Abstract only
TPS2623
Background: PAZ is a multi-targeted tyrosine kinase inhibitor of VEGFR, PDGFR, and C-KIT, approved for metastatic RCC and refractory sarcoma based on phase III data showing ...prolonged PFS (JCO 2010;28:1061-8 and Lancet 2012;379:1879-86). PCI is a potent pan-HDAC inhibitor (pan-HDACi), observed in cell lines to change regulation of genes involved in cell signaling, apoptosis, proliferation, differentiation, and angiogenesis (Anticancer Res 2011;31:1115-23). Pre-clinical models suggest epigenetic modification with an HDACi potentiates PAZ’s efficacy by causing chromatin instability and gene expression changes involved in drug resistance (Can Res 2005;65:3815-22 and BJC 2009;100:758-63). We therefore designed a Phase Ia/b clinical trial combining PCI with PAZ in pts with advanced solid tumors, with an expansion cohort for preliminary efficacy in RCC and sarcoma. Methods: Primary objective of this phase Ia/b study is to evaluate the safety and tolerability of the combination of PAZ and PCI to determine the MTD and RP2D. In phase Ia, we utilized an accelerated phase I design. The phase Ib portion will include up to 20 pts per expansion cohort, for up to 32-70 pts enrolled. In phase 1a, pts receive run-in PCI alone on C1D-7 to D-4. Starting with C1D1, pts receive oral PCI on D1-5, 8-12, 15-19 BID 4 hrs apart and PAZ daily (D1-28) q28D cycle. CORRELATIVES: Pre- and post-treatment (Tx) H3 & H4 acetylation and HDAC activity in PBMCs. In phase Ib, these will also be studied in tumor biopsies. We will measure expression of VEGF, VEGFR, RAD51, HIF, Ki67; and analyze SNPs through genomic profiling. We will correlate response with pre- and post-Tx tumor thymidine uptake using 18F-fluorothymidine (FLT-PET) PET. Current Status: This is the 1
st
trial exploring the combination of an HDACi with PAZ in RCC and sarcoma, where there is an unmet need for new tolerable therapies. It will study FLT-PET, an imaging correlate that captures tumor proliferation and may have a role as a predictive biomarker. We are currently in phase Ia. Enrollment in the 3
rd
cohort exploring higher doses of PAZ will begin in Feb 2013. Clinical trial information: NCT01543763.
Abstract only
1095
Background: ERB is a non-taxane microtubule inhibitor approved for the treatment (Tx) of taxane (TAX) and anthracycline-treated MBC based on improved OS compared to treatment of ...physician choice. In the adjuvant setting, docetaxel/CTX (TC) was superior to doxorubicin/CTX for DFS and OS. ERB is active in TAX-resistant disease with a low rate of peripheral neuropathy (PN); its primary dose-limiting toxicity (DLT) is bone marrow suppression. We hypothesized that the combination of ERB and CTX would be well tolerated and active in patients with TAX-resistant disease, with potential applicability to the adjuvant setting. Methods: We designed a 3+3 phase Ib study of ERB, administered in 2 escalating doses on day 1 and 8, with CTX 600 mg/m
2
day 1 every 21 days. Eligibility included PN ≤ grade 1. Correlative studies to identify predictors of response and toxicity included whole blood for SNPs, GWAS, circulating tumor cells (CTC), and archived tumor RNA/protein expression analysis. Toxicity assessment included QoL and evaluation of PN. Results: 6 patients (pts) with MBC, median age 50 (47-63), were enrolled. All pts had prior TAX exposure and 4 pts had baseline grade 1 PN. Tumor characteristics included hormone receptor + (5 pts), HER2+ (2 pts), and triple-negative (1 pt). Median number of prior Tx for MBC was 5 (1-8). No DLTs were observed; the RP2D is eribulin 1.4 mg/m2 on D1 and D8 with CTX D1 600mg/m2. Neutropenia was the only G3/G4 non-DLT observed at this dose, requiring GCSF support in cycle1 in 2 of 3 pts. All grade toxicities included neutropenia (50%), thrombocytopenia, fatigue, nausea, PN, rash, mucositis, alopecia (33% each), and elevated liver enzymes (17%). Pts received a median of 5.5 cycles (range 3-13), with 3 pts still on Tx. Responses included 2PRs (33%) and 4 SD (67%). 2 pts stopped study Tx for QoL and continued ERB alone. Only 2 pts met threshold of >5CTC/7.5ml at baseline; these had a mean decrease of 90.5% at the start of cycle 2. Conclusions: ERB and CTX is a well-tolerated regimen with promising activity in MBC, with the primary toxicity being neutropenia requiring growth factor support. A phase II study in MBC is underway. Additional correlative studies are ongoing including molecular analyses of CTC. Clinical trial information: NCT01554371.
