induction of TRAIL and DR5 appeared to drive the observed apoptosis and TRAIL expression was correlated linearly with sub-G1 DNA content, suggesting its potential role as a biomarker of tumor response to ONC201-treated lymphoma cells. We further investigated combinations of ONC201 with approved chemotherapeutic agents used to treat lymphoma. ONC201 exhibited synergy in combination with the anti-metabolic agent cytarabine in vitro, in addition to cooperating with other therapies. Together these findings indicate that ONC201 is an effective TRAIL pathway-inducer as a monoagent that can be combined with chemotherapy to enhance therapeutic responses in pediatric NHL.

While apoptosis is critical for maintaining homeostasis in normal cells, defective apoptosis contributes to the survival of cancer cells. TNF-related apoptosis-inducing ligand (TRAIL)-targeted therapy has attracted significant effort for treating cancer, but the clinical results have revealed limitations. The authors review the current status of development of TRAIL-targeted therapy with an outlook towards the future.Recombinant human proteins, small molecules and agonistic monoclonal antibodies targeting death receptors that trigger TRAIL-mediated apoptosis are covered in this article. The authors review both intrinsic and extrinsic apoptotic pathways, highlighting how the apoptosis serves as a promising therapeutic target. They also review different categories of TRAIL pathway targeting agents and provide a brief overview of clinical trials using these agents. The authors discuss the limitations of conventional approaches for targeting the TRAIL pathway as well as future directions.The development of better combination partners for pro-apoptotic TRAIL pathway modulators including novel agents inhibiting anti-apoptotic molecules or targeting alternative resistance pathways may improve the chances for anti-tumor responses in the clinic. Developing predictive biomarkers via circulating tumor cells/DNA, apoptosis signal products, and genetic signatures/protein biomarkers from tumor tissue are also suggested as future directions.

10507 Background: Anti-CD19 CAR-T cell therapies have shown high efficacy in inducing durable marrow responses in patients with relapsed/refractory CD19+ ALL. We now report on outcome of 10 patients with extramedullary (EM) involvement of ALL treated with CAR-T, including 5 patients who had EM disease at time of infusion. Methods: We identified patients treated on pediatric phase 1/2a trials of murine (CTL019) or humanized (CTL119) anti-CD19 CAR-T cells for isolated EM or BM/EM relapse of ALL. EM relapse was defined as involvement of non-CNS site by imaging +/- pathology within 12 months (mos) of infusion. Post infusion, patients had diagnostic imaging done at 1, 3, 6, 9, and 12 mos. Results: Among 97 patients receiving CAR-T, ten (CTL019, n=6; CTL119, n=4) were identified who had EM involvement on average 2.3 mos (range 0-9 mos) prior to infusion; including 5/10 at time of infusion. Sites of EM relapses included testes, sinus, parotid, bone, uterus, kidney and skin, and 5 patients had multiple sites of EM involvement. Patients ranged from 2-4 relapses of their ALL pre-CAR-T. Two had isolated EM relapse (sites were parotid and multifocal bony lesions in one; testis and sinus in second). All 10 patients had undergone hematopoietic stem cell transplantation prior to EM relapse, 2 had received radiation directed to the EM site prior to CAR-T. Five patients evaluated by serial imaging had objective responses: 2 had resolution of EM disease by day 28; 2 had resolution by 3 mos; 1 had continued decrease in size of uterine mass at 3 and 6 mos and underwent hysterectomy at 8 mos with no evidence of disease on pathology. In the 4 patients with prior history of skin or testicular involvement, there was no evidence by exam at day 28. One patient had progressive EM disease within 2 weeks of CAR-T cell infusion and died at 6 weeks. Three relapsed with CD19+ disease [1 skin/medullary- died at 38 mos post CAR-T; 2 medullary (1 died at 17 mos, 1 alive at 28 mos)]. The remaining 6 are alive and well at median follow-up of 10 mos (range 3-16 mos) without recurrence of disease. Conclusions: Single agent CAR-T immunotherapy can induce potent and durable responses in patients with EM relapse of their ALL. Clinical trial information: NCT01626495, NCT02374333.

