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Background Mold-active primary antifungal prophylaxis (PAP) is routinely recommended in neutropenic patients with newly diagnosed acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) undergoing remission-induction chemotherapy (RIC). Isavuconazole (ISAV) is an extended spectrum mold-active triazole and has superior tolerability and fewer significant drug–drug interactions compared with other triazoles. Methods In our investigator-initiated, phase 2 trial, treatment-naive adult patients with AML or MDS starting RIC received ISAV per the dosing recommendations in the US label until neutrophil recovery (absolute neutrophil count [ANC] ≥ 0.5 × 109/L) and attainment of complete remission, occurrence of invasive fungal infection (IFI), or for a maximum of 12 weeks. The primary endpoint was the incidence of proven/probable IFI during ISAV PAP and up to 30 days after the last dose. Results Sixty-five of 75 enrolled patients received ISAV PAP (median age, 67 years, median ANC at enrollment, 0.72 × 109/L). Thirty-two patients (49%) received oral targeted leukemia treatments (venetoclax, FTL3 inhibitors). Including the 30-day follow-up period, probable/proven and possible IFIs were encountered in 4 (6%) and 8 patients (12%), respectively. ISAV trough serum concentrations were consistently > 1 µg/mL, showed low intraindividual variation, and were not significantly influenced by chemotherapy regimen. Tolerability of ISAV was excellent, with only 3 cases (5%) of mild to moderate elevations of liver function tests and no QTc prolongations. Conclusions ISAV is a safe and effective alternative for PAP in patients with newly diagnosed AML/MDS undergoing RIC in the era of recently approved or emerging small-molecule antileukemia therapies. Clinical Trials Registration NCT03019939.

Background: Philadelphia chromosome-positive (Ph+) advanced leukemias, including acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) in myeloid blast phase (MBP), have poor outcomes. Venetoclax has shown synergism with BCR-ABL1 tyrosine kinase inhibitors (TKI) in preclinical studies. However, clinical activity of venetoclax and TKI-based regimens is unknown. Methods: We conducted a retrospective study on patients with Ph+ AML (n = 7) and CML-MBP (n = 9) who received venetoclax combined with TKI-based regimens at our institution. Results: Median patient age was 42 years, and the median number of prior therapy cycles was 5 (range 2–8). Nine patients received decitabine-based, and 7 received intensive chemotherapy-based regimens. Ten patients (63%) received ponatinib. The overall response rate (ORR) in 15 evaluable patients was 60% (1 complete remission [CR], 6 CR with incomplete hematologic recovery [CRi], 1 morphologic leukemia-free state, and 1 partial response). The ORR was 43% in Ph+ AML and 75% in CML-MBP. The median overall survival (OS) for all patients was 3.6 months, for AML OS was 2.0 months, and for CML-MBP OS was 10.9 months. The median relapse-free survival for AML and CML-MBP was 3.6 and 3.9 months, respectively. Compared to nonresponders, patients achieving CR/CRi had higher baseline Ph+ metaphases and BCR-ABL1 PCR. Conclusions: Combination therapy of venetoclax with TKI-based regimens shows encouraging activity in very heavily pretreated, advanced Ph+ leukemias, particularly CML-MBP.

Background Venetoclax (VEN) in combination with a hypomethylating agent (HMA) has become the standard of care for patients aged >75 years and for those not eligible for intensive chemotherapy who have newly diagnosed acute myeloid leukemia (AML). The benefit of VEN-based therapy in patients who have newly diagnosed AML with mutations in the TP53 gene (TP53mut ) over standard therapy is undefined. Methods In this single-institutional, retrospective analysis, the authors assessed the clinical outcomes of 238 patients with newly diagnosed TP53mut AML and compared the clinical characteristics, response to different therapies, and outcomes of those who received VEN-based (n = 58) and non-VEN-based (n = 180) regimens. Results Patients who received VEN-based regimens were older (aged >65 years: 81% vs 65%; P = .02) and had higher response rates (complete remission, 43% vs 32%; P = .06) than those who received non-VEN-based regimens. Compared with patients who received non-VEN-based regimens, no difference in overall survival (median, 6.6 vs 5.7 months; P = .4) or relapse-free survival (median, 4.7 vs 3.5 months; P = .43) was observed in those who received VEN-based regimens, regardless of age or intensity of treatment. Conclusions The addition of VEN to standard treatment regimens did not improve outcomes in younger or older patients who had TP53mut AML. These data highlight the need for novel therapies beyond VEN to improve the outcome of patients with TP53mut AML.

