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Abstract Abstract 677 Background: Activating mutations of NRAS and KRAS (‘RAS’) are found in 10–30% of myeloid malignancies. Evidence of constitutive activation of the RAS-RAF-MEK-ERK pathway, however, is more ubiquitous. Trametinib is a potent, selective, allosteric inhibitor of MEK1/2 that inhibits proliferation of myeloid cell lines in vitro. A Phase I/II study of single, daily, oral dosing of trametinib in myeloid malignancies is ongoing. Here we report the results from Phase I/II patients receiving the recommended Phase II dose (RP2D) of 2 mg. Methods: Patient eligibility was limited to patients with relapsed/refractory myeloid malignancies and adequate hepatic, renal and cardiac function. There were no hematologic eligibility criteria. Patients were prospectively screened for KRAS mutations at amino acids 12, 13 and for NRAS mutations at amino acids 12, 13 and 61. Clinical response was assessed using International Working Group (2003 and 2006) criteria for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), respectively. Pharmacodynamic marker (pERK) analysis was conducted in phase II patients with patient paired (pre/during treatment) blood and bone marrow samples. Results: Eighty-seven (9 in Phase I and 78 in Phase II) patients received 2 mg of trametinib daily: AML (n=66), MDS (n=11), chronic myelomonocytic leukemia (CMML) (n=7) or other (n=3) (RAS mutations, n=57; RAS wild type, n=15 and RAS unknown, n=15). Median age was 68 years (range 21–87) and for close to half of the patients, trametinib was 3 3rd line of therapy. Trametinib exhibited a long effective half-life with small peak/trough ratios, and the exposure profile maintained time above preclinical target threshold for the 24-hour dosing period. Results of the pharmacodynamic analysis indicated an on-target effect of trametinib. Responses by RAS mutation status for Phase I/II subjects are summarized in Table 1. Responding patients have continued therapy for median of 16.9 weeks (range, 10.9 – 36.7). Drug-related grade 3/4 adverse events (AEs) were encountered in 31/87 (36%) of the Phase I/II patients and there was one grade 5 drug-related AE,cerebrovascular accident. Hepatic toxicities (9%), gastrointestinal disorders (7%) and rash (5%) were the most frequent grade 3/4 AEs. AEs possibly related to inhibition of MEK signaling were blurred vision (total,13%; grade 3, 1%) and decreased cardiac ejection fraction (total, 9%; grade 3, 6%); events were generally reversible. Conclusion: At the RP2D of trametinib (2 mg orally daily), trametinib has shown promising clinical activity and responses (CR/CRp/Marrow CR/MLFS/PR) were almost exclusively seen in patients with refractory myeloid malignancies characterized by somatic RAS mutations. Expansion of the CMML cohort for RAS positive subjects is ongoing. Disclosures: Borthakur: GlaxoSmithKline, Sigma-Tau, Eisai, XBiotech: Research Funding. Off Label Use: Trametinib, to report outcome of clinicla trial to audience at ASH meeting. Foran:GlaxoSmithKline: Research Funding. Platzbecker:GlaxoSmithKline: Honoraria, Research Funding. Giagounidis:GlaxoSmithKline: Honoraria. Ottmann:GlaxoSmithKline: Clinical trial participation Other. Kadia:GlaxoSmithKline: Research Funding. Bauman:GlaxoSmithKline: Employment, Equity Ownership. Wu:GlaxoSmithKline: Employment. Liu:GlaxoSmithKline: Employment. Schramek:GlaxoSmithKline: Employment. Zhu:GlaxoSmithKline: Employment. Wissel:GlaxoSmithKline: Employment, Equity Ownership.

