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Phase I trial of oral 5-fluoro-2′-deoxycytidine with oral tetrahydrouridine in patients with advanced solid tumors
S90
Poster abstracts
Poster Session – Epigenetic modulators, Wednesday 29 November 2016
Conclusions: In summary, ODM-207 is a new generation BET inhibitor for treatment of advanced cancers. It has activity in prostate cancer models that have developed resistance to second generation anti-androgens. ¨ Conflict of interest: Other Substantive Relationships: Bjorkman M, Mattila E, Riikonen R, Ikonen T, Nicorici D, Kallio P and Moilanen A are employed by Orion Corporation Orion Pharma. Sekhar C, Mahaboobi J, Marappan S, Samajdar S and Ramachandra M are employed by Aurigene Discovery Technologies Limited. 269 Poster (Board P095) Phase I trial of oral 5-fluoro-2 -deoxycytidine with oral tetrahydrouridine in patients with advanced solid tumors G. O’Sullivan Coyne1 , A.P. Chen1 , S. Kummar1 , R.S. Meehan1 , J. Collins1 , J. Zlott1 , K. Kelly2 , H.J. Lenz3 , E.M. Newman4 , R. Morgan4 , L. Juwara5 , J. Eiseman6 , J.H. Beumer6 , J. Tomaszewski1 , J. Doroshow1 . 1 National Cancer Institute, Division of Cancer Treatment and Diagnosis, Bethesda, USA; 2 Comprehensive Cancer Center, UC Davis, Sacramento, USA; 3 USC, Norris Comprehensive Cancer Center, Los Angeles, USA; 4 City of Hope, National Medical Center, Duarte, USA; 5 Frederick National Laboratory, DCTD, Frederick, USA; 6 UPMC, University of Pittsburg Cancer Instittue, Pennsylvania, USA Background: Epigenetic methylation-mediated gene silencing has been implicated in neoplastic transformation. 5-Fluoro-2 -deoxycytidine (FdCyd), a fluoropyrimidine nucleoside analog, has a short (10-minute) half-life and is rapidly degraded in vivo by cytidine deaminase. Co-administration of tetrahydrouridine (THU), an inhibitor of cytidine/deoxycytidine deaminase, has been shown to increase the AUC of FdCyd more than 4-fold. Increased FdCyd exposure allows it to be taken up intracellularly, and to be incorporated into DNA, inhibiting the action of the enzyme DNA methyltransferase (DNMT). The consequent decrease in DNA methylation can result in the re-expression of tumor suppressor genes. Intravenous (IV) FdCyd+THU has been evaluated in a Phase I clinical trial with preliminary evidence of activity. The current trial investigates the oral (PO) administration of both agents, because the intravenous administration schedule was cumbersome. Following achievement of an FdCyd Cmax of 1 mM in one patient (pt), consideration was given to increasing the number of days and frequency of FdCyd + THU administration, as this is the level attained following IV administration sufficient to re-express silenced genes in vivo. Materials and Methods: This is a multicenter 3+3 trial, with NCI as the coordinating center. FdCyd+THU were administered 3−7days q wk ×2 in 21-day cycles, with THU given PO 30 minutes prior to FdCyd. Main aims of this study were to determine the PK profile of PO FdCyd, the effect of study treatment on re-expression of select genes silenced by methylation in circulating tumor cells (CTCs), and to document the clinical benefit rate (CR+PR+SD at 4 months) in pts treated with the study drug combination at the maximally tolerated dose (MTD). Eligibility criteria: solid tumor pts whose disease has progressed on standard therapy, ECOG 2, and normal organ function. Results: A total of 40 pts have been accrued to date on trial. PK data showed the target Cmax for FdCyd was achieved at dose level (DL) 4; following enrollment to DL5, we increased the number of days of administration of FdCyd+THU (DL6−9) and the frequency of administration (DL10−11). DLTs were seen at the BID DLs (10−11). The MTD was determined to be DL8: FdCyd+THU (mg) 160 mg+3000 respectively, 1× daily days 1−6 and 8−13. Noted grade 4 toxicities were thrombocytopenia (1 pt), neutropenia (3) and lymphopenia (3). Most common grade 3 toxicity was lymphopenia (12), with other grade 3 toxicities occurring in less than 5 patients (anemia, diarrhea, nausea and fatigue). 19 pts had stable disease, with a median of 12 cycles of treatment (range 1−17). Conclusions: This trial has shown the feasibility of administrating FdCyd orally with good drug exposure. Evaluation of disease activity will continue at the MTD. The analysis of gene re-expression in CTCs is ongoing. No conflict of interest. 270 Poster (Board P096) A ChIP-Seq spike-in method enables detection of global histone modification changes across the genome S. Chlamydas1 , B. Egan1 , M. Craske1 , P. Labhart1 , C. Henry1 , T. Kelly1 , G. Guler2 , C.-C. Yuan3 , P. Trojer3 , M. Classon2 . 1 1 Active Motif Inc., Carlsbad, CA, USA; 2 Genentech Inc., South San Francisco, CA, USA; 3 Constellation Pharmaceuticals, Cambridge, MA, USA Small molecule inhibitors of EZH2 have great therapeutic potential for cancer. In order to fully understand how inhibitors of EZH2 function therapeutically, it is necessary to understand how inhibitor treatment
