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1410 citation(s) found for "Ha, Christina".

P-1498. Contezolid is Active against Methicillin-Resistant Staphylococcus aureus in Experimental Rat Foreign Body Osteomyelitis
Karau, Melissa J. , Koscianski, Christina, Greenwood‐Quaintance, Kerryl E. , Mandrekar, Jay , Herren, Sebastian , Patel, Robin

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.1667 Get It

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of orthopedic implant-associated infection, where S. aureus can survive intracellularly and form biofilms. Vancomycin has poor activity against staphyloccoccal biofilms. Although rifampin is effective against staphylococcoal biofilms and has intracellular activity, resistance may develop when it is used as a single agent. Contezolid is a novel oxazolidinone with reported activity against S. aureus in vitro and in vivo in both murine systemic and thigh infection models. Here, we assessed the in vivo activity of contezolid, with and without rifampin, in a rat model of foreign body osteomyelitis. Figure 1. Quantities of MRSA IDRL-6169 recovered from A. tibia B. K-wire. Circles represent values from individual animals; horizontal lines represent mean values. Compared to no treatment: *p=0.0186 **p<0.0002 Methods The left tibia of 60 male Wister rats were inoculated with arachidonic acid (sclerosing agent) and 106 cfu MRSA IDRL-6169 and a K-wire implanted. After four weeks, rats received either no treatment, contezolid (50 mg/kg orally, every 12 h), rifampin (10 mg/kg intraperitoneally every 12 h), rifampin plus contezolid, or vancomycin (75 mg/kg intraperitoneally, every 12 h) plus rifampin for 21 days. Following treatment, tibiae were harvested and cyropulverized. Tibiae and K-wires were cultured separately, and results reported as log10 cfu/gram of bone or K-wire (limit of detect 0.1 log10), respectively. Wilcoxon rank-sum test and false discovery rates were performed and p< 0.05 considered significant. Results Results are shown in Figure 1. MRSA was recovered from tibiae and K-wires of all untreated animals, at means of 5.1 log10 cfu/bone and 3.0 log10 cfu/K-wire, respectively. There was a 1.0 log10 cfu/g mean reduction in MRSA recovered from the tibiae of contezolid-treated rats compared to untreated rats (p=0.0186), and a 0.2 log10 reduction on K-wires. No MRSA was recovered from the tibiae or K-wires in animals receiving rifampin, whether alone or in combination with contezolid or vancomycin. Conclusion Contezolid was active against MRSA in a rat model of foreign body osteomyelitis, reducing bacterial loads in bone, albeit not on K-wires, unless co-administered with rifampin. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria
P-1152. Cefepime, Meropenem, and Piperacillin Therapeutic Drug Monitoring in Neonatal and Pediatric Patients
Dinnes, Laura , Ristagno, Elizabeth H. , Stetson, Raymond C. , Lee, Grace , Smith, Brandi, Thurber, Gregory, Gullickson, Taylor, Frazee, Erin N. , Brumbaugh, Jane E. , Levy, Emily R. , Rivera, Christina G.