Objective To compare the outcomes of Aquablation in 30–80 mL prostates with those in 80–150 mL prostates. Surgical options, especially with short learning curves, are limited when treating large prostates for lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Aquablation (AquaBeam System, PROCEPT BioRobotics Inc., Redwood City, CA, USA) could solve this issue with global reproducibility, independent of prostate volume. Patients and Methods Waterjet Ablation Therapy for Endoscopic Resection of prostate tissue (WATER [W‐I]; NCT02505919) is a prospective, double‐blind, multicentre, international clinical trial comparing Aquablation and transurethral resection of the prostate (TURP) for the treatment of LUTS/BPH in prostates between 30 and 80 mL. WATER II (W‐II; NCT03123250) is a prospective, multicentre, single‐arm international clinical trial of Aquablation in prostates between 80 and 150 mL. We compare baseline parameters and 12‐month outcomes in 116 W‐I and 101 W‐II study patients. Students’ t ‐test or Wilcoxon tests were used for continuous variables and Fisher’s test for binary variables. Results The mean (SD) operative time was 33 (17) and 37 (13) min in W‐I and W‐II, respectively. Actual treatment time was 4 and 8 min in W‐I and W‐II, respectively. The mean change in the International Prostate Symptom Score was substantial averaging (at 12 months) 15.1 in W‐I and 17.1 in W‐II ( P = 0.605). By 3 months, Clavien–Dindo grade ≥II events occurred in 19.8% of W‐I patients and 34.7% of W‐II patients ( P = 0.468). Conclusion Aquablation clinically normalises outcomes between patients with 30–80 mL prostates and patients with 80–150 mL prostates treated for LUTS/BPH, with an expected increase in the risk of complications in larger prostates. Long‐term outcomes of procedure durability are needed.

Abstract Abstract 4029 Introduction: Chromosomal translocation of the FGFR3 oncogene in t(4;14)-positive multiple myeloma (MM) causes FGFR3 overexpression in plasma cells, chemoresistance, and poor prognosis leading to shorter overall survival in MM patients (pts). MFGR1877S is a human monoclonal antibody that targets FGFR3 to prevent ligand binding, receptor-receptor association, and FGFR3 signaling. In preclinical studies, anti-FGFR3 antibody suppresses FGFR3-mediated cell proliferation, and exerts strong anti-tumor activity in mouse xenograft models of both t(4;14)-positive MM and bladder carcinoma. Methods: This Phase I study assessed the safety, tolerability, and biologic activity of MFGR1877S given intravenously, weekly for 3 weeks, followed by every 28-day dosing, to eligible patients with t(4;14)-positive MM. Dose escalation started with single-pt cohorts at 1 and 2 mg/kg, followed by a standard 3+3 dose-escalation scheme at doses ranging from 4–15 mg/kg. Dose escalation decisions were made based on monitoring pts for dose-limiting toxicities (DLT) during the first 22 days on study. FGFR3 expression, safety, pharmacokinetics (PK), and response (EBMT/IMWG criteria) were assessed. Main efficacy outcome measures include serum/urine M protein and free light chain (FLC) quantities. Results: A total of 14 pts (median age 66, range 45–78; 43% female) with a baseline ECOG status of 0–2, and a median number of 5 prior therapies (range 1–10), received a median of 3.5 doses (range 1–7) of MFGR1877S. Adverse events (AEs) deemed related to MFGR1877S were diarrhea, fatigue, and nausea (14% each), and anemia, increased creatinine, bone pain, confusion, decreased appetite, myalgia, and fever (7% each). The only Grade ≥ 3 related AE was fatigue (7%). Six pts experienced 9 serious AEs (SAE), one of which was Grade 2 pyrexia attributed to MFGR1877S that occurred within 24 hours of infusion