alters H3K27me3 occupancy across the entire genome and how this may affect gene expression. Genome-wide maps of histone modification patterns can be generated using ChIP-Seq, however our experience has shown that current ChIP-Seq methodology and available ChIPSeq data analysis approaches do not detect the expected genomewide decrease in H3K27me3 following EZH2 inhibitor treatment. To overcome this challenge we developed a novel chromatin spike-in strategy for ChIP-Seq. Specifically, we introduced drosophila chromatin as a minor fraction of total chromatin into our ChIP reactions and added a drosophila specific antibody as a way to consistently pull out drosophila chromatin as a minor fraction of the total ChIP DNA. The drosophila ChIP-Seq reads are used to normalize the human ChIP-Seq data from DMSO and inhibitor treated samples. Using this strategy we now detect dramatic reductions in H3K27me3 levels in the presence of EZH2 inhibitors. Small molecule inhibitors of EZH2 have great therapeutic potential for cancer. In order to fully understand how inhibitors of EZH2 function therapeutically, it is necessary to understand how inhibitor treatment alters H3K27me3 occupancy across the entire genome and how this may affect gene expression. Genome-wide maps of histone modification patterns can be generated using ChIP-Seq technology. In order to normalize the biological variation across samples but also for technical variation that can occur during the ChIP procedure we introduce the Spike-In method in genome wide studies. No conflict of interest. 272 Poster (Board P098) Global disruption of productive transcriptional elongation via targeted BET protein degradation G. Winter1 , D. Buckley2 , A. Mayer3 , J. Roderick4 , M. Kelliher4 , S. Churchman3 , J. Bradner5 . 1 CeMM, Research Center for Molecular Medicine, Chemical Biology of Oncogenic Gene Regulation, Wien, Austria; 2 Dana Farber Cancer Institute, Medical Oncology, Boston, USA; 3 Harvard Medical School, Genetics, Boston, USA; 4 UMASS Medical School, UMASS Medical School, Worcester, USA; 5 NIBR-Novartis Institute for Biomedical Research, NIBR − Novartis Institute for Biomedical Research, Cambridge, USA Background: Aberrant gene regulatory processes govern and sustain virtually all aspects and features of human malignancies. Thus, targeting cancer by exploiting non-oncogene addictions to the core transcriptional machinery represents an intriguing therapeutic strategy. However, disruption of oncogenic transcription and cell specification has historically been challenging as transcription factors as well as transcriptional co-activators often lack enzymatically active domains that can be blocked by competitive small molecule inhibitors. To overcome this limitation, we recently devised a strategy for ligand-induced target protein degradation using bifunctional small molecules capable of recruiting the E3 ligase cereblon (CRBN). Focusing our initial efforts on degraders of the BET family of proteins, we observed that they exhibit superior efficacy than competitive BET bromodomain inhibitors through unknown mechanisms. Materials and Methods: In order to mechanistically explain the differential molecular pharmacology, we used optimized small-molecule degraders and spike-in normalized, kinetic measurements of chromatin structure and state as well as transcriptional output. Results: We identified a hypersensitivity of T-cell acute lymphoblastic leukemia (T-ALL) cell lines, PDX- and animal models to targeted BET degradation. Mechanistically, we identified that acute loss of BET proteins via targeted degradation leads to a global disruption of transcriptional elongation that features a disproportional impact on a densely interconnected, auto-regulatory network of transcription factors central to T-ALL pathogenesis. Conclusions: Targeted BET degradation enabled us to identify an unrecognized, essential role for BRD4 in global control of transcriptional pause-release and to exploit transcriptional addictions in T-ALL that were intractable using competitive BET bromodomain inhibitors. Conflict of interest: Other Substantive Relationships: GW is a consultant for C4 Therapeutics; JB is an employee of Novartis Institutes of BioMedical Research as of January 2016; JEB is a Scientific Founder of SHAPE Pharmaceuticals, Syros Pharmaceuticals, Acetylon Pharmaceuticals, Tensha Therapeutics and C4 Therapeutics and is the inventor on IP licensed to these entities.
