Grothey, Axel

LBA385 Background: Regorafenib (BAY 73-4506) is an oral multikinase inhibitor of a broad range of angiogenic, oncogenic, and stromal kinases. The phase III CORRECT trial was conducted to evaluate efficacy and safety of regorafenib in pts with mCRC who had progressed after all approved standard therapies. Methods: Enrollment criteria included documented mCRC and progression during or ≤3 months after last standard therapy. Pts were randomized 2:1 to receive regorafenib (160 mg od po, 3 weeks on/1 week off) plus BSC, or placebo (PL) plus BSC. Pts continued on treatment until progression, death, or unacceptable toxicity. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR), safety, and quality of life. Results: From May 2010 to March 2011, 760 pts were randomized (regorafenib: 505; PL: 255). Baseline characteristics were balanced between two arms. Preliminary results are available from a pre-planned formal interim analysis. The estimated hazard ratio (HR) for OS was 0.773 (95% CI: 0.635, 0.941; 1-sided p=0.0051). Median OS was 6.4 mos (95% CI: 5.9, 7.3) for regorafenib and 5.0 mos (95% CI: 4.4, 5.8) for PL. The estimated HR for PFS was 0.493 (95% CI: 0.418, 0.581; 1-sided p < 0.000001). Median PFS was 1.9 mos (95% CI: 1.88, 2.17) for regorafenib and 1.7 mos (95% CI: 1.68, 1.74) for PL. ORR was 1.6% for regorafenib and 0.4% for PL. DCR was 44% for regorafenib and 15% for PL (p < 0.000001). Since the prespecified OS efficacy boundary was crossed (nominal α: 0.0093), the Data Monitoring Committee recommended to unblind the study and pts on PL were allowed to cross over to regorafenib. The most frequent grade 3+ AEs in the regorafenib arm were hand-foot skin reaction (17%), fatigue (15%), diarrhea (8%), hyperbilirubinemia (8%), and hypertension (7%). Updated results will be presented. Conclusions: Statistically significant benefit in OS and PFS was observed for regorafenib over PL in pts with mCRC who have failed all approved standard therapies. No new or unexpected safety signal was found.

446 Background: MutKRAS and mutBRAF are important predictive and prognostic markers, respectively, in colorectal cancer (CRC). However, little is known about why some tumors harbor these mutations. N0147 is a phase III adjuvant trial for stage III CRC patients (N=3397) in which patients completed questionnaires and tumor variables and KRAS/BRAF mutation status was assessed. Methods: 2,323/3,397 patients who were enrolled prior to a 2008 amendment requiring KRAS testing completed a Patient Questionnaire. Primary tumors were assessed for mutKRAS and mutBRAF using standard methods; MMR status was determined using IHC. Multivariate analysis was performed to identify predictors of mutation status. Results: 60% and 86% of mutKRAS and mutBRAF tumors were right-sided, respectively. MutKRAS was less likely if there was a family history of CRC and in ever-smokers, and was nearly mutually exclusive with mutBRAF. MutBRAF was associated with deficient MMR (dMMR), high grade histology, and 4+ positive lymph nodes at surgery. MutBRAF was more likely in patients age > 70, retired persons, ever-smokers, but was less likely in non-whites and men. Conclusions: Smoking, family history of CRC, and dMMR status are associated with lower frequency of mutKRAS , but higher mutBRAF. Both mutations tend to be right sided, and mutBRAF is more common in the elderly, females, and non-Hispanic whites. [Table: see text]

AbstractBackground.Preclinical and epidemiological data suggest that metformin might have antineoplastic properties against colon cancer (CC). However, the effect of metformin use on patient survival in stage III CC after curative resection is unknown. The survival outcomes were comparable regardless of the duration of metformin use.Patients and Methods.Before randomization to FOLFOX (folinic acid, 5-fluorouracil, oxaliplatin) with or without cetuximab, 1,958 patients with stage III CC enrolled in the N0147 study completed a questionnaire with information on diabetes mellitus (DM) and metformin use. Cox models were used to assess the association between metformin use and disease-free survival (DFS), overall survival (OS), and the time to recurrence (TTR), adjusting for clinical and/or pathological factors.Results.Of the 1,958 patients, 1,691 (86%) reported no history of DM, 115 reported DM with metformin use (6%), and 152 reported DM without metformin use (8%). The adjuvant treatment arms were pooled, because metformin use showed homogeneous effects on outcomes across the two arms. Among the patients with DM (n = 267), DFS (adjusted hazard ratio [aHR], 0.90; 95% confidence interval [CI], 0.59–1.35; p = .60), OS (aHR, 0.99; 95% CI, 0.65–1.49; p = .95), and TTR (aHR, 0.87; 95% CI, 0.56–1.35; p = .53) were not different for the metformin users compared with the nonusers after adjusting for tumor and patient factors. The survival outcomes were comparable regardless of the duration of metformin use (&lt;1, 1–5, 6–10, ≥11 years) before randomization (ptrend = .64 for DFS, ptrend = .84 for OS, and ptrend = .87 for TTR). No interaction effects were observed between metformin use and KRAS, BRAF mutation status, tumor site, T/N stage, gender, or age.Conclusions.Patients with stage III CC undergoing adjuvant chemotherapy who used metformin before the diagnosis of CC experienced DFS, OS, and TTR similar to those for non-DM patients and DM patients without metformin use.