and required hospitalization. This pt later discontinued due to a second SAE of Grade 2 pyrexia requiring hospitalization not attributed to MFGR1877S. One pt died of intracranial hemorrhage not attributed to MFGR1877S. No Grade 4 SAEs were reported. Other reported SAEs included Grade 3 hypercalcemia, neutropenia, pain in extremity, and musculoskeletal chest pain (1 pt each), Grade 2 ankle fracture, pneumonia, and pyrexia × 2 (1 pt each). No maximum tolerated dose was identified, as no DLTs were observed through the highest dose tested (15 mg/kg). Preliminary PK analysis for limited number of multiple myeloma patients (n=14) by non-linear mixed effect modeling demonstrated a trend of dose proportional increase of exposure (area under the concentration-time curve and maximal concentration) from 2 to 15 mg/kg. Population clearance of MFGR1877S was estimated to be ∼0.62 L/day, suggesting that MFGR1877S appeared to have a slightly faster clearance in MM patients, compared to the typical IgG1 monoclonal antibody clearance in human. The central volume of distribution of MFGR1877S was ∼3.4 L, which approximated human serum volume and appeared similar to the central volume of distribution of other typical IgG1 monoclonal antibodies. While some degree of FGFR3 expression was detected by immunohistochemistry in 10/14 patient bone marrow samples taken at screening, FACS analysis of FGFR3 surface expression on myeloma cells, although largely consistent with IHC measurements, also revealed heterogeneity in the levels of detectable surface FGFR3 expression. Six pts had stable disease as their best response: 2 pts up to 4 cycles, 1 pt up to 3 cycles, and 3 pts up to 1 cycle. Conclusions: MFGR1877S was well-tolerated overall in these patients with multiple relapsed or refractory MM. Although no objective responses were observed, stable disease was observed in 3 pts for 3–4 cycles. Disclosures: Off Label Use: MFGR1877S is a human monoclonal antibody that targets FGFR3 to prevent ligand binding, receptor-receptor association, and FGFR3 signaling. Singhal:Millennium and Celgene: Speakers Bureau. Niesvizky:Onyx, Millemium, Celgene. Speakers bureau: Millenium and Celgene: Consultancy, Research Funding. Comenzo:Millenium, Neotope; Onyx, Osiris, Millenium: Consultancy, Research Funding. Lebovic:Genentech: Speakers Bureau. Choi:Genentech: Employment. Lu:Genentech: Employment. French:Genentech: Employment. Penuel:Genentech: Employment. Ho:Genentech: Employment.

Abstract Abstract 788 FLT3 mutations are common in AML and are associated with poor prognosis. Lestaurtinib is a multi-targeted kinase inhibitor with potent activity against FLT3. In an attempt to definitively establish whether or not there is clinical benefit for FLT3 inhibition in the relapse setting, we conducted a randomized trial of chemotherapy followed by lestaurtinib for patients with FLT3 mutant AML in first relapse. Patients were randomized to receive either chemotherapy alone, consisting of mitoxantrone, etoposide, and cytarabine (MEC) or high-dose cytarabine (HiDAc) depending on the duration of CR1) or chemotherapy followed by 80 mg lestaurtinib orally BID. Patients on the chemotherapy only arm were eligible for crossover if they were refractory to therapy. Patients on the lestaurtinib arm received the drug for up to 112 days on study (they could continue to receive the drug through a separate extension protocol). The primary objective was complete remission (CR/CRp). Secondary objectives included overall survival (OS), safety, and tolerability. From January 2004 through December 2008, 224 patients at 52 different centers were enrolled and randomized, with 220 patients actually receiving therapy. Blood samples from patients