Citations

e13036 Background: In January 2023, the FDA approved elacestrant for ESR1-mutated, ER+/HER2- MBC based on a companion diagnostic cell free (cf)DNA test (Guardant Health). In this study, we analyze the trends of liquid biopsy utilization at Mayo Clinic (MC) over a 3 year period to understand the impact of this drug approval on testing patterns and identify emergent alterations in patients (pts) with MBC. Methods: We extracted clinically performed Guardant 360 and Guardant 360 CDx ordered at MC sites in Rochester (MN), Florida (FL), Arizona (AZ), and across 9 additional Mayo Clinic Health System (MCHS) sites. Pts with MBC were identified using the EMR and analyzing visit diagnosis codes and staging information. Shifts in testing patterns were analyzed over a 3 year period from January 1, 2021 - December 31, 2023. Data was collected on the number of tests, serial testing, frequency of pathogenic mutations, and emergent mutations in ESR1 and PIK3CA. Chi-square test was used to compare the categorical values. Results: Between 2021-2023, 2,741 pts with MBC were seen across all sites. A total of 408 cfDNA tests were performed in 370 unique patients with MBC. Most pts (90%) had 1 test performed. The proportion of pts with MBC tested was 85/1350 (6.3%) in 2021, 77/1495 (5.2%) in 2022, and 208/1558 (13.4%) in 2023. The increased proportion of pts tested in 2023 was statistically significant compared to prior years (p<0.0001), while no difference was observed between 2021 and 2022 (p 0.19). Testing patterns varied by site, with FL ordering the highest number of tests, followed by MN and AZ. Of the 34 providers practicing during the entire period seeing more than 10 MBC pts, the number of providers ordering Guardant testing increased from 15/34 (2021) and 14/34 (2022) to 20/34 (2023), though not statistically significant (p 0.15). Of the 41% with EMR-documented staging available, testing was highest in the ER+/HER2- (81.3%) subtype, followed by TNBC (13.6%) and then HER2+ (5.2%). The most commonly identified mutations identified in the first testing were PIK3CA (41.1%), TP53 (40.5%), ESR1 (30.5%), and ATM (13.2%). D538G (8.0%), Y537N (4.4%), and Y537S (3.5%) were frequent emergent mutations seen in ESR1. Conclusions: We observed an increase in cfDNA testing at the start of 2023 which aligns with the FDA approval of elacestrant. We observed variation by site and individual providers that warrants further exploration to improve cfDNA testing in MBC pts at Mayo Clinic.

e23554 Background: Follicular dendritic cell sarcoma (FDCS) is a low-grade neoplasm arising from follicular dendritic cells. Its diagnosis is challenging due to its extreme rarity, and the optimal management remains unknown. Methods: We conducted a retrospective study of FDCS patients (pts) seen at Mayo Clinic, MN since 2018. Time to event analyses were done from the time of diagnosis. Results: Ten pts with FDCS were identified (Table). The median age was 60 years (range, 38-76) and 5 were males. Abdominal pain was the most common presenting symptom (30%) followed by constitutional symptoms, shortness of breath, and vision change. In 3 pts, the diagnosis was incidental. The 2 most common primary locations were abdomen/pelvis (50%) and mediastinum (30%). Six pts (60%) presented with advanced disease and 3 (30%) had Castleman’s disease. Most (60%) had advanced disease. Six pts had Epstein-Barr virus in situ hybridization and all tested negative. Seven pts had next generation sequencing and 5 (83%) had genetic alterations detected with CDKN2A/B alterations being most frequent (3 pts, all with advanced disease). The median follow up was 4.3 years (range, 0.2-13.3). In the 4 patients with localized disease, 3 underwent complete surgical excision resulting in complete remissions (CRs). The one who received radiation had a partial remission (PR). The median time to progression after 1st line treatment was 4 months (all with advanced disease). All 3 pts who died had advanced disease and 2 had CDKN2A/B alterations. Conclusions: In FDCS, localized diseases managed by surgical excision with or without radiation can achieve long term remissions. Advanced diseases generally do not respond to multimodality therapy including immunotherapy but can have disease stabilization with variable survival. CDKN2A/B mutations were common and potentially associated with a worse outcome. Better understanding of the impact of the FDCS mutational landscape on prognosis may provide novel approaches to therapy. [Table: see text]