Background Venetoclax (VEN) combined with the hypomethylating agent (HMA) azacitidine improves survival in patients aged ≥75 years with newly diagnosed acute myeloid leukemia (AML). VEN and HMA treatment can result in prolonged and often profound neutropenia, and this warrants antifungal prophylaxis. Azole antifungals inhibit cytochrome P450 3A4, the primary enzyme responsible for VEN metabolism; this results in VEN dose reductions for each concomitant antifungal. Limited clinical data exist on outcomes for patients treated with VEN, an HMA, and various azoles. Methods The time to neutrophil recovery (absolute neutrophil count [ANC] > 1000 cells/mm3 ) and platelet (PLT) recovery (PLT count > 100,000 cells/mm3 ) in 64 patients with newly diagnosed AML who achieved a response after course 1 of VEN plus an HMA were evaluated. HMA therapy included azacitidine (75 mg/m2 intravenously/subcutaneously for 7 days) or decitabine (20 mg/m2 intravenously for 5 or 10 days). Results Forty-seven patients (73%) received an azole: posaconazole (n = 17; 27%), voriconazole (n = 9; 14%), isavuconazole (n = 20; 31%), or fluconazole (n = 1; 2%). The median time to ANC recovery were similar for patients who did receive an azole (37 days; 95% confidence interval [CI], 34-38 days) and patients who did not receive an azole (39 days; 95% CI, 30 days to not estimable; P = .8). The median time to PLT recovery was significantly longer for patients receiving azoles (28 vs 22 days; P = .01). The median times to ANC recovery (35 vs 38 days) and PLT recovery (26 vs 32 days) were similar with posaconazole and voriconazole. Conclusions VEN plus an HMA resulted in neutropenia and thrombocytopenia, with the latter prolonged in patients receiving concomitant azoles. Concomitant posaconazole or voriconazole and VEN (100 mg) resulted in similar ANC and PLT recovery times, suggesting the safety of these dosage combinations during course 1.

Background: Patients with a history of bariatric surgery are often excluded from clinical trials evaluating oral therapies. This is due to concerns that these surgeries alter bioavailability and drug metabolism. Oral tyrosine kinase inhibitors (TKIs) are the mainstay treatment for chronic myeloid leukemia (CML). However, the impact of bariatric surgeries on CML treatment outcomes is largely unknown. Methods: In a retrospective analysis, we screened patients with CML treated at our institution and identified those who had any type of bariatric surgery including gastric bypass, gastric sleeve surgery or gastric banding. Subsequently, we compared their responses and outcomes to a control cohort of patients without history of bariatric surgery, using propensity score matching for Sokal Risk and body mass index (BMI) at a 2:1 ratio. In addition to cytogenetic and molecular responses, we assessed times to achieving responses and BCR-ABL1 halving times to investigate differences in response dynamics (Branford, Blood 2014). Event-free survival (EFS) was measured from treatment start to loss of response, progression or death, whereas failure-free survival (FFS) additionally accounted for therapy discontinuation for any other reason such as intolerance. Overall survival (OS) was measured from treatment start date to death, or censored at last follow-up. Univariate and multivariate analyses (MVA) were used to assess the association between characteristics and overall survival. Results: We identified 28 patients with CML and bariatric surgery, of whom 22 (79%) had their surgery before CML. Their baseline characteristics are summarized below (Figure 1). Despite propensity score matching, patients with bariatric surgery compared to control had a higher BMI at time of CML diagnosis (median: 38 vs 26 Kg/m 2, P Patients with history of bariatric surgery received a higher number of TKIs throughout their CML treatment because of resistance or intolerance compared to control (median of 2, range 1-6 vs median of 1, range 1-3, P Patients with bariatric surgery and CML had inferior EFS compared to control (5-year EFS rate: 61% vs 87% respectively, P=0.0003) and inferior FFS (5-year FFS rate: 15% vs 77% respectively, P Conclusion: Bariatric surgery is associated with slower responses to TKIs in patients with CML, and a lower chance of deep remission. It is also associated with higher rates of treatment failure and worse overall survival. There is an unmet need to design treatment strategies for these patients. Although not readily available in the clinical setting, studies measuring drug level in these patients are needed to assess which TKI has a better bioavailability, which in turn could translate to improved outcomes. Figure 1 Figure 1. Disclosures Kantarjian: Aptitude Health: Honoraria; BMS: Research Funding; Astellas Health: Honoraria; Jazz: Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Immunogen: Research Funding; KAHR Medical Ltd: Honoraria; Ascentage: Research Funding; AbbVie: Honoraria, Research Funding; NOVA Research: Honoraria; Daiichi-Sankyo: Research Funding; Amgen: Honoraria, Research Funding; Astra Zeneca: Honoraria; Ipsen Pharmaceuticals: Honoraria; Precision Biosciences: Honoraria; Taiho Pharmaceutical Canada: Honoraria. Jabbour: Amgen, AbbVie, Spectrum, BMS, Takeda, Pfizer, Adaptive, Genentech: Research Funding. Short: Takeda Oncology: Consultancy, Research Funding; NGMBio: Consultancy; AstraZeneca: Consultancy; Astellas: Research Funding; Novartis: Honoraria; Jazz Pharmaceuticals: Consultancy; Amgen: Consultancy, Honoraria. Pemmaraju: Roche Diagnostics: Consultancy; Dan's House of Hope: Membership on an entity's Board of Directors or advisory committees; Sager Strong Foundation: Other; ASCO Leukemia Advisory Panel: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Consultancy, Other: Research Support, Research Funding; Plexxicon: Other, Research Funding; HemOnc Times/Oncology Times: Membership on an entity's Board of Directors or advisory committees; Samus: Other, Research Funding; Celgene Corporation: Consultancy; Stemline Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Clearview Healthcare Partners: Consultancy; Protagonist Therapeutics, Inc.: Consultancy; Incyte: Consultancy; Abbvie Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; ASH Communications Committee: Membership on an entity's Board of Directors or advisory committees; Affymetrix: Consultancy, Research Funding; Cellectis S.A. ADR: Other, Research Funding; CareDx, Inc.: Consultancy; Daiichi Sankyo, Inc.: Other, Research Funding; Blueprint Medicines: Consultancy; LFB Biotechnologies: Consultancy; Aptitude Health: Consultancy; Springer Science + Business Media: Other; DAVA Oncology: Consultancy; MustangBio: Consultancy, Other; Bristol-Myers Squibb Co.: Consultancy; ImmunoGen, Inc: Consultancy; Pacylex Pharmaceuticals: Consultancy. Ravandi: Amgen: Honoraria, Research Funding; Xencor: Honoraria, Research Funding; AstraZeneca: Honoraria; Novartis: Honoraria; AbbVie: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Taiho: Honoraria, Research Funding; Syros Pharmaceuticals: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Prelude: Research Funding; Agios: Honoraria, Research Funding; Jazz: Honoraria, Research Funding. Sasaki: Pfizer: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding. Issa: Novartis: Consultancy, Research Funding; Syndax Pharmaceuticals: Research Funding; Kura Oncology: Consultancy, Research Funding.

