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Supplementary methods Supplementary Tables S1-S6 Supplementary Figure legends for SF1-SF11 Supplementary Table S1. Primers used for qRT-PCR Supplementary Table S2. Primers used for pyrosequencing Supplementary Table S3. IC50 values for CDDP resensitization by SGI-110 and 5-aza-dC in vitro Supplementary Table S4. Relative induction of MLH1 mRNA levels in response to SGI-110 Supplementary Table S5. Candidate drivers of OC CDDP Resistance Supplementary Table S6. Relative induction of ZIC1 mRNA levels in response to SGI-110

Purpose: To investigate SGI-110 as a “chemosensitizer” in ovarian cancer and to assess its effects on tumor suppressor genes (TSG) and chemoresponsiveness-associated genes silenced by DNA methylation in ovarian cancer.Experimental Design: Several ovarian cancer cell lines were used for in vitro and in vivo platinum resensitization studies. Changes in DNA methylation and expression levels of TSG and other cancer-related genes in response to SGI-110 were measured by pyrosequencing and RT-PCR.Results: We demonstrate in vitro that SGI-110 resensitized a range of platinum-resistant ovarian cancer cells to cisplatin (CDDP) and induced significant demethylation and reexpression of TSG, differentiation-associated genes, and putative drivers of ovarian cancer cisplatin resistance. In vivo, SGI-110 alone or in combination with CDDP was well tolerated and induced antitumor effects in ovarian cancer xenografts. Pyrosequencing analyses confirmed that SGI-110 caused both global (LINE1) and gene-specific hypomethylation in vivo, including TSGs (RASSF1A), proposed drivers of ovarian cancer cisplatin resistance (MLH1 and ZIC1), differentiation-associated genes (HOXA10 and HOXA11), and transcription factors (STAT5B). Furthermore, DNA damage induced by CDDP in ovarian cancer cells was increased by SGI-110, as measured by inductively coupled plasma-mass spectrometry analysis of DNA adduct formation and repair of cisplatin-induced DNA damage.Conclusions: These results strongly support further investigation of hypomethylating strategies in platinum-resistant ovarian cancer. Specifically, SGI-110 in combination with conventional and/or targeted therapeutics warrants further development in this setting. Clin Cancer Res; 20(24); 6504–16. ©2014 AACR.

Supplementary Figure S1. Diagrams of biweekly and QD5 drug (SGI-110 and CDDP) treatment schedules for mice. (A). For non-tumor bearing mice study, mice (3 per group) were injected with different doses of SGI-110 (2 mg/kg, 5 mg/kg, s.c.), CDDP (2 mg/kg, 4 mg/kg, i.p.) or in combination of the 2 drugs. The treatment was performed in 2 schedules as shown. (B). For A2780 tumor bearing mice study, mice (5 per group) were injected with OC cells subcutaneously on the right flanks, and followed by different doses of SGI-110 (2 mg/kg, s.c.), CDDP (2 mg/kg, 4 mg/kg, i.p.) or in combination of the 2 drugs after a palpable tumor was formed on each mouse. The treatment was performed in 2 schedules as shown. Blood samples were collected on the indicated days. Supplementary Figure S2. 5-aza-dC treatment modulates CDDP sensitization and alters DNA methylation and gene expression in vitro. Comparison of cell growth rates of parental A2780 cells (A), A2780-CDDP resistant cells (B), and CP70 CDDP resistant cells (C) treated with 5μM 5-aza-dC, or vehicle (DMSO 1:2000) for 48 hours followed by CDDP ranging from 0-50μM CDDP. Mean values {plus minus} S.E.M. of 8 independent experiments in duplicate are reported. All treatments were significantly different, at P < 0.05, than vehicle control cells. IC50 values are listed in Supplementary Table S2. Data shown represent means {plus minus} S.E.M. from 8 experiments. Supplementary Figure S3. SGI-110 treatment alters DNA methylation in vitro. Parental A2780 cells, A2780-CDDP resistant cells, and CP70-CDDP resistant cells were treated with 5 μM SGI-110 for 48 hours, and DNAs were extracted for pyrosequencing analysis for specific genes (AKT1S1: subunit of mTORC1; HOXA10: embryonic development; IFNAR1 and IL2RG: receptor subunit in Jak/STAT pathway; AKT1: serine/threonine kinase in apoptosis; BRCA1: DNA repair; STAT5B: transcription factor; LRP6; AXIN1: cytoplasmic G-protein signaling regulator; CTNNB1: β-catenin; and CSKN1D: casein kinase). Supplementary Figure S4. 5-aza-dC and SGI-110 treatment modulated CDDP sensitization. Cells were treated with 0.1 μM SGI-110, 0.3 μM SGI-110 or DMSO (control) for 3-consecutive days, prior to treatment with a range of CDDP and cell viability determined on day 8 using the alamar blue assay. IC50s are shown in the boxes under each graph. Data shown represent means {plus minus} S.E.M. from three independent experiments. Supplementary Figure S5. Effects of SGI-110 on MLH1 expression levels in OC cell lines. Cells were treated for 3-consecutive days with 0.1 μM SGI-110, 0.3 μM SGI-110, 1 μM SGI-110 or DMSO (control) and expression levels of MLH1 determined. (A). Western blot analysis of MLH1 expression in A2780 cells. (B). Western blot analysis of MLH1 expression in OAW28 and OVCAR8 cells. Supplementary Figure S6. SGI-110 induces the expression of potential CDDP-resistance biomarkers in OAW28. OAW28 cells were treated for 3-consecutive days with 0.1 μM SGI-110, 0.3 μM SGI-110, 1 μM SGI-110 or DMSO (control) and mRNA levels of 19 genes determined by RT-PCRFold change in mRNA levels were calculated as 2(-ΔΔCT) relative to DMSO-treated cells. Of the 19 genes analyzed (Supplementary Table S4), only genes for which there was a significant difference (P< 0.05) in expression levels between SGI-110 and DMSO-treated cells are included in the figure. Data shown represents means {plus minus} S.E.M. from triplicate experiments. Supplementary Figure S7. SGI-110 is well tolerated in non-tumor bearing mice. Mice were treated as Supplemental Figure S1A and were measured for BW twice a week. (A). BW curves for QD5 schedule: 8-day treatment followed by a 4-week recovery. 5 mice were sacrificed on Day 8 to Day 10 (2 mice in SGI-110 5 mg/kg; 2 mice in SGI-110 5 mg/kg + cisplatin 2 mg/kg; 1 mouse in SGI-110 5 mg/kg + cisplatin 4 mg/kg). (B). BW curves for biweekly schedule: 4 treatment cycles (7 days a cycle) followed by a 3-week recovery. Data shown represent means {plus minus} S.E.M. from 5 mice. Supplementary Figure S8. Decreased tumor growth from parental-derived A2780 xenografts treated with SGI-110 and CDDP in the QD5 and biweekly regimens. CDDP-resistant A2780 xenograft tumor volume was compared among single agent and combination treatment to vehicle control in two treatment schedules. (*: P

