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761 Background: Glycogen Synthase Kinase-3β (GSK-3β) is a known therapeutic target in cancer including pancreatic adenocarcinoma (PDAC). The combination of elraglusib (9-ING-41), a novel GSK-3 inhibitor, and gemcitabine/nab-paclitaxel (GnP) is being evaluated as first-line therapy for patients with metastatic PDAC (mPDAC). We previously reported topline results indicating that the 1801 Part 3B phase 2 trial (NCT03678883) met its primary endpoint, showing a clinically meaningful survival benefit in patients treated with elraglusib/GnP compared to GnP alone. Here, we examined whether gene mutations correlated with clinical outcomes in mPDAC patients enrolled in this randomized phase 2 trial. Methods: For mutational analysis, archival tumor and/or plasma samples were obtained from 53 (GnP group) and 117 (elraglusib/GnP group) patients with previously untreated mPDAC. Cell-free DNA and/or tumor-extracted DNA were analyzed using the next generation sequencing. The comparison of the response rates was performed with the use of Chi-square tests. Kaplan-Meier survival curves were compared by log-rank (Mantel-Cox) tests. Results: Mutational analysis identified frequently mutated genes (detectable in ≥25% of patients): KRAS (141/170, 83%), TP53 (121/170, 71%), and CDKN2A (56/170, 33%). Mutations in KRAS, TP53, or CDKN2A genes did not correlate with objective response rate. Based on 81% of the recorded death events in the elraglusib/GnP group and 91% in the GnP group (topline data April, 2025), KRAS and TP53 gene mutations were associated with worse overall survival (OS) in patients treated with elraglusib/GnP (p<0.05) but not in GnP-treated patients. The rate of triple (KRAS+TP53+CDKN2A) mutations was significantly higher in the patients with OS<2 months as compared to the patients with OS>2 months in the elraglusib/GnP group (p<0.05) but not in the GnP group. Conclusions: Our preliminary results identified KRAS and TP53 gene mutations as potential predictive biomarkers of clinical outcome in elraglusib/GnP-treated mPDAC patients. Updated OS data and mutational analysis will be included in the final presentation. Clinical trial information: NCT03678883 .

707 Background: Due to insufficient data, therapy for unresectable, locally advanced pancreatic adenocarcinoma (LAPAC) is based on trials in metastatic disease, and outcomes remain poor. TTFields disrupt cancer cell division using alternating low-frequency electric fields delivered externally by a portable device. In the phase 3 PANOVA-3 trial (NCT03377491), TTFields with gemcitabine/nab-paclitaxel (GnP) significantly improved overall survival (OS; HR 0.82) and pain-free survival (HR 0.74) vs GnP in patients with unresectable LAPAC. Methods: In PANOVA-3, patients with newly diagnosed LAPAC were randomized 1:1 to receive GnP with or without concomitant TTFields. Kaplan-Meier methodology was used for time-to-event analyses. Response evaluations were based on RECIST V1.1. OS, pain-free survival, and safety were analyzed post-hoc in subgroups based on sex (male, female), age ( < 65, ≥65 years), and BMI (<25, ≥25 kg/m 2 for efficacy; ≤20, 20–25, 25–30, ≥30 kg/m 2 for safety). Differences between treatment arms were compared using the log-rank test. Results: Efficacy outcomes are shown in the table. TTFields significantly extended pain-free survival in females and patients ≥65 years. Device-related adverse events (AEs) were comparable between sexes, older and younger patients, and across BMI ranges. Some device-related skin adverse events occurred more frequently in females (e.g. dermatitis, 33.1% vs 22.7%; rash 21.8% vs 13.5%, females vs males, respectively); others occurred more often in males (e.g. maculo-papular rash, 9.8% vs 14.2%; erythema, 9% vs 12.1%, females vs males, respectively). Dermatitis and pruritus had a higher incidence in the BMI ≥30 kg/m 2 subgroup (38.5%), whereas patients with BMI <30 kg/m 2 did not show noticeable differences in device-related AEs. Skin irritation (11.5% vs 5.5%) and skin reactions (8.5% vs 2.8%) were more common in patients ≥65 years than patients <65 