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Uncontrolled chemotherapy-induced nausea and vomiting (CINV) can reduce patients’ quality of life and may result in premature discontinuation of chemotherapy. Although nausea and vomiting are commonly grouped together, research has shown that antiemetics are clinically effective against chemotherapy-induced vomiting (CIV) but less so against chemotherapy-induced nausea (CIN). Nausea remains a problem for up to 68% of patients who are prescribed guideline-consistent antiemetics. Despite the high prevalence of CIN, relatively little is known regarding its etiology independent of CIV. In this review paper, we summarize a metagenomics approach to the study and treatment of CIN with the goal of encouraging future research. Metagenomics focuses on genetic risk factors, encompassing both human (i.e., host) and gut microbial genetic variation. Little work to date has focused on metagenomics as a putative biological mechanism of CIN. Metagenomics has the potential to be a powerful tool in advancing scientific understanding of CIN by identifying new biological pathways and intervention targets. Investigation of metagenomics in the context of well-established demographic, clinical, and patient-reported risk factors may help to identify patients at risk and facilitate prevention and management of CIN.

BACKGROUND: MMR proficient (pMMR) colorectal cancer (CRC) is usually unresponsive to immunotherapy. Recent data suggest that ibrutinib may enhance the anti-tumour activity of anti-PD-1 immunotherapy. In this study, we evaluated the safety and efficacy of ibrutinib plus pembrolizumab in refractory metastatic CRC. METHODS: This was a phase 1/2 study in patients with refractory metastatic pMMR CRC. The primary endpoints for phases 1 and 2 were maximum tolerated dose (MTD) and disease control rate, respectively. The secondary endpoints were safety, progression-free survival (PFS) and overall survival (OS). RESULTS: A total of 40 patients were enrolled. No dose-limiting toxicity was observed, and MTD was not identified. The highest tested dose of ibrutinib, 560 mg once daily, was combined with a fixed dose of pembrolizumab 200 mg every 3 weeks for the phase 2 portion. The most common grade 3/4 treatment-related adverse events were anaemia (21%), fatigue (8%) and elevated alkaline phosphatase (8%). Among 31 evaluable patients, 8 (26%) achieved stable disease, and no objective response was observed. The median PFS and OS were 1.4 and 6.6 months, respectively. CONCLUSION: Ibrutinib 560 mg daily plus pembrolizumab 200 mg every 3 weeks appears to be well tolerated with limited anti-cancer activity in metastatic CRC. CLINICALTRIALS.GOV IDENTIFIER: NCT03332498.

Background: The purpose of this study was to characterize pre-treatment non-contrast computed tomography (CT) and 18 F-fluorodeoxyglucose positron emission tomography (PET) based radiomics signatures predictive of pathological response and clinical outcomes in rectal cancer patients treated with neoadjuvant chemoradiotherapy (NACRT). Material and methods: An exploratory analysis was performed using pre-treatment non-contrast CT and PET imaging dataset. The association of tumor regression grade (TRG) and neoadjuvant rectal (NAR) score with pre-treatment CT and PET features was assessed using machine learning algorithms. Three separate predictive models were built for composite features from CT + PET. Results: The patterns of pathological response were TRG 0 (n = 13; 19.7%), 1 (n = 34; 51.5%), 2 (n = 16; 24.2%), and 3 (n = 3; 4.5%). There were 20 (30.3%) patients with low, 22 (33.3%) with intermediate and 24 (36.4%) with high NAR scores. Three separate predictive models were built for composite features from CT + PET and analyzed separately for clinical endpoints. Composite features with α = 0.2 resulted in the best predictive power using logistic regression. For pathological response prediction, the signature resulted in 88.1% accuracy in predicting TRG 0 vs. TRG 1–3; 91% accuracy in predicting TRG 0–1 vs. TRG 2–3. For the surrogate of DFS and OS, it resulted in 67.7% accuracy in predicting low vs. intermediate vs. high NAR scores. Conclusion: The pre-treatment composite radiomics signatures were highly predictive of pathological response in rectal cancer treated with NACRT. A larger cohort is warranted for further validation.

Background Biliary tract cancer (BTC) has a poor prognosis despite treatment with first-line gemcitabine and cisplatin. In BTC, PI3K/AKT pathway activation has been shown to increase resistance to chemotherapy, which may be overcome with PI3K inhibition. This phase 2 study evaluated the safety and efficacy of copanlisib, a PI3K inhibitor, with gemcitabine and cisplatin in advanced BTCs. The role of PTEN expression in outcomes was also explored. Methods Patients with advanced/unresectable BTC received gemcitabine, cisplatin, and copanlisib as their first-line treatment. The primary endpoint was progression-free survival (PFS) at 6 months. Secondary endpoints were the response rate (RR), median overall survival (OS)/PFS, and safety profile. An assessment of PTEN expression by immunohistochemistry was also performed along with molecular profiling. Results Twenty-four patients received at least 1 dose of the study drug. The PFS rate at 6 months was 51%; the median OS was 13.7 months (95% CI, 6.8-18.0 months), and the median PFS was 6.2 months (95% CI, 2.9-10.1 months). Nineteen patients were evaluable for RR: 6 patients achieved a partial response (31.6%), and 11 (57.9%) had stable disease. The most common grade 3/4 adverse events were a decreased neutrophil count (45.83%), anemia (25%), increased lipase (25%), and hypertension (20.8%). Twenty patients had tissue evaluable for the PTEN status. The PFS for low (n = 9) and high PTEN expression (n = 11) was 8.5 and 4.6 months, respectively (P = .19). The median OS for low and high PTEN expression groups was 17.9 and 7.0 months, respectively (P = .19). Conclusions The addition of copanlisib to gemcitabine and cisplatin does not improve PFS at 6 months. However, future studies using PTEN as a potential biomarker should be considered. Lay summary The addition of copanlisib, a PI3K inhibitor, to standard chemotherapy for advanced biliary tract cancers was assessed for efficacy and safety. Twenty-four patients with advanced biliary tract cancer received treatment in this study. There was no difference in survival with the addition of copanlisib in comparison with standard chemotherapy. Copanlisib may be more effective and increase survival in patients with low PTEN expression levels. Further studies are needed to confirm this. No unexpected adverse events occurred.

Precision medicine with genetic profiling of tumor tissue has become an essential part of routine clinical practice in colorectal cancer. However, tissue genetic profiling suffers from clonal evolution, tumor heterogeneity, and time needed to deliver critical information for prompt clinical decision making. In contrast, liquid biopsy with plasma circulating tumor DNA provides genetic and epigenetic information from both the primary and metastatic colorectal cancer, which can potentially capture tumor heterogeneity and evolution with time and treatment. In addition, liquid biopsy with circulating tumor DNA is minimally invasive, quicker, and easily repeatable with high patient compliance to provide both qualitative and quantitative molecular information in real-time. We provide an overview on the potential clinical applications of circulating tumor DNA in the screening, surveillance, and treatment monitoring of colorectal cancer.

Purpose: Patients with metastatic colorectal cancer refractory to chemotherapy have limited treatment options. Ensituximab (NEO-102) is a novel chimeric mAb targeting a variant of MUC5AC with specificity to colorectal cancer. Patients and Methods: Single-arm, phase II trial assessed the efficacy and safety of ensituximab in patients with advanced, refractory cancer who expressed MUC5AC antigen in tumor tissue. Ensituximab was administered intravenously every 2 weeks with 3 mg/kg as recommended phase II dose (RP2D). A minimum sample size of 43 patients was required on the basis of the assumption that ensituximab would improve median overall survival (OS) by 7 months using a one-sided significance level of 10% and 80% power. Written informed consent was obtained from all patients. Results: Sixty-three patients with advanced, refractory colorectal cancer were enrolled and 53 subjects were treated in phase II arm. Median age was 58 years and 46% of the patients were female. Among 57 evaluable patients, median OS was 6.8 months. No responses were observed, and stable disease was achieved in 21% of the patients. The most common treatment-related adverse events (AE) at RP2D included fatigue (38%), anemia (30%), nausea (15%), vomiting (11%), increased bilirubin (9%), constipation (8%), decreased appetite (6%), and diarrhea (6%). Serious AEs at least possibly related to ensituximab occurred in 4 patients and included anemia, nausea, increased bilirubin, and hypoxia. No patients discontinued treatment due to drug-related AEs. Conclusions: Ensituximab was well tolerated and demonstrated modest antitumor activity in patients with heavily pretreated refractory colorectal cancer.

