Citations

TPS489 Background: Tucatinib (TUC), a highly selective HER2-directed TKI approved in multiple regions for HER2+ metastatic breast cancer, is being investigated as a novel therapy for patients (pts) with metastatic colorectal cancer, gastric cancer, and other GI tumors. Preclinical and clinical data have shown HER2-targeted agents may improve clinical outcomes. In xenograft models of HER2+ and HER2-mutated tumors, dual targeting of HER2 with TUC + trastuzumab (Tras) showed superior activity to either agent alone (Kulukian 2020). Interim results from the MOUNTAINEER study have shown promising activity for TUC + Tras in HER2+ colorectal cancer. In 23 response-evaluable pts, an objective response rate (ORR) of 52% was observed with a median progression-free survival (PFS) of 8.1 months (mo) (Strickler 2019). The prognosis for pts with biliary tract cancers (BTCs) remain poor, and treatment options are limited. Given that approximately 12%-15% of BTC pts are HER2+, and 1%-8% have HER2 mutations, TUC + Tras warrants further evaluation in this patient population. The SGNTUC-019 basket study (NCT04579380) is evaluating TUC + Tras in pts with previously treated, locally advanced, unresectable or metastatic solid tumors including BTC that display HER2 overexpression/amplification or activating mutations. We describe the design of the BTC cohort. Methods: SGNTUC-019 is a multi-cohort, open-label, international Phase 2 study. Pts must be ≥18 years old; have an ECOG PS of ≤1; have adequate hepatic, hematological, renal, and cardiac functions; and have no previous exposure to HER2-directed therapy. BTC pts must have progressed on or after ≥1 previous line of treatment. The HER2+ BTC cohort will enroll 12 response-evaluable pts. If >2 responses are observed, the cohort will be expanded to 30 pts. HER2-mutated BTC patients may also be enrolled in a 30 pts cohort for other HER2-mutated solid tumors. The primary objective is antitumor activity with confirmed ORR as the primary endpoint. Secondary efficacy endpoints include disease control rate, duration of response, PFS, and OS. For eligibility, HER2 alterations can be demonstrated by HER2 overexpression/amplification in tumor tissue by prior IHC/ISH, or by HER2 amplification/mutation in a prior or on-study NGS assay of ctDNA or prior tissue NGS assay. Pts will receive TUC 300 mg orally twice a day and Tras 8 mg/kg intravenously on Cycle 1 Day 1 then 6 mg/kg every 21 days from Cycle 2 Day 1. Disease assessments per RECIST 1.1 are every 6 weeks for the first 24 weeks, then every 12 weeks. Quality of life will be evaluated every 2 cycles using EQ-5D-5L. Sites are currently enrolling within the US, EU and Asia-Pacific. Clinical trial information: NCT04579380.