on the lestaurtinib arm were obtained at baseline, on Day 15, and on Day 42 for pK studies and for determination of in vivo FLT3 inhibition and measurement of plasma FLT3 ligand (FL) and alpha-1 acid glycoprotein (AGP) levels. The median age for all patients enrolled was 55 years (53.5 in the control arm, 58.5 in the lestaurtinib arm), with 88% having FLT3/ITD mutations, 8% having D835 mutations, and 4% having both. The duration of CR1 was less than 6 months in 47% of patients in each arm. On the lestaurtinib arm, 107 patients received at least 1 week of lestaurtinib (mean 60.1 days, range 8-418), with 17 of these patients receiving drug on the extension protocol. On the chemotherapy only arm, 7 patients crossed over to receive lestaurtinib, and 31 patients went on to receive lestaurtinib on the extension protocol after outcome evaluation. Lestaurtinib was generally well tolerated following chemotherapy, with 104 Grade 3/4 adverse events in the lestaurtinib arm versus 99 in the control arm. There were 61 serious adverse events in the lestaurtinib arm versus 49 in the control arm. Early death (by Day 42) occurred in 22 lestaurtinib patients (2 progressive leukemia, 14 infectious, 6 organ failure) and16 control patients (6 progressive leukemia, 5 infectious, 5 organ failure). By intention to treat analysis, there were 29 CR/CRp in the lestaurtinib arm and 23 in the control arm (26% versus 21%; p = 0.35), with no difference in OS (4.73 months versus 4.57 months) between the two arms. Blood samples from 79 of the 107 lestaurtinib-treated patients obtained on Day 15 were analyzed for FLT3 inhibitory activity (plasma inhibitory activity [PIA] assay), as well as FLT3 ligand (FL), lestaurtinib, and AGP concentrations. Mean lestaurtinib plasma concentration was 12 uM at Day 15 and fell to 7.5 uM on Day 42. Mean lestaurtinib concentration at Day 15 was 13.3 uM in patients achieving CR/CRp and 11.5uM in non-responders. A target of >85% inhibition of FLT3 maintained at trough (pre-dose) was defined from previous studies. Of the 79 patients tested, 46 (58%) achieved this degree of FLT3 inhibition on Day 15. FL concentrations rose from baseline (15.6 pg/mL) to Day 15 (1148 pg/mL), and AGP concentrations rose by an average of 52% over the same period, both of which may have reduced the degree of FLT3 inhibition. Of the 46 patients with target FLT3 inhibition on Day 15, 18 (39%) achieved CR/CRp, while only 3 (9%) of the 32 patients with below target FLT3 inhibition achieved CR/CRp. Thus, in patients with FLT3 mutant AML at first relapse, pharmacokinetic factors and possible physiologic factors (FL and AGP) limit lestaurtinib's ability to effectively inhibit FLT3. FLT3 inhibition by lestaurtinib, when achieved, correlates with better CR rates, but in this trial that benefit was negated by a poor CR rate in those patients for whom the drug did not reach the target level of FLT3 inhibition. Overall, lestaurtinib treatment following re-induction chemotherapy failed to increase response rates or prolong survival of patients with FLT3 mutant AML in first relapse. Disclosures: Levis: Cephalon: Clinical Advisory Board member. Ravandi:Cephalon: Honoraria, Member, clinical advisory board, Research Funding. Erba:Cephalon: Research Funding, Speakers Bureau. Baccarani:Novartis Pharma, Bristol Myers Squibb, Merck Sharp & Dome, Pfizer: Consultancy, Speakers Bureau. Stone:Cephalon: ad hoc consultancy; Novartis: Research Funding, ad hoc consultancy. Advani:Cephalon: Research Funding. Douer:Cephalon: Honoraria, Research Funding, Speakers Bureau. Litzow:Cephalon: Research Funding. Tremmel:Cephalon: Employment, Equity Ownership. Bensen-Kennedy:cephalon: Employment. Smith:Cephalon: Research Funding.

