Abstract: 35 Background: Although the impact of patient access to health records and providers has not been well studied in cancer populations, these applications are now widely employed at cancer centers nationwide. Understanding implications of this practice in cancer patients is critical as patient-reported symptoms may be more likely to represent medical emergencies and test results may be more likely to represent major clinical developments. Methods: Retrospective analysis of enrollment in and use of MyChart, an internet-based patient portal for the EPIC electronic medical record, among patients seen at the Harold C. Simmons Cancer Center at UT Southwestern Medical Center. Predictors of MyChart use were analyzed through univariate and multivariate regression models. Results: A total of 6,495 patients enrolled in MyChart (2006-2012). Mean age was 60 ± 13 years, and 67% were female. The number of patients enrolling per year increased more than five-fold - 181 in 2006 to 1,146 in 2012. The total number of MyChart log-ins was 707,746. Per patient, median total log-ins was 57 (range 1-10,347). In a multivariate model, increased MyChart use was associated with male gender (p=0.01) and with cancer type (p 〈 0.001), with highest rates among patients with genitourinary and upper aerodigestive malignancies. The most common MyChart activities were review of laboratory and radiology results (35%), communicating with providers (34%) [including messaging (29%) and medical advice request (5%)], and appointment scheduling/canceling (18%). Eighty-nine percent of log-ins occurred Monday-Friday. Login-times were 8a-5p (72%), 5p-11p (17%), and 11p-8a (11%). Approximately 32% of messaging (40% of medical advice requests) occurred outside clinic hours. Conclusions: Patient use of an internet-based patient health portal at an NCI-designated cancer center increased dramatically in recent years. The most common activities were viewing of test results and messaging with providers. A substantial proportion of messaging, particularly advice requests, occurred outside clinic hours. Further study of this technology is needed to understand its impact on patient safety, patient/provider satisfaction, and quality of care.

Abstract: Abstract 2997 HDAC enzymes, whose activity has been linked to the transcription of DNA in several cancers including multiple myeloma (MM), are being studied as novel therapeutic targets. Four classes of HDAC enzymes have been identified and several non-specific pan-HDAC and class I HDAC inhibitors have been evaluated in clinical studies. HDAC6, a class II HDAC, has recently been linked to the activity of aggresomes that degrade unfolded and misfolded ubiquitinated proteins. Importantly, targeting both proteasomal and aggresomal protein degradation systems with proteasome inhibitors and HDAC inhibitors respectively, induces accumulation of polyubiquitinated proteins, followed by activation of apoptotic cascades and synergistic cytotoxocity. Here we investigated the preclinical activity of an HDAC6 selective inhibitor ACY-1215 in MM, either alone or in combination with bortezomib. In vitro enzyme assays showed that ACY-1215 has potent inhibitory activity against HDAC6 (IC50 0.0054 μ M) compared to the other HDACs, including Class I HDACs. Maximal cytotoxicity of ACY-1215 against MM cell lines was observed at 48h, with IC50 values ranging from 2–8 μ M. ACY-1215 was also effective against patient MM cells, including bortezomib resistant MM cells, without significant cytotoxicity in normal peripheral blood mononuclear cells (PBMCs). Moreover, ACY-1215 in a dose-dependent manner inhibited DNA synthesis of MM cells at 48h triggered either by binding to bone marrow stromal cells (BMSCs) or by exogenous IL6 and IGF-1, confirming its ability to overcome the proliferative advantage conferred by BMSCs and cytokines. We next studied whether the highly selective HDAC6 inhibitor ACY-1215 could achieve the same efficacy as a pan-HDAC inhibitor such as SAHA, but with less toxicity. Compared to SAHA, ACY-1215 was not toxic to PHA stimulated PBMCs. Importantly, both ACY-1215 and SAHA induced dose-dependent acetylation of α-tubulin in MM.1S cells, but ACY-1215 induced less potent acetylation of lysine on histone H3 and histone H4 than SAHA, further confirming its specific inhibitory effect on HDAC6 activity. We next combined low doses of ACY-1215 to inhibit aggressomal with bortezomib to inhibit proteasomal protein degradation, and showed synergistic anti MM activity (Combination Index 〈 0.9), resulting in apoptosis via