Abstract only
3058
Background: Preclinical and clinical data suggest pre-exposure of cancer cells to a histone deacetylase inhibitor (HDACi) potentiates topoisomerase inhibitors. HDACi-induced ...histone acetylation and chromatin modulation facilitates DNA access and target recruitment for topo II inhibitors. In vitro data further suggest effective inhibition of HDAC2 is necessary for enhanced epirubicin-induced apoptosis. Methods: This phase I trial explores the safety, tolerability, and maximum tolerated dose (MTD) of escalating doses of panobinostat given orally on days 1, 3, and 5 followed by epirubicin administered intravenously at 75 mg/m2 on day 5 in 21-day cycles. Histone acetylation and HDAC2 expression are evaluated in pre- and post-treatment peripheral blood mononuclear cells (PBMCs) in all patients and in tumor cells of 16 patients treated at the MTD. Results: 36 patients have enrolled 10M/26F, median age 47 years (22-80) in 5 panobinostat cohorts: 20, 30, 40, 50, 60 mg. Tumor types include melanoma (n=6), breast (n=6), sarcoma (n=16), ovarian (n=2), lung (n=2), and one each of neuroblastoma, pancreatic, testicular, and colon cancer. Prior to enrollment, patients received a median of 3 (0-8) prior chemotherapy regimens and 40% had anthracyclines. Dose-limiting toxicities (DLTs) included 1/3 grade 3 fatigue and 1/3 grade 4 thrombocytopenia at 60 mg of panobinostat, 1/6 patient experienced grade 3 atrial fibrillation at 50 mg, defining 50 mg panobinostat as the MTD. Non-dose–limiting grade 3/4 hematological toxicities include neutropenia (n=19, 53%), febrile neutropenia (n=6, 17%), thrombocytopenia (n=6, 17%), and anemia (n=4, 11%). Of 34 evaluable patients, 5 had partial responses and 14 had stable disease in anthracycline-refractory sarcomas (4) and Her2neu positive breast cancer (2), and small cell lung cancer. Correlative studies demonstrate increased H4 acetylation in PBMCs on day 3 and 5 suggesting sufficient histone deacetylase inhibition. Conclusions: Sequence-specific combination of panobinostat and epirubicin shows early activity without potentiating epirubicin toxicity. Dose expansion in anthracycline-pretreated sarcoma patients is ongoing.
Neutral sphingomyelinases (N-SMases) are major candidates for stress-induced ceramide production. However, there is little information on the physiological regulation and roles of the cloned N-SMase ...enzyme, nSMase2. In this study, nSMase2 was found to translocate acutely to the plasma membrane of A549 epithelial cells in response to tumor necrosis factor α (TNF-α) in a time- and dose-dependent manner. Additionally, TNF-α increased N-SMase activity rapidly and transiently both endogenously and in cells overexpressing nSMase2. Furthermore, the translocation of nSMase2 was regulated by p38-α MAPK, but not ERK or JNK, and the increase in endogenous N-SMase activity was abrogated by p38 MAPK inhibition. In addition, both p38-α MAPK and nSMase2 were implicated in the TNF-α-stimulated up-regulation of the adhesion proteins vascular cell adhesion molecule-1 (VCAM) and intercellular adhesion molecule-1 (ICAM), but this was largely independent of NF-κB activation. These data reveal p38 MAPK as an upstream regulator of nSMase2 and indicate a role for nSMase2 in pro-inflammatory responses induced by TNF-α as a regulator of adhesion proteins.
Neutral sphingomyelinases (N-SMases) are major candidates for stress-induced ceramide production. However, there is little
information on the physiological regulation and roles of the cloned N-SMase ...enzyme, nSMase2. In this study, nSMase2 was found
to translocate acutely to the plasma membrane of A549 epithelial cells in response to tumor necrosis factor α (TNF-α) in a
time- and dose-dependent manner. Additionally, TNF-α increased N-SMase activity rapidly and transiently both endogenously
and in cells overexpressing nSMase2. Furthermore, the translocation of nSMase2 was regulated by p38-α MAPK, but not ERK or
JNK, and the increase in endogenous N-SMase activity was abrogated by p38 MAPK inhibition. In addition, both p38-α MAPK and
nSMase2 were implicated in the TNF-α-stimulated up-regulation of the adhesion proteins vascular cell adhesion molecule-1 (VCAM)
and intercellular adhesion molecule-1 (ICAM), but this was largely independent of NF-κB activation. These data reveal p38
MAPK as an upstream regulator of nSMase2 and indicate a role for nSMase2 in pro-inflammatory responses induced by TNF-α as
a regulator of adhesion proteins.
PDF