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.1338 Get It

Abstract Background Pharmacokinetics of beta-lactams vary widely in neonatal and pediatric patients due to developmental biology and critical illness. Cefepime (FEP), meropenem (MEM), and piperacillin/tazobactam (TZP) are highly susceptible to pharmacokinetic changes as hydrophilic, small molecules with renal clearance. Subtherapeutic levels are associated with clinical and microbiologic failure, and supratherapeutic levels associated with toxicity. Beta-lactam therapeutic drug monitoring (TDM) may optimize the effectiveness and safety of these agents. The purpose of this investigation is to describe the % of pediatric and neonatal patients with beta-lactam serum levels within target range. Methods In August 2023, TDM launched at the Mayo Clinic Children’s Center for select patients treated with FEP, MEM, or TZP with expected durations ≥ 48 hours, or who were on kidney replacement therapy (KRT), extracorporeal membrane oxygenation (ECMO), weighed > 120 kg, had a BMI > 95th percentile, or at the discretion of pediatric ID team. Validated drug assays were performed daily, Monday through Friday. A two-level sampling strategy was preferred with a peak 1 hour after the end of the infusion and a trough 30 minutes before the next dose. Empiric trough target ranges were set at FEP 8-50 mg/L, MEM 2-30 mg/L, and piperacillin 16-150 mg/L. These target ranges were adjusted with confirmed microbiology to a time above the minimum inhibitory concentration of the organism for 100% of the dosing interval (100%T > MIC). Results From August 2023 to April 2024, 74 episodes of TDM were performed on 45 patients. Thirty-seven (82%) patients were in an intensive care unit (ICU) at the time of TDM, 8/45 (22%) of whom were in the neonatal ICU. Target range was achieved in 67% of patients on FEP, 50% on MEM, and 52% on TZP. Median (IQR) trough values were 22.1 (8.6, 44.2) mg/L for FEP, 0.6 (0, 4.1) mg/L for MEM, and 15.5 (3.8, 27.1) mg/L for TZP. Seven levels were above target for FEP and 0 for MEM and TZP. Seven levels were below target for FEP, 4 for MEM, and 11 for TZP. Conclusion Implementation of a TDM program for FEP, MEM and TZP in pediatric and neonatal patients revealed drug levels frequently outside target range. TDM may facilitate dose individualization to optimize medication efficacy and minimize toxicity. Disclosures Raymond Stetson, MD, MS, Moderna: Grant/Research Support Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Board Member Erin F. Barreto, PharmD, MSc, Baxter Health: Advisor/Consultant|Wolters Kluwer: Advisor/Consultant
P-291. Whole genome sequencing (WGS) demonstrates high relatedness between carbapenemase-producing Klebsiella pneumoniae isolates cultured from paired rectal swab and blood specimens among hospitalized patients in Greece
Banerjee, Ritu , Greenwood‐Quaintance, Kerryl E. , Koscianski, Christina, Starkey, Jordan, Rodning, Amanda A, Sereni, Zoe, Trikoupis, Petros, Oikonomou, Margarita, Kousouli, Elisavet , Roussou, Anna , Charami, Smaragdi, Rovatsou, Alexandra, Louka, Christina , Mamali, Vasiliki , Chrysos, Georgios , Baziotis, Georgios Alexandros , Vourli, Sophia , Louka, Styliani, Poulianou, Eleni, Zarkotou, Olympia , Skoura, Lemonia , Banerjee, Ritu , Patel, Robin , Mantzana, Paraskevi , Tychala, Areti , Meletis, Georgios , Sereni, Zoe, Roussou, Anna, Georgiou, Panagiota Christina , Karakosta, Polyxeni , Protonotariou, Efthymia , Pournaras, Spyros

