Citations

3520 Background: Duration of adjuvant FOLFOX or CAPOX for stage III CC is being guided by pt stratification into low (T1-3N1) and high (T4 or N2) risk groups based on the IDEA study. We determined the relative contributions of clinical and molecular features for prediction of time-to-recurrence (TTR) and survival after recurrence (SAR) within each risk group. Methods: Stage III CC (N=5,430) from 2 trials of adjuvant FOLFOX ± cetuximab with similar outcome by study arm [NCCTG N0147 (Alliance), PETACC-8] were used. Tumors were analyzed for mismatch repair (dMMR vs pMMR), mutations in KRAS (exon 2) and BRAFV600E. Median pt follow-up was 83.4 months. Relative contributions to predicting outcome were assessed using χ2 (Harrell’s rms) based on multivariable (MV) Cox models. Results: N (50.8%) and T (31.8%) stage were the top two contributors to prediction of TTR which supports risk grouping. High risk (n=2566) vs low risk (n=2774) pts had poorer TTR (HR 2.7, 95% CI, 2.4-3.0) and SAR [HR 1.6 (1.4-1.9)], both p<.0001. TTR: KRAS contributed the most to predicting TTR among high (58.6%) and low (51.1%) risk pts (Table). Contribution of MMR (16%) to predicting TTR was limited to low risk pts. Contribution of BRAFV600E to TTR was nearly 3-fold increased in high vs low risk pts. SAR: BRAFV600E contributed the most to predicting SAR, especially in high vs low risk pts (2-fold increase). Tumor sidedness and performance status (PS) were key contributors to SAR, but not TTR. MV associations: TTR: low risk, KRAS [HR 1.7 (1.4-2.3], MMR [HR 0.55 (.35-.87), gender (M/F) [HR 1.3 (1.0-1.5)], all p<.04]; high risk: BRAF [HR 1.3 (1.1-1.7)], sidedness (R vs L) [HR 1.14 (1.0-1.3)], KRAS [HR 1.4 (1.2-1.6)], all p<.04]. SAR: BRAF, sidedness, PS (all p<.05). Conclusions: KRAS mutation was the strongest predictor of shorter TTR in both risk groups whereas BRAFV600E was the primary driver of SAR, especially in high risk pts. Support: U10CA180821, U10CA180882, U24CA196171; BMS, Pfizer, Sanofi. NCT00079274.[Table: see text]

3502 Background: DFS with 3 years median follow-up (3yDFS) was validated as a surrogate for OS with 5 years median follow-up (5yOS) in adjuvant chemotherapy CC trials prior. Recent data showed improved survival after recurrence and OS, over time, in pts who received adjuvant FOLFOX. Hence, re-evaluation of the association between DFS and OS, as well as the optimal follow-up of OS to aid its utility in future adjuvant trials is needed. Methods: Individual patient data from 8 randomized adjuvant studies conducted from 1998-2009 were included; 3 trials tested anti-VEGF or anti-EGFR agents. Trial-level surrogacy examining the correlation of treatment effect estimates (i.e. hazard ratios) of 3yDFS and 5y to 8yOS was evaluated using both linear regression (R2WLS) and Copula bivariate (R2Copula) models. For the R2, a value closer to 1 indicates a stronger correlation. Prespecified criteria for surrogacy required either R2WLS or R2Copula ≥ 0.80 and neither < 0.7, with lower-bound 95% Confidence Interval (CI) > 0.60. The rank correlation coefficient (ρ) quantified the individual-level surrogacy. Results: Total of 18,886 pts were analyzed, with median age 60, 54% male, 83% stage III, 59% > 12 nodes examined. Median follow-up for survival ranged from 5 to 10 years across trials. Trial level correlation between 3yDFS and OS remained strong (R2WLS ≥0.74; R2Copula ≥ 0.89) and increased as the median follow-up of OS extended longer (see table). Analyses limited to stage III pts and/or trials tested biologics showed consistent results. Conclusions: 3yDFS remains a validated surrogate endpoint for 5yOS in adjuvant trials in CC pts per prespecified criteria. The correlation was strengthened with more than 6 years of follow-up for OS. [Table: see text]