Introduction: A first-in-class anticancer quinolone derivative with topoisomerase II activity, mechanistically, vosaroxin is similar to the anthracycline class. However, vosaroxin displays advantageous pharmacokinetic properties such as minimal metabolism, a lack of free radical production, is not a substrate for the P glycoprotein efflux pump, and can exert its antineoplastic activity independently of P53 function. Vosaroxin has shown encouraging results when combined with cytarabine in older patients with relapsed or refractory acute myeloid leukemia (AML) while balancing early toxicity and mortality, making it a compelling novel therapy for acute myelogenous leukemia.Areas covered: Herein, we review the clinical data from published and internationally presented clinical trials utilizing vosaroxin for AML in the elderly, and relapsed and refractory population. Pivotal trials reviewed include the multicenter, phase II, REVEAL-1 study of single-agent vosaroxin in untreated elderly patients and the...

Background Coagulase-negative staphylococci, including Staphylococcus epidermidis, are the most common cause of bloodstream infection in cancer patients. Linezolid resistance is increasingly identified in S. epidermidis, but whether such resistance alters the clinical course of S. epidermidis infections is unknown. The purpose of this study was to assess the clinical impact of linezolid resistance in leukemia patients with S. epidermidis bloodstream infection. Methods This was a retrospective, single-center cohort study of all adult leukemia patients with S. epidermidis bacteremia treated with empiric linezolid between 2012 and 2015. The primary end point was adverse clinical outcome on day 3, defined as a composite of persistent bacteremia, fever, intensive care unit admission, or death. Fourteen- and 30-day mortality were also assessed. Results Eighty-two unique leukemia patients with S. epidermidis were identified. Linezolid resistance was identified in 33/82 (40%). Patients with linezolid-resistant S. epidermidis were significantly more likely to have persistent bacteremia (41% vs 7%; adjusted relative risk [aRR], 5.15; 95% confidence interval [CI], 1.63–16.30; P = .005); however, adverse short-term clinical outcomes overall were not more common among patients with linezolid-resistant S. epidermidis (61% vs 33%; aRR, 1.46; 95% CI, 0.92–2.32; P = .108). No differences were observed in 14- or 30-day mortality. Conclusions Leukemia patients with linezolid-resistant S. epidermidis bacteremia who were treated with linezolid were significantly more likely to have persistent bacteremia compared with those with linezolid-sensitive isolates. Interventions to limit the clinical impact of linezolid-resistant S. epidermidis are warranted.

Introduction Venetoclax (VEN), a selective BCL2 inhibitor, has single-agent activity in relapsed and refractory (R/R) acute myeloid leukemia (AML), and efficacy in lower intensity combinations for treatment-naive elderly AML patients. VEN treatment combinations in R/R AML have not been previously reported. Methods All R/R myeloid patients (including AML, myelodysplastic syndrome (MDS), and blastic plasmacytoid dendritic cell neoplasm (BPDCN)) treated with VEN combinations in the salvage setting were reviewed. Results Forty-three patients with median age 68 (range, 25-83) were treated for AML (91%), MDS (5%), or BPDCN (5%). Most (n = 36, 84%) were ≥ salvage-2 treatment status, including prior hypomethylating agent (HMA) in 77%. In combination with VEN, most patients received HMA therapy (n = 31, 72%); eight (19%) received low-dose cytarabine (LDAC). Patients received a median of 2 treatment cycles (range, 1-4). Objective response was observed in 9 (21%) patients, including 2 complete responses (CR), 3 CRi, and 4 morphologic leukemia-free state (MLFS). Median survival was 3.0 months (range, 0.5-8.0), and estimated 6-month survival was 24%. Responses were observed in five (24%) of 21 patients with intermediate-risk cytogenetics, 3 (27%) of 11 IDH1/2-mutant, and 4 (50%) of 8 RUNX1-mutated patients. Two (20%) of 10 TP53-mutated patients responded; both had concurrent RUNX1 mutations. Of the 3 (15%) responding patients with adverse cytogenetics, all had concurrent RUNX1 mutations. Conclusion Low-intensity chemotherapy, including HMAs or LDAC, in combination with VEN is a viable salvage option, even in multiply relapsed/refractory patients with AML, MDS, and BPDCN. Notable responses were identified in patients with diploid/intermediate cytogenetics, RUNX1, and/or IDH1/2 mutations.