OBJECTIVES: Eosinophilic esophagitis (EoE), a chronic food allergic disease, lacks sensitive and specific peripheral biomarkers. We hypothesized that levels of EoE-related biomarkers captured using a 1-hour minimally invasive Esophageal String Test (EST) would correlate with mucosal eosinophil counts and tissue concentrations of these same biomarkers. We aimed to determine whether a 1-hour EST accurately distinguishes active from inactive EoE or a normal esophagus. METHODS: In a prospective, multisite study, children and adults (ages 7–55 years) undergoing a clinically indicated esophagogastroduodenoscopy performed an EST with an esophageal dwell time of 1 hour. Subjects were divided into 3 groups: active EoE, inactive EoE, and normal esophageal mucosa. Eosinophil-associated protein levels were compared between EST effluents and esophageal biopsy extracts. Statistical modeling was performed to select biomarkers that best correlated with and predicted eosinophilic inflammation. RESULTS: One hundred thirty-four subjects (74 children, 60 adults) with active EoE (n = 62), inactive EoE (n = 37), and patient controls with a normal esophagus (n = 35) completed the study. EST-captured eosinophil-associated biomarkers correlated significantly with peak eosinophils/high-power field, endoscopic visual scoring, and the same proteins extracted from mucosal biopsies. Statistical modeling, using combined eotaxin-3 and major basic protein-1 concentrations, led to the development of EoE scores that distinguished subjects with active EoE from inactive EoE or normal esophagi. Eighty-seven percent of children, 95% of parents, and 92% of adults preferred the EST over endoscopy if it provided similar information. DISCUSSION: The 1-hour EST accurately distinguishes active from inactive EoE in children and adults and may facilitate monitoring of disease activity in a safe and minimally invasive fashion.

Background: The CACNA1C -encoded cardiac L-type calcium channel (Cav1.2) is essential for cardiocyte action potential duration (APD). We previously reported the CACNA1C-p.R518C variant associated with prolonged QT intervals, cardiomyopathy, and sudden cardiac death in several pedigrees. Methods: To characterize a patient-derived human induced pluripotent stem cell–derived cardiomyocyte (hiPSC-CM) CACNA1C-p.R518C model, CACNA1C-p.R518C hiPSC-CMs were generated from a 13-year-old man (QTc, >480 ms) with a family history of sudden cardiac death. An isogenic hiPSC-CM gene-corrected control was created using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat–associated 9). APD and calcium handling were assessed by live cell imaging with Arclight voltage and Fluo-4 calcium indicators, respectively. The APD and L-type calcium channel biophysical properties were further assessed by whole-cell patch clamp technique. Results: The Bazett formula-corrected, Arclight-measured APD 90 of CACNA1C-p.R518C hiPSC-CMs was significantly longer (622±11 ms; n=92) than the isogenic control hiPSC-CMs (453±5 ms; n=62; P <0.0001). Patch clamp assessment of CACNA1C-p.R518C hiPSC-CMs paced at 1 Hz confirmed a prolonged APD 90 (689±29 ms; n=10) compared with the patient’s isogenic control hiPSC-CMs (434±30 ms; n=8; P <0.05). Fluo-4–measured calcium transient decay time suggested calcium mishandling in CACNA1C-p.R518C. Patch clamp analysis revealed increased L-type calcium channel window current, slow decay time at various voltages, and increased late calcium current for CACNA1C-p.R518C hiPSC-CMs when compared with isogenic control hiPSC-CMs. Conclusions: Using patient-specific hiPSC-CM mutant and isogenic control lines, we demonstrate that the CACNA1C-p.R518C variant is the self-sufficient, monogenetic substrate for the patient’s long-QT syndrome phenotype. These data further bolster the conclusion that CACNA1C is a bona fide, definite evidence long-QT syndrome susceptibility gene.

Background: The sex- and gender-specific health (SGSH) multimedia case-based learning modules (MCBLMs) were developed to address the absence of validated or peer-reviewed material that incorporates topics of sex and gender differences into medical curricula. This article provides the methodology for development of the modules and reports the results of a field test of the modules in different medical educational settings. Methods: MCBLMs were created by a multidisciplinary committee of scientists, health profession educators, and students. Two modules, osteoporosis and diabetes, were tested in various settings based on the curricular needs at each of the five accredited institutions. Each module consisted of a pretest and three interactive, multimedia stand-alone sections with post-tests. Scores on the tests were compared using a paired-samples t -test. A postmodule survey was used to evaluate the format. Results: Four hundred eighteen students participated in the field testing. For the 194 who completed the osteoporosis module, the post-test scores (M = 13.71, standard deviation [SD] = 2.09) were significantly higher than the pretest scores (M = 10.54, SD = 2.41), p < 0.001. Post-test scores for the 285 who completed the diabetes module (M = 16.55, SD = 2.46) were also significantly higher than the pretest scores (M = 13.71, SD = 2.09), p < 0.001. The postmodule survey showed positive acceptance of the format with an average score of 3.54/4 for osteoporosis and 3.45/4 for diabetes. Conclusion: The SGSH MCBLM field testing results show that the modules have a positive effect on content knowledge in multiple settings and are well accepted by learners.

