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PURPOSE This randomized, open-label trial compared the efficacy and safety of adjuvant nab-paclitaxel + gemcitabine with those of gemcitabine for resected pancreatic ductal adenocarcinoma (ClinicalTrials.gov identifier: NCT01964430 ). METHODS We assigned 866 treatment-naive patients with pancreatic ductal adenocarcinoma to nab-paclitaxel (125 mg/m2) + gemcitabine (1,000 mg/m2) or gemcitabine alone to one 30-40 infusion on days 1, 8, and 15 of six 28-day cycles. The primary end point was independently assessed disease-free survival (DFS). Additional end points included investigator-assessed DFS, overall survival (OS), and safety. RESULTS Two hundred eighty-seven of 432 patients and 310 of 434 patients completed nab-paclitaxel + gemcitabine and gemcitabine treatment, respectively. At primary data cutoff (December 31, 2018; median follow-up, 38.5 [interquartile range [IQR], 33.8-43 months), the median independently assessed DFS was 19.4 ( nab-paclitaxel + gemcitabine) versus 18.8 months (gemcitabine; hazard ratio [HR], 0.88; 95% CI, 0.729 to 1.063; P = .18). The median investigator-assessed DFS was 16.6 (IQR, 8.4-47.0) and 13.7 (IQR, 8.3-44.1) months, respectively (HR, 0.82; 95% CI, 0.694 to 0.965; P = .02). The median OS (427 events; 68% mature) was 40.5 (IQR, 20.7 to not reached) and 36.2 (IQR, 17.7-53.3) months, respectively (HR, 0.82; 95% CI, 0.680 to 0.996; P = .045). At a 16-month follow-up (cutoff, April 3, 2020; median follow-up, 51.4 months [IQR, 47.0-57.0]), the median OS (511 events; 81% mature) was 41.8 ( nab-paclitaxel + gemcitabine) versus 37.7 months (gemcitabine; HR, 0.82; 95% CI, 0.687 to 0.973; P = .0232). At the 5-year follow-up (cutoff, April 9, 2021; median follow-up, 63.2 months [IQR, 60.1-68.7]), the median OS (555 events; 88% mature) was 41.8 versus 37.7 months, respectively (HR, 0.80; 95% CI, 0.678 to 0.947; P = .0091). Eighty-six percent ( nab-paclitaxel + gemcitabine) and 68% (gemcitabine) of patients experienced grade ≥ 3 treatment-emergent adverse events. Two patients per study arm died of treatment-emergent adverse events. CONCLUSION The primary end point (independently assessed DFS) was not met despite favorable OS seen with nab-paclitaxel + gemcitabine.

Background Randomized studies have shown low compliance to adjuvant chemotherapy in rectal cancer patients receiving preoperative chemotherapy and external beam radiation (CT/EBRT) with total mesorectal excision. We hypothesize that giving neoadjuvant CT before local treatment would improve CT compliance. Methods Between 2010–2017, 180 patients were randomized (2:1) to either Arm A (AA) with FOLFOX x6 cycles prior to high dose rate brachytherapy (HDRBT) and surgery plus adjuvant FOLFOX x6 cycles, or Arm B (AB), with neoadjuvant HDRBT with surgery and adjuvant FOLFOX x12 cycles. The primary endpoint was CT compliance to ≥85% of full-dose CT for the first six cycles. Secondary endpoints were ypT0N0, five-year disease free survival (DFS), local control and overall survival (OS). Results Patients were randomized to either AA (n = 120, median age (MA) 62 years) or AB (n = 60, MA 63 years). 175/180 patients completed HDRBT as planned (97.2%). In AA, two patients expired during CT; three patients post-randomization received short course EBRT because of progression under CT (n = 2, AA) or personal preference (n = 1, AB). ypT0N0 was 31% in AA and 28% in AB (p = 0.7). CT Compliance was 80% in AA and 53% in AB (p = 0.0002). Acute G3/G4 toxicity was 35.8% in AA and 27.6% in AB (p = 0.23). With a median follow-up of 48.5 months (IQR 33–72), the five-year DFS was 72.3% with AA and 68.3% with AB (p = 0.74), the five-year OS 83.8% for AA and 82.2% for AB (p = 0.53), and the five-year local recurrence was 6.3% for AA and 5.8% for AB (p = 0.71). Conclusion We confirmed improved compliance to neoadjuvant CT in this study. Although there is no statistical difference in ypT0N0 rate, local recurrence, and DFS between the two arms, a trend towards favourable oncological outcomes is observed.

Scott Owen,1 Scheryll Alken,2,3 Jad Alshami,1 Marie-Christine Guiot,1,4 Petr Kavan,1 David A Reardon,5 Thierry Muanza,1,4,6 Neil Gibson,7 Karine Pemberton,8 Flavio Solca,9 Agnieszka Cseh10 ,†Frank Saran2,11 1Clinical Research Unit, Montreal Neurological Institute and Hospital, McGill University Health Center, Montreal, Canada; 2Radiation Oncology Unit, Royal Marsden Hospital, London, UK; 3St James’s Hospital, Dublin, Ireland; 4Neuropathology Division, Montreal Neurological Institute and Hospital, McGill University Health Center, Montreal, Canada; 5Center for Neuro-Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; 6Radiation Oncology, Jewish General Hospital, Montreal, Canada; 7Drug Metabolism & Pharmacokinetics, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany; 8Medical Department, Boehringer Ingelheim Ltd., Bracknell, UK; 9Department of Pharmacology, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria; 10Department of Medical Affairs, Boehringer Ingelheim International, Ingelheim am Rhein, Germany; 11Department of Blood and Cancer, Auckland City Hospital, Auckland, New Zealand†Agnieszka Cseh passed away in May 2021Correspondence: Frank Saran, Auckland City Hospital, Cancer and Blood Service, Building 8, 99 Park Road, Grafton, Private Bag 92024, Auckland, 1142, New Zealand, Tel +64 09 623 6046, Email FSaran@adhb.govt.nzAbstract: Glioblastoma is an aggressive form of central nervous system tumor. Recurrence rates following primary therapy are high, and few second-line treatment options provide durable clinical benefit. Aberrations of the epidermal growth factor receptor (EGFR) gene are observed in up to 57% of glioblastoma cases and EGFR overexpression has been identified in approximately 60% of primary glioblastomas. In preclinical studies, afatinib, a second-generation ErbB blocker, inhibited cell proliferation in cells harboring mutations commonly found in glioblastoma. In two previous Phase I/II studies of afatinib plus temozolomide in patients with glioblastoma, limited efficacy was observed; however, there was notable benefit in patients with the EGFR variant III (EGFRvIII) mutation, EGFR amplification, and those with loss of phosphatase and tensin homolog (PTEN). This case series report details treatment histories of three long-term responders from these trials. Next-generation sequencing of tumor samples identified alterations in a number of cancer-related genes, including mutations in, and amplification of, EGFR. Tumor samples from all three patients shared favorable prognostic factors, eg O6-methylguanine-DNA methyl-transferase (MGMT) gene promoter methylation; however, negative prognostic factors were also observed, suggesting that these shared genetic features did not completely account for the favorable responses. The genetic profile of the tumor from Patient 1 showed clear differences from the other two tumors: lack of involvement of EGFR aberrations but with a mutation occurring in PTPN11. Preclinical studies showed that single-agent afatinib and temozolomide both separately inhibit the growth of tumors with a C-terminal EGFR truncation, thus providing further rationale for combining these two agents in the treatment of glioblastomas harboring EGFR aberrations. These findings suggest that afatinib may provide treatment benefit in patients with glioblastomas that harbor ErbB family aberrations and, potentially, other genetic aberrations. Further studies are needed to establish which patients with newly diagnosed/recurrent glioblastomas may potentially benefit from treatment with afatinib.Keywords: next-generation sequencing, long-term response, EGFR, genetic aberrations

Introduction and Background: Salmonella-IL2 (Saltikva) is an attenuated strain of orally administered Salmonella that carries the human gene for IL-2 that colonizes the tumor microenvironment and locally releases IL-2 without any untoward effects. Following significant anti-tumor responses during preclinical study in multiple tumor models; a Phase I trial in humans found a single dose to be not toxic and elevated the Natural Killer T cell populations in patients with advanced gastrointestinal (GI) cancers. Additionally, a Phase I multiple dose trial in companion dogs with metastatic osteosarcoma demonstrated a 22% complete response rate. A Phase II trial was performed studying the addition of Salmonella-IL2 to standard of care chemotherapy for stage 4 metastatic pancreatic cancer. Patients and Methods: A Health Canada and local IRB approved, non-randomized, two-arm study in patients with Stage 4 metastatic adenocarcinoma of the pancreas is currently underway. The goal is to recruit 30 patients per arm; Arm 1: Salmonella-IL2 with FOLFIRINOX and Arm 2: Salmonella-IL2 with Gemcitabine/Abraxane. The primary outcome is overall survival with secondary outcomes of response determined by CT imaging using RECIST 1.1 criteria and biomarker data. Outcomes were compared to patients with stage 4 metastatic pancreatic cancer administered FOLFIRINOX (n=37) or Gemcitabine/Abraxane (n=24) from 4 years prior to starting this trial (2016-2020) at the study site and to historical controls from the published literature. Salmonella-IL2 is orally administered concomitantly with the administration of the prescribed chemotherapy according to arm of enrollment. 109 cfu of attenuated Salmonella-IL2 was administered orally after ingestion of a gastric acid neutralizing agent and followed with 200ml of an isotonic crystalloid fluid. Results: A total of 28 patients have been enrolled into this clinical trial. 20 patients were administered Salmonella-IL2 orally every 2 weeks with FOLFIRINOX; mean age 59.4 (32-73) years; 12(60%) women, and 8 (40%) men. 8 patients were administered Salmonella-IL2 with Gemcitabine/Abraxane every 2/3 weeks; mean age is 68.8 (56-82); 6 (66.7%) women and 3 (33.3%) men. Median survival in the FOLFIRINOX arm was 24 months compared to 11.1 months in published historical controls and 13.1 months site specific controls (n=37) (P Conclusion: Addition of Salmonella-IL2 to FOLFIRINOX for stage 4 metastatic pancreatic cancer results in the near doubling of median survival when compared to historical and site-specific controls receiving FOLFIRNOX only. These findings strongly indicate that a larger pivotal phase 3 multicenter trial is warranted. Citation Format: Petr Kavan, Daniel A. Saltzman, Jule Muegge, Jordan Moradian, Gerald Batist. Addition of Salmonella-IL2 to FOLFIRINOX for metastatic stage 4 pancreatic cancer nearly doubles median survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT035.

