Citations

AbstractSrc tyrosine kinases are overexpressed in pancreatic cancers, and the oral Src inhibitor saracatinib has shown antitumor activity in preclinical models of pancreas cancer. We performed a CTEP‐sponsored Phase II clinical trial of saracatinib in previously treated pancreas cancer patients, with a primary endpoint of 6‐month survival. A Simon MinMax two‐stage phase II design was used. Saracatinib (175 mg/day) was administered orally continuously in 28‐day cycles. In the unselected portion of the study, 18 patients were evaluable. Only two (11%) patients survived for at least 6 months, and three 6‐month survivors were required to move to second stage of study as originally designed. The study was amended as a biomarker‐driven trial (leucine rich repeat containing protein 19 [LRRC19] > insulin‐like growth factor‐binding protein 2 [IGFBP2] “top scoring pairs” polymerase chain reaction [PCR] assay, and PIK3CA mutant) based on preclinical data in a human pancreas tumor explant model. In the biomarker study, archival tumor tissue or fresh tumor biopsies were tested. Biomarker‐positive patients were eligible for the study. Only one patient was PIK3CA mutant in a 3′ untranslated region (UTR) portion of the gene. This patient was enrolled in the study and failed to meet the 6‐month survival endpoint. As the frequency of biomarker‐positive patients was very low (<3%), the study was closed. Although we were unable to conclude whether enriching for a subset of second/third line pancreatic cancer patients treated with a Src inhibitor based on a biomarker would improve 6‐month survival, we demonstrate that testing pancreatic tumor samples for a biomarker‐driven, multicenter study in metastatic pancreas cancer is feasible.

Abstract A hypoxic microenvironment is believed to be a characteristic of solid tumors including pancreatic adenocarcinoma (PAC) and is associated with resistance to chemotherapy. The hypoxia-activated prodrug, TH-302, is designed to specifically target the hypoxic microenvironment. Combining G with TH-302 may enable the targeting of both the normoxic and hypoxic regions of PAC. TH-302 was investigated with full-dose G as part of a Phase 1/2 study with a 21% response, median PFS and OS of 5.9 and 8.5 months, respectively, and one-year survival of &gt;40%. Based upon these data, a randomized Phase 2B study (NCT01144455) was conducted to assess the benefit of G+T to standard dose G for first-line therapy of PAC. An open-label multi-center study of two dose levels of TH-302 (240 mg/m2 or 340 mg/m2) in combination with G versus G alone (randomized 1:1:1) was initiated in June 2010. G (1000 mg/m2) and T were administered IV over 30-60 minutes on Days 1, 8 and 15 of a 28-day cycle. Patients on the G arm could crossover after progression and be randomized to a G+T arm. The primary efficacy endpoint is a comparison of progression-free survival (PFS) between the combination arms and G alone (80% power to detect 50% improvement in PFS with one-sided alpha of 10%). 214 pts (69 G: 71 G+T240: 74 G+T340) with advanced PAC including 77% distant metastases, 62% involving liver and 11% with prior adjuvant tx; median age: 65 (range 29-86); 126 M/88 F; 79/128 ECOG 0/1. Median cycles received: G - 4, G+T240 - 5, G+T340 - 6. Median PFS was 3.6 mo in G vs 5.6 mo in G+T arms with HR of 0.61 (95% CI: 0.43 - 0.87) and logrank p-value of 0.005. Median PFS in G + T340 was 6.0 mo. RECIST best response was 12% in G, 17% in G+T 240 and 27% in G+T340. 153 (71%) patients had elevated CA19-9 and follow-up. CA19-9 decreases were significantly greater in the G+T groups and greatest in the G+T340 arm which had 37 of 53 (70%) pts with a greater than 50% CA19-9 decrease. One death (suicide) was considered possibly related to study drug. Adverse events leading to discontinuation were: 16% G, 15% G+T240 and 11% G+T340. Serious adverse events were balanced across the treatment arms. The most common non-laboratory events, fatigue (49%), nausea (43%), constipation (34%) and peripheral edema (38%), were similar across groups. Rash (14% G, 39% G+T240 and 45% G+T340) and stomatitis (6% G, 17% G+T240 and 36% G+T340) were significantly greater with G+T combination but no Grd 4 (4 pts with Grade 3). Grd 3/4 thrombocytopenia (11% G, 39% G+T240 and 59% G+T340) and Grd 3/4 neutropenia (28% G, 56% G+T240 and 59% G+T340) were higher with G+T. G+T combination with full dose G improved the efficacy of G with significantly longer PFS, higher response rate and greater CA19-9 declines. The G+T combination was well tolerated. Skin and mucosal toxicity and myelosuppression were the most common related adverse events with no increase in treatment discontinuation. 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 LB-121. doi:1538-7445.AM2012-LB-121