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.494 Get It

Abstract Background Intestinal colonization with carbapenem-resistant organisms (CRO) may be considered to inform empiric antibiotic selection for symptomatic infection. However, it is unclear how often gut colonizing CRE isolates are related to bloodstream isolates in hospitalized patients with bacteremia, especially in areas with high CRO prevalence. Minimum spanning tree of isolate relatedness Isolates and corresponding patient number (P1-P6) and rectal (R) or blood (B) specimen are noted within circles and allelic differences are numerated on linking lines between the circles. Group 1 and 3 isolates are possibly related to each other. Created with BioRender.com. Methods Patients with paired K. pneumoniae carbapenemase (KPC)-producing K. pneumoniae isolates cultured from surveillance rectal specimens and clinically collected blood specimens collected within 1-8 days of each other between 2019-2023 were identified at 3 Greek hospitals. Isolates were frozen and shipped to a reference laboratory in the U.S for whole genome sequencing (WGS) using Illumina MiSeq. Assembly and core genome multilocus sequence typing (cgMLST) analysis were performed with Ridom SeqSphere+ software. Isolate relatedness was based on the total number of allelic differences between each isolate: < 15, related; 16-50, possibly related; ≥ 51, unrelated. Results One hundred eight paired isolates were identified from 54 unique patients; 6 pairs and 12 total isolates underwent cgMLST. In 5 of 6 pairs (83%), the rectal isolate was collected prior to the bloodstream isolate. Rectal and bloodstream isolates were related to one another in 5 of 6 (83%) pairs and were unrelated in 1 pair. Two pairs collected from 2 distinct patients admitted to the same intensive care unit (patients 2 and 3, Figure) were possibly related (16-50 allelic differences) to each other. Conclusion In this pilot evaluation conducted in a setting of high CRO prevalence, KPC-producing K. pneumoniae isolated from paired rectal and blood specimens from individual patients were often related to each other, suggesting that intestinal colonization by this organism could inform empiric antibiotic treatment for bacteremia. Two patients from the same hospital unit had isolates that were possibly related, suggesting within hospital transmission. WGS is a powerful tool that can inform clinical and infection control practices. WGS of the remaining K. pneumoniae pairs and additional Acinetobacter baumannii pairs is ongoing. Disclosures Robin Patel, MD, I already disclosed so please pull from disclosure for other abstracts: Advisor/Consultant|I already disclosed so please pull from disclosure for other abstracts: Grant/Research Support|I already disclosed so please pull from disclosure for other abstracts: Honoraria
P-2225. Interactions between phage and host bacteria in immunized rabbit serum
Karau, Melissa J. , Koscianski, Christina, Christensen, Trace , Herren, Sebastian , Patel, Robin

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.2379 Get It

Abstract Background Phage therapy is being evaluated to treat bacterial infections. Host-related factors that might abrogate phage efficacy remain incompletely characterized. Phage aggregation has been hypothesized to protect phages in harsh environments. Herein, effects of immunized rabbit sera on phage aggregation were assessed. Methods Three New Zealand rabbits were immunized weekly for 3 weeks by intramuscular injection of phage K. Serum samples were collected weekly at times 0, 7, 14, 21 and 28. Development of an antibody response was confirmed by ELISA. Phage K was exposed to immunized serum with or without heat-inactivated host bacterium (Staphylococcus aureus ATCC 19685) as follows. 45 µl of phage K (1010±1 plaque forming units/mL [pfu/ml]) was mixed with 5 µl immunized serum diluted 1:1000 with or without heat-inactivated bacterial host in phosphate buffered saline (PBS). After incubation, exposed phage was visualized using transmission electron microscopy (TEM, JEOL) at 80kV. Results Phage K immunization elicited a strong IgG response. Exposure to immunized serum led to a decrease in viable phage over time, abrogated by adding heat-inactivated bacteria (Fig 1). TEM imaging showed phage clustering with exposure to immunized serum (Fig 2A); clusters appeared disorganized with concomitant exposure to heat-inactivated host bacteria (Fig 2B). Exposure of phage to heat-inactivated bacteria without serum yielded evenly distributed phage, with minimal clustering (Fig 2C). Conclusion Phage K exposure elicited a neutralizing immune response associated with decreased phage survival in immunized serum, prolonged by adding heat-inactivated host bacteria. TEM imaging showed phage K clustering in different ways depending on the microenvironment encountered. Biological relevance and mechanistic underpinnings of these phenomena need further characterization. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria
P-2021. How Have COVID-19 Treatment Guidelines and the Scientific Evidence Evolved throughout the Pandemic and Endemic Eras?
Mozaffari, Essy, Loubet, Paul, Rawal, Aaditya , Kaiser, Emily , Nicolae, M, Polyakova, Olena, Oppelt, Thomas F , Chiang, Mel, Sax, Paul E. , Bartoletti, Michele , Amin, Alpesh , Doi, Yohei , Loubet, Paul , Rivera, Christina G. , Roshon, Michael J. , Polyakova, Olena, Kalil, André C.