e19016 Background: Our group has previously shown preclinical in vitro efficacy of novel small molecule, ONC201 across several pediatric NHL cell lines (Talekar et al, 2015) as a monoagent as well as in combination with chemotherapy agents, significantly cytarabine and bortezomib. We investigated the preclinical efficacy of ONC201 and bortezomib combination in vivo in a NHL mouse xenograft model. Methods: Burkitt’s lymphoma cell line (Ramos) transduced with lentiviral GFP was utilized to establish subcutaneous flank xenografts in 5-7 week(wk) old immunodeficient SCID mice [NOD.Cg- Prkdcscid Il2rgtm1Wjl/SzJ]. All tumors were established by Day 10, detected by bioluminescent imaging and were serially imaged x1/wk. Mice were studied in 4 treatment arms (7 mice per arm) as tabulated in the table. Results: Mice in Arms 1, 2 & 3 had continued tumor growth and were humanely euthanized during Wk 3- 4 of treatment when the tumor volume reached the maximum allowable size per the approved institutional IACUC protocol. Mice in Arm 4 showed gross tumor necrosis and had to be euthanized in Wk 4. Upon treatment initiation, 2 mice in each arm were sacrificed at 48 and 72 hours respectively and tumor samples harvested for histology and IHC analysis (TRAIL and CHOP/GADD). Histological analysis revealed that the control group had predominantly viable tumor cells at both 48 & 72 H. The monoagent groups showed minimal cell death with bortezomib alone and modest cell death with ONC201 as monoagent in clustered regions. In contrast, the combination group showed: i) extensive global tumor necrosis with nuclear debris on H&E, ii) prominent TRAIL induction by IHC analysis, and, iii) significant apoptotic cell death accompanied by CHOP /GADD overexpression indicating potential ER stress. Induction of these pharmacodynamic markers in Arm 4 were evident at 48H and more prominent at the 72H. Conclusions: ONC201 effectively synergizes with bortezomib to cause apoptotic tumor cell death in pediatric NHL murine xenograft and merits further investigation. [Table: see text]

103 Background: CD19-targeted CAR T cells show CR rates of 70-95% in B-ALL. Yet a subset of patients do not respond or relapse due to poor CAR T cell expansion and persistence. We hypothesized that PD-1 checkpoint pathway inhibition may improve CAR T cell expansion, function and persistence. Methods: Four children with relapsed B-ALL treated with murine (CTL019) or humanized (CTL119) anti-CD19 CAR T cells received 1-3 doses of the PD-1 inhibitor pembrolizumab (PEM) for partial/no response or prior history of poor CAR T cell persistence starting 14d-2mo post CAR T cell infusion. Results: PEM increased and/or prolonged detection of circulating CAR T cells in all 4 children, with objective responses in 2/4. It was well tolerated, with fever in 2 pts and no autoimmune toxicity. Pts 1-3 received CTL119 for CD19+ relapse after prior murine CD19 CAR T cells. Pt 1 had 1.2% CD19+ residual disease despite expansion with detectable CTL119 by D28 and received PEM at 2mo for progressive disease with decreasing circulating CTL119. CTL119 became detectable at 0.2% of CD3+ cells by flow cytometry, but disease progressed. Pt 2 had no response after initial CTL119 expansion with a rapid disappearance by D28. After CTL119 reinfusion with PEM added 14d later, circulating CAR T cells remained detectable at 4.4% by D28, but disease progressed with decreased CD19 expression. In Pt 3, prior treatment with both CTL019 and CTL119 produced CR with poor CAR T cell persistence followed by CD19+ relapse. CTL119 reinfusion combined with PEM at D14 resulted in CR with prolonged CTL119 persistence (detectable at D50 compared to loss by D36 after 1st CTL119 infusion). Pt 4 received PEM for widespread extramedullary (EM) involvement at D28 post CTL019 infusion despite marrow remission. Initial CTL019 expansion peaked at 63% at D10 and fell to 20% at D28. Resurgence of CTL019 expansion, with a 2nd peak of 70% 11d after PEM, was associated with dramatic reduction in PET-avid disease by 3mo post CTL019. Conclusions: PEM was safely combined with CAR T cells and increased or prolonged CAR T cell detection, with objective responses seen. Immune checkpoint pathways may impact response to CAR T cell treatments and warrant further investigation. Clinical trial information: NCT02374333, NCT02906371.

