Citations

Eosinophils are bone-marrow-derived granulocytes known for their ability to facilitate clearance of parasitic infections and their association with asthma and other inflammatory diseases. The purpose of this review is to discuss the currently available human observational and animal experimental data linking eosinophils to the immunologic response in solid organ transplantation. First, we present observational human studies that demonstrate a link between transplantation and eosinophils yet were unable to define the exact role of this cell population. Next, we describe published experimental models and demonstrate a defined mechanistic role of eosinophils in downregulating the alloimmune response to murine lung transplants. The overall summary of this data suggests that further studies are needed to define the role of eosinophils in multiple solid organ allografts and points to the possibility of manipulating this cell population to improve graft survival.

Background The epidemiology of ventricular arrhythmias (VAs) in patients with advanced heart failure (HF) is not well defined. Methods and Results Residents of Olmsted County, Minnesota, with advanced HF from 2007 to 2017 were identified using the 2018 European Society of Cardiology criteria. Billing codes were used to capture VAs; severe VAs requiring emergency care were defined as events associated with emergency department visits or hospitalizations. The cumulative incidence of VAs postadvanced HF was estimated with the Kaplan–Meier method. Multivariable Cox analyses were used to determine the following: (1) Predictors of severe VAs postadvanced HF; and (2) Impact of severe VAs on mortality. Of 936 patients with advanced HF, 261 (27.9%) had a history of VA. The 1‐year cumulative incidence of severe VAs postadvanced HF was 5.4%. Prior VAs (hazard ratio [HR] 2.22 [95% CI, 1.26–3.89], P =0.006) and left ventricular ejection fraction <40% (HR, 3.79 [95% CI, 1.72–8.39], P <0.001) were independently associated with increased severe VA risk postadvanced HF. New‐onset severe VAs were associated with increased mortality (HR, 4.41 [95% CI, 2.80–6.94]; P <0.001), whereas severe VAs in patients with prior VAs had no significant association with mortality risk (HR, 1.08 [95% CI, 0.65–1.78]; P =0.77). Severe VAs were associated with increased mortality in patients without implantable cardioverter defibrillators (HR, 4.89 [95% CI, 2.89–8.26]; P <0.001), but not in patients with implantable cardioverter defibrillators (HR, 1.42 [95% CI, 0.92–2.19]; P =0.11). Conclusions Patients with left ventricular ejection fraction <40% and prior VAs have increased risk of severe VA postadvanced HF. New‐onset severe VAs or severe VAs without implantable cardioverter defibrillators postadvanced HF are associated with increased mortality.

AbstractBackgroundData regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation following mitral valve surgery (MVS) is limited. Catheter ablation (CA) can be challenging given perivalvular substrate in the setting of mitral annuloplasty or prosthetic valves.ObjectiveTo investigate the characteristics, safety, and outcomes of radiofrequency CA in patients with prior MVS and ventricular arrhythmias (VA).MethodsWe identified consecutive patients with prior MVS who underwent CA for VT or PVC between January 2013 and December 2018. We investigated the mechanism of arrhythmia, ablation approach, peri‐operative complications, and outcomes.ResultsIn our cohort, 31 patients (77% men, mean age 62.3 ± 10.8 years, left ventricular ejection fraction 39.2 ± 13.9%) with prior MVS underwent CA (16 VT; 15 PVC). Access to the left ventricle was via transseptal approach in 17 patients, and a retrograde aortic approach was used in 13 patients. A combined transseptal and retrograde aortic approach was used in one patient, and a percutaneous epicardial approach was combined with trans‐septal approach in one patient. Heterogenous scar regions were present in 94% of VT patients and scar‐related reentry was the dominant mechanism of VT. Forty‐seven percent of PVC patients had abnormal substrate at the site targeted for ablation. Clinical VA substrates involved the peri‐mitral area in six patients with VT and five patients with PVC ablation. No procedure‐related complications were reported. The overall recurrence‐free rate at 1‐year was 72.2%; 67% in the VT group and 78% in the PVC group. No arrhythmia‐related death was documented on long‐term follow‐up.ConclusionCA of VAs can be performed safely and effectively in patients with MVS.