Background Regorafenib is an oral multikinase inhibitor targeting angiogenesis, oncogenesis, and cancer proliferation/metastasis. This study evaluated the efficacy of regorafenib in refractory biliary tract cancer (BTC) in a multi-institutional phase 2 study. Methods Patients with BTC who progressed on at least 1 line of systemic therapy received regorafenib at 160 mg daily for 21 days on and 7 days off. The primary endpoint was 6-month overall survival (OS), and the secondary endpoints were median OS, progression-free survival (PFS), and objective response rates. Pretreatment plasma was collected for cytokine evaluation. Results A total of 39 patients were enrolled, and 33 were evaluable for efficacy. The median PFS and OS were 3.7 and 5.4 months, respectively, with survival rates of 46.2% at 6 months, 35.9% at 12 months, and 25.6% at 18 months for the intention-to-treat population. For the 33 evaluable patients who received regorafenib for at least 3 weeks, the median PFS and OS were 3.9 and 6.7 months, respectively, with survival rates of 51.5% at 6 months, 39.4% at 12 months, and 27.3% at 18 months. The objective response rate was 9.1%, and the disease control rate was 63.6%. Twenty-eight patients (71.8%) experienced grade 3/4 adverse events. Among the 23 cytokines analyzed, elevated baseline vascular endothelial growth factor D (VEGF-D) was associated with shorter PFS, whereas elevated baseline interleukin 6 (IL-6) and glycoprotein 130 (GP130) were associated with shorter OS. Conclusions Regorafenib demonstrated modest clinical efficacy in heavily pretreated patients with BTC. Further exploration of biomarkers is warranted to identify a group of patients with BTC who may benefit from regorafenib.

Background The rationale for the evaluation of trametinib in advanced biliary cancer (BC) is based on the presence of mitogen-activated protein kinase alterations and on earlier promising results with MEK inhibitors in BC. Methods Patients with histologically proven BC who progressed on gemcitabine/platinum were randomised to trametinib daily (arm 1) versus fluoropyrimidine therapy (infusional 5-fluorouracil or oral capecitabine, arm 2). The primary end-point was overall survival (OS). Secondary end-points included progression free survival (PFS) and response rate. A planned interim futility analysis of objective response was performed on the first 14 patients registered to the trametinib arm. Results The study was stopped early based on the lack of measurable response in the trametinib arm. A total of 44 eligible patients were randomised (24 patients in arm 1 and 20 patients in arm 2). Median age was 62 years and the primary sites of tumour were cholangiocarcinoma (68%) and gallbladder (32%). The overall response rate was 8% (95% CI 0%–19%) in arm 1 versus 10% (95% CI 0%–23%) in arm 2 (p > .99) Median OS was 4.3 months for arm 1 and 6.6 months for arm 2. The median PFS was 1.4 months for arm 1 and 3.3 months for arm 2. Conclusions This is the first prospective randomised study of a targeted agent versus chemotherapy for the second-line treatment of BC. In this unselected population, the interim analysis result of unlikely benefit with trametinib resulted in early closure.

Gastric cancer is the sixth most common cancer and is known to be the fifth-leading cause of cancer-related deaths globally in 2018. Systemic therapy remains the only curative option in advanced gastric carcinoma with the primary goal of improving the Health-related Quality of Life (HRQoL) (including palliation of symptoms such as dysphagia) and prolonging overall survival. Recently, ramucirumab is approved by the United States Food and Drug Administration (US-FDA) as a second-line agent either as monotherapy or in combination with paclitaxel in advanced or metastatic gastric and gastro-esophageal junction adenocarcinoma patients who have progressed on prior treatment with fluoropyrimidine or platinum containing chemotherapy. HRQoL is a subjective term that typically constitutes four components - psychological, social, occupational and physical well being. This has been evaluated as secondary endpoint in the pivotal Phase III trials with ramucirumab. HRQoL measurement can potentially provide additional information for clinical decision making beyond that of traditional medical outcomes. The present work is primarily focused on discussing HRQoL in gastric cancer patients and the impact of ramucirumab on the HRQoL in the patients with advanced gastric cancer. We also summarized the studies that evaluated the benefits of systemic therapies on HRQoL in advanced gastric cancer.

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide with no clinically confirmed oncogenic driver. Although preclinical studies implicate the FGF19 receptor FGFR4 in hepatocarcinogenesis, the dependence of human cancer on FGFR4 has not been demonstrated. Fisogatinib (BLU-554) is a potent and selective inhibitor of FGFR4 and demonstrates clinical benefit and tumor regression in patients with HCC with aberrant FGF19 expression. Mutations were identified in the gatekeeper and hinge-1 residues in the kinase domain of FGFR4 upon disease progression in 2 patients treated with fisogatinib, which were confirmed to mediate resistance in vitro and in vivo. A gatekeeper-agnostic, pan-FGFR inhibitor decreased HCC xenograft growth in the presence of these mutations, demonstrating continued FGF19–FGFR4 pathway dependence. These results validate FGFR4 as an oncogenic driver and warrant further therapeutic targeting of this kinase in the clinic. Significance: Our study is the first to demonstrate on-target FGFR4 kinase domain mutations as a mechanism of acquired clinical resistance to targeted therapy. This further establishes FGF19–FGFR4 pathway activation as an oncogenic driver. These findings support further investigation of fisogatinib in HCC and inform the profile of potential next-generation inhibitors. See related commentary by Subbiah and Pal, p. 1646. This article is highlighted in the In This Issue feature, p. 1631

Outcomes for patients with advanced hepatocellular carcinoma (HCC) remain poor despite recent progress in drug development. Emerging data implicate FGF19 as a potential HCC driver, suggesting its receptor, FGFR4, as a novel therapeutic target. We evaluated fisogatinib (BLU-554), a highly potent and selective oral FGFR4 inhibitor, in a phase I dose-escalation/dose-expansion study in advanced HCC using FGF19 expression measured by IHC as a biomarker for pathway activation. For dose escalation, 25 patients received 140 to 900 mg fisogatinib once daily; the maximum tolerated dose (600 mg once daily) was expanded in 81 patients. Fisogatinib was well tolerated; most adverse events were manageable, grade 1/2 gastrointestinal events, primarily diarrhea, nausea, and vomiting. Across doses, the overall response rate was 17% in FGF19-positive patients [median duration of response: 5.3 months (95% CI, 3.7–not reached)] and 0% in FGF19-negative patients. These results validate FGFR4 as a targetable driver in FGF19-positive advanced HCC. Significance: Fisogatinib elicited clinical responses in patients with tumor FGF19 overexpression in advanced HCC. These results validate the oncogenic driver role of the FGFR4 pathway in HCC and the use of FGF19 as a biomarker for patient selection. See related commentary by Subbiah and Pal, p. 1646. This article is highlighted in the In This Issue feature, p. 1631

Aims The histone deacetylase inhibitor belinostat has activity in various cancers. Because belinostat is metabolized by the liver, reduced hepatic clearance could lead to excessive drug accumulation and increased toxicity. Safety data in patients with liver dysfunction are needed for this drug to reach its full potential in the clinic. Methods We performed a phase 1 trial to determine the safety, maximum tolerated dose (MTD) and pharmacokinetics of belinostat in patients with advanced cancer and varying degrees of liver dysfunction. Results Seventy-two patients were enrolled and divided into cohorts based on liver function. In patients with mild dysfunction, the MTD was the same as the recommended phase 2 dose (1000 mg/m2 /day). Belinostat was well tolerated in patients with moderate and severe liver dysfunction, although the trial was closed before the MTD in these cohorts could be determined. The mean clearance of belinostat was 661 mL/min/m2 in patients with normal liver function, compared to 542, 505 and 444 mL/min/m2 in patients with mild, moderate and severe hepatic dysfunction. Although this trial was not designed to assess clinical activity, of the 47 patients evaluable for response, 13 patients (28%) experienced stable disease. Conclusion While a statistically significant difference in clearance indicates increased belinostat exposure with worsening liver function, no relationship was observed between belinostat exposure and toxicity. An assessment of belinostat metabolites revealed significant differences in metabolic pathway capability in patients with differing levels of liver dysfunction. Further studies are needed to establish formal dosing guidelines in this patient population.

Hepatocellular carcinoma (HCC) accounts for about 90% of all primary liver cancers and is the second leading cause of cancer-related deaths worldwide. The hypervascular nature of most HCC tumors underlines the importance of angiogenesis in the pathobiology of these tumors. Several angiogenic pathways have been identified as being dysregulated in HCC, suggesting they may be involved in the development and pathogenesis of HCC. These data provide practical targets for systemic treatments such as those targeting the vascular endothelial growth factor receptor and its ligand. However, the clinical relevance of other more recently identified angiogenic pathways in HCC pathogenesis or treatment remains unclear. Research into molecular profiles and validation of prognostic or predictive biomarkers will be required to identify the patient subsets most likely to experience meaningful benefit from this important class of agents.

Aims: To compare the efficacy of nivolumab 1 mg/kg + ipilimumab 3 mg/kg with regorafenib 160 mg, cabozantinib 60 mg and nivolumab 3 mg/kg monotherapy for second-line treatment of advanced hepatocellular carcinoma. Materials & methods: Indirect comparison using network meta-analysis and propensity score weighting. Results: Nivolumab 1 mg/kg + ipilimumab 3 mg/kg had significantly higher objective response rate (median 31.2% [95% credible interval: 19.6–44.5%]) than cabozantinib (4.2% [2.0–6.5%]) and regorafenib (4.8% [1.1–8.3%]), and significantly longer overall survival (cabozantinib: hazard ratio: 0.46 [95% credible interval: 0.27–0.79]; regorafenib: 0.56 [0.32–0.97]). Nivolumab 1 mg/kg + ipilimumab 3 mg/kg had significantly better objective response rate (difference 21.0% [4.5–37.5%]) and overall survival (hazard ratio: 0.58 [0.35–0.96]) than nivolumab monotherapy. Conclusion: Nivolumab 1 mg/kg + ipilimumab 3 mg/kg had a superior efficacy versus cabozantinib 60 mg, regorafenib 160 mg and nivolumab 3 mg/kg monotherapy as second-line therapy for advanced hepatocellular carcinoma.

