AbstractThe population pharmacokinetic model reported here was developed using data from 2 phase 2 trials of irinotecan for treatment of malignant glioma to quantify the impact of concomitant therapy with enzyme‐inducing antiepileptic drugs (EIAEDs) on irinotecan pharmacokinetics. Patients received weekly irinotecan doses of 100 to 400 mg/m2, and plasma samples were collected and analyzed for irinotecan and its APC, SN‐38, and SN‐38G metabolites. Nonlinear mixed‐effects modeling was employed for population pharmacokinetic analysis. Concomitant therapy with phenytoin, phenobarbital, or carbamazepine increased the clearances of irinotecan, SN‐38, and SN‐38G but not APC. SN‐38 clearance was 2‐fold higher with concomitant EIAED use, resulting in 40% lower SN‐38 exposure. Evaluation of additional covariates revealed no clinically relevant effects of sex or concomitant corticosteroid use. The population pharmacokinetic model suggests that a 1.7‐fold increase in irinotecan dose may compensate for decreases in SN‐38 exposure in the presence of concomitant EIAEDs. Although slightly more conservative, this dose adjustment is consistent with those recommended based on increases in the maximally tolerated dose for malignant glioma patients receiving EIAEDs and may be an appropriate starting point for further investigation when extrapolating to other cancer types or alternative regimens.
Oncolytic Measles Virus Expressing the Sodium Iodide Symporter to Treat Drug-Resistant Ovarian Cancer
Abstract P2-09-07: Inhibition of aurora-A by MLN8237 decreases SMAD5 expression and increases effectiveness of chemotherapeutic agents in breast cancer cells
Abstract BACKGROUND: Breast cancer affects thousands of women each year. Epithelial to Mesenchymal transition (EMT) has been associated with increased metastatic potential of cancer cells as well as resistance to chemotherapy. Predicatively, presence of EMT leads to worse prognosis in patients with breast cancer. We have recently showed that Aurora-A plays a key role in development of EMT and increased ability of breast cancer cells for self renewal. Therefore we hypothesized that inhibition of Aurora-A in breast cancer cells will lead to increased sensitivity to chemotherapy. RESULTS: Increased Aurora-A expression, as assessed by IHC staining, in patients with locally advanced disease was associated with worse prognosis. We show that in ER+ cell line, MCF7, activating MAPK pathway through overexpression of Raf1 leads to increase in Aurora-A activity. These cells have decreased sensitivity to treatment with paclitaxel when compared to untransfected cells in MTT assays. This effect is even more exacerbated with over-expression of Aurora-A. The sensitivity to paclitaxel was restored with inhibition of Aurora-A by specific inhibitor, Alisertib. This was further explored in triple negative (MDA-MB-231) or Her-2/neu expressing (SUM149) cell lines. These cells express higher levels of Aurora-A. Inhibition of Aurora-A activity in combination with paclitaxel was superior when compared to either therapy alone. Similar effect was seen with use of anthracyclines. Inhibition of Aurora-A resulted in decreased SMAD5 expression as well as decreased Akt phosphorylation. Current studies are looking at a role of Aurora-A in activating SMAD5 and its role in resistance to chemotherapy. In vivo experiments evaluating combination therapies in breast cancer animal model are ongoing. CONCLUSIONS: Inhibition of Aurora-A by a specific inhibitor, MLN8237, resulted in decreased SMAD5 expression and increased effectiveness of chemotherapeutic agents in breast cancer cells. These results contribute to better understanding of signaling pathways involved in resistance of breast cancer cells to chemotherapy. This knowledge could be very useful in developing more effective treatments for breast cancer patients in neo-adjuvant, adjuvant and metastatic settings. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-07.