Congenital self-healing reticulohistiocytosis, also known as congenital self-healing Langerhans cell histiocytosis or Hashimoto-Pritzker disease, is a Langerhans cell histiocytosis. It is characterized by skin lesions in the newborn period in an otherwise healthy infant that show a Langerhans cell infiltrate in the skin on histological analysis. These findings subsequently spontaneously involute. This report describes two newborns who presented at birth with differing presentations of congenital self-healing reticulohistiocytosis. A review of the disorder, including diagnosis and evaluation, is presented.

ONC201 is the founding member of the imipridone class of anti-cancer small molecules that possess a unique core chemical structure. ONC201 is currently being evaluated in several Phase I/II clinical trials for advanced cancers. In the current study, we evaluated the single agent and combinatorial efficacy of ONC201 in preclinical models of acute leukemia and multiple myeloma (MM). In acute leukemia, we evaluated ONC201 anti-cancer effects in acute myeloid leukemia (AML) (Kasumi-1, HL60) and acute lymphoblastic leukemia (ALL) (Reh, Jurkat and MOLT-4) cell lines. We observed a time- and dose-dependent decrease in cell viability for every cell line in the panel (EC50 1-5 µM). Vincristine-resistant cells HL60/VCR were also sensitive to single agent ONC201 with EC50 values on par with corresponding vincristine-sensitive parental cells. Dose- and time-dependent induction of apoptosis was noted in Western blot analysis of caspase-3 cleavage in AML cell lines treated with 2.5 µM or 5 µM of ONC201 for 48 hr. Western Blot analysis further demonstrated inhibition of Akt and Foxo3a phosphorylation in Kasumi-1 cells, in line with the previously reported late-stage signaling effects of ONC201 in solid tumor cells (Allen et al, 2013). Sub-G1 analysis indicated that ONC201 induces apoptosis in ALL cells and a pan-caspase inhibitor reduced ONC201-mediated apoptosis. Western blot analysis revealed ONC201-mediated apoptosis involves PARP cleavage and caspase-9 activation in ALL cells. Anti-apoptotic Bcl-2 family members Bcl-2 and Bcl-xl were downregulated while the pro-apoptotic Bcl-2 family member Bim is upregulated in response to ONC201 treatment in ALL cells. ONC201 also downregulates the inhibitor of apoptosis (IAP) family proteins cIAP1 and cIAP2 in ALL cells. We observed inhibition of Akt phosphorylation upon ONC201 treatment of ALL cells. Fresh AML patient cells were also found to be sensitive to ONC201 in cell viability and caspase 3/7 activity assays at 5µM. We observed that independent clones of cancer cells with acquired resistance to ONC201 were more sensitive to cytarabine compared to parental ONC201-sensitive cancer cells. In addition, ONC201 demonstrated synergistic reduction in cell viability in combination with cytarabine in AML cell lines. Determination of combination indices (CI) revealed synergy at several concentrations (CI 0.336-0.75 in CMK cells). Also, ONC201 combined additively with midostaurin in CMK cells and vincristine in HL60/VCR cells. Thus, ONC201 is a promising combinatorial partner for AML therapies based on these preclinical sensitization results. In accordance with ONC201-mediated activation of the integrated stress response that B cells are highly sensitive to (Kline et al and Ishizawa et al, 2016), MM was identified as one of the most ONC201-sensitive tumor types in the Genomics of Drug Sensitivity