Woolfson, Adrian

Abstract Background BMS-911543 is an oral, selective small-molecule inhibitor of JAK2 (IC50=1.1nM) with potent anti-proliferative and pharmacodynamic effects in cell lines and in vivo models dependent upon JAK2 signaling. In vitro, BMS-911543 demonstrates high selectivity within the JAK family (JAK1 [IC50=356nM], JAK3 [IC50=73nM] or TYK2 [IC50=66nM]) and across a large kinase panel (at 1 µM concentration of BMS-911543, only 8 of 451 kinases were markedly inhibited [≥67%]) It also has little activity in cells dependent on other JAK family pathways. Anti-proliferative responses were observed with BMS-911543 in colony growth assays using primary progenitor cells isolated from patients with JAK2V617F-positive polycythemia vera (PV) (Leukemia 2012;26:280). Methods In a multicenter phase 1/2a study, BMS-911543 was administered orally using a BID dosing schedule, in patients with high-, intermediate-2 or intermediate-1 risk symptomatic primary or secondary MF (JAK2 WT or mutant) with platelet counts ≥50,000/mm3. Patients were not required to have palpable splenomegaly. The aim of the study is to determine safety, maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, and preliminary efficacy of BMS-911543. Safety was assessed using NCI-CTCAE version 4.0. Treatment effect was assessed using the International Working Group (IWG) response criteria, MF-SAF, BFI, physical examination, spleen and liver volume assessment by MRI, bone marrow morphology, karyotype, V617F mutant allele burden, plasma cytokine analysis, circulating CD34+ cells and other molecular parameters. Current status To date, 84 patients have been treated (dose escalation [n=42]; dose expansion [n=42]) and the maximum tolerated dose (MTD) was defined as 200mg BID. The summary below represents an interim data analysis of 36 patients from the dose escalation phase dosed at 5, 10, 20, 40, 80, 120, 160, and 200mg BID. Fifteen of 36 (42%) patients had received prior Jak inhibitors (Jaki) including 3 who had received ≥2 Jak inhibitors. PK, PD, Safety, Tolerability and Efficacy After repeat dosing, greater than dose-proportional increase in the Cmax and AUC, and drug accumulation was observed at doses ≥40mg BID. PD analysis indicated inhibition of JAK/STAT pathway signaling activity in peripheral blood mononuclear cells, and modulation of several soluble peripheral blood proteins including IL-6, EPO and Leptin. Eleven patients (31%) had drug-related AEs. The nine hematological AEs included 3 anemia (1 grade 3 and 2 grade 2); 3 neutropenia (grade 4); and single leukopenia (grade 4), thrombocytopenia (grade 4), and reduction in platelet count (grade 2). Nine non-hematological AEs included 3 nausea (grade1/2); amylase increased (grade 3) and lipase increased (grade 3) one each; and grade 1 fatigue, muscle spasms, insomnia, erectile dysfunction one each. Ten patients (28%) discontinued treatment: 4 were attributed to disease progression, 2 to lack of efficacy, 2 at patient’s request, 1 to poor compliance, and 1 to unrelated AE. Spleen volume reductions (SVR) by MRI were observed in Jaki failure and in Jaki naive patients. Of 11 patients treated at 160 and 200mg, 8 patients (73%) had SVR greater than 35% at 3 months. In contrast, 1 of 4 patients treated at 120mg and none treated below 120mg had SVR greater than 35%. Of the patients treated at 160mg and 200mg, more than 50% had MF-SAF reductions > 50%. Overall, 3 patients (8.3%; 2 treated at 10mg BID and 1 at 200mg BID) had an increase in hemoglobin of ≥2g/dL;. Other signs of clinical activity included reductions in V617F mutant allele burden, leukocytosis, leukoerythroblastosis, circulating CD34+ cells, and LDH. Conclusion BMS-911543 was generally well tolerated and has an acceptable safety and efficacy profile. BMS-911543 induced rapid control of constitutional symptoms, and splenomegaly in patients with symptomatic MF, including those previously treated with one or more Jak inhibitors. Updated data from all 84 patients who have been treated in the dose escalation and ongoing expansion phases, including MRI assessments of spleen and liver volume, V617F mutant allele burden and levels of select plasma cytokines, will be presented.</abstract> Disclosures: Pardanani: JW Pharmaceutical Corp.: Clinical trial support, Clinical trial support Other; PharmaMar: Clinical trial support, Clinical trial support Other; Sanofi: Clinical trial support, Publication support services, Clinical trial support, Publication support services Other; Bristol Myers Squibb: Clinical trial support Other. Off Label Use: Use of BMS-911543, Ruxolitinib, Momelotinib, Fedratinib and Pomalidomide for treatment of Myelofibrosis in Clinical Trial setting. Roberts:AbbVie, Inc.: Research Funding; Genentech: Research Funding; Walter and Eliza Hall Institute of Medical Research: Employee, recieves commercial income related to ABT-199, Employee, recieves commercial income related to ABT-199 Other, Employment. Seymour:Genentech: Consultancy, Membership on an entity’s Board of Directors or advisory committees. Verstovsek:Incyte Corporation: Research Funding. Yoshitsugu:Bristol-Myers Squibb: Employment, Equity Ownership. Gestone:Bristol-Myers Squibb: Employment, Equity Ownership. Phillips:Bristol-Myers Squibb: Employment, Equity Ownership. Xing:Bristol-Myers Squibb: Employment, Equity Ownership. Peltz:Bristol-Myers Squibb: Employment, Equity Ownership. Lorenzi:Bristol-Myers Squibb: Equity Ownership, Former employment Other. Alland:Bristol-Myers Squibb: Employment, Equity Ownership. Woolfson:Bristol-Myers Squibb: Equity Ownership, Former employment Other.