Phase II Study of Bevacizumab in Combination with Sorafenib in Recurrent Glioblastoma (N0776): A North Central Cancer Treatment Group Trial
Abstract 5562: Utility of circulating biomarkers as outcome predictors in metastatic colorectal cancer and recurrent glioblastoma multiforme patients treated with bevacizumab/sorafenib
Abstract Purpose: Surrogate biomarkers are lacking for predicting or monitoring response to anti-angiogenesis therapies. We investigated whether circulating biomarkers (CBMs) of angiogenesis (i.e., bFGF, SDF-1α, HGF, sKIT, Ang-2, and PlGF) correlated with treatment efficacy in a pooled analysis of metastatic colorectal cancer (mCRC) and recurrent glioblastoma multiforme (rGBM) patients (pts) treated with bevacizumab/sorafenib (BEV/SOR). Experimental procedures: Peripheral blood samples were obtained for CBM analyses from pts enrolled in the North Central Cancer Treatment Group (NCCTG) phase II studies N054C (mCRC, n=75, Grothey, ASCO 2010) and N0776 (rGBM, n=54, Galanis, ASCO 2010). Blood collection time points were: baseline (BL), cycle 1 day 3 (C1D3), prior to treatment cycles 2, 3, 5, 7, 9, 11, 13, and after the pt went off study. Plasma CBM levels were determined by commercially-available ELISAs (R&D Systems) and performed according to manufacturer's instructions. For each CBM, a linear regression model that adjusted for study was used to evaluate the correlation with either progression-free survival (PFS) success/failure or progression within 14 days of the last blood draw for the following measures: absolute BL levels, log2 BL levels; C1D3 log2-fold change (FC) from BL, prior to cycle 2 log2-FC from BL, last draw log2-FC from BL, and last draw log2-FC from prior draw. Results summary: There appears to be no significant difference in the PFS or overall survival (OS) between the pts on these two studies; therefore, we pooled the patients from both studies for a combined analyses. We found no difference in absolute or log2 levels for any of the CBMs during the course of BEV/SOR treatment. In these pooled analyses, we found increased absolute and increased log2 BL SDF-1α levels were significantly correlated with PFS success (p=0.023 and p=0.02, respectively). After correcting for multiple comparisons (method of Benjamini & Hochberg) the p-values <0.05 had a false-discovery-rate of 41.4%. None of the other CBM measures were significantly correlated with either PFS success/failure or progression within 14 days of the last blood draw (all p>0.10). Conclusions: This study provides preliminary evidence that SDF-1α may be a useful CBM for determining treatment efficacy in these pts treated with BEV/SOR. Further prospective validation of SDF-1α for predicting pt progression with this treatment combination in advanced disease (e.g., mCRC and rGBM) appears warranted. 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 5562. doi:1538-7445.AM2012-5562
Abstract C56: NCCTG phase I trial of everolimus (RAD001) and temozolomide (TMZ) in combination with radiation therapy (RT) in newly diagnosed glioblastoma multiforme (GBM) patients
Abstract Background: The mammalian target of rapamycin (mTOR) functions within the PI3K/Akt signaling pathway as a critical modulator of cell survival. We previously demonstrated significant synergy of the mTOR inhibitor sirolimus with RT in glioma xenografts. This Phase I study evaluated the safety and tolerability of combined therapy with the mTOR inhibitor RAD001, RT and TMZ. Methods: All patients received weekly oral RAD001, starting 1 week prior to RT/TMZ and continuing until progression, with a break from therapy between RT/TMZ and adjuvant TMZ. RAD001 was dose escalated in cohorts of 6 patients. In addition to RAD001, all pts received standard treatment with RT (60 Gy)/TMZ (75 mg/m2 daily) and adjuvant TMZ (200 mg/m2 daily × 5 every 28 days). DLTs were defined during therapy with RAD001 combined with TMZ/RT. Results: A total of 18 patients were enrolled. Combined RAD001/RT/TMZ was well tolerated at all dose levels with 1 of 6 patients with a DLT at each dose level. DLTs were Grade 3 fatigue (RAD001 25 mg/week), Grade 4 hematologic toxicity (RAD001 50 mg/week), and Grade 4 liver function elevation (RAD001 70 mg/week). With adverse event information available for all 18 patients, no grade 5 events were seen. Nine grade 4 events (thrombosis, fatigue, anemia, neutropenia, thrombocytopenia, leukopenia, SGPT (ALT), SGOT (AST), bilirubin elevation) were seen in 3 patients. On the basis of these results, the recommended Phase II dose currently being tested is RAD001 70 mg/week in combination with standard RT/TMZ and adjuvant TMZ. FDG PET scans were also obtained prior to the first dose of RAD001 and within 24 hours of the second dose of RAD001, prior to starting RT or TMZ, and changes in maximum standard uptake values (SUV) were compared between scans for each patient. Two patients at 25 mg RAD001/week had a 21% and 24% change in SUV, and 2 patients receiving 70 mg/week had a change in SUV uptake of −33% and −16%. Additional follow-up will be required to evaluate whether these SUV changes are associated with outcome. Conclusions: RAD001 in combination with RT/TMZ and adjuvant TMZ was well tolerated, and the imaging results support continued evaluation of PET imaging as an early predictor of response to therapy. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C56.
Effective Radiovirotherapy for Malignant Gliomas by Using Oncolytic Measles Virus Strains Encoding the Sodium Iodide Symporter (MV-NIS)