ALBERT

Description: Abstract 4082 Background: ARRY-520, a novel kinesin spindle protein (KSP) inhibitor, has been studied as a single agent and in combination with dexamethasone, and demonstrated promising clinical activity in patients with bortezomib- and lenalidomide-refractory multiple myeloma (MM). Carfilzomib, a novel irreversible proteasome inhibitor (PI), has also demonstrated single agent activity in relapsed and refractory MM, and recently received regulatory approval for this indication. Preclinical data support the presence of synergy with the combination of a PI and a KSP inhibitor via the latter's ability to down-regulate Mcl-1, supporting our hypothesis that the combination of carfilzomib and ARRY-520 (Car-ARRY) would be highly active in relapsed and/or refractory myeloma. We therefore aimed to combine these two agents for the first time, and here report the initial findings from the phase I dose-escalation in patients with relapsed and/or refractory MM. Methods: The primary objective was to determine the maximum tolerated dose (MTD) and the safety/tolerability of the Car-ARRY combination. Secondary objectives were to determine efficacy as measured by the overall response rate, time to progression, progression free survival and time to next therapy. Patients had to have myeloma that was relapsed and/or refractory, be ineligible for autologous stem cell transplant, bortezomib refractory/intolerant, and prior lenalidomide exposure. ARRY-520 was administered intravenously over 1 hour on days 1, 2, 15 and 16, while carfilzomib was administered intravenously over 30 minutes on days 1, 2, 8, 9, 15 and 16 on a 28 day cycle. All patients received growth factor support with filgrastim. Dose-escalation used a standard 3+3 schema proceeded based on dose-limiting toxicities (DLTs) during cycle 1, with planned escalation of the dose of ARRY-520. Dose level 1 was ARRY-520 0.75 mg/m2, and carfilzomib was dosed at 20 mg/m2 for cycle 1 on days 1 and 2 and all subsequent dose were at 27 mg/m2. Adverse events (AEs) were graded by NCI-CTCAE v4, while responses were assessed by the modified International Uniform Response Criteria. Results: To date, 8 patients have been enrolled in the ongoing dose escalation phase. The median age was 66 (range 47–80), 6/8 were males, and the median number of prior therapies was 4 (range 2–10). 7/8 patients had undergone prior autologous stem cell transplant, and all patients were bortezomib refractory or intolerant. In the first cohort, 3 patients were enrolled and no dole limiting toxicity (DLT) was observed. During the second cohort, ARRY-520 was escalated to 1 mg/m2 with carfilzomib at 20/27 mg/m2, and among the first 3 patients, one patient suffered a DLT in the form of an admission for influenza pneumonia with non-neutropenic fever. Expansion of cohort 2 is currently underway. Among the 6 patients who completed the first cycle of therapy, 5 remain on study. In the first cohort, one patient remains on study with 6 cycles and achieved a near complete remission, 1 patient achieved stable disease, and 1 patient suffered disease progression after first cycle. In the second cohort, all three patients who completed the first cycle have stable disease and remain on trial. In the first 6 toxicity-evaluable patients who have completed one cycle, grade (G) 3 events included one each of pneumonia, diarrhea, and hyperglycemia. There was limited hematologic toxicity with 4/6 patients with G1/2 thrombocytopenia, 3/6 patients with G1/2 anemia, and 1/6 patient with G1/2 neutropenia. Additional G1/2 non-hematologic toxicity included 3/6 patients with diarrhea, 3/6 patients with dyspnea, 3/6 patients with transient elevations in creatinine and 3/6 patients with aspartate aminotransferase elevations. An MTD has not been established and enrollment is ongoing in cohort 2 with carfilzomib at 20/27mg/m2 and ARRY-520 at 1.0 mg/m2. Conclusions: The combination of ARRY-520 and carfilzomib is well tolerated with limited hematologic toxicity and a manageable side effect profile. Notably, in this patient population, with patients who have bortezomib refractory/intolerant myeloma, the combination has demonstrated early signals of activity. Updated safety and efficacy data for all patients will be presented at the meeting. Disclosures: Shah: Onyx: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Array BioPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau. Off Label Use: This presentation will include information about Arry-520 which is not yet approved for use in patients with multiple myeloma. Wang:Pharmacyclic: Research Funding; onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hilder:Array BioPharma: Employment. Orlowski:onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; array biopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Description: Abstract 449 Background ARRY-520 is a kinesin spindle protein (KSP) inhibitor that arrests cells in mitosis and induces apoptosis due to degradation of the BCL2 family survival protein MCL-1. As previously reported, ARRY-520 has demonstrated single-agent activity in relapsed and refractory multiple myeloma (RRMM). In preclinical myeloma models, the addition of dexamethasone (Dex) increases the activity of ARRY-520, supporting clinical investigation of ARRY-520 combined with low-dose Dex (LoDex). Here, the efficacy and safety of ARRY-520 is compared in 2 Phase 2 cohorts