years. Conclusions: Median OS and pain-free survival in these post-hoc subgroup analyses are generally consistent with the overall analysis, supporting use of TTFields with GnP in unresectable LAPAC. No new safety concerns were noted; observations were consistent with the general PANOVA-3 population. Clinical trial information: NCT03377491 . Survival outcomes for the subgroup analyses. Median OS, months TTFields + GnP GnP P value Age<65 years≥65 years 18.6 (n=113)15.4 (n=172) 16.0 (n=114)12.9 (n=172) 0.2060.061 SexFemaleMale 16.8 (n=138)15.7 (n=147) 14.5 (n=161)13.4 (n=125) 0.1140.145 BMI<25≥25 16.7 (n=166)16.2 (n=117) 14.2 (n=174)14.5 (n=108) 0.1550.105 Median pain-free survival, months Age<65 years≥65 years 16.5 (n=113)13.1 (n=172) 9.2 (n=114)8.3 (n=172) 0.4070.035 SexFemaleMale 16.5 (n=138)15.2 (n=147) 8.3 (n=161)9.3 (n=125) 0.0260.478 BMI<25≥25 16.6 (n=166)14.7 (n=117) 9.1 (n=174)8.3 (n=108) 0.1170.088

653 Background: Elraglusib (9-ING-41), a novel small molecule inhibitor of GSK-3ß, has a multimodal mechanism of action that enhances chemotherapy cytotoxicity and regulates anti-tumor immune cell response. Elraglusib was evaluated in a randomized, open-label, phase 2 study (NCT03678883) comparing elraglusib/GnP vs GnP in previously untreated mPDAC. Methods: Pts were randomized 2:1 to GnP plus elraglusib 9.3 mg/kg IV once weekly or GnP. Primary endpoint was mOS, with 1-yr OS rate estimates summarizing clinical benefit throughout the study. Secondary endpoints were ORR, mPFS, and TEAEs/TRAEs. Pre-dose cytokines, mutational analysis, and immunophenotyping were correlated with outcomes. An oral presentation at ASCO 2025 discussed preliminary data. Results: As of 27 April 2025, the primary analysis set included 155 pts in the elraglusib/GnP arm and 78 pts in the GnP arm, with 52.8% males and 57.5% ECOG PS 1. The 1-yr OS rate was 44.1% with elraglusib/GnP vs 22.3% with GnP; the mOS was 10.1 mo with elraglusib/GnP vs 7.2 mo with GnP (HR, 0.62; p=0.01) with approximately 79% events recorded (25.8% of pts on elraglusib/GnP and 10.3% on GnP were censored with the majority at >12 mo OS). Improved OS with elraglusib/GnP was consistent across all randomized pts and subgroups regardless of liver metastases, ECOG status, or baseline CA 19-9 levels. Most common TRAE with elraglusib/GnP was grade 1-2 transient visual impairment (66.5% pts vs 0 with GnP). Most common grade ≥3 TEAEs with elraglusib/GnP (vs GnP) were neutropenia 52.3% (vs 30.8%) and anemia 25.2% (vs 29.5%). No differences in sepsis/febrile neutropenia rates were between arms. RAS , TP53 and CDKN2A co-mutations were associated with worse OS in the elraglusib/GnP arm only (p<0.05). Elevation in pre-dose cytokines including CXCL2 correlated with improved OS in the elraglusib/GnP arm. Additionally, increased CD8+ T cells, granzyme B, and NK cells and reduced MDSCs were observed in elraglusib-treated tumors. Conclusions: A significant benefit for 1-yr OS and mOS and a favorable trend for ORR were observed with the addition of elraglusib to GnP. The mOS was lower in the GnP arm vs historical studies, likely due to early deaths in the first 2 months, but aligns with mOS estimates in the real-world analysis with broad heterogeneous population. Our study included 19.7% pts with albumin <3.0 g/dL and >25% with CA 19.9 levels > 8,000 U/mL. Immune correlates support elraglusib’s immune-modulatory role. Final efficacy data cut-off in Dec 2025 and correlative studies will be presented. Clinical trial information: NCT03678883 . Outcome Elraglusib/GnPN=155 GnPN=78 Primary endpoint: mOS (mo)HR=0.62; log-rank p=0.01 10.1 7.2 Events, n (%) 115 (74.2) 70 (89.7) Primary endpoint: 1-yr OS (%) 44.1 22.3 18-month OS (%) 20.5 4.4 24-month OS (%) 13.2 0 mPFS (mo)HR=0.9; p=NS 5.6 5.1 Events, n (%) 136 (87.7) 75 (96.2) ORR, n (%) 44 (28.4) 17 (21.8)