Background: BOLD-100 is a first-in-class ruthenium-based anticancer agent in Phase 1b/2a clinical development for the treatment of advanced gastrointestinal (GI) cancers in combination with FOLFOX. BOLD-100 demonstrated synergy in established preclinical models in combination with various anticancer therapies, particularly in resistant cell lines. In the first interim analysis of the phase 1b dose-escalation component of the clinical trial, BOLD-100 plus FOLFOX was well-tolerated in patients (pts) with advanced GI solid cancers. Methods: This is a prospective, Phase 1b dose-escalation (Part A) and Phase 2a dose-expansion (Part B) study of BOLD-100 in combination with FOLFOX for colorectal (CRC), pancreatic (PDAC), gastric (GC) and biliary tract (BTC) cancers. Pts receive BOLD-100 with FOLFOX on day 1 of each 14-day cycle. In Part A, pts were enrolled in a 3+3 design to determine the combination recommended Phase 2 dose (RP2D), with BOLD-100 dose-escalation (420, 500 and 625 mg/m2). Part B comprises 4 cohorts treated at the RP2D of 625 mg/m2 until progressive disease or unacceptable toxicity. The primary objective of Part B is to evaluate the efficacy of BOLD-100 in three clinical endpoints (PFS, OS, and ORR). Bayesian modelling is used to continually reassess these endpoints; the posterior probability of superiority to a historical landmark for each endpoint. Results: As of 31 Dec 2022, 17 pts with advanced metastatic colorectal cancer median age 62 years were treated. Pts received a median of 4 prior systemic therapies, 14 had received prior FOLFOX and 16 (94%) were enrolled with stage IV disease. Median number of cycles completed was 7 (range 1-12). Median PFS was 4.7 [2.9,8.6] months, median OS 9.8 [5.2,22] months, and ORR 13% [3,36] compared to the historical benchmark of 2.0 months, 7.1 months, and 1.6% respectively for similar patients treated with approved standard of care. Two pts achieved a partial response and 11 pts had stable disease for an overall disease control rate of 87% (13/15 [64%,97%]). This compares favorably to the historical control 44%. 16 pts reported 1 or more treatment-emergent adverse events (AEs), most commonly neutrophil count decreased (n=9, 52.9%), fatigue (n=6, 35.3%), pyrexia (n=4, 23.5%), platelet count decreased (n=4, 23.5%) and decreased appetite (n=4, 23.5%). Most of the AEs were grade (G) 1-2. 12 G3 AEs were observed (mostly neutrophil count decreased [8]). Conclusion: BOLD-100 plus FOLFOX is an active and well-tolerated treatment regimen in the heavily pre-treated metastatic CRC trial population. There were no new safety signals. PK and PD data are forthcoming. The preliminary mPFS, mOS, ORR and DCR data in this interim analysis demonstrate significant improvement over the currently available approved therapies. Citation Format: Jennifer Spratlin, Grainne O'Kane, Do-Youn Oh, Sun Young Rha, Elaine McWhirter, Elena Elimova, Petr Kavan, Moon Ki Choi, Dae Won Kim, Rachel Goodwin, J Randolph Hecht, Seung Tae Kim, Dong-Hoe Koo, Khalif Halani, E Russell McAllister, Michelle Jones, Malcolm Snow, Yasmin Lemmerick, Gonzalo Spera, Jim Pankovich. BOLD-100-001 (TRIO039): a phase 1b/2a dose-escalation study of BOLD-100 in combination with FOLFOX chemotherapy in patients with pre-treated advanced colorectal cancer: interim efficacy, safety and tolerability analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT149.

332 Background: Docetaxel-based therapy is currently the most effective neoadjuvant regimen for locally advanced gastroesophageal adenocarcinoma. However, prior trials were primarily designed to target gastric cancer. As survival associated with taxane-based chemotherapy in esophageal adenocarcinoma (EAC) is less well described, we sought to review our experience with docetaxel based therapy as a neoadjuvant approach for EAC. Methods: A single centre retrospective review of a prospectively maintained upper GI cancer surgical database was performed (2008-2021). Patients with EAC undergoing curative intent neoadjuvant therapy with two similar docetaxel-based regimens (DCF - Docetaxel/Cisplatin/5FU or FLOT - 5FU, Leucovorin, Oxaliplatin, and Docetaxel) followed by en-bloc resection were included. Gastric/EGJ type III tumors were excluded. Clinicopathological data and overall survival (OS) were recorded and stratified by chemotherapy type (DCF vs FLOT). Data are presented as median (+/-SD). Mann-Whitney U tests for continuous or Fischer exact test for categorical variables determined significance. Kaplan-Meier curves compared OS. Results: 225 EAC patients were identified: Age 64.2 (±10.3) and tumor location was Esophageal/EGJ I/EGJ II (106/33/86). Clinical stage was cT3-4 in 201/225 (89.3%) and most were cN+ (200/225: 88.9%). There were 121 (53.7%) treated with neoadjuvant DCF whilst 104 (46.3%) received FLOT. All pre-op cycles were completed in 181 (80.4%) and did not differ between DCF and FLOT (81.8% vs 78.8% - NS). Operative procedure included Ivor Lewis in 188 (83.5%), left thoraco-abdominal esophagectomy in 20 (8.8%), and McKeown in 17 (7.5%) and also did not differ between DCF and FLOT. In terms of pathologic outcomes, the median lymph node yield was 35 (±16) of which 3.6±5.8 were positive). There was no difference when comparing between regimens. There were 134 (59.6%) patients ypN1-3 (DCF=76(62.8%) vs FLOT=58(55.8%)- NS). An R0 resection was achieved in 210 (93%) patients (DCF=92.6% vs FLOT=94.2%- NS). Complete pathological response (no residual cancer) was found in 21 patients (9.3%) (DCF=14(11.6%) vs FLOT=7(6.7%) – NS). At follow up of 41(±36) months (DCF= 52±41 vs FLOT=27±23 - p

183 Background: In response to energetic stress, colorectal cancer cells secrete creatine kinase brain-type (CKB). CKB converts creatine and ATP from the extracellular matrix to PC, which is imported intracellularly to sustain survival and metastatic spread. In addition, PC modulates immune cell functions and may play a role in mediating responses to immune checkpoint inhibition. CO.26 was a phase II trial (NCT02870920) that randomized patients (pts) with refractory mCRC to durvalumab plus tremelimumab (D+T) versus best supportive care (BSC). In an exploratory, post-hoc analysis, we investigated the role of plasma PC as a predictive biomarker for response to D+T. Methods: PC concentrations were determined from pre-treatment blood samples with HPLC-tandem mass spectrometer. A minimum p-value approach was used to select an optimum cut-off value which dichotomized patients into low (< 95.6 ng/ml) versus high (≥ 95.6 ng/ml) groups predictive for benefit. Cox proportional hazard models were used to analyze predictive impacts of PC on progression free survival (PFS) and overall survival (OS). Results: Of 180 pts enrolled, pre-treatment blood samples were available for 162 pts (N =115 for D+T; 47 BSC). Pre-treatment PC was low in 15% (N=24) and high in 85% (N=138). There were no differences in baseline characteristics between pts included in this analysis and the total study pts, or PC low and high pts. D+T improved OS significantly in PC low pts (median OS 4.7 months vs 2.3 months; Hazard Ratio (HR) 0.32, 95% confidence interval (CI): 0.11 – 0.95, p = 0.03). There was no improvement in PC high pts with D+T (median OS 6.8 vs 5.2 months; HR 0.80, 95% CI: 0.55 – 1.17, p = 0.24. Interaction p < 0.0001). Plasma PC values had no impact on PFS and rates of disease control. Conclusions: Pts with low plasma PC derived more benefit from immune checkpoint inhibition with D+T in pts with refractory mCRC. Further prospective validation studies are needed. Predictive analysis for OS with pre-treatment PC levels dichotomized by minimum p approach. [Table: see text]

Background: To date, the role of adjuvant systemic therapy in stages ii and iii colon cancer remains a topic of interest and debate. The objective of the present review was to assess the most recent data, specifically addressing methods of risk stratification, duration of therapy, and future directions. Methods: PubMed and medline were searched for literature pertinent to adjuvant chemotherapy in either stage ii or stage iii colorectal cancer. Summary: Locoregional disease, histopathology, age, laterality, and a number of other biologic and molecular markers appear to have a role in disease risk stratification. The duration of adjuvant therapy for stage iii disease can vary based on risk factors, but use of adjuvant therapy and duration of therapy in stage ii disease remain controversial. Future directions should include genomic assays and improved study design to provide concrete evidence about the duration of adjuvant folfox or capox and about other types of chemotherapy and immunotherapy.

PURPOSE KEYNOTE-164 (NCT02460198) evaluated the antitumor activity of pembrolizumab in previously treated, metastatic, microsatellite instability–high/mismatch repair–deficient (MSI-H/dMMR) colorectal cancer (CRC). METHODS This phase II open-label study involved 128 centers worldwide. Eligible patients were age ≥ 18 years and had metastatic MSI-H/dMMR CRC treated with ≥ 2 prior lines of standard therapy, including fluoropyrimidine, oxaliplatin, and irinotecan with or without anti–vascular endothelial growth factor/epidermal growth factor receptor monoclonal antibody (cohort A) or ≥ 1 prior line of therapy (cohort B). MSI-H/dMMR status was assessed locally. Patients received pembrolizumab 200 mg every 3 weeks for up to 2 years until progression, unacceptable toxicity, or withdrawal. The primary end point was objective response rate by RECIST version 1.1 by independent central review. Secondary end points were duration of response, progression-free survival (PFS), overall survival, safety, and tolerability. RESULTS A total of 124 patients with MSI-H/dMMR CRC (61 in cohort A, 63 in cohort B) enrolled. At data cutoff, median follow-up was 31.3 months (range, 0.2-35.6 months) for cohort A and 24.2 months (range, 0.1-27.1 months) for cohort B. Objective response rate was 33% (95% CI, 21% to 46%) and 33% (95% CI, 22% to 46%), respectively, with median duration of response not reached in either cohort. Median PFS was 2.3 months (95% CI, 2.1 to 8.1 months) and 4.1 months (95% CI, 2.1 to 18.9 months). Median overall survival was 31.4 months (95% CI, 21.4 months to not reached) and not reached (95% CI, 19.2 months to not reached). Treatment-related grade 3-4 adverse events occurred in 10 patients (16%) in cohort A and 8 (13%) in cohort B, with the most common occurring in ≥ 2 patients being pancreatitis, fatigue, increased alanine aminotransferase, and increased lipase (2 patients each; 3%) in cohort A. CONCLUSION Pembrolizumab is effective with a manageable safety profile in patients with MSI-H/dMMR CRC.

Young adult oncology has gained momentum in recognizing the unique medical and psychosocial needs of the population of adolescents and young adults with cancer (AYAC). However, many of their psychosocial needs remain unmet and we are yet to identify how clinical or research programs can be tailored to meet these needs. The aim of the study was to evaluate the impact of a cognitive-behavioral intervention adapted to meet the psychosocial needs and issues of AYAC and delivered either through Skype or face-to-face sessions against a control condition.A total of 113 AYAC aged between 18 and 39 years were randomly assigned to a brief three-session intervention or control/care-as-usual group. They were then assessed at three time points of baseline (time 1), post (time 2), and 3-month postintervention (time 3) using self-report questionnaires targeting overall outcomes of mood/emotional well-being and health-related quality of life (HRQOL) and specific outcomes of illness-related self-efficacy and family/social and sexual relationship well-being.Significant between-group differences were obtained from time 1 to time 2 on outcomes of social/family and sexual relationship well-being, whereas groups did not differ from time 2 to time 3. Within-group results from time 1 to time 2 showed significant improvements in sexual esteem for both groups, whereas only AYAC of the intervention group significantly improved on outcomes of anxiety, overall mood/emotional well-being and HRQOL. In addition, improvements in self-efficacy were obtained only for the intervention group from time 2 to time 3.When compared with a control/care-as-usual condition, the intervention had a positive impact on psychological and relationship well-being. Results suggested that the intervention was beneficial and clinically relevant to the population of AYAC.