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.2178 Get It

Abstract Background With progressive understanding of the natural history of COVID-19 and accumulation of knowledge on clinical management, treatment guidelines recommended several options including remdesivir (RDV), a broad-spectrum antiviral. Given the evolving nature of COVID-19, it is critical to capture the totality of scientific evidence to inform clinical decision making. We conducted a systematic literature review (SLR) to summarize the mortality endpoint for RDV among hospitalized adults throughout COVID-19 eras and contrasted with evidence informing treatment recommendations in clinical guidelines. Methods We systematically searched MEDLINE, Embase and Cochrane Library databases for interventional and observational studies examining RDV efficacy. Clinical trial registries, Cochrane COVID-19 Study Register, and conference abstracts were hand-searched (Fig1). Case reports and case studies were excluded. A review of most recent RDV recommendations across guidelines was conducted. Results From Dec ’19 to Dec ’22, 123 relevant publications were identified. In ’23, the evidence grew significantly, with 70 new publications. In total, 193 publications were evaluated, and 122 unique studies were included. While early randomized clinical trials (RCT) and small sample size observational studies did not universally demonstrate a significant difference in mortality in all severity groups of RDV-treated patients, real-world studies with larger sample sizes showed a significant impact across disease severity levels, regardless of COVID-19 era (Table1). Guideline recommendations for COVID-19 treatment with RDV are based on early RCTs (Table2) and most have not been updated (Fig2). Conclusion Our comprehensive evaluation of scientific literature indicates that evidence of RDV impact on mortality in hospitalized COVID-19 patients continued to grow and cover full range of disease severity. Guideline recommendations have not evolved in parallel which may explain differing recommendations in certain subgroups (e.g. IMV/ECMO). To assure that providers in the hospital setting are aware of and deploy evidence-based optimal care for patients with COVID-19, recommendations should rely on current evidence, including real-world data. Disclosures Essy Mozaffari, PharmD, MPH, MBA, Gilead Sciences, Inc.: Employee|Gilead Sciences, Inc.: Stocks/Bonds (Public Company) Michele Bartoletti, MD, PhD, Advan pharma: Advisor/Consultant|Advan pharma: Honoraria|Biomereux: Honoraria|Gilead: Advisor/Consultant|Gilead: Honoraria|Infectopharma: Advisor/Consultant|Msd: Advisor/Consultant|Msd: Grant/Research Support|Msd: Honoraria|Pfizer: Honoraria Alpesh N. Amin, MD, MBA, Alexion: Advisor/Consultant|Aseptiscope: Advisor/Consultant|AstraZeneca: Advisor/Consultant|Bayer: Advisor/Consultant|Dexcom: Advisor/Consultant|Eli Lilly: Advisor/Consultant|Ferring: Advisor/Consultant|Gilead: Advisor/Consultant|GSK: Advisor/Consultant|Heartrite: Advisor/Consultant|Nova Nordisk: Advisor/Consultant|Pfizer: Advisor/Consultant|Renibus: Advisor/Consultant|Reprieve: Advisor/Consultant|Salix: Advisor/Consultant|Seres: Advisor/Consultant|Spero: Advisor/Consultant Yohei Doi, MD, PhD, bioMerieux: Lecture fees|Entasis: Grant/Research Support|Fujifilm: Advisor/Consultant|Gilead Sciences: Advisor/Consultant|GSK: Advisor/Consultant|KANTO CHEMICAL CO.,INC.: Grant/Research Support|KANTO CHEMICAL CO.,INC.: Patent for genotyping kit|MeijiSeika Pharma: Advisor/Consultant|Moderna: Advisor/Consultant|MSD: Lecture fees|Pfizer: Advisor/Consultant|Shionogi & Co., Ltd.: Grant/Research Support|Shionogi & Co., Ltd.: Lecture fees Paul LOUBET, MD, PhD, Astrazeneca: Advisor/Consultant|Gilead: Advisor/Consultant|Moderna: Advisor/Consultant|Pfizer: Advisor/Consultant Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Board Member Michael Roshon, MD/PhD, MD/PhD, Gilead: Honoraria Thomas F. Oppelt, PharmD, BCPS, Gilead Sciences, Inc: I am an employee of Gilead Sciences, Inc|Gilead Sciences, Inc: Stocks/Bonds (Public Company) Mel Chiang, Ph.D., Gilead Sciences: I am an employee of Gilead Sciences|Gilead Sciences: Stocks/Bonds (Public Company)
646. Clinical and microbiological outcomes of omadacycline for pulmonary Mycobacterium abscessus complex
Vemula, Raaga, Mammadova, Mehriban, Wadle, Carly , Muscarella, Anahit, Cimino, Christo , Zeuli, John D. , Howard, Catessa, Butt, Saira , Ong, Aaron, Kaip, Emily A, Tupayachi-Ortiz, Maria G., Fiske, Christina T. , Judd, Chloe, Caniff, Kaylee E , Rybak, Michael J. , Musawa, Mohammed Al , Mejía-Chew, Carlos , Hamad, Yasir , Cohen, Keira A. , Judd, Chloe

