Erlichman, Charles

Abstract Background: Based upon preclinical synergy and prior phase 1 study results, the clinical efficacy of flavopiridol combined with cisplatin was assessed in patients with recurrent ovarian and primary peritoneal cancers. Methods: A two cohort phase 2 trial of cisplatin (60 mg/m2 IV) followed by flavopiridol (100 mg/m2 IV, 24 h continuous infusion; 21 day cycles) was undertaken in patients with recurrent platin-sensitive or platin-resistant ovarian/primary peritoneal cancers (defined by disease progression > vs. <6 months following platin-based therapy). Measurable disease (RECIST criteria) – or evaluable disease plus CA125 >2X the post-treatment nadir – was required, as was ECOG performance <2 and exposure to only one prior treatment regimen. Results: Forty-five patients were enrolled between April 20, 2004 and March 4, 2010 – 40 platin-resistant patients (Group 1), and 5 platin-sensitive patients (Group 2). In Group 1, the median number of treatment cycles was 3 (range 2-12); 39 of the 40 eligible patients have now discontinued treatment. While only 10% of all patients incurred grade 4 toxicities, grade 3 toxicities were seen in the majority (65%). The most frequent grade 3 and 4 toxicities were neutropenia (all grade 3, 17.5%); nausea (12.5%); vomiting, fatigue, thrombosis, anemia (10% each). Sensory neuropathy, grade 1 or 2, was observed in 75% of all patients – with grade 3 and 4 neuropathy not observed primarily due to pre-specified aggressive dose reductions. Six patients (15%) in Group 1 achieved a confirmed response (1 CR, 5 PR), with a median response duration of 119 days (range 84-212). Ten additional Group 1 patients (32.5%) experienced maintained stable disease. Median Group 1 overall time to progression was 3.7 months; overall survival was 17.2 months. Pilot assessment of attained ascites flavopiridol level and sensitivity of patient ascitic tumor cells to flavopiridol confirmed that patient flavopiridol levels were consistent with observed clinical antitumor efficacy. In Group 2, although 2 of 5 patients also responded (40%; 2 PR), the cohort was closed due to poor accrual. Conclusions: The combination of flavopiridol and cisplatin has promising clinical activity in both platin-sensitive and platin-resistant ovarian and primary peritoneal cancers. Supported in part by NCI CA097129, CA15083 and CM62205; clinicaltrials.gov identifier NCT00083122 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4712. doi:10.1158/1538-7445.AM2011-4712

Abstract Background: ABT-888 is an inhibitor of poly(ADP-ribose) polymerase1 (PARP1) and PARP2, two highly conserved enzymes implicated in DNA repair, maintenance of genomic stability, and regulation of transcription. Topotecan (TPT) is a water soluble camptothecin derivative with antitumor activity against ovarian tumors. The combination of ABT-888 with TPT is under investigation in phase I trials because PARP inhibition sensitizes tumors cells to TPT in vitro and in vivo. In those trials, the pharmacokinetics of TPT and ABT-888 are being studied to determine if ABT-888 levels are sufficient to modulate PARP activity and to investigate the potential interaction between TPT and ABT-888. Methods: Advanced cancer patients with ECOG performance scores 0-2, adequate hematological, renal and hepatic function were treated with ABT-888 on days 1-3, 8-10, and 15-17 every 28 days. Topotecan was administered on days 2, 9 and 16 every 28 days. DLTs were defined as grade 4 neutropenia, grade 4 thrombocytopenia, grade 4 anemia or ≥ grade 3 non-hematologic toxicities despite maximal supportive care. ABT-888 and Toptoecan pharmacokinetics were characterized in all patients. Analysis of urinary recovery is ongoing. Results: In this ongoing Phase I trial, 13 female patients with ovarian (n=12) or breast (n=1) cancer have been enrolled to date and pharmacokinetic data is available for 12 of those patients. ABT-888/TPT dose levels are: Level 1- 10 mg/ 2 mg/m2, Level 2- 20 mg/2 mg/m2, Level 3- 10 mg/3 mg/m2, and Level 4- 20 mg/3 mg/m2. The combination of ABT-888 with topotecan has been tolerable, with no dose limiting toxicity, and dose escalation continues at dose level 5. Topotecan t1/2 and clearance values were 3.0 ± 0.5 hrs and 9.50 ± 1.51 L/hr/m2 when administered alone, and were not affected by administration with ABT-888. When administered alone, ABT-888 t1/2, Cmax, AUC0-∞ values after the 10 mg dose were 8.2 ± 2.4 hrs, 432 ± 217 nM, and 2568 ± 1300 nM*hr, respectively. ABT-888 t1/2, Cmax, AUC values after the 20 mg dose were 5.7 ± 3.1 hrs, 600 ± 165 nM, and 3870± 934 respectively. When administered with TPT, ABT-888 t1/2, Cmax, AUC values after the 10 mg dose were 7.2 ± 2.1 hrs, 412 ± 283 nM, and 2705± 1089 nM*hr are: nM*hr respectively. ABT-888 t1/2, Cmax and AUC values after the 20 mg dose combined with TPT were 5.8 ± 2.2 hrs, 664 ± 97.6 nM, and 4283± 936 nM*hr respectively. Conclusions: Plasma clearance of TPT and ABT-888 does not appear to be altered when they are administered together. The effect of co-administration of these agents on renal clearance is presently under investigation and those results will be presented. This work was supported by NIH grants R25 GM75148-04, U01CA069912-16S and MM01-RR00585. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1301. doi:10.1158/1538-7445.AM2011-1301