Background Therapeutic resistance is the main cause of death in metastatic colorectal cancer. To investigate genomic plasticity, most specifically of metastatic lesions, associated with response to first‐line systemic therapy, we collected longitudinal liver metastatic samples and characterized the copy number aberration (CNA) landscape and its effect on the transcriptome. Methods Liver metastatic biopsies were collected prior to treatment (pre, n = 97) and when clinical imaging demonstrated therapeutic resistance (post, n = 43). CNAs were inferred from whole exome sequencing and were correlated with both the status of the lesion and overall patient progression‐free survival (PFS). We used RNA sequencing data from the same sample set to validate aberrations as well as independent datasets to prioritize candidate genes. Results We identified a significantly increased frequency gain of a unique CN, in liver metastatic lesions after first‐line treatment, on chr18p11.32 harboring 10 genes, including TYMS, which has not been reported in primary tumors (GISTIC method and test of equal proportions, FDR‐adjusted p = 0.0023). CNA lesion profiles exhibiting different treatment responses were compared and we detected focal genomic divergences in post‐treatment resistant lesions but not in responder lesions (two‐tailed Fisher's Exact test, unadjusted p ≤ 0.005). The importance of examining metastatic lesions is highlighted by the fact that 15 out of 18 independently validated CNA regions found to be associated with PFS in this study were only identified in the metastatic lesions and not in the primary tumors. Conclusion This investigation of genomic‐phenotype associations in a large colorectal cancer liver metastases cohort identified novel molecular features associated with treatment response, supporting the clinical importance of collecting metastatic samples in a defined clinical setting., Graphical Abstract and Graphical Headlights Liver metastatic lesions from colorectal cancer patients were collected before and after first‐line standard chemotherapy and comprehensively profiled with the objective to assess the genomic impact of systemic therapy and investigate association with response and survival. This study allowed identification of novel CNAs having an impact on the transcriptome with a potential prognostic value in patients with colorectal cancer.

PurposeAdjuvant chemotherapy within 56 or 84 days following curative resection is globally accepted as the standard of care for stage III colon cancer as it has been associated with improved overall survival. Initiation of adjuvant chemotherapy within this time frame is therefore recommended by clinical practice guidelines, including the European Society for Medical Oncology. The objective of this study was to evaluate adherence to these clinical practice guidelines for patients with stage III colon cancer across the Rossy Cancer Network (RCN); a partnership of McGill University’s Faculty of Medicine, McGill University Health Centre, Jewish General Hospital and St Mary’s Hospital Center.Patients and methods187 patients who had been diagnosed with stage III colon cancer and received adjuvant chemotherapy within the RCN partner hospitals from 2012 to 2015 were included. Patient and treatment information was retrospectively determined by chart review. Χ2 and Wilcoxon rank-sum tests were used to measure associations and a multivariate Cox regression model was used to determine risk factors contributing to delays in administration of adjuvant chemotherapy.ResultsThe median turnaround time between surgery and adjuvant chemotherapy was 69 days. Importantly, only 27% of patients met the 56-day target, and 71% met the 84-day target. Increasing age, having more than one surgical complication and being diagnosed between 2013–2014 and 2014–2015 reduced the likelihood that patients met these targets. Furthermore, delays were observed at most intervals from surgery to first adjuvant chemotherapy treatment.ConclusionOur study found that within these academic hospital settings, 27% of patients met the 56-day target, and 71% met the 84-day target. Delays were associated with hospital, surgeon and patient-related factors. Initiatives in quality improvement are needed in order to improve adherence to recommended treatment guidelines for prompt administration of adjuvant chemotherapy for stage III colon cancer.

Background: We explored image-guided adaptive endorectal brachytherapy patients electing non-operative management for rectal cancer. We present the first pre-planned interim analysis. Methods: In this open-label phase II–III randomized study, patients with operable cT2-3ab N0 M0 rectal cancer received 45 Gy in 25 fractions of pelvic external beam radiotherapy (EBRT) with 5-FU/Capecitabine. They were randomized 1:1 to receive either an EBRT boost of 9 Gy in 5 fractions (Arm A) or three weekly adaptive brachytherapy (IGAEBT) boosts totaling 30 Gy (Arm B). Patient characteristics and toxicity are presented using descriptive analyses; TME-free survival between arms with the intention to treat the population is explored using the Kaplan–Meier method. Results: A total of 40 patients were in this analysis. Baseline characteristics were balanced; acute toxicities were similar. Complete clinical response (cCR) was 50% (n = 10/20) in Arm A and 90% in Arm B (n = 18/20). Median follow-up was 1.3 years; 2-year TME-free survival was 38.6% (95% CI: 16.5–60.6%) in the EBRT arm and 76.6% (95% CI: 56.1–97.1%) in the IGAEBT arm. Conclusions: Radiation intensification with IGAEBT is feasible. This interim analysis suggests an improvement in TME-free survival when comparing IGAEBT with EBRT, pending confirmation upon completion of this trial.

3521 Background: Response to antiPD-1 monotherapy is poor in patients (pts) with advanced microsatellite stable (MSS)/mismatch-repair proficient (pMMR) CRC. Combination of chemotherapy with antiPD-1 pembro may potentiate the antitumor immune response and provide greater antitumor activity than either agent alone. Combination of pembro and mFOLFOX7 or FOLFIRI in the ongoing phase 1b multicohort KEYNOTE-651 (NCT03374254) study in metastatic MSS/pMMR CRC showed antitumor activity. We present results with approximately 20 mo of additional follow-up. Methods: Pts had metastatic MSS/pMMR CRC and were previously untreated (cohort B) or received 1 prior line including a fluoropyrimidine + oxaliplatin (cohort D). Pts received pembro 200 mg Q3W + mFOLFOX7 Q2W (cohort B) or pembro 200 mg Q3W + FOLFIRI Q2W (cohort D). Primary end points were safety (DLT) and RP2D. Secondary end point was ORR per RECIST v1.1 by investigator review. DOR, DCR, and PFS per RECIST v1.1, and OS were exploratory end points. Results: Median study follow-up (range) at data cutoff (Oct 15, 2021) was 30.2 mo (25.0-43.6) for cohort B (n = 31) and 33.5 mo (25.2-43.2) for cohort D (n = 32). Treatment was discontinued in 29 pts (94%) in cohort B and 28 pts (88%) in cohort D, mostly because of PD (61% and 66%, respectively). At prior analysis (Feb 10, 2020), RP2D was confirmed as the starting dose in both cohorts; no new DLT had occurred. In cohort B, gr 3/4 TRAEs occurred in 18 pts (58%), most commonly neutropenia and decreased neutrophil count (both n = 5; 16%); 19 pts (61%) discontinued drug because of a TRAE. In cohort D, gr 3/4 TRAEs occurred in 17 pts (53%), most commonly, neutropenia (n = 7; 22%), diarrhea and fatigue (both n = 4; 13%); 3 pts (9%) discontinued drug because of a TRAE. There were no gr 5 TRAEs in either cohort. Efficacy by cohort and KRAS mutation status are below (Table). PD-L1 data and DNA/RNA-based biomarker data including GEP, consensus signatures, TMB, and LoF mutations will be included in the presentation. Conclusions: After 2.5 y of follow-up, the combination of pembro with either mFOLFOX7 or FOLFIRI continued to demonstrate a manageable safety profile with no new safety signals. Efficacy data from these single-arm cohorts appear comparable to historical data for current SOC. Clinical trial information: NCT03374254. [Table: see text]

3573 Background: Response to antiPD-1 monotherapy is poor in microsatellite stable (MSS)/mismatch-repair proficient (pMMR) mCRC; the combination of antiPD-1 pembro + anti-MEK bini, with or without chemo, may improve upon this limited response. KEYNOTE-651 (NCT03374254) is an open-label phase 1b multicenter trial of pembro + bini (cohort A) or pembro + bini + chemo (mFOLFOX7 in cohort C, FOLFIRI in cohort E) in MSS/pMMR mCRC. Preliminary results from the dose-finding phase at 2 dose levels (DL) of bini are presented. Methods: Patients (pts) had MSS/pMMR mCRC and must have been previously treated with fluoropyrimidine, irinotecan, and oxaliplatin in cohort A, or with fluoropyrimidine + oxaliplatin-based regimen in cohort E; pts were previously untreated in cohort C. Pts received pembro 200 mg Q3W + bini 30 mg BID (cohort A, DL1), pembro 200 mg Q3W+ bini 30 mg BID + mFOLFOX7 Q2W (cohort C, DL1) or pembro 200 mg Q3W + bini 30 mg BID + FOLFIRI Q2W (cohort E, DL1). Bini dose escalation to 45 mg BID (DL2) was planned in cohorts A, C, and E, with a target dose-limiting toxicity (DLT) of 30%. Primary end point was safety (DLT). Secondary end point was ORR. DCR, PFS, and OS were exploratory. ORR, DCR, and PFS were assessed by investigator per RECIST v1.1. Results: Median study follow-up at data cutoff (Oct 15, 2021) was 36 mo (range, 32-43) for cohort A, 17 mo (2-24) for cohort C, and 11 mo (2-25) for cohort E. In cohort A, 1/6 pts (17%) had DLT at DL1; no DLT occurred in 14 pts (0%) at DL2. In cohort A, gr 3/4 TRAEs occurred in 3/6 pts (50%) at DL1 and 8/14 pts (57%) at DL2. In cohort C, 3/9 evaluable pts (33%) had DLT at DL1; thus, bini dose was not escalated to DL2. In cohort C, gr 3/4 TRAEs occurred in 9/11 total pts (82%). In cohort E, 1/5 evaluable pts (20%) had DLT at DL1 and 5/10 evaluable pts (50%) had DLT at DL2. Enrollment was stopped in cohort E, DL2 and bini dose was de-escalated to DL1; 2/4 additional pts (50%) had DLT at DL1 (total 3/9 pts [33%] had DLT in cohort E, DL1). In cohort E, gr 3/4 TRAEs occurred in 5/9 pts (56%) at DL1 and 10/11 total pts (91%) at DL2. No gr 5 TRAEs occurred in any cohort. ORR was 0% in cohort A; limited efficacy was seen in cohorts C and E (Table). Conclusions: Bini could be safely combined with pembro in cohort A. However, with bini + pembro + chemo, the 45-mg dose of bini was not well tolerated and required dose reduction to 30 mg. Addition of bini to pembro + chemo did not improve efficacy; therefore, enrollment was prematurely closed in cohorts C and E. Efficacy by KRAS mutation status will be shown. Clinical trial information: NCT03374254. [Table: see text]

3600 Background: Immune checkpoint blockade has limited activity in microsatellite-stable (MSS) or mis-match repair proficient (pMMR) CRC. Recent findings suggest that immunotherapy efficacy may be modulated by the presence of liver metastases. We conducted a retrospective analysis of the Canadian Cancer Trials Group (CCTG) CO.26 study to investigate the relationship between the presence of liver metastases and activity of immune checkpoint blockade. Methods: The CCTG CO.26 study was a randomized phase II study (NCT02870920). Pts with treatment refractory CRC were randomized to durvalumab, tremelimumab and best supportive care (BSC) or BSC alone in a 2:1 fashion. Treatment consisted of durvalumab (1500 mg) q 28 days and tremelimumab (75 mg) q 28 days for the first 4 cycles. The primary endpoint was overall survival (OS) and a two-sided p-value

Patients with cancer are at high risk of venous thromboembolic events, and this risk can be further increased in patients with certain cancer types and by cancer treatments. Guidelines on the prevention of cancer-associated thrombosis (CAT) recommend thromboprophylaxis for hospitalised patients; however, this is not routinely recommended for ambulatory patients receiving chemotherapy and is limited to specified high-risk patients. Identification of the ambulatory patients at risk of CAT who would most benefit from anticoagulant therapy is therefore critical to reduce the incidence of this complication. For patients receiving thromboprophylaxis for CAT, treatment options include low molecular weight heparin, acetylsalicylic acid, warfarin or direct oral anticoagulants (apixaban or rivaroxaban), dependent on the cancer type and cancer treatment regimen. This review discusses emerging clinical trial data and their potential clinical impact.