in Cancer collection of cell lines. Three human MM cell lines were used for validation (KMS18, MM.1S and RPMI-8226), which revealed a time- and dose-dependent decrease in cell viability (EC50 1-2.5 µM). Bortezomib-resistant cells MM.1S 33X were sensitive to ONC201 as a single agent with EC50 values comparable to bortezomib-sensitive parental cells. We observed an average of 10-fold induction of ONC201-mediated apoptosis using Sub-G1 analyses in MM cells at 5 µM, 48 hrs post-treatment. Rescue of ONC201-mediated apoptosis was demonstrated using the pan-caspase inhibitor (Z-VAD-FMK). In addition, Western blot analysis in MM cells indicated a dose-dependent decrease in the anti-apoptotic protein XIAP which is a key mediator of apoptosis inhibition and is reported to be highly up-regulated in MM cells. Furthermore, ONC201 demonstrated synergistic reduction in cell viability at various concentrations in combination with either ixazomib or dexamethasone, which are used in the clinical treatment of MM, in RPMI8226 cells (CI 0.228-0.75). Also, ONC201 combined additively with bortezomib in RPMI8226 and MM.1S 33X cells. In summary, these preclinical studies support the ongoing ONC201 single agent trials in acute leukemias and MM. Our findings suggest that ONC201 may be an important therapeutic option for patients with hematological malignancies who have developed resistance to approved therapies. Additionally, our results point to specific standard-of-care therapies that may be combined with ONC201 to exert durable responses without adding to the burden of toxicity. Disclosures Prabhu: Oncoceutics: Employment. Tarapore:Oncoceutics: Employment, Equity Ownership. Oster:Oncoceutics: Employment, Equity Ownership. Allen:Oncoceutics: Employment, Equity Ownership. El-Deiry:Oncoceutics: Equity Ownership.

Background Targeted immunotherapy with CTL019, CD19-specific chimeric antigen receptor (CAR)-modified T cells, can produce potent and sustained responses in children with relapsed/refractory acute lymphoblastic leukemia (ALL). However, a subset of patients has limited persistence, which can increase the risk of relapse. Most CAR single chain variable fragment (scFv) domains, including that of CTL019, are of murine origin; therefore, anti-mouse reactivity is one potential cause of immune-mediated rejection that may be overcome by fully human or humanized CAR designs. We developed a humanized anti-CD19 scFv domain and now report on treatment with humanized CD19-directed CAR T cells (CTL119). Design A pilot/phase 1 study of CAR-modified T cells containing a humanized anti-CD19 scFv domain (CTL119) enrolled children and young adults with relapsed/refractory B-ALL with or without prior exposure to a CAR T cell product. Patients previously treated with CD19-specific CAR-modified T cells were eligible if they met 1 of 3 criteria: 1) CD19+ relapse 2) no response to prior CAR T cell therapy or 3) early B cell recovery indicating poor persistence of CAR T cells. Patient-derived T cells were transduced ex vivo with a lentiviral vector encoding a CAR composed of CD3z, 4-1BB, and humanized anti-CD19 scFv domains and activated/expanded with anti-CD3/CD28 beads. The humanized scFv domain was developed by grafting the complementary determining regions of both the heavy and light chains onto human germline acceptor frameworks. Patients received lymphodepletion with cyclophosphamide and fludarabine 1 week prior to infusion with CTL119. Results