64 Background: The incidence of eoCRC (diagnosed at age <50) is increasing. We have previously shown higher rates of severe anxiety and depression in this group compared to adults diagnosed at age ≥50 (average-onset CRC, aoCRC). We assessed the impact of ePROM collection coupled with a CC-based supportive care intervention on symptom burden in patients with eoCRC. Methods: The Enhanced, EHR-facilitated Cancer Symptom Control (E2C2) trial was a cluster-randomized, pragmatic trial conducted at Mayo Clinic Rochester and within the Mayo Clinic Health System (in Minnesota and Wisconsin) between 2019 and 2023. Enrolled patients serially reported the severity of six SPPADE symptoms (Sleep deficit, Pain, Physical function impairment, Anxiety, Depression, and Energy deficit/fatigue) on 11-point numerical rating scales. Symptom scores were interpreted as none to mild (0-3), moderate (4-6), or severe (7-10). Those with moderate symptoms were offered symptom management education and self-management materials, while those with severe symptoms were offered the option to work with a symptom care manager. In this post hoc analysis we examined the effects of the intervention on change in symptom scores among those with eoCRC, and using the Kaplan-Meier method, the median time to improvement to a mild/moderate level in those with a severe symptom, comparing eoCRC with aoCRC. Results: Among 4,422 patients with CRC, 887 had eoCRC. Forty-six percent of patients were female ( p =0.61), and a greater proportion of eoCRC patients were of a non-white race (11.6% vs 4.7%), lived in an urban setting (65.6% vs 50.5%), had a Bachelor’s degree or higher (36.8% vs 24.4%), were employed (78.5% vs 36.7%), on a non-government insurance plan (83.4% vs 35.3%), single (19.7% vs 11.2%) or married (74.2% vs 67.9%), and had metastatic disease (54.8% vs 46.1%, p <0.0001 for all). Compared to a pre-intervention baseline, the mean change in symptom scores for eoCRC patients following the intervention demonstrated improvements in anxiety (-0.238), depression (-0.134), and fatigue (-0.146, p <0.05 for all). Time to symptom improvement from severe to mild/moderate was longer for anxiety and depression in eoCRC patients compared to aoCRC patients (Table 1). Conclusions: Collection of ePROMs coupled with a CC-based intervention led to improvements in anxiety, depression, and fatigue among eoCRC patients, although time to symptom improvement was longer among eoCRC patients compared to aoCRC patients. Time to improvement of severe symptom (months), median (95% CI). eoCRC aoCRC p -value Sleep 4.2 (3.1-5.8) 3.8 (2.7-5.4) 0.4 Pain 4.1 (3.0-7.5) 3.2 (2.3-5.0) 0.5 Physical function impairment 3.1 (1.9-6.3) 2.8 (2.2-4.2) 0.5 Anxiety 4.3 (3.4-9.1) 2.6 (2.0-3.5) 0.009 Depression 4.3 (2.6-7.5) 2.6 (2.1-3.5) 0.04 Fatigue 4.3 (3.7-9.5) 3.4 (2.7-4.2) 0.06

476 Background: Outcomes remain poor for patients with advanced/metastatic CCA treated with first-line gemcitabine-cisplatin +/- anti-PD(L)1. Lirafugratinib is the first highly selective, irreversible FGFR2 inhibitor designed to target oncogenic FGFR2 driver alterations and resistance mutations. ReFocus (NCT04526106) is an open-label, multicenter phase 1/2 study in patients with advanced/metastatic CCA and other solid tumors with FGFRok2 alterations. Methods: Pivotal cohort of patients (n=116) with advanced/metastatic CCA harboring FGFR2 f/r previously treated with ≥1 systemic therapy and FGFR i-naive were treated with oral lirafugratinib 70 mg once daily until disease progression or unacceptable toxicity. The primary endpoint was confirmed ORR per RECIST v1.1 by independent review committee (IRC). Key secondary endpoint was duration of response (DOR); other secondary endpoints: disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and quality of life per EORTC QLC-C30. Results: As of 27SEP2024, the primary efficacy analysis of IRC-assessed data (n=114) and the secondary analysis of investigator-assessed data (n=116) set was done. The primary efficacy analysis excluded 2 patients as not available. Median age 57 years with 61.4% female. IRC-assessed ORR was 47%, and median DOR was 11.8 months (mos) (95% CI, 7.5-13.0), where 76.2% of responses lasted >6 mos. Median PFS was 11.3 mos (95% CI, 9.2, 14.8), with 12-month rate of 49.2%. Median OS was 22.8 mos (95% CI, 17.3-27.2), with 12-month rate of 74.6%. DCR was 96.5%. Common grade ≥3 on-target, off-tumor treatment-related adverse events (TRAEs) included palmar-plantar erythrodysesthesia (32.8%) and stomatitis (12.1%). TRAEs led to dose reductions of 75.9%, dose interruption of 82.8%, and treatment discontinuation of 4.3%. QoL was maintained. Conclusions: Lirafugratinib demonstrated clinically meaningful anti-tumor activity (ORR, DOR, and PFS), manageable and tolerable safety in CCA FGFR2 f/r patients. Clinical trial information: NCT04526106 . Best Overall Response, n (%) IRC c Investigator d Complete Response Partial Response Stable Disease Progression Disease Not Evaluable 3 (2.6)50 (43.9)57 (50.0)3 (2.6)1 (0.9) 061 (52.6)51 (44.0)3 (2.6)1 (0.9) ORR a , n (%)95% CI 53 (46.5)37.1, 56.1 61 (52.6)43.1, 61.9 DCR b , n (%)95% CI 110 (96.5)91.3, 99.0 112 (96.6)91.4, 99.1 a ORR defined as proportion achieving confirmed response of complete response or partial response per RECIST v1.1. b DCR defined as proportion with confirmed response of complete response, partial response, or stable disease per RECIST v1.1. c Primary Efficacy Analysis Set. d Secondary Efficacy Analysis Set. Percentages based on number of patients in the analysis set for each treatment arm. Exact Clopper-Pearson used for 95% CI. IRC and investigator assessments are based on different populations and cannot compare directly.

451 Background: In first-line E/GEJ/G adenocarcinoma, anti-PD-1 + chemotherapy improves outcomes, yet many patients do not respond. Beyond PD-L1 CPS, tumor-intrinsic biomarkers of primary resistance remain limited. We applied a validated IFN-γ–linked T cell-inflamed (Tinfl) framework to define exclusionary programs and nominate targets. Methods: Bulk RNAseq was analyzed from TCGA ESCA/STAD adenocarcinoma (n=79, discovery) and a de novo Mayo cohort of pretreatment samples (n=74, validation) with harmonized survival and response data. Tinfl scores (160-gene signature) defined quartiles (Q1 cold, Q4 hot). Cold versus hot tumors were compared by edgeR + limma-voom to identify differentially expressed genes (DEGs) (Bioconductor v3.20). Pathway and upstream-regulator/causal-network analyses used Ingenuity Pathway Analysis seeded by top DEGs (|log2FC|>1.5, p<0.05). Survival was assessed by Cox proportional hazards models (two-sided α=0.05) and KM log-rank testing (α=0.05). A 14-gene Tinfl-weighted cold signature produced a per-sample composite score. Results: In the Mayo cohort, median age was 62 years; 72% were stage IV at diagnosis; 24% were HER2-positive and 3% MSI-H; primary sites were GEJ/esophagus/gastric 50%/34%/16%; PD-L1 CPS <1/1–5/6–49/≥50 occurred in 18%/46%/27%/4%; patients received a mean of 2.4 lines of therapy. Across discovery and validation cohorts, Tinfl-cold tumors showed significantly higher expression of developmental and lineage transcription factors (HOXC12, HOXC13, ZIC1, DLX3, EVX1), an oncofetal post-transcriptional hub (IGF2BP1), cancer-testis and piRNA components (MAGEA4, TDRD12, THEG), and neuronal or transport genes (GABRQ, KCNF1, LDLRAD1, SLC6A10P) (logFC >2, p<0.05). Pathway analysis highlighted chromatin and lineage regulators (KAT6A, SIRT1, LEF1), TGF-β signaling (TGFBR2), and repressors of innate DNA/IFN sensing (TREX1, IRF2BP2) (Z-score >2, p<0.05). The 14-gene Tinfl-weighted cold signature was higher in cold versus hot tumors (p<0.05) and showed a directional association with inferior overall survival in the Mayo validation cohort. Among patients who received first-line anti-PD-1–containing regimens, several signature members and the composite score were higher in non-responders (p<0.05). Conclusions: Using a discovery–validation design, we define tumor-intrinsic expression pathways that characterize Tinfl-cold E/GEJ/G adenocarcinoma. We also derive a concise 14-gene Tinfl-weighted cold signature that is enriched in non-responders and associated with inferior overall survival. Targetable nodes such as IGF2BP1 and MAGEA4, together with chromatin and Wnt/TGF-β regulators, support rational combinations with PD-1 blockade. Planned validation in a third cohort, single-cell confirmation of tumor-cell expression, and in vivo cytokine profiling in knockdown models will refine mechanisms and nominate clinical candidates.