Lenvatinib is an oral multikinase inhibitor indicated for the first-line treatment of unresectable hepatocellular carcinoma (uHCC). In the Phase III REFLECT trial, lenvatinib was noninferior in the primary endpoint of overall survival versus sorafenib, the only systemic therapy funded in Canada prior to the introduction of lenvatinib. Lenvatinib also demonstrated statistically significant improvement compared to sorafenib in secondary endpoint progression-free survival, time to progression, and objective response rate. The aim of this analysis was to estimate the cost-effectiveness of lenvatinib versus sorafenib for the first-line treatment of patients with uHCC from a Canadian perspective. A cost-utility analysis was conducted using partitioned survival modelling, with health states representing progression-free disease, progressed disease, and death. Health effects were measured using quality-adjusted life years (QALYs), and costs were represented in Canadian dollars. Clinical inputs were derived from the REFLECT trial, with outcomes extrapolated using parametric survival models. EQ-5D data collected in REFLECT were used to determine health state utility values, and estimates of resource use came from a survey of clinicians. The model predicted incremental costs of-$5,021 and incremental QALYs of 0.17, making lenvatinib dominant over sorafenib. The model demonstrates lenvatinib to be a cost-effective use of resources versus sorafenib in Canada for the treatment of uHCC. Overall costs are lower compared with sorafenib, while health benefits are greater, with modelled progression-free and overall survival extended by 4.1 and 2.6 months in the lenvatinib arm, respectively.

TPS638 Background: Prospective studies of the benefit of neoadjuvant chemotherapy in resectable pancreatic adenocarcinoma (PDAC) have been reported. The ideal peri-operative regimen is yet to be determined. Adjuvant FOLFIRINOX (mFFX) in resected PDAC has been proven to improve overall survival (OS) relative to adjuvant gemcitabine. An accepted perioperative approach involves delivering the majority of chemotherapy (6-8 cycles) in the pre-operative setting, while the remainder (of 12 cycles) is administered post-operatively. This pre-operative treatment period may allow for chemosensitivity assessment, and better patient selection for surgery, thereby improving R0 resection rates and reducing the frequency of early post-operative recurrence. Data from the COMPASS trial (NCT02750657) has shown that shown that low levels of the transcription factor GATA6 expression is a putative surrogate for the RNA Moffit signature and predictive of a chemoresistant phenotype in advanced PDAC. NeoPancONE will evaluate clinical outcomes and molecular biomarkers including GATA6 and radiomic biomarkers in pts with resectable PDAC treated with perioperative mFFX. Methods: NeoPancONE is a Phase 2, open-label, single arm study in pts with resectable PDAC. Tissue and serum are collected for biomarker testing, including GATA6 by FISH and IHC (1) with expression levels measured by RNAseq, and longitudinal ctDNA analysis. Pts with histologically confirmed, resectable PDAC and ECOG PS 0-1 will be recruited over 2.5 years. Resectability will be determined by central review as per NCCN guidelines. The primary objective is to evaluate disease-free survival in resectable PDAC treated with peri-operative mFFX according to baseline tumor GATA6 expression level. The ratio of GATA6-high to low is expected to be approximately 4:1[1]. Assuming 1-year disease-free survival of 65% in the GATA6-high, compared to 34% in the GATA6-low cohort, this corresponds to a hazard ratio of 2.5. With 80% power and a 5% 2-sided significance level, a total of 84 patients will be enrolled with 67 events expected in the GATA6 high cohort and 17 in GATA6 low. Participants will receive up to 6 cycles of neoadjuvant mFFX. After neoadjuvant chemotherapy, definitive surgical resection will proceed as deemed appropriate by a hepatobiliary surgeon. Post-operatively, pts will receive up to 6 cycles of adjuvant chemotherapy. Secondary objectives include determination of overall response rate, incidence of R0 resection, OS, Moffit gene expression profiling (RNAseq), ctDNA, and radiomic signatures to predict outcomes. Enrolment for NeoPancONE began in October 2020 and is being conducted at 8 sites across Canada. To date, 23 pts have been recruited. The study duration will be five years. Reference: O’Kane G M et al. Clin Can Res Sep 2020. Clinical trial information: NCT04472910.

Background The diagnosis of breast cancer in young women (aged 18-45 years) has been increasing. Women are commonly left coping with treatment-related disabilities of the upper limb that can persist for > 2 years postoperatively. Patients and Methods A total of 59 young breast cancer patients (29 in the intervention group and 30 in the control group) participated in a pilot prospective randomized controlled trial to determine whether a 12-week postradiation exercise program would improve long-term arm mobility, pain, and handgrip strength. During an 18-month period, range of motion, handgrip strength, and pain with shoulder movements were evaluated at 6 points. Results Although the differences were not statistically significant, external rotation and horizontal abduction of the shoulder improved in the intervention group immediately after the exercise intervention (3 months) and showed a trend toward less pain on movement. However, at 18 months after radiation the control and intervention groups both retained a residual loss of range and persistent pain with movement. Radiation to the axilla and/or chest wall yielded long-term (18 months) limitations in flexion and horizontal abduction compared with hypofractionation, which resulted in greater flexion and external rotation at 18 months. The median grip strength of the study participants corresponded to the 10th percentile of healthy aged-matched white women. Conclusion The exercise intervention timed shortly after radiation improved short-term shoulder mobility and pain; however, these gains were not sustained at 18 months after radiation.

Background: Selection and sequencing of treatment regimens for individual patients with metastatic colorectal cancer (mcrc) is driven by maintaining reasonable quality of life and extending survival, as well as by access to and cost of therapies. The objectives of the present study were to describe, for patients with mcrc, attrition across lines of systemic therapy, patterns of therapy and their timing, and KRAS status. Methods: A retrospective chart review at 6 Canadian academic centres included sequential patients who were diagnosed with mcrc from 1 January 2009 onward and who initiated first-line systemic treatment for mcrc between 1 January and 31 December 2009. Death was included as a competing risk in the analysis. Results: The analysis included 200 patients who started first-line therapy. The proportions of patients who started second-, third-, and fourth-line systemic therapy were 70%, 30%, and 15% respectively. Chemotherapy plus bevacizumab was the most common first-line combination (66%). The most common first-line regimen was folfiri plus bevacizumab. KRAS testing was performed in 103 patients (52%), and 38 of 68 patients (56%, 19% overall) with confirmed KRAS wild-type tumours received an epidermal growth factor receptor inhibitor (egfri), which was more common in later lines. Most KRAS testing occurred after initiation of second-line therapy. Conclusions: In the modern treatment era, a high proportion of patients receive at least two lines of therapy for mcrc, but only 19% receive egfri therapy. Earlier KRAS testing and therapy with an egfri might allow a greater proportion of patients to access all 5 active treatment agents.

Background According to the IDEA trial, 6-month adjuvant chemotherapy should remain the treatment standard in stage III T4 or N2 colon cancer. The relatively poor survival in this high-risk subgroup—a 3-year disease-free survival (DFS) rate of 65%—and the potential synergistic efficacy of 5-fluorouracil (5-FU), oxaliplatin, and irinotecan suggest that FOLFIRINOX may be a regimen of particular interest in this setting. Patients and Methods This multicenter international phase 3 trial (ClinicalTrials.gov NCT02967289 ) being conducted in 49 centers in France and Canada plans to randomize (1:1; minimization method) 640 patients aged 18 to 70 years with Eastern Cooperative Oncology Group performance status ≤ 1. Randomization occurs within 42 days (with treatment initiated within 56 days) after curative-intent R0 surgical resection of a pT4N1 or pT1-4N2 colon adenocarcinoma. Patients will be randomized to receive adjuvant modified FOLFIRINOX (oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, irinotecan 180 mg/m2, and 5-FU 2.4 g/m2 over 46 hours) or modified FOLFOX6 (oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, 5-FU bolus 400 mg/m2, then 2.4 g/m2 over 46 hours) every 2 weeks for 24 weeks (12 cycles). Patients will be followed for 5 years after the end of adjuvant chemotherapy. A gain of 9% in 3-year DFS (primary end point) is expected (74% in the experimental arm vs. 65% in the control arm; α, 5% [2-sided log-rank test]; 1-β, 80%). Secondary end points of this study include 2-year DFS, overall survival, and toxicity.

e15589 Background: Worldwide treatment for 1st line (1LTx) mCRC included doublet or triple chemotherapy with or without bTAs. In Quebec, the anti-EGFR therapy (panitumumab or cetuximab) was only recently approved in this setting for patients RAS WT, Bevacizumab (B) not eligible. In this study we evaluated the rational and outcomes using bTAs. Methods: Retrospective study assessing mCRC pts treated with or without bTAs at any time throughout the course of therapy at the Jewish General Hospital between 2010-2018. Pts were divided in 3 groups according to their 1LTx for analysis: Chemotherapy alone (1LChA), Chemotherapy plus B (1LChB), and anti-EGFR with or without chemotherapy (1LaEGFR). The primary objective was to assess the rational of bTAs prescription based in 1LTx selection. Secondary objectives included safety, PFS and OS. Results: Among a total of 463 pts with mCRC; 196 pts (42.3%) received 1LChA, 246 pts (53.2%) 1LChB, and 21 pts (4.5%) 1LaEGFR respectively. 1LChA group, 51% omitted bTAs for physician-patient preferences, 96 pts (49%) had contraindications for B, and 79 pts (40.3%) were potentially candidates for aEGFR, but did not receive it. 152/196 (77.5%) pts continued to 2LTx and 34.8% received bTAs. As for the 3LTx, 78/196 (40%) received a treatment, 48.7% received bTAs. The most common grade 3-4 adverse events (AEs) were hypertension and bowel perforation in B, gastrointestinal (GI) symptoms and skin reaction (SR) in aEGFR. 1LChB group, 31 pts (12.6%) presented AEs related to B. 191/246 pts (77.6%) continued to 2LTx with 48 pts (25%) receiving ChB despite progression in 1LTx on this bTA and 19 pts (10%) receiving aEGFR. The most common AEs reported in 2LTx were GI symptoms and neuropathy. In 3LTx, 54/91pts (59.3%) received aEGFR therapy and 8 pts (14.8%) had SR AEs. 46 pts (18.6%) continued to 4LTx, 13/46 pts (28.2%) received aEGFR. 1LaEGFR group, the most common AEs were SR and GI symptoms. 11/21 pts (52.3%) continued to 2LTx; 5 pts (45.4%) switching bTA class and receiving ChB. 81% pts started treatment between 2017-2018 and had at least two contraindication criteria for. The median PFS for the 1LChA and 1LChB groups were 10 and 11.5 months, respectively, and were not statistically significant (p=0.22). The OS with 1LChA and 1LChB was 33.26 vs. 27.80 months (p=0.27). The PFS and OS between 1LChA and 1LaEGFR were 10 vs 11 months (p= 0.27) and 33.26 vs. 35.07 months (p=0.13). Conclusions: The outcome and tolerability of bTAs in mCRC appear similar in our institution and randomised trials. We were not able to detect any significant difference among the three groups of comparison. The 1LaEGFR available data in this subset of patients are limited. Our data highlights the importance of optimal therapeutic sequencing to prolong OS. Dedicated studies are needed in order to determine the best bTAs therapeutic strategy in mCRC.