Worldwide, Head and Neck Squamous Cell Carcinomas (HNSCC) account for about 900,000 cases and 400,000 deaths. In some settings, like Fanconi anemia (FA), patients receive curative treatments (allogeneic stem cell transplantation), only to develop HNSCC in early adulthood at a high rate of incidence. Current treatment strategies for non-FA HNSCC patients include surgery, chemotherapy and radiotherapy. However, these are not viable treatment options for FA HNSCC patients due to their low tolerance for the high toxicity levels of chemotherapy and radiation. Therefore, there is a critical need for novel and targeted therapeutic interventions for the treatment of FA HNSCC patients. B7H3, a checkpoint member of the B7 and CD28 families, is overexpressed on several solid tumors but is absent or not expressed on healthy tissues. It is a promising target for immunotherapy, and recent basket trials, particularly in the prostate cancer, have demonstrated strong clinical signals. Here we developed and tested the ability of GTB-5550, a tri-specific killer engager (TriKE) that includes a B7H3 targeting component, to direct NK cell killing to B7H3-expressing Head and Neck cancer targets. This TriKE molecule includes an NK cell engaging domain containing a humanized camelid nanobody against CD16, a camelid nanobody against B7H3 and a wild type IL-15 sequence between the two engagers. We assessed B7H3 expression by flow cytometry of wild-type HNSCC cells and a paired version with a CRISPER KO of the FANCA gene and determined that the KO had no effect on B7H3 expression. Thus, GTB-5550 activity against HNSCC should be present on both normal HNSCC and FA-HNSCC settings. NK cell responses against HNSCC lines in the presence of GTB-5550 were assessed through either flow cytometry based functional assays, to evaluate NK cell degranulation and cytokine secretion, or IncuCyte imaging assays, to directly assess target killing. NK cell degranulation and IFN-gamma production of GTB-3550-treated samples were higher compared to that of control samples treated with B7H3 single domain or IL-15 alone. GTB-5550 also induced more HNSCC target cell killing by NK cells compared to treatment with the B7H3 single domain or IL-15 alone irrespective of the FANCA gene. Ongoing experiments will evaluate functionality of GTB-5550 on FA patient samples as well as in spheroid assays. Taken together, this data shows that a GTB-5550 is able to drive NK cell activity against B7H3-expressing HNSCC cells, which presents potential for a B7H3-targeted TriKE to be used to be implemented clinically to treat HNSCC or FA-HNSCC patients. Citation Format: Melissa Khaw, Zachary Davis, Nicholas Zorko, Greg Berk, Gavin Choy, Margaret MacMillan, Martin Felices, Jeffrey S. Miller. GTB-5550 (cam16-IL15-camB7H3) trispecific killer engager (TriKE®) drives natural killer cell activation and antibody dependent cellular cytotoxicity against head and neck squamous cell carcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3435.

e15125 Background: APL-501 is a humanized monoclonal antibody targeting programmed cell death-1 (PD-1). APL-501 is being evaluated in patients (pts) with advanced recurrent and relapsed solid tumors who had not been previously treated with an immune checkpoint inhibitor in an ongoing 3-part Phase 1 trial (NCT03053466). Herein, we present the emerging pharmacokinetic (PK) and receptor occupancy (RO), safety and preliminary efficacy. Methods: Weight-based dose escalation (1, 3, and 10 mg/kg, Part 1) and Extension (Part 2) has been completed and the study is currently enrolling specific tumor types (MSI-H/dMMR and Carcinoma of Unknown Primary [CUP]) into the Expansion Cohorts (Part 3). Relapsed/refractory solid tumor pts were enrolled in Part 1 and Part 2. Key exclusion criteria included prior therapy targeting PD-1/PD-L1 and uncontrolled CNS metastases. APL-501 was administered IV over 1 hour every 14 days. Serum and PBMCs were collected for PK and RO analysis, respectively. RO was assessed using different T-cell markers measured by flow cytometry of PBMC. Anti-tumor activity was assessed by investigators using RECIST and irRECIST. Safety was assessed using CTCAE, v4.03. Results: As of 31 Dec 2019, 22 pts were enrolled with a mean age of 62.1 (SD: 12.2) years. ECOG PS 0/1 reported at 10/12 pts, respectively. Pts had a median number of 3 prior lines of therapy (range, 1 – 9) and median time to treatment from initial diagnosis was 30.1 months (range, 6.7 – 184.8). Across doses evaluated, APL-501 demonstrated dose proportional PK. One hundred percent (100%) RO was observed across all doses evaluated. No dose limiting toxicities were reported. Fifteen pts (68.2%) had related AEs; two pts (9.1%) had Grade ≥ 3 related AEs to APL-501. Eight pts had stable disease and two pts had partial response by RECIST (esophageal adenocarcinoma and CUP). Seven pts remained on therapy for ≥ 24 weeks. The recommended phase 2 dose (RP2D) has been determined to be 400 mg IV every 14 days (non-weight-based) based on safety and PK modeling. Conclusions: Preliminary results indicate clinical activity of APL-501 in relapsed/refractory malignant disease with a generally tolerable safety profile. The PK and RO profile, across all doses evaluated, appears comparable to marketed PD-1 inhibitors. Continued exploration of APL-501 with the RP2D in CUP and MSI-H/dMMR tumors is being planned. Clinical trial information: NCT03053466 .

Amuvatinib is an oral multi-kinase inhibitor that suppresses RAD51, inhibits mutant c-KIT and platelet-derived growth factor receptor alpha, and has synergistic activity with DNA-damaging agents and topoisomerase inhibitors such as etoposide, doxorubicin, and topotecan. We conducted a phase 1B study to estimate the maximum tolerated dose (MTD) levels of amuvatinib with standard chemotherapy regimens and to define the safety profiles of specific amuvatinib + standard regimens.Five therapies each co-administered with amuvatinib 100-800 mg/day every 21 days were evaluated in treatment-naïve or moderately pre-treated subjects: paclitaxel IV followed by carboplatin IV; carboplatin IV followed by etoposide; topotecan IV; docetaxel IV; and erlotinib by mouth.Among 97 treated subjects, no treatment arm reached the MTD. Dose-limiting toxicities included febrile neutropenia and diarrhea. No pharmacokinetic interactions of amuvatinib with any cancer regimens occurred. Of 12/97 (12 %) partial responses overall, 11 were seen in the amuvatinib and paclitaxel/carboplatin or carboplatin/etoposide arms and most commonly in the neuroendocrine (NE), non-small cell lung cancer (NSCLC), and small cell lung cancer (SCLC) tumors. Forty-four subjects (45 %) had stable disease. Adverse events reflected combination treatment and were primarily non-hematologic (fatigue, alopecia, diarrhea, nausea, anorexia) and hematologic (neutropenia, anemia, thrombocytopenia, leukopenia). Pharmacodynamic effects as measured by decreased levels of RAD51 and increased residual DNA damage (53BP1 foci) were seen in skin punch biopsies.Amuvatinib was well tolerated, modulated RAD51, and showed antitumor activity when combined with paclitaxel/carboplatin and carboplatin/etoposide in NE, NSCLC, and SCLC tumors.