Abstract Leukemia relapse and treatment related mortality (TRM) remain major obstacles for successful allogeneic hematopoietic cell transplantation (allo-HCT). The number of induction cycles using intensive chemotherapy at AML diagnosis to achieve complete remission (CR) and the number of consolidation cycles and disease status at the time of allo-HCT for patients with acute myeloid leukemia (AML) may each affect TRM and relapse rates. We investigated the impact of the number of induction/consolidation cycles and disease status on the success of allo-HCT in 3113 AML patients reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) (2008-2019). They received allo-HCT in first CR or with persistent leukemia (primary induction failure-PIF) receiving myeloablative (MA) or reduced-intensity (RIC) conditioning. 1473 AML patients (median age, 47 years) in CR received MAC; 862 (58%) achieved CR after 1 cycle of intensive induction chemotherapy and 74% of these had no evidence of measurable residual disease (MRD). 454 (31%) patients required 2 cycles to CR (72 % MRD negative) and 157 (11%) patients (69% MRD negative) after ≥ 3 cycles. The overall survival (OS), relapse and TRM by induction cycle number is shown in Table 1. Multivariate analysis demonstrated that CR after 1 cycle led to higher OS vs. 2 cycles (HR 1.32 95%CI 1.11-1.56, p&lt; 0.01) or ≥ 3 cycles (HR 1.47 95%CI 1.16-1.87, p&lt; 0.01), while OS after 2 cycles or ≥ 3 cycles were similar (HR 1.2 95%CI 0.87-1.4, p=0.38). Higher TRM was observed in patients receiving 2 or ≥ 3 cycles vs. only 1 induction cycles (HR 1.34 95%CI 1.05-1.72, p&lt; 0.02). Relapse risk was greater in those needing ≥ 3 cycles to achieve CR. Consolidation therapy after CR was associated with improved OS vs. no consolidation therapy (HR 1.57 95%CI 1.24-1.99, p&lt; 0.01). The need for ≥2 induction cycles plus consolidation therapy was associated with higher TRM (HR 1.34 95%CI 1.05-1.72, p&lt; 0.02). 1162 AML patients (median age, 63 years) in CR received allo-HCT after RIC; 714 (61%) achieved CR after 1 cycle of induction chemotherapy (72% MRD negative); 310 (27%) patients after 2 cycles (67% MRD negative) and 138 (12%) patients (58% MRD negative) after ≥ 3 cycles (Table 1). Multivariate analysis demonstrated that the number of induction cycles did not affect the OS or TRM. Relapse risk was greater in patients requiring ≥2 cycles to achieve CR. The use of consolidation therapy did not affect OS or TRM. MRD status at the time of allo-HCT did not have a significant impact on OS, TRM and relapse rates after either MA or RIC conditioning. 478 AML patients received allo-HCT after PIF (328 patients with MAC [median age, 51 years], 150 patients RIC [median age, 61 years], Table 1). After MAC, OS and relapse were significantly worse in PIF patients compared to any CR patients (p&lt;0.01). After RIC, relapse was significantly more frequent in PIF patients vs. CR patients after 1 or more induction cycles (p&lt;0.01). TRM was similar for PIF vs CR patients after MAC or RIC allo-HCT. These data demonstrate that among patients eligible for allo-HCT, the need for only one induction cycle to achieve CR, particularly when combined with consolidation therapy is associated with better outcomes after MA conditioning. Achieving CR prior to allo-HCT needing one or more induction cycles is associated with lower relapse rates and improved OS compared to patients with PIF that receive allo-HCT. Figure 1 Figure 1. Disclosures de Lima: BMS: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotec: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hourigan: Govt. COI: Other. Litzow: Omeros: Other: Advisory Board; Pluristem: Research Funding; Jazz: Other: Advisory Board; AbbVie: Research Funding; Amgen: Research Funding; Actinium: Research Funding; Astellas: Research Funding; Biosight: Other: Data monitoring committee. Saber: Govt. COI: Other. Weisdorf: Incyte: Research Funding; Fate Therapeutics: Research Funding.