4135 Background: PA.7 evaluated whether combining PD-L1 and CTLA-4 inhibition with GEM and Nab-P increases efficacy. A previous analysis of the PA.7 data demonstrated high plasma based TMB (≥9 mut/Mb) was associated with improved OS in the Gem, Nab-P, D+T arm. DNA repair pathway aberrations beyond mismatch repair have been associated with potential immune sensitivity. We assessed the predictive value of germline ATM mutations in the PA.7 trial. Methods: This randomized phase II study (ClinicalTrials.gov NCT02879318) assessed the efficacy and safety of GEM, Nab-P, D, and T (arm A) vs. GEM and Nab-P (arm B) in patients (pts) with mPDAC (n = 180). The primary endpoint was overall survival (OS). Pre-treatment plasma was sequenced with the Predicine ATLAS next generation assay (600 gene, 2.4 Mb panel). 2-sided alpha set at 0.1. Results: 180 pts were randomized (119 to arm A and 61 to arm B) There was no significant difference in OS (9.8 months in arm A vs. 8.8 months in arm B, p-value 0.72) or PFS (5.5 months and 5.4 months respectively, HR 0.98, p-value 0.91). Plasma analysis was performed on 174/180 pts with available samples. 16/174 (9.2%) pts had germline ATM mutations, 12 in arm A and 4 in arm B. GEM, Nab-P, D+T was associated with improved OS in patients with ATM mutations (HR 0.10, 90% CI 0.03-0.37; median OS 13.9 months vs. 4.9 months) while no activity was seen in pts with ATM Wild Type (HR 0.99, 90% CI 0.73-1.33; median OS 9.79 months vs. 10.2 months); interaction p = 0.014. Germline ATM mutation status was independent of plasma TMB levels (Wilcoxon p = 0.76). Conclusions: Germline ATM mutation appeared predictive of benefit from the addition of dual immune checkpoint inhibitors (D and T) to Gem and Nab-P, with a significant interaction p-value. In addition to previous data from this trial regarding the predictive value of high plasma TMB (≥9 mut/Mb), this data further supports that there may be independent subgroups of PDAC, beyond MSI-H, that may benefit from immunotherapy, and trials evaluating immunotherapy in subgroups of PDAC with these profiles are warranted. Clinical trial information: NCT02879318.

411 Background: PA.7 evaluated whether combining PD-L1 and CTLA-4 inhibition with GEM and Nab-P increases efficacy as first line therapy in mPDAC. High TMB is associated with immunotherapy sensitivity, with a threshold of ≥10 mut/Mb receiving FDA accelerated approved for pembrolizumab in a tissue agnostic setting. We assessed the predictive value of plasma TMB in the PA.7 trial. Methods: This randomized phase II study (ClinicalTrials.gov NCT02879318) assessed the efficacy and safety of GEM, Nab-P, D, and T (arm A) vs. GEM and Nab-P (arm B) in patients (pts) with mPDAC (n = 180). The primary endpoint was overall survival (OS). Pre-treatment plasma was sequenced with the CLIA-certified PredicineATLAS cfDNA next generation assay (600 genes, 2.4 Mb panel). A pre-specified cut point of 5 mut/MB was selected based on distribution of TMB in the trial. 2-sided alpha set at 0.1. Results: 180 pts were randomized (119 to arm A and 61 to arm B). There was no significant difference in OS (9.8 months in arm A vs. 8.8 months in arm B, p-value 0.72) or PFS (5.5 months and 5.4 months respectively, HR 0.98, p-value 0.91). Plasma TMB analysis was performed on 174/180 pts with available samples, and tumor derived variants were detected in 173/174 pts (99.4%). 172 pts were microsatellite stable and 1 pt was microsatellite high (MSI-H) (plasma TMB 52.9 muts/Mb). Using the pre-specified cut-point of 5 mut/Mb there was no significant predictive value from plasma TMB (interaction p = 0.91). Using a minimum p-value approach, a cut-point of 9 mut/MB appeared predictive (p-interaction = 0.064; significant at pre-specified p = 0.1). 8/174 (4.6%) pts had a plasma TMB ≥9 mut/Mb (5/115 (4.4%) in arm A and 3/59 (5%) in arm B). GEM, Nab-P, D+T was associated with improved OS in patients with plasma TMB ≥9 mut/Mb (HR 0.30, 90% CI 0.06-1.37) while no activity was seen in pts with < 9 mut/Mb, (HR 0.97, 90% CI 0.73-1.29). TMB cut-point analysis revealed a clear trend for a decreasing HR favoring the GEM, Nab-P, D and T arm above the selected cut point, with no benefit in the low TMB group. Conclusions: Plasma TMB analysis was successful in over 99% of pts with available samples. Plasma TMB ≥9 mut/Mb was predictive of benefit from the addition of dual immune checkpoint inhibitors (D and T) to Gem and Nab-P, with a significant interaction p-value. While only present in a subgroup of pts (4.6%), this data defines a group beyond MSI-H PDAC that may benefit from immunotherapy. The optimal cut-point for high TMB in this setting requires validation. A clinical trial specifically assessing the role of chemotherapy combined with immune checkpoint inhibition in high TMB mPDAC is warranted. Clinical trial information: NCT02879318.

TPS145 Background: Although most cancers are initially susceptible to existing anticancer therapies, over time cancer cells develop resistance. BOLD-100 is a first-in-class therapy that targets the GRP78 pathway, a major regulator of cellular stress and resistance. This therapy suppresses drug resistance, survival and proliferation by restraining stress-induced upregulation of GRP78 in tumor cells, leading to inhibition of the cell survival response. BOLD-100 successfully completed a Phase 1 monotherapy trial, with a manageable safety profile; it has demonstrated synergy in established preclinical models in combination with a wide variety of anticancer therapies and shown to restore sensitivity of drug-resistant cell lines. Methods: BOLD-100-001 is a multicenter, prospective, two-stage, non-randomized Phase 1b dose escalation and expansion study of BOLD-100 in combination with FOLFOX chemotherapy for selected advanced solid gastrointestinal (GI) tumors: colorectal (CRC), pancreatic (PANC), gastric (GC) and bile duct cancers (BDC). Each patient will receive BOLD-100 along with FOLFOX chemotherapy on Day 1 of each 14-day cycle. In the dose-escalation phase (Part A), patients will be enrolled to determine the combination recommended dose using a standard 3+3 design. In the dose-expansion phase (Part B), up to 80 patients with selected GI tumors will be enrolled in 5 cohorts (comprising the 4 GI cancers referred) and treated with BOLD-100 at the recommended dose and FOLFOX, until progressive disease or unacceptable toxicity. In Part A dose-escalation, the primary objective is to assess the safety, tolerability and maximum tolerated dose. The Part B dose-expansion will assess the efficacy (progression free survival, overall survival and response rate), of FOLFOX chemotherapy plus BOLD-100. Secondary objectives in Part A and B include the assessment of pharmacokinetic and pharmacodynamic parameters and potential biomarkers predictive of efficacy. Eligible patients will have previously treated histologically/cytologically confirmed metastatic/unresectable GI tumor (CRC, PANC, GC or BDC), measurable disease per RECIST criteria, an ECOG performance score of 0 or 1, and adequate organ function. In Part A, no formal statistical hypotheses will be tested; analysis of the data will focus on comparisons of safety and dose-limiting toxicities between cohorts and only descriptive methods will be used. In Part B, Bayesian modelling will be used to continually reassess the efficacy endpoints: progression free survival, overall survival and objective response rates. The study was opened for enrollment in August 2020; approximately 25-30 patients will be screened to achieve up to 20 patients in Part A and up to 80 patients will be enrolled in Part B with a maximum of 25 patients per arm. Clinical trial information: NCT04421820.

Single-agent regorafenib is approved in Canada and in the US for patients with metastatic colorectal cancer (mCRC) who have failed previous lines of therapy1. Identification of prognostic biomarkers is crucial to ensure the best therapeutic strategies for mCRC patients. The goal of this clinical study (NCT01949194) was to explore putative molecular signatures of response and resistance to regorafenib in metastatic tumors and serial blood samples. We used a multi-omics approach to profile metastatic tumor tissues and serial blood samples from 47 mCRC patients who received single-agent regorafenib as second-line therapy after failing first-line therapy with an oxaliplatin or irinotecan-containing regimen with or without bevacizumab. Whole exome sequencing was performed to assess both the mutational and copy number (CN) landscapes of metastatic tissues from 29 patients and the transcriptome was interrogated using RNA sequencing. A 14-gene panel was used to profile serial plasma samples. Molecular aberrations were then correlated with lesion-specific treatment response using RECIST 1.1 and progression free survival (PFS) to investigate potential associations.The copy number aberration (CNA) landscape of metastatic tumors was assessed using Nexus Copy Number Software and 20 significant focal aberrations were identified using Genomic Identification of Significant Target in Cancer (GISTIC) test (q-bound Citation Format: Karen Gambaro, Maud Marques, Suzan McNamara, Mathilde Couetoux du Tertre, Cyrla Hoffert, Archana Srivastava, Sophie Mathieu, Anna schab, Thierry Alcindor, Adrian Langleben, Lucas Sideris, Mahmoud Adbelsalam, Mustapha Tehfe, Gerald Batist, Petr Kavan. A Phase II exploratory study to identify biomarkers prognostic of clinical response to regorafenib in patients with metastatic colorectal cancer who have failed first-line therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4325.

Single-agent immune checkpoint inhibition has not shown activities in advanced refractory colorectal cancer (CRC), other than in those patients who are microsatellite-instability high (MSI-H).To evaluate whether combining programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibition improved patient survival in metastatic refractory CRC.A randomized phase 2 study was conducted in 27 cancer centers across Canada between August 2016 and June 2017, and data were analyzed on October 18, 2018. Eligible patients had histologically confirmed adenocarcinoma of the colon or rectum; received all available standard systemic therapies (fluoropyrimidines, oxaliplatin, irinotecan, and bevacizumab if appropriate; cetuximab or panitumumab if RAS wild-type tumors; regorafenib if available); were aged 18 years or older; had adequate organ function; had Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease.We randomly assigned patients to receive either 75 mg of tremelimumab every 28 days for the first 4 cycles plus 1500 mg durvalumab every 28 days, or best supportive care alone (BSC) in a 2:1 ratio.The primary end point was overall survival (OS) and a 2-sided P.10 was considered statistically significant. Circulating cell-free DNA from baseline plasma was used to determine microsatellite instability (MSI) and tumor mutation burden (TMB).Of 180 patients enrolled (121 men [67.2%] and 59 women [32.8%]; median [range] age, 65 [36-87] years), 179 were treated. With a median follow-up of 15.2 months, the median OS was 6.6 months for durvalumab and tremelimumab and 4.1 months for BSC (hazard ratio [HR], 0.72; 90% CI, 0.54-0.97; P = .07). Progression-free survival was 1.8 months and 1.9 months respectively (HR, 1.01; 90% CI, 0.76-1.34). Grade 3 or 4 adverse events were significantly more frequent with immunotherapy (75 [64%] patients in the treatment group had at least 1 grade 3 or higher adverse event vs 12 [20%] in the BSC group). Circulating cell-free DNA analysis was successful in 168 of 169 patients with available samples. In patients who were microsatellite stable (MSS), OS was significantly improved with durvalumab and tremelimumab (HR, 0.66; 90% CI, 0.49-0.89; P = .02). Patients who were MSS with plasma TMB of 28 variants per megabase or more (21% of MSS patients) had the greatest OS benefit (HR, 0.34; 90% CI, 0.18-0.63; P = .004).This phase 2 study suggests that combined immune checkpoint inhibition with durvalumab plus tremelimumab may be associated with prolonged OS in patients with advanced refractory CRC. Elevated plasma TMB may select patients most likely to benefit from durvalumab and tremelimumab. Further confirmation studies are warranted.ClinicalTrials.gov Identifier: NCT02870920.