e23310 Background: Chimeric antigen receptor T-cell therapy (CAR T) is FDA-approved in pts with triple-class exposed (TCE) relapsed/refractory (RR) MM after four or more prior lines of therapy (LOTs). Real-world access to CAR T remains challenging due to manufacturing capacity, financial barriers, and pt fitness. Pts with certain pre-existing comorbidities (e.g., central nervous system disease, heart disease, secondary malignancies) are commonly excluded from clinical trials, including those investigating CAR T. The objective of this study was to identify the factors associated with the use of CAR T in pts with TCE RRMM to better understand the unmet need in this population. Methods: We conducted an observational cohort study using Medicare fee-for-service data; each pt in the CAR T intention-to-treat (ITT) population between 2021 and 2023 was matched to three non-CAR T pts, without replacement. Pts were eligible if they had an initial MM diagnosis, were continuously enrolled, were TCE, and did not receive treatment in a clinical trial. The index date was the ITT date. Baseline characteristics included age, sex, race/ethnicity, census region, three comorbidity indexes (Charlson, Elixhauser, CMS hierarchical condition categories [HCCs]), a claims-based frailty index (CFI), and dual enrollment in Medicare and Medicaid (as a proxy to social economic status [SES]). Logistic regression was used to derive odds ratios (ORs) and 95% confidence intervals (CIs) comparing the characteristics of CAR T vs non-CAR T pts. Results: Seventy-three ITT CAR T pts (nine underwent apheresis but did not receive CAR T) were matched to 219 non-CAR T pts by LOT and index year. Matched pts were treated with varied standard regimens (daratumumab-containing: 63%). Median prior LOTs were similar in the two cohorts (8; range 2–13). Median time from MM diagnosis to index date was 44.6 and 51.9 months for CAR T and non-CAR T pts, respectively. Compared with non-CAR T pts, pts in the CAR T population were younger (aged < 75 years: 59% CAR T vs 36% non-CAR T), less frail (mean CFI: 0.18 vs 0.20) and had higher SES (without dual enrollment in Medicare and Medicaid: 96% vs 81%), but were similar in terms of sex, region, and race/ethnicity. Variation in individual comorbidity prevalence was observed between CAR T and non-CAR T pts. In a multivariable regression analysis, factors strongly associated with lower odds of CAR T use included age ≥75 years (OR 0.29; 95% CI 0.16–0.53), comorbidities (lung/other severe cancers [OR 0.39; 95% CI 0.20–0.74] and chronic obstructive pulmonary disease [OR 0.32; 95% CI 0.10–0.99] defined by HCCs), and SES (OR 0.09; 95% CI 0.02–0.37). Conclusions: Older age, certain comorbidities, and lower SES are associated with lower odds of receiving CAR T in real-world pts with TCE RRMM, demonstrating an unmet need for more accessible and effective treatment options with acceptable safety profiles for these pts.

e23309 Background: BCMA-directed T-cell–engaging therapies have been introduced into clinical practice for the treatment of TCE RRMM. While efficacious, such treatments are associated with safety considerations such as cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and serious infections. These treatments also vary in reported efficacy, administration processes, and hospitalization requirements. The aim of this study is to quantify patient preferences and tradeoffs regarding these attributes. Methods: A discrete choice experiment (DCE) was designed to elicit preference weights corresponding to seven attributes related to efficacy (objective response rate [ORR], overall survival [OS]), safety (all-grade CRS, all-grade ICANS, serious infections) and treatment procedures (treatment administration, hospitalization requirements). Attribute levels were based on plausible ranges of potential values. Patients in the United States (US) with a physician-confirmed diagnosis of TCE RRMM were recruited. Pre-test interviews with patients were conducted and the final survey deployed online in 2023. A random-parameters logit model was used to estimate preference weights. Conditional relative importance (CRI) was calculated to rank the relative importance of each attribute. The minimum acceptable benefit (MAB) and maximum acceptable risk (MAR) were calculated to estimate the tradeoffs between efficacy and safety attributes. Results: The sample included 200 respondents (mean [standard deviation] age: 61 [6.4] years; 43% female; 46% White; 10% African American). A total of 197 participants reported having responded to prior treatment, of whom 195 had relapsed or become refractory. In the DCE, a 24-month increase in OS was found to be the most important attribute, with a CRI of 32.0%. Next most important were avoiding a 60% risk of serious infection (CRI 17.3%), avoiding 14-day hospitalization requirements (CRI 15.0%), and a 38% increase in ORR (CRI 13.7%). A treatment that could be started immediately and administered weekly or up to every 4 weeks was preferred over a CAR T-like procedure with a waiting period. Fewer initial hospitalization days was significantly preferred over more hospitalization days. The MABs for OS when the risk of serious infection was increased from 20% to 60%, CRS from 40% to 95%, and ICANS from 3% to 20% were 24.2, 17.1, and 18.0 months, respectively. When OS was increased from 12 to 36 months, the estimated MARs for serious infections, CRS, and ICANS were > 60%, > 95%, and > 20%, respectively. Conclusions: This study highlights US patient preferences regarding treatment attributes for TCE RRMM. Treatment benefits and risks and the mutual tradeoffs considered by patients should be evaluated when developing and selecting therapeutic approaches.