PROteolysis Targeting Chimeras (PROTACs) are a family of heterobifunctional small molecules that specifically target cellular proteins for degradation. Given that their mode of action is distinct from that of small-molecule inhibitors widely used in clinical practice, PROTACs have the potential to improve current cancer therapies. Multiple studies have suggested that PROTACs exhibit enhanced pharmacodynamics and reduced toxicity both in vitro and in vivo compared to clinically relevant small-molecule kinase inhibitors. In addition, PROTACs have been reported to be less prone to mutation-mediated drug resistance in specific disease settings. Since its development in 2001, the field of targeted protein degradation, in which PROTACs are used, has expanded rapidly. However, earlier studies focused on the advancement of the technology itself, while preclinical and clinical data on the disease-modifying effect of PROTACs have only recently been reported. As preclinical and clinical evidence accumulates, the efficacy of PROTACs as targeted therapeutics-distinct from that of small-molecule kinase inhibitors-suggests potential translational benefit in the clinical setting. In this short review, we aim to describe translational potentials of PROTACs. We offer our perspectives as practicing oncologists on the preclinical and clinical data on PROTACs as novel therapeutics for both solid and hematological malignancies.

Aim: Genomic-based risk stratification to personalize radiation dose in rectal cancer. Patients & methods: We modeled genomic-based radiation dose response using the previously validated radiosensitivity index (RSI) and the clinically actionable genomic-adjusted radiation dose. Results: RSI of rectal cancer ranged from 0.19 to 0.81 in a bimodal distribution. A pathologic complete response rate of 21% was achieved in tumors with an RSI

IMPORTANCE: Currently, there is no established second-line systemic treatment for biliary tract cancer (BTC). Preclinical data have demonstrated that the presence of tumor-infiltrating CD8 T cells and programmed cell death 1 ligand 1–expressing tumor cells in the tumor microenvironment of BTC supports the rationale of using programmed cell death 1 protein blockade immunotherapy in BTC. OBJECTIVE: To evaluate anticancer activity of nivolumab in patients with advanced refractory BTC. DESIGN, SETTING, AND PARTICIPANTS: In this single-group, multicenter phase 2 study of nivolumab, 54 patients with histologically confirmed BTC whose disease progressed while undergoing treatment with at least 1 line but no more than 3 lines of systemic therapy were enrolled between October 5, 2016, and December 26, 2018. Analysis was performed on an intention-to-treat basis. INTERVENTIONS: Nivolumab, 240 mg, was delivered intravenously every 2 weeks for 16 weeks, and then 480 mg was delivered intravenously every 4 weeks until disease progression or unacceptable toxic effects occurred. MAIN OUTCOMES AND MEASURES: The primary end point was investigator-assessed objective response rate, and the secondary end points were progression-free survival, overall survival, and incidence of adverse events. RESULTS: A total of 54 patients (27 men and 27 women; median age, 65 years [range, 28-86 years]) enrolled, and 46 (22 men and 24 women; median age, 65 years [range, 28-86 years]) were examined for objective response with radiologic imaging. The investigator-assessed objective response rate was 22% (10 of 46), including 1 unconfirmed partial response, with a disease control rate of 59% (27 of 46). Central independent review found an objective response rate of 11% (5 of 46), including 1 unconfirmed partial response, with a disease control rate of 50% (23 of 46). All patients who responded to treated (hereafter referred to as responders) had mismatch repair protein–proficient tumors. The median duration of investigator-assessed response was not reached, with a median follow-up of 12.4 months. Among the intention-to-treat population, median progression-free survival was 3.68 months (95% CI, 2.30-5.69 months) and median overall survival was 14.24 months (95% CI, 5.98 months to not reached). Programmed cell death 1 ligand 1 expression in tumors was associated with prolonged progression-free survival (hazard ratio, 0.23; 95% CI, 0.10-0.51; P

Background US health care is increasingly defined by over expenditure and inefficiency. Optimizing patient follow-up is critical, especially in cancers treated with high control rates. To optimize patient care, this study assessed time to disease recurrence or toxicity in patients with anal carcinoma. Materials and methods In total, 140 patients with biopsy-proven, nonmetastatic anal carcinoma, treated with chemoradiation utilizing intensity-modulated radiation therapy, were identified from our institutional database. This retrospective study evaluated local recurrence (LR), distant metastasis (DM), overall survival (OS), and late ≥grade 3 toxicity (LG3T). Patients were followed posttreatment every 3 months for 2 years, every 6 months in years 3 to 5, then yearly thereafter per NCCN recommendations. Results The median age and follow-up was 58 years and 27 months, respectively. Patients were categorized into high (n=61; 44%) and low (n=77; 55%) risk groups based on stage. The 2-year LC, DMFS, and OS were 93%, 94%, and 89% and 5-year LC, DMFS, OS were 92%, 87%, and 85%, respectively. Overall, there were 29 events (9 LR, 11 DM, and 9 LG3T), with 62% of events occurring within year 1 and 79% within 2 years. Stratified by event type, at 2 years 89% of LR, 64% of DM, and 89% LG3T were identified. At the remaining follow-up points, the event incidence rate was 1.3%. Conclusion With the majority of recurrences/toxicities occurring within the first 2 years, a reduction in follow-up during years 3 to 5 may provide adequate surveillance. Revisions of the current recommendations could maximize resources while improving patient quality of life.

Introduction Innovative biomarkers to predict treatment response in rectal cancer would be helpful in optimizing personalized treatment approaches. In this study, we aimed to develop and validate a CT-based radiomic imaging biomarker to predict pathological response. Methods We used two independent cohorts of rectal cancer patients to develop and validate a CT-based radiomic imaging biomarker predictive of treatment response. A total of 91 rectal cancer cases treated from 2009 to 2018 were assessed for the tumour regression grade (TRG) (0 = pathological complete response, pCR; 1 = moderate response; 2 = partial response; 3 = poor response). Exploratory analysis was performed by combining pre-treatment non-contrast CT images and patterns of TRG. The models built from the training cohort were further assessed using the independent validation cohort. Results The patterns of pathological response in training and validation groups were TRG 0 (n = 14, 23.3%; n = 6, 19.4%), 1 (n = 31, 51.7%; n = 15, 48.4%), 2 (n = 12, 20.0%; n = 7, 22.6%) and 3 (n = 3, 5.0%; n = 3, 9.7%), respectively. Separate predictive models were built and analysed from CT features for pathological response. For pathological response prediction, the model including 8 radiomic features by random forest method resulted in 83.9% accuracy in predicting TRG 0 vs TRG 1-3 in validation. Conclusion The pre-treatment CT-based radiomic signatures were developed and validated in two independent cohorts. This imaging biomarker provided a promising way to predict pCR and select patients for non-operative management.

Background Regorafenib, a multikinase inhibitor that inhibits angiogenesis, growth, and proliferation, prolongs survival as monotherapy in patients with refractory colorectal cancer. This international, double-blind, placebo-controlled, multicenter trial assessed the efficacy of regorafenib with folinic acid, fluorouracil, and irinotecan (FOLFIRI) as a second-line treatment for metastatic colorectal cancer. Methods Patients with metastatic colorectal cancer who progressed on first-line oxaliplatin and fluoropyrimidine enrolled at 45 sites in the United States and Ireland. Patients, stratified by prior bevacizumab use, were randomized 2:1 to regorafenib or placebo. The treatment consisted of FOLFIRI on days 1 and 2 and days 15 and 16 with 160 mg of regorafenib or placebo on days 4 to 10 and days 18 to 24 of every 28-day cycle. Crossover was not allowed. The primary endpoint was progression-free survival (PFS). Under the assumption of a 75% event rate, 180 patients were required for 135 events to achieve 90% power to detect a hazard ratio (HR) of 0.65 with a 1-sided α value of .1. Results One hundred eighty-one patients were randomized (120 to regorafenib-FOLFIRI and 61 to placebo-FOLFIRI) with a median age of 62 years. Among these, 117 (65%) received prior bevacizumab or aflibercept. PFS was longer with regorafenib-FOLFIRI than placebo-FOLFIRI (median, 6.1 vs 5.3 months; HR, 0.73; 95% confidence interval [CI], 0.53-1.01; log-rank P = .056). The median overall survival was not longer (HR, 1.01; 95% CI, 0.71-1.44). The response rate was higher with regorafenib-FOLFIRI (34%; 95% CI, 25%-44%) than placebo-FOLFIRI (21%; 95% CI, 11%-33%; P = .07). Grade 3/4 adverse events with a >5% absolute increase from regorafenib included diarrhea, neutropenia, febrile neutropenia, hypophosphatemia, and hypertension. Conclusions The addition of regorafenib to FOLFIRI as second-line therapy for metastatic colorectal cancer only modestly prolonged PFS over FOLFIRI alone. Cancer 2018. © 2018 American Cancer Society.

Objectives Early-phase clinical trials play a pivotal role in drug development. However, limited data are available on outcomes of gastrointestinal (GI) cancer patients enrolled in phase I clinical trials. Here, we evaluated the characteristics associated with survival in GI cancer patients participating in phase I clinical trials and attempted to validate previously established prognostic models. Materials and methods All consecutive patients with advanced GI tumors who participated in phase I clinical trials at our institution from January 2007 to December 2013 and received at least 1 dose of the study drug were included. Cox regression models were used to estimate multivariable-adjusted hazard ratio (HR) and 95% confidence interval. Results In 243 study patients (median age, 62 y [range, 26 to 82 y]; 55% male), treatment included chemotherapy only (14%), targeted therapy (41%), chemotherapy+targeted therapy (42%), and others (2%) for the following disease types: pancreatic (42%), colorectal (34%), gastroesophageal (10%), hepatobiliary (13%), and others (2%). Response rate was 4%, with 38% achieving stable disease and 42% having progressive disease. Median survival was 5.8 months (range, 0.2 to 52.4 mo). Our multivariable Cox regression analyses included the following as predictors of survival: Eastern Cooperative Oncology Group performance score ≥1 (HR=1.76), prior systemic therapies ≥2 (HR=1.63), lactate dehydrogenase >618 IU/L (HR=1.85), sodium >135 mmol/L (HR=0.46), and white blood count >6×10/L (HR=1.5). Our data set was consistent with previous prognostic scores. Conclusions This is the largest study to assess clinical outcomes in this patient population. Phase I trials provide clinical benefit to patients with advanced GI malignancies and should be recommended as a treatment option in appropriate patients.

Background: Copanlisib is a pan-class I phosphatidylinositol 3-kinase (PI3K) inhibitor with predominant PI3K-α/δ activity that has demonstrated clinical activity and manageable safety when administered as monotherapy in a phase II study. Combination therapy may overcome compensatory signalling that could occur with PI3K pathway inhibition, resulting in enhanced inhibitory activity, and preclinical studies of copanlisib with gemcitabine have demonstrated potent anti-tumour activity in vivo. Methods: A phase I, open-label, dose-escalation study to evaluate the safety, tolerability and recommended phase II dose (RP2D) of copanlisib with gemcitabine or with cisplatin plus gemcitabine (CisGem) in patients with advanced malignancies, including an expansion cohort in patients with biliary tract cancer (BTC) at the RP2D of copanlisib plus CisGem. Copanlisib and gemcitabine were administered on days 1, 8 and 15 of a 28-day cycle; maximum tolerated dose (MTD) and RP2D of copanlisib were determined. Copanlisib plus CisGem was administered on days 1 and 8 of a 21-day cycle; pharmacokinetics and biomarkers were assessed. Results: Fifty patients received treatment as follows: dose-escalation cohorts, n=16; copanlisib plus CisGem cohort, n=14; and BTC expansion cohort, n=20. Copanlisib 0.8 mg kg−1 plus gemcitabine was the MTD and RP2D for both combinations. Common treatment-emergent adverse events included nausea (86%), hyperglycaemia (80%) and decreased platelet count (80%). Copanlisib exposure displayed a dose-proportional increase. No differences were observed upon co-administration of CisGem. Response rates were as follows: copanlisib plus gemcitabine, 6.3% (one partial response in a patient with peritoneal carcinoma); copanlisib plus CisGem, 12% (one complete response and three partial responses all in patients with BTC (response rate 17.4% in patients with BTC)). Mutations were detected in PIK3CA (1 out of 43), KRAS (10 out of 43) and BRAF (2 out of 22), with phosphate and tensin homologue protein loss in 41% (12 out of 29). Conclusions: Copanlisib plus CisGem demonstrated a manageable safety profile, favourable pharmacokinetics, and potentially promising clinical response.

Background: Although squamous cell anal carcinomas are relatively rare, their incidence has been increasing steadily. Because of the limited data, treatment of metastatic disease is a major therapeutic challenge. In this study, we report the safety and efficacy of epidermal growth factor receptor (EGFR) inhibitors in patients with advanced squamous cell anal carcinomas. Method: A retrospective analysis was conducted using the Moffitt Cancer Tumor Registry from January 2009 to January 2014. Eligible patients had diagnosis of advanced squamous cell anal carcinomas and received an EGFR inhibitor as part of their treatment. Result: A total of 13 patients were identified for analysis. All of them received concurrent chemoradiation as initial treatment and subsequently had recurrence. Five patients received single agent cetuximab or panitumumab, and the others received cetuximab or panitumumab with irinotecan or FOLFIRI. The objective response rate was 30.8% including 1 complete response, and the disease control rate was 46.2%. With a median follow-up of 9.6 months, the median progression-free survival and median overall survival were 4.4 months and 11.4 months, respectively. Conclusion: Our analysis suggests that EGFR inhibitors have potential efficacy and are reasonably well tolerated in patients with squamous cell anal carcinomas. These findings warrant further evaluation in a large prospective trial.

Purpose To evaluate the safety and efficacy of partial splenic embolization (PSE) in cancer patients with different etiologies of splenomegaly/hypersplenism. Materials and Methods The medical records of 35 cancer patients who underwent 39 PSE procedures were analyzed. The splenomegaly/hypersplenism was due to chemotherapy (n = 17), portal hypertension (n = 10), or hematologic malignancy (n = 8). After the first 11 PSEs, celiac plexus neurolysis, corticosteroids, and non-steroid anti-inflammatory drugs (NSAIDs) were included in the post-procedural management. Results PSE led to 59 ± 16% (mean ± standard deviation) splenic infarcts. The infarct volume per 1 mL 300–500 μm tris-acryl gelatin microspheres was not significantly different between the chemotherapy-induced group (264 ± 89 cm3) and the portal hypertension group (285 ± 139 cm3) but was significantly higher in the hematology group (582 ± 345 cm3). Platelet count increased from 65.7 ± 19.7 k/μl to a peak platelet count of 221 ± 83 k/μl at 2 weeks after PSE. Patients with a follow-up period of more than 1 year had the most recent platelet count of 174 ± 113 k/μl. Platelet count increase was significantly higher in the chemotherapy-induced group than the portal hypertension group. Adding celiac plexus neurolysis, corticosteroids, and NSAIDs to the post-procedural management resulted in a decreased rate of major complications from 73% to 46% and a decrease in the rate of moderate or severe pain from 92% to 20%. Conclusions PSE improved platelet counts in cancer patients despite different etiologies of splenomegaly. The addition of celiac plexus neurolysis, corticosteroids, and NSAIDS to the post-PSE treatment protocol reduced complications. Data from this study could help to predict the amount of 300–500 μm tris-acryl gelatin microspheres required to achieve a planned infarct size.

4078 Background: REG, a multikinase inhibitor, and PEMBRO, an anti-PD-1 mAb, are approved as monotherapies in advanced HCC after progression on sorafenib. This phase 1b dose-finding study investigated first-line REG plus PEMBRO in advanced HCC. Methods: Patients (pts) in the first cohort received a starting REG dose of 120 mg/day orally for 3 weeks (wks) on/1 wk off, which could be escalated (160 mg) or reduced (80 mg) in later cohorts, plus a fixed dose of PEMBRO 200 mg IV every 3 wks. Due to a high dose modification rate in the REG 120 mg cohort, an exploratory REG 80 mg cohort was introduced. Primary objective was safety and tolerability; secondary aims were to assess the maximum tolerated dose (MTD), recommended phase 2 dose, and anti-tumor activity. Results: 35 pts started on REG 120 mg/day and 22 on REG 80 mg/day. Median age was 66 yrs (range 29–81), 84% of pts were male, 70%/30% had ECOG PS 0/1, 26%/74% were BCLC stage B/C, 100% were C–P A, 46% had extrahepatic spread, and 32% had macrovascular invasion. MTD of REG was 120 mg/day. Grade (Gr) 3/4 treatment-emergent adverse events (TEAE) occurred in 86% of pts on REG 120 mg and 50% on REG 80 mg (Table). Most common Gr 3/4 TEAE for REG 120 mg/80 mg were AST increased (23%/9%), lipase increased (20%/5%), ALT increased (17%/9%), and hypertension (17%/9%). TEAE led to REG/PEMBRO dose reductions or interruptions in 71%/57% of pts on REG 120 mg and 59%/45% on REG 80 mg. Median treatment duration (range) was 3.0 months (mo; 0.2–20.5) for REG 120 mg and 3.5 mo (0.03–24.4) for PEMBRO, and 3.5 mo (0.7–10.8) for REG 80 mg and 3.5 mo (0.8–11.3) for PEMBRO. Of 32 evaluable pts on REG 120 mg, 10 (31%) had a partial response (PR) and 18 (56%) had stable disease (SD); disease control rate (DCR) was 88% (RECIST v1.1). Of 22 pts on REG 80 mg, 4 (18%) had a PR and 16 (73%) had SD; DCR was 91%. As of 17 Dec 2020, 16 pts remain on treatment (REG 120 mg n = 5; REG 80 mg n = 11); median follow up was 11.7 mo and 6.9 mo, respectively. REG pharmacokinetic exposure was as expected for 80 mg and 120 mg doses. Flow cytometry analysis of sequential peripheral blood showed changes in subsets of T-cells and monocytes, which may contribute to clinical benefit. Conclusions: First-line REG plus PEMBRO in advanced HCC showed no new safety signals and encouraging anti-tumor activity (DCR ̃90%). The REG 80 mg cohort appeared to have lower rates of dose reductions and interruptions due to TEAE vs REG 120 mg. Efficacy data for the REG 80 mg cohort are preliminary due to short follow-up. Clinical trial information: NCT03347292. [Table: see text]

3050 Background: TAK-164 is a second-generation ADC comprising a human IgG1 monoclonal antibody targeting GCC conjugated to a DNA-damaging alkylating agent by a peptide linker. TAK-164 demonstrated cytotoxic and antitumor activity in GCC-expressing cells and xenograft mouse models. This first-in-human study investigated the safety, pharmacokinetics (PK), and preliminary efficacy of TAK-164. Methods: Adult pts with GCC-positive, advanced/metastatic GI cancers received TAK-164 intravenously on day 1 of a 21-day cycle (Q3W). Dose escalation proceeded based on cycle 1 safety data via a Bayesian model of modified toxicity probability interval starting at 0.004 mg/kg. Results: Thirty-one pts were enrolled. Median age was 58 years (range 32–72), 58.1% of pts were female and 64.5% had colon carcinoma. The median number of prior lines of therapy was 4 (range 2–9). TAK-164 was given at 0.004 (n = 1), 0.008 (n = 1), 0.016 (n = 1), 0.032 (n = 5), 0.064 (n = 7), 0.12 (n = 7), 0.16 (n = 2), 0.19 (n = 3), 0.25 (n = 3) and 0.32 mg/kg (n = 1). No pts had dose-limiting toxicities (DLT) in cycle 1 up to 0.32 mg/kg. Three pts had adverse events (AEs) after cycle 1 considered to be DLTs: 1 pt receiving 0.19 mg/kg (grade 3 pyrexia and grade 5 hepatic failure) and 2 pts receiving 0.25 mg/kg (1 pt had grade 3 nausea, and grade 4 platelet count decrease and neutrophil count decrease; 1 pt had grade 4 hepatic failure and grade 4 platelet count decrease). Dosing was capped at 0.19 mg/kg due to hepatic toxicity and the recommended phase 2 dose (RP2D) was determined as 0.064 mg/kg based on safety and tolerability beyond cycle 1. Overall, pts received a median of 2 (range 1–8) treatment cycles. TAK-164-related treatment-emergent AEs (TEAEs) reported in 77.4% of pts included platelet count decrease (58.1%), fatigue (38.7%), and anemia (32.3%). TAK-164-related grade ≥3 TEAEs reported in 32.3% of pts included platelet count decrease (12.9%), alanine aminotransferase increase, aspartate aminotransferase increase, fatigue, and anemia (all 9.7%). Three pts discontinued due to TAK-164-related TEAEs. There was a dose-dependent increase in TAK-164 maximum plasma concentration and exposure over the range 0.016–0.32 mg/kg, with no meaningful accumulation in PK with repeat Q3W dosing. One pt receiving TAK-164 0.19 mg/kg showed γH2AX induction via immunohistochemistry in a post-treatment biopsy, demonstrating target engagement. One pt with low baseline GCC expression who received 5 cycles of TAK-164 0.008 mg/kg had an unconfirmed partial response at cycle 4; 11 of 25 (44.0%) evaluable pts had a best overall response of stable disease. Conclusions: TAK-164 appeared to have a manageable safety profile up to 0.064 mg/kg in pts with advanced GI cancers; hepatic toxicity was identified as a potential risk. The RP2D was determined as 0.064 mg/kg but was considered insufficient to derive significant clinical benefit. Clinical trial information: NCT03449030.

e16266 Background: Pancreatic cancer is one of the deadliest malignancies, with a 5 year OS of around 3%. Up to 3% of unselected patients (pts) with (PDAC) have the BRCA 1/2 mutation, while up to 15% possess HRD (ARID1A, ATM, BAP1, BARD1, BRIP1, CHEK1/2, FANCA, PALB2, RAD50, RAD51). PARP inhibitors, like olaparib, demonstrate clinical benefit in metastatic PDAC with BRCA mutations (mBRCA) and may have a role in those with HRD. The objective of this study is to determine the role of PARP inhibition in PDAC with HRD. Methods: This was a retrospective chart review of metastatic PDAC pts with germline (g) or somatic (s) mBRCA or HRD who received olaparib. An analysis of PFS and OS was performed for PDAC pts with mBRCA vs. HRD. Results: Forty-six pts with metastatic pancreatic cancer were identified to have mBRCA (n = 13) or HRD (n = 23) and received olaparib in our database. Median age was 73 years for mBRCA and 66 years for HRD. Five pts received olaparib as maintenance therapy after disease control with platinum: 2 mBRCA and 3 HRD pts. Six pts with mBRCA and 7 pts with HRD were platinum naïve prior to olaparib. Zero pts with mBRCA and 3 pts with HRD received olaparib after disease progression on platinum. The median (med)PFS for mBRCA vs. HRD was 6.1 months vs. 2.8 months (HR 0.5, 95% CI: 0.2-1.1, p = 0.07). The medOS for mBRCA vs. HRD was 7.7 vs. 5.3 months (HR 0.7, 95% CI: 0.2-1.9, p = 0.4). Of those with mBRCA who received olaparib, prior cisplatin exposure (n = 8) vs. cisplatin naïve (n = 5) led to medPFS of 6.1 vs. 7.8 months (HR 1.8, 95% CI 0.5-6.7, p = 0.3) and medOS of 6.8 months vs. 9.5 months (HR 1.5, 95% 0.3-6.4, p = 0.6). Six pts with HRD including gCHEK2 c.407T > C, gCHEK2 c.1461+1 G > A, gPALB2 gain (exon 11), sFANCI p.N1252S, sATM p.V2716A, sARID1A Q944fs*14 were noted to have disease control of at least 3 months on olaparib. Only one of these pts received olaparib as maintenance therapy after platinum. The medPFS was 6.1 months and medOS was not reached. One pt with HRD (sFANCI N1252S) had progressive disease on platinum prior to olaparib, but had stable disease > 5 months with olaparib. Conclusions: Our study suggests olaparib may have anticancer activity in PDAC with certain HRD. In addition, olaparib may have a role outside maintenance therapy in PDAC with mBRCA. Prospective studies are needed to confirm these findings.

415 Background: Immune checkpoint inhibitors (ICI) have been approved in solid tumors with dMMR. However, only limited data are available for PDAC with dMMR given the rarity of dMMR in PDAC. We evaluated efficacy of ICIs in PDAC with dMMR. Methods: Retrospective clinical and pathologic data were collected for patients (pts) with pancreatic adenocarcinoma from May 2017 to June 2020 at Moffitt cancer center. Results: We identified 10 pts with dMMR PDAC. The median age was 64.5 years (range: 42-86) and 4 pts were male. 4 pts had resectable disease, 3 had locally advanced and 3 had metastatic disease at initial diagnosis. MSH6 deficiency (def) was found in 2 cases, PMS2 def in 2, MLH/PMS2 def in 5, and MSH2/MSH6 in 1. 7 pts were treated with ICIs. 3 pts had locally advanced and 4 had metastatic disease when they started ICIs. 5 received Pembrolizumab (pem), 1 received ipilimumab/ nivolumab (ipi/nivo), and 1 received pem then ipi/nivo after progressive disease (PD) on pem. The median number of prior lines of chemotherapy was 1 (range 0-2). 6 pts were evaluable, and 1 had rapid disease progression after 1 dose of pem. Among 6 evaluable pts, 3 had an objective response (1: complete response and 2: partial response), and 2 had stable disease (SD). Median progression-free survival was 8.2 mo, and median overall survival was not reached with median follow-up (FU) of 6.8 mo. The median duration of response was not reached with a median FU of 22.6 mo. The pt with CR remained disease-free for up to 22 months. The pt whose treatment was switched to ipi/nivo after PD on pem achieved SD > 4mo on ipi/nivo. While on immunotherapy, one patient with ipi/nivo developed immunotherapy associated rash requiring systemic steroids, and another on pem developed hypothyroidism requiring levothyroxine. Conclusions: This series suggest ICIs can provide durable clinical efficacy in pts with dMMR PDAC.