4032 Background: Pembrolizumab provides effective antitumor immunity and durable responses in patients (pts) with advanced, colorectal cancer (CRC) with microsatellite instability-high (MSI-H) tumors. We present data on antitumor immunity with pembrolizumab in pts from the phase 2, KEYNOTE-164 study who had approximately 3 years of follow-up, and in pts re-treated after disease progression. Methods: KEYNOTE-164 enrolled pts with metastatic MSI-H CRC, MSI-H status confirmed locally by IHC or PCR, and ≥2 (cohort A) or ≥1 (cohort B) prior lines of therapy (fluoropyrimidine, oxaliplatin, irinotecan, or anti VEGF/EGFR). Eligible pts received pembrolizumab 200 mg Q3W for 2y (35 administrations) or until progression, unacceptable toxicity, or withdrawal. Pts who stopped pembro due to a confirmed CR or after completing 2y of treatment and who progressed after stopping were eligible for re-treatment with up to 17 administrations in the second-course phase, at investigator discretion. Tumor response was assessed Q9W per RECIST v1.1 by independent review. The primary endpoint was ORR. Secondary endpoints included DOR, PFS, OS, and safety. The data cutoff date was Sep 9, 2019. Results: At data cutoff, the median follow-up was 31.4 mo (range, 0.2-47.8) for 61 pts in cohort A and 36.1 mo (0.1-39.3) for 63 pts in cohort B. ORR was 32.8% (3CR, 17PR; 95% CI% 21.3-46.0) for cohort A and 34.9% (8CR, 14PR; 95% CI 23.3-48.0) in cohort B. Median DOR was not reached (NR [range, 6.2-41.3+]) and not reached (range, 3.9+ to 37.1+), respectively. Fifteen pts in cohort A and 17 in cohort B had ongoing responses at data cutoff. Median PFS was 2.3 mo (95% CI 2.1-8.1) with 3-yr PFS rate of 31% in cohort A and was 4.1 mo (2.1-18.9) with 3-yr PFS rate of 34% in cohort B. Median OS was 31.4 mo (21.4-NR) with 3-yr OS rate of 49% in cohort A and was not reached (19.2-NR) with 3-yr OS rate of 52% in cohort B. Nine pts (6 in cohort A, 3 in cohort B) had a second course of treatment. The best response in second course was PR in 1 patient each in cohort A and B. Grade 3-4 drug-related adverse events occurred in 10 (16%) pts in cohort A and 8 (13%) pts in cohort B. No grade 5 drug-related events occurred. Conclusions: After approximately 3 y of follow-up, pembrolizumab continues to provide effective long-term antitumor immunity with durable responses, with small numbers of drug-related adverse events and no drug-related deaths in pts with advanced, MSI-H CRC. Clinical trial information: NCT02460198 .

This study evaluated safety and quality of life in patients with metastatic colorectal cancer undergoing treatment with aflibercept and FOLFIRI (fluorouracil, leucovorin, irinotecan). Most patients treated with this combination experienced either improvement or stability in quality of life scores. Aflibercept plus FOLFIRI is tolerable in the treatment of patients with metastatic colorectal cancer with a safety profile similar to that seen in previous studies of these individual medications. Background: The objectives of this study were to evaluate the safety profile of aflibercept and health-related quality of life (HRQL) in patients with metastatic colorectal cancer (mCRC) provided with aflibercept access before marketing authorization. Patients and Methods: Patients received aflibercept followed by FOLFIRI (fluorouracil, leucovorin, irinotecan) on day 1 of a 2-week cycle until disease progression, unacceptable toxicity, death, or patient/investigator decision to discontinue. Treatment-emergent adverse events (TEAEs) were evaluated, and HRQL was assessed at baseline, cycle 3, and every other cycle using the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30, EORTC QLQ-CR29, and EuroQol 5-Dimensions 3-Levels questionnaires (NCT01571284). Results: Overall, 779 adult patients with mCRC, who received >= 1 prior oxaliplatin-based regimen and had disease progression during or following their last administration of oxaliplatin-based chemotherapy, were enrolled. At data cutoff, all patients had discontinued treatment, mainly owing to disease progression (51.7%). The most common TEAEs of any grade were diarrhea (61.6%), hypertension (48.4%), and nausea (43.3%). The most common grade 3/4 TEAEs were hypertension (24.1%), neutropenia (23.1%), and diarrhea (15.3%). Clinically meaningful changes in HRQL were reported for all measures. Most patients either had an improvement in their HRQL scores or remained stable during the treatment period based on patient-reported outcomes. Conclusion: The data from this study support the tolerability of the combination of aflibercept and FOLFIRI in a setting that more closely approximates real life in patients with mCRC who failed to respond to oxaliplatin-based chemotherapy, and also suggest an improvement in HRQL.

673 Background: Folfirinox (FFX) and Gemcitabine with nab-Paclitaxel (GN) are both proven to be superior to Gemcitabine (G) in the first line treatment (1LTx) for advanced pancreatic cancer (APC). Yet, the optimal 1LTx selection nor sequential Tx (ST) has not been fully established. Therefore, the best choice for 1LTx is a matter of debate often influenced by access to drugs. This analysis was conducted to compare outcomes based on 1Ltx selection and ST in APC. Methods: We assessed patients (pts) with APC who received either FFX or GN as 1LTx during 2010-2019 at three Canadian institutions. As well as the ST used. The main objective was to assess survival. Kaplan method and log-rank test were used for survival curves. Results: This retrospective study included 231 pts; 1LTx included 143 pts on FFX and 88 pts on GN. FFX pts were predominantly male; 89(62.2%) vs 46(52.3%) and slightly younger (median age 62 vs 66) than GN. WHO performance status (PS) of 0 were 38 (28.4%) vs 14 (16.5%) and 1 were 90 (67.2%) vs 65 (76.5%) respectively. There were more grade 3-4 toxicity in FFX vs GN group: GI 55 (38.5%) vs 15 (17%) and hematologic 51 (35.4%) vs 20 (22.7%) respectively. Grade 3-4 neutropenia rates were similar in both regimens. The median PFS of FFX was 5.5 months (95% CI: 5.0-6.7) vs 5.1 (95% CI: 3.8-7.1) with GN (p=0.37). The median OS with FFX was 9.3 months (95% CI: 7.5-11.1) vs 10.2 (95% CI: 6.8-11.3) with GN (p=0.81). There were not statically significant. Table shows Tx frequency across 4LTx. 2LTx and beyond regimens included G, GN, FFX, Capecitabine, Irinotecan liposome plus 5-FU, Irinotecan and clinical trials. Conclusions: Our results revealed that pts who received 1LTx FFX or GN had similar PFS and OS even though 1LTx FFX group was younger with better PS, allowing to continue 2-4LTx more frequently when compare with 1LTx GN group. Therefore, 1LTx selection appear to have more impact in our pts rather than ST, whereas GN is less toxic and seems a preferable 1LTx choice for most pts. FFX could be reserved for young high-performance pts. [Table: see text]

719 Background: Although Folfirinox (FFX) prolonged survival in metastatic and adjuvant setting, the role of preoperative FFX is still controversial. Our aim is to evaluate how surgery after neoadjuvant FFX with or without radiotherapy (RT) affects the clinical outcome in these patients. Methods: This is a single arm, open-label, phase 2 prospective study. Based on resectability criteria (NCCN-V.1.2017), patients prospectively were divided into 3 groups of resectable, borderline resectable (BR), locally advanced (LA). Patients received 6 cycles of preoperative FFX. Patients with adequate response, underwent resection. Continuation of chemotherapy or radiation was given to the patients who were deemed unresectable after 6 cycles. Primary objective is time to progression (TTP), and secondary objectives are safety, R0/R1 resection rate, response rate (RR) and overall survival (OS). Results: 20 consecutive patients with pancreatic adenocarcinoma enrolled. The frequency of each group was 4, 8, 8 patients, respectively. Median age was 64 years old (range, 49-78). 45% of patients had primary tumor in head or uncinate process. 25% of cases presented with normal CA 19-9 value. 85% (17/20) of patients completed the preoperative treatment. Folfirinox was given within median of 11.5 weeks (range, 8-17) and median of 6 cycles (range, 1-7). Median relative dose intensity (RDI) was 85.89%. Grade III-IV (G3+4) adverse event (CTCAE-4.03) observed in 47.4% (9/19). RR (RECIST) was 89% (16/18). Best response was partial response (PR) and stable disease (SD) with 22.2% (4/18) and 66.7% (12/18). Resection rate was 64.3% (9/14, 1 case scheduled for resection). R0 and negative lymph node (LN) achieved in 87.50% (7/8) and 62.50% (5/8) of patients. Complete pathological response (cPR) was seen in one patient 12.5% (1/8) who preoperatively reported as SD. Patients TTP and OS will be reported during the meeting. Conclusions: Preoperative FFX was associated with high clinical and pathological response rate translating in high resection rate in majority of BRPC and LAPC, and appears to be a safe treatment strategy. Patients received higher FFX dose intensity than it was reported in adjuvant setting. However, these results need to be assessed in a randomized trial. Clinical trial information: NCT03167112.