SGI-110 is a second-generation hypomethylating prodrug whose active metabolite is the well-characterized drug decitabine. This novel compound is an oligonucleotide consisting of decitabine linked through a phosphodiester bond to the endogenous nucleoside deoxyguanosine. The dinucleotide configuration provides protection from drug clearance by deamination, while maintaining at least equivalent effects on gene-specific and global hypomethylation both in vitro and in animal model systems. This agent is currently being tested in phase I and II clinical trials in humans and has been demonstrated to be safe and well tolerated as a single agent, with evidence of promising activity in heavily pretreated (including currently FDA approved hypomethylating drugs) myelodysplastic syndrome and acute myeloid leukemia patients. Ongoing trials are also open in platinum-resistant ovarian cancer and hepatocellular carcinoma.

Amuvatinib is a novel orally administered tyrosine kinase inhibitor with in vitro pharmacological activity against mutant KIT, platelet-derived growth factor receptor alpha (PDGFRα), and Rad51. Amuvatinib was investigated in a first-in-human, single-agent, phase I, accelerated titration, dose-escalation trial ( clinicaltrials.gov identifier: NCT00894894) in patients with solid tumors refractory to prior therapies or for which no standard therapy existed. Twenty-two patients received amuvatinib dry powder capsules (DPC) from 100 to 1,500 mg daily in 28-day cycles. Safety, preliminary efficacy, pharmacologic activity, and pharmacokinetics were investigated. No dose-limiting toxicities were reported with amuvatinib DPC up to 1,500 mg/day, given as one or in divided doses, for 1–6 cycles. No maximum tolerated dose was reached. Five patients had serious adverse events, all unrelated to treatment. Exposure levels were low and variable. One gastrointestinal stromal tumor (GIST) patient who previously failed imatinib and sunitinib had a 2–[18F]fluoro-2-deoxyglucose positron emission tomography response and clinical stable disease. A second GIST patient had decreased Rad51 expression in a skin punch biopsy on days 15 and 29. Amuvatinib shows in vitro inhibitory activity against multiple human tyrosine kinases including mutant KIT and PDGFRα and in vivo activity in human xenograft models in mice. Amuvatinib is also active as a DNA repair protein Rad51 inhibitor following chemotherapy. In this study, the amuvatinib DPC formulation was well tolerated up to 1,500 mg/day. While exposures were low and variable, a transient response in a refractory GIST patient warrants further investigation into single-agent amuvatinib in refractory GIST.

Amuvatinib is a multi-targeted tyrosine kinase inhibitor with activity that also disrupts DNA damage repair through suppression of homologous recombination protein Rad51. Amuvatinib dry-powder capsules (DPC) showed evidence of activity in early Phase 1 cancer studies but low systemic exposure. The purposes of the studies were to investigate the cause of low exposure, develop, and test an alternative formulation with improved exposure, and establish the dose to be tested in future studies in cancer patients. Three studies were conducted in a total of 58 healthy subjects: a food-effect study using amuvatinib DPC, a single-dose pharmacokinetic study comparing amuvatinib DPC to a new lipid-suspension capsules (LSC), and a multiple-dose pharmacokinetic study using amuvatinib LSC. A high-fat meal administered with amuvatinib DPC increased the rate and extent of absorption compared to the Fasted state, a 183 and 118% increase in the mean C max and AUC0–∞ of amuvatinib, respectively. The single-dose pharmacokinetics of amuvatinib LSC resulted in an approximately two-third-fold increased exposure (AUC) compared with amuvatinib DPC. The multiple-dose pharmacokinetics of the amuvatinib LSC 300 mg administered every 8 h exhibited improved accumulation compared with the 12-h regimens and achieved presumed therapeutic level safely with no serious or severe adverse events reported. No subject discontinued treatment due to an adverse event. Amuvatinib LSC, 300 mg every 8 h, is being studied in cancer patients based on the improved exposure and similar safety profile to amuvatinib DPC. A lipid-based formulation approach may be a useful tool for other low aqueous soluble compounds.

e11609 Background: Current therapies targeting HER2 neuprotein expression are effective for breast tumors (CaB) with high expression levels (IHC 3+). However, most breast tumours exhibit low to int...

Ovarian cancer stem cells (OCSCs) are associated with drug resistance and tumor relapse. Epigenetic aberrations, especially DNA methylation, result in silencing of tumor suppressor and differentiation-associated genes and regulate OCSCs' survival. To test the hypothesis that DNA hypomethylating agents can “reset” OCSCs towards differentiation, we investigated the effect of the DNA methytransferase inhibitor SGI-110 on OCSCs, defined by aldehyde dehydrogenase 1 (ALDH)(+) cells. We treated ALDH(+) cells from platinum-sensitive A2780 and platinum-resistant A2780-cp OC cells with SGI-110 (100nM, 72 hr) or with cisplatin (CDDP; 1.67M, 24hr). After a 4 day recovery period, %ALDH+ was analyzed using FACS, cell viability was determined, and ALDH(+) cells were grown as spheroids in culture or as xenografts in mice. The overall %ALDH+ cells was higher (P Citation Format: Yinu Wang, Horacio Cardenas, Fang Fang, Salvatore Condello, Pietro Taverna, Gavin Choy, Mohammad Azab, Kenneth Nephew, Daniela Matei. SGI-110 alters ovarian cancer stem cells to prevent recurrent and chemoresistant ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2317. doi:10.1158/1538-7445.AM2014-2317

Background: Epigenetic changes have been implicated in acquired resistance to platinum. SGI-110 is a second generation SQ HMA with improved pharmaceutical properties compared to decitabine. Here we report the clinical results and pharmacodynamic analyses of the phase 1 study of SGI-110 in combination with carboplatin in patients with recurrent platinum resistant high-grade serous, epithelial ovarian cancer (EOC), primary peritoneal carcinoma (PPC) or fallopian tube (FT) cancer. Methods: SGI-110 was administered SQ QD x 5 followed by carboplatin IV on Day 8 of a 28-day cycle. Patients were required to have either measurable disease according to RECIST v1.1 or detectable disease (modified Rustin) with clinical response assessed using the applicable criteria. Safety assessments were graded using CTCAE v4. Results: Twenty patients (18 EOC, 1 PPC, 1 FT) were enrolled and treated in the phase 1 portion of the trial. Median age was 55.8 years (38-72); ECOG PS of 0/1/2 was 10/10/0, respectively. Median number of prior regimens was 7 (1-9). The starting doses were SGI-110 45 mg/m2 SQ QD x 5 and carboplatin AUC5 in the first cohort of 6 patients. Four DLTs of myelosuppression (neutropenia and thrombocytopenia) in the first cohort led to dose reduction to SGI-110 30 mg/m2 and carboplatin AUC4 with granulocyte-CSF permitted at the discretion of the physician. No DLTS were observed in 14 patients and this dose was recommended for the subsequent phase 2 study. Grade 3/4 AEs regardless of relationship to the combination ≥ 10% included anemia, leukopenia, neutropenia, thrombocytopenia, nausea, vomiting, constipation, small intestinal obstruction, infusion related reaction and pulmonary embolism. Three PRs and 9 SDs as best response were observed in 20 patients for an overall response rate and clinical benefit rate of 15% and 60%, respectively. All PRs and 3 SDs were accompanied by CA-125 decrease. LINE-1 hypomethylation, a marker of global DNA methylation, was recorded in PBMCs with SGI-110 30 mg/m2 (avg: -19.5%, n=14) and 45 mg/m2 (avg: -17.4%, n=6). Gene specific methylation of RASSF1A and BRCA-1 measured by pyrosequencing was significantly decreased at C2D8 compared to baseline in paired tumor biopsies/ascites (n=9). Gene re-expression measured by quantitative RT-PCR was observed in tumor biopsies. Conclusions: Priming treatment with SGI-110 prior to carboplatin induced clinical responses in a heavily-pretreated platinum resistant ovarian cancer population with expected and manageable safety profile. Potent LINE-1 demethylation and demethylation and re-expression of silenced tumor genes were recorded. The phase 2 portion of the trial is currently ongoing with patients randomized to either the RP2D dose combination or a physician choice of 1 of 4 treatment options (topotecan; liposomal doxorubicin; weekly paclitaxel; or weekly gemcitabine). Citation Format: Gini Fleming, Sharad Ghamande, Yvonne Lin, Angeles Alvarez Secord, John Nemunaitis, Merry-Jennifer Markham, Kenneth Nephew, Fang Fang, Shweta Gupta, Sue Naim, Gavin Choy, Simone Jueliger, Pietro Taverna, Yong Hao, Harold Keer, Mohammad Azab, Daniela Matei. Clinical epigenetic resensitization of platinum-resistant, recurrent ovarian cancer patients with SGI-110, a novel, second-generation, subcutaneously administered hypomethylating agent (HMA). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2320. doi:10.1158/1538-7445.AM2014-2320