TPS376 Background: Human epidermal growth factor receptor 2 ( HER2) gene amplification or protein overexpression (HER2+) occurs in many gastrointestinal (GI) cancers; thus, there is interest in evaluating HER2-targeted therapies in these tumor types. Tucatinib (TUC) is a highly selective HER2-directed tyrosine kinase inhibitor with minimal EGFR inhibition, approved in multiple regions for HER2+ metastatic breast cancer. In patient-derived xenograft models of HER2+ tumors (including esophageal, gastric, and colorectal cancers), TUC + trastuzumab showed superior anti-tumor activity compared with either agent alone (Kulukian 2020). In the MOUNTAINEER study, TUC + trastuzumab in HER2+ metastatic colorectal cancer (CRC) resulted in an objective response rate of 52% and a median duration of response of 10.4 months (interim results, Strickler 2019). The SGNTUC-024 study (NCT04430738) will evaluate TUC + trastuzumab with and without oxaliplatin-based chemotherapy or pembrolizumab in patients with unresectable or metastatic GI cancers. Methods: SGNTUC-024 is an open-label, dose escalation and expansion phase 1b/2 trial. Phase 1b assesses the safety and tolerability of TUC + trastuzumab + either FOLFOX (fluorouracil, leucovorin, and oxaliplatin) or CAPOX (capecitabine and oxaliplatin) with or without pembrolizumab. One chemotherapy-free cohort is planned (TUC + trastuzumab + pembrolizumab). The initial phase 1b cohort enrolled patients with gastric, esophageal, and gastroesophageal junction (GEJ) adenocarcinomas; cholangiocarcinoma; gallbladder carcinoma; and CRC to receive TUC (150 mg oral [PO] twice daily [BID]) + trastuzumab + FOLFOX. Subsequent phase 1b cohorts will receive TUC (300 mg PO BID) + trastuzumab + either FOLFOX or CAPOX. Once the recommended dose for use with oxaliplatin is identified, cohorts enrolling patients with gastric, esophageal, and GEJ adenocarcinomas will open with patients receiving TUC (300 mg PO BID) + trastuzumab + pembrolizumab with or without either FOLFOX or CAPOX. Phase 2 will expand the assessment of safety and efficacy and enroll 2 cohorts: patients with gastric, esophageal, and GEJ adenocarcinomas (to receive TUC + trastuzumab + pembrolizumab + either FOLFOX or CAPOX, Cohort A) and patients with CRC (to receive TUC + trastuzumab + FOLFOX, Cohort B). Safety and efficacy will be summarized with descriptive statistics. Patients that receive chemotherapy must be eligible for an oxaliplatin-based regimen as standard of care. Patients with irradiated or resected central nervous system (CNS) lesions may enroll, and patients with known active CNS lesions may be eligible for phase 2. The phase 1b portion of the trial is currently enrolling. Clinical trial information: NCT04430738.

663 Background: GI malignancies continue to be a major cause of cancer related deaths, despite advances in therapy options. In pancreatic cancer, the presence of homologous recombination mutations (HRM) has been shown to confer increased sensitivity to platinum chemotherapy. However, the role of HRM mutations in other GI cancers remains to be determined. The focus of this study is to evaluate the prognostic nature of core and noncore HRM in nonpancreatic GI cancers. Additionally, we aim to understand the predictive nature of these mutations related to platinum exposure. Methods: This was a retrospective review of patients at Moffitt Cancer Center with a primary stage IV nonpancreatic GI cancer treated with platinum therapy. All patients had next generation sequencing and were in the Clinical Genomics Action Committee database between 1/1/2013 and 11/1/2020. All patients had either a core HRM (BRCA1, BRCA2, PALB2) or noncore HRM (such as ATM, ATR, BARD1, BRIP1, FANCA, NBN, and RAD51). Patients were grouped into core HRM vs. noncore HRM. Response was stratified between responders (complete response and partial response) vs. non responders (stable disease and progressive disease), based on RECIST criteria. Progression free survival and overall survival were estimated using Kaplan-Meier method, and the log-rank test was used to assess the difference in progression free survival (PFS) and overall survival (OS) by HRM status and type of platinum therapy used. Results: There were 72 patients included in the study: the majority of patients were male (65.3%) and Caucasian (87.5%). Twenty-one (29.2%) patients had a core HRM and 51 (70.8%) had a noncore HRM. There was no significant difference in response rate between patients with core HRM and patients with noncore HRM for evaluable patients (n = 66): 20.0% of patients with core HRM vs. 21.7% of patients with noncore HRM demonstrated a response to platinum therapy (p = 0.41). An improved OS was noted for patients with core HRM vs. those with noncore HRM at 68.9 vs. 24.3 months (p = 0.019). An improved PFS was also seen in patients with core HRM at 10.4 months vs. 6.3 months with noncore HRM (p = 0.027). There was no difference in PFS based on type of platinum therapy used (oxaliplatin vs. carboplatin vs. cisplatin), while an improved OS was noted for patients treated with oxaliplatin vs. carboplatin vs. cisplatin at 43.1 vs. 28.2 vs. 16.0 months (p = 0.011). Conclusions: Our study demonstrated that in stage IV nonpancreatic GI malignancies treated with platinum therapy, patients with core HRM had a greater OS and PFS compared to those with noncore HRM, suggesting a potential prognostic and predictive role of these mutations. Further studies are needed to confirm our findings.

174 Background: Colorectal cancer (CRC), while one of the most common cancer diagnoses, can behave heterogeneously based on molecular characteristics. A subset of patients (pts) with CRC are characterized with mismatch repair deficiency (MMR-d), these pts exhibit encouraging responses to immunotherapy. The predictive nature of various factors, such as BRAF status, age, and MMR-D protein loss type, have been investigated in pts with MMR-d CRC. However, the prognostic role of these factors has not been well established. The purpose of this study was to identify characteristics that influence survival in MMR-d mCRC. Methods: This study evaluated pts with MMR-d mCRC in the Flatiron database. Overall survival (OS) was determined from date of diagnosis of stage IV disease to date of death and stratified based on age greater than or less than 50 years, BRAF mutation status, RAS mutation status, and type of MMR gene loss. For statistical analysis, the Chi-Square test was implemented to determine the prognostic significance of clinical and molecular features. Univariate and multivariate analyses were determined through the Cox regression model. Results: There were 1,101 pts in the study. The majority of pts were older than 50 (79.7%), Caucasian (75%), and had ECOG 0-1 (83.4%). Among the 803 pts with known BRAF status, 44.3% (n=356) had BRAF V600E mutation and 55.7% (n=447) were BRAF wildtype. Pts with BRAF V600E mutation had OS of 18.9 months vs. 33.2 months for pts with wild type BRAF (HR 1.52, 95% CI: 1.25-1.86, p<0.001). Pts older than 50 had a lower median OS vs. those who were ≤50 at 21.4 months vs. 38.7 months (HR 1.66, 95% CI: 1.33-2.07, p<0.001). When comparing MSH2/MSH6 mutations to MLH1/PMS2, a trend towards improved OS was seen with median survival of 35.2 months vs. 22.7 months, respectively (HR 0.79, 95% CI: 0.61-1.02, p=0.067). On multivariate analysis, BRAF mutation and older age continued to be associated with differences in survival, while KRAS mutation and specific MMR gene loss did not. Conclusions: BRAF V600E mutation and age greater than 50 are associated with decreased survival for pts with MMR-D mCRC. KRAS mutations and specific MMR alterations are not associated with differences in survival.

Abstract Background Anthracycline use in metastatic breast cancer (MBC) is hindered by cumulative exposure limits and risk of cardiotoxicity. Pixantrone, a novel aza-anthracenedione with structural similarities to mitoxantrone and anthracyclines, is theorized to exhibit less cardiotoxicity, mainly due to lack of iron binding. We conducted a randomized phase II study to evaluate the efficacy and safety of 2 dosing schedules of pixantrone in patients with refractory HER2-negative MBC. Methods Intravenous pixantrone was administered at 180 mg/m2 every 3 weeks (group A) versus 85 mg/m2 on days 1, 8, and 15 of a 28-day cycle (group B). Primary endpoint was objective response rate (ORR) and secondary endpoints included progression-free survival (PFS), median 6-month PFS, overall survival (OS), safety, quality of life, and serial assessment of circulating tumor cells. A 20% ORR was targeted as sufficient for further testing of pixantrone in this patient population. Results Forty-five patients were evaluable, with 2 confirmed partial responses in group A and 1 in group B. The trial was terminated due to insufficient activity. Overall median PFS and OS were 2.8 (95% confidence interval [CI]: 2.0-4.1) and 16.8 (95% CI: 8.9-21.6) months, respectively. Notable overall grade 3-4 adverse events were the following: neutrophil count decrease (62%), fatigue (16%), and decrease in ejection fraction (EF) (4%). Conclusion Pixantrone has insufficient activity in the second- and third-line MBC setting. It appears, however, to have limited cardiotoxicity. (ClinicalTrials.gov ID: NCT01086605).