Abstract Background CD47 is an innate immune checkpoint that binds signal regulatory protein alpha (SIRPα) and delivers a "don't eat me" signal to suppress macrophage phagocytosis. Overexpression of CD47 can allow tumor cells to escape immune surveillance. TTI-621 (SIRPαFc) is a fusion protein consisting of the CD47 binding domain of human SIRPα linked to the Fc region of human IgG1, designed to enhance phagocytosis and antitumor activity by blocking the CD47-SIRPα interaction between malignant cells and macrophages, and engaging Fcγ receptors. Here we report updates from the dose optimization part of the first-in-human study of TTI-621 (NCT02663518), testing dose levels between 0.5-2.0 mg/kg in patients with cutaneous T-cell lymphoma (CTCL). Methods This study has been conducted in 4 parts. Part 1 tested increasing weekly intravenous doses of TTI-621 based on 3+3 escalation. The maximum tolerated dose was initially determined to be 0.2 mg/kg based on dose limiting toxicity (DLT) of thrombocytopenia [defined as Grade (Gr) 4 of any duration]. Expanded testing followed in patients with hematologic malignancies. In Part 2, most patients received 0.2 mg/kg; however, based on investigator discretion, a subset of patients received escalating doses up to 0.5 mg/kg. In Part 3, patients with T-cell lymphomas received stepwise dose escalations from 0.2 to 0.5 mg/kg over the first 5−8 weeks. Part 4 (dose optimization) of this study, is currently ongoing with weekly TTI-621 treatment escalating in a standard 3+3 manner through 5 planned dose levels including 0.5, 0.7, 1, 1.4, and 2 mg/kg. Dose optimization is being assessed in patients with CTCL. The DLT criteria was modified to require Gr 4 thrombocytopenia lasting &gt;72 hours. Safety monitoring includes weekly clinical laboratories and assessments of adverse events (AEs) per CTCAE v 4.03. Blood samples are obtained for pharmacokinetics and disease assessments are performed per Olsen's criteria. Results In Parts 1−3 (n=214), the most common related AEs were infusion-related reaction (IRR, 43%; 3% Gr ≥3), thrombocytopenia (30%; 22% Gr ≥3), chills (22%; 0% Gr ≥3), and fatigue (16%; 1% Gr ≥3). Objective responses to single agent TTI-621 were achieved in 14/71 (20%) NHL pts including CTCL (n=42, 1 CR, 7 PRs), PTCL (n=22, 2 CRs, 2 PRs) and DLBCL (n=7, 1 CR, 1 PR). In Part 4 as of April 12, 2021, 24 patients (17M/7F, median age 65 years) have enrolled into the 5 dose cohorts including 9 patients in the 2.0 mg/kg dose level. CTCL subtypes enrolled include mycosis fungoides (MF, n=18) and Sézary syndrome (SS, n=6). Disease stage was advanced (≥IIB) in 16 (67%) patients and a median of 3 (range 1−12) prior systemic therapies were received. Related AEs occurred in 19 (79%; 33% Gr ≥3) patients including infusion-related reaction (IRR, 50%; 13% Gr ≥3), thrombocytopenia (33%; 25% Gr ≥3), and neutropenia and headache, (13%, 0% Gr ≥3, each). Thrombocytopenia generally occurred on dosing days, and typically recovered within 2-4 days. A total of 15 IRRs have occurred in 12 (50%) patients at all doses levels. Most IRRs occurred during initial infusions only and typically resolved within the day of occurrence. The occurrence of Gr 3 IRRs prompted the addition of corticosteroids to the pre-medication regimen which largely prevent their occurrence. Aside from IRRs and thrombocytopenia which was manageable, AEs were predominantly Gr ≤2. Pharmacokinetic results reveal continued dose-dependent increases in exposure. Objective responses have been observed in 4 of 20 (20%) evaluable patients to date, including 3 partial responses in 14 patients with MF and 1 complete response in 6 patients with SS. Treatment is ongoing in the patient who achieved CR (10+ months) and in 2 of 3 patients who achieved PR (3 and 4 months). A third patient who achieved PR elected to discontinue study treatment at 5 months to pursue allogeneic stem and progenitor cell transplantation. Conclusions Preliminary results from dose optimization testing indicate that weekly infusions of TTI-621 up to 2 mg/kg are generally well tolerated. In Part 4, an overall response rate of 20% has been observed thus far in patients with CTCL. Testing of TTI-621 in alternative dosing schedules is in progress. With demonstrated good tolerability and robust single agent antitumor activity in heavily pre-treated patients, additional testing of TTI-621 beyond relapsed/refractory lymphoma has started. Disclosures Horwitz: Affimed: Research Funding; ADC Therapeutics, Affimed, Aileron, Celgene, Daiichi Sankyo, Forty Seven, Inc., Kyowa Hakko Kirin, Millennium /Takeda, Seattle Genetics, Trillium Therapeutics, and Verastem/SecuraBio.: Consultancy, Research Funding; Acrotech Biopharma, Affimed, ADC Therapeutics, Astex, Merck, Portola Pharma, C4 Therapeutics, Celgene, Janssen, Kura Oncology, Kyowa Hakko Kirin, Myeloid Therapeutics, ONO Pharmaceuticals, Seattle Genetics, Shoreline Biosciences, Inc, Takeda, Trillium Th: Consultancy; Aileron: Research Funding; Celgene: Research Funding; C4 Therapeutics: Consultancy; Crispr Therapeutics: Research Funding; Daiichi Sankyo: Research Funding; Forty Seven, Inc.: Research Funding; Kura Oncology: Consultancy; Kyowa Hakko Kirin: Consultancy, Research Funding; Millennium/Takeda: Research Funding; Myeloid Therapeutics: Consultancy; ONO Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Research Funding; Secura Bio: Consultancy; Shoreline Biosciences, Inc.: Consultancy; Takeda: Consultancy; Trillium Therapeutics: Consultancy, Research Funding; Tubulis: Consultancy; Verastem/Securabio: Research Funding. Foran: pfizer: Honoraria; novartis: Honoraria; servier: Honoraria; bms: Honoraria; revolution medicine: Honoraria; taiho: Honoraria; syros: Honoraria; sanofi aventis: Honoraria; certara: Honoraria; gamida: Honoraria; OncLive: Honoraria; abbvie: Research Funding; boehringer ingelheim: Research Funding; takeda: Research Funding; trillium: Research Funding; aptose: Research Funding; actinium: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Lue: Epizyme: Consultancy; TG Therapeutics: Consultancy; Kymera Therapeutics: Research Funding; AstraZeneca: Speakers Bureau; Kura Oncology: Consultancy. Sawas: Affimed: Research Funding; Roche: Current equity holder in publicly-traded company; Flat Iron Health: Current Employment; Seattle Genetics: Honoraria; Acrotech: Honoraria; Daiichi-Sankyo: Speakers Bureau; Seattle Genetics: Speakers Bureau; Gilead: Speakers Bureau. Feldman: Alexion, AstraZeneca Rare Disease: Honoraria, Other: Study investigator. Sokol: Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Mei: Janssen: Honoraria; EUSA: Honoraria; TG Therapeutics: Research Funding; Epizyme: Research Funding; BMS: Research Funding; Morphosys: Research Funding; Beigene: Research Funding. Flinn: AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Villa: Janssen: Honoraria; Roche: Honoraria; Lundbeck: Honoraria; Celgene: Honoraria; Seattle Genetics: Honoraria; AbbVie: Honoraria; AstraZeneca: Honoraria; Gilead: Honoraria; NanoString Technologies: Honoraria. Percival: Pfizer: Research Funding; Abbvie: Research Funding; Biosight: Research Funding; BMS/Celgene: Research Funding; Cardiff Oncology: Research Funding; Glycomimetics: Research Funding; Nohla Therapeutics: Research Funding; Oscotec: Research Funding; Trillium: Research Funding. Savage: Seattle Genetics: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Other: Institutional clinical trial funding; Merck: Consultancy, Honoraria, Other: Institutional clinical trial funding; AbbVie: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Roche: Research Funding; Takeda: Other: Institutional clinical trial funding; Beigene: Other: Institutional clinical trial funding; Genentech: Research Funding. Diefenbach: Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; MEI: Consultancy, Research Funding; Gilead: Current equity holder in publicly-traded company; IMab: Research Funding; Celgene: Research Funding; Trillium: Research Funding; Incyte: Research Funding; AbbVie: Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; IGM Biosciences: Research Funding. Kim: Kyowa Kirin: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Innate: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Corvus: Membership on an entity's Board of Directors or advisory committees, Research Funding; Trillium: Research Funding; Galderma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Elorac: Research Funding; Portola: Membership on an entity's Board of Directors or advisory committees, Research Funding; Soligenix: Research Funding; Eisai: Research Funding; CRISPR: Research Funding; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion, AstraZeneca Rare Disease: Other: Study investigator; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Horizon: Research Funding. Lin: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Catalano: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Petrova: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Uger: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Molloy: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Large: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Bruns: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