in RRMM: as a single agent (Cohort 1) and in combination with LoDex (Cohort 2). Methods Both cohorts were designed as 2-stage single-arm Phase 2 studies. Cohort 1 evaluated the efficacy and safety of 1.5 mg/m2/d ARRY-520 administered intravenously on Days 1 and 2 every 2 weeks with prophylactic granulocyte colony-stimulating factor (G-CSF) support. Eligible patients had RRMM with 2 prior lines of therapy that included both bortezomib (BTZ) and an immunomodulatory agent (IMiD), unless refusing or ineligible for this therapy. Cohort 2 is evaluating the efficacy and safety of the same dose and schedule of ARRY-520 and G-CSF with LoDex (40 mg PO weekly). Eligible patients had RRMM with 2 prior lines of therapy, and had disease refractory to (progressed on or ≤ 60 days of treatment) their last line of therapy and that was refractory to BTZ, lenalidomide (Len) and dexamethasone. Data from Cohort 1 and the first stage of Cohort 2 are reported. Results At the time of data cutoff, a total of 32 patients were enrolled into Cohort 1 with a median age of 65 years (range 51–82) and a median of 6 prior regimens (range 2–19). All patients received prior IMiD, 90% received prior BTZ and 78% had prior autologous stem cell transplant (ASCT). The defined first stage of Cohort 2 has been enrolled with 18 evaluable patients. These patients had a median age of 67 years (range 53–78) and were more heavily pretreated, with a median of 10 prior therapies (range 5–13). Safety was similar for both cohorts. A possible trend for more infections in Cohort 2 was noted. The most commonly reported (20% of patients) treatment-related adverse events (AEs) in both cohorts included thrombocytopenia, anemia, neutropenia and fatigue. No treatment-related events of neuropathy were observed in either cohort. The most common Gr 3/4 AEs (in Cohort 1, Cohort 2) included neutropenia (38%, 33%), thrombocytopenia (44%, 44%) anemia (28%, 50%), pneumonia (3%, 17%) and fatigue (16%, 11%). Treatment discontinuations due to AEs were infrequent (9%, 11%). Of 32 patients in Cohort 1, confirmed responses (≥ Minor Response (MR)) were observed in 6 patients (19%) with 5 Partial responses (PR) (16%) per International Melanoma Working Group (IMWG) and European Group for Blood and Marrow Transplantation (EBMT) criteria. The median treatment time was 2.1 months. In the subset of patients with disease refractory to both BTZ and Len, a 15% overall response rate (ORR ≥ MR) was observed. Among the 18 evaluable patients in Cohort 2, the ORR (≥ MR) was 28% (5/18), with 4 patients ≥ PR (22%). At the time of data cutoff, the median treatment time was 3.9 months. Summary Patients with RRMM refractory to both IMiD and proteasome inhibitor therapy have a poor prognosis with median survival of as little as 6 months1. New drugs with clinically meaningful activity in this population are needed. ARRY-520 is a novel agent with a distinct mechanism of action relative to other myeloma drugs and shows promising clinical activity both alone and combined with Dex in RRMM. Notably, in patients with triple-refractory MM, ARRY-520 + LoDex has shown a preliminary 28% ORR (≥ MR), with a manageable safety profile. These data are comparable to those reported for pomalidomide or carfilzomib in less heavily pretreated patients. Both the median time on study and ORR in Cohort 2 were greater than the activity seen for Cohort 1, despite the more advanced stage of these patients and the fact that they were heavily pretreated with Dex, suggesting that LoDex may enhance ARRY-520 activity. Based on this evidence of activity, further development of ARRY-520 + LoDex is warranted in patients who have exhausted other therapeutic options. Disclosures: Shah: Array BioPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau. Off Label Use: ARRY-520. Zonder:Millenium: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Kaufman:Onyx: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Millenium: Consultancy. Orlowski:Array BioPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees. Walker:Array BioPharma: Employment. Hilder:Array BioPharma: Employment. Ptaszynski:Array BioPharma: Consultancy. Lonial:Onyx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Meyers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Description: Abstract 1868 Background ARRY-520 is a kinesin spindle protein (KSP) inhibitor that has demonstrated clinical activity in patients with relapsed and refractory multiple myeloma (MM). Although ARRY-520 is administered IV, it displays variable pharmacokinetics (PK) among patients. The degree of binding of certain drugs to serum proteins can alter their free fraction (fu) and PK, with a possible impact on clinical activity. Alpha 1-acid glycoprotein (AAG) is an acute-phase reactant protein that is often elevated in the blood of patients with cancer, including multiple myeloma. We investigated the significance of the interaction of ARRY-520 with AAG, and other relevant blood proteins, using both in vitro models and clinical data. Methods Compound-protein binding was assessed using several in vitro assays. In addition, the effect of increasing concentrations of AAG on MM cell line viability was measured. Patient data were obtained from 3 clinical studies of ARRY-520: a Phase 1 solid tumor study, a Phase 1/2 AML study, and a Phase 1/2 study in MM. The MM Phase 2 portion consists of 2 separate, 2-stage cohorts. Cohort 1 