Abstract Src transduces activated HER tyrosine kinase and phosphorylates HER to further increase its activity. Src also is involved in osteoclast differentiation. We hypothesized that combining a HER tyrosine kinase inhibitor with a Src inhibitor would result in increased therapeutic activity. To address this hypothesis we performed a phase I trial of D and L to: 1)determine the maximally tolerated dose (MTD) of D combined with L; 2)describe the toxicities associated with this combination; 3)assess the pharmacokinetic (PK) interaction of L and D; 4) assess the effect of the L and D combination on circulating tumor cells (CTC) and on osteoclast precursor activation; 5)study the association of toxicity and/or tumor response with PK, and/or pharmacodynamic parameters; and 6)describe the responses of this combination. Eligibility criteria included ≥ 18 years of age, incurable solid tumors not amenable to other therapies, ANC ≥ 1500/ L, PLT ≥ 100,000/ L, total bilirubin ≤ ULN, AST ≤ 3 × ULN or AST ≤5 × ULN if liver involvement, creatinine ≤ 1.5 × ULN, Hgb ≥ 9.0 g/dL, K+ and Mg++ WNL, life expectancy ≥ 12 weeks, ejection fraction > 50%, ECOG PS 0–2, and able to swallow pills whole. In addition to standard phase I exclusion criteria patients could not have received erlotinib, sunitinib, sorafenib, gefitinib, imatinib ≤ 4 weeks prior to registration. Each agent was administered once daily on a 28 day schedule. At the MTD patients were treated with D day 1, and day 9–28 and L day 2–28 to assess PK interaction. Dose levels (mg) were #1 D 70, L 1000, #2 D 100, L 1000, #3 D 140, L 1000. 12 patients were entered on the dose escalation portion of the trial and 15 were entered at the MTD. 5 patients entered at the MTD are too early to be fully evaluable. Characteristics of evaluable patients were: median age, 63; 46% female; PS 0 (64%) 1 (27%), 1 (9%); ≥ 3 prior chemotherapies (59%). DLT was seen in 2 patients at # 3 (1 patient, grade 3 hypermagnesemia, 1, grade 3 rash) and 1 patient at # 2 (grade 3 dyspnea). The MTD was determined to be # 2. No grade 4 or 5 events have been observed in this study. 6 patients had stable disease in the dose escalation cohort. 1 (RCC) was stable disease for 6 cycles, 2 (colorectal) were stable for 5 cycles, 1 (esophagus) was stable for 3 cycles, and 2 (GIST & leiomyosarcoma) were stable for 2 cycles. Analysis of drug levels, CTCs and circulating osteoclast precursors is ongoing. There was a consistent increase in the percentage of CD11b (monocyte/macrophage/osteoclast lineage marker) positive cells in circulation as treatment progressed. However, the late osteoclast lineage marker c-Fms was not similarly increased, suggesting that the elevated CD11b reflects an inflammatory response and not activation of osteoclastogenesis. D and L is a tolerable combination at nearly full doses of each drug. Funded by a grant from Glaxo Smith Kline and Bristol Myers Squibb. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B56.

The development of subspecialty tumor groups for uncommon malignancies represents an effective approach to building experience, increasing patient volumes and referrals, and fostering development of increased therapeutic options and clinical trials for patients afflicted with otherwise historically neglected cancers.