the activation of caspase-8,-9,-3 and poly (ADP) ribosome polymerase. Annexin V+PI+ staining after 24h treatment confirmed increased cells in early and late apoptosis after combined therapy (83.6%) compared to ACY-1215 1μ M (10.2%) or bortezomib 5 nM (36.6%) treatment alone. Since NF-kB pathway plays a crucial role in MM cell survival and bortezomib triggers NF-κB activity in some MM cell lines, we next investigated the effect of combined therapy on NF-κB activity. MM.1S cells were co-cultured with BMSCs and then treated with bortezomib 5nM, ACY-1215 1μ M, or the combination. Interestingly, bortezomib treatment significantly enhanced NF-κB activity in MM.1S cells co-cultured with BMSCs, whereas ACY-1215 treatment resulted in only a modest increase in NF-κB activity. Importantly, combined therapy was associated with partial abrogation of bortezomib-induced NF-κb activity. Ongoing studies are determining whether this effect on NF-κB activity contributes to the cytotoxic effect of ACY-1215/bortezomib combination therapy. Finally, we confirmed the synergistic anti-MM activity of ACY-1215 and bortezomib in vivo using two different xenograft mouse models: human MM injected subcutaneously (plasmacytoma model); and luciferase-expressing human MM injected intravenously (disseminated MM model). In the, plasmacytoma model, daily (5×/week) dosing of ACY-1215 (IP: 50 mg/kg) and bortezomib (IV: 0.5 mg/kg) given twice weekly significantly inhibited tumor growth (p 〈 0.0001) and prolonged survival (34 days in the combined treatment group versus 22 days in the control group, p 〈 0.0011). In the disseminated MM model, daily (5x/week) dosing of ACY-1215 (IP: 75 mg/kg) and bortezomib (IP: 1.5mg/kg) once weekly significantly inhibited tumor growth (p 〈 0.0001) and prolonged survival (40 days in the combined treatment group versus 17 days in the control group, p 〈 0.0001). Importantly, no significant adverse effects were noted in either in vivo model. These results therefore provide the preclinical rationale for clinical trials of ACY-1215 together with bortezomib in the treatment of MM. Disclosures: Jarpe: Acetylon: Employment. Anderson:MILLENNIUM: Consultancy; CELGENE: Consultancy; NOVARTIS: Consultancy; ONYX: Consultancy; MERCK: Consultancy; BMS: Consultancy; Acetylon: Membership on an entity's Board of Directors or advisory committees. Jones:Acetylon: Employment. Raje:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Astra Zeneca: Research Funding; Acetylon: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees.

Abstract: Abstract 2912 HDAC enzymes are being studied as novel therapeutic targets in several cancers including multiple myeloma (MM). In particular, the combination of proteasome inhibitors (e.g. bortezomib (BZ)) with Histone Deacetylase (HDAC) inhibitors have shown very promising results in pre-clinical MM models. HDAC6, a Class II HDAC, has been linked to the activity of aggresomes that degrade unfolded and misfolded ubiquitinated proteins. Targeting both proteasomal and aggresomal protein degradation systems with proteasome inhibitors and HDAC inhibitors, respectively, induces accumulation of polyubiquitinated proteins, followed by activation of apoptotic cascades. Here we investigated the preclinical activity of an HDAC6 selective inhibitor ACY-1215 in MM, either alone or in combination with BZ. In vitro enzyme assays showed that ACY-1215 has potent inhibitory activity against HDAC6 (IC50 0.0054 mM) compared to the other HDACs, including Class I HDACs. Maximal cytotoxicity of ACY-1215 against MM cell lines was observed at 48h, with IC50 values ranging from 2–8 μM. To investigate the specific inhibitory effect of ACY-1215 on HDAC6 activity, we evaluated its effect on acetylation of a-tubulin. ACY-1215 induces potent acetylation of a-tubulin at low doses and triggers acetylation of lysine on histone H3 and histone H4 only at much higher doses, confirming its selective inhibitory effect on HDAC6 activity. Importantly, this selective inhibition was also observed in patient MM cells, where ACY-1215 increased acetylated a-tubulin after 4 h of treatment. We next combined low doses of ACY-1215 with BZ and showed synergistic anti MM activity, resulting in apoptosis via caspase-3, -8, -9 and poly (ADP) ribosome polymerase activation. Moreover, the combination of ACY-1215 plus BZ increased the accumulation of polyubiquitinated proteins compared to either agent alone. To investigate the effect of ACY-1215 on aggresome formation, MM.1S cells treated with ACY-1215 1 μM and/or BZ 2.5 nM for 12 h were stained with immunofluorescent anti-ubiquitin antibody. BZ-treated cells showed perinuclear structures consistent with aggresome formation, which was disrupted when BZ and ACY-1215 were combined. This result supports the synergistic anti MM activity of ACY-1215 with BZ. We also evaluated the in vivo anti-MM effect of combination therapy using two different xenograft models in SCID mice: plasmacytoma model and disseminated MM model. ACY-1215 in combination with BZ triggered more significant anti-MM activity than either agent alone in suppressing tumor growth and prolonging host survival in both models, without significant adverse effects. To optimize the design of future clinical trials, we conducted pharmacokinetic and pharmacodynamic studies in our plasmacytoma model. ACY-1215 peak plasma levels were observed at 4 h, which were unaffected by the addition of BZ. To further characterize the activity of ACY-1215 against HDAC6 in vivo, we evaluated the acetylation of α-tubulin in mouse blood cells by flow cytometry. The maximum levels of blood cell α-tubulin acetylation were observed at 4 h, providing an important biomarker for future clinical trials. Importantly, levels of acetylated α-tubulin were also detected in tumor tissue from treated mice in a similar time frame to peak blood levels, suggesting that ACY-1215 is readily absorbed by tumor tissue. Moreover, ACY-1215 did not accumulate in tumor tissue, as shown by the decline of acetylated α-tubulin in blood cells and tumor tissue by 24 h post-dose, which parallels the elimination of ACY-1215 from blood. We further confirmed the HDAC6 selectivity of ACY-1215 in our in vivo models by investigating the effect of the drug combination on histone acetylation in tumor tissue. WB analysis and IHC did not show a significant increase in acetylated histone H3 (lys 18), while demonstrating a robust acetylation of α-tubulin, the primary marker of HDAC6 inhibition by ACY-1215 at the cellular level. The results from our in vitro and in vivo studies therefore show significant and synergistic anti-MM activity of ACY-1215 in combination with BZ and provided the rationale for the ongoing phase I/II clinical trial in patients with relapsed or relapsed/refractory MM. Moreover, our pharmacodynamic helped inform the design of correlative studies, which will establish whether acetylated α-tubulin can be used as predictive biomarker of HDAC6 inhibition and disease response. Disclosures: Hideshima: Acetylon: Consultancy. Kung:Acetylon Pharmaceuticals, Inc.: Consultancy. Tamang:Acetylon Pharmaceuticals, Inc.: Employment. Yang:Acetylon Pharmaceuticals, Inc.: Employment. Jarpe:Acetylon Pharmaceuticals, Inc.: Employment. van Duzer:Acetylon Pharmaceuticals, Inc.: Employment. Mazitschek:Acetylon Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees. Ogier:Acetylon Pharmaceuticals, Inc.: Employment. Bradner:Acetylon: Consultancy. Anderson:celgene: Consultancy, Honoraria; Millennium: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Acetylon Pharmaceuticals Inc: founder. Jones:Acetylon Pharmaceuticals, Inc.: Employment. Raje:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Acetylon: Research Funding.

Abstract: Histone deacetylase (HDAC) enzymatic activity has been linked to the transcription of DNA in cancers including multiple myeloma (MM). Therefore, HDAC inhibitors used alone and in combination are being actively studied as novel therapies in MM. In the present study, we investigated the preclinical activity of ACY-1215, an HDAC6-selective inhibitor, alone and in combination with bortezomib in MM. Low doses of ACY-1215 combined with bortezomib triggered synergistic anti-MM activity, resulting in protracted endoplasmic reticulum stress and apoptosis via activation of caspase-3, caspase-8, and caspase-9 and poly (ADP) ribosome polymerase. In vivo, the anti-MM activity of ACY-1215 in combination with bortezomib was confirmed using 2 different xenograft SCID mouse models: human MM injected subcutaneously (the plasmacytoma model) and luciferase-expressing human MM injected intravenously (the disseminated MM model). Tumor growth was significantly delayed and overall survival was significantly prolonged in animals treated with the combination therapy. Pharmacokinetic data showed peak plasma levels of ACY-1215 at 4 hours after treatment coincident with an increase in acetylated α-tubulin, a marker of HDAC6 inhibition, by immunohistochemistry and Western blot analysis. These studies provide preclinical rationale for acetylated α-tubulin use as a pharmacodynamic biomarker in future clinical trials.