7030 Background: SGI-110 is a novel HMA administered as a small volume injection which results in extended decitabine exposure. We previously reported an Overall Complete Remission (OCR=CR+CRi+CRp)...

Background SGI-110 is a second generation HMA formulated as a dinucleotide of decitabine (DAC) and deoxyguanosine. The compound is delivered as a small volume, pharmaceutically stable subcutaneous (SQ) injection which allows longer half-life and more extended DAC exposure than DAC intravenous infusion. This pharmacokinetic profile offers the potential for improved biological and clinical activity and safety over currently available HMAs (Kantarjian et al. ASH, 2012). Methods A randomized Phase 1-2 first-in-human PK/PD-guided, dose-escalation study was conducted in patients with relapsed or refractory intermediate or high-risk MDS or AML. Patients were initially randomized to one of two SQ regimens - Dailyx5 or Weeklyx3, for 28-day courses. Subsequently, a Twice Weeklyx3 regimen (Monday, Thursday) was added for evaluation based on emerging LINE-1 demethylation data from the Weeklyx3 regimen. Results 93 patients (74 AML, 19 MDS) were treated in the dose escalation phase: 44, 34, and 15 patients were treated in the Dailyx5, Weeklyx3, and the Twice Weeklyx3 regimens, respectively. Across the three regimens, median age was 70 years (range, 29–86), 68% male, and 87% had ECOG PS of 0-1. The median number of prior regimens was 3 (range, 1–9) and 68% of patients had prior HMA treatment (59% AML, and 100% MDS). Of the 74 AML patients treated, 31 (42%) had secondary AML including antecedent MDS. Patients received a median of 2 courses of SGI-110 (range, 1-20). LINE-1 demethylation data at the 2 highest dose levels which were well tolerated and evaluated for all 3 regimens (60 and 90 mg/m2) are shown in the figure below. The Dailyx5 regimen demonstrated the most potent average LINE-1 demethylation, while the Twice Weeklyx3 achieved the most prolonged LINE-1 demethylation. The least potent demethylation was seen with the Weeklyx3 regimen. There was no additional demethylation at the 90 mg/m2 dose compared to 60 mg/m2in all 3 regimens. Responses were reported according to the IWG Criteria 2006 (MDS)/2003 (AML). Complete remissions were observed in 5 AML patients (2CRs, 1CRp, and 2CRi). Clinical responses (2 mCR and 3 HI-E, 1 HI-N, 1 HI-P) were observed in 6 MDS patients, all of whom had been previously treated with HMA. All AML responses and both mCR in MDS patients achieved ≥10% LINE-1 demethylation. Safety is reported based on Adverse Events (AEs) as graded by the CTCAE v4 criteria. Across regimens, the Twice Weeklyx3 demonstrated an increased number of related AEs compared to the other regimens. The most commonly reported related AEs ≥ 10% in the Dailyx5 regimen (injection site pain, thrombocytopenia, neutropenia, anemia, fatigue), Weeklyx3 regimen (injection site pain and diarrhea), and Twice Weeklyx3 regimen (injection site pain, injection site reaction, fatigue, dizziness, febrile neutropenia, neutropenia, anemia, and thrombocytopenia). Conclusions SQ SGI-110 is a potent HMA using all 3 regimens evaluated. The most potent hypomethylation was achieved with Dailyx5 dosing and the most prolonged hypomethylation was achieved using the Twice Weeklyx3 regimen. All 3 regimens were well tolerated. Clinical responses were observed in heavily pretreated patients, including those with prior HMA exposure. These results support the ongoing Phase 2 expansion study investigating the Dailyx5 dosing schedule in patients with MDS and AML who are either HMA treatment naïve or previously treated with HMAs. Disclosures: Roboz: Astex Pharmaceuticals, Inc.: Honoraria, Research Funding. Issa:Astex Pharmaceuticals Inc.: Honoraria, Research Funding. Rizzieri:Astex Pharmaceuticals, Inc.: Research Funding. Stock:Astex Pharmaceuticals, Inc.: Research Funding. O'Connell:Astex Pharmaceuticals, Inc.: Research Funding. Yee:Astex Pharmaceuticals, Inc.: Research Funding. Tibes:Astex Pharmaceuticals, Inc.: Research Funding. Griffiths:Astex Pharmaceuticals, Inc.: Research Funding. Walsh:Astex Pharmaceuticals, Inc.: Research Funding. Feldman:Astex Pharmaceuticals, Inc.: Research Funding. Ritchie:Astex Pharmaceuticals, Inc.: Research Funding. Rao:Astex Pharmaceuticals, Inc.: Research Funding. Larson:Astex Pharmaceuticals, Inc.: Research Funding. Garcia-Manero:Astex Pharmaceuticals, Inc.: Research Funding. Ravandi:Astex Pharmaceuticals, Inc.: Research Funding. Jabbour:Astex Pharmaceuticals, Inc.: Research Funding. Cortes:Astex Pharmaceuticals, Inc.: Research Funding. Schimmer:Astex Pharmaceuticals, Inc.: Research Funding. Mesa:Astex Pharmaceuticals, Inc.: Research Funding. Blum:Astex Pharmaceuticals, Inc.: Research Funding. Chung:Astex Pharmaceuticals Inc.: Research Funding. Naim:Astex Pharmaceuticals, Inc.: Employment. Taverna:Astex Pharmaceuticals Inc.: Employment. Hao:Astex Pharmaceuticals Inc.: Employment. Choy:Astex Pharmaceuticals, Inc.: Employment. Azab:Astex Pharmaceuticals Inc.: Employment. Kantarjian:Astex Pharmaceuticals, Inc.: Research Funding.