PURPOSE ASCO/College of American Pathologists guidelines recommend reporting estrogen receptor (ER) and progesterone receptor (PgR) as positive with (1%-100%) staining. Statistically standardized quantitated positivity could indicate differential associations of positivity with breast cancer outcomes. METHODS MA.27 (ClinicalTrials.gov identifier: NCT00066573 ) was a phase III adjuvant trial of exemestane versus anastrozole in postmenopausal women with early-stage breast cancer. Immunochemistry ER and PgR HSCORE and % positivity (%+) were centrally assessed by machine image quantitation and statistically standardized to mean 0 and standard deviation (SD) 1 after Box-Cox variance stabilization transformations of square for ER; for PgR, (1) natural logarithm (0.1 added to 0 HSCOREs and 0%+) and (2) square root. Our primary end point was MA.27 distant disease-free survival (DDFS) at a median 4.1-year follow-up, and secondary end point was event-free survival (EFS). Univariate survival with cut points at SDs about a mean of 0 (≤–1; (–1, 0]; (0, 1]; >1) was described with Kaplan-Meier plots and examined with Wilcoxon (Peto-Prentice) test statistic. Adjusted Cox multivariable regressions had two-sided Wald tests and nominal significance P < .05. RESULTS Of 7,576 women accrued, 3,048 women's tumors had machine-quantitated image analysis results: 2,900 (95%) for ER, 2,726 (89%) for PgR, and 2,582 (85% of 3,048) with both ER and PgR. Higher statistically standardized ER and PgR HSCORE and %+ were associated with better univariate DDFS and EFS ( P < .001). In multivariable assessments, ER HSCORE and %+ were not significantly associated ( P = .52-.88) with DDFS in models with PgR, whereas higher PgR HSCORE and %+ were significantly associated with better DDFS ( P = .001) in models with ER. CONCLUSION Adjunctive statistical standardization differentiated quantitated levels of ER and PgR. Patients with higher ER- and PgR-standardized units had superior DDFS compared with those with HSCOREs and %+ ≤–1.

ImportanceCorticosteroid injections (CSIs) are an important tool for pain relief in many musculoskeletal conditions, but the longitudinal effects of these treatments on bone health and fracture risk are unknown.ObjectiveTo determine whether cumulative doses of corticosteroid injections are associated with higher risk of subsequent osteoporotic and nonosteoporotic fractures.Design, Setting, and ParticipantsThis cohort study included adult patients receiving any CSI from May 1, 2018, through July 1, 2022. Eligible patients resided in Olmsted County, Minnesota, and were empaneled to receive primary care within the Mayo Clinic. Cox proportional hazards regression models were used to evaluate risk of fracture based on cumulative injected corticosteroid dose.ExposureReceipt of any CSI during the study period.Main Outcomes and MeasuresThe primary outcome was risk of fracture by total triamcinolone equivalents received. Secondary outcomes consisted of risks of fracture based on triamcinolone equivalents received in subgroups of patients not at high risk for fracture and patients with osteoporosis.ResultsA total of 7197 patients were included in the study (mean [SD] age, 64.4 [14.6] years; 4435 [61.6%] women; 183 [2.5%] Black and 6667 [92.6%] White), and 346 (4.8%) had a new fracture during the study period. Of these fractures, 149 (43.1%) were considered osteoporotic. In the adjusted Cox proportional hazards regression model, there was no association of higher fracture risk based on cumulative CSI dose (adjusted hazard ratio [HR], 1.04 [95% CI, 0.96-1.11]). There was also no associated higher risk of fracture in the non–high-risk (adjusted HR, 1.11 [95% CI, 0.98-1.26]) or osteoporosis (adjusted HR, 1.01 [95% CI, 0.90-1.11]) subgroups. Age, Charleson Comorbidity Index, and previous fracture were the only factors that were associated with higher fracture risk.Conclusions and RelevanceIn this cohort study of cumulative injected corticosteroid dose and risk of subsequent fracture, no association was observed, including in patients with a preexisting diagnosis of osteoporosis. Treatment of painful conditions with CSI should not be withheld or delayed owing to concern about fracture risk.