TPS358 Background: The anti–PD-L1 antibody ATEZO prevents PD-L1 from interacting with PD-1 and B7.1, thus reinvigorating antitumor T cell activity. Anti-VEGF BEV can increase dendritic cell maturation, enhance T cell infiltration, and reduce myeloid-derived suppressor cells and regulatory T-cells in tumors. This combination has been FDA approved for first-line treatment of advanced HCC based on the IMbrave 150 study. On the other hand, locoregional radiotherapy (e.g., Y90 TARE) enhances the diversity of the intratumoral T cell receptor repertoire. It is the standard of care for pts with intermediate-stage HCC (iHCC). Based on preclinical and clinical data, we hypothesize that the combination of Y90 TARE, BEV, and ATEZO induces synergistic tumor-killing. Methods: This is an open-label, multicenter, randomized phase II study of Y90 TARE and BEV plus ATEZO compared with Y90 TARE alone in pts with unresectable IHCC. The primary study objective is to assess and compare the progression-free survival (PFS) (per mRECIST 1.1) of pts in each arm. The main secondary objective is to determine the safety and tolerability (CTCAE v5) of TARE combined with ATEZO and BEV in pts with HCC. Exploratory objectives are to assess the role of the immunoscore and PD-L1 expression levels in the prediction of improved clinical outcome in pts receiving Y-90 TARE and BEV plus ATEZO; the composition of tumor-infiltrating immune cell subtypes in predicting response to a chosen therapy; how Y90 therapy affects the proportion of antigen-presenting cells in the tumor; and symptoms experienced by pts receiving TARE and BEV plus ATEZO treatment, using patient-reported outcomes. Eligible pts have either HCC that is not amenable to surgical resection, confirmed by pathology review, or at least BCLC stage B HCC outside of downstaging criteria. Other standard eligibility criteria apply. Pts must have a pretreatment liver biopsy taken and then be randomized 1:1 to TARE (Arm A) or TARE followed by ATEZO and BEV (Arm B). Pts will have TARE mapping during week (wk) 1 and TARE treatment during wk 2. In Arm B, pts will start BEV plus ATEZO 4 wks (±1 wk) after TARE treatment. Pts will have abdominal MRI or CT scans every 12 weeks, CT scans of the chest every 24 wks, and a second tumor biopsy at 4 wks. Disease progression will be captured by both RECIST 1.1 and mRECIST. We plan to assess the safety of TARE with BEV and ATEZO in the first 10 pts randomized to Arm B for two cycles. If there are no grade ≥ 3 unexpected toxicities possibly, probably or definitely related to combined TARE plus BEV plus ATEZO, the study will continue to accrue 128 pts in total. Pts will continue study treatment (Arm B) for a total of 24 months from initiation of TARE or until intolerable toxicity or disease progression occur, whichever is earlier. Enrollment began in September 2020. Clinical trial information: NCT04541173.

323 Background: In a phase Ib study, REG 120 mg/day plus PEMBRO for first-line treatment of advanced HCC showed no unexpected safety signals and encouraging anti-tumor activity. At the maximum tolerated dose (MTD) of REG (120 mg/day), approximately three-quarters of patients (pts) had a REG dose reduction or interruption due to a treatment-emergent adverse event (TEAE). Here, we present preliminary data for the REG 80 mg/day cohort. Methods: This is an ongoing, dose-finding study in pts who had no prior systemic therapy. In the first cohort, pts received REG 120 mg/day orally for 3 weeks on/1 week off plus PEMBRO 200 mg intravenously q 3 weeks. In later cohorts, the REG dose could be escalated (160 mg/day) or reduced (80 mg/day); the PEMBRO dose is fixed. The primary objective is safety and tolerability. Secondary objectives are to define the MTD and recommended phase II dose and assess anti-tumor activity. Results: By July 24, 2020, 16 pts were treated with REG 80 mg/day. Median age was 67 years (range 56–79), 25%/75% were Barcelona Clinic Liver Cancer stage B/C, 100% Child–Pugh A, and 69%/31% had Eastern Cooperative Oncology Group performance status 0/1. Grade (Gr) 3 TEAEs occurred in 8/16 pts (50%) and there were no Gr 4 TEAEs (Table); one pt experienced Gr 5 pneumonitis (not drug related). There were no reports of Gr 3 hand–foot skin reaction or Gr 3 maculopapular rash, and one report (6%) of Gr 3 rash. TEAEs led to a REG dose reduction or interruption in 50% of pts and to a PEMBRO dose interruption in 25% of pts. Median treatment duration (range) including pts ongoing was 4.1 months (0.4–7.1) for REG and 3.8 months (0.03–7.2) for PEMBRO. Of 13 evaluable pts, 2 (15%) had a partial response and 9 (69%) had stable disease (Response Evaluation Criteria in Solid Tumors v1.1); disease control rate was 85%. Conclusions: These preliminary results for the combination of REG 80 mg/day plus PEMBRO for first-line treatment of advanced HCC were consistent with the REG 120 mg/day cohort. The combination showed no unexpected safety signals and encouraging anti-tumor activity. Assessment of REG 80 mg/day plus PEMBRO is ongoing. Clinical trial information: NCT03347292. [Table: see text]

338 Background: Our previous phase II study demonstrated that nivolumab provides modest but durable clinical efficacy in patients (pts) with refractory biliary tract cancer (BTC), suggesting the significant clinical benefit of nivolumab in selected pts and identification of potential predictive biomarkers. Here, we report outcomes from the biomarker analysis. Methods: Pre-treatment tumor samples were obtained and assessed for immunohistochemistry (IHC) with PD-1 and PDL-1 antibodies, mRNA sequencing (RNAseq), and whole exome sequencing (WES). Clinical efficacy was correlated with the molecular analysis. Prior cisplatin exposure was reviewed to evaluate the impact of cisplatin on the tumor mutational burden (TMB) and clinical outcome. Results: Among 46 pts who had tumor response evaluation, 31 pts received cisplatin prior to nivolumab, and 15 were cisplatin-naive. Pre-treatment tumor samples were assessed for IHC (n = 42), RNAseq (n = 11), and WES (n = 11) based on tissue availability. There was no statistically significant correlation between prior cisplatin exposure and clinical outcome. Among 42 available tumor samples, 18 (43%) expressed PD-L1 positivity ( > 1%), which was associated with a statistically significant prolonged progression free survival (PFS). Median PFS was 10.4 months for PD-L1 positive vs 2.4 months for PD-L1 negative (HR 0.23, 95% CI 0.10-0.51; P < 0.001), while there was no statistically significant correlation between PD-1 expressing tumor infiltrating lymphocytes and clinical outcome. There was also no statistically significant difference in TMB of cisplatin-exposed (n = 8) vs. cisplatin-naïve tumor samples (n = 3) (9162, SD = 150 vs. 8898, SD = 806, p = 0.62). In comparing the group with prolonged disease control of at least 16 weeks (n = 4) to those with rapid disease progression (n = 7) who had mRNA sequencing performed, levels of AC005609.1, FAT3, TMEM151A, ADARB2, FAM153A were all significantly upregulated (p < 0.01), while levels of CLCA1, MUC2, IGHV3-43, SWORA6, and CRISP3 were all significantly downregulated (p < 0.01). Conclusions: Prior cisplatin exposure did not lead to statistically significant differences in clinical outcome or TMB in advanced BTC pts treated with nivolumab. However, PD-L1 expression > 1% correlated with improved PFS, and variations in level of certain mRNA sequences were noted when comparing pts who had rapid disease progression vs. prolonged disease control with nivolumab. This suggests that BTC pts with positive PD-L1 expression and a particular mRNA profile may have a favorable response to nivolumab. Further studies are needed to confirm these findings. Clinical trial information: NCT02829918.

341 Background: A decrease in post-tx AFP may be associated with improved outcomes in clinical trials. However, the impact of AFP reduction after initiation of a first-line (1L) tyrosine kinase inhibitor (TKI) therapy on outcomes is unclear among pts with aHCC treated in routine clinical practice. Methods: This analysis utilized data from the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database and included pts with aHCC with ≥2 visits between 1/1/2011-7/31/2019 who received 1L TKI. Pts with a baseline serum AFP value (closest to 1L initiation within -30 to +7 days) and a post-tx AFP value (closest to 8 weeks after 1L initiation within ±2 weeks) were included. Post-tx AFP reduction was defined as a ≥20% decrease from baseline AFP, and no reduction as a

Background The incidence and outcomes of patients with colorectal cancer (CRC) varies by age. Younger patients tend to have sporadic cancers that are not detected by screening and worse survival. To understand whether genetic differences exist between age cohorts, the authors sought to characterize unique genetic alterations in patients with CRC. Methods In total, 283 patients who were diagnosed with sporadic CRC between 1998 and 2010 were identified and divided by age into 2 cohorts-ages ≤45 years (the younger cohort) and ≥65 years (the older cohort)-and targeted exome sequencing was performed. The Fisher exact test was used to detect differences in mutation frequencies between the 2 groups. Whole exome sequencing was performed on 21 additional younger patient samples for validation. Findings were confirmed in The Cancer Genome Atlas CRC data set. Results In total, 246 samples were included for final analysis (195 from the older cohort and 51 from the younger cohort). Mutations in the FBXW7 gene were more common in the younger cohort (27.5% vs 9.7%; P = .0022) as were mutations in the proofreading domain of polymerase e catalytic subunit (POLE) (9.8% vs 1%; P = .0048). There were similar mutation rates between cohorts with regard to TP53 (64.7% vs 61.5%), KRAS (43.1% vs 46.2%), and APC (60.8% vs 73.8%). BRAF mutations were numerically more common in the older cohort, although the difference did not reach statistical significance (2% vs 9.7%; P = .082). Conclusions In this retrospective study, a unique genetic profile was identified for younger patients who have CRC compared with patients who are diagnosed at an older age. These findings should be validated in a larger study and could have an impact on future screening and treatment modalities for younger patients with CRC. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2828-2835. © 2016 American Cancer Society.