Introduction: Venetoclax (VEN) is approved for the treatment of acute myeloid leukemia (AML) in combination with hypomethylating agents (HMAs) or low-dose cytarabine and commonly used for patients (pts) unfit for intensive chemotherapy. Prophylaxis with triazole antifungals (azoles) during induction treatment in pts with AML has decreased mortality and is the standard of care for pts receiving treatment regimens associated with prolonged myelosuppression (Cornely et al, 2007). Azoles inhibit CYP3A4 (CYP3A4i), the enzyme responsible for the metabolism of VEN, and p-glycoprotein to varying degrees, which VEN is a substrate. Based on this interaction and the results of a small pharmacokinetic study, significant VEN dosage reductions are recommended (Agarwal et al, 2017). Little real-world data exists to demonstrate the tolerability of VEN in combination with azoles during induction treatment with VEN and HMAs. Methods: All pts with newly diagnosed AML treated at our institution with VEN and HMAs from 11/2014-1/2019 were retrospectively reviewed. Pts were treated as standard of care or as part of clinical trial in combination with azacitidine (NCT02203773) or decitabine (NCT03404193; NCT02203773). Pts who received concomitant antifungal for >5 days while also receiving VEN for >7 days were included. VEN 100mg daily with posaconazole or voriconazole (strong CYP3A4i) and VEN 200mg daily with isavuconazole or fluconazole (moderate CYP3A4i) were considered 400mg equivalent dosages. Higher doses of VEN in these combinations were considered >VEN 400mg equivalent. To determine the clinical impact of concomitant azoles, time to absolute neutrophil count (ANC) and platelet (PLT) recovery after induction was analyzed, in addition to response rates, episodes of febrile neutropenia (FN) and documented infections. Results:One-hundred twenty-one pts treated with HMA and VEN were identified (Table 1). The median age was 72 years (48-86) and 35% were > 75 years. Forty pts (33%) had secondary AML, and 10% had therapy-related AML. Most were treated with decitabine 20mg/m2 administered for 10 days (67%) or 5 (22%). VEN was administered for a median of 23 days (7-30) at a 400mg daily dose equivalent in 74 pts (62%) and >400mg dose equivalent in 40 pts (33%). Eighty-nine (74%) received a concomitant azole with VEN including posaconazole (38%), isavuconazole (21%), voriconazole (13%), or fluconazole (2%). Following induction therapy with VEN and HMA, 37% achieved a complete response (CR) and 22% achieved a CR with incomplete blood count recovery (CRi). An additional 10% achieved a morphologic leukemia free state (MLFS) (Table 2). Prior to cycle 2, 55% of pts achieved ANC>500 cells/mm3 and 64% achieved PLT>50,000 cells/mm3 after a median of 34 days and 24 days, respectively. No difference in response was observed based on VEN dosage or duration (Table 3). Pts achieving CR/CRi received VEN for a median of 22 days (7-29), and 38% at the 400mg equivalent VEN dosage with an azole. When analyzing VEN dosage by the use of an azole, duration of neutropenia (ANC0.05) (Table 4). Number of pts achieving PLT>50,000 cells/mm3 was not affected by concomitant antifungal or VEN dosage, but duration of thrombocytopenia was. Time to PLT>50,000 cells/mm3 was significantly longer for pts receiving VEN 400mg equivalent with an azole (25 vs 20 days, p=0.01) as well as time to PLT>100,000 cells/mm3 (27 vs 22 days, p=0.03). Despite prolonged cytopenias, all pts receiving the VEN 400mg equivalent dosage had similar rates of FN, documented infections, and hospital duration regardless of the use of an azole (Table 4). Those receiving >400mg VEN equivalent had numerically higher rates of FN, infections, and duration of hospitalization. Conclusion: The combination of VEN with HMA is an effective treatment option in pts with newly diagnosed AML. VEN is associated with significant myelosuppression which can be enhanced by concomitant CYP3A4i, such as the azoles. The combination of VEN and azoles resulted in prolonged cytopenias, namely thrombocytopenia, compared to the use of VEN without an azole. This did not result in higher rates of FN, infections, or duration of hospitalization, therefore the concomitant use of VEN and azole appear to provide a clinically safe and effective therapeutic regimen. Higher doses of VEN do not appear to be advantageous in this setting. Disclosures DiNardo: daiichi sankyo: Honoraria; jazz: Honoraria; syros: Honoraria; medimmune: Honoraria; notable labs: Membership on an entity's Board of Directors or advisory committees; abbvie: Consultancy, Honoraria; agios: Consultancy, Honoraria; celgene: Consultancy, Honoraria. Maiti:Celgene: Other: research funding. Kadia:Celgene: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioline RX: Research Funding; BMS: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Research Funding. Borthakur:Polaris: Research Funding; Strategia Therapeutics: Research Funding; Tetralogic Pharmaceuticals: Research Funding; FTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Xbiotech USA: Research Funding; Bayer Healthcare AG: Research Funding; AstraZeneca: Research Funding; BMS: Research Funding; Eli Lilly and Co.: Research Funding; Oncoceutics, Inc.: Research Funding; PTC Therapeutics: Consultancy; NKarta: Consultancy; BioLine Rx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cyclacel: Research Funding; GSK: Research Funding; Janssen: Research Funding; Incyte: Research Funding; AbbVie: Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; Eisai: Research Funding; Novartis: Research Funding; Cantargia AB: Research Funding; Arvinas: Research Funding; Oncoceutics: Research Funding; BioTheryX: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Agensys: Research Funding. Pemmaraju:affymetrix: Research Funding; sagerstrong: Research Funding; Daiichi-Sankyo: Research Funding; plexxikon: Research Funding; novartis: Consultancy, Research Funding; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; cellectis: Research Funding; celgene: Consultancy, Honoraria; samus: Research Funding; abbvie: Consultancy, Honoraria, Research Funding; mustangbio: Consultancy, Research Funding; incyte: Consultancy, Research Funding. Sasaki:Pfizer: Consultancy; Otsuka: Honoraria. Ravandi:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Menarini Ricerche: Research Funding; Cyclacel LTD: Research Funding; Selvita: Research Funding; Xencor: Consultancy, Research Funding; Macrogenix: Consultancy, Research Funding. Kantarjian:Astex: Research Funding; AbbVie: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Immunogen: Research Funding; Takeda: Honoraria; Agios: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; BMS: Research Funding; Cyclacel: Research Funding; Daiichi-Sankyo: Research Funding; Novartis: Research Funding; Jazz Pharma: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Research Funding. Konopleva:Astra Zeneca: Research Funding; Reata Pharmaceuticals: Equity Ownership, Patents & Royalties; Ablynx: Research Funding; Agios: Research Funding; Kisoji: Consultancy, Honoraria; Ascentage: Research Funding; Calithera: Research Funding; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; Genentech: Honoraria, Research Funding; Forty-Seven: Consultancy, Honoraria; F. Hoffman La-Roche: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Cellectis: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Eli Lilly: Research Funding.

Introduction: The addition of tyrosine kinase inhibitors to hyperfractionated cyclophosphamide, dexamethasone, vincristine, and doxorubicin alternating with high-dose methotrexate and cytarabine (HCVAD) for the treatment of Ph-positive ALL has significantly improved outcomes. However, with the increased median survival, an increased incidence of CNS relapses were documented over time, thus suggesting an increased risk among pts with Ph-positive disease (Ravandi et al, Cancer 2015).In order to reduce this incidence, treatment protocols for Ph-positive ALL were amended in 2012 to increase prophylactic IT chemotherapy from 8 to 12 at our institution. The aim of this study is to compare the incidence of CNS relapses in pts with Ph-positive ALL treated with 8 versus 12 ITs. Methods: We conducted a retrospective chart review of 156 pts with newly diagnosed Ph-positive ALL treated with Rituximab (R)± HCVAD plus imatinib (n=35), dasatinib (n=68), or ponatinib (n=53) between July 2001 and January 2019. Pts with CNS disease at initial diagnosis were excluded. Complete molecular response (CMR) at 3 months was defined as absence of a quantifiable BCR-ABL1 transcript. CNS relapse was identified by detection of blasts or rare atypical cells in the cerebrospinal fluid (CSF) in at least 2 successive evaluations and/or findings of leptomeningeal disease on imaging. Landmark analysis was performed at 6 months at the approximate time of completion of both systemic and IT therapy. Poor risk cytogenetic abnormality was defined as the presence of +der(22)t(9;22) and/or −9/9p in the absence of high hyperdiploidy (51‐65 chromosomes). CNS relapse-free survival (RFS) was defined from the start of therapy to the time of CNS relapse. Patients who died or relapsed in bone marrow were censored at the time of death and systemic relapse, respectively. Survival was assessed with and without the censoring of allogeneic stem cell transplantation (ASCT). Results: Pt characteristics are summarized in Figure A. One hundred and twelve pts (72%) received a median of 8 ITs (range, 2-8) and 44 pts (28%) received a median of 12 (range, 9-15). There were no statistically significant differences between groups in regards to baseline characteristics with the exception that more patients in the > 8 ITs cohort received ponatinib (66% vs 21%) and thus achieved a higher rate of 3-month CMR (70% vs 52%; p=0.04). CNS relapses were identified in 11 pts overall (7%, 4 treated with imatinib and 7 with dasatinib) and all of them received 8 or less prophylactic ITs (IT ≤8, 10% vs IT >8, 0%; p=0.023). The median follow-up of the entire population was 81 months, and 97 and 43 months for pts who received ≤8 and >8 ITs, respectively. The 3 and 6-year CNS RFS was 89% and 88% in pts with ≤8 ITs and 100% in pts with >8 Its, respectively (overall P=0.041; 3-yr CNS RFS P=0.049; 6-yr CNS RFS P=0.045) (Figure B). The outcomes remained statistically significant even after censoring for ASCT (P=0.048) (Figure C). In a multivariate analysis and after adjusting for the follow-up time, a median of 12 prophylactic IT chemotherapies was a prognostic factor significantly associated with a decrease rate of CNS relapses (P=0.03; HR=0.64 95%, CI: 0.43-0.96) (Figure D). Conclusion: In pts with newly diagnosed Ph-positive ALL, incorporation of 12 prophylactic IT chemotherapy in addition to systemic therapy is a very effective strategy to reduce the long-term incidence of CNS relapses. Figure Disclosures Paul: Pfizer: Consultancy; Agios: Consultancy. Sasaki:Otsuka: Honoraria; Pfizer: Consultancy. Kadia:BMS: Research Funding; Jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioline RX: Research Funding; Celgene: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Research Funding. Garcia-Manero:Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Amphivena: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Ravandi:Macrogenix: Consultancy, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Xencor: Consultancy, Research Funding; Menarini Ricerche: Research Funding; Selvita: Research Funding; Cyclacel LTD: Research Funding. Kantarjian:BMS: Research Funding; Novartis: Research Funding; AbbVie: Honoraria, Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Research Funding; Daiichi-Sankyo: Research Funding; Takeda: Honoraria; Pfizer: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Astex: Research Funding; Jazz Pharma: Research Funding; Cyclacel: Research Funding; Immunogen: Research Funding; Amgen: Honoraria, Research Funding. Jabbour:AbbVie: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Cyclacel LTD: Research Funding; Pfizer: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Adaptive: Consultancy, Research Funding.