Thirty children and young adults aged 29 mo-24 yr were infused with CTL119. Eighteen patients had received prior allogeneic stem cell transplant (SCT). Eleven patients who previously received murine-derived CD19-specific CAR-modified T cells (CTL019, n=7; other, n=4) were retreated for B cell recovery (n=5), CD19+ relapse (n=5), or no response to prior CAR T cells (n=1). CNS disease or other extramedullary disease was the indication for enrollment in 6 and 3 patients, respectively. At assessment 1 month after infusion, 26/30 patients (87%) achieved a complete response (CR), defined as morphologic remission with B cell aplasia. Of 11 patients previously treated with murine CD19-specific CAR-modified T cells, 7 (64%) achieved a CR at 1 month, 4 demonstrated no response. Multiparameter flow cytometry for minimal residual disease (MRD) was negative at a detection level of 0.01% in 5/7 responding patients. Two responding patients with positive MRD progressed to CD19+ relapse at 1.6 and 3 mo. In patients with no prior exposure to a CD19 CAR T cell product, MRD-negative CR was achieved in 19/19 patients (100%). One patient relapsed with CD19+ extramedullary disease at 2.8 mo. With a median follow-up of 4.2 mo (range, 1.0-14.1 mo) for all responding patients in both cohorts, 23/26 remain in remission with 1 proceeding to SCT in remission. B cell aplasia, a functional marker of CD19-targeted CAR T cell persistence, continued for 3 months or more in 11/18 patients with adequate follow-up: 1/6 retreatment, 10/12 CAR-naïve. Cytokine release syndrome (CRS) was observed in 28/30 patients and mild in most patients (grade 1, n=6; grade 2, n=18). Three patients experienced grade 3 CRS requiring supplemental oxygen or low-dose vasopressor support and 1 experienced grade 4 CRS requiring high-dose vasopressor and ventilatory support. Severe CRS was successfully managed with the IL6R antagonist tocilizumab in 3 patients. Neurologic toxicity included encephalopathy (n=5) and seizure (n=4) and was fully reversible. Conclusion In the first study of humanized anti-CD19 CAR T cells, CTL119 induced remissions in children and young adults with relapsed/refractory B-ALL, including 64% of patients previously treated with murine CD19-directed CAR T cells and 100% of CAR-naïve patients. Further investigation into CAR T cell persistence and anti-CAR responses will be vital to improve durable remission rates in this highly refractory population. Disclosures Maude: Novartis: Consultancy. Barrett:Novartis: Research Funding. Teachey:Novartis: Research Funding. Shaw:Novartis: Research Funding; Vitality Institute: Research Funding. Brogdon:Novartis: Employment. Scholler:Novartis: Patents & Royalties: Royalties, Research Funding. Marcucci:Novartis: Research Funding. Levine:GE Healthcare Bio-Sciences: Consultancy; Novartis: Patents & Royalties, Research Funding. Frey:Amgen: Consultancy; Novartis: Research Funding. Porter:Novartis: Patents & Royalties, Research Funding; Genentech: Employment. Lacey:Novartis: Research Funding. Melenhorst:Novartis: Research Funding. June:Novartis: Honoraria, Patents & Royalties, Research Funding; Celldex: Consultancy, Equity Ownership; Pfizer: Honoraria; Immune Design: Consultancy, Equity Ownership; Johnson & Johnson: Honoraria; Novartis: Honoraria, Patents & Royalties, Research Funding; Tmunity Therapeutics: Equity Ownership. Grupp:Pfizer: Consultancy; Jazz Pharmaceuticals: Consultancy; Novartis: Consultancy, Research Funding.