567 Background: We proposed adjunctive statistical standardization of quantitated ER and PgR to improve inter-laboratory comparability of biomarker results and therapeutic management of breast cancer. Methods: We utilized CCTG MA.27 (NCT00066573), an adjuvant phase III trial of exemestane versus anastrozole in postmenopausal women with ER+ and/or PgR+ tumours. IHC ER and PgR HSCORE and % positivity (%+) were centrally assessed by machine image quantitation, and each statistically standardized to mean of 0, standard deviation of 1 following Box-Cox variance stabilization transformations of square for ER; for PgR, 1.) natural logarithm (0.1 added to 0 HSCOREs and 0 %+), 2.) square root. The primary endpoint was STEEP distant disease-free survival (DDFS) at the longest trial follow-up of median 4.1 years; a secondary endpoint was event-free survival (EFS). Survival was described with Kaplan-Meier plots and tested with the univariate Wilcoxon (Peto-Prentice) test statistic. We examined cut-points at standard deviations about mean of 0 (<-1; (-1,0]; (0,1]; >1) and explored single cut-points. Cox multivariate regressions were adjusted for age, T and N stage, grade, lymphovascular invasion, treatment, and baseline patient demographics; 2-sided Wald tests had nominal significance if p<0.05. Results: Of the 7576 women accrued, 3048 women had machine-quantitated image analysis results: 2900 (95%) for ER; 2726 (89%) for PgR. Statistically standardized HSCORE and %+ units differentiated both univariate DDFS and EFS; DDFS was significantly different by ER levels (p<0.001) and PgR levels (p<0.001). In multivariable assessments, ER HSCORE and %+ were not significantly associated (p=0.52-0.88) with the DDFS primary endpoint in models with PgR, while higher PgR HSCORE and %+ had significantly better DDFS (p=.001, in all instances) in models with ER. Conclusions: DDFS was superior for patients with higher ER and PgR standardized units compared with those with HSCOREs and %+ <-1. The adjunctive statistical standardization of ER and PgR performed here is similar to that mandated for clinical practice by the World Health Organization for BMD. [Table: see text]

AbstractMyhre syndrome is an increasingly diagnosed ultrarare condition caused by recurrent germline autosomal dominant de novo variants in SMAD4. Detailed multispecialty evaluations performed at the Massachusetts General Hospital (MGH) Myhre Syndrome Clinic (2016–2023) and by collaborating specialists have facilitated deep phenotyping, genotyping and natural history analysis. Of 47 patients (four previously reported), most (81%) patients returned to MGH at least once. For patients followed for at least 5 years, symptom progression was observed in all. 55% were female and 9% were older than 18 years at diagnosis. Pathogenic variants in SMAD4 involved protein residues p.Ile500Val (49%), p.Ile500Thr (11%), p.Ile500Leu (2%), and p.Arg496Cys (38%). Individuals with the SMAD4 variant p.Arg496Cys were less likely to have hearing loss, growth restriction, and aortic hypoplasia than the other variant groups. Those with the p.Ile500Thr variant had moderate/severe aortic hypoplasia in three patients (60%), however, the small number (n = 5) prevented statistical comparison with the other variants. Two deaths reported in this cohort involved complex cardiovascular disease and airway stenosis, respectively. We provide a foundation for ongoing natural history studies and emphasize the need for evidence‐based guidelines in anticipation of disease‐specific therapies.

Background Patient admissions at a U.S. tertiary care hospital occur via the emergency department (ED), