Mahipal, Amit

e16259 Background: Patients with KRAS mutant (mt) pancreatic ductal adenocarcinoma (PADC) have worse survival outcomes compared to KRAS wild-type (wt) PDAC patients. However, the prognostic implication of the KRAS mutation subtype (e.g. G12D, G12R, G12V and Q61) remains unclear. Furthermore, the clinical and molecular characteristics associated with these mutation subtypes remain not well defined. Methods: A retrospective review was conducted on patients with KRAS PDAC who underwent Next Generation Sequencing at Mayo Clinic between December 1, 2018 and December 1, 2021. Their somatic mutations, RNA expression, demographics, disease characteristics, therapies offered, and clinical outcomes were collected via chart review. Results on KRAS wt were reported previously; KRAS mt are reported here. Results: A total of 158 KRAS mt patients (at diagnosis: average age 63.8 years, 57% male, 88 (56%) Stage IV) were included. 10% of patients had KRAS Q61 mutation, 14% G12R, 30% G12V and 46% G12D. G12R had a longer overall survival (OS) compared to the others (median 24.8 vs 17.5 months, unadjusted hazard ratio (HR) 0.68, p=0.05), particularly in patients with localized disease at diagnosis (median 35.4 vs 28.3 months, p=0.08). Among patients with metastatic disease at diagnosis, G12V had the lowest OS (median 9.8 vs 12.4 months, unadjusted HR 1.8, p=0.02). 137 (87%) patients had at least one pathogenic somatic variant, with statistically significant differences in SMAD4, TP53, MYC, RB1, KMT2D, RBM10, RNF43, KDM6A, KMT2C, RBM10, LRP1B, PIK3CA, and SMARC among the KRAS mt subtypes. 82 (52%) patients had at least one RNA expression variant, with statistically significant differences in CCND1, CCNE1, HRAS, MET, EGFR, and ERB3 among KRAS mt subtypes. Between these subtypes, there were no statistically significant differences in TMB value, location of PDAC or subsequent metastasis, lines of treatment (average 2.3), age at diagnosis, or gender. Conclusions: KRAS mt subtypes may confer different PDAC phenotypes. In our cohort, G12R is associated with improved OS while G12V correlates with worse prognosis in de novo metastatic disease. Additionally, there are differences in genomic variations and RNA expression between the KRAS mt subtypes. To further examine this, transcriptomic analysis is underway. [Table: see text]

Abstract Background Female underrepresentation in oncology clinical trials can result in outcome disparities. We evaluated female participant representation in US oncology trials by intervention type, cancer site, and funding. Materials and Methods Data were extracted from the publicly available Aggregate Analysis of ClinicalTrials.gov database. Initially, 270,172 studies were identified. Following the exclusion of trials using Medical Subject Heading terms, manual review, those with incomplete status, non-US location, sex-specific organ cancers, or lacking participant sex data, 1650 trials consisting of 240,776 participants remained. The primary outcome was participation to prevalence ratio (PPR): percent females among trial participants divided by percent females in the disease population per US Surveillance, Epidemiology, and End Results Program data. PPRs of 0.8-1.2 reflect proportional female representation. Results Females represented 46.9% of participants (95% CI, 45.4-48.4); mean PPR for all trials was 0.912. Females were underrepresented in surgical (PPR 0.74) and other invasive (PPR 0.69) oncology trials. Among cancer sites, females were underrepresented in bladder (odds ratio [OR] 0.48, 95% CI 0.26-0.91, P = .02), head/neck (OR 0.44, 95% CI 0.29-0.68, P < .01), stomach (OR 0.40, 95% CI 0.23-0.70, P < .01), and esophageal (OR 0.40 95% CI 0.22-0.74, P < .01) trials. Hematologic (OR 1.78, 95% CI 1.09-1.82, P < .01) and pancreatic (OR 2.18, 95% CI 1.46-3.26, P < .01) trials had higher odds of proportional female representation. Industry-funded trials had greater odds of proportional female representation (OR 1.41, 95% CI 1.09-1.82, P = .01) than US government and academic-funded trials. Conclusions Stakeholders should look to hematologic, pancreatic, and industry-funded cancer trials as exemplars of female participant representation and consider female representation when interpreting trial results.

89 Background: Enterocolitis is a potentially fatal toxicity of CAPE. The safety of infusional 5-FU-based regimens in patients developing severe enterocolitis with CAPE is not well established in the literature. Methods: After institutional review board approval, a database search identified patients who received infusional 5-FU-based regimens between January 2015 and July 2022 in a tertiary care cancer center after experiencing severe CAPE-induced enterocolitis, defined as the presence of grade 3 or higher diarrhea and features of enterocolitis on computed tomography (CT) scan. Data on patient characteristics, grade of CAPE-induced diarrhea, clinical course, details of 5-FU-based regimens administered after recovery, and outcomes were collected by retrospective electronic chart review. Results: Among the 791 patients treated with CAPE during the study period, 27 (3.4%) developed grade 3 or higher diarrhea, and 15 of these 27 patients (1.9%) had evidence of enterocolitis on CT scan. All patients were treated with supportive measures. All but 1 patient recovered fully; 1 patient died due to a condition unrelated to CAPE toxicity. After complete recovery, 7 patients aged 46 to 69 years (median, 68 years) received FOLFOX (oxaliplatin and infusional 5-FU). The time interval between recovery from CAPE-induced enterocolitis and the start of infusional 5-FU ranged from 4 to 20 weeks (median, 12 weeks), with 3 patients starting 5-FU within 4-5 weeks of recovery. Standard dose 5-FU (2400 mg/m2 over 46 hours) was given to 2 of the 7 patients; the remaining 5 patients received 50% to 80% of the standard dose at the beginning of treatment, but eventually tolerated the standard dose. All patients tolerated 5-FU infusion without experiencing any grade 2 or higher 5-FU induced GI toxicity. Conclusions: Most patients developing severe enterocolitis with CAPE recover fully with appropriate supportive measures. Infusional 5-FU-based regimens appear to be safe in this patient group. Severe CAPE-induced enterocolitis should not preclude the use of infusional 5-FU-based regimens, especially in curative-intent settings such as adjuvant therapy.

616 Background: Cholangiocarcinoma (CCA) is an aggressive, heterogenous group of neoplasms that arise from the epithelial lining of bile ducts that have dismal poor prognosis. A recent epidemiological study in the United States demonstrated a steady increase in the incidence of cholangiocarcinoma from 2001 to 2017 with a predominant increase in the intrahepatic sub-type (iCCA). We sought to evaluate the future incidence of cholangiocarcinoma stratified based on the subtype, age, sex, and race, that could possibly help plan prevention, control, and treatment strategies for this cancer. Methods: We obtained histologically confirmed cases of cholangiocarcinoma (ICD-0-3 Site: C220, C21, and C240) from National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) 18 registries between 2000 to 2017 and predicted the incidence between the years 2018-2029. We applied age-period-cohort models to estimate future cholangiocarcinoma incidence rates (per 100, 000) and the estimated disease burden by multiplying incidence forecasts by corresponding US Census population projections. Results: A total of 12,737 and 8,395 patients with iCCA and extra-hepatic cholangiocarcinoma (eCCA) were included in the final analysis. The median age of iCCA cohort was 64 (range: 20-79) years and 46.4% were females whereas in eCCA the median age was 66 (range: 20-79) years and 43.8% were females. The overall observed age-adjusted incidence of iCCA between 2000-2017 was 1.07, which is predicted to increase to 2.13 by 2029 (99% increase) with a predominant increase in incidence rate observed in the age groups 70-79 and White males and females. Interestingly, incidence rate remained stable in Black and Asian males and in Asian females. Similarly, as compared to 2001-2017, the incidence of eCCA is projected to increase from 0.74 to 1.01 by 2029 (36.5% increase) with predominant increase noted in Black and Hispanic cohorts. In contrast, we noticed a relatively stable and decreasing incidence rate in White and Asian females, respectively. Conclusions: We predict an overall increased incidence of both iCCA and eCCA over the next decade especially in certain subgroups warranting the urgent need for preventive strategies. Further epidemiological studies are needed to determine the etiological factors contributing to predicted increase in incidence rate.

615 Background: Accounting for 90% of primary liver cancers, HCC is the fourth-most common cause of cancer-related deaths in the United States. While the vaccination against hepatitis B and awareness on hepatitis C transmission possibly decreased the incidence of HCC in Eastern World, there was an uptrend in the HCC incidence the Western World over the past few years possibly related to metabolic causes. With this changing paradigm of hepatocellular carcinoma, it is important to estimate its future burden stratified based on the age, sex, and race, that could possibly help plan prevention, control, and treatment strategies for this cancer. Methods: We obtained histologically confirmed cases of HCC (ICD-0-3 Site: C220 and 228; codes: 8170-8175) from National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) 18 registries between 2000 to 2017 and predicted the incidence between the years 2018-2029. We applied age-period-cohort models to estimate future HCC incidence rates (per 100, 000) and the estimated disease burden by multiplying incidence forecasts by corresponding US Census population projections. Results: A total of 76029 patients with HCC were included in the final analysis. The median age was 62 (range: 20-79) years with male predominance (70%). The overall observed age-adjusted incidence of HCC between 2000-2017 was 6.22, which is predicted to increase to 9.03 by 2029 with a predominant increase in incidence rate observed in the age groups 70-79 and White males. Interestingly, we noticed a progressive decrease in incidence rate in Asian cohort (both males and females) and Black males. Incidence rates by sub-groups based on the age, sex, and race are summarized in the Table. Conclusions: We predict an overall increased incidence of hepatocellular carcinoma over the next decade in the United States, predominantly in 70-79 years age group irrespective sex and race, with an exception to Asian cohort probably representing differential risk factors. Further epidemiological studies are needed to determine the etiological factors contributing to predicted increase in incidence rate.[Table: see text]

559 Background: Cabozantinib, a multikanase inhibitor, is approved by the Food and Drug Administration (FDA) for treatment of advanced stage hepatocellular carcinoma (HCC) following progression on sorafenib. The CELESTIAL study which demonstrated benefit from cabozantinib following sorafenib included only patients with Child Pugh class A liver function. Recently, bevacizumab plus atezolizumab has replaced sorafenib as the first line treatment for HCC. It is unclear whether there is benefit from using Cabozantinib following progression on immunotherapy as CELESTIAL trial included very few patients who received prior immunotherapy. We describe the outcomes of individuals with advanced stage HCC treated with Cabozantinib following progression on immunotherapy. Methods: This was a multicenter, retrospective analysis of patients with advanced HCC diagnosed between 2010-2021 at Mayo Clinic Arizona, Florida, and Minnesota. Progression free survival (PFS) and median overall survival analysis were performed using Kaplan-Meier method. Results: We identified a total of 26 patients with advanced stage HCC who received cabozantinib following progression on immunotherapy. The median age of patients was 61 years (range, 39 – 81) and the majority were male (85%). Eighteen (72%) patients had Child Pugh A at initiation of cabozantinib therapy. Four (15%) patients received cabozantinib as second line therapy, the rest received it as third line or later. PFS on cabozantinib was 2.1 months (95% CI: 1.3 – 3.9) and median overall survival from time of cabozantinib initiation was 7.7 months (95% CI: 5.3 – 14.9). PFS was shorter with Child Pugh Class B, 1.3 months (95% CI: 0.9 – NE) compared to those with Child Pugh Class A, 2.1 months (95% CI: 1.5 – 4); although this difference was not significant (p=0.55). Common adverse events included fatigue (50%), anorexia (35%), aspartate aminotransferase (AST) elevation (35%), and diarrhea (31%); 7 (26%) patients experienced Grade 3 or greater adverse events including hypertension, diarrhea, anorexia, and bowel obstruction. Two patients discontinued cabozantinib due to side effects including one for uncontrolled blood pressure elevations and the other due to fatigue. Conclusions: The optimal sequencing of therapy for patients with advanced HCC following progression on immunotherapy is unknown. Treatment with cabozantinib may improve clinical outcomes following progression on immunotherapy with similar adverse event profile. This study included patients with Child Pugh class B liver disease (28%) and heavily pretreated population and demonstrated mPFS and mOS similar to other work examining outcomes of cabozantinib in real world setting after progression on sorafenib. Further studies to determine optimal treatment sequencing for this patient population are needed.