Abstract Background: Colon cancer is categorized by the acquisition of a number of molecular alterations in both oncogenes and in tumor suppressor genes. Although cMYC alterations have been reported in colon cancer cell lines, little other information exists in primary colon tumors. We sought to determine the frequency of cMYC amplification in primary colon cancer and its relationship to other well defined colon tumor alterations. Methods: An initial set of 392 tumors were evaluated. All samples were tested for the BRAF V600E mutation and all were classified as proficient mismatch repair (pMMR) based on both IHC and microsatellite analysis of tumor tissue. A second set of 522 tumors was selected to replicate associations identified in the first set of samples. Similar to the initial cohort, both the BRAF V600E and the mismatch repair status of the tumors were assessed. The second cohort, however, included tumors that were both pMMR and dMMR. In both sets of samples, fluorescent in situ hybridization was used to evaluate cMYC gene amplification. Results: In cohort 1, cMYC amplification was observed in 15 of the 362 (4%) pMMR tumors successfully analyzed (Table 1). cMYC amplification was detected in 10 of 323 (3%) tumors with normal BRAF status vs. 5 of 39 (13%) tumors with altered BRAF status (p=0.015). In the second cohort, cMYC amplification was found in 20 of the 522 (4%) tumors. Only 1 of the 152 (&lt;1%) dMMR tumors had cMYC amplification vs. 19 of the 370 (5%) pMMR tumors (p=0.012). Of the pMMR tumors, cMYC amplification was detected in 13 of 333 (4%) tumors with normal BRAF status vs. 6 of 37 (16%) tumors with altered BRAF status (p=0.007), nearly identical to the first group. Conclusion: cMYC amplification in colon cancer is an infrequent event. However, when present, cMYC amplification occurs almost exclusively in tumors that are pMMR. Additionally, among pMMR tumors, cMYC amplification is associated with the presence of the BRAF V600E mutation. 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 1151. doi:1538-7445.AM2012-1151

Abstract Background. Autophagy maintains energy metabolism and enables tumor cell survival during cellular stress. Beclin 1 is involved in autophagosome formation during which membrane-bound LC3 binds to p62/sequestosome 1. We reported that ectopic p62 can promote 5-fluorouracil-induced cell death (JBC 286:40002-12, 2011). It is unknown whether these autophagy markers can predict clinical outcome. Materials & Methods. Beclin 1, LC3B, and p62 proteins were analyzed by immunohistochemistry in tissue microarrays containing stage II and III colon carcinomas (N=151) from patients receiving 5-FU or surgery alone. The mean weighted score (intensity x extent) was dichotomized for survival analysis using Cox models. Results. Increased levels of cytoplasmic LC3, Beclin 1, and p62 expression were detected in 21%, 14%, and 68% of cancers, respectively, and were not associated with tumor site, stage or grade. By multivariable analysis, increased LC3 was significantly associated with worse disease-free survival (DFS) (p=0.022), but not overall survival (OS) [p=0.069](Table). Beclin 1 was not prognostic, but increased p62 was significantly associated with improved DFS (p=0.038), but not OS (p= 0.176)[Table]. When restricted to 5-FU-treated patients, increased LC3 was associated with worse DFS [HR= 2.38 (1.19, 4.75, p=0.020), elevated Beclin 1 predicted worse OS [HR=2.83 (1.27, 6.34), p = 0.019], and p62 was not prognostic. Conclusion. LC3 and Beclin 1 overexpression were independently associated with adverse outcome. Increased p62 was associated with better outcome consistent with its ability to promote cell death. These data support strategies to inhibit autophagy for therapeutic advantage. 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 4112. doi:1538-7445.AM2012-4112