Outcome for non-Hodgkin's lymphoma (NHL) patients using conventional treatment standards remains unsatisfactory, particularly in advanced stage/ relapsed disease creating an imminent need for investigating novel treatment strategies. ONC201/TIC10 is a small molecule (Allen et al, 2013) that induces p53-independent cell death in tumor cells while sparing normal cells through inactivation of the prosurvival kinases Akt and ERK. ONC201 is currently entering Phase I/II clinical trials as a monoagent in adult advanced cancers. We have previously shown that ONC201 induces significant cytotoxicity in preclinical models of human lymphomas (Talekar et al, ASPHO 2014). Here, we show that ONC201 is not only effective as a monoagent across several NHL cell lines, but that it also synergizes with several chemotherapeutic agents to cooperatively induce cell death in vitro. We found that ONC201 induces significant apoptosis in a diverse panel of human NHL cell lines at low micromolar concentrations (1.3 to 5.06 uM). Increased surface TRAIL and surface DR5 expression was noted in a dose-dependent manner across representative cell lines. The increase in surface TRAIL correlated with increase in sub-G1 DNA content, which suggests that TRAIL may serve as a potential biomarker of response to ONC201. ONC201-induced apoptosis was inhibited using a pan-caspase inhibitor and was blocked by an anti-TRAIL antibody RIK-2, which indicate induction of TRAIL-dependent cell death. Western blot analysis of ONC201-treated NHL cells suggests ERK inhibition and Foxo3a activation as a potential mechanism of cytotoxicity via TRAIL induction. In agreement with this notion, we also observed upregulation of PARP & DR5 and caspase-3 activation in response to ONC201 treatment. We further found that ONC201 synergizes to potentiate cytotoxicity with several chemotherapeutic agents approved for NHL treatment, particularly anthracyclines (doxorubicin), nitrogen mustard (bendamustine), antimetabolite (cytarabine) and proteasome inhibitor (bortezomib) via cell viability experiments that were corroborated by apoptosis assays. Together these results suggest that ONC201 is a potent antitumor agent in NHL as monoagent and in combination with several approved therapies that may be explored in phase Ib/II trials. Citation Format: Mala Kiran Talekar, David Dicker, Joshua Allen, Wafik El-Deiry. ONC201/TIC10 is effective as a monoagent and synergizes with chemotherapy to induce cell death in non-Hodgkin's lymphoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5387. doi:10.1158/1538-7445.AM2015-5387

ONC201/TIC10 is a potent small molecule anti-tumor agent in several types of solid tumors and lymphomas. ONC201/TIC10 is on track to enter clinical trials for patients with advanced cancer in 2014, with IND issued by the FDA in March, 2014. Early trials will evaluate the safety and efficacy of ONC201/TIC10 as a monoagent in hematological malignancies. In the current study, we evaluated the anti-cancer effects of the small molecule in Acute Lymphoblastic Leukemia (ALL). Analysis of cell viability by the CellTiter-Glo method revealed that ONC201/TIC10 treatment reduces the viability of three ALL cell lines (Reh, Jurkat, MOLT-4) in a dose- (2.5/5/10 μM) and time-dependent manner (24/48/72 h). We have previously reported that ONC201/TIC10-mediated reduction in cell viability and apoptosis in various types of solid tumors occurs at 60/72 h. Interestingly, ONC201/TIC10 reduces the viability of ALL cell lines within 24/48 h at the indicated doses. An inactive TIC10 isomer compound synthesized by Medkoo Biosciences with a structure related to the active ONC201/TIC10 compound does not reduce the viability of ALL cells. Sub-G1 analysis indicated that ONC201/TIC10 induces apoptosis in ALL cells and a pan-caspase inhibitor reduces ONC201/TIC10-mediated apoptosis. Western blot analysis was used to further investigate the mechanism of ONC201/TIC10-mediated apoptosis. ONC201/TIC10-mediated apoptosis involves PARP cleavage and caspase-9 activation. Anti-apoptotic Bcl-2 family members Bcl-2 and Bcl-xl are downregulated while the pro-apoptotic Bcl-2 family member Bim is upregulated in response to ONC201/TIC10 treatment. ONC201/TIC10 also downregulates the inhibitor of apoptosis (IAP) family proteins cIAP1 and cIAP2. We have previously shown that the anti-tumor effect of ONC201/TIC10 involves inhibition Akt and ERK phosphorylation resulting in Foxo3a activation and TRAIL-gene transcription. We observed inhibition of Akt phosphorylation upon ONC201/TIC10 treatment of ALL cells. Thus, ONC201/TIC10 holds promise as a novel agent for the treatment of ALL based on its robust activity in preclinical models of the disease. Our ongoing studies are evaluating the impact of this novel therapy on ALL cells with different translocations, and are introducing combination therapy with ONC201/TIC10 for ALL. Figure 1 Figure 1. Disclosures Allen: Oncoceutics: Employment, Equity Ownership, Patents & Royalties. El-Deiry:Oncoceutics, Inc.: Equity Ownership, Patents & Royalties.