Introduction Ampullary adenocarcinoma (AAC) is a rare neoplasm. We sought to determine the clinicopathologic factors contributing to the overall survival (OS) and recurrence-free (RFS) survival. Methods Patients (pts) with resected AAC were identified from 1996 to 2015 and reviewed for clinicopathologic factors and correlated with outcome. Results We identified and evaluated 106 pts diagnosed with AAC. The median age was 70.2 years (range 41–86) and 60 (56.6%) were male. Overall, 105 pts (99.1%) had a pancreaticoduodenectomy. An R0 resection was achieved in 101 (95%) pts. Median follow-up was 19 months with a median OS of 49.3 months. Lymph node metastasis and poorly differentiated tumors adversely affected OS on multivariate analysis (MVA). Twenty patients (18.9%) developed recurrence. The median RFS was 27 months. RFS was adversely affected by lymph node count and metastasis, tumor differentiation, and histological subtype on MVA. Survival was not affected by the addition of adjuvant therapy. Retrieval of ≤12 lymph nodes and lymph node ratio ≥0.10 resulted in worse OS on Kaplan–Meier analysis. Conclusions Our data show retrieval of ≤12 nodes, involvement of nodes with AAC, moderately or poorly differentiated tumors, and pancreaticobiliary subtype adversely affected survival, while the use of adjuvant therapy demonstrated no significant benefit. J. Surg. Oncol. © 2016 Wiley Periodicals, Inc.

Purpose: Targeting dual/multiple angiogenesis receptor has been shown to augment tumor response. Lenvatinib, a multikinase inhibitor aimed towards FGFR/ PDGFR/ KIT/RET has shown potent antitumor activity in preclinical models. This study aims to understand the effectiveness and safety of lenvatinib and capecitabine combined with radiation in patients with locally advanced rectal cancer (LARC). Methods: Patients with MRI or endoscopic ultrasound confirmed stage II or stage III rectal cancer were enrolled in 3 cohorts. All cohorts received standard dose 850 mg/m2 PO BID of capecitabine and external beam radiation (180 cGY) on day 1-5 weekly for 5 ½ to 6 weeks. Oral lenvatinib was administered in dose escalation manner in 3 cohorts of 3 patients per dose level (DL), with an expansion cohort at the MTD [cohort 1:14 mg daily; cohort 2: 20 mg daily; cohort 3:24 mg daily]. At the MTD dose, 10 additional patients were added to further evaluate safety and efficacy. Results: Twenty patients were enrolled and received at least 1 dose of study drug. One patient was deemed not eligible due to having stage IV disease at the time of diagnosis and is only reviewed for toxicity. 3/19 patients had stage II and 16/19 had stage III cancer at time of enrollment. 73.6% (14/19) patients enrolled were male and 26.4% (5/19) were female. The median age was 55 years (42,73). There was no noted dose limited toxicity at maximum tolerated dose (24 mg) of lenvatinib. There were no grade 4 adverse events. The most common grade 3 toxicities were hypertension observed in 15% (3/20) and lymphopenia in 15% (3/20) patients. Other grade 3 toxicities included rectal pain, hyponatremia, lymphopenia, leukocytosis and transaminitis, each noted in 5% (1/20) patients respectively. 19 patients underwent surgery in 6-10 weeks following completion of dual-targeted therapy and radiation. Median time to surgery was 62 days. There were no peri-operative adverse events. 14/19 patients underwent low anterior resection and 5 have had abdominoperineal resection. 7/19 (36.8%) showed complete pathological response (cPR), and downstaging were seen in 73.7% of the patients (14/19). The mean neoadjuvant rectal cancer score (NAR) was 10.4 and median NAR was 8.43. Conclusion: The combination of lenvatinib and capecitabine plus radiation shows encouraging safety and efficacy results. Larger randomized study is warranted to verify our findings. Citation Format: Ankita Tandon, Jessica M. Frakes, Rutika Mehta, Sarah Hoffe, Iman Imanirad, Maria E. Martinez Jimenez, Julian Sanchez, Mokenge Malafa, Seth Felder, Sophie Dessureault, Richard D. Kim. Final result of lenvatinib and capecitabine in combination with external beam radiation in treatment of locally advanced rectal cancer: Phase I clinical trial [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 4293.

1548 Background: LS is caused by a germline mutation in one of several DNA mismatch repair (MMR) genes: MLH1, MSH2, MSH6 or PMS2 (d-MMR). A minority of LS patients have MMR proficient tumors (p-MMR). ICI therapy has dramatically changed outcome of d-MMR (majority of LS patients. However, data about response to ICI in LS patients, irrespective of their tumor MMR status is scarce. The aim of this study was to evaluate outcomes of ICI therapy in all LS associated Cancer. Methods: This was a retrospective analysis of LS associated cancers treated with one of the 6 ICIs at our center. We also looked at age, sex, microsatellite status, response and survival. Results: Out of 262 LS patients analyzed, 194 had cancer and 22 received ICIs. Among the patients analyzed, the mean age at diagnosis of 1st cancer was 51 yrs. There were 10 females (47%). 10 patients had colorectal (45%), 3 urothelial (14%), 2 renal cell, 2 cholangiocarcinoma and one each of esophageal, ovarian, uterine, glioblastoma multiforme and pancreatic cancer. One patient died from progressive disease after receiving a single dose and was not included in the analysis. 17 patients (80%) received Pembrolizumab, 11 patients were microsatellite unstable (MSI), 3 were microsatellite stable (MSS) while 7 were unknown. 2 patients achieved complete response (CR) (10%), 1 patient had partial response (PR) (5%), 13 had stable disease (62%) while 5 had progressive disease (23%) leading to a disease control rate (DCR) of 76%. Of the 3 known MSS Lynch syndrome patients, 2 did not respond while the 3rd continues to respond at 9 months of therapy. Of the 5 patients who had PD, 2 were MSS, 2 unknown and 1 MSI. Among the 16 patients who responded, 15 of 16 (94%) had sustained response and have not experienced disease progression or relapse. 3 of these patients have been off therapy (1 due to immune related adverse evet) and have had no relapse. One responder progressed after 18 cycles of therapy. The DCR was 71% at 12 months as well as 48 months of follow up. Median progression survival has not been reached. Similarly, median overall survival has not been reached. Conclusions: Our study is the one of the largest reported analysis of LS associated cancer patients treated with ICIs and included LS patients with both MSI and MSS tumors. Though small, our data suggests robust DCR and prolonged responses in Lynch associated MSS tumors treated with ICI. This encouraging response in MSS tumors along with higher response rates in LS associated cancers as compared to non-LS MSI tumors, suggests that there may be additional drivers of response to ICI in LS patients leading to superior responses.

564 Background: REG is a multikinase inhibitor with immunomodulatory activity and PEMBRO is an anti-PD-1 monoclonal antibody. Both are approved as monotherapy for patients (pts) with HCC previously treated with sorafenib. Based on their potential synergistic effects, we conducted a phase 1b study of REG plus PEMBRO for first-line treatment of advanced HCC. Methods: This is an ongoing, open-label, dose-escalation study in pts with advanced HCC who had no prior systemic therapy. In the first cohort, pts received REG 120 mg/day PO for 3 weeks on/1 week off plus PEMBRO 200 mg IV q 3 weeks. In later cohorts, the REG dose could be escalated (160 mg) or reduced (80 mg) based on the modified toxicity probability interval design; the PEMBRO dose is fixed. The primary objective is safety and tolerability. Secondary objectives are to define the maximum tolerated dose (MTD) and recommended phase 2 dose, and to assess antitumor activity. Results: As of August 23, 2019, 29 pts have been treated at the REG 120 mg level. Median age is 65 years (range 32–81); 41%/55% of pts are BCLC stage B/C; 100% are Child–Pugh A; ECOG status 0/1 is 72%/28%. Dose-limiting toxicities occurred in 4/18 evaluable pts: grade (Gr) 3 increased ALT/AST with Gr 2 increased bilirubin (n = 2); Gr 3 rash (n = 2). The MTD of REG in the combination was 120 mg. Most common Gr 3 or 4 treatment-emergent adverse events (TEAEs) are shown (n = 29). There were no Gr 5 TEAEs. 59%/31% of pts had REG/PEMRO-related Gr 3 or 4 TEAEs. Dose modifications (reductions or interruptions) of REG/PEMBRO for drug-related TEAEs occurred in 59%/31% of pts. Of 23 evaluable pts, 7 (30%) had a partial response (PR) and 14 (61%) had stable disease (RECIST v1.1); 1 additional pt had PR by mRECIST. Conclusions: The combination of REG plus PEMBRO for first-line treatment of advanced HCC showed no unexpected safety signals and encouraging antitumor activity. Accrual is continuing at REG 120 mg dose and an expansion cohort evaluating REG 80 mg plus PEMBRO is planned. Clinical trial information: NCT03347292. [Table: see text]