Abstract 5-Fluorouracil (5-FU) and 5-fluorodeoxyuridine (FdUrd, floxuridine) have activity in multiple tumors, and both agents undergo intracellular processing to active metabolites that disrupt RNA and DNA metabolism. These agents cause imbalances in deoxynucleotide triphosphate levels and the accumulation of uracil and 5-FU in the genome, events that activate the ATR- and ATM-dependent checkpoint signaling pathways and the base excision repair (BER) pathway. Here, we assessed which DNA damage response and repair processes influence 5-FU and FdUrd toxicity in ovarian cancer cells. These studies revealed that disabling the ATM, ATR, or BER pathways using small inhibitory RNAs did not affect 5-FU cytotoxicity. In stark contrast, ATR and a functional BER pathway protected FdUrd-treated cells. Consistent with a role for the BER pathway, the poly(ADP-ribose) polymerase (PARP) inhibitors ABT-888 (veliparib) and AZD2281 (olaparib) markedly synergized with FdUrd but not with 5-FU in ovarian cancer cell lines. Furthermore, ABT-888 synergized with FdUrd far more effectively than other agents commonly used to treat ovarian cancer. These findings underscore differences in the cytotoxic mechanisms of 5-FU and FdUrd and suggest that combining FdUrd and PARP inhibitors may be an innovative therapeutic strategy for ovarian tumors. Cancer Res; 71(14); 4944–54. ©2011 AACR.

Abstract We have demonstrated that crosstalk between the Hedgehog-GLI-GLI and EGFR signaling pathway exists and contribute to pancreatic tumorigenesis. This interaction can be abrogated by targeting both pathways simultaneously and results in a synergistic antitumor effect in vitro and in vivo in pancreatic tumor models. Based on these results we have undertaken a phase I trial of GDC-0449 (an orally administered Hedgehog pathway inhibitor) and erlotinib (EGFR tyrosine kinase inhibitor to: 1) determine the maximally tolerated dose (MTD) of GDC-0449 combined with erlotinib in unresectable solid tumors; 2) describe the adverse events associated with this treatment combination; 3) describe the responses of this treatment combination; and 4) to assess the effect of the erlotinib and GDC-0449 combination on selected biomarkers in circulating tumor cells (CTCs), tumor biopsies, and FDG-PET in a cohort of patients with metastatic pancreatic cancer patients treated at the MTD. During the dose escalation portion of the trial, eligible patients receive GDC-0449 150 mg p.o. daily and erlotinib 50, 75, 100, or 150 mg daily p.o. at dose levels 1, 2, 3, and 4 respectively. Eligibility criteria include: histologic proof of solid tumors that are unresectable, not amenable to any other standard therapies, or patient refused standard therapy,; ANC ≥> 1500/μL; PLT ≥> 100,000/ μL; Total bilirubin ≤< upper limit of normal (ULN); AST ≤< 3 x ULN; Creatinine ≤< 1.5 x ULN; Hemoglobin ≥> 9.0 g/dL; INR within normal limits (Cohort II [MTD Cohort] only); ECOG performance status (PS) 0, 1 or ≤ 2. For the MTD cohort, only patients with metastatic adenocarcinoma of the pancreas without prior systemic therapy for metastatic disease and tumor amenable to biopsies are eligible. Toxicity assessment is performed at each 28-day treatment cycles and response assessment every second treatment 28 day cycle. 12 patients have been entered-pancreas (3), colorectal (3), neuroendocrine (2), scc anus (2), gallbladder (1), thymoma (1). No dose-limiting toxicity (DLT) was reported at dose level 4. At the MTD, up to 20 patients with previously untreated metastatic pancreatic cancer will be entered to assess the biologic effect of GDC-0449+erlotinib. Pre- and post- treatment biopsies of metastases and FDG-PET will be performed. Weekly collection of CTCs will be undertaken and immunofluorescence microscopy of total & phosphoMAPK, EGFR, AKT, PATCHED1, GLI1, BCL-2, and quantitative PCR (Q-PCR) of PATCHED1, GLI1, and its target genes (BCL-2, BFL-1/A1, 4-1BB) will be performed. In addtion, total & phosphoMAPK, EGFR, and AKT, as well as PATCHED1, GLI1, BCL-2 by immunohistochemistry and Q-PCR of PATCHED1, GLI1, BCL-2, BFL-1/A1, 4-1BB will be analyzed in tumor biopsies. Supported by CA69912, CA136526 and CA102701. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1807.