Quinacrine is a bioactive acridine derivative which has been used for treatment of malaria, giardiasis, systemic lupus erythematosus, and rheumatoid arthritis. In searching for p53 pathway activating agents for cancer therapy, we found that quinacrine stabilizes p53 and induces p53-dependent and p53-independent tumor cell death. Quinacrine also induces expression of TRAIL Death Receptor 5 (DR5) and reduces expression of anti-apoptotic Mcl-1 in tumor cells. These activities predict synergies with TRAIL (tumor necrosis factor-related apoptosis inducing ligand) and chemotherapeutic agents in inducing extrinsic and intrinsic pathway mediated apoptosis. In addition, quinacrine suppresses NFkB activity in tumor cells. Clinical trials have been ongoing for treatment of solid tumors including colon cancer, renal cancer, prostate cancer, and non-small cell lung cancer with quinacrine in combination with chemotherapy or tyrosine-kinase inhibitors, however, the therapeutic potential of quinacrine in blood cancer cells has not been established. We tested quinacrine on hematopoietic malignant cells, which included cell lines of myeloid leukemia, lymphoblastic leukemia, B-cell lymphoma, T-cell lymphoma, and multiple myeloma. We found that quinacrine induces massive cell death in the cell lines tested, at concentrations from as less as 1 microM to 5 microM, 2-10 times lower than required to induce solid tumor cell death. Quinacrine synergizes with TRAIL in inducing cell death of TRAIL-sensitive cells and reverses resistance in TRAIL-resistant cells. Quinacrine also synergizes with chemotherapeutic agents, such as antimetabolites, alkylating agents, and tyrosine kinase inhibitors, in inducing apoptosis of hematopoietic cancer cell lines. Our work supports translational efforts to advance the use of quinacrine from bench to clinic and provides rationale for combination chemotherapeutic regimes for treatment of hematopoietic malignancies. Disclosures No relevant conflicts of interest to declare.

Outcome for Non-Hodgkin lymphoma (NHL) patients using conventional treatment standards remains unsatisfactory, particularly in advanced stage/ relapsed disease creating an imminent need for investigating novel treatment strategies. ONC201/TIC10 is a small molecule (Allen et al, 2014) that induces p53-independent cell death in tumor cells (sparing normal cells) through inactivation of prosurvival kinases Akt and ERK. ONC201 is scheduled to enter Phase I/II clinical trials as a monoagent for advanced cancers in adults in 2014. We have previously shown that ONC201 induces significant cytotoxicity in preclinical models of human lymphomas (Talekar et al, ASPHO 2014). Here, we show that ONC201 is not only effective as a monoagent across several NHL cell lines, but that it also synergizes with several chemotherapeutic agents to cooperatively induce cell death in vitro. We found that ONC201 induces significant apoptosis in a diverse panel of seven human NHL cell lines at low micromolar concentrations (1.3 to 5.06 uM). Increased surface TRAIL and surface DR5 expression was noted in a dose-dependent manner across representative cell lines. The increase in surface TRAIL correlated with increase in subG1 DNA content, which suggests TRAIL as a potential biomarker of ONC201 response. ONC201-induced apoptosis was inhibited using a pan-caspase inhibitor and was blocked by an anti-TRAIL antibody RIK-2. Western blot analysis of ONC201-treated representative cell lines suggests ERK inhibition and Foxo3a activation as a potential mechanism of cytotoxicity via TRAIL induction. In agreement with this notion, we observed upregulation of PARP & DR5 and caspase-3 activation in response to ONC201 treatment. We further found that ONC201 synergizes to potentiate cytotoxicity with several chemotherapeutic agents approved for NHL treatment, particularly anthracyclines (doxorubicin), nitrogen mustard (bendamustine), antimetabolite (cytarabine) and proteasome inhibitor (bortezomib) via CellTiter-Glo cell viability experiments that were corroborated by apoptosis assays. Together these results suggest that ONC201 is a potent antitumor agent in NHL as monoagent and in combination with approved therapies. The ultimate goal of this project is to provide a preclinical rationale for a phase Ib/II trial of ONC201 as a combination therapy in pediatric lymphoma. Disclosures Allen: Oncoceutics, Inc.: Employment, Equity Ownership, Ownership interests (including stock options) in a start-up company, the stock of which is not publicly traded Other, Patents & Royalties. El-Deiry:Oncoceutics, Inc.: Equity Ownership, Founder and Shareholder in Oncoceutics, Inc. The potential conflict of interest has been disclosed to and is being managed by his academic employer. Other.