Abstract Background Previous prospective studies highlighted dairy intake as a risk factor for Parkinson's disease (PD), particularly in men. It is unclear whether this association is causal or explained by reverse causation or confounding. Objective The aim is to examine the association between genetically predicted dairy intake and PD using two‐sample Mendelian randomization (MR). Methods We genotyped a well‐established instrumental variable for dairy intake located in the lactase gene (rs4988235) within the Courage‐PD consortium (23 studies; 9823 patients and 8376 controls of European ancestry). Results Based on a dominant model, there was an association between genetic predisposition toward higher dairy intake and PD (odds ratio [OR] per one serving per day = 1.70, 95% confidence interval = 1.12–2.60, P = 0.013) that was restricted to men (OR = 2.50 [1.37–4.56], P = 0.003; P ‐difference with women = 0.029). Conclusions Using MR, our findings provide further support for a causal relationship between dairy intake and higher PD risk, not biased by confounding or reverse causation. Further studies are needed to elucidate the underlying mechanisms. © 2022 International Parkinson and Movement Disorder Society

Background The epidemiology of ventricular arrhythmias (VAs) in patients with advanced heart failure (HF) is not well defined. Methods and Results Residents of Olmsted County, Minnesota, with advanced HF from 2007 to 2017 were identified using the 2018 European Society of Cardiology criteria. Billing codes were used to capture VAs; severe VAs requiring emergency care were defined as events associated with emergency department visits or hospitalizations. The cumulative incidence of VAs postadvanced HF was estimated with the Kaplan–Meier method. Multivariable Cox analyses were used to determine the following: (1) Predictors of severe VAs postadvanced HF; and (2) Impact of severe VAs on mortality. Of 936 patients with advanced HF, 261 (27.9%) had a history of VA. The 1‐year cumulative incidence of severe VAs postadvanced HF was 5.4%. Prior VAs (hazard ratio [HR] 2.22 [95% CI, 1.26–3.89], P =0.006) and left ventricular ejection fraction <40% (HR, 3.79 [95% CI, 1.72–8.39], P <0.001) were independently associated with increased severe VA risk postadvanced HF. New‐onset severe VAs were associated with increased mortality (HR, 4.41 [95% CI, 2.80–6.94]; P <0.001), whereas severe VAs in patients with prior VAs had no significant association with mortality risk (HR, 1.08 [95% CI, 0.65–1.78]; P =0.77). Severe VAs were associated with increased mortality in patients without implantable cardioverter defibrillators (HR, 4.89 [95% CI, 2.89–8.26]; P <0.001), but not in patients with implantable cardioverter defibrillators (HR, 1.42 [95% CI, 0.92–2.19]; P =0.11). Conclusions Patients with left ventricular ejection fraction <40% and prior VAs have increased risk of severe VA postadvanced HF. New‐onset severe VAs or severe VAs without implantable cardioverter defibrillators postadvanced HF are associated with increased mortality.