539 Background: Tinengotinib is a spectrum-selective multi-kinase inhibitor with a unique FGFR-binding mechanism. It potently inhibits FGFR2 fusion/rearrangement and acquired resistant mutations in pre-clinical models and early clinical studies in cholangiocarcinoma (CCA). Here we present the preliminary efficacy and safety of tinengotinib (TT-00420) in a phase II trial TT420C1206 (NCT04919642). Methods: Eligible patients (pts) with advanced/metastatic CCA exhausting standard treatment options received tinengotinib 10 mg QD. Pts were enrolled into four cohorts using historical FGFR alteration status: FGFR2 fusion(s) with primary progression on previous FGFR inhibitor (FGFRi) (A1) or progression after prior response to FGFRi (acquired resistance) (A2); non-fusion FGFR alteration(s) (B); or FGFR wild-type (FGFRwt, C). Primary endpoint was objective response rate (ORR) per RECIST version 1.1. Safety, PK parameters, and biomarker profile were evaluated and reviewed jointly with the efficacy outcomes. Adverse events (AEs) were graded per CTCAE version 5.0. Results: As of Sep 13, 2022, 25 pts with CCA were enrolled and dosed; 7 in A1, 6 in A2, 2 in B and 10 in C. Median age 61 [range 24-82] years old, 64% female, 93.3% had ≥ 3 prior treatment lines. 13 patients with ECOG 0 and 12 patients with ECOG 1 at baseline. Among 15 patients with historical FGFR alterations (13 fusions/rearrangement and 2 mutations), 93.3% had ≥ 1 prior FGFRi, and 3 pts (20.0%) had 2 prior FGFRi treatments. Eighteen pts were evaluable for tumor assessment at data cutoff date, including 4 in A1, 6 in A2, 1 in B and 7 in C. The median follow up was 15 weeks. In A2, 2 out of 6 pts (33%) achieved PR with tumor reductions of 34% and 54%. Overall DCR (CR or PR+SD) was 90% (9/10) in FGFR2 fusion/rearrangement pts; 100% in FGFR primary mutation pt (1/1); and 71% (5/7) in FGFRwt pts. One PR and 5 SDs lasted for more than 16 weeks. Among 25 treated pts, drug-related AEs occurred in 20 (80%) pts, including 7 (28%) with Grade (G) 1-2 AEs, 12 (48%) with G3 AEs, and 1 (4%) with G4 AE. Most frequently occurred G3/4 AEs were hypertension in 6 (24%) pts, including 5 (20%) with G3 and 1 (4%) with G4, G3 fatigue in 2 (8%) and G3 neutrophil count decreased in 2 (8%) pts. No drug-related G5 was observed. The efficacy and safety results observed were consistent with the previous reported data ( NCT03654547 ) in CCA pts. The preliminary biomarker analysis suggests loss of resistant FGFR mutation on liquid biopsy post tinengotinib therapy. Further biomarker analysis will be updated at the presentation. Conclusions: Tinengotinib may result in promising clinical benefit for CCA pts in the setting of FGFRi-resistance. Tinengotinib-related toxicities were manageable. An ongoing phase II study will further provide safety, efficacy and biomarker evaluations for both FGFR resistant and FGFRwt CCA. Clinical trial information: NCT04919642 .

507 Background: Lenvatinib, a multikinase inhibitor, is an FDA approved treatment for advanced hepatocellular carcinoma (HCC) in the first line setting. Atezolizumab and bevacizumab are considered new standard of care as first line therapy after results of the IMBrave 150 trial. Currently, we do not have data to suggest any second-line treatment after administration of immunotherapy. We describe the clinical outcomes in patients with advanced HCC who received lenvatinib following treatment with immunotherapy. Methods: We conducted a multicentric, retrospective analysis of patients with advanced HCC diagnosed between 2010 and 2021 at Mayo Clinic in Minnesota, Arizona, and Florida. The study was reviewed and approved by the intuitional review board. The primary outcomes were overall survival (OS) and progression free survival (PFS). Results: We identified 53 patients with advanced HCC who received lenvatinib following immunotherapy. Most patients (83%) were male. Median age at start of lenvatinib was 67 years old. Forty-two (79%) patients had a Child-Pugh score of A at diagnosis while 30 (58%) patients were still Child-Pugh A at time of lenvatinib initiation. Risk factors for HCC included Hep C (43%), alcohol use (34%), NASH (15%) and hepatitis B (7%). Forty-five (85%) patients received lenvatinib in the 2nd line and 8 (15%) patients received it as third line or later. At time of data extraction, 38 (72%) patients had died. Median PFS was 4 months (95% CI: 3 – 6) and median OS from time of lenvatinib initiation was 13 months (95% CI: 6 – 24). The most common adverse events of any grade included fatigue (53%), hypertension (37%), AST elevation (30%), anorexia (28%), bilirubin elevation (25%) and diarrhea (25%). Twenty-one (40%) patients experienced grade 3 or higher adverse events including hypertension (25%), confusion (6%), acute kidney injury (2%), hyperkalemia (2%), ALT elevation (2%), proteinuria (2%), arthralgia (2%), heart failure (2%), AST elevation (2%), bilirubin elevation (2%), palmar-plantar erythrodysesthesia (2%), oral mucositis (2%), weight loss (2%), hypothyroidism (2%), anorexia (2%), fatigue (2%) and diarrhea (2%). Seven patients stopped treatment due to adverse events: 1 for hypertension, 2 for confusion, 1 for heart failure, 2 for fatigue, and 1 for elevated bilirubin. Conclusions: The optimal sequencing of therapy for patients with advanced HCC following progression on immunotherapy remains unknown. We found that median OS was 13 months in patients who received lenvatinib after immunotherapy which is comparable to survival in other studies when used as first line therapy. Our experience demonstrates that patients may benefit from treatment with lenvatinib following initial progression on immunotherapy.