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To investigate if a simplified image based scoring system assessing treatment response after neoadjuvant therapy (NAT) can predict survival in patients with pancreatic ductal adenocarcinoma (PDAC) who achieved subsequent R0 resection. Retrospective analysis of 57 PDAC patients (male = 29, 51%) with mean age of 64 at diagnosis (range 42–79) who received NAT and R0 resection. Post-NAT overall, arterial and venous imaging response was characterized as improved, similar, or worse by 2 readers independently followed by consensus review. Kaplan–Meier Analysis was performed to compare overall survival (OS) with post-NAT overall imaging response. A Multivariable Cox proportional hazards analysis was performed to evaluate the association of the following variables with OS: overall, arterial and venous radiology response, clinical staging, postoperative CA19-9, and patient age. At study conclusion, 30/57 patients were deceased (53%), 26/57 (46%) alive, and 1 patient unknown. Post-NAT, 39/57 (68.4%) had overall improved disease and 18/57 (31.6%) had similar disease. The median OS was 55.7 months (95% CI 33.4–not reached, NR) for those with improved disease vs. 53.9 months (95% CI 14.3–NR) with similar disease (p = 0.859) after NAT. Among all clinical parameters, only post-operative CA 19-9 level was associated with OS (p = 0.002) and PFS (p = 0.005), respectively. Pancreatic cancer patients who underwent R0 resection showed no difference in survival when comparing those with similar vs improved disease on post-NAT imaging.

Highlights • Complete resection is a potentially curative treatment for pancreatic cancer. • This report studies neoadjuvant chemotherapy with or without radiation. • The addition of radiation was associated with improved complete resection rates. • The addition of radiation was associated with improved pathologic down staging., Purpose Margin-negative (R0) resection is the only potentially curative treatment for patients with pancreatic ductal adenocarcinoma (PDAC). Pre-operative multi-agent chemotherapy alone (MAC) or MAC followed by pre-operative radiotherapy (MAC + RT) may be used to improve resectability and potentially survival. However, the optimal pre-operative regimen is unknown. Methods Patients with non-metastatic PDAC from 2006 to 2016 who received pre-operative MAC or MAC + RT before oncologic resection were identified in the National Cancer Database. Univariable and multivariable (MVA) associates with R0 resection were identified with logistic regression, and survival was analyzed secondarily with the Kaplan Meier method and Cox regression analysis. Results 4,599 patients were identified (MAC: 3,109, MAC + RT: 1,490). Compared to those receiving MAC, patients receiving MAC + RT were more likely to have cT3-4 disease (76% vs 64%, p

Background: This study sought to assess microsatellite and KRAS status, prevalence, and impact on outcome in stage IV colorectal cancer (CRC). Materials and Methods: The 2010 to 2016 US National Cancer Database was queried for adult patients with stage IV CRC. Prevalence of microsatellite status (microsatellite instability–high [MSI-H] or microsatellite stable [MSS]) and KRAS status (KRAS mutation or wild-type) of the primary CRC was assessed. Overall survival (OS) was evaluated using multivariable Cox proportional hazards models in patients with complete data on both microsatellite and KRAS status and information on follow-up. Results: Information on microsatellite and KRAS status was available for 10,844 and 25,712 patients, respectively, and OS data were available for 5,904 patients. The overall prevalence of MSI-H status and KRAS mutation was 3.1% and 42.4%, respectively. Prevalence of MSI-H ranged between 1.6% (rectosigmoid junction) and 5.2% (transverse colon), and between 34.7% (sigmoid colon) and 58.2% (cecum) for KRAS mutation. MSI-H rates were highest in East North Central US states (4.1%), and KRAS mutation rates were highest in West South Central US states (44.1%). Multivariable analyses revealed longer OS for patients with KRAS wild-type versus mutation status (hazard ratio [HR], 0.91; 95% CI, 0.85–0.97; P=.004), those with MSS versus MSI-H status (HR, 0.75; 95% CI, 0.62–0.9; P=.003), and those with left-sided versus right-sided CRC (multivariable HR, 0.65; 95% CI, 0.6–0.7; P<.001). The effect of KRAS mutation further varied with CRC site and microsatellite status (P=.002 for interaction). Conclusions: Depending on the primary site and US geography, stage IV CRC shows distinct mutational behavior. KRAS mutation, MSI-H, and primary CRC sidedness independently affect OS and interact with distinct prognostic profiles. Generically classifying adenocarcinomas at different sites as CRC might deprecate this diversity.

Background Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by painful and ulcerating lesions on the skin. It rarely involves the face and is often difficult to diagnose. There are few cases reported in the literature of PG involving the face. Aim To share our experience with 5 patients in whom the final diagnosis was PG involving the face, and to review the literature. Methods We report a series of 5 patients with a final diagnosis of PG involving the face and reviewed relevant literature. We searched through PubMed and EMBASE using keywords such as “face” and “pyoderma gangrenosum,” “blastomycosis-like pyoderma gangrenosum, vegetative pyoderma gangrenosum and granulomatous pyoderma gangrenosum.” Results We report 5 patients (4 females) with pyoderma gangrenosum involving the face. All 5 had a final diagnosis of superficial granulomatous PG. All cases presented with nonhealing facial ulcer most commonly on cheeks and a common histopathology of mixed inflammatory infiltrates, multinucleated giant cells, and plasma cells with some granulomatous inflammation. Conclusions PG can involve the face, and all 5 of our patients had the superficial granulomatous as the most common form.

Background TAS-102, a novel antimetabolite, is approved for treatment of refractory metastatic colorectal cancer (CRC). This study sought to determine whether the addition of TAS-102 to oxaliplatin (TAS-OX) was safe and effective in metastatic CRC previously treated with oxaliplatin. Methods This investigator-initiated, open-label, single-arm phase 1b study enrolled patients with metastatic CRC previously treated with 5-fluorouracil, irinotecan, and oxaliplatin. In dose escalation, TAS-102 was given at 3 dose levels: 25, 30, and 35 mg/m2 twice daily on day 1 to day 5 with 85 mg/m2 oxaliplatin on day 1 in 14-day cycles. The primary endpoint of dose escalation was the recommended dose for expansion, and in dose expansion, the primary endpoint was overall response rate (ORR) according to the Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1). Results Forty-one patients were treated with TAS-OX. No dose-limiting toxicities were observed in the 11 patients treated in escalation. The recommended dose for expansion was 35 mg/m2 TAS-102 twice daily on day 1 to day 5 in combination with 85 mg/m2 oxaliplatin on day 1 in 14-day cycles. In the intention-to-treat population, the ORR was 2.4% (95% CI, 0%-12.9%) with 1 of 41 patients having a partial response, although 12 (29%) had tumor shrinkage. The median progression-free survival was 2.7 months (95% CI, 2.4-4.8 months) and median overall survival was 6.8 months (95% CI, 5.7-10 months). Conclusions TAS-OX is safe with no unexpected toxicities at standard doses of each agent. The combination did not result in a clinically meaningful ORR, although progression-free survival and overall survival were encouraging in this heavily pretreated population. Lay summary For metastatic colorectal cancer, the treatment combination of TAS-102 and oxaliplatin was found to be well-tolerated and revealed no unexpected side effects. Twelve of 41 patients had reductions in the size of their tumor, and the study treatment delayed the time to tumor growth as opposed to what would be expected.

Background Randomized controlled trials (RCTs) are the gold standard for evidence-based practice, but their development and implementation is resource intensive. We aimed to describe modern RCTs in gastrointestinal (GI) cancer and identify predictors of successful accrual and publication. Materials and Methods ClinicalTrials.gov was queried for phase III GI cancer RCTs opened between 2010 and 2019 and divided into two cohorts: past and recruiting. Past trials were analyzed for predictors of successful accrual and the subset with ≥3 years follow-up were analyzed for predictors of publication. Univariate and multivariable (MVA) logistic regression were used to identify covariates associated with complete accrual and publication status. Results A total of 533 GI RCTs were opened from 2010 to 2019, 244 of which are still recruiting. In the “past” trials cohort (235/533) MVA, Asian continent of enrollment was a predictor for successful accrual, whereas trials with prolonged enrollment (duration longer than median of 960 days) trended to failed accrual. Predictors for publication on MVA included international enrollment and accrual completion. Sponsorship was not associated with accrual or publication. Notably, 33% of past trials remain unpublished, and 60% of trials that were closed early remain unpublished. Conclusion Accrual rate and the primary continent of enrollment drive both trial completion and publication in GI oncology. Accrual must be streamlined to enhance the impact of RCTs on clinical management. A large portion of trials remain unpublished, underscoring the need to encourage dissemination of all trials to, at a minimum, inform future trial design. Implications for Practice Two-thirds of gastrointestinal (GI) oncology phase III randomized controlled trials successfully accrue; however, one third of these trials are unpublished and more than half of trials that close early are unpublished. The strongest predictors for publication are successful accrual and international collaborations. Initiatives to optimize the trial enrollment process need to be explored to maximize the potential for trials to engender progress in clinical practice. Moreover, this study identified a significant publication bias in the realm of GI oncology, and the field should promote reporting of all trials in order to better inform future trial questions and design.

Despite a decreasing incidence in the USA, gastric cancer is highly prevalent worldwide. Furthermore, gastric cancer remains highly lethal with median survival of less than 1 year for metastatic disease. The backbone of therapy against metastatic gastric cancer remains cytotoxic chemotherapy, but recent advances in the molecular understanding of gastric cancer have renewed hope within that targeted agents can be leveraged to improve survival and reduce toxicity. For example, in patients with human epidermal growth factor-2 (HER2)-positive gastric cancer, the addition of trastuzumab to frontline chemotherapy improves survival. In the second line, oncologists can now administer a vascular endothelial growth factor (VEGF) receptor inhibitor, ramucirumab, as a single agent or in combination with chemotherapy, and the immune checkpoint inhibitor pembrolizumab is approved in multiple settings dependent on the Programmed Death Ligand 1 (PD-L1) status. For patients with metastatic disease, our approach to standard of care in the first-line setting is a 5FU/platinum doublet with trastuzumab for HER2-positive tumors. In the second-line setting, most patients receive ramucirumab + paclitaxel, but those that are MSI high receive pembrolizumab. For squamous cell carcinoma of the esophagus with high PD-L1 status (combined positive score (CPS) ≥ 10), we recommend pembrolizumab in the second line. While for PD-L1 ≥ 1% gastroesophageal adenocarcinoma, we do not recommend pembrolizumab before the third-line setting, although this may change in the near future for CPS ≥ 10. The future landscape for targeted therapy in gastric cancer is promising. Numerous clinical trials evaluating the combination immune therapy with molecularly targeted agents are generating much excitement. Moreover, genomic data from The Cancer Center Genome (TCGA) and Asian Cancer Research Group (ACRG) classifications is being used to identify molecular subtypes to enable future clinical trials to include biomarker-enriched patient populations.

OBJECTIVES In the 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) era, the benefit of surgery versus definitive radiation for borderline resectable (BR) and locally advanced (LA) unresectable pancreatic ductal adenocarcinoma (PDAC) is not well defined. Our primary objective was to identify the survival impact of surgery for BR and LA unresectable PDAC treated with induction FOLFIRINOX. METHODS We performed a single-center retrospective review of BR and LA PDAC treated with FOLFIRINOX from 2010 to 2018. The overall survival of surgery and consolidative radiotherapy was estimated in the Kaplan-Meier method and compared via the log-rank test. Subgroup analyses were conducted for BR and LA patients. RESULTS We identified 101 BR and LA PDAC patients treated with induction FOLFIRINOX (41 surgeries and 60 consolidative radiotherapies). Surgery patients were 68.3% (28/41) BR and 31.7% (13/41) LA, whereas consolidative radiotherapy patients were 30% (18/60) BR and 70% (42/60) LA. The R0 resection rate was 100%, and 46.3% (19/41) received preoperative radiation. Median overall survival of surgery versus consolidative radiotherapy was 42.3 versus 19.6 months, respectively (P < 0.001). On multivariate analysis, surgery associated with improved survival. CONCLUSIONS Surgery after induction FOLFIRINOX is feasible and has a clinically meaningful survival benefit in BR and LA PDAC.

Interventional oncology (IO) and oncoimmunology (OI) are fields that have significantly evolved during the last two decades and are providing new opportunities to conquer cancer with a safe and effective treatment profile. Novel IO treatments have the potential to complement OI and sensitize “cold” tumors to immunostimulatory therapies with the ultimate aim of improving patient outcomes. In this manuscript, we provide an overview of the current knowledge of the immune system in cancer, the potential for IO to modulate the immune system, and how IO and OI may synergize.

Purpose/objective(s) Following presentation of the CALGB 80803 trial, which demonstrated notably high pathologic complete response (pCR) rates with induction FOLFOX followed by chemoradiotherapy (CRT), our institution more routinely incorporated induction chemotherapy (IC) into the management of LA-EC patients. However, improvements in progression-free (PFS) or overall survival (OS) with this regimen compared to pre-operative CRT alone have not yet been shown. We hypothesized IC-CRT would lead to an improvement in OS and PFS when compared to CRT. Materials/methods Patients with operable LA-EC were eligible for analysis if they received CRT between 2013-2019. The cohort was stratified into two groups, IC-CRT vs. CRT. The Kaplan-Meier method was used to estimate OS and PFS. The cumulative incidences of local recurrence (LR), locoregional recurrence (LRR), and distant metastasis (DM) were reported. The impact of treatment group on pathologic response and surgical outcomes were assessed by Chi-square. Results 95 patients were included for analysis (IC-CRT n = 58; CRT n = 37). Baseline characteristics included median Karnofsky Performance Status 80, median weight loss 5% (IQR 0-9%), with the majority being adenocarcinoma histology (81%), T3-T4 (60%), N+ (79%), located in the distal esophagus or gastroesophageal junction (89%). Patients receiving IC-CRT were more likely to have been treated after 2016 (64% vs 38%, P = 0.021). IC was most commonly FOLFOX (74%) for a median of 3 (IQR 1-3) cycles. CRT was delivered to a median dose of 50 Gy in 25-28 fractions. Surgery was attempted in 60% and 68% of the IC-CRT and CRT cohorts, respectively. Median follow-up was 26 months. ICRT and CRT were associated with similar 2-year OS (66% [95% CI 51-78%] vs 70% [95% CI 52-83%]) and PFS (47% [95% CI 33-59%] vs 48% [95% CI 30-63%]). In the adenocarcinoma subset (n = 77), 2-year OS was 69% (95% CI 52-81%) in the IC-CRT cohort vs 61% (95% CI 40-77%) with CRT. 2-year PFS was 46% (95% CI 31-60%) and 38% (95% CI 20-56%), respectively. IC-CRT was not associated with an OS or PFS benefit among any patient subgroup. Recurrence rates were similar between the cohorts (47%) and first recurrence was most commonly DM (61% IC-CRT vs 65% CRT). Patients receiving IC-CRT compared to CRT had numeric but not statistically significant improvement in pCR (45% vs 29%, P = 0.24) and N-stage regression (72% vs 58%, P = 0.28). There was no difference in the rate of R0 resection, hospitalization, surgical complications, or treatment-related death with use of IC-CRT. Conclusion IC-CRT was not associated with improved OS or PFS in this small and perhaps underpowered cohort study. Further investigations are needed to explore the impact of IC-CRT on quality of life, symptom burden, and to see if meaningful trends develop with time.

Background: The release of ATP from dying cancer cells in response to platinum-based chemotherapy increases immunosuppressive extracellular adenosine, which can bind and activate the A2a and A2b receptors on immune cells, diminishing the effectiveness of the anti-tumor immune response. Concomitant dual adenosine receptor blockade may therefore enhance the therapeutic efficacy of some chemotherapeutic agents. Etrumadenant (etruma, AB928) is the first clinical-stage small-molecule, selective dual antagonist of A2aR and A2bR for which combination data with mFOLFOX-6 in mCRC were previously presented1,2. Here we present updated results for safety in all patients (pts) and efficacy in 3L+ pts. Methods: ARC-3 (NCT03720678) was a phase 1/1b, multicenter, open-label study to evaluate etruma + mFOLFOX-6 in pts with mCRC. Eligible pts had histologically confirmed mCRC with ≥1 measurable lesion. Pts received 75 mg (phase 1 only) or 150 mg etruma orally once daily (QD) + mFOLFOX-6. The primary objective was to assess the safety of the combination; secondary objectives included evaluation of clinical activity. Results: As of 20Nov2020, 44 pts were enrolled and received etruma (75mg: n=4; 150mg: n=40) + mFOLFOX-6. Etruma-related AEs were reported in 34 pts and were mostly Grade 1 or 2; those reported in >30% of pts were fatigue and nausea. One pt had an etruma-related Grade 3 acute kidney injury and there were no Grade 4-5 etruma-related SAEs. There were 22 efficacy-evaluable 3L+ subjects, all of which had received prior FOLFOX and/or FOLFIRI. In this subgroup, the ORR was 9.1% and the median PFS and OS were 3.9 and 15.7 mos respectively. Conclusions: Updated results confirm etruma + mFOLFOX-6 was well tolerated in pts with mCRC without significant additive toxicity and was associated with disease control in heavily pretreated pts. Based on these encouraging data, a platform study (ARC-9) has been initiated to further explore this and other combinations in mCRC pts. References 1. Cecchini M, et.al. AACR Annual Meeting 2020, Abstract# 99532. Udyavar A, et.al. SITC Annual Meeting 2020, Abstract# 338 Citation Format: Michael Cecchini, Cheng Quah, Shiyao Liu, Rachel Woloski, Akshata Udyavar, Marios Giannakis. ARC-3: Updated results of etrumadenant (AB928) + modified FOLFOX-6 (mFOLFOX-6) in metastatic colorectal cancer (mCRC) patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT129.

The prognosis of metastatic pancreatic cancer remains poor despite recent advances in treatment with multidrug chemotherapy regimens. Use of immune checkpoint inhibitors and molecular targeted therapies has so far been disappointing. This report describes a patient with chemotherapy-refractory metastatic pancreatic ductal adenocarcinoma (PDAC) whose tumor was characterized by an activating mutation in exon 19 of the epidermal growth factor receptor (EGFR). He experienced response to erlotinib for 10 months, and then developed disease progression in association with emergence of the T790M mutation. Activating EGFR mutations in cancers other than lung are uncommon, but when present may predict response to EGFR tyrosine kinase inhibitors (TKIs). Development of the T790M mutation in this case suggests that EGFR-targeted TKIs may follow similar patterns of resistance regardless of tumor type. Although actionable mutations are detected infrequently in PDAC, this case illustrates the potential benefit of offering genomic analysis to all patients with advanced disease.

Background: Induction FOLFIRINOX is increasingly used for borderline resectable (BR) and locally advanced (LA) unresectable pancreatic ductal adenocarcinoma (PDAC), but the benefit of surgery versus consolidative radiation in the FOLFIRINOX era is not well defined. Single institution experiences have included FOLFIRINOX with gemcitabine-based chemotherapy, lack a uniform comparator group to surgery, or are limited to surgical patients after FOLFIRINOX. No prospective clinical trials have assessed surgery versus radiation. Therefore, our primary objective was to identify the long-term survival impact of surgery versus radiation for BR and LA unresectable PDAC treated with induction FOLFIRINOX. Methods: We performed a single center retrospective review of BR and LA PDAC treated with FOLFIRINOX from 2010 - 2018. Patients were divided into two cohorts based on receipt of surgery versus consolidative radiotherapy. Findings: We identified 101 BR and LA PDAC patients treated with induction FOLFIRINOX; 40 underwent surgery and 61 received consolidative radiotherapy. The surgery group was 28/40 (70%) BR and 12/40 (30%) LA, while consolidative radiotherapy was 18/61 (30%) BR and 43/61 (70%) LA. The R0 resection rate was 100% for surgery and 18/40 (45%) received radiation prior to surgery. Median overall survival (OS) for surgery was 42·3 months (95% CI 24·6 - not reached) compared to a median OS of 19·6 months (95% CI 16·3 - 24·6) with consolidative radiotherapy(p = 0·0001). On multivariate analysis, surgery was associated with improved OS (HR 0·35, 95% CI 0·17 - 0·71, p=0·004). Interpretation: Surgery after induction FOLFIRINOX is feasible and has a clinically meaningful survival benefit in BR and LA PDAC compared to induction FOLFIRINOX followed by consolidative radiotherapy. Funding Statement: This research was not supported by any funding. Declaration of Interests: The authors declare no conflicts of interest relevant to this manuscript. Ethics Approval Statement: This study was approved by the Yale University institutional review board.

e18584 Background: Cancer progression rates following diagnosis are readily measured. However, the progression rate of cancer during the preclinical sojourn time is generally unobserved. Understanding the duration of preclinical stages (“dwell time”) would allow clinicians to better identify appropriate screening intervals for cancer. We therefore elicited estimates of progression rate during the preclinical sojourn time for a wide variety of malignancies from a panel of clinical experts. Methods: We used a validated consensus methodology (RAND/UCLA modified Delphi panel method) to elicit per-stage dwell time estimates for 20 solid cancers and lymphoma from experts. Eleven experienced oncologists (general and subspecialists) from community and academic centers reviewed literature on the natural history of disease and estimated in number of years (

2624 Background: KY1044, is a fully human IgG1 anti ICOS antibody designed to stimulate Teffs and to deplete ICOS high Tregs in the tumor microenvironment. Methods: Patients with advanced/metastatic malignancies received escalating doses of KY1044 as a single agent and in combination with atezolizumab 1200 mg by IV infusion every 3 weeks until disease progression or unacceptable toxicity. Dose escalation was guided by a modified toxicity probability interval design. The primary objective was to determine safety, tolerability, and maximum tolerated dose. Cohorts that were tolerated were later enriched with more subjects. AEs were classified according to CTCAE v5 and efficacy measures performed according to RECIST v1.1 every 8 weeks for the first 16 weeks and then every 12 weeks. Results: As of 16-Dec-2020, a total of 103 patients have been enrolled in the study (38 patients as monotherapy in 6 cohorts at doses ranging from 0.8 to 240 mg and 65 in combination with atezolizumab in 5 cohorts at doses 0.8 – 80 mg). 63% and 55% of patients received ≥4 prior anti-cancer therapies in the single agent and combination cohorts, respectively. All cohorts were completed without DLTs during the first 21 days of treatment. In the KY1044 single agent cohorts, 47.4% of patients experienced treatment-related AEs (TRAEs), all were grades 1 or 2. In the combination cohorts, TRAEs were observed in 58% of patients. Most of the TRAEs were grade 1 or 2 apart from 8 TRAEs that were ≥grade 3 occurring in 43 weeks (range 45 to 66 weeks). Conclusions: KY1044 is well tolerated as single agent and in combination with atezolizumab. Objective responses have been observed in this phase 1 part of the study. The phase 1 expansion and phase 2 part of the study is ongoing. Clinical trial information: NCT03829501.

TPS150 Background: ATP release from dying cancer cells in response to platinum-based chemotherapy increases extracellular immunosuppressive adenosine, which binds and activates the A2a and A2b receptors on immune cells. Adenosine-mediated signaling impairs activation, proliferation, and cytotoxic activity of effector T cells, resulting in inhibition of antitumor activity. Concomitant adenosine receptor blockade may therefore enhance the therapeutic efficacy of chemo/immunotherapy regimens. Etrumadenant (AB928), the first clinical-stage, small-molecule, dual adenosine receptor antagonist, is highly potent, pharmacodynamically active, and has been well tolerated in dose escalation studies as monotherapy or combined with chemo/immunotherapy. Recently, results were reported for the ARC-3 phase 1/1b study of etrumadenant + modified 5-fluorouracil + oxaliplatin (mFOLFOX-6) in patients (pts) with mCRC. In this study, etrumadenant + mFOLFOX-6 was well tolerated without significant additive toxicity. Disease control was observed in patients with RAS/BRAF mutated mCRC, as well as 3L+ disease previously treated with FOLFOX and/or FOLFIRI (PR and/or SD >4 mo). Due to deep responses in 1L-3L+ pts, 6 pts had the opportunity to pursue surgery and radiotherapy with curative intent. The encouraging results from ARC-3 warrant further evaluation of etrumadenant-based combination therapy for mCRC. Methods: ARC-9 is a phase 1b/2, multicohort, open-label, randomized platform study designed to evaluate safety and clinical activity of etrumadenant (150 mg orally once daily [QD]) in combination with standard-of-care (SOC) regimens or novel therapeutics in pts with mCRC (Table). Cohort eligibility is based on prior anticancer treatment history. Pts enrolled in Cohorts A and B will be randomized (2:1) into the experimental vs SOC arms. Cohort C consists of a single arm to allow inclusion of novel agents as they become available with built in early stopping rules for futility. Pts who progress on the SOC arm of Cohort A can enroll in Cohort B; pts who progress on the SOC arm of Cohort B can crossover to the experimental arm. Primary endpoints across cohorts are shown in Table. Safety monitoring will occur throughout the trial, disease assessments will occur every 8 weeks, and correlative study pre- and on-treatment biopsies will be performed. [Table: see text]

82 Background: The MORPHEUS platform consists of multiple, global, open-label, randomized Phase Ib/II trials designed to identify early efficacy signals and safety of treatment (tx) combinations across tumor types. Isatuximab (isa; anti-CD38) targets CD38 receptors expressed on immunosuppressive cells in the tumor microenvironment. We hypothesized atezolizumab (atezo; anti–PD-L1) + isa would induce an anti-tumor response beyond that of regorafenib (rego), a multi-kinase inhibitor, in patients (pts) with tx-refractory metastatic colorectal cancer (mCRC). Methods: This randomized Phase Ib/II trial (NCT03555149) enrolled pts with microsatellite stable/mismatched repair proficient mCRC who had received ≤ 2 prior tx lines (fluoropyrimidine-, oxaliplatin- or irinotecan-containing chemotherapy plus a biologic agent). Pts received atezo (1200 mg intravenously [IV] every 3 weeks [q3w]) + isa (10 mg/kg IV q3w) or control tx with rego (160 mg orally days 1–21; dose escalation to 160 mg during Cycle 1 allowed per institutional guidelines). The primary endpoint was objective response rate (ORR; investigator-assessed RECIST 1.1); secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate (DCR) and safety. Results: Data cutoff date was March 3, 2020. Fifteen pts received atezo + isa and 13 pts received rego. Fourteen atezo + isa pts (93.3%) and 11 control arm pts (84.6%) had received 2 prior lines of tx; 9 atezo + isa pts (60.0%) and 9 control pts (69.2%) had liver metastases at enrollment. No responses were seen in either arm; 3 pts receiving atezo + isa (20.0%) and 8 control pts (61.5%) had stable disease as their best response. DCR (response and/or stable disease ≥ 12 weeks) was 6.7% with atezo + isa and 15.4% with control. One pt treated with atezo + isa beyond progression had prolonged disease stabilization. Median PFS was 1.4 mo (95% CI: 1.4, 1.8) with atezo + isa and 2.8 mo (95% CI: 1.6, 3.1) in the control arm; median OS was 5.1 mo (95% CI: 3.1, 7.8) with atezo + isa and 10.2 mo (95% CI: 4.8, not reached) with control. Tx-related adverse events (AEs, Grade 1-4) occurred in 13 atezo + isa pts (86.7%), and 12 control pts (92.3%). The most common tx-related AEs with atezo + isa were infusion-related reaction (73.3%), nausea (26.7%) and fatigue (20.0%). No Grade 5 AEs occurred in the atezo + isa arm, 1 (7.7%) was reported in the control arm (sepsis, considered unrelated to study tx). No atezo + isa pts and 1 control-arm pt (7.7%) withdrew from treatment due to a tx-related AE. Biomarker analyses did not identify any significant trends related to efficacy. Conclusions: In this trial, superior efficacy of atezo + isa vs rego was not shown. However, the atezo + isa combination was well tolerated, with a manageable safety profile. Clinical trial information: NCT03555149.

462 Background: To evaluate epidemiology, treatment and outcomes of stage 4 gastrointestinal stromal tumors (GIST). Methods: The 2010-2016 United States National Cancer Database was queried for adult patients diagnosed with invasive GIST (ICD code 8936) at AJCC stage 4, without prior malignant disease. Overall survival (OS) was evaluated using Cox proportional hazards regression, accounting for potential confounders in multivariable models. Results: A total of 1,578 stage 4 GIST were included (13.3% of all GIST) with a male:female ratio of 1.38:1. The most common cancer site was the stomach (55.4%) and small intestine (40% of stage 4 GIST). At diagnosis, median age was 62 years and median tumor diameter 10 cm. Distant organ metastases were reported in 58.7%, the most frequent being hepatic (n = 801, 50.8% of stage 4 GIST). The majority of stage 4 GIST patients received systemic therapy (78.6%), either alone (35.4%) or combined surgery+systemic therapy (43.3%). Systemic therapy was administered neoadjuvant in 6.9%, adjuvant in 32%, and neoadjuvant+adjuvant in 5.1% of surgically resected patients. Another n = 204 patients (12.9% of all stage 4 GIST) were treated with surgical resection alone. GIST overall survival rates were 88%, 77%, 67% and 51% at 1, 2, 3, and 5 years, respectively. On multivariable Cox proportional hazard models, primary GIST treatment independently affected OS: compared to combined surgery+systemic therapy, OS was shorter for patients receiving systemic therapy alone (HR = 2.77 (95% CI: 2.12-3.61, p < 0.001)) and no treatment (HR = 4.2 (95% CI: 2.75-6.43, p < 0.001)). No significant OS difference was evident comparing surgery+systemic therapy and surgery alone (HR = 1.23 (95% CI: 0.88-1.72, p = 0.227)). In subgroup analyses of patients undergoing surgical resection, no statistically significant OS difference was evident comparing neoadjuvant, adjuvant and combined neoadjuvant+adjuvant systemic therapy on multivariable analyses. Treatment at non-academic vs. academic centers was associated with shorter OS (multivariable HR = 1.36 (95% CI: 1.1-1.69, p = 0.005)). Further independent OS predictors were male sex (vs. female HR = 1.28 (95% CI: 1.03-1.59, p = 0.023)), older age, higher comorbidities, higher cancer grade, and larger cancer diameter. Conclusions: Stage 4 GIST is a rare gastrointestinal malignancy that most commonly manifests in the stomach and small intestine in male patients, with frequent hepatic metastases and excellent 5-year OS rates of up to 51%. Combined surgery+systemic therapy demonstrates best outcomes, although surgical resection alone might yield comparable results in selected patients.

Purpose: Cancer staging is critical for prognostication, treatment planning, and determining clinical trial eligibility. Electronic health records (EHRs) have structured staging modules, but physician use is inconsistent. Typically, stage is entered as unstructured free text in clinical notes and cannot easily be used for reporting. Methods: We created an Epic Best Practice Advisory (BPA) decision support tool that requires physicians to enter cancer stage in a structured module. If certain conditions are met, the BPA is triggered as a hard stop, and the physician cannot chart until staging is complete or a reason for not staging is selected. We used Plan, Do, Study, Act methodology to inform the intervention and compared preexisting staging rates to rates at 4, 8, and 12 months postintervention. Results: For 12 months before BPA implementation, 1,480 of 5,222 (28%) patients had cancer stage structured within the Epic problem list. From 1 to 4 months after the BPA 2,057 of 1,788 (115%) cases were staged in Epic. In the 5- to 8-month period after the BPA, 1,057 of 1,893 (56%) cases were staged, and 9 to 12 months after the BPA 1,082 of 1,817 (60%) were staged. Conclusion: Electronic decision support improves the rate of structured cancer staging at our institution. The staging rates between 56% and 60% for the 5- to 8-month and 9- to 12-month periods likely reflect accurate postintervention staging rates, whereas the initial 115% rate for 1 to 4 months is inflated by providers staging cancers diagnosed before the BPA.

Background: The release of ATP from dying cancer cells in response to platinum-based chemotherapy increases extracellular immunosuppressive adenosine (A), which binds to and activates the A2a and A2b receptors on immune cells resulting in an ineffective anti-tumor immune response. Concomitant adenosine receptor blockade may therefore enhance the therapeutic efficacy of some chemotherapeutic agents. AB928, the first clinical-stage small molecule dual adenosine receptor antagonist, is highly potent, pharmacodynamically active, and has been well tolerated in dose escalation studies as a single agent or in combination with chemo/immunotherapy. Methods: ARC-3 (NCT03720678) is a Phase 1/1b, open-label study in participants (pts) with advanced CRC. Phase 1 escalation identified AB928 150 mg orally once daily as the recommended dose in combination with standard mFOLFOX-6. Phase 1b expansion is ongoing and includes at least 15 and up to 40 pts. Eligible pts must have unresectable or mCRC, ECOG performance status 0-1, and at least one RECIST measurable lesion. Phase 1 eligibility included up to 5 lines of prior therapy; Phase 1b is similarly scoped. Exploratory biomarker analyses include immunohistochemistry of the adenosine axis, tumoral next gene sequencing, and tumor/blood immune correlates. Results: As of 27Dec19, 21 pts received AB928 150 mg + mFOLFOX-6: 7 in Phase 1 and 14 in Phase 1b. All previously treated pts (n=12) were FOLFOX- and/or FOLFIRI-experienced. Prior metastatic therapies range from 3 to 5 in Phase 1 escalation and 0 to 3 in Phase 1b expansion. Adverse events (AEs) reported in >30% of pts included fatigue, diarrhea, and thrombocytopenia. AEs related to AB928 occurred in 13 pts and were mostly mild to moderate. AB928-related Grade 3 AEs reported by 3 pts were diarrhea, AST increase, and neutropenia; there were no Grade 4-5 AB928-related AEs. Out of 15 evaluable pts, by investigator assessment, the disease control rate was 100% with 2 partial responses (13%; 1 confirmed, 1 pending confirmation) and 13 stable disease (87%). Of pts with stable disease, 6/13 (46%) had tumor shrinkage >15%. Median time on treatment was 15.4 (range: 1.7 - 40.6+) and 11.9 (range: 2.7 - 15.7+) weeks for Phase 1 and Phase 1b, respectively, with initiation of Phase 1b dosing on 09Sep19. Enrollment up to 40 pts is proceeding based on early efficacy gates; 15 pts are currently receiving study treatment. Conclusions: AB928 with mFOLFOX-6 has been well tolerated without significant evidence of additive toxicity in pts with mCRC. Combination treatment was associated with disease control in all evaluable pts, including those with microsatellite stable and RAS/BRAF mutated mCRC. Additional updates on the safety, clinical activity, and correlative biomarker results for all escalation/expansion pts will be presented. Citation Format: Michael Cecchini, Manuel Modiano, Fadi Braiteh, Olivia S. Gardner, Houston N. Gilbert, Daniel DiRenzo, Lisa Seitz, Matt J. Walters, Fangfang Yin, Rachel Woloski, Melissa C. Paoloni, Ki Y. Chung. Efficacy and safety of AB928 plus modified FOLFOX-6 (mFOLFOX-6) in participants with metastatic colorectal cancer (mCRC): Initial results at the recommended dose for expansion (ARC-3) [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 LB-387.

Background: Gut microbiome composition affects response to PD-1 blockade; and recent proof of concept studies suggest that gut microbiome manipulation is effective in reversing resistance to PD-1 blockade. VE800 is an oral live biotherapeutic consisting of 11 distinct non-pathogenic, non-toxigenic, commensal bacterial strains manufactured in lyophilized form. VE800 induces CD8+ T cell infiltrate into tumors; and significantly enhances anti-tumor activity of PD-1 blockade preclinically in multiple tumor models in a CD103+ dendritic cell and major histocompatibility (MHC) class I dependent fashion (Tanoue et al., 2019). Retrospective analysis of cancer patient's (pt) samples also suggests that greater VE800 strain abundance is associated with improved response to PD-1 blockade. The objective of this phase I study is to evaluate the safety, tolerability, and clinical activity of VE800 administered orally in combination with nivolumab in pts with select cancers. Methods: CONSORTIUM-IO (NCT04208958) is an open-label, first-in-human study evaluating VE800 and nivolumab combination in pts with anti-PD-1/PD-L1 relapsed/refractory melanoma, anti-PD-1/PD-L1 naïve gastric/gastroesophageal junction (GEJ) adenocarcinoma and anti-PD-1/PD-L1 naïve microsatellite-stable (MSS) colorectal cancer. Following a 5-day course of oral vancomycin 125mg QID, VE800 will be administered daily along with nivolumab (480mg Q4W). A single dose level of VE800 will be evaluated. In the interests of maximizing safety, a Simon 2-stage design will be used for each disease cohort. Although no dose-limiting toxicities (DLT) are expected, the first 3 pts will be enrolled serially 1 week apart; and safety data of the first 6 pts will be reviewed prior to further accrual. Pts will continue to receive VE800/nivolumab combination until disease progression or unacceptable toxicity. Primary endpoints include safety, tolerability; and clinical activity by objective response rate (ORR) per RECIST v1.1. Secondary endpoints include duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS); and metagenomic strain-level analysis of degree/duration of VE800 strain colonization. Exploratory endpoints include tumor and blood immunophenotyping, serum/stool metabolomics and global changes in fecal microbiome composition. CONSORTIUM-IO is currently actively enrolling pts. Citation Format: Diwakar Davar, Judy S. Wang, Michael Cecchini, Zev Wainberg, Martin Gutierrez, Anita Turk, Rose Szabady, Jason Norman, Bernat Olle, Bruce Roberts, Dmitri Bobilev. Consortium-IO: A safety and efficacy study of VE800 in combination with nivolumab in previously treated patients with select advanced metastatic cancers [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 CT246.

e16052 Background: To assess microsatellite instability (MSI) and KRAS mutation prevalence, discrepancies and their impact on outcome in AJCC stage IV colorectal adenocarcinoma (colorectal cancer; CRC). Methods: The 2010-2016 United States National Cancer Database was queried for stage IV CRC patients > 18yo and information on MSI and KRAS mutation. Microsatellite status was stratified as stable microsatellites (MSS, including low instability) and microsatellite instability high (MSI-H). KRAS status was stratified as mutation and wildtype. Prevalence and discrepancies were evaluated according to patient demographics, US geography and CRC factors. Overall survival (OS) was assessed using Cox proportional hazards models adjusting for age, gender, race, comorbidities, metastatic burden, CRC treatment, treatment center type, and year of CRC diagnosis. A priori, a statistical interaction test between microsatellite status, KRAS status and primary CRC site was planned. Results: Microsatellite/KRAS status was available for n = 10,844/n = 25,712 patients, respectively. OS was assessed in n = 5,904 patients with data on both microsatellite and KRAS status, and follow-up. Overall prevalence of MSI-H was 3.1% and KRAS mutation 42.4%. Microsatellite and KRAS status varied according to primary CR site, as presented in Table. Further variation was evident according to US-geography, with MSI-H rates ranging from 1.6% to 4.1%, and KRAS mutation rates ranging from 41.1% to 44%. On multivariable analyses, longer OS was observed in patients with KRAS wildtype versus mutation (HR = 0.91, 95% CI: 0.85-0.97 p = 0.004), MSS versus MSI-H (HR = 0.75, 95% CI: 0.62-0.9, p = 0.003), and left-sided versus right-sided CRC (HR = 0.65, 95% CI: 0.6-0.7, p < 0.001). The effect of KRAS mutation further varied with CRC site and microsatellite status (interaction p = 0.002). Conclusions: Depending on its primary site and US geography, stage IV CRC shows distinct mutational behavior. KRAS mutation, MSI-H, MSI-H and primary CRC sidedness independently affect overall survival and interact with distinct prognostic profiles. Generically classifying adenocarcinomas of different site as “CRC” might deprecate this diversity. [Table: see text]

770 Background: Patients (pts) receiving treatment for metastatic pancreatic cancer (MPC) experience significant symptoms, treatment related side effects and psychosocial burdens. The ASCO guidelines recommend early palliative care consultation (PCC) to improve quality of life and survival. However, limited real-world data is available regarding the timing of PCC, hospice enrollment and location of death (LOD) in pts with MPC. Methods: We conducted a retrospective observational analysis of pts treated with chemotherapy for MPC at the Yale Smilow Cancer Hospital and affiliated community care centers (CCC) from January 2011 to April 2019. Patient demographics, treatment dates, initial PCC, enrollment of hospice at the time of death and LOD were manually abstracted from the electronic medical record. Univariate and multivariable logistic regression analyses were conducted to predict for PCC and death outside the hospital. Results: Of 363 pts identified with MPC who received chemotherapy, 38% (138) had a PCC. 67% (93) of patients’ initial PCC was in the hospital versus 33% (45) in the outpatient setting. The median time from the start of first-line chemotherapy to the first PCC was 5.2 months (interquartile range [IQR] 1.2 – 12.9). The median time from the first PCC to death was 1.5 months (IQR 0.5 – 4.42). At the time of our analysis, 300 pts had died and of those 76% (229) were enrolled on hospice at the time of death while 24% (71) were not. With respect to LOD, 47% (139) of pts died at home with hospice, 31% (94) at an inpatient hospice facility and 22% (67) died in the hospital. Female gender was associated with an increased likelihood of a PCC (HR 1.78, 95% CI 1.07-2.94, P = 0.026). Pts treated at a CCC were less likely to have a PCC (HR 0.21, 95% CI 0.12-0.36, P < 0.001). A PCC was not associated with a higher likelihood of death outside the hospital (HR 1.31, 95% CI 0.75-2.29, P = 0.346). Conclusions: Although most pts with MPC enroll in hospice, PCC is generally underutilized. In fact, many pts receive PCC near the end of life and in the hospital. Further studies are warranted to determine how best to incorporate early PCC to maximize supportive care for pts with MPC.

609 Background: While carcinoid and neuroendocrine tumors (NET) can manifest throughout the human body, approximately 2/3 of these tumors arise in the gastrointestinal (GI) tract. Methods: The 2019 version of the National Cancer Database was searched for adult patients with carcinoid or neuroendocrine tumors of the GI tract. Tumor incidence, patient demographics, treatment and cancer variables of GI carcinoid/NETs were compared to other GI cancers. Cox proportional hazards models were used to evaluate overall survival (OS). Results: A total of 101,744 patients were included. Carcinoid/NET incidence varied with primary location, with highest proportion in the small intestine (55.7% of all small intestinal cancers). Compared to other histologies, carcinoid/NETs were more common in younger patients (median age 60 vs. 68years, p < 0.001) and African Americans (18 vs 12%, p < 0.001). Median carcinoid/NET diameter 15mm vs. 40mm for other cancers (p < 0.001). Carcinoid/NETs were diagnosed at lower stages than other histologies (AJCC stage 3/4, 30% vs. 47%, p < 0.001), with most metastases in the liver (8.9%). Stage 1/2 carcinoid/NETs were most often treated by surgical resection with or without concurrent chemotherapy (65%; 22%), whereas stage 3/4 patients received chemotherapy alone or in combination with surgical resection more commonly (39%; 25%). After multivariable adjustment, primary cancer site emerged as an independent prognosticator: longest OS was observed in patients with carcinoid/NET of the small intestines (vs. colonic frame HR = 0.40, 95% CI: 0.37-0.44, p < 0.001). Comparable results were evident in patients with hepatic metastases (small intestines vs. colonic frame carcinoid/NETs; HR = 0.20, 95% CI: 0.17-0.24, p < 0.001). Other independent OS prognosticators were patient age, gender, race and comorbidities, as well as tumor size, stage and treatment. Conclusions: Compared to other GI-associated tumors, carcinoid/NETs are more common in younger patients, African Americans, diagnosed with smaller diameter at low stage. Carcinoid/NETs of the small intestines are associated with improved overall survival compared to other primary disease sites.

769 Background: FOLFIRINOX (FFX) and Gemcitabine plus nab-paclitaxel (GN) are established first line (1L) therapies for metastatic pancreatic cancer (MPC) but real-world data on their comparative effectiveness is limited. Methods: All cases of MPC treated with 1L FFX or GN at Yale Smilow Cancer Hospital and the affiliated community care centers (CCC) from January 2011 – April 2019 were reviewed. Patient (pt) demographics, prior therapy, initial and subsequent dose reductions (DR), time to treatment discontinuation (TTD), overall survival (OS), and second line (2L) treatment data were manually abstracted from the electronic medical record. Categorical and continuous variables were compared between 1L FFX and GN cohorts via the Chi-squared and Wilcoxon rank-sum tests. Median OS was calculated by the Kaplan-Meier method. Results: We identified 363 MPC pts treated with 1L FFX or GN; 269 (74%) pts were treated with FFX and 94 (26%) with GN as 1L therapy. 204 (56%) pts were treated at the main campus and 159 (44%) at a CCC. Demographics and baseline characteristics (FFX/GN) were as follows: gender (male) 55% / 41%; race (white) 82% / 77%; age < 76 90% / 71% ( P < 0.001). 332 (91%) of pts received no prior therapy; 21 (6%) had prior surgery plus adjuvant gemcitabine and 10 (3%) had surgery alone. 98% of FFX-treated pts were treated with upfront DR, compared to 78% of GN-treated pts ( P= 0.003). 78% and 53% of FFX-treated and GN-treated pts, respectively, had subsequent DR ( P< 0.001). Median TTD was 4.8 months with FFX and 3.4 months with GN ( P= 0.0029) and the median OS was 11.3 months with FFX versus 7.2 months with GN ( P < 0.0001). After 1L, 33% and 61% of FFX- and GN-treated pts, respectively, received no further chemotherapy ( P< 0.001). Conclusions: In the largest manually abstracted retrospective analysis to date, MPC pts treated with 1L FFX were younger, more likely to receive 2L therapy, and had increased survival compared to pts treated with GN. The OS of pts treated with FFX was similar to the OS reported by Conroy et al despite upfront dose attenuations in 98% of pts. A randomized trial is needed to confirm optimal sequencing of chemotherapy in MPC.

Background: Hyperclustering of death receptor 5 (DR5) and subsequent induction of apoptosis, which normally occurs upon binding of its ligand TRAIL, can be mimicked by agonistic antibodies (Abs). However, clinical efficacy of conventional DR5 Abs has been disappointing. To improve antibody-mediated DR5 clustering on cancer cells, we utilized the HexaBody® antibody technology. This antibody platform is based on the discovery that IgG molecules can organize into hexamers through intermolecular Fc-Fc interactions upon binding to membrane-bound targets. HexaBody molecules are IgG1 Abs with a single point mutation in the Fc domain that enhances hexamerization. HexaBody-DR5/DR5 is a 1:1 mixture of two non-competing anti-DR5 HexaBody molecules that induces potent caspase-dependent apoptosis through hexamer-dependent hyperclustering of DR5 on the cell surface. We previously showed that HexaBody-DR5/DR5 induced superior potency compared to conventional DR5 antibodies in vitro and in vivo. Methods: To obtain preclinical proof-of-concept for targeting specific solid tumors using HexaBody-DR5/DR5, we performed a patient-derived xenograft (PDX) mouse clinical trial (1 mouse per group design) using a large number of colorectal (CRC) (100), gastric (19), urothelial (13), non-small cell lung cancer (NSCLC) (90), and triple-negative breast cancer (TNBC) (20) PDX models. Results: HexaBody-DR5/DR5 showed potent anti-tumor activity (tumor stasis or tumor regression) in a substantial proportion of the CRC (36%), gastric (42%) and urothelial (54%) models. Additional in vivo studies comparing single vs multiple dosing demonstrated that maximal anti-tumor activity was already achieved after a single dose of HexaBody-DR5/DR5. A Phase 1/2 clinical trial to determine the RP2D and assess clinical safety of HexaBody-DR5/DR5 in cancer patients is currently ongoing (NCT03576131), from which a case study will be presented. Conclusions: Potent anti-tumor activity of HexaBody-DR5/DR5 was observed in large and diverse panels of CRC, gastric and urothelial PDX models, providing preclinical rationale for the clinical evaluation of HexaBody-DR5/DR5 in these indications. Citation Format: Marije B Overdijk, Michael Cecchini, Kristin Strumane, Marcel Brandhorst, Andreas Lingnau, Paul W.H.I. Parren, Merete Ellekilde-Pedersen, Ulf Forssmann, Tahamtan Ahmadi, A. Kate Sasser, Janine Schuurman, Esther C.W. Breij, Patricia LoRusso. HexaBody-DR5/DR5 (GEN1029) shows potent preclinical antitumor activity in a variety of patient-derived xenograft (PDX) tumor models [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C025. doi:10.1158/1535-7163.TARG-19-C025

272 Background: Expert knowledge is often shared among academic oncologists at tumor boards (TBs) at National Cancer Institute Designated Cancer Centers (NCI-CCs), but not documented or made accessible to community oncologists. Using an oncologist-only question and answer (Q&A) website, we sought to disseminate expert insights from TBs at NCI-CCs to provide educational benefit to the oncology community. Methods: A process was designed with faculty at 11 NCI-CCs to document and share discussions from TBs focused on areas of clinical complexity and practice variation on theMednet.org, an interactive Q&A website of over 8,700 US oncologists. One faculty member from each TB was selected as a site leader. She or he distilled discussions about patient management from the TB into a question that addressed the clinical situation being discussed. After the question was posted, faculty at the participating NCI-CCs were asked to answer the question on theMednet. Answers were peer reviewed, indexed, stored and disseminated via email newsletters to registered oncologists. Community engagement was measured by Q&A page views, upvotes of Q&A, and poll participation. Results: A total of 15 Breast, Thoracic, and Gastrointestinal programs from 11 NCI-CCs participated. Between 12/2016 and 5/2019, faculty highlighted 146 questions from their TBs. Q&A were viewed 43,291 times by 3,585 oncologists including 2,264 community oncologists. One hundred and eighty-four answers are posted by 56 academic physicians and peer reviewed by 76 academic physicians. One hundred and eighty-five publications were cited. Community oncologists upvoted Q&A 808 times and voted in 45 polls related to the questions 1,667 times. Viewership of NCI-CC Q&A increased by 419% over time. Q&A were repeatedly searched and viewed, with 90% of all TB Q&A viewed every month. Conclusions: Via the online Q&A theMednet platform, NCI-CC providers effectively made expert knowledge easily accessible to community oncologists across the US. Timely access to evidence based recommendations from expert faculty can inform future practice choices in the community. [Table: see text]

437 Background: Induction FFX for PC deemed either BR or LA at diagnosis provides an opportunity to downstage pts with the aim of an R0 surgery. The addition of RT after induction FFX may further downstage. However, there is a paucity of data regarding long-term survival for BR and LA patients successfully downstaged and resected. We performed a retrospective review of BR and LA PC treated with induction FFX +/- RT followed by surgery or consolidative RT at the Yale Cancer Center (YCC) to assess survival in these two cohorts. Methods: Clinical data was abstracted for pts with BR or LA PC who had surgery or received consolidative RT without surgery after induction FFX +/- RT at the YCC from 2010-2018. Surgical pts were re-reviewed by a radiologist to assess vascular involvement (BR vs. LA) using NCCN criteria. PFS and OS for surgery and consolidative RT were analyzed by the Kaplan-Meier method. Survival was compared via the log rank test. Results: 102 pts met inclusion criteria (BR=47, LA=55), 41 pts had surgery [BR=29/47 (62%) LA=12/55 (22%)] and 61 pts had consolidative RT [(BR= 18/47 (38%), LA= 43/55 (78%)] after induction FFX. 18 surgery pts received RT prior to resection and all surgery pts had R0 resection. Median follow up was 25 mo (range 5 – 97). Median PFS with surgery was 22 mo (95% CI 15 – 59) vs 14 mo (95% CI 10.9 – 20.1) with consolidative RT (p

630 Background: TAS-102 is an oral combination of the anti-metabolite 5-trifluorothymidine (FTD) and a thymidine phosphorylase inhibitor (TPI), preventing the degradation of FTD. It is approved as mCRC monotherapy with improved survival. Oxaliplatin is often reintroduced in mCRC after progressive disease (PD) on maintenance 5-FU although response is poor. The decreased efficacy may be related to acquired 5-FU resistance. We therefore explored the safety and efficacy of oxaliplatin in combination with an alternative and non cross-resistant anti-metabolite, TAS-102. Methods: Phase 1 of TAS-OX is a 3+3 dose-escalating study at a starting dose of TAS-102 25 mg/m2 and oxaliplatin 85 mg/m2 with three dose levels (table). TAS-102 is administered days 1-5 and oxaliplatin day 1, every 2 weeks. Eligible patients previously received 5FU, oxaliplatin, irinotecan, appropriate biologics, had measurable disease, usual laboratory parameters, and ECOG PS 0-1. The primary objective was to determine the recommended phase II dose (RP2D). Results: Twelve patients were evaluable for dose limiting toxicity (DLT). No DLTs were observed. Treatment related grade ≥ 3 AEs were neutropenia (n = 4) and thrombocytopenia (n = 1). No AEs resulted in treatment discontinuation. Two patients (dose levels 2 and 3) required dose reductions for prolonged neutropenia. Median number of cycles for all treated patients was 6 ± 4. The disease control rate (DCR) at 8 weeks was 67%. Best response in all evaluable patients was 1 PR (8%) 7 (59%) SD and 4 (33%) PD. Conclusions: The RP2D of TAS-102 is 35 mg/m2 in combination with oxaliplatin 85 mg/m2. No DLTs were observed and no unexpected AEs were seen. The DCR in this heavily pretreated patient population is encouraging. Phase II is now enrolling at this dose (NCT 02848079). Clinical trial information: NCT02848079. [Table: see text]

Background TAS-102 (trifluridine and tipiracil hydrochloride; a novel combination oral nucleoside anti-tumor agent) has recently received regulatory approval for patients with refractory metastatic colorectal cancer (mCRC). Internal review of data at a single-institution showed a trend towards better overall survival (OS) for patients who experienced chemotherapy-induced neutropenia at 1-month (CIN-1-month). To explore this finding further, a cohort study was designed based on outcome data from three centers in United States and one from Japan. Methods CIN-1-month after starting TAS-102 was defined by the Common Terminology Criteria for Adverse Events (CTCAE), version 4.03 as a neutrophil count decrease of ≥ grade 2 (absolute neutrophil count

To the editor: The widespread implementation of electronic medical records (EMR) allow providers ready access to large amounts of patient information, and for some specialties much of the data needed to provide recommendations can be gathered electronically.[1][1] Electronic consultation (e-consult

TPS4137Background: Gastric cancer remains a significant health problem in the US and globally with more than 951,600 annual cases worldwide. Moreover, the incidence of GEJ-centered adenocarcinoma i...