Abstract Background Candidemia can occur as a consequence of gastrointestinal (GI) injury. The mortality of candidemia is high, ranging 30-60%, even with treatment with antifungal agents. In this retrospective matched case-control study, we aimed to elucidate the medical and surgical risk factors of developing candidemia in patients who received emergency surgery for GI ischemia and/or perforation, and compare clinical outcomes in these patients with or without candidemia. Methods All patients ≥ 18 years of age who had emergency GI surgery at Mayo Clinic Rochester, MN, for the indication of GI ischemia and/or perforation between 01/01/2018 to 07/31/2024 were included. Cases were defined as patients who developed candidemia during index admission and had no alternative sources of candidemia. Controls and cases were matched 4:1 on age (± 5 years), Charlson Comorbidity Index (± 3), and year of surgery (± 2 years). The relationships between risk factors of interest and case/control were assessed using conditional logistic regression. Results Among medical risk factors, any shock requiring vasopressor (OR = 3.44, 95% CI 1.00, 11.97) or respiratory failure (OR = 8.20, 95% CI 1.04, 64.53) during hospitalization were associated with increased risk of candidemia. Among surgical risk factors, perforation in the upper GI tract was strongly associated with development of candidemia (OR = 16.99, 95% CI 2.11, 136.95) and perforation in the lower GI tract were less likely to lead to candidemia (OR = 0.06, 95% CI 0.01, 0.44). The patients who had diffuse intraabdominal contamination were more likely to develop candidemia compared to those who had no contamination or contained contamination (OR = 3.87, 95% CI 1.33, 11.25). The patients with candidemia showed signal towards higher in-hospital and 30-day mortality, and had significantly longer stay in the hospital. Conclusion Candidemia was more frequently identified in patients with shock, respiratory failure, upper GI perforation, and intra-abdominal contamination, and contributed to significant morbidity and mortality. Further analysis will include building a multivariate logistic regression model to implement prospective trial for early initiation of antifungal therapy for high-risk population. Disclosures All Authors: No reported disclosures

Abstract Background Outpatient parenteral antimicrobial therapy (OPAT) is effective and cost-efficient, but 12%–63% of patients experience adverse events, requiring close monitoring. Therapeutic drug monitoring (TDM) is routinely used for vancomycin and aminoglycosides but is underutilized for beta-lactams (BLs) due to limited access, logistical barriers, and clinician inexperience. This study evaluated its use and clinical impact within a high-volume OPAT program. Methods This retrospective, single-center cohort included adult patients (≥18 years) enrolled in an OPAT program who received cefepime (CEF), piperacillin/tazobactam (TZP), or meropenem (MEN) and underwent BL TDM between April 2023 and April 2025. BL TDM was not protocolized within the OPAT program; however, institutional guidance supported its use in carefully selected patients. We aimed to describe TDM indications, lab trends, microbiological profiles, and the impact of TDM on treatment. Results During the study period, 25 OPAT patients underwent BL TDM. TDM was performed in patients receiving CEF (64%), TZP (20%), and MEN (16%). The most common indication for TDM was suspected beta-lactam toxicity (32%) (Figure 1). Post-TDM therapy adjustments were made in 52% (n = 13), including changes in dosing frequency (38.5%) and dosage strength (30.8%). Additional changes included infusion strategy modification or agent substitution (15.4% each). Subtherapeutic levels were the most common reason for adjustment (46.2%), followed by adverse effects, supratherapeutic levels, and changes in renal function (23.1% each). Skin, soft tissue, and musculoskeletal infections were most common (Figure 2). Positive cultures were present in 80%, with Pseudomonas spp most frequently isolated. Therapy was completed in 17 patients; 7 discontinued early, and 1 had treatment ongoing. Reasons for therapy discontinuation are detailed in Table 1. Conclusion BL TDM is contributing to a paradigm shift in OPAT practice by improving both efficacy and safety. While inpatient TDM typically targets efficacy, safety concerns more commonly motivate TDM in the OPAT setting. Although this review involved a small cohort, our experience adds to the growing body of evidence supporting BL TDM as a tool to enhance patient outcomes in the OPAT setting. Disclosures All Authors: No reported disclosures