Abstract Preclinical investigations have identified insulin-like growth factor (IGF) signaling as a key mechanism for cancer growth and resistance to clinically useful therapies in multiple tumor types including breast cancer. Thus, agents targeting and blocking IGF signaling have promise in the treatment of solid tumors. To identify possible mechanisms of resistance to blocking the IGF pathway, we generated a cell line that was resistant to the IGF-1R/InsR benzimidazole inhibitors, BMS-554417 and BMS-536924, and compared expression profiles of the parental and resistant cells lines using Affymetrix GeneChip Human Genome U133 arrays. Compared with MCF-7 cells, breast cancer resistance protein (BCRP) expression was increased 9-fold in MCF-7R4, which was confirmed by immunoblotting and was highly statistically significant (P = 7.13E-09). BCRP was also upregulated in an independently derived resistant cell line, MCF-7 924R. MCF-7R4 cells had significantly lower intracellular accumulation of BMS-536924 compared with MCF-7 cells. Expression of BCRP in MCF-7 cells was sufficient to reduce sensitivity to BMS-536924. Furthermore, knockdown of BCRP in MCF-7R4 cells resensitized cells to BMS-536924. Four cell lines selected for resistance to the pyrrolotriazine IGF-1R/InsR inhibitor, BMS-754807, did not have upregulation of BCRP. These data suggest that benzimidazole IGF-1R/InsR inhibitors may select for upregulation and be effluxed by the ATP-binding cassette transporter, BCRP, contributing to resistance. However, pyrrolotriazine IGF-1R/InsR inhibitors do not appear to be affected by this resistance mechanism. Mol Cancer Ther; 10(1); 117–25. ©2011 AACR.

Abstract Abstract #2149 Background: Inhibitors of the insulin-like growth factor 1 receptor (IGF-1R) are currently undergoing clinical testing. Preclinical investigations have identified IGF-1 signaling as a key mechanism for breast cancer growth and resistance to clinically useful therapies, including tamoxifen and trastuzumab. Thus, agents targeting IGF-1R have promise in the treatment of breast cancer. Determining mechanisms that can confer resistance to these agents may aid their clinical development.
 Methods: To understand factors may be important in predicting sensitivity to targeting the IGF-1 signaling pathway, we developed a cell line (MCF-7R4) that is resistant to BMS-554417, a small molecule, dual-kinase inhibitor of IGF-1R and insulin receptor (InsR). Compared with the parental MCF-7 cells, MCF-7R4 cells are 40- to 50-fold resistant to BMS-554417 and cross-resistant to the similar compound BMS-536924. The expression profiles of MCF-7R4 and that of MCF-7 were compared using Affymetrix GeneChip Human Genome U133 Plus 2.0 Arrays. Intracellular concentrations of BMS-536924 were examined by reverse phase high performance liquid chromatography. BMS-536924 cellular accumulation in vitro was visualized by fluorescence microscopy using a DAPI filter set. MCF-7 cells stably transfected with either the empty mammalian expression vector pcDNA (MCF-EV) or full length BCRP (MCF-BCRP) were examined for sensitivity to BMS 536924 by MTS assays.
 Results: Compared to MCF-7 cells, BCRP expression was increased 9-fold in MCF-7R4, which was highly statistically significant by t-test (p= 7.13E-09). Little change was observed in other ABC transporter proteins, including ABCB1. No change was observed in IGF-1R or InsR expression. BCRP overexpression in MCF-7R4 cells was confirmed by western blotting. MCF-7R4 cells had significantly lower intracellular accumulation of BMS-536924 compared to MCF-7 cells. Confirming these results, MCF-BCRP cells were significantly less sensitive to the cytoxic effects of BMS-536924 cells than MCF-EV cells.
 Conclusions: BCRP expression was stimulated by prolonged exposure of MCF-7 cells to BMS-554417. Upregulation of BCRP is one of the most significant changes observed in MCF-7R4 cells in comparison to parental cells. BCRP expression decreased cellular exposure to BMS-536924 and was sufficient to confer resistance. These data suggest that BSM-536924 is a substrate for BCRP-mediated efflux. Expression of BCRP may be important in de novo and acquired resistance to benzimidazole –based inhibitors of IGF-1R/InsR. Supported in part by the Mayo Clinic Breast SPORE (CA116201-03), NIH K12 (CA090628-05) and the Mayo Clinic Cancer Center (CA15083). Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2149.