61 Background: Early results from recent studies using immune checkpoint blockade targeting programmed death 1 (PD-1) have suggested that pleomorphic undifferentiated sarcomas may have response rates of over 40%. As of now predictive biomarkers for response and resistance have been incompletely characterized. Methods: A 58-year-old man who received radiation for a head and neck squamous cell cancer, developed a radiation-induced undifferentiated pleomorphic sarcoma (UPS) in his neck in 2014. His sarcoma was resected but recurred in 2015. He received adjuvant radiation after surgical debulking in September 2015 and was found on radiation simulation scan to have new widespread metastatic disease involving liver, lung, and bone. He started treatment on nivolumab in November 2015 and has had a sustained near complete response in all lesions. Results: All sites had a near complete response to nivolumab treatment. Pre treatment tissue analysis revealed no mutations or amplifications in 134 cancer-related genes, on the Oncomine Assay (Life Technologies, Inc.). Normal tissue was noted to be heterozygous for BRCA2 N372H, while the allelic fraction of the 372H variant in the tumor was found to be 85%. Programmed death ligand-1 (PDL-1) immunohistochemistry staining of the tumor tissue was negative. Tumor infiltrating lymphocytes were not noted in the tumor tissue specimen. Conclusions: This patient exhibited a near complete response to all sites of disease, with remaining PET avidity in a single hilar node. The role of the BRCA2 variant and radiation just prior to starting nivolumab is unknown. BRCA2 N372H is a common single nucleotide polymorphism (SNP) in the population with a minor allele frequency of 0.25. Although the effect of the 372H variant on BRCA2 protein structure is predicted to be minimal, population studies have suggested a slightly increased risk of breast and ovarian cancer in homozygotes. It is possible that the radiation treatment to the site of recurrence in the head and neck, resulted in an abscopal effect enhancing the therapeutic effect of nivolumab therapy. Additional testing on his tissue is being done to further investigate the response.

Background: Yellow nail syndrome (YNS) is a rare clinical entity of unknown etiology that is characterized by a triad of yellow nails, respiratory manifestations, and lymphedema. The condition appears in the mid- to later years of life and only rarely in childhood. We describe a rare case of YNS with an atypical clinical presentation consisting of only yellow and dystrophic nails in a 2- year-old female since birth. Objective: A case of congenital YNS with only dystrophic and yellow nails is reported. Methods and Results: A 2-year-old female presented with yellow nails since birth. There was no positive family history. Physical examination revealed 20 thickened, dystrophic, yellow nails with onycholysis. There was no evidence of respiratory manifestations or lymphedema. Conclusion: Although rare, YNS can present as a congenital clinical entity and persist after birth. Pediatric patients with YNS show different clinical manifestations than the classic adult patient. The presence of yellow and dystrophic nails in the absence of respiratory and lymphatic manifestations may be the only sign of pathology and warrants close monitoring as progression to more serious complications can occur.

e15124Background: TAS-102 (tri-fluoro-thymidine and tipiracil hydrochloride; a novel combination oral nucleoside anti-tumour agent) was recently approved for patients with refractory metastatic col...

e18188Background: Multidisciplinary tumor board (MTB) meetings have become a standard for evidence based decision making at medical centers worldwide. We believe that the expertise at subspecialty ...

Introduction: Electronic consultation (e-consult) is a healthcare delivery method in which a consultant provides input on the management of a patient by reviewing the medical chart without a face to face visit. This method is especially suited to systems that use a comprehensive electronic medical record (EMR). E-consults have the potential to improve efficiency and timeliness of care, save costs, prevent unnecessary patient visits, and address shortage of specialists. They may be especially valuable in rural areas, and for patients who have difficulty traveling. Published data regarding the utility and efficacy of remote hematology consultations are limited. At the VA Connecticut Healthcare System (VACT) electronic hematology consultations were initiated in July of 2011 as part of a national program. Providers are allowed to choose between referring their patient to a face to face visit or an e-consult, based on their clinical judgment and their patients’ preferences. The purpose of this study is to evaluate the impact of electronic hematology consultation on patient care, to measure its effect on the face-to-face encounters at the VACT hematology clinics, and to assess provider and patient satisfaction. Methods: We conducted a retrospective review of 300 patients who had a hematology e-consult between the years 2011 to 2013 at VACT. Data abstracted included demographics, diagnoses, timeliness of care, and need for face to face visits. In addition patient and provider satisfaction were evaluated by anonymous surveys. Hematology e-consults were performed by board eligible/certified hematologists based on review of the EMR and peripheral blood smears as appropriate. When necessary, recommendations were made to refer a patient for a face to face evaluation in the hematology clinic. Our study was approved by our local IRB. Results: The most common reason for a hematology e-consult was anemia (25%), followed by anticoagulation in patients with venous thromboembolism (14%), thrombocytopenia (8%), erythrocytosis (7%), leukocytosis (6%), paraproteinemia (6%), neutropenia (6%), pancytopenia (2%), abnormal iron indices (2.5%) and abnormal coagulation profiles (2%). Additional reasons included thrombocytosis, macrocytosis, lymphocytosis, eosinophilia, thalassemia, splenomegaly, lymphadenopathy, and hemoglobinopathies. The vast majority of patients were male (95%) with an average age of 63 +16 years. Average distance between the patients’ homes to our medical center was 36.6+22 miles. Electronic hematology consultations were completed on average within 16 days. We observed that implementation of hematology e-consults was accompanied by a 15% decrease in the annual number of face to face hematology visits (from 377 in 2011 to 319 in 2013), while the number of Veterans enrolled at VACT during that period did not change significantly. Only in 42 patients (14%) a face to face hematology consultation was recommended after completion of the e-consult. Of the 50 patients that were sent satisfaction surveys, completion rate was 34% and 65% replied that they preferred an e-consult over a face to face visit. Among 61 providers that received surveys, 15 (25%) responded and 100% indicated that they were “satisfied” or “very satisfied” with the process. Conclusions: Our study suggests that electronic hematology consultation can address many common hematology diagnoses and can prevent the need for a face to face visit in the majority of patients selected for an e-consult by their referring providers. These consultations can be provided without compromising patient and provider satisfaction and may decrease the need for face to face visits. This could have important implications for the delivery of hematology care, especially in healthcare systems that utilize an EMR. Disclosures No relevant conflicts of interest to declare.

Metastatic melanoma is frequently treated with immune activating therapy, which poses a theoretical risk of inducing graft versus host disease (GVHD) in those who have received allogeneic stem cell transplantation. The literature reporting the safety of immunotherapy in post transplant patients is limited. We report two patients with metastatic melanoma who received treatment with immunotherapy after allogeneic stem cell transplantation that did not result in GVHD.