Background Fluoroquinolones (FQs) are routinely used as antimicrobial prophylaxis in leukemia patients receiving chemotherapy to prevent Pseudomonas aeruginosa infections. Patients who are intolerant to FQs may receive cefpodoxime (CPD) or other agents. How FQ use affects the resistance profile and epidemiology of breakthrough P. aeruginosa infections is unknown. To determine this, we performed a whole-genome sequencing (WGS)-driven epidemiologic study of leukemia patients with P. aeruginosa bloodstream infections. Methods All adult (age > 17 years) inpatients with leukemia and a first episode of monomicrobial P. aeruginosa bloodstream infection were included. Clinical data were extracted from the electronic medical record. Isolates were sequenced using an Illumina NextSeq and phylogenomics was performed using an in-house analysis pipeline consisting of Bowtie2, SAMtools and bcftools. Results 110 patients were included and most had a diagnosis of acute myeloid leukemia (n = 66). Twenty (18%) patients received FQ prophylaxis, 56 (54%) received CPD, and the remaining 34 (31%) received other agents. 9 (8%) isolates were multidrug-resistant (MDR). MDR was more common in those receiving FQ prophylaxis (20% vs 6%, P = 0.06). 76 sequence types (STs) were represented with ST235 (n = 8) being most common followed by ST244 (n = 7). ST235 strains were genetically distinct, but closely related (>10 but < 250 SNPs) in comparison to other STs. 2 ST244 strains were genetically identical despite being isolated 4 months apart, suggesting horizontal transmission. MDR was more common among ST235 isolates compared with other STs (38% vs 6%, P = 0.02). ST235 strains were more common in patients receiving FQ vs other prophylaxis (20% vs 4%, P = 0.04). 1 ST244 isolate harbored a VIM-2 β-lactamase. In 20 FQ-resistant isolates, 80% had mutations in either parC (S87L) or gyrA (T83I) and 50% had both. FQ-resistance mutations were more common in FQ recipients (50% vs 8%, P < 0.01). Conclusion Most P. aeruginosa infections occurred in non-FQ recipients, while MDR P. aeruginosa infections were more common in FQ recipients. These data suggest that decisions on empiric treatment of patients with P. aeruginosa bacteremia must take antimicrobial prophylaxis history into account. Disclosures Samuel L. Aitken, PharmD, Melinta Therapeutoics: Grant/Research Support, Research Grant; Merck, Sharpe, and Dohme: Advisory Board; Shionogi: Advisory Board.

Background Mold-active antifungal prophylaxis (ppx) is recommended in neutropenic patients with newly diagnosed AML or MDS. ISAV is an extended spectrum triazole with superior tolerability, reliability of absorption, fewer drug–drug interactions, lack of QTc prolongation or need for therapeutic drug monitoring, approved for the treatment of invasive aspergillosis (IA) and mucormycosis. NCT03019939 is an investigator-initiated, phase 2 trial of PAP with ISAV in patients with AML/MDS. Methods Treatment-naïve adult patients with AML or MDS initiating remission-induction chemotherapy (RIC) received ISAV per the dosing recommendations in the United States label until recovery from neutropenia (neutrophils (ANC) ≥ 0.5 × 109/L) and attainment of complete remission (CR), occurrence of proven or probable invasive fungal infection (IFI, EORTC/MSG criteria), or for a maximum of 12 weeks. The primary endpoint was incidence of proven/probable IFI during the study period (up to 30 days from the last dose of ISAV). Results 67 patients were enrolled (April 28, 2017 to February 14, 2019) and 60 patients were eligible for assessment (median age 67 years, 57 patients with AML, median ANC on enrollment was 660). Reasons for study completion were achievement of CR with ANC recovery (n = 35), completion of 12 weeks of PAP (n = 9), possible IFI (n = 7), investigator decision (n = 3), death (n = 2, 1 disease progression, 1 cardiac arrest), proven/probable IFI (n = 3), and mild transaminitis, possibly ISAV-related (n = 2). The median durations of neutropenia and ISAV ppx were 33 (7–86) and 31 (7–86) days, respectively. One microbiologically-proven (gluteal abscess due to Candida glabrata) and 2 cases of probable breakthrough IFIs (probable IA with positive galactomannan) occurred (IFI incidence 5%). ISAV trough serum concentrations were available in 31 patients on both day 8 (median 3.74 µg/mL, 2.03–7.65) and day 15 (median 4.10 µg/mL, 2.17–9.25), and were not significantly different. Conclusion ISAV is a safe and effective alternative for PAP in patients with newly diagnosed AML/MDS undergoing RIC, with a breakthrough (proven/probable) IFI rate of 5%. ISAV serum levels were adequate in patients with AML/MDS undergoing RIC. Pharmacological features make ISAV attractive for PAP in the era of recently approved or emerging small-molecule AML therapies. Disclosures All authors: No reported disclosures.