Background Pembro, a PD-1 inhibitor, confers durable benefit in many tumor types but has limited efficacy in non–microsatellite instability–high (MSI-high)/pMMR mCRC. Chemotherapies that include 5-fluorouracil (5-FU), oxaliplatin and irinotecan, which are commonly used to treat mCRC, may modulate intrinsic tumor immunogenicity and sensitize tumors to immunotherapy agents. In the phase 1b KEYNOTE-651 study (NCT03374254), pembro + mFOLFOX7 (cohort B) or pembro + FOLFIRI (cohort D) was evaluated in patients with non–MSI-high/pMMR mCRC. Methods Patients were ≥18 years with non–MSI-high/pMMR mCRC, Eastern Cooperative Oncology Group performance status 0/1, and no prior systemic chemotherapy for stage IV mCRC (cohort B) or 1 prior therapy including a fluoropyrimidine + oxaliplatin-based regimen (cohort D). Patients received pembro 200 mg every 3 weeks (Q3W) + mFOLFOX7 (oxaliplatin [85 mg/m2]; leucovorin [400 mg/m2]; 5-FU [2400 mg/m2]) Q2W (cohort B) or pembro 200 mg Q3W + FOLFIRI (irinotecan [180 mg/m2]; leucovorin [400 mg/m2]; 5-FU [2400 mg/m2]) Q2W (cohort D). Primary objectives were safety/tolerability and establishment of the recommended phase 2 dose (RP2D); the secondary objective was objective response rate. Results At data cutoff (Feb 18, 2019), 15 patients in cohort B and 16 in cohort D started treatment; median follow-up was 6.8 months (cohort B) and 5.7 months (cohort D). Treatment was discontinued in 4 patients (27%) in cohort B (adverse event [AE], n = 1 [7%]; PD, n = 3 [20%]) and 9 patients (56%) in cohort D (AEs, PD, patient withdrawal; n = 3 [19%] each). There was 1 dose-limiting toxicity in cohort D: grade 3 small-intestinal obstruction. See RP2Ds for cohorts B and D in the Methods section. All patients had ≥1 treatment-related AE (TRAE). Grade 3 TRAEs occurred in 8 patients each in cohort B (53%) and cohort D (50%), most commonly anemia and neutropenia (13% each) in cohort B and neutropenia, diarrhea, fatigue, and leukopenia (13% each) in cohort D. There were no grade 4-5 TRAEs. Efficacy results will be presented. Conclusions Pembro in combination with mFOLFOX7 or FOLFIRI was safe and tolerable in patients with mCRC. Clinical trial identification NCT03374254; Release date: December 15, 2017. Editorial acknowledgement Jacqueline Kolston, PhD, of the ApotheCom pembrolizumab team (Yardley, PA, USA); Funded by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Legal entity responsible for the study Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and Array BioPharma. Funding Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and Array BioPharma. Disclosure R. Kim: Advisory / Consultancy, Research grant / Funding (institution): Bayer; Advisory / Consultancy, Research grant / Funding (institution): BMS; Advisory / Consultancy, Speaker Bureau / Expert testimony: Lilly; Research grant / Funding (institution): Eisai. J. Kortmansky: Research grant / Funding (institution): Merck; Research grant / Funding (institution): Roche. L. Wong: Research grant / Funding (institution): Astellas Pharma Global Development, Inc./Astellas US, Inc.; Research grant / Funding (institution): BeiGene, Ltd; Research grant / Funding (institution): Exelixis, Inc.; Research grant / Funding (institution): Merck; Research grant / Funding (institution): NovoCure, Inc.; Research grant / Funding (institution): Pierre Fabre Medicament; Research grant / Funding (institution): PledPharma AB; Research grant / Funding (institution): SynCore Biotechnology Co., Ltd.; Research grant / Funding (institution): Halozyme, Inc.; Research grant / Funding (institution): Pharmacyclics, Inc.; Research grant / Funding (institution): TESARO; Research grant / Funding (institution): EMD Serono; Research grant / Funding (institution): Array. M. Tehfe: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Merck; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Celgene; Honoraria (self): Ipsen; Advisory / Consultancy: BMS; Advisory / Consultancy: Takeda; Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Taisho. J.J. Li: Full / Part-time employment: Merck & Co., Inc. M. Lee: Shareholder / Stockholder / Stock options, Full / Part-time employment: Merck & Co., Inc. C. Mayo: Full / Part-time employment: Merck & Co., Inc. P. Marinello: Shareholder / Stockholder / Stock options, Full / Part-time employment: Merck & Co., Inc. E. Chiorean: Advisory / Consultancy: Ipsen; Advisory / Consultancy: Eisai; Advisory / Consultancy: Halozyme; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Seattle Genetics; Advisory / Consultancy: Array; Advisory / Consultancy: Five Prime; Research grant / Funding (institution): Boehringer Ingelheim; Research grant / Funding (institution): Celgene; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): Lilly; Research grant / Funding (institution): AstraZeneca; Travel / Accommodation / Expenses: Halozyme; Research grant / Funding (institution): Merck; Research grant / Funding (institution): BMS; Research grant / Funding (institution): Ignyta/Roche; Research grant / Funding (institution): Stemline; Research grant / Funding (institution): Macrogenetics. All other authors have declared no conflicts of interest.

There are few effective treatments for recurrent glioblastoma multiforme (GBM). We present a patient with recurrent GBM who achieved a prolonged response to treatment with afatinib, an irreversible ErbB family blocker, plus temozolomide. A 58-year-old female patient was diagnosed with multifocal primary GBM. After surgical resection, first-line therapy comprised radiotherapy and temozolomide. Following disease progression after 3 temozolomide cycles, the patient entered a phase I/II clinical trial of afatinib (20–40 mg daily for 28 days) plus temozolomide (50 mg/m2 every 21/28 days). Next-generation sequencing analysis of the brain tumor specimen was performed. At the last assessment, 63 treatment cycles had been completed and the patient had survived for ~5 years since recurrence. Significant disease regression was observed after 5 cycles and was maintained during long-term follow-up. Adverse events were consistent with the known tolerability profile of afatinib and were managed by treatment interruption/dose reduction. The patient had several epidermal growth factor receptor (EGFR) aberrations, including gene amplification and EGFRvIII positivity. Three somatic mutations were identified, including an unprecedented extracellular-domain substitution (D247Y). The patient has survived ~6-fold longer than normally expected in patients with recurrent GBM. The complex EGFR genotype may underlie sustained response to afatinib plus temozolomide.

Summary Background Rindopepimut (also known as CDX-110), a vaccine targeting the EGFR deletion mutation EGFRvIII, consists of an EGFRvIII-specific peptide conjugated to keyhole limpet haemocyanin. In the ACT IV study, we aimed to assess whether or not the addition of rindopepimut to standard chemotherapy is able to improve survival in patients with EGFRvIII-positive glioblastoma. Methods In this randomised, double-blind, phase 3 trial, we recruited patients aged 18 years and older with glioblastoma from 165 hospitals in 22 countries. Eligible patients had newly diagnosed glioblastoma confirmed to express EGFRvIII by central analysis, and had undergone maximal surgical resection and completion of standard chemoradiation without progression. Patients were stratified by European Organisation for Research and Treatment of Cancer recursive partitioning analysis class, MGMT promoter methylation, and geographical region, and randomly assigned (1:1) with a prespecified randomisation sequence (block size of four) to receive rindopepimut (500 μg admixed with 150 μg GM-CSF) or control (100 μg keyhole limpet haemocyanin) via monthly intradermal injection until progression or intolerance, concurrent with standard oral temozolomide (150–200 mg/m 2 for 5 of 28 days) for 6–12 cycles or longer. Patients, investigators, and the trial funder were masked to treatment allocation. The primary endpoint was overall survival in patients with minimal residual disease (MRD; enhancing tumour 2 post-chemoradiation by central review), analysed by modified intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01480479. Findings Between April 12, 2012, and Dec 15, 2014, 745 patients were enrolled (405 with MRD, 338 with significant residual disease [SRD], and two unevaluable) and randomly assigned to rindopepimut and temozolomide (n=371) or control and temozolomide (n=374). The study was terminated for futility after a preplanned interim analysis. At final analysis, there was no significant difference in overall survival for patients with MRD: median overall survival was 20·1 months (95% CI 18·5–22·1) in the rindopepimut group versus 20·0 months (18·1–21·9) in the control group (HR 1·01, 95% CI 0·79–1·30; p=0·93). The most common grade 3–4 adverse events for all 369 treated patients in the rindopepimut group versus 372 treated patients in the control group were: thrombocytopenia (32 [9%] vs 23 [6%]), fatigue (six [2%] vs 19 [5%]), brain oedema (eight [2%] vs 11 [3%]), seizure (nine [2%] vs eight [2%]), and headache (six [2%] vs ten [3%]). Serious adverse events included seizure (18 [5%] vs 22 [6%]) and brain oedema (seven [2%] vs 12 [3%]). 16 deaths in the study were caused by adverse events (nine [4%] in the rindopepimut group and seven [3%] in the control group), of which one—a pulmonary embolism in a 64-year-old male patient after 11 months of treatment—was assessed as potentially related to rindopepimut. Interpretation Rindopepimut did not increase survival in patients with newly diagnosed glioblastoma. Combination approaches potentially including rindopepimut might be required to show efficacy of immunotherapy in glioblastoma. Funding Celldex Therapeutics, Inc.

Importance Previous communication has reported significant improvement in overall survival (OS) when using doxorubicin plus sorafenib in the treatment of advanced hepatocellular cancer (HCC). Objective To determine if doxorubicin added to sorafenib therapy improves OS, with stratification for locally advanced and metastatic disease. Design, Setting, and Participants This unblinded randomized phase 3 clinical trial was led by Alliance in collaboration with Eastern Cooperative Oncology Group–American College of Radiology Imaging Network, Canadian Cancer Trials Group, and Southwest Oncology Group. It was launched in February 2010 and completed in May 2015; data were also analyzed during this time frame. Patients with histologically proven advanced HCC, no prior systemic therapy, Child-Pugh grade A score, Eastern Cooperative Oncology Group performance status of 0 to 2 (later amended to 0-1), and adequate hematologic, hepatic, renal, and cardiac function were eligible. The OS primary end point had a final analysis planned with 364 events observed among 480 total patients with 90% power to detect a 37% increase in median OS. Interventions or Exposures Patients received either 60 mg/m2of doxorubicin every 21 days plus 400 mg of sorafenib orally twice daily or the sorafenib alone, adjusted to half doses for patients with bilirubin levels of 1.3 to 3.0 mg/dL. Main Outcomes and Measures The primary end point was OS, and progression-free survival (PFS) was a secondary end point. Results Of 356 patients included in the study, the mean (SD) age was 62 (10.1) years, and 306 (86.0%) were men. Although it was planned to include 480 patients, the study was halted after accrual of 356 patients (180 patients treated with doxorubicin plus sorafenib and 176 with sorafenib alone) with a futility boundary crossed at a planned interim analysis. Median OS was 9.3 months (95% CI, 7.3-10.8 months) in the doxorubicin plus sorafenib arm and 9.4 months (95% CI, 7.3-12.9 months) in the sorafenib alone arm (hazard ratio, 1.05; 95% CI, 0.83-1.31). The median PFS was 4.0 months (95% CI, 3.4-4.9 months) in the doxorubicin plus sorafenib arm and 3.7 months (95% CI, 2.9-4.5 months) in the sorafenib alone arm (hazard ratio, 0.93; 95% CI, 0.75-1.16). Grade 3 or 4 neutropenia and thrombocytopenia adverse events occurred in 61 (36.8%) and 29 (17.5%) patients, respectively, being treated with doxorubicin plus sorafenib vs 1 (0.6%) and 4 (2.4%) patients treated with sorafenib. Conclusions and Relevance This multigroup study of the addition of doxorubicin to sorafenib therapy did not show improvement of OS or PFS in patients with HCC. Trial Registration ClinicalTrials.gov identifier:NCT01015833

Background FOLFIRINOX (FFX) and Gemcitabine with nab-Paclitaxel (GN) are both proven to be superior to Gemcitabine in first line treatment for advanced pancreatic cancer (APC). However, there has been no phase 3 randomized controlled trials to prove FFX is superior to GN in APC. This population-based cohort study was conducted to compare efficacy and safety profiles of the two standard regimens in APC. Methods In this retrospective cohort study, we evaluated all newly diagnosed patients (pts) with APC who received either FFX or GN as first line therapy during 2010-2018 at three Canadian institutions. The primary objective was to assess survival. Secondary objective was to compare safety profile of the two regimens. Kaplan Meier method and log-rank test were used for survival curves. Results There were 231 eligible pts identified: 143 received FFX and 88 received GN. FFX pts were slightly younger than GN (median age: 62 (IQR: 56-67) vs 66 (IQR: 58-73) respectively). There were predominantly more males: FFX 89 (62.2%) vs GN 46 (52.3%). WHO performance status (PS) of 0 were 38 (28.4%) vs 14 (16.5%) and 1 were 90 (67.2%) vs 65 (76.5%) respectively. The median progression-free survival (PFS) of FFX was 5.5 months (mts) (95% CI: 5.0-6.7) vs 5.1 mts (95% CI: 3.8-7.1) with GN (p = 0.37). The median overall survival (OS) with FFX was 9.3 mts (95% CI: 7.5 – 11.1) vs. 10.2 mts (95% CI: 6.8-11.3) with GN (p = 0.81). On multivariate analysis chemotherapy regimen was not correlated with PFS or OS. There were more grade 3-4 toxicity in FFX vs GN group: diarrhea – 22 (15.4%) vs 3 (3.4%) (p = 0.004), nausea – 20 (14%) vs 6 (6.8%), vomiting – 13 (9.1%) vs 6 (6.8%), peripheral sensory neuropathy (PSN) – 8 (5.6%) vs 3 (3.4%), thrombocytopenia – 28 (19.6%) vs 5 (5.7%) (p = 0.003) respectively. Gr 3-4 neutropenia rates were similar in both regimens: 23 (16%) in FFX vs 15 (17%) in GN. Conclusions Our results revealed that FFX or GN had comparable survival and safety profiles. Given lower Gr 3-4 toxicity profile of GN regimen, GN is likely preferable choice for majority of pts. FFX could be reserved for young high performance pts. Legal entity responsible for the study Segal Cancer Centre Jewish General Hospital. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