Abstract Background. The Avastin® Registry: Investigation of Effectiveness and Safety (ARIES) study is a prospective, community-based observational cohort study that evaluated the effectiveness and safety of first-line treatment patterns, assessing the impact of chemotherapy choice and treatment duration. Methods. The ARIES study enrolled patients with metastatic colorectal cancer (mCRC) receiving first-line chemotherapy with bevacizumab and followed them longitudinally. The protocol did not specify treatment regimens or assessments. Analyses included all patients who initiated bevacizumab in combination with either first-line oxaliplatin with infusional 5-fluorouracil and leucovorin (FOLFOX) or irinotecan with infusional 5-fluorouracil and leucovorin (FOLFIRI). Progression-free survival (PFS) and overall survival (OS) times were estimated using Kaplan–Meier methods. Hazard ratios (HRs) were estimated with multivariate Cox regression analysis, adjusting for potential confounding factors. Results. In total, 1,550 patients with first-line mCRC were enrolled (median follow-up, 21 months) and most received FOLFOX–bevacizumab (n = 968) or FOLFIRI–bevacizumab (n = 243) as first-line therapy. The baseline characteristics and median treatment duration were generally similar between subgroups. There were no significant differences in the median PFS (10.3 months vs. 10.2 months) or OS (23.7 months vs. 25.5 months) time between the FOLFOX–bevacizumab and FOLFIRI–bevacizumab subgroups, respectively, by unadjusted analyses. Multivariate analyses showed FOLFIRI–bevacizumab resulted in a similar PFS (HR, 1.03; 95% confidence interval [CI], 0.88–1.21) and OS (HR, 0.95; 95% CI, 0.78–1.16) outcome as with FOLFOX–bevacizumab. The incidence proportions of bevacizumab-associated adverse events were similar for FOLFOX- and FOLFIRI-based therapies. Conclusions. In first-line mCRC patients, the FOLFOX–bevacizumab and FOLFIRI–bevacizumab regimens were associated with similar treatment patterns and clinical outcomes.

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 &lt;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&gt;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 Purpose: We examined the frequency, tumor characteristics, and prognostic impact of HER2 protein expression and gene amplification in patients with curatively resected esophageal adenocarcinoma (EAC). Experimental Design: HER2 expression was analyzed by immunohistochemistry (IHC) in surgical EAC specimens (n = 713). Gene amplification was examined by FISH in a large subset (n = 344). Most tumors were T3–4 (66%) or node positive (72%); 95% were located in the esophagus or gastroesophageal junction. No patient received neoadjuvant therapy. Cox models were used. Results: Overall, 17% of EACs were HER2 positive (i.e., IHC3+ or IHC2+ with amplification), with strong agreement between HER2 amplification (HER2/CEP17 ratio ≥2) and expression (κ = 0.83). HER2 positivity was significantly associated with lower tumor grade, less invasiveness, fewer malignant nodes, and the presence of adjacent Barrett's esophagus (BE). EACs with BE had higher odds of HER2 positivity than EACs without BE, independent of pathologic features [OR = 1.8 (95% CI: 1.1–2.8), P = 0.014]. Among all cases, HER2 positivity was significantly associated with disease-specific survival (DSS) in a manner that differed by the presence or absence of BE (Pinteraction = 0.0047). In EACs with BE, HER2 positivity was significantly associated with improved DSS [HR = 0.54 (95% CI: 0.35–0.84), P = 0.0065] and overall survival (P = 0.0022) independent of pathologic features, but was not prognostic among EACs without BE. Conclusions: HER2 positivity was shown in 17% of resected EACs and associated with reduced tumor aggressiveness. EACs with BE had nearly twice the odds of being HER2 positive and, within this subgroup, HER2 positivity was independently associated with improved survival. Clin Cancer Res; 18(2); 546–54. ©2012 AACR.

Abstract Detection of guanylyl cyclase C mRNA in lymph nodes of resected stage II colorectal cancer is highly correlated with the risk of tumor recurrence. If validated, these results could have significant implications for the selection of patients for adjuvant therapy in this disease. Clin Cancer Res; 17(10); 3053–5. ©2011 AACR.