Abstract Background According to consensus guidelines, area under the concentration–time curve (AUC) is recommended for vancomycin dosing rather than trough-based monitoring, but transition to AUC-based dosing requires substantial staff education and resource allocation. We sought to evaluate the level of congruency between vancomycin total daily doses (TDD) determined using a trough concentration goal of 10-15 mcg/mL compared with an online Bayesian calculator targeting an AUC of 400-600 mg·h/L.Patient DemographicsInitial Dose Results Methods We performed a retrospective, multicenter cohort study of vancomycin therapeutic drug monitoring (TDM) in non–critically ill adults hospitalized from March 1, 2017-December 31, 2021. Patients were included if they received intravenous vancomycin for ≥72 hours with a documented trough target of 10 to 15 mg/L, had ≥1 serum vancomycin trough concentration assessed at steady state, and received ≥2 doses of vancomycin after serum assessment with or without dose adjustment. Using an online vancomycin calculator with Bayesian modeling, the study team input patients’ trough-based dosing data to retrospectively estimate the initial vancomycin AUC exposure achieved and the initial and post-trough TDD recommended for an AUC target of 400 to 600 mg⸱h/L. The initial and post-trough vancomycin total daily dose (TDD) derived by the online calculator were compared with the actual doses used for each patient when a trough concentration of 10 to 15 mg/L was targeted.Comparison of Trough-Based and AUC-Based Dosing of Vancomycin AUC indicates area under the concentration–time curve; TDD, total daily dose. Dashed line indicates where the 2 methods are equal; shading indicates where the 2 methods are within 20% of each other Results In total, 89 patients were included in the study. The actual vancomycin TDD with trough monitoring (target, 10-15 mg/L) was within 20% of the recommended AUC-based TDD for 62 patients (70%) with initial dosing and for 74 (83%) after the initial trough concentration. Nephrotoxicity was rarely observed (2%) and the median duration of vancomycin was 4 days. Conclusion Given the frequency of dosing similarity between 400-600 mg·h/L AUC and 10-15 mg/L trough-based dosing, vancomycin trough-based monitoring to a goal of 10-15 mg/L is an option warranting further exploration. Disclosures All Authors: No reported disclosures

Abstract Background In 2019, the US performed 290,000 breast reconstructions with an estimated infection rate of 3-35%. Tissue expander infections detract from desired aesthetic effects, delay adjuvant treatments, increase morbidity and mortality, and have high recurrence rates (20-40%). Little is known about risk factors for recurrent tissue expander infections, particularly the impacts of different treatment modalities. Methods We conducted a single-center retrospective cohort study of adult women post-mastectomy who developed microbiologically-proven tissue expander infection between the period of 2017 – 2024. Outcomes including 12-month infection recurrence and risk factors for recurrence were compared between surgical versus nonoperative groups, as well as between three surgical strategies (i.e., one-stage, two-stage, explantation). Unadjusted and adjusted logistic regression models were used to assess the associations between the treatment modalities and the outcomes. Univariate models assessed the relationship between the covariates of interest and infection recurrence. Results 107 patients were included, with the majority treated with combination of antibiotics and surgical therapy (Table 1). There was no significant difference in outcomes when the operative versus antibiotics alone cohorts were compared (Table 2). The odds of infection recurrence and rehospitalization in patients who underwent two-staged exchange or explantation were significantly lower when compared with the one-staged group (Table 3). Univariate modeling found severity and radiation therapy to be numerically more common in the group experiencing recurrence, with a trend towards statistical significance (Table 4). Conclusion Our study demonstrates reduced risk of recurrent tissue expander infection with two-staged exchange or explantation, compared to one-staged exchange. Though limited by small sample size, the strengths of our study include our presentation of the real-world variability of these syndromes and their management, adjustment for infection severity and other potential confounders; and the focus on microbiologically-defined infections. Disclosures All Authors: No reported disclosures