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.211 Get It

Abstract Background Mycobacterium abscessus complex (MABC) is a difficult-to-treat infection due to antibiotic resistance. Our study aimed to assess omadacycline’s (OMC) clinical and microbiological outcomes for the treatment of pulmonary MABC. Methods A retrospective study was carried out across 12 US medical institutions from 1/2018-4/2023 to examine the clinical outcomes, and tolerability of OMC treatment for pulmonary MABC. Patients aged ≥ 18 years who were treated with OMC for ≥ 3 months were included. The primary outcome was clinical success at 3, 6, and 12 months. The secondary outcomes were sputum culture conversion rate, adverse effects, and clinical success by subspecies and macrolide susceptibility. Results Thirty-five patients were included in this analysis. Most patients were female (74.3%) and Caucasian (74.3%), with a median (IQR) age of 61 years (51–70). Subspeciation was performed for 22 isolates with predominant M. abscessus subspecies (77.3%). Moreover, coinfection with other NTM species was present in 28.6% of cases where Mycobacterium avium complex was present in 8 cultures. Sixty-eight percent of the MABC isolates were confirmed to be macrolide resistance; half (12/24, 50.0%) were evident by the presence of functional erm gene, while the other half by antimicrobial susceptibility (Table 3). Of the remaining isolates, 14% were macrolide-susceptible, while no information was reported in 17%. The median (IQR) treatment duration of OMC was 8 months (3.9 – 15.7). The most commonly co-administered antibiotics were intravenous amikacin, imipenem/cilastatin, inhaled amikacin and clofazimine with the same percentage (42.9%) (Table 1). Overall, MABC clinical success was observed in 71.4%, 89.7%, and 90.9% in 3-, 6- and 12 months, respectively (Table 3). Adverse effects reported in 34.3%. The most common side effects were gastrointestinal intolerance (25.7%) and hepatoxicity (11.4%), which led to drug discontinuation in 22.9%. Conclusion OMC treatment showed clinical success in > 70% of patients with pulmonary MABC including patients with macrolide resistant strains for more than 3 months. However, larger studies are needed to validate the outcomes beyond 12 months. Disclosures Kaylee E. Caniff, PharmD, BCIDP, T2Biosystems: Honoraria Michael J. Rybak, PharmD, PhD, MPH, Abbvie, Melinta, Sionogi, Merck, T2Biosystems: Advisor/Consultant|Abbvie, Melinta, Sionogi, Merck, T2Biosystems: Grant/Research Support|Abbvie, Melinta, Sionogi, Merck, T2Biosystems: Speaker
P-1666. Hematology-Oncology Unit-Specific Antibiogram: A Decade of Experience at a Large Academic Medical Center
Cole, Nicolynn C., Estes, Lynn L., Clement, Josh , Rivera, Christina G. , Schuetz, Audrey N.

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.1832 Get It

Abstract Background Antibiograms are an important stewardship tool that can inform optimal empiric therapy; most antibiograms are hospital-wide. Unit-specific antibiogram data for unique patient populations including intensive care unit and pediatrics is robust; however, published experience with unit-specific antibiograms in the hematology-oncology (heme-onc) population is limited. These patients are unique because of the common use of antimicrobial prophylaxis, prolonged broad-spectrum antibiotics, and an immunocompromised state. We sought to examine the trends in antibiogram antimicrobial susceptibility over time. Methods This retrospective quality initiative included microbiology results (first isolates per patient per timeframe) from Mayo Clinic Rochester from 2012 to 2022. Eligible cultures were those identified as being obtained from one of 8 hematology, oncology, or bone marrow transplant inpatient units. Agar dilution susceptibility testing and Clinical and Laboratory Standards Institute (CLSI) breakpoints were used. Screening PCRs (eg, VRE PCR) were excluded. Culture and susceptibilities were identified by an EMR based report, compiled annually, and reported for two-year periods. Susceptibility rates were compared using the Chi-square test and Chi-square analysis for trends. Results There were 4 gram-negative and 5 gram-positive organism groups that met CLSI antibiogram criteria of ≥ 30 isolates and were included (tables 1-4). There were several significant differences in comparison to the hospital-wide antibiogram, with lower antibiotic susceptibility rates in the heme-onc units for multiple organisms, notably fluoroquinolones to E.coli and P. aeruginosa and several cephalosporins to Enterobacterales as well as penicillin and levofloxacin to Viridans group Streptococcus and vancomycin to E. faecium (tables 1&2). Over the period of 2012-2013 to 2021-2022, susceptibility rates remained stable among the heme-onc antibiogram, with few significant changes (tables 3&4). Conclusion Heme-onc antibiograms illustrated susceptibility rate differences compared to our hospital-wide antibiograms, particularly for antimicrobials used as prophylaxis. Through population-specific antibiograms, providers may be able to improve empiric antibiotic selection. Disclosures Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Board Member
Impact of baseline alterations in HER2-pathway oncogenic drivers on response to anti-HER2 therapy in patients (pts) with HER2-amplified advanced colorectal cancer (aCRC).
Hoyek, Celine , Pirozzi, Angelo , Zheng-Lin, Binbin , Ramaker, Ryne C. , Ahn, Daniel H. , Abidoye, Oluseyi , Eslinger, Cody , Nakamura, Yoshiaki , Sonbol, Mohamad Bassam , Wu, Christina N. , Borad, Mitesh J. , Ikeda, Masafumi , Shibuki, Taro , Yoshino, Takayuki , Strickler, John H. , Bekaii‐Saab, Tanios

Journal of Clinical Oncology | January 27, 2025 | Volume: 43 | Issue: 4_suppl | Pages: 243-243

10.1200/jco.2025.43.4_suppl.243 Get It

243 Background: HER2-amplified aCRC is associated with poor prognosis despite new anti-HER2 regimens. Insight on biomarkers that predict response to these therapies is limited. This study aims to evaluate whether baseline alterations in oncogenic drivers along the HER2 pathway predict response to anti-HER2 therapy in HER2-amplified aCRC. Methods: In this international multi-center study involving Mayo Clinic, Duke Cancer Institute and National Cancer Center Hospital East (Japan), we collected baseline genomic alterations from tissue or blood samples using next-generation sequencing (NGS) prior to anti-HER2 therapy initiation. We defined PIK3CA, RAS, RAF, MAP2K, and MET as oncogenic drivers of resistance within the HER2 pathway. Overall survival (OS) was evaluated with the Kaplan-Meier method and a log-rank test was used to compare median OS (mOS) between pts with and without alterations in the above genes. A chi-square test (significance level 0.05) was performed to compare overall response rate (ORR) and disease control rate (DCR). Results: We identified 39 pts with HER2-amplified aCRC and baseline NGS. Median age was 57 (range 30-77), 54% were male. Baseline alterations in HER2 pathway oncogenic drivers were identified in 17 pts (43.5%). 18 (46%) received monoclonal antibodies (mAbs) plus tyrosine kinase inhibitors, 12 (30%) received dual mAbs and 7 (18%) received trastuzumab deruxtecan. The mOS was 41.9 months (mos) (95%CI 23.7-60.1) for other alterations vs 24.2 mos (95%CI 14.1-34.3) in pts with HER2 pathway alterations (p = 0.1). ORR was 47% vs 41% (p = 0.7) and DCR 82% vs 73% (p = 0.4), for pts with HER2 pathway alterations and without HER2 pathway alterations, respectively. 4 pts receiving trastuzumab/tucatinib had complete response, none of which had HER2 pathway alterations. Conclusions: Pts with baseline alterations in oncogenic drivers of the HER2 pathway had clinically worse outcomes compared to pts without such alterations despite receiving HER2-targeted therapy, though results lacked statistical significance. Larger studies are needed to confirm the lack of benefit from anti-HER2 therapy in this subgroup.
Neoadjuvant immunotherapy and nonoperative management of dMMR gastroesophageal adenocarcinoma (GEA): A retrospective case series.
Sahwan, Oudai , Ahn, Daniel H. , Jamal, Fares , Borad, Mitesh J. , Bekaii‐Saab, Tanios , Wu, Christina , Sonbol, Mohamad Bassam

Journal of Clinical Oncology | January 27, 2025 | Volume: 43 | Issue: 4_suppl | Pages: 451-451

10.1200/jco.2025.43.4_suppl.451 Get It

451 Background: Perioperative chemotherapy with surgery is the standard of care for patients (pts) with resectable gastric or gastroesophageal junction adenocarcinoma (GEA). However, recent studies have shown more favorable responses after neoadjuvant immunotherapy (NIO) in patients with mismatch repair deficient (dMMR) cancers. Herein, we present the outcomes of 10 cases with dMMR GEA. Methods: We retrospectively reviewed patients with GEA at Mayo Clinic Arizona who met the following criteria: have dMMR disease by IHC, nonmetastatic operable disease, and received NIO +/- chemotherapy. Patient demographics, disease characteristics, and clinical outcomes were extracted. The primary endpoint was clinical complete response (cCR) in patients treated with non-operative management (NOM) defined as complete radiological response and no residual disease on endoscopic ultrasound (EUS) and biopsy. Results: 10 pts with dMMR GEA with a median age of 70 (43-85) were identified. 6 pts had T2N0, 1 had T4N0, 3 had N+ disease. 8 pts received NIO monotherapy upfront, 1 received NIO after progressing on chemotherapy, and 1 concurrently with chemotherapy. No grade 3/4 toxicities were reported, however, 2 pts discontinued therapy due to arthralgia and colitis. After NIO, 9/10 pts had significant or complete resolution of FGD avidity on PET/CT, while 1/10 had stable disease. 3/10 pts underwent surgical resection, with 2 achieving pathological complete response (pCR) and the third showing T1N0 disease with no recurrence 1 year after surgery. Notably, one of the pts with pCR passed away due to surgical complications. 7/10 patients had NOM, of whom, 4 had cCR and 3 had radiological response only, as no EUS data was available. 4/7 NOM pts had follow up data at 6 months with no evidence of progression, of whom one pt remained progression-free at 33 months. ctDNA testing was performed in 6/10 pts: 2 had undetectable ctDNA at baseline, while 3 became MRD-negative after NIO, consistent with radiological and/or pathological response, and 1 had persistent ctDNA both before and after NIO, despite cCR. Conclusions: This study demonstrates exceptional and prolonged response, along with good tolerability to NIO in pts with dMMR GEA, supporting the feasibility of non-operative management in such patients.
A global comparative study on real-world clinical and genomic differences in advanced biliary tract cancer.
Hoyek, Celine , Zheng-Lin, Binbin , Morizane, Chigusa, Ahn, Daniel H. , Roberts, Lewis R. , Roberts, Lewis R , Abidoye, Oluseyi , Kosiorek, Heidi , Eslinger, Cody , Sonbol, Mohamad Bassam , Wu, Christina , Tran, Nguyen H., Babiker, Hani M. , Yoshino, Takayuki , Ikeda, Masafumi , Morizane, Chigusa , Bando, Hideaki , Nakamura, Yoshiaki , Fujisawa, Takao , Shibuki, Taro , Borad, Mitesh J. , Bekaii‐Saab, Tanios