Background SGI-110 is second generation HMA formulated as a dinucleotide of decitabine (DAC) and deoxyguanosine delivered as a small volume, pharmaceutically stable SQ injection allowing longer half-life and more extended decitabine exposure than DAC IV infusion. SGI-110 differentiated pharmacokinetic profile resulted in potent hypomethylation and clinical responses in previously treated MDS and AML patients in the phase 1 trial (Kantarjian et al. 2012). Methods In a randomized Phase 2 study, relapsed/refractory AML, or elderly treatment naïve AML patients who were not suitable for induction chemotherapy (poor major organ function; poor cytogenetics; or secondary AML) were randomized to one of two SQ doses – the biologically effective dose (BED) of 60 mg/m2 QDx5 or 90 mg/m2 QDx5. The primary endpoint of the phase 2 study is the overall remission rate (CR, CRi, and CRp) based on the International Working Group Criteria 2003. Safety findings based on adverse events (AEs) as graded by the CTCAE v4 criteria and pharmacodynamic data on Long Interspersed Nucleotide Element (LINE-1) DNA methylation (an index of global DNA methylation) activity were also assessed and reported. Results As of June 30, 2013, sixty-seven patients (50 relapsed/refractory AML, 17 treatment naïve elderly AML) were treated and had a minimum follow up of 3 months. Patients were randomized to either 60 mg/m2 dose (32 patients) or 90 mg/m2 dose (35 patients). The median age was 66 years (range, 22–84), 69% were male, and ECOG PS of 0/1/2 was reported in 11/47/9 patients respectively. Median number of prior regimens was 2 (range, 0–10). Patients’ characteristics were well balanced between the 2 dose groups. The primary endpoint of overall remissions (CR, CRp, or CRi) was observed in 17/67 patients (25% with 95% CI, 16–37%). There were 8 complete remissions (CR, CRp, or CRi) in 50 patients with relapsed/refractory AML (16% with 95% CI, 7-29%); and 9 complete remissions (CR, CRp, or CRi) in 17 treatment-naïve elderly AML patients (53% with 95% CI, 28-77%). Five patients (4 relapsed/refractory, and one treatment-naïve elderly AML) subsequently received a stem cell transplant. There was no difference in the complete remission rate between 60 and 90 mg/m2 doses (8 remissions in 32 patients at 60 mg/m2, and 9 remissions in 35 patients at 90 mg/m2). LINE-1 DNA methylation data before and after treatment was available in 50 (75%) patients enrolled. LINE-1 demethylation ≥ 10% post treatment was observed in 83% and 78% in the 60 mg/m2 and 90 mg/m2, respectively. The median maximum LINE-1 demethylation for responders is 25% as compared to 19% for non-responders. The most common adverse events (AEs) regardless of relationship to SGI-110 ≥ Grade 3 include febrile neutropenia, thrombocytopenia, anemia, leukopenia, neutropenia, and pneumonia. The 90 mg/m2 dose showed a greater frequency of Grade 3/4 related AEs ≥ 10% (anemia, febrile neutropenia, leukopenia, neutropenia, and thrombocytopenia) compared to the 60 mg/m2 dose. Conclusions SQ SGI-110 is a new HMA which is well tolerated and clinically active in the treatment of AML. Complete remissions and potent demethylation of ≥10% were equally observed at the 2 dose groups of 60 and 90 mg/m2. These data support further phase 3 investigation of this agent in the treatment of AML. Preliminary overall remission rate of 53% in treatment-naïve elderly AML seems to compare favorably with previous results reported for HMA treatment but this needs to be confirmed in a larger number of patients and randomized studies. Disclosures: Kantarjian: Astex Pharmaceuticals, Inc.: Research Funding. Jabbour:Astex Pharmaceuticals, Inc.: Research Funding. Yee:Astex Pharmaceuticals, Inc.: Research Funding. Kropf:Astex Pharmaceuticals, Inc.: Research Funding. O'Connell:Astex Pharmaceuticals, Inc.: Research Funding. Stock:Astex Pharmaceuticals, Inc.: Research Funding. Tibes:Astex Pharmaceuticals, Inc.: Research Funding. Rizzieri:Astex Pharmaceuticals, Inc.: Research Funding. Walsh:Astex Pharmaceuticals, Inc.: Research Funding. Griffiths:Astex Pharmaceuticals, Inc.: Research Funding. Roboz:Astex Pharmaceuticals, Inc.: Honoraria, Research Funding. Savona:Astex Pharmaceuticals, Inc.: Research Funding. Ervin:Astex Pharmaceuticals, Inc.: Research Funding. Podoltsev:Astex Pharmaceuticals, Inc.: Research Funding. Pemmaraju:Astex Pharmaceuticals, Inc.: Research Funding. Daver:Astex Pharmaceuticals, Inc.: Research Funding. Garcia-Manero:Astex Pharmaceuticals, Inc.: Research Funding. Borthakur:Astex Pharmaceuticals, Inc.: Research Funding. Wierda:Astex Pharmaceuticals, Inc.: Research Funding. Ravandi:Astex Pharmaceuticals, Inc.: Research Funding. Cortes:Astex Pharmaceuticals, Inc.: Research Funding. Brandwein:Astex Pharmaceuticals, Inc.: Research Funding. Odenike:Astex Pharmaceuticals, Inc.: Research Funding. Feldman:Astex Pharmaceuticals, Inc.: Research Funding. Chung:Astex Pharmaceuticals Inc.: Research Funding. Naim:Astex Pharmaceuticals, Inc.: Employment. Choy:Astex Pharmaceuticals, Inc.: Employment. Taverna:Astex Pharmaceuticals, Inc.: Employment. Hao:Astex Pharmaceuticals Inc.: Employment. Dimitrov:Astex Pharmaceuticals, Inc.: Employment. Azab:Astex Pharmaceuticals, Inc.: Employment. Issa:Astex Pharmaceuticals, Inc.: Consultancy, Research Funding.

Aberrant DNA hypermethylation favors tumor escape from host’s immune recognition by decreasing the expression of tumor-associated antigens (TAA) (e.g., cancer testis antigens (CTA)), HLA, co-stimulatory molecules that are all required for efficient immune recognition of cancer cells. Thus, increased levels of DNA methylation in cancer cells might contribute to reduced clinical efficacy of immunotherapeutic approaches. SGI-110 is a dinucleotide of decitabine (DAC) and deoxyguanosine formulated as a low volume SQ injection which in the clinic, provides more extended DAC exposure compared to DAC IV. The observed superior PK profile offers the potential of improved biological and clinical activity with a better safety profile compared to currently available hypomethylating agents. We recently demonstrated that SGI110 induced/up-regulated CTA expression in cancer cells of different histotype at both mRNA and protein levels. Quantitative methylation-specific PCR analyses identified hypomethylation of MAGE-A1 and NY-ESO-1 promoters in SGI-110-treated cancer cells, demonstrating a direct role of pharmacologic DNA demethylation in CTA expression. SGI-110 also up-regulated the expression of HLA class I and ICAM-1, resulting in an improved recognition of cancer cells by TAA-specific CTL. These immunomodulatory properties of SGI-110 are further supported by in vivo findings with human melanoma xenografts. Furthermore, preliminary data, generated in a syngeneic model of murine cancer, demonstrate the synergistic anti-tumor effectiveness of SGI-110 when administered in combination with immunostimulatory antibodies (i.e., anti-CTLA-4 and -PD-1). These findings were extended to the clinical setting, where the hypomethylating activity of SGI-110 on CTA-specific promoters and the resulting induction/ up-regulation of NY-ESO-1, MAGE-A1, MAGE-A3 expression were characterized in PBMC from MDS or AML patients. Together, these preclinical and clinical data suggest that SGI-110 in addition to having direct anti-tumor activity as a single agent may sensitize tumor cells to agents acting through the immune system and hence it may increase their clinical activity. These evidences, together with the favorable pharmacologic and pharmacokinetic features of SGI-110, provide a strong scientific rationale to develop new anti-cancer therapies based on the combined efficacy of SGI-110 and immunotherapeutic strategies.