Poster abstracts
Poster Session – Epigenetic modulators, Wednesday 29 November 2016
Conclusions: In summary, ODM-207 is a new generation BET inhibitor for treatment of advanced cancers. It has activity in prostate cancer models that have developed resistance to second generation anti-androgens. ¨ Conflict of interest: Other Substantive Relationships: Bjorkman M, Mattila E, Riikonen R, Ikonen T, Nicorici D, Kallio P and Moilanen A are employed by Orion Corporation Orion Pharma. Sekhar C, Mahaboobi J, Marappan S, Samajdar S and Ramachandra M are employed by Aurigene Discovery Technologies Limited. 269 Poster (Board P095) Phase I trial of oral 5-fluoro-2 -deoxycytidine with oral tetrahydrouridine in patients with advanced solid tumors G. O’Sullivan Coyne1 , A.P. Chen1 , S. Kummar1 , R.S. Meehan1 , J. Collins1 , J. Zlott1 , K. Kelly2 , H.J. Lenz3 , E.M. Newman4 , R. Morgan4 , L. Juwara5 , J. Eiseman6 , J.H. Beumer6 , J. Tomaszewski1 , J. Doroshow1 . 1 National Cancer Institute, Division of Cancer Treatment and Diagnosis, Bethesda, USA; 2 Comprehensive Cancer Center, UC Davis, Sacramento, USA; 3 USC, Norris Comprehensive Cancer Center, Los Angeles, USA; 4 City of Hope, National Medical Center, Duarte, USA; 5 Frederick National Laboratory, DCTD, Frederick, USA; 6 UPMC, University of Pittsburg Cancer Instittue, Pennsylvania, USA Background: Epigenetic methylation-mediated gene silencing has been implicated in neoplastic transformation. 5-Fluoro-2 -deoxycytidine (FdCyd), a fluoropyrimidine nucleoside analog, has a short (10-minute) half-life and is rapidly degraded in vivo by cytidine deaminase. Co-administration of tetrahydrouridine (THU), an inhibitor of cytidine/deoxycytidine deaminase, has been shown to increase the AUC of FdCyd more than 4-fold. Increased FdCyd exposure allows it to be taken up intracellularly, and to be incorporated into DNA, inhibiting the action of the enzyme DNA methyltransferase (DNMT). The consequent decrease in DNA methylation can result in the re-expression of tumor suppressor genes. Intravenous (IV) FdCyd+THU has been evaluated in a Phase I clinical trial with preliminary evidence of activity. The current trial investigates the oral (PO) administration of both agents, because the intravenous administration schedule was cumbersome. Following achievement of an FdCyd Cmax of 1 mM in one patient (pt), consideration was given to increasing the number of days and frequency of FdCyd + THU administration, as this is the level attained following IV administration sufficient to re-express silenced genes in vivo. Materials and Methods: This is a multicenter 3+3 trial, with NCI as the coordinating center. FdCyd+THU were administered 3−7days q wk ×2 in 21-day cycles, with THU given PO 30 minutes prior to FdCyd. Main aims of this study were to determine the PK profile of PO FdCyd, the effect of study treatment on re-expression of select genes silenced by methylation in circulating tumor cells (CTCs), and to document the clinical benefit rate (CR+PR+SD at 4 months) in pts treated with the study drug combination at the maximally tolerated dose (MTD). Eligibility criteria: solid tumor pts whose disease has progressed on standard therapy, ECOG 2, and normal organ function. Results: A total of 40 pts have been accrued to date on trial. PK data showed the target Cmax for FdCyd was achieved at dose level (DL) 4; following enrollment to DL5, we increased the number of days of administration of FdCyd+THU (DL6−9) and the frequency of administration (DL10−11). DLTs were seen at the BID DLs (10−11). The MTD was determined to be DL8: FdCyd+THU (mg) 160 mg+3000 respectively, 1× daily days 1−6 and 8−13. Noted grade 4 toxicities were thrombocytopenia (1 pt), neutropenia (3) and lymphopenia (3). Most common grade 3 toxicity was lymphopenia (12), with other grade 3 toxicities occurring in less than 5 patients (anemia, diarrhea, nausea and fatigue). 19 pts had stable disease, with a median of 12 cycles of treatment (range 1−17). Conclusions: This trial has shown the feasibility of administrating FdCyd orally with good drug exposure. Evaluation of disease activity will continue at the MTD. The analysis of gene re-expression in CTCs is ongoing. No conflict of interest. 270 Poster (Board P096) A ChIP-Seq spike-in method enables detection of global histone modification changes across the genome S. Chlamydas1 , B. Egan1 , M. Craske1 , P. Labhart1 , C. Henry1 , T. Kelly1 , G. Guler2 , C.-C. Yuan3 , P. Trojer3 , M. Classon2 . 1 1 Active Motif Inc., Carlsbad, CA, USA; 2 Genentech Inc., South San Francisco, CA, USA; 3 Constellation Pharmaceuticals, Cambridge, MA, USA Small molecule inhibitors of EZH2 have great therapeutic potential for cancer. In order to fully understand how inhibitors of EZH2 function therapeutically, it is necessary to understand how inhibitor treatment