Abstract Background: Mcl-1 is an anti-apoptotic protein in the Bcl-2 family that contributes to the pathophysiology of certain B-cell malignancies and AML. Dependence on Mcl-1 is associated with poor prognosis, and increased Mcl-1 levels is a common mechanism of resistance to venetoclax. Voruciclib (VORU), a potent oral CDK9 inhibitor (Ki &lt;10 nM), was shown to decrease Mcl-1 protein expression in preclinical models, supporting its evaluation as a single agent and in combination with venetoclax in AML and B-cell malignancies. In two dose escalation phase 1 studies of VORU in patients (pts) with solid tumors, the maximum tolerated dose (MTD) was established at 350 mg when administered daily continuously and 600 mg when administered on days 1 to 14 in a 21-day cycle. Based on concentrations needed for antitumoral activity in preclinical models, pharmacokinetic (PK) results predict a dose of ~200 mg could be sufficient for target inhibition. The present phase 1 study is the first to evaluate the MTD, recommended Phase 2 dose (RP2D), dose-limiting toxicities (DLT), safety, PK, and preliminary efficacy of VORU in pts with relapsed/refractory hematologic malignancies (NCT03547115). Methods: Pts with relapsed B-cell lymphoma, chronic lymphocytic leukemia (CLL), or AML were eligible if age ≥18 years, ECOG performance status ≤1, disease progression after failure of standard therapies, adequate hepatic and renal function, and no prior CDK9 therapy. Dose escalation started at 50 mg, followed a 3+3 design, and DLTs were assessed in Cycle 1. Initially VORU was administered once daily continuously in a 28-day cycle (Group I). After 2 DLTs were observed at 100 mg, administration was changed to once daily on days 1 to 14 in a 28-day cycle (Group II), patients with prior allogeneic transplant were excluded, and dose escalation (100, 150, 200 mg) proceeded in separate cohorts for AML and B-cell malignancies. Disease response was assessed by the Lugano, iwCLL, and 2017 ELN criteria. Results: To date 28 pts have been enrolled: 14 AML, 7 diffuse large B-cell lymphoma (DLBCL), 3 follicular lymphoma (FL), 2 CLL and 2 mantle cell lymphoma. Group I enrolled 16 pts, 8 each at 50 mg and 100 mg. Group II enrolled 12 pts, 10 with AML administered VORU at 100, 150 or 200 mg and 2 pts with B-cell malignancies administered VORU at 100 mg. Dose escalation in AML is completed. Median age was 71 years (range 40-90) and 54% of pts were male. Pts were generally heavily pretreated, with a median of 3 prior therapies (range 1-8). Median number of VORU cycles administered was 2 (range 1-4). Drug-related serious adverse events (SAEs) were reported in Group I only and consisted of 2 DLT of Gr 3 pneumonitis at 100 mg, both in AML pts treated with allogeneic transplant followed by GVHD in the preceding 12 months, one of whom also had a concurrent Gr 3 differentiation syndrome (DS), and 1 SAE not meeting DLT criteria, a Gr 3 hypoxemic respiratory failure in Cycle 4 in a pt with DLBCL at 50 mg. One AML pt developed ischemic bowel thought to be due to disease progression. Symptoms consistent with DS were observed in 4 AML pts. In Group II, no DLTs have been observed to date and there were no Gr 3-5 drug-related adverse events reported. There is no evidence of significant drug-related neutropenia in pts with B-cell malignancies. To date, in Groups I and II combined, 1 AML pt achieved a morphologic leukemia-free state, 2 AML pts achieved stable disease (SD), and 3 pts with B-cell malignancies had a best response of SD, including 1 FL pt who achieved a 42% reduction in SPD, and 1 CLL pt with relapsed disease after chemoimmunotherapy, venetoclax, and ibrutinib who had stable blood counts. Conclusions: VORU at doses up to 200 mg administered on 14 consecutive days in a 28-day cycle was well tolerated with no DLTs observed. Consistent with the phase 1 studies in solid tumors, no significant myelosuppression was seen in pts with B-cell malignancies. The safety profile does not indicate overlapping toxicities with venetoclax. Disease stabilization was observed in heavily pretreated pts and differentiation syndrome was observed in AML indicating biologic activity. Enrollment at 200 mg will continue in an expansion cohort in AML. A forthcoming protocol amendment will evaluate VORU in combination with venetoclax in pts with relapsed AML to exploit the dual inhibition of Bcl-2 and Mcl-1. Disclosures Konopleva: Sanofi: Other: grant support, Research Funding; Ablynx: Other: grant support, Research Funding; F. Hoffmann-La Roche: Consultancy, Honoraria, Other: grant support; KisoJi: Research Funding; Novartis: Other: research funding pending, Patents & Royalties: intellectual property rights; Genentech: Consultancy, Honoraria, Other: grant support, Research Funding; Reata Pharmaceuticals: Current holder of stock options in a privately-held company, Patents & Royalties: intellectual property rights; Stemline Therapeutics: Research Funding; Eli Lilly: Patents & Royalties: intellectual property rights, Research Funding; AstraZeneca: Other: grant support, Research Funding; Rafael Pharmaceuticals: Other: grant support, Research Funding; Agios: Other: grant support, Research Funding; Ascentage: Other: grant support, Research Funding; Calithera: Other: grant support, Research Funding; Cellectis: Other: grant support; Forty Seven: Other: grant support, Research Funding; AbbVie: Consultancy, Honoraria, Other: Grant Support, Research Funding. Brander: Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; BeiGene: Research Funding; DTRM: Research Funding; Genentech: Consultancy, Research Funding; Juno Therapeutics/Celgene/Bristol Myers Squibb: Research Funding; Pfizer: Consultancy, Other: Biosimilars outcomes research panel; TG Therapeutics: Consultancy, Research Funding; Ascentage: Research Funding; LOXO: Research Funding; AstraZeneca: Research Funding; MEI Pharma: Research Funding; ArQule: Research Funding; AbbVie: Consultancy, Other: informCLL registry steering committee, Research Funding; Verastem: Consultancy; Novartis: Research Funding; NCCN: Other: panel member; ArQule/Merck: Consultancy. Patel: TG Therapeutics: Consultancy, Speakers Bureau; Curis, Inc: Research Funding; Xencor: Research Funding; Kite: Consultancy, Research Funding, Speakers Bureau; Genentech/Roche: Consultancy, Research Funding, Speakers Bureau; Juno Pharmaceuticals: Consultancy; Fate Therapeutics: Research Funding; Bristol Myers Squibb: Consultancy, Research Funding, Speakers Bureau; MEI Pharma: Consultancy, Research Funding; Trillium Therapeutics: Research Funding; BeiGene: Consultancy; Celgene: Consultancy, Research Funding, Speakers Bureau; Morphosys: Consultancy; Abbvie: Consultancy; Aptevo Therapeutics: Research Funding; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Sunesis Pharmaceuticals: Research Funding; Pharmacyclics/Janssen: Consultancy, Research Funding, Speakers Bureau; Velos Bio: Research Funding; Millenium/Takeda: Research Funding. Diefenbach: Celgene: Research Funding; Trillium: Research Funding; IMab: Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Incyte: Research Funding; Gilead: Current equity holder in publicly-traded company; AbbVie: Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; IGM Biosciences: Research Funding; MEI: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding. Alvarado: BerGenBio: Research Funding; MEI Pharma: Research Funding; CytomX Therapeutics: Consultancy; Astex Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Research Funding; Daiichi-Sankyo: Research Funding; FibroGen: Research Funding; Sun Pharma: Consultancy, Research Funding. Al Malki: Rigel Pharma: Consultancy; Neximmune: Consultancy; Jazz Pharmaceuticals, Inc.: Consultancy; Hansa Biopharma: Consultancy; CareDx: Consultancy. Danilov: Bayer Oncology: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; SecuraBio: Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding; Rigel Pharm: Honoraria; Bristol-Meyers-Squibb: Honoraria, Research Funding; Gilead Sciences: Research Funding; Pharmacyclics: Consultancy, Honoraria; Beigene: Consultancy, Honoraria. Abedin: Pfizer: Research Funding; Amgen: Honoraria; Helsinn: Research Funding; Astellas Pharma Inc.: Research Funding; Agios: Honoraria; Actinium: Research Funding; AltruBio: Research Funding. Ghalie: MEI Pharma: Current Employment, Current equity holder in publicly-traded company. Davids: Genentech: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; MEI Pharma: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Ascentage Pharma: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Surface Oncology: Research Funding; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; BeiGene: Consultancy; Celgene: Consultancy; Eli Lilly and Company: Consultancy; Janssen: Consultancy; MEI Pharma: Consultancy; Merck: Consultancy; Research to Practice: Consultancy; Takeda: Consultancy. OffLabel Disclosure: Vorucicilb is an investigational CDK inhibitor being evaluated in patients with hematologic malignancies, specifically relapsed AML and B-cell malignancies. The abstract submitted to ASH 2021 reports the results of the completed dose escalation portion of a phase 1 study.