Despite significant progress in 5-year survival rates for Non-Hodgkin's Lymphoma (NHL) using conventional treatment standards, there is still a need for improved therapies especially for children and adolescents with advanced-stage disease and for those who relapse after conventional therapy. TRAIL (TNF-related apoptosis-inducing ligand) is an endogenous protein that induces apoptosis selectively in cancer cells by binding to death receptors DR4 or DR5. Our laboratory identified a small molecule, TIC10, that induces TRAIL gene transcription and TRAIL-dependent cell death and overcomes the most critical efficacy-limiting drug properties of available TRAIL-based therapies. Selective advantages of TIC10 include longer half-life, stimulation of TRAIL and death receptor expression, stability, lower production cost, and ability to cross the intact blood-brain barrier. Our lab has reported that TIC10 is orally active and has potent anti-tumor effects in several preclinical models, including prolonging survival of lymphoma-bearing Eu-myc transgenic mice. We hypothesize that TIC10 induces apoptosis in human lymphoma cell lines. We selected a diverse sub-type panel of lymphoma cell lines [BJAB, Daudi, Ramos and Raji (Burkitt's lymphoma); Karpas299 (T-cell NHL), and UPN2 (Mantle Cell lymphoma)] to assess lymphoma sensitivity to TIC10. Cell viability assays demonstrated sharp dose-response curves in all of the above cell lines at 72 hours post-treatment. Quantitative analysis of these relationships yielded TIC10 IC50 values in the range of 1.3 to 2.9 uM, which is comparable to the reported activity of TIC10 in other tumor types. Using low micromolar dose ranges, Daudi and Ramos cell lines were treated with TIC10 and sub-G1 analysis by flow cytometry revealed that TIC10 induced significant levels of apoptosis of both the treated cell lines at 72 hours post-treatment in a dose-dependent manner [Daudi cells: untreated cells: 9.4%; increase in sub-G1 content to 39% (4.3 fold); Ramos cells: untreated cells: 41.4%; increase in sub-G1 content to 72.1% (1.74 fold)]. These preliminary findings suggest that TIC10 induces apoptosis in human lymphoma cell lines at low micromolar concentrations. Our lab has previously established that TIC10 synergizes with several approved antitumor agents such as taxanes and sorafenib in other tumor types. We further hypothesize that TIC10 will have synergistic cytotoxic effects in lymphoma in combination with standard chemotherapeutic agents used to treat lymphoma. We have established monoagent dose-response relationships for gemcitabine, etoposide, doxorubicin and vincristine in the above mentioned lymphoma panel of cell lines. In conclusion, TIC10 is a first-in-class therapy that has apoptotic activity in human lymphoma cells that is promising as a monoagent and may be enhanced by combination with approved therapies to improve the standard of care in this setting. Citation Format: Mala K. Talekar, Joshua E. Allen, Wafik S. El-Deiry. TRAIL-inducing agent -TIC10 and combinatorial therapeutics in pediatric lymphoma: a targeted approach. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-307. doi:10.1158/1538-7445.AM2013-LB-307