3512 Background: Targeting both PD-L1 and CTLA-4 may be synergistic immunotherapy approaches. CO.26 evaluated if dual inhibition leads to improved pt survival vs BSC alone in rmCRC. Methods: rmCRC pts were randomized 2:1 to D+T vs BSC. Treatment consisted of D (1500 mg) D1 q 28 days and T (75 mg) D1 for first 4 cycles, and supportive measures. Primary endpoint was overall survival (OS). Two-sided p < 0.10 was considered statistically significant. Cell-free (cf)DNA sequencing for MSI and TMB used GuardantOMNI panel and baseline plasma. Results: From 08/2016-06/2017, 180 pts were enrolled. Pt characteristics were balanced between arms. At median follow-up of 15.2 months (mos), median OS was 6.6 mos for D+T and 4.1 mos for BSC (p = 0.07; Hazard ratio (HR): 0.72, 90% confidence interval (CI): 0.54 – 0.97). Progression free survival (PFS) was 1.8 mos vs 1.9 mos, respectively (HR 1.01, 90% CI 0.76 – 1.34). Disease control rate (DCR) was 22.6% for D+T and 6.6% for BSC (p = 0.006). cfDNA analysis was successful in 168/169 pts (99.4%). Two pts were MSI-high. In 166 MSS pts, OS HR was 0.66 (p=0.024; 90% CI 0.49-0.89). Excluding the MSI-H cases (TMB of 74.7 and 247.1 mts/Mb), mean TMB was 20.4 ± 16.3 mts/Mb (range: 0.96 – 114.0). In MSS pts, a pre-specified cutpoint of 20 mts/Mb stratified pts into high and low TMB groups but was not predictive for OS , PFS, or DCR (interaction p-values > 0.7). Using a minimum p-value approach, pts with TMB >28 mts/Mb (21% of MSS pts) had the greatest OS benefit (HR 0.34, 90% CI 0.18-0.63) for D+T (interaction p = 0.07). High TMB was associated with a trend in worse prognosis for OS in the BSC arm using both 20 mts/Mb (HR 1.26, 90% CI 0.76-2.12) and 28 mts/Mb (HR 2.59 90% CI 1.46-4.62) cutpoints. Conclusions: D+T significantly prolonged OS in pts with rmCRC. High TMB may select a group of MSS pts who benefit from D+T. Plasma TMB appeared prognostic in the BSC arm. This is the first study showing combined PD-L1 and CTLA-4 inhibition prolongs survival in pts with MSS rmCRC. Updated results based on deaths in more than 90% of pts will be presented. Clinical trial information: NCT02870920.

481 Background: D is a human monoclonal antibody (mAb) that inhibits binding of programmed cell death ligand 1 (PD-L1) to its receptor. T is a mAb against the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Targeting both PD-L1 and CTLA-4 may have additive/synergistic activity as the mechanisms of action of CTLA-4 and PD-L1 inhibition are non-redundant. This study evaluated whether combining PD-L1 and CTLA-4 inhibition would lead to improved pt survival vs BSC alone in rCRC. Methods: Pts with rCRC were randomized 2:1 to D+T vs BSC . Pts were eligible if they failed all standard regimens; containing a fluoropyrimidine, irinotecan and oxaliplatin (and an EGFR inhibitor if Ras wild type). Prior treatment (Tx) with anti-VEGF agents or TAS-102 was permitted but not mandatory. Tx consisted of D (1500 mg) D1 q 28 days and T (75 mg) D1 for first 4 cycles, and all appropriate supportive measures. Primary endpoint was overall survival (OS) and a two-sided p-value < 0.10 was considered statistically significant. Results: Between August 2016 and June 2017, 180 pts were enrolled and 179 treated as randomized. Pt baseline characteristics were balanced. 85% of pts received ≥ 90% of planned doses of D and T. No pts with known defective mismatch repair (dMMR) tumors were enrolled. With a median (med) follow-up of 15.2 months (mo), the med OS was 6.6 mo for D+T and 4.1 mo for BSC (p = 0.07; Hazard ratio (HR): 0.72, 90% confidence interval (CI): 0.54–0.97). Med progression free survival was 1.8 mo and 1.9 mo respectively (HR 1.01, 90% CI 0.76–1.34; p=0.97). Disease control rate was 22.7% for D+T and 6.6% for BSC (p = 0.006). Grade 3/4 abdominal pain, fatigue, lymphocytosis and eosinophilia were significantly higher in D+T. At 16 weeks, there was significantly less deterioration on EORTC QLQ-C30 physical function for D+T. Confirmation of MMR status is ongoing. Conclusions: D+T significantly prolonged OS in pts with rCRC and preserved quality of life. Adverse events were more frequent with D+T. This is the first study showing that combined PD-L1 and CTLA-4 inhibition prolongs survival in pts with advanced refractory CRC not selected for dMMR. Clinical trial information: NCT02870920.

400 Background: Since 2011, options for treatment of metastatic pancreatic cancer (mPC) have improved with the use of nab-paclitaxel plus gemcitabine (n-PGEM) or FOLFIRINOX (FFX) as first line treatments (1LTx). In 2016, Nanoliposomal irinotecan plus 5FU (nal-IRI-5FU) demonstrated efficacy in 2LTx. Yet, optimal sequential Tx has not been established. Methods: We evaluated oncologist-selected Tx algorithms and resultant progression free & overall survival (PFS, OS) for pts with mPC from 2010 and 2018 at the Jewish General Hospital, Montreal, QC. This retrospective study included 203 pts with mPC (33 to 89 years, 54% male). Results: 1LTx included 66 pts on FFX, 60 pts on n-PGEM, and 66 pts on single-agent GEM. The remaining pts received Capecitabine (CAP) or another Tx (N = 11). Mean PFS in FFX, n-PGEM, and GEM groups was 5.07, 5.52, and 4.10 months, respectively (progression was 1˚ or 2˚ disease progression or a change of Tx due to adverse events or intolerance). Only the FFX and GEM groups were significant when compared (p = 0.049). Only 43.8% of pts (N = 89/203) advanced to 2LTx most receiving GEM (N = 27), n-PGEM (N = 21), or FFX (N = 11), PFS 3.87, 7.04, and 2.30 months, respectively. FFX and n-PGEM groups were significant when compared (p=0.011). CAP and nal-IRI-5FU were 2LTx options for 25.8% (N=23/89) and 7.9% (N = 7/89) of pts, respectively. For 30 pts in 3LTx, Txs included: nal-IRI-5FU (N = 8), clinical trials (CT) (N = 7), GEM (N = 5), FFX (N = 4), n-PGEM (N = 2), CAP (N = 2) and Irinotecan (IRI) (N = 2). Only 7 pts received 4LTx: GEM (N = 3), CAP (N = 2), CT (N = 1), and IRI (N = 1). Median OS from start of 1LTx for pts in FFX (N = 60), n-PGEM (N = 41), and GEM (N = 60) groups was 11.42, 9.50, and 6.23 months, respectively. (Excluding pts on ongoing tx and other censored data points). GEM tx was a significant prognostic factor for shorter OS, GEM verus FFX, HR 1.673 (1.165 to 2.402, p = 0.0053), GEM versus n-PGEM, HR 1.511 (1.012 to 2.258, p = 0.0437). No difference in survival was seen between FFX and n-PGEM groups, HR 0.903 (95% CI 0.605-1.349, p = 0.6196). Conclusions: Though FFX and n-PGEM are considered mainstays of 1LTx, GEM was chosen by physicians in ~1/3 of cases despite reduced PFS. Pts on FFX or n-PGEM had better OS compared to GEM alone, as expected. Further investigation into Tx sequencing in this and larger cohorts, is needed.

BACKGROUND Irinotecan is cytotoxic in patients with advanced colorectal cancer (CRC). SN-38 (10-hydroxy-7-ethyl-camptothecin) is the active metabolite of irinotecan. Attachment of polyethylene glycol (PEG) polymer chains (pegylation) to SN-38 (EZN-2208) increases the solubility, exposure, and half-life of SN-38. Preclinical studies demonstrated superior in vitro efficacy of EZN-2208 when it was tested in irinotecan-refractory human CRC cell lines. METHODS Patients with metastatic or locally recurrent CRC who had previously received 5-flurouracil (5-FU), oxaliplatin, and irinotecan were assigned to receive EZN-2208 monotherapy (9 mg/m2 on days 1, 8, and 15 every 28 days for patients with KRAS-mutant tumors only [arm A]), and patients with KRAS wild-type tumors were randomized (2:1) to receive either EZN-2208 plus cetuximab (400 mg/m2 loading dose on day 1 followed by 250 mg/m2 weekly starting on day 8 [arm B]) or irinotecan 125 mg/m2 on days 1 and 8 every 21 days plus cetuximab at the same doses indicated above (arm C). RESULTS The overall response rate and progression-free survival were 0% and 1.8 months, respectively, in arm A; 10.7% and 4.9 months (95% confidence interval [CI], 3.2-5.8 months), respectively, in arm B; and 14.3% and 3.7 months (95% CI, 2.1-5.8 months), respectively, in arm C. EZN-2208 was well tolerated in combination with cetuximab. No statistically significant difference in survival was observed between arm B (9.8 months; 95% CI, 7.2-11.2 months) and arm C (9.1 months; 95% CI, 6.0-13.0 months). CONCLUSIONS EZN-2208, either as monotherapy or in combination with cetuximab, was well tolerated in patients with refractory CRC. Overall survival and progression-free survival were similar in the cetuximab plus irinotecan arm and the EZN-2208 arm. Cancer 2013;119:4223–4230. © 2013 American Cancer Society.

Background:Bevacizumab, a humanized recombinant anti-vascular endothelial growth factor antibody, was approved in Canada in 2010 for the treatment of high-grade glioma. We report the effectiveness and safety of bevacizumab in the treatment of patients with recurrent high-grade gliomas at a single institution.Methods:Twenty-seven consecutive patients with high-grade glioma (anaplastic glioma and glioblastoma) at first or subsequent relapse were treated with bevacizumab alone or in combination with chemotherapy. The primary endpoint was progression-free survival (PFS) and secondary endpoints were objective response rate, six month PFS, overall survival (OS), and safety profile.Results:The clinical benefit rate (complete and partial responses plus stable disease) was 59%. Median PFS was 4.3 (95% CI, 3.0-10.9) months, with a six month PFS rate of 43%. Median OS after current relapse was 8.9 (95% CI, 5.8-not reached) months. Ten episodes of grade 3/4 adverse events were observed in nine patients, including fatigue (n = 3), thrombocytopenia (n = 4), and myelotoxicity, febrile neutropenia, and pulmonary embolism (each n = 1).Conclusions:We consider the efficacy and safety profile of bevacizumab is comparable to other cohorts of patients treated for recurrent high-grade glioma at other international institutions.