556 Background: First line therapy for advanced cholangiocarcinoma (CCA) is currently gemcitabine and cisplatin. However, survival rarely exceeds one year with this regimen. PI3K/AKT activation has been shown to increase resistance to chemotherapy in CCA; therefore, inhibiting this pathway may improve chemotherapy’s efficacy. This phase II study evaluated the safety and efficacy of copanlisib, a potent and reversible pan-class I PI3K inhibitor, with gemcitabine and cisplatin in advanced CCA. Methods: Between July 2016 and April 2019, pts with histologically confirmed advanced/unresectable CCA received cisplatin (25 mg/m2), gemcitabine (1000mg/m2), and copanlisib 60mg on day 1 and 8, every 21 days as first line treatment. The primary endpoint was PFS at 6 months. Secondary endpoints were RR, median OS and PFS, and safety profile. A single-arm Simon’s two-stage minimax design with one-sided 10% type I error and 80% power was used. Based on ABC-01 and ABC-02 studies, PFS6 for gemcitabine and cisplatin were 57.1% and 59.3%, respectively. Therefore, PFS6 of 57% was considered not to warrant further study and ≥72% to warrant further investigation. Results: Twenty-four pts received at least one dose of the study drug (62.5% female, median age 64 years), with 70.8% intrahepatic, 16.7% extrahepatic, and 12.5% gallbladder cancer. For all pts, median OS was 13.9 months (95% CI: 6.8-17.9) and median PFS was 6.2 months (95% CI: 1.3-11.1). PFS at 6 and 12 months was 57.0% and 42.2%, and 6 and 12-month OS was 73.9% and 53.2%, respectively. Only 19 pts were considered evaluable for RR. Five pts were either lost to follow up, withdrew consent, or died before a second scan was done. Six pts achieved PR (31.5%) and 11 (57.9%) had SD. Grade 3 or higher adverse events (AE) occurred in 75% of pts. The most common grade 3/4 AEs were decreased neutrophil count (40%) and increased lipase (20%). Treated related AEs led to drug discontinuation for 3 pts (12.5%) and dose modification for 7 pts (29.2%). Conclusions: Gemcitabine, cisplatin, and copanlisib in combination did not meet the primary endpoint of 6-month PFS. However, additional correlative work is ongoing to identify a possible biomarker for copanlisib. Clinical trial information: NCT02631590.

545 Background: Hepatocellular carcinoma (HCC) is the most common primary liver malignancy, and is often advanced at the time of diagnosis. This study conducted a network meta-analysis (NMA) to assess the comparative efficacy of second-line (2L) immunotherapy and tyrosine kinase inhibitors (TKIs) without biomarker selection for advanced HCC (aHCC), including nivolumab (NIVO) + ipilimumab (IPI), cabozantinib (CABO), regorafenib (REG), and placebo (PBO). Methods: Randomized trials for CABO and REG (CELESTIAL and RESORCE) were identified through a literature review and included in the NMA. NIVO (1mg/kg) + IPI (3mg/kg) (from CHECKMATE-040) was linked into the evidence network through a matching-adjusted indirect comparison (MAIC) vs. the PBO arm of the CELESTIAL trial. The CELESTIAL trial was chosen due to the similar study design and patient population as the CHECKMATE-040 trial. Clinically relevant characteristics were matched, which included age, sex, Barcelona clinic liver cancer stage, Eastern Cooperative Oncology Group status, α-fetoprotein level, and prior treatments. The NMA included CELESTIAL, RESORCE, and the MAIC results. Investigator-assessed ORR and hazard ratio (HR) of overall survival (OS) were compared in the NMA. Results: After matching the baseline characteristics in the MAIC, the ORR of NIVO+IPI was 30.4% and the HR vs. PBO was 0.35. In the NMA, NIVO+IPI had significantly higher ORR (31.2%) compared to TKIs and PBO (REG: 4.8%; CABO: 4.2%; PBO: 1.0%, differences are presented in Table). In addition, NIVO+IPI was associated with significantly prolonged OS vs. TKIs and PBO (HR: NIVO+IPI vs. REG: 0.56; NIVO+IPI vs. CABO: 0.46; NIVO+IPI vs. PBO: 0.35). Conclusions: The NMA showed that NIVO+IPI was associated with significantly higher ORR and prolonged OS compared to TKIs as 2L treatments for aHCC. [Table: see text]

125 Background: Neoadjuvant chemo-radiation is a standard of care for locally advanced rectal cancer. Patients with pathologic complete response (pCR) have improved outcomes with less local and systemic failure. Dual targeting with platelet derived growth factor (PDGF) and vascular endothelial growth factor receptor (VEGFR) in combination with radiation can escalate tumor response with radiation. Lenvatinib is an oral multi-kinase inhibitor and had shown potent anti-tumor activity in xenograft models cultured with human colorectal cancer (CRC) lines. Methods: Patients with stage II or III rectal cancer, confirmed by endoscopic ultrasound or MRI, were recruited in 3 cohorts of 3 patients per dose level, with an expansion cohort at the MTD. Lenvatinib oral daily dose started at 14 mg (cohort 1) and was escalated to 20 mg (cohort 2) followed by 24 mg (cohort 3). In this 3+3 design, patients received dose escalation of lenvatinib with standard doses of capecitabine (850 mg/m2 PO BID) concurrent with external beam radiation on days 1-5 weekly for 28 treatments. Following completion patients underwent surgery in 6-10 weeks. Results: Twenty patients with median age of 55 were enrolled in 3 cohorts (1 patient was ineligible). There were no dose limiting toxicity at the maximum tested dose of lenvatinib (24 mg). Two patients are still awaiting surgery. 12 patients have undergone low anterior resection and 5 patients have had abdominoperineal resection. Therefore, out of 17 patients, 29.4% (5/17) showed pCR, and downstaging was observed in 71% of the patients (12/17). The mean neoadjuvant rectal cancer score (NAR) was 11.4 and median NAR was 8.43. Six patients had grade 3 adverse events (AEs) (1 rectal pain,1 transaminitis, 2 lymphopenia, 1 HTN, 1 with both leukocytosis and hyponatremia). No grade 4 AEs were noted. Most common AEs were hypertension, rectal pain, nausea, diarrhea, fatigue and dermatitis. No peri operative complications were observed. Conclusions: The study shows that the combination of lenvatinib and capecitabine with radiation is well tolerated in locally advanced rectal cancer with promising mean NAR score. The encouraging results will need to be validated in a randomized study. Clinical trial information: NCT02935309.

BACKGROUND The efficacy and safety of axitinib, a potent and selective vascular endothelial growth factor receptors 1-3 inhibitor, combined with best supportive care (BSC) was evaluated in a global, randomized, placebo-controlled phase II trial in patients with locally advanced or metastatic hepatocellular carcinoma (HCC). PATIENTS AND METHODS Patients with HCC and Child-Pugh Class A who progressed on or were intolerant to one prior antiangiogenic therapy were stratified by tumour invasion (presence/absence of extrahepatic spread and/or vascular invasion) and region (Asian/non-Asian) and randomized (2:1) to axitinib/BSC (starting dose 5 mg twice-daily) or placebo/BSC. The primary end point was overall survival (OS). RESULTS The estimated hazard ratio for OS was 0.907 [95% confidence interval (CI) 0.646-1.274; one-sided stratified P = 0.287] for axitinib/BSC (n = 134) versus placebo/BSC (n = 68), with the median (95% CI) of 12.7 (10.2-14.9) versus 9.7 (5.9-11.8) months, respectively. Results of prespecified subgroup analyses in Asian versus non-Asian patients or presence versus absence of tumour invasion were consistent with the overall population. Improvements favouring axitinib/BSC (P < 0.01) were observed in secondary efficacy end point analyses [progression-free survival (PFS), time to tumour progression (TTP), and clinical benefit rate (CBR)], and were retained among Asian patients in the prespecified subgroup analyses. Overall response rate did not differ significantly between treatments and patient-reported outcomes favoured placebo/BSC. Most common all-causality adverse events with axitinib/BSC were diarrhoea (54%), hypertension (54%), and decreased appetite (47%). Baseline serum analyses identified potential new prognostic (interleukin-6, E-selectin, interleukin-8, angiopoietin-2, migration inhibitory factor, and c-MET) or predictive (E-selectin and stromal-derived factor-1) factors for survival. CONCLUSIONS Axitinib/BSC did not improve OS over placebo/BSC in the overall population or in stratification subgroups. However, axitinib/BSC resulted in significantly longer PFS and TTP and higher CBR, with acceptable toxicity in patients with advanced HCC. TRIAL REGISTRATION ClinicalTrials.gov, NCT01210495.