Abstract Introduction: Allogeneic stem cell transplantation (allo-SCT) can be curative for patients with hematologic malignancies. Despite optimization of supportive measures, the risk of non-relapse mortality is a particularly important consideration in older individuals. Sarcopenia, defined as low skeletal muscle mass, has been shown to be associated with decreased overall survival in cancer patients and may identify individuals at higher risk of treatment-related complications. Methods: Using Mayo Clinic Arizona's hematopoietic stem cell transplantation database, patients aged 60 years or older who underwent allo-SCT between 2008 and 2018 were identified. Patients who underwent abdominal computed tomography (CT) at our institution within 90 days prior to their transplant date were included in the study. The skeletal muscle area (SMA) was obtained using a fully automated algorithm for segmenting abdominal CT images to quantify body composition based on a deep learning approach (Weston et al., Radiology, 2019). The skeletal muscle index (SMI) was then calculated using the SMA and the subject's height at the time the CT was obtained. Sarcopenia was defined based on previously described consensus (Cruz-Jentoft et al., Age Ageing, 2010; Magudia et al., Radiology, 2021). T-tests and Fisher's exact tests compared patient characteristics between groups, where appropriate. Kaplan-Meier methods were used to construct survival times. Log-rank tests compared survival distributions and Cox proportional hazards models estimated hazard ratios. Results: A total of 79 patients met inclusion criteria (Table 1). Of these, 50 (63%, n=50/79) had sarcopenia, and 29 (37%, n=29/79) had normal skeletal muscle mass. Among the sarcopenia group, 43 (86%, n=43/50) had SMI measurements. No differences were seen between groups in age at transplant, sex, Karnofsky performance scale, disease risk index, or conditioning regimen intent. There was no statistically significant difference in overall survival between those with sarcopenia and those with normal skeletal muscle mass (log-rank p=0.18). Median survival was 3.3 years (95% CI: 0.8, not estimable (NE)) for those with sarcopenia and 3.6 years (95% CI: 1.3, NE) for those with normal skeletal muscle mass. Given the infrequency of events, the upper bounds of the median survival confidence intervals were not estimable. The unadjusted hazard ratio (HR) for sarcopenia versus normal skeletal muscle mass was 1.65 (95% CI: 0.79, 3.47; p=0.18). Males had a higher mean SMI than females, as expected (50.4 versus 37.5, p&lt;0.001; mean difference 13.0, 95% CI: 8.9, 17.1). Without considering sex, higher or lower SMI was not associated with survival time in a Cox model in those with sarcopenia (HR: 0.97, 95% CI: 0.92, 1.03; p=0.32). Sex alone was also not associated with any survival benefit among these 43 patients. After adjusting for the difference seen in SMI between sexes, on average, those with higher SMI were associated with a survival benefit (HR: 0.92, 95% CI: 0.84, 0.99; p=0.039). This amounts to roughly an 8% reduction in hazard rate as SMI increased. Conclusions: The presence of sarcopenia alone was not associated with overall survival in patients 60 years and older undergoing allo-SCT for hematologic malignancy. Rating sarcopenia severity using SMI may assist in identifying high risk individuals with sarcopenia as lower sarcopenia severity was associated with improved overall survival. Further studies are warranted to explore the possible impacts of interventions directed at improving skeletal muscle mass on transplant-related outcomes. Figure 1 Figure 1. Disclosures Gaulin: DeciBio: Honoraria; Olson Research Group: Honoraria. Jain: CareDx: Other: for advisory board participation; CTI Biopharma: Research Funding; Syneos Health: Research Funding; Bristol Myers Squibb: Other: for advisory board participation; Targeted Healthcare Communications: Consultancy. Palmer: PharmaEssentia: Research Funding; Incyte: Research Funding; Sierra Oncology: Consultancy, Research Funding; CTI BioPharma: Consultancy, Research Funding; Protagonist: Consultancy, Research Funding.

Abstract Venomous snakebite is an important cause of preventable death. The World Health Organization (WHO) set a goal to halve snakebite mortality by 2030. We used verbal autopsy and vital registration data to model the proportion of venomous animal deaths due to snakes by location, age, year, and sex, and applied these proportions to venomous animal contact mortality estimates from the Global Burden of Disease 2019 study. In 2019, 63,400 people (95% uncertainty interval 38,900–78,600) died globally from snakebites, which was equal to an age-standardized mortality rate (ASMR) of 0.8 deaths (0.5–1.0) per 100,000 and represents a 36% (2–49) decrease in ASMR since 1990. India had the greatest number of deaths in 2019, equal to an ASMR of 4.0 per 100,000 (2.3-5.0). We forecast mortality will continue to decline, but not sufficiently to meet the WHO’s goals. Improved data collection should be prioritized to help target interventions, improve burden estimation, and monitor progress.