evaluated ARRY-520 administered as a single agent, and cohort 2 investigated ARRY-520 in combination with low-dose dexamethasone (LoDex). The concentrations of multiple proteins, including AAG, and the degree of ARRY-520 total protein binding, were measured in pre- and post-dose blood samples for patients in the analysis. AAG levels in MM patients were further correlated with time-on-study and clinical response rate. Results ARRY-520 exhibits low micromolar affinity for AAG in in vitro assays, but not for other common serum proteins, such as albumin. To investigate whether AAG binding impacts biological activity, we found that increasing AAG concentrations within a clinically relevant range resulted in increasing IC50 values for ARRY-520 on MM cell line viability. Of other MM agents tested, none exhibited high affinity binding to AAG in vitro, and a range of AAG concentrations did not alter the cellular activity of these compounds. Pre-dose concentrations of AAG were measured using blood samples collected from patients on all 3 ARRY-520 studies (0.4 – 4.1 g/L AAG in solid tumor study; 0.5 – 2.4 g/L in AML study; 0.2 – 2.8 g/L in MM study). Post-dose blood samples from the MM study also indicated that AAG levels do not significantly change with time. The fu of ARRY-520 in blood was meaningfully reduced among patients with the highest AAG concentrations. Furthermore, AAG and fu were correlated with changes in clinical PK: CL and Vd decreased with increasing AAG, trends consistent with a lower fu. Among the MM patients, 72 patients were evaluable for AAG determination (27 from the dose-escalation portion, 27 from Cohort 1, and 18 from Stage 1 of Cohort 2). Across all of these cohorts, the group of patients with AAG above an empirically-determined cutoff of 1.1 g/L showed a decreased median time on study (1.5 months vs 4.7 months) and no clinical responses (0/19 vs 12/53) as compared to patients below this cutoff. For example, as reported separately, ARRY-520 in combination with LoDex showed a promising 22% overall response rate (≥PR) in the 1st-stage of Cohort 2. In this cohort, 6 patients were determined to have AAG concentrations above the empirical cutoff. None of these patients had clinical benefit. Excluding these 6 patients would significantly improve the overall response rate (≥PR) from 22% (4/18) to 33% (4/12). Summary AAG has been proposed as a prognostic marker for MM disease severitya. Our preliminary data suggest that AAG levels can affect the free fraction of ARRY-520 in blood over a clinically relevant range both preclinically and in clinical studies. In retrospective analysis, patients with higher AAG levels show a lower fu and therefore may not achieve sufficient exposure to gain therapeutic benefit from ARRY-520. In preclinical analyses, this effect is specific to ARRY-520, suggesting that AAG levels may be predictive for ARRY-520 activity relative to other MM drugs. We hypothesize that prospective screening for AAG may enable exclusion of patients who may not achieve therapeutic exposure to ARRY-520, increasing the overall activity of ARRY-520 and preventing exposure of non-responders to an ineffective therapeutic dose. Further, experiments are currently underway to investigate the relevance of other acute-phase proteins in blood. Disclosures: Tunquist: Array BioPharma: Employment. Off Label Use: ARRY-520 alone and with dexamethasone for the treatment of relapsed/refractory multiple myeloma. ARRY-520 is not currently approved for any indication. Brown:Array BioPharma: Employment. Hingorani:Array BioPharma: Employment. Lonial:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Meyers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kaufman:Millenium: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Onyx: Consultancy. Zonder:Celgene: Honoraria, Research Funding; Millenium: Honoraria, Research Funding. Orlowski:Array BioPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees. Shah:Array BioPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau. Hilder:Array BioPharma: Employment. Ptaszynski:Array BioPharma: Consultancy. Koch:Array BioPharma: Employment. Litwiler:Array BioPharma: Employment. Walker:Array BioPharma: Employment.

Description: Late-Holocene environmental and climatic conditions were reconstructed from diatom assemblages in sediment cores from four western Montana lakes: Crevice Lake, Foy Lake, Morrison Lake, and Reservoir Lake. The lakes show synchroneity in timing of shifts in diatom community structure, but the nature of these changes differs among the lakes. Two of the sites provide highly resolved records of hydrologic balance, while the other two stratigraphic sequences primarily record temperature impact on lake thermal structure. All four lakes show significant change in five discrete intervals: 2200–2100, 1700–1600, 1350–1200, 800–600, and 250 cal yr BP. The similarities in the timing of change suggest overlying regional climatic influences on lake dynamics. The 800–600 cal yr BP shift is evident in other paleorecords throughout the Great Plains and western US, associated with the transition from the Medieval Climate Anomaly to the Little Ice Age. Large-scale climatic mechanisms that influence these lake environments may result from atmospheric circulation patterns that are driven by interactions between Pacific and Atlantic sea-surface temperatures, which are then locally modified by topography.