AbstractStudy RationaleThe swift progression of the COVID‐19 pandemic appeared to facilitate the increase in telehealth utilization. However, it is clear neither how telehealth was offered by providers nor how it was used by patients during this time of unusual and rapid change within the health industry.AimTo investigates the telehealth utilization patterns of Medicare beneficiaries during the height of the COVID‐19 pandemic.Methods and MaterialsA cross‐sectional study design was used to examine the responses of 9686 Medicare beneficiaries to the Centers for Medicare and Medicaid Services (CMS) Medicare Current Beneficiary Survey, Fall 2020 COVID‐19 Supplement. Multiple logistic regression analyses were conducted to examine the relationship between telehealth offering and beneficiaries' sociodemographic variables.ResultsOver half (58%) of primary care providers provided telehealth services, while only 26%–28% of specialists did. Less than 8% of Medicare beneficiaries reported that they were unable to obtain care because of COVID‐19.ConclusionsThis research found that changes in Medicare policy, associated with CMS' declaration of telehealth waivers during the Public Health Emergency (PHE), likely increased the proliferation and utilization of telehealth services during the COVID‐19 pandemic, providing important access to care for certain populations. With the impending conclusion of the PHE, policymakers must 1) ascertain which elements of the new telehealth landscape will be retained, 2) modernize the regulatory, accreditation and reimbursement framework to maintain pace with care model innovation and 3) address disparities in access to broadband connectivity with a particular focus on rural and underserved communities.

Aims: The MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer-based atrial sensing. Data regarding the real-world experience with this novel system are currently lacking. We sought to characterize patients undergoing MicraTM -AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony. Methods: In this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM -AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow-up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous-ventricular pacing (AsVP) ≥70%. Results: Fifty-six percent of patients achieved AsVP ≥70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure and pulmonary hypertension. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were persistent atrial arrhythmias, small A4-wave amplitude, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow-up. Conclusion: With the increasing popularity of leadless PM, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM -AV devices.

AbstractBackgroundWhile ventricular tachycardia (VT) in the setting of postmyocardial infarction left ventricular aneurysms (LVA) is not uncommonly encountered, there is a scarcity of data regarding the safety, efficacy, and outcomes of ablation of VT in this subset of patients.MethodsOur study included consecutive patients aged 18 years or older with postmyocardial infarction LVA who presented to Mayo Clinic for catheter ablation of VT between 2002 and 2018.ResultsOf 34 patients, the mean age was 70.4 ± 9.1 years; 91% were male. Mean LVEF was 29 ± 9.7% and left ventricular end‐diastolic dimension was 64.9 ± 6.6 mm. The site of the LVA was apical in 21 patients (62%). Fifteen patients (44%) presented with electrical storm or incessant VT. Nine patients (26%) had a history of intracardiac thrombus. All except for one patient had at least one VT originating from the aneurysm. The mean number of VTs was 2.9 ± 1.7. All patients underwent ablation at the site of the aneurysm. Ablation outside the aneurysm was performed in 13 patients (38%). Low‐voltage fractionated potentials and/or late potentials at the aneurysmal site were present in all cases. Complete elimination of all VTs was achieved in 18 (53%), while the elimination of the clinical VT with continued inducibility of nonclinical VTs was achieved in a further 11 patients (32%). Two patients developed cardiac tamponade requiring pericardiocentesis. During a mean follow‐up period of 2.3 ± 2.4 years, 11 patients (32%) experienced VT recurrence. Freedom from all‐cause mortality at 1‐year follow‐up was 94%.ConclusionRadiofrequency catheter ablation targeting the aneurysmal site is a feasible and reasonably effective management strategy for clinical VTs in patients with postinfarction LVA.