TPS7575 Background: Approximately 50% of patients (pts) with advanced DLBCL are refractory to or relapse following first line R-CHOP therapy. Pts with R/R DLBCL have limited treatment options and a poor prognosis. This study assesses immunotherapy-based regimens containing avelumab (a fully human IgG1 anti–PD-L1 antibody) in combination with utomilumab (a novel 4-1BB agonist), azacitidine, rituximab, and/or conventional chemotherapy (CT; bendamustine) in pts with R/R DLBCL. Methods: JAVELIN DLBCL (NCT02951156) is a global, multicenter, randomized, open-label, 2-component(phase 1b followed by phase 3) study of avelumab-based combination regimens in R/R DLBCL. In phase 1b, up to 84 pts will be randomized 1:1:1 to receive avelumab/rituximab/utomilumab, or avelumab/azacitidine/utomilumab, or avelumab/rituximab/bendamustine. The primary phase 1b objectives are preliminary assessments of dose-limiting toxicities (n = 6 per arm) and efficacy (objective response [OR]; n = 28 per arm). One regimen from phase 1b will be selected for phase 3 evaluation in 220 additional pts randomized 1:1 to the chosen regimen or investigator’s choice CT (rituximab/bendamustine or rituximab/gemcitabine/oxaliplatin). The primary phase 3 objective is to demonstrate progression-free survival (PFS) superiority of the avelumab-based regimen over CT. Overall survival is a key secondary endpoint. Eligible pts have completed up to 4 lines of prior rituximab/multiagent CT, and/or have failed autologous stem cell transplantation (ASCT), or are not eligible for intensive CT or ASCT. Other eligibility criteria include ECOG PS ≤1 and no prior therapy with a checkpoint inhibitor. Treatment with avelumab, utomilumab, and azacitidine will be continued until the pt no longer receives clinical benefit; rituximab and bendamustine are limited to 8 and 6 cycles, respectively. OR and PFS will be assessed per Lugano disease classification criteria. Other secondary efficacy endpoints include disease control, duration of response, time to response, and minimal residual disease burden. Safety, PK, immunogenicity, pt-reported outcomes, and biomarkers will also be evaluated. Clinical trial information: NCT02951156.

7061 Background: Glasdegib is a small molecule inhibitor of the Sonic Hedgehog pathway, and data from the single arm, lead-in cohort of a phase 1b/2 trial in myelofibrosis (MF) are shown. Methods: Patients (age ≥18 yrs) with primary/secondary MF previously-treated with ≥1 Janus Kinase inhibitor (JAKi) were enrolled and received glasdegib 100 mg QD orally in 28 day cycles. AEs and laboratory abnormalities were assessed. Key efficacy endpoints were proportion of patients with spleen volume reduction (SVR) ≥35% and ≥50% reduction in total symptom score (TSS) measured by the MPN Symptom Assessment Diary (MPN-SAD) at Week 24. Results: 21 patients were enrolled between Oct '14-Oct '15 in this ongoing study. Mean age was 69.3 yrs (range 58-83). Median duration of treatment was 85 days (22-343). 52% were refractory patients with inadequate response to prior JAKi. Baseline symptoms were mostly mild (1-4), except fatigue (>4). No patients achieved SVR ≥35%, 5 patients had some SVR (maximum 2.3-21.4% reduction from baseline), and no progressive disease prior to Day 71. At week 24, 1 patient had ≥50% reduction in TSS, but 3/21 and 4/21, respectively showed 30% and 20% TSS reduction. Of 14 patients with severe baseline symptoms (1 with ≥5, or ≥2 with ≥3), 1, 1, and 2 achieved 50%, 30%, and 20% TSS reduction, respectively at week 24. TSS, spleen-related, and constitutional symptom scores showed a trend of reduction over 24 weeks with spleen-related symptoms, inactivity, and fatigue showing greatest improvement (52%, 58%, and 36%, respectively). Dysgeusia (N=13), muscle spasms (N=12), alopecia (N=8), decreased appetite (N=7), fatigue (N=7), lipase increase (N=5), and weight decrease (N=5) occurred in ≥20% patients. None, except 1 episode of fatigue, were considered serious AEs. Glasdegib steady state PK was consistent with previous single agent data. Conclusions: Glasdegib has an acceptable toxicity profile in patients with primary/secondary MF previously treated with JAKi. Symptom responder definition for refractory patients may not be the same as for JAKi naïve patients. Patient reported symptom improvement may be a more sensitive indicator of treatment benefit vs SVR. Further study of glasdegib may be warranted. Clinical Trial Information: NCT02226172.