1079 Background: Brain metastases (BM) are a common and fatal complication of breast cancer but survival varies widely based on various prognostic factors (PF). Hence, patient counseling and therapeutic decisions should be individualized. We previously published a prognostic index (Breast GPA) based on cohort A (1985-2007, n = 642), updated it with tumor subtype in cohort B (1993-2010, n = 400) and are now updating it with a larger contemporary cohort (C). Methods: A multi-institutional (19) multi-national (3) retrospective database of 2473 breast cancer patients with BM diagnosed from 1/1/2006-12/31/2017 was created and compared to our prior cohorts. Demographic, clinical, molecular factors, tumor subtype and treatment were correlated with survival. Kaplan-Meier survival estimates were calculated and compared with log-rank tests. Results: The median survival (MS) for cohorts A, B and C improved over time [12, 14 and 16 mo, respectively ( < 0.01)] despite the subtype distribution becoming less favorable: Luminal B (ER/PR/HER2+) decreased from 26% to 21%; HER2 (HER2+/ER/PR-) decreased from 31% to 17%, Luminal A (ER/PR+/HER2-) increased from 20% to 31%; Basal (ER/PR/HER2-) was unchanged at 24%.MS by subtype improved from 21 to 27 mo in Luminal B, 18 to 25 mo in HER2, 10 to 14 mo in Luminal A and 6 to 9 mo in Basal tumors. The number of BM was 1 in 35%, ≤4 in 67% and > 10 in 18%. PF significant for survival were tumor subtype, age, KPS, number of BM and extracranial metastases (ECM) (all < 0.01). Surprisingly, Hispanic women (7%) showed improved survival (p < 0.01). BRCA1 was mutated in 57/533 (11%) and those patients showed a trend (0.16) toward improved survival. Treatment patterns have changed: the use of whole brain radiation therapy decreased from 71% to 67% to 47% in cohorts A, B and C, respectively. Conclusions: Despite the shift to less favorable tumor subtypes, MS has improvedbut varies widely by diagnosis-specific PF. Compared to prior cohorts, number of BM and ECM were identified as new PF. Ethnic, genetic and treatment differences between the eras are apparent. The updated Breast GPA, based on these data, and the correlation between BRCA1 and tumor subtype will be presented.

3501 Background: 6m of oxaliplatin-based treatment is an option as adj chemotherapy for patients with high risk stage II CC (T4, inadequate nodal harvest, poorly differentiated, obstruction, perforation or vascular/perineural invasion). The IDEA collaboration showed shorter treatment duration to be appropriate for most pts with stage III colon cancer. The results of the 4 IDEA studies with stage II pts are presented here. Methods: A prospective, pre-planned pooled analysis of high-risk stage II patients from 4 concurrently conducted randomized phase III trials (SCOT, TOSCA, ACHIEVE-2, HORG) was performed to evaluate non-inferiority (NI) of 3m compared with 6m (ref) of adj FOLFOX/CAPOX (regimen preselected, not randomized). The primary endpoint was disease-free survival (DFS), NI was to be declared if the 2-sided 80% confidence interval (CI) for DFS hazard ratio (HR 3m v 6m) estimated by a stratified Cox model was below 1.2. 542 DFS events were required to provide 80% power to declare NI. NI was also examined within regimen, T4 (Yes v No) and inadequate nodal harvest (Yes v No) as pre-planned subgroups. Results: The primary analysis included 3273 randomised pts of which 1254 had FOLFOX and 2019 had CAPOX. There were 552 events and the median follow-up was 60.2 m. There was significantly less grade 3-5 toxicity with 3m treatment (p < .0001). The 5-year DFS rate was 80.7% and 84.0% for 3m and 6m treatment with an estimated DFS HR of 1.18 (80% CI:1.05-1.31, p for NI = 0.404). For CAPOX the estimated HR was 1.02 (80% CI: 0.88-1.17, p for NI = 0.087) and for FOLFOX the estimated HR was 1.42 (80% CI: 1.19-1.70, p for NI = 0.894). The test for interaction between duration and regimen was not statistically significant (p = .174 adjusted for multiple testing) but was stronger than that for the other subgroups examined. Conclusions: In the overall population non-inferiority for 3m adj treatment in pts with high-risk stage II CC was not shown. As with the stage III population the choice of adj regimen appears important (although this did not reach statistical significance) with a small difference in DFS between 3 and 6 m treatment if CAPOX is used. Clinical trial information: ISRCTN59757862.