Introduction: Invasive fungal infections (IFIs) are important causes of morbidity and mortality among patients (pts) with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), and consensus guidelines recommend the use of mold-active antifungal prophylaxis (ppx), e.g., voriconazole (vori) or posaconazole (posa). Isavuconazole (ISAV), the most recently introduced triazole antifungal, is currently approved for the treatment of invasive aspergillosis and invasive mucormycosis. ISAV is an appealing option for ppx against IFIs in neutropenic pts with AML/MDS because of its extended spectrum, superior tolerability (over vori), fewer drug-drug interactions (than posa), absence of need for therapeutic drug monitoring (TDM) and lack of prolongation of the QT interval (enabling easier administration in pts receiving certain anti-leukemic targeted therapies, 5-HT3 antagonists, quinolones, etc). NCT03019939 is an investigator-initiated, phase 2, single-arm, open-label trial of primary antifungal ppx with ISAV in pts with AML/MDS. Methods: Previously untreated adult pts with AML or MDS who are or are anticipated to become neutropenic as a result of their first therapy for AML/MDS are eligible to participate in this ongoing trial. Accrual of 100 pts is planned. Stopping rules exist for both futility and toxicity, assuming equivalence between ISAV and the current standard of care, posa, in preventing breakthrough IFIs (expected rate, 5%). In pts who have begun definitive anti-leukemic treatment, ISAV must be initiated within 4 days. Use of systemic antifungal therapy for >72 hours during the week prior to ISAV initiation is not allowed. ISAV is administered orally as the pro-drug, isavuconazonium sulfate, and dosed per the US label. ISAV ppx is administered until recovery from neutropenia (absolute neutrophil count (ANC) ≥0.5 x 109/L and attainment of complete remission (CR), with or without complete count recovery, occurrence of a proven or probable IFI (per 2008 EORTC/MSG criteria), development of unacceptable toxicity, pt withdrawal or death, or for a maximum of 12 weeks. The primary endpoint is the incidence of proven/probable IFI during the study period (up to 30 days from the last dose of ISAV). ISAV plasma concentrations are determined immediately pre-dose on days 8 and 15 using a validated assay. Results: A total of 50 pts were enrolled between April 28, 2017 and July 10, 2018. Four pts did not begin ppx with ISAV (1 each could not complete caspofungin washout and screening tests in time, 2 insurance denials). Of the remaining 46 pts (Table 1), 2 remain on study. Reasons for going off study (n = 44) included achievement of CR with neutrophil recovery (n = 26), completion of 12 weeks of therapy (n = 7), possible IFI (n = 5), investigator decision (n = 2), death (n = 2, 1 disease progression, 1 cardiac arrest), probable IFI (n = 1) and transaminitis (n = 1). In these 44 pts, the median duration of ISAV ppx was 30 (10-86) days. Only 1 case of proven breakthrough IFI occurred: a gluteal abscess that later grew Candida glabrata in a pt who had come off study upon achievement of CR. One case of probable IFI (focal mass-like opacity with ground-glass halo on CT; elevated Aspergillus antigen in broncho-alveolar lavage (BAL) fluid) occurred. All 5 cases of possible IFI were based on pulmonary radiologic findings alone: lower respiratory fungal cultures remained negative at 4 weeks in all 5 pts, and galactomannan was not detected in serum or BAL fluid in any pt. Tolerability of ISAV was excellent, with mild transaminitis attributed to ISAV reported in 1 pt (2%). No pt experienced QTc prolongation while on ISAV. Plasma ISAV levels were measured in 62 blood samples from 34 individual pts, including 28 paired samples. Median (range) ISAV concentrations were 3.74 (2.03-7.65) and 4.1 (2.17-9.25) mcg/ml on days 8 and 15, respectively. There was no correlation between plasma ISAV concentrations (available in 4 of the 7 pts) and the occurrence of confirmed, probable or possible IFI. Conclusions: These results demonstrate ISAV to be a safe and effective alternative for antifungal ppx in treatment-naïve pts with AML/MDS undergoing induction therapy with a variety of different regimens. ISAV's weak inhibition of P-glycoprotein and lack of risk of QT prolongation may make ISAV particularly attractive for antifungal ppx in the era of recently approved or emerging AML therapies such as enasidenib, ivosidenib, midostaurin and quizartinib. Disclosures Bose: CTI BioPharma: Research Funding; Constellation Pharmaceuticals: Research Funding; Blueprint Medicines Corporation: Research Funding; Celgene Corporation: Honoraria, Research Funding; Incyte Corporation: Honoraria, Research Funding; Astellas Pharmaceuticals: Research Funding; Pfizer, Inc.: Research Funding. Wiederhold:Astellas Pharmaceuticals: Research Funding. Kadia:Celgene: Research Funding; Amgen: Consultancy, Research Funding; Jazz: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Consultancy; Abbvie: Consultancy; Abbvie: Consultancy; BMS: Research Funding; Pfizer: Consultancy, Research Funding; BMS: Research Funding; Novartis: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy; Celgene: Research Funding; Takeda: Consultancy; Jazz: Consultancy, Research Funding. Ravandi:Abbvie: Research Funding; Xencor: Research Funding; Xencor: Research Funding; Jazz: Honoraria; Orsenix: Honoraria; Jazz: Honoraria; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Abbvie: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Sunesis: Honoraria; Bristol-Myers Squibb: Research Funding; Sunesis: Honoraria; Astellas Pharmaceuticals: Consultancy, Honoraria; Astellas Pharmaceuticals: Consultancy, Honoraria; Seattle Genetics: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Macrogenix: Honoraria, Research Funding; Macrogenix: Honoraria, Research Funding; Orsenix: Honoraria. Thompson:Gilead Sciences: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Research Funding; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Pemmaraju:celgene: Consultancy, Honoraria; abbvie: Research Funding; SagerStrong Foundation: Research Funding; cellectis: Research Funding; samus: Research Funding; stemline: Consultancy, Honoraria, Research Funding; daiichi sankyo: Research Funding; novartis: Research Funding; plexxikon: Research Funding; Affymetrix: Research Funding. Daver:Sunesis: Consultancy; Otsuka: Consultancy; Incyte: Research Funding; BMS: Research Funding; Karyopharm: Research Funding; Daiichi-Sankyo: Research Funding; Kiromic: Research Funding; ARIAD: Research Funding; Incyte: Consultancy; Karyopharm: Consultancy; Pfizer: Research Funding; Sunesis: Research Funding; ImmunoGen: Consultancy; Novartis: Consultancy; Alexion: Consultancy; Novartis: Research Funding; Pfizer: Consultancy. Cortes:Arog: Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding. Verstovsek:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees; Italfarmaco: Membership on an entity's Board of Directors or advisory committees. Konopleva:Stemline Therapeutics: Research Funding. Jain:Verastem: Research Funding; Astra Zeneca: Research Funding; Celgene: Research Funding; Celgene: Research Funding; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Genentech: Research Funding; Seattle Genetics: Research Funding; Adaptive Biotechnologioes: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Astra Zeneca: Research Funding; Genentech: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Research Funding; Cellectis: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Incyte: Research Funding; Infinity: Research Funding; Pfizer: Research Funding; ADC Therapeutics: Research Funding; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Research Funding; Adaptive Biotechnologioes: Research Funding; Infinity: Research Funding; BMS: Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Cellectis: Research Funding; Abbvie: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. DiNardo:Karyopharm: Other: Advisory role; Medimmune: Other: Advisory role; Celgene: Other: Advisory role; Bayer: Other: Advisory role; Agios: Consultancy, Other: Advisory role; AbbVie: Consultancy, Other: Advisory role. Wierda:Genentech: Research Funding; AbbVie, Inc: Research Funding. Sasaki:Otsuka Pharmaceutical: Honoraria. Kontoyiannis:Astellas Pharmaceuticals: Research Funding.

Background Patients undergoing chemotherapy for leukemia are at high risk for infection and routinely receive antibiotic prophylaxis. The types of breakthrough bloodstream infection (BSI) based on choice of prophylaxis is not well-characterized. Here, we describe antibiotic prophylaxis patterns and the influence of antibiotic choice on BSI epidemiology in leukemia patients presenting to the emergency center (EC) with neutropenic fever (NF). Methods This was a retrospective chart review of patients with leukemia and NF (absolute neutrophil count [ANC] 7 days in duration and the median ANC at presentation was 0 cells/mm3 (range: 0–490 cells/mm3). Most patients received LEV (42%) followed by CIP (27%), CEF (25%), and ACL (6%). Forty-seven of 284 patients presented with Gram-negative BSI (16%) and 36 (13%) had Gram-positive BSI. Rates of common organisms causing BSI are presented in Table 1. Conclusion In leukemia patients with NF presenting to the EC, rates of BSI differed significantly based on antibiotic prophylaxis choice, with P. aeruginosa BSI more common in patients receiving ACL and E. coli in patients receiving LEV. The epidemiology of breakthrough infections on different prophylactic agents may help guide empiric antibiotic choice. Table 1. Causative organisms of BSI. BSI Type LEV (n = 118) CIP (n = 77) CEF (n = 72) ACL (n = 17) P-value Any Gram-negative (n = 47) 21 (18) 7 (9) 13 (18) 6 (35) 0.05 E. coli (n = 25) 18 (15) 3 (4) 3 (4) 1 (6) 0.02 P. aeruginosa (n = 13) 2 (2) 1 (1) 6 (8) 4 (24)

Pediatric patients have traditionally been referred to as “therapeutic orphans” due to the lack of efficacy, safety, and dosing information provided for this population in the labeling of currently approved medications. Only 30–40% of medications with labeling approved by FDA have an