Women with advanced stage ovarian cancer (OC) have a five-year survival rate of less than 25%. Although most patients respond to platinum-based chemotherapy, relapses are common, leading to platinum-resistant OC, which is uniformly fatal. OC progression is associated with accumulation of epigenetic alterations. In particular, deoxycytosine methylation of CpG islands in promoter regions of tumor suppressor genes (TSGs) plays a prominent role in the development and progression of drug-resistant epithelial OC. We recently demonstrated for the first time in a clinical trial that therapeutic interventions targeting the OC methylome reverse drug resistance and induce meaningful clinical responses. We showed that repetitive low-dose decitabine reactivated silenced genes and restored sensitivity to carboplatin, providing strong clinical and biological support for further study of hypomethylating agents in heavily pre-treated, platinum-resistant ovarian cancer patients. While the FDA-approved demethylating agent decitabine is prone to deamination by cytidine deaminase, SGI-110 (Astex Pharmaceuticals, Inc.), a dinucleotide analogue of decitabine, is more stable, less toxic, and a promising alternative to restoring silenced TSG expression in cancer cells by reversal of DNA methylation. Our preclinical evaluation demonstrated that SGI-110 resensitized platinum-resistant OC cell lines to cisplatin (CDDP) (3-fold reduction in IC50) and reduced the CDDP IC50. SGI-110 treatment induced significant demethylation and subsequent transcriptional derepression of tumor suppressors and differentiation-associated genes in OC cells. SGI-110 alone or in combination with CDDP was well tolerated in non-tumor bearing mice. Significant antitumor activity was observed in mice harboring subcutaneous OC tumors and treated with single SGI-110 and SGI-110 + CDDP treatment in both a biweekly and daily (QD5) regimen. In addition to reducing tumor growth in xenografts, SGI therapy was effective in causing global as well as TSG demethylation and gene reexpression in vivo. Furthermore, the antitumor activity of SGI-110 was associated with reduced chromatin compaction, allowing greater CDDP intercalation into DNA, as assessed by increased DNA platinum adducts in SGI-treated OC cells. The results of our preclinical study support our recently activated clinical trial NCT01696032 using SGI-110 in combination with carboplatin in patients with recurrent, platinum-resistant OC. Clinical specimens (tumor and plasma samples) will be analyzed for epigenetic biomarker changes. We seek to bring forward the new concept of epigenetic targeting in platinum resistant OC by priming the tumors with SGI-110 and set the stage for interventions targeting the OC epigenome, as well as guide and impact the design of future clinical investigations in OC. Citation Format: Kenneth P. Nephew, Daniela Matei, Pietro Taverna, Fang Fang, Jessica Tang, Gavin Choy, John Lyons, Mohammad Azab, Jay Pilrose, John Turchi. Targeting the methylome for epigenetic resensitization of ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA17.

Background: Amuvatinib is an oral multi-targeted TKI of c-Kit and PDGFRα and modulates DNA repair by down regulation of Rad51. Rad51 is a key protein in the homologous recombination repair pathway for DNA double strand breaks which can mediate resistance to DNA-damaging agents. Amuvatinib has demonstrated synergistic activity preclinically with DNA damaging chemotherapy agents including etoposide and doxorubicin. Amuvatinib in combination with DNA damaging agents resulted in clinical responses in SCLC patients, induced Rad51 suppression, and increased DNA damage (53BP1 foci) in skin punch biopsies. These results provided the justification for a Phase 2, OL study of amuvatinib in combination with platinum and etoposide (PE) chemotherapy in SCLC patients who have not responded to or relapsed after standard treatment (ESCAPE; TrEatment of Small Cell lung cancer with Amuvatinib in combination with Platinum Etoposide). Methods: Patients ≥ 18 years, ECOG PS 0-2, with confirmed SCLC who met one of the following major eligibility criteria were enrolled based on prior PE response: 1) disease progression during PE, 2) relapse ≤ 90 days, 3) SD as best response after at least 2 cycles. Patients who received second-line therapy were eligible if they met any one of these 3 conditions and all other study eligibility criteria. An optimal Simon 2-stage design was employed (α=10%, β=10%, p0=10%, p1=25%). In Stage 1, 21 patients were to be enrolled and ≥ 3 confirmed responses (CR or PR) were required in order to proceed to Stage 2, where an additional 29 patients were to be enrolled. Amuvatinib was administered PO 300 mg TID. Results: Twenty-three patients, median age of 62 years (range, 44-80); 11 M/12 F; ECOG PS 0 (n=3), 1 (n=12), 2 (n=6), were enrolled in Stage 1 and received a median of two 21-day cycles (range, 1-10). At study entry, 9 (39%), 11 (48%), and 3 (13%) patients presented with disease progression, relapse ≤ 90 days, and SD after at least 2 cycles of PE, respectively. Per PI's assessment, 4 PRs and 7 SDs were observed as best response. Per RECIST 1.1, 2 PRs and 3 SDs were confirmed by follow-up scan ≥ 4 weeks apart for an overall clinical benefit rate (CBR) of 5/23 (22%). No CRs were observed. Grade 3/4 suspected amuvatinib related AEs were neutropenia, thrombocytopenia, atrial fibrillation, diarrhea, esophagitis, and hypercalcemia (1 patient each; 4%); hypokalemia and leukopenia, (2 patients each; 9%). By IHC, baseline expression of RAD51, ERCC1, Chk2, ATM, cKit, and RB will be evaluated and correlated with response. Conclusions: Amuvatinib demonstrated an overall CBR of 22% in refractory SCLC. While clinical activity was observed, the response rate in Stage 1 did not meet pre-specified study primary endpoint. The safety profile of amuvatinib is consistent with previous published reports of manageable toxicity with non-overlapping toxicities with PE chemotherapy. Citation Format: Lauren Byers, Leora Horn, Jitendra Gandhi, Goetz Kloecker, Taofeek K. Owonikoko, Saiama Waqar, Maciej J. Krzakowski, Gavin Choy, Nancy Cecchettini, Pietro Taverna, Amarpal Sahai, Mojtaba Noursalehi, Mohammad Azab, D. Ross Camidge. A phase 2 study of Amuvatinib (MP-470), the first RAD51 inhibitor in combination with platinum-etoposide (PE) in refractory or relapsed small cell lung cancer (ESCAPE). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2095. doi:10.1158/1538-7445.AM2013-2095