During biliary disease, cholangiocytes become activated by various pathological stimuli, including transforming growth factor β (TGF‐β). The result is an epigenetically regulated transcriptional program leading to a pro‐fibrogenic microenvironment, activation of hepatic stellate cells (HSCs), and progression of biliary fibrosis. This study evaluated how TGF‐β signaling intersects with epigenetic machinery in cholangiocytes to support fibrogenic gene transcription. We performed RNA sequencing in cholangiocytes with or without TGF‐β. Ingenuity pathway analysis identified “HSC Activation” as the highly up‐regulated pathway, including overexpression of fibronectin 1 (FN), connective tissue growth factor, and other genes. Bioinformatics identified enhancer of zeste homologue 2 (EZH2) as an epigenetic regulator of the cholangiocyte TGF‐β response. EZH2 overexpression suppressed TGF‐β‐induced FN protein in vitro, suggesting FN as a direct target of EZH2‐based repression. Chromatin immunoprecipitation assays identified an FN promoter element in which EZH2‐mediated tri‐methylation of lysine 27 on histone 3 is diminished by TGF‐β. TGF‐β also caused a 50% reduction in EZH2 protein levels. Proteasome inhibition rescued EZH2 protein and led to reduced FN production. Immunoprecipitation followed by mass spectrometry identified ubiquitin protein ligase E3 component N‐recognin 4 in complex with EZH2, which was validated by western blotting in vitro. Ubiquitin mutation studies suggested K63‐based ubiquitin linkage and chain elongation on EZH2 in response to TGF‐β. A deletion mutant of EZH2, lacking its N‐terminal domain, abrogates both TGF‐β‐stimulated EZH2 degradation and FN release. In vivo, cholangiocyte‐selective knockout of EZH2 exacerbates bile duct ligation–induced fibrosis whereas MDR2‐/‐ mice are protected from fibrosis by the proteasome inhibitor bortezomib. Conclusion: TGF‐β regulates proteasomal degradation of EZH2 through N‐terminal, K63‐linked ubiquitination in cholangiocytes and activates transcription of a fibrogenic gene program that supports biliary fibrosis.

BackgroundThe diagnosis of T‐cell neoplasms is often challenging, due to overlapping features with reactive T‐cells and limitations of currently available T‐cell clonality assays. The description of an antibody specific for one of two mutually exclusive T‐cell receptor (TCR) β‐chain constant regions (TRBC1) provide an opportunity to facilitate the detection of clonal TCRαβ T‐cells based on TRBC‐restriction.MethodsTwenty patients with mature T‐cell neoplasms and 44 patients without evidence of T‐cell neoplasia were studied. Peripheral blood (51), bone marrow (10), and lymph node (3) specimens were evaluated by 9‐color flow cytometry including TRBC1 (CD2/CD3/CD4/CD5/CD7/CD8/CD45/TCRγδ/TRBC1 and/or CD2/CD3/CD4/CD5/CD7/CD8/CD26/CD45/TRBC1). Monophasic TRBC1 expression on any immunophenotypically distinct CD4‐positive or CD8‐positive/TCRγδ‐negative T‐cell subset was considered indicative of clonality.ResultsMonophasic (clonal) TRBC1 expression was identified on immunophenotypically abnormal T‐cells from all 20 patients with T‐cell malignancies (100% sensitivity), including 17 cases with either >97% or <3% TRBC1‐positive events, and three cases with monophasic homogenous TRBC1‐dim expression. All immunophenotypically distinct CD4‐positive and CD8‐positive/TCRγδ‐negative T‐cell subsets from 44 patients without T‐cell malignancies showed the expected mixture of TRBC1‐positive and TRBC‐1‐negative subpopulations (non‐clonal), except for seven patients (16%) with very small CD8‐positive T‐cell subsets exhibiting a monophasic (clonal) pattern.ConclusionInclusion of a single anti‐TRBC1 antibody into a diagnostic T‐cell flow cytometry panel facilitates the rapid identification of T‐cell neoplasms, in addition to small monotypic CD8‐positive subsets of uncertain significance. © 2019 International Clinical Cytometry Society

Abstract The oncolytic reovirus (RV) has demonstrated clinical efficacy and minimal toxicity in a variety of cancers, including multiple myeloma (MM). MM is a malignancy of plasma cells that is considered treatable but incurable because of the 90% relapse rate that is primarily from drug resistance. The systemic nature of MM and the antitumor immunosuppression by its tumor microenvironment presents an ongoing therapeutic challenge. In the present study, we demonstrate that RV synergizes with the standard-of-care MM drug bortezomib (BTZ) and, importantly, enhances its therapeutic potential in therapy-resistant human MM cell lines in vitro. Using the syngeneic Vk*MYC BTZ-resistant immunocompetent transplantable MM murine model, we also demonstrate that mice harboring BTZ-insensitive MM tumors respond to the RV/BTZ combination treatment in terms of decreased tumor burden and improved overall survival (P &lt; .00001). We demonstrate that BTZ augments RV replication in tumor-associated endothelial cells and myeloma cells, leading to enhanced viral delivery and thereby stimulating cytokine release, immune activity, apoptosis, and reduction of the MM-associated immune suppression. We conclude that combined RV/BTZ is an attractive therapeutic strategy with no safety signals for the treatment of MM.