Journal of Clinical Oncology | January 27, 2025 | Volume: 43 | Issue: 4_suppl | Pages: 628-628

10.1200/jco.2025.43.4_suppl.628 Get It

628 Background: Biliary tract cancers (BTC) are aggressive malignancies with poor survival outcomes and limited treatment options. This study compared the epidemiological and molecular differences of advanced BTC patients through a global collaboration involving the Mayo Clinic and National Cancer Center Hospital East. Methods: We included patients with advanced BTC who underwent comprehensive tumor molecular profiling who received at least 30 days of systemic therapy. Patients were grouped based on specific alterations. Overall survival (OS) was calculated from the start of first-line therapy until death and compared among subgroups using Cox regression models. Results: 332 (36%) out of 932 patients had at least one actionable mutation : somatic BRCA1/2 mutations N=106, FGFR2 fusions N=61, HER2 amplifications N=65, KRAS G12C/D mutations N=46, IDH1 mutations N=38, and TMB >10 mut/Mb N=16. BRCA1/2 -mutated BTC were more commonly found in older Asian males with intrahepatic tumors and often presented with peritoneal and liver metastases upon initial diagnosis. FGFR2 fusions were more prevalent in younger White females with intrahepatic tumors, while HER2 amplifications were mainly seen in Asian females with gallbladder tumors. KRAS mutations were primarily observed in Asian males, and IDH1 mutations were common in White males with intrahepatic tumors, frequently presenting with liver metastasis. Survival outcomes varied significantly based on the alteration type: patients with FGFR2 fusions had the longest median OS (mOS) at 23.3 months (mo) (95%CI 18.4-34.9), followed by those with IDH1 mutations (19.3 mo; 95% CI 17.4-NE) and TMB >10 mut/Mb (17.8 mo; 95% CI 13.6-NE). BRCA mutations had a mOS of 16 mo (95% CI 14.6-19.8), while HER2 amplifications and KRAS mutations had mOS of 15.5 (95% CI 11.9-20.2) and 11.6 mo (95% CI 10.0-20.9), respectively. Conclusions: These findings underscore the heterogeneity in clinical and genomic characteristics among BTC patients, highlighting the importance of tailored therapeutic approaches. Baseline patient characteristics stratified by mutation status. KRAS G12C/D (N=46) BRCA 1/2 (N=106) IDH1 (N=38) HER2 amplification(N=65) FGFR2 fusion(N=61) TMB>10 mut/Mb(N=16) P-value Median Age, year 67 68 64 66 52 73 <0.001 Female, n (%) 19 (41) 34 (32) 18(47) 34 (52) 45(74) 6 (38) <0.001 Race, n (%) <0.001 Asian 31 (67) 97 (92) 13 (34) 51 (79) 10 (16) 6 (38) White 14 (30) 8 (8) 24 (63) 13 (20) 48 (79) 10 (63) Primary tumor location, n (%) <0.001 Intrahepatic 28 (68) 45 (45) 33 (100) 19 (31) 54(95) 10 (67) Extrahepatic 9 (22) 27(27) 0 (0) 10 (16) 2 (4) 4 (27) Gallbladder 4 (10) 28 (28) 0 (0) 32 (53) 1 (2) 1 (7) Sites of Metastasis at diagnosis, n (%) Abdominal Wall / Peritoneal 9 (24) 15 (19) 4(13) 7 (12) 6 (10) 4 (27) 0.309 Bone 33 (92) 70 (90) 26 (87) 2 (3) 9(15) 0 (0) 0.212 Liver 20 (49) 52 (61) 28 (82) 45 (73) 45 (76) 6 (38) 0.001 Lung 26 (70) 65 (82) 22 (69) 36 (58) 27(45) 11 (69) 0.006