AbstractThere are currently no effective treatments for advanced‐stage papillary renal cell carcinoma (PRCC). The goal of this study is to define potential DNA methylation‐based markers and treatment targets for advanced‐stage type 2 PRCC. Progressive DNA methylation changes and copy number variation (CNV) from localized to advanced‐stage type 2 PRCC are analyzed by using methylation data generated by TCGA's kidney renal papillary cell carcinoma (TCGA‐KIRP, 450k array) project. Survival analyses are performed for the identified biomarkers and genes with CNV. In addition, expression of the corresponding genes is investigated by RNA‐seq analysis. Progressive methylation changes in several CpGs from localized to advanced‐stage type 2 PRCC are observed. Four CpGs (cg00489401, cg27649239, cg20555674, and cg07196505) in particular are identified as markers for differentiating between localized and advanced‐stage type 2 PRCC. Copy number analysis reveals that copy gain of PTK7 mostly occurs in advanced‐stage type 2 PRCC. Both the four CpG methylation changes and PTK7 copy number gain are associated with patient survival. RNA‐seq analysis demonstrates that PTK7 copy gain leads to higher PTK7 expression relative to tumors without copy number gain. Moreover, PTK7 is significantly upregulated from localized to advanced‐stage type 2 PRCC and is linked to cancer cell invasion. In conclusion, DNA methylation markers that differentiate between localized and advanced‐stage type 2 PRCC may serve as useful markers for disease staging or outcome, while PTK7 copy gain represents a potential treatment target for advanced‐stage type 2 PRCC. Stepwise methylation changes and copy number gain also associate with disease stage in PRCC patients.

Abstract HLA-haploidentical hematopoietic cell transplantation (Haplo-HCT) using posttransplantation cyclophosphamide (PT-Cy) has improved donor availability. However, a matched sibling donor (MSD) is still considered the optimal donor. Using the Center for International Blood and Marrow Transplant Research database, we compared outcomes after Haplo-HCT vs MSD in patients with acute myeloid leukemia (AML) in first complete remission (CR1). Data from 1205 adult CR1 AML patients (2008-2015) were analyzed. A total of 336 patients underwent PT-Cy–based Haplo-HCT and 869 underwent MSD using calcineurin inhibitor–based graft-versus-host disease (GVHD) prophylaxis. The Haplo-HCT group included more reduced-intensity conditioning (65% vs 30%) and bone marrow grafts (62% vs 7%), consistent with current practice. In multivariable analysis, Haplo-HCT and MSD groups were not different with regard to overall survival (P = .15), leukemia-free survival (P = .50), nonrelapse mortality (P = .16), relapse (P = .90), or grade II-IV acute GVHD (P = .98). However, the Haplo-HCT group had a significantly lower rate of chronic GVHD (hazard ratio, 0.38; 95% confidence interval, 0.30-0.48; P &lt; .001). Results of subgroup analyses by conditioning intensity and graft source suggested that the reduced incidence of chronic GVHD in Haplo-HCT is not limited to a specific graft source or conditioning intensity. Center effect and minimal residual disease–donor type interaction were not predictors of outcome. Our results indicate a lower rate of chronic GVHD after PT-Cy–based Haplo-HCT vs MSD using calcineurin inhibitor–based GVHD prophylaxis, but similar other outcomes, in patients with AML in CR1. Haplo-HCT is a viable alternative to MSD in these patients.