alters H3K27me3 occupancy across the entire genome and how this may affect gene expression. Genome-wide maps of histone modification patterns can be generated using ChIP-Seq, however our experience has shown that current ChIP-Seq methodology and available ChIPSeq data analysis approaches do not detect the expected genomewide decrease in H3K27me3 following EZH2 inhibitor treatment. To overcome this challenge we developed a novel chromatin spike-in strategy for ChIP-Seq. Specifically, we introduced drosophila chromatin as a minor fraction of total chromatin into our ChIP reactions and added a drosophila specific antibody as a way to consistently pull out drosophila chromatin as a minor fraction of the total ChIP DNA. The drosophila ChIP-Seq reads are used to normalize the human ChIP-Seq data from DMSO and inhibitor treated samples. Using this strategy we now detect dramatic reductions in H3K27me3 levels in the presence of EZH2 inhibitors. Small molecule inhibitors of EZH2 have great therapeutic potential for cancer. In order to fully understand how inhibitors of EZH2 function therapeutically, it is necessary to understand how inhibitor treatment alters H3K27me3 occupancy across the entire genome and how this may affect gene expression. Genome-wide maps of histone modification patterns can be generated using ChIP-Seq technology. In order to normalize the biological variation across samples but also for technical variation that can occur during the ChIP procedure we introduce the Spike-In method in genome wide studies. No conflict of interest. 272 Poster (Board P098) Global disruption of productive transcriptional elongation via targeted BET protein degradation G. Winter1 , D. Buckley2 , A. Mayer3 , J. Roderick4 , M. Kelliher4 , S. Churchman3 , J. Bradner5 . 1 CeMM, Research Center for Molecular Medicine, Chemical Biology of Oncogenic Gene Regulation, Wien, Austria; 2 Dana Farber Cancer Institute, Medical Oncology, Boston, USA; 3 Harvard Medical School, Genetics, Boston, USA; 4 UMASS Medical School, UMASS Medical School, Worcester, USA; 5 NIBR-Novartis Institute for Biomedical Research, NIBR − Novartis Institute for Biomedical Research, Cambridge, USA Background: Aberrant gene regulatory processes govern and sustain virtually all aspects and features of human malignancies. Thus, targeting cancer by exploiting non-oncogene addictions to the core transcriptional machinery represents an intriguing therapeutic strategy. However, disruption of oncogenic transcription and cell specification has historically been challenging as transcription factors as well as transcriptional co-activators often lack enzymatically active domains that can be blocked by competitive small molecule inhibitors. To overcome this limitation, we recently devised a strategy for ligand-induced target protein degradation using bifunctional small molecules capable of recruiting the E3 ligase cereblon (CRBN). Focusing our initial efforts on degraders of the BET family of proteins, we observed that they exhibit superior efficacy than competitive BET bromodomain inhibitors through unknown mechanisms. Materials and Methods: In order to mechanistically explain the differential molecular pharmacology, we used optimized small-molecule degraders and spike-in normalized, kinetic measurements of chromatin structure and state as well as transcriptional output. Results: We identified a hypersensitivity of T-cell acute lymphoblastic leukemia (T-ALL) cell lines, PDX- and animal models to targeted BET degradation. Mechanistically, we identified that acute loss of BET proteins via targeted degradation leads to a global disruption of transcriptional elongation that features a disproportional impact on a densely interconnected, auto-regulatory network of transcription factors central to T-ALL pathogenesis. Conclusions: Targeted BET degradation enabled us to identify an unrecognized, essential role for BRD4 in global control of transcriptional pause-release and to exploit transcriptional addictions in T-ALL that were intractable using competitive BET bromodomain inhibitors. Conflict of interest: Other Substantive Relationships: GW is a consultant for C4 Therapeutics; JB is an employee of Novartis Institutes of BioMedical Research as of January 2016; JEB is a Scientific Founder of SHAPE Pharmaceuticals, Syros Pharmaceuticals, Acetylon Pharmaceuticals, Tensha Therapeutics and C4 Therapeutics and is the inventor on IP licensed to these entities.