Background: Ovarian cancer (OC) progression is associated with accumulation of epigenetic changes leading to transcriptional silencing of tumor suppressor and chemo-responsiveness associated genes. We recently demonstrated for the first time in a clinical trial that therapeutic interventions targeting the OC methylome reverse drug resistance and induce meaningful clinical responses. While the FDA-approved demethylating agent decitabine is prone to deamination by cytidine deaminase, SGI-110 (Astex Pharmaceuticals, Inc.), a dinucleotide analogue of decitabine, is more stable, less toxic, and a promising alternative to restoring silenced TSG expression in cancer cells by reversal of DNA methylation. Our previous preclinical evaluation demonstrated that SGI-110 resensitized platinum-resistant OC cell lines to cisplatin (CDDP) (3-fold reduction in IC50) and reduced the CDDP IC50 by >2-fold in the A2780 platinum sensitive OC cell line. SGI-110 treatment induced significant demethylation and subsequent transcriptional derepression of tumor suppressors and differentiation-associated genes in A2780 ovarian cancer cells. In addition, non-tumor bearing mice tolerated SGI-110 alone or in combination with CDDP. Methods: In the current study, we assessed the activity of SGI-110 in combination with CDDP to retard the growth of platinum sensitive or drug resistant human ovarian cancer xenografts. Mice were injected with SGI-110 (2 mg/kg or 5 mg/kg, SQ.) or CDDP (2 mg/kg or 4 mg/kg, IP.) treatment or in combination in a biweekly or QD5 regimen. Results: Significant antitumor activity was observed in the single SGI-110 and SGI-110 + CDDP treatment in both the biweekly and QD5 regimen mice bearing a subcutaneous A2780 OC xenograft. The effect of SGI-110 treatment alone was greater than CDDP treatment alone. Pyrosequencing analysis was use to reaffirm global demethylation by SGI-110 treatment, based on significant demethylation of LINE1 in peripheral blood mononuclear cells. As expected, SGI-110 treatment resulted in derepression of TSGs (MLH1 and RASSF1A), HOXA10 and HOXA11 (differentiation-associated genes), CSNK1D (DNA repair), IL2RG (receptor subunit in Jak/STAT pathway), and STAT5B (transcription factor) in tumors (as observed in the in vitro study). To test the hypothesis that SGI-110 treatment influenced DNA adduct formation and repair of cisplatin-DNA damage, we are currently analyzing the amount of platinum-DNA damage induced by CDDP treatment using mass spectrometry. Conclusions: The results of our preclinical study support our recently activated clinical trial using SGI-110 in combination with carboplatin in patients with recurrent, platinum-resistant OC. Citation Format: Jessica Tang, Fang Fang, Yinu Wang, Pietro Taverna, David F.B. Miller, Gavin Choy, Mohammad Azab, Daniela Matei, Katherine S. Pawelczak, Pamela VanderVere-Carozza, Michael Wagner, John J. Turchi, Kenneth P. Nephew. The novel, small molecule DNA methylation inhibitor SGI-110 as an ovarian cancer chemosensitizer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4623. doi:10.1158/1538-7445.AM2013-4623

Abstract 414 Background: SGI-110 is a dinucleotide of decitabine (DAC) and deoxyguanosine formulated as a low volume and pharmaceutically stable SQ injection allowing more extended decitabine exposure than DAC IV infusion. The anticipated differentiated PK profile offers the potential of improved biological and clinical activity and safety over currently available HMAs. Methods: A randomized Phase 1–2 FIH Pharmacokinetics/Pharmacodynamics (PK/PD)-guided, dose-escalation study has been conducted in patients with relapsed/refractory intermediate or high-risk MDS or AML. The objective of the first stage (dose escalation) is to determine safety and tolerability and to establish the Maximum Tolerated Dose (MTD) and Biologically Effective Dose (BED). Patients were randomized to one of two SQ regimens (dailyx5 or once weeklyx3, 28-day courses). PD is evaluated by LINE-1 global DNA hypomethylation. The second stage (dose expansion) is to determine the clinical activity and safety in AML and MDS using the established BED and MTD. We report here the results of the dose escalation phase which has completed enrolment. Results: 78 patients (64 AML, 14 MDS) were enrolled in the dose escalation phase: 44 patients in the dailyx5 regimen and 34 in the weeklyx3 regimen. Median age was 69 years (range 29–86), 65% were male, and 82% had ECOG PS of 0–1. Median number of prior regimens was 3 (range 1–9), 59% of patients had prior HMA treatment (50% of AML patients, and 100% of MDS patients). Six patients are still ongoing treatment. The PK profile demonstrated efficient conversion of SGI-110 to decitabine as predicted from the SGI-110 rational design, resulting in longer decitabine exposure window (beyond 8 hrs) compared to DAC IV (3–4 hrs). At SGI-110 dose range of 60–125 mg/m2, observed mean decitabine AUCs (88–231 ng*hr/mL) reach or exceed the therapeutic range seen with 20 mg/m2 DAC IV (115 ng*hr/mL) while achieving only a small fraction of the Cmax (26–64 ng/mL vs 146 ng/mL for DAC IV). The effective half-life for decitabine after SQ SGI-110 injection appeared to be prolonged (up to 4-fold or ∼2.4 hrs) compared to DAC IV (0.58 hrs). Decitabine exposures (AUC) increased in a dose-proportional manner regardless of the regimen and no accumulation was observed. Dose-related LINE-1 hypomethylation was observed in patients treated with the daily regimen between 18 and 60 mg/m2; a plateau in maximum average hypomethylation (∼25%) was evident at higher daily doses (90-125 mg/m2) and therefore the BED for the dailyx5 schedule is established at 60 mg/m2. The 25% average hypomethylation of LINE-1 compares favorably with that observed historically after DAC IV at the dose of 20 mg/m2 dailyx5. The extent of LINE-1 hypomethylation after weeklyx3 SGI-110 was inferior as the maximum average hypomethylation plateaued at ∼8% from baseline. Starting at 36 mg/m2 daily and 60 mg/m2 weekly (44 AML, and 7 MDS patients), clinical responses were observed: 2CRs, 1CRp, and 1CRi in heavily pretreated AML patients; 1 mCR and 1 HI in MDS patients previously treated with azacitidine. All responses were in patients who achieved >10% LINE-1 hypomethylation. The most common Adverse Events (AEs), regardless of relationship to SGI-110, were diarrhea (21%), febrile neutropenia (17%), fatigue/injection site pain/nausea at 15% each. The most common drug-related AEs were injection site pain (15%), fatigue (8%), nausea (6%), and thrombocytopenia (5%). MTD was not reached with the weekly regimen up to 125 mg/m2 weeklyx3. With the daily regimen, 125 mg/m2dailyx5 resulted in 2 Dose-Limiting Toxicities (DLTs) of febrile neutropenia in 3 MDS patients (1 associated with bacteremia, and the other with sepsis and thrombocytopenia Grade 4) while none of the 9 patients with AML had DLT at that dose. Conclusions: SGI-110 is well tolerated at doses higher than BED which is established at 60 mg/m2 dailyx5 where average hypomethylation of ∼25% was achieved. MTD estimated to be 90 mg/m2 dailyx5 for MDS and 125 mg/m2dailyx5 for AML patients. SQ administration of SGI-110 achieved efficient conversion to decitabine resulting in an improved PK profile over DAC IV. Clinical responses were observed in this heavily pretreated population and they seem to correlate with the extent of LINE-1 hypomethylation. Study is currently enrolling patients in the dose-expansion Phase 2 stage. Disclosures: Kantarjian: Astex Pharmaceuticals: Research Funding. Roboz:Astex Pharmaceuticals: Research Funding. Rizzieri:Astex Pharmaceuticals: Research Funding. Stock:Astex Pharmaceuticals: Research Funding. O'Connell:Astex Pharmaceuticals: Research Funding. Griffiths:Astex Pharmaceuticals: Research Funding. Yee:Astex Pharmaceuticals: Research Funding. Tibes:Astex Pharmaceuticals: Research Funding. Garcia-Manero:Astex Pharmaceuticals: Research Funding. Ravandi:Astex Pharmaceuticals: Research Funding. Walsh:Astex Pharmaceuticals: Research Funding. Feldman:Astex Pharmaceuticals: Research Funding. Ritchie:Astex Pharmaceuticals: Research Funding. Rao:Astex Pharmaceuticals: Research Funding. Decastro:Astex Pharmaceuticals: Research Funding. Schimmer:Astex Pharmaceuticals: Research Funding. Mesa:Astex Pharmaceuticals: Research Funding. Syed:Astex Pharmaceuticals: Research Funding. Choy:Astex Pharmaceuticals: Employment. Oganesian:Astex Pharmaceuticals: Employment. Taverna:Astex Pharmaceuticals: Employment. Azab:Astex Pharmaceuticals: Employment. Chung:Astex Pharmaceuticals: Research Funding. Issa:Astex Pharmaceuticals: Honoraria, Research Funding.