Abstract: Abstract 2908 Bone disease in multiple myeloma (MM) is due to the disruption of the delicate balance between osteoblast (OB)-mediated bone formation and osteoclast (OC)-mediated bone resorption. Agents that target both tumor cells and restore normal bone homeostasis can improve long-term disease control and prolong MM patient survival. It has been demonstrated that in vitro pan HDAC inhibitors accelerate OB maturation and suppress OC maturation, while bortezomib triggers OB activation and inhibits osteoclastogenesis. However it has recently been shown that vorinostat (SAHA), a non-selective HDAC inhibitor, causes bone loss in vivo by inhibiting immature OB. Here, we evaluated effects of a selective HDAC6 inhibitor ACY-1215 (Acetylon Pharmaceuticals, Inc), alone and in combination with bortezomib, on MM cell growth and related bone disease. ACY-1215 in combination with bortezomib has synergistic cytotoxicity due to simultaneous inhibition of the proteasome and aggresome pathways. We confirm the in vivo anti-MM activity of ACY-1215 in combination with bortezomib in two different xenograft mouse models: human MM injected subcutaneously; and luciferase-expressing human MM injected intravenously (disseminated MM model). Tumor growth was significantly delayed and overall host survival significantly prolonged in animals treated with combined therapy (34 vs 22 days, n=7, p 〈 0.0011) in plasmacytoma model and (40 vs 17 days, n=12, p 〈 0.0001) in disseminated model. Importantly, we show that ACY-1215 alone and in combination with bortezomib overcomes the proliferative effect of bone marrow stromal cells (BMSCs) and cytokines. MM cells stimulate OC formation and function, while inhibiting OB differentiation via both cell-to-cell contact and cytokine secretion. Therefore, osteoclastogenesis is an important therapeutic target in MM. In this context, we evaluated the effect of ACY-1215 (1μM) and bortezomib (2.5nM) on OCs generated from blood mononuclear cells stimulated with receptor activator of nuclear factor kappa B ligand (RANKL). ACY-1215 alone and in combination with bortezomib inhibited OC differentiation, evidenced by a decreased number of TRAP positive multinucleated cells and bone-resorbing activity. In addition, ACY-1215 (1μM) significantly decreased cell growth of mature OC in co-culture with MM cell lines. We next examined the effect of ACY-1215, alone and in combination with bortezomib, on downstream targets in RANKL/RANK signaling. ACY-1215 plus bortezomib inhibits transcription factors implicated in OC differentiation including p-ERK, p-AKT, c-FOS and NFATC1. Since there is decreased OB function and new bone formation in MM, we next assessed the effect of ACY-1215 on OB differentiation. ACY-1215, alone and in combination, enhanced OB differentiation, evidenced by increased alkaline phosphatase enzyme activity and alizarin red staining. In addition, we show increased mRNA expression of b-catenin, osteocalcin, Runx2 and Sp7 (OB differentiation markers) in immature OB triggered by ACY-1215. Finally, ACY-1215 was not toxic to PHA stimulated PBMCs, suggesting a favorable side effect profile and therapeutic index. Our studies therefore demonstrate that ACY-1215, alone and in combination with bortezomib, can inhibit osteoclastogenesis enhance osteoblastogenesis, and inhibit MM cell growth. Based upon these studies, ongoing clinical trials are examining the efficacy of ACY-1215 in relapsed MM and associated bone disease. Disclosures: Hideshima: Acetylon: Consultancy. Kung:Acetylon Pharmaceuticals, Inc.: Consultancy. Tamang:Acetylon Pharmaceuticals, Inc.: Employment. Yang:Acetylon Pharmaceuticals, Inc.: Employment. Jarpe:Acetylon Pharmaceuticals, Inc.: Employment. van Duzer:Acetylon Pharmaceuticals, Inc.: Employment. Mazitschek:Acetylon Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees. Bradner:Acetylon Pharmaceuticals, Inc.: Consultancy. Anderson:Millennium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acetylon Pharmaceuticals, Inc.: founder; Merck: Membership on an entity's Board of Directors or advisory committees. Jones:Acetylon Pharmaceuticals, Inc.: Employment. Raje:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Acetylon: Research Funding.