Deoxycytosine methylation of CpG islands in promoter regions of tumor suppressor genes (TSGs) plays a prominent role in the development and progression of drug-resistant epithelial ovarian cancer (OC). We previously demonstrated in a phase I/II trial that the DNA methylation inhibitor decitabine alters DNA methylation and restores platinum sensitivity in platinum-resistant OC patients, resulting in significant clinical activity. SGI-110 (Astex Pharmaceuticals) is a DNA hypomethylating agent with demonstrated activity in restoring silenced TSG expression in cancer cells by reversal of DNA methylation. As a decitabine-deoxyguanosine dinucleotide, SGI-110 has been shown to be less prone to deamination by cytidine deaminase and could have advantages over decitabine, such as better stability, less toxicity and a more convenient and less frequent SQ administration. We examined SGI-110 for its ability to inhibit OC cell proliferation and to demethylate and induce TSGs in vitro and in vivo. A 48 hour pretreatment with SGI-110 resensitized drug-resistant ovarian cancer cell lines to cisplatin (3-fold reduction in IC50 of cisplatin). In A2780 platinum sensitive OC cells, SGI-110 pre-treatment for 5 days reduced cisplatin IC50 by >2-fold. Prolonged (7 days) SGI-110 treatment reduced by 2-fold the number of ALDH1+ cells in SKOV3 and A2780 cells, suggesting an effect on the stem cell population, potentially involved in drug resistance. SGI-110 induced significant demethylation of TSGs ras-associated domain family 1A (RASSF1A) and human MutL homologue-1 (MLH1) and the differentiation-associated gene HOXA10; furthermore, RASSF1A, MLH1 and HOXA10 gene reexpression was also observed after 48 hour SGI-110 treatment. SGI-110 prevented TGF-β induced epithelial to mesenchymal transition of OC cells, as measured morphologically and by quantification of E-cadherin, Zeb1, Slug and miR200c expression levels. SGI-110 suppressed E-cadherin promoter methylation induced by TGF-β. We then examined the in vivo tolerability and efficacy of SGI-110, singly and in combination with cisplatin, in nude athymic mice. Mice were injected qd or bi-weekly with SGI-110 (sc) and/or cisplatin (ip) and body weights were measured twice weekly. In the qd regimen, SGI-110 2 mg/kg plus 4 mg/kg cisplatin was tolerated. The 10 mg/kg bi-weekly dose of SGI-110 was tolerated, either alone or in combination with 2 mg/kg cisplatin (5mg/kg SGI-110 plus 4 mg/kg cisplatin was similarly tolerated). SGI-110 induced significant global hypomethylation, as determined by pyrosequencing analysis of LINE1 demethylation in peripheral blood mononuclear cells. We are currently assessing the activity of SGI-110 in combination with cisplatin to retard the growth of platinum resistant human ovarian cancer xenografts. In summary, SGI-110 combined with platinum is a promising clinical combination for the therapy of ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4077. doi:1538-7445.AM2012-4077

3074 Background: Amuvatinib is an oral multi-targeted TKI which inhibits the mutant forms of c-kit, and PDGFRα. It also disrupts DNA repair probably through suppression of Homologous Recombination ...

e13511 Background: MP-470 (MP) is an oral multi-targeted tyrosine kinase inhibitor which inhibits a number of validated tumor targets including c-kit, flt3, and PDGFα. MP470 targets cancer cells by disrupting DNA repair, an important survival pathway in many human cancers. Results presented herein are from two arms of a phase-Ib five arm trial of MP combined with standard of care (SOC) anti- cancer therapies. Methods: MP is administered in combination with SOC in a 21-day cycle. Adults with ECOG PS of 0–2 and malignant disease appropriate for SOC regimens consisting of paclitaxel/carboplatin (PC), carboplatin/etoposide (CE), topotecan, docetaxel, and erlotinib were enrolled. Each arm follows a 3+3 design where MP is escalated based on the modified Fibonacci sequence until the MTD of MP in combination with SOC agents is reached. RECIST and CTCAE are utilized to assess response and safety, respectively. The primary objectives of the study are to determine the MTD, DLTs, and quantify the effects of MP on the PK of SOC agents. Results: Between Dec 2007 and Aug 2008, 26 subjects were enrolled in the PC and CE arms and received a total of 70 cycles (median 2; range, 0–8) of MP at 4 dose levels (100–500 mg/day). Median number of prior therapies was 2 (range, 0–19). Male/Female: 14/12. Median age, 56 years (range, 24–76). Subjects completing ≥ 6 and ≥ 4 cycles were 5 and 7, respectively. Six PRs (2 neuroendocrine, 2 SCLC, 1 NSCLC, 1 small cell of anal canal) and 3 SDs (≥ 4 cycles) was observed. The MTDs have not been reached and DLTs have not been identified. Adverse events occurring in ≥ 15% of patients were myelosuppression, diarrhea, constipation, nausea, reflux, fatigue, alopecia, rash, neuropathy, anorexia, hypokalemia, dyspnea, and myalgias. MP470 did not alter the kinetics of SOC agents. Dose escalation in the PC and CE arms is ongoing. Conclusions: MP470 combined with carboplatin-containing regimens may promote tumor regression and may also sensitize/resensitize tumors to the anticancer effects of such agents. An amendment will be issued to collect tumor tissue biopsy at baseline and during treatment to adequately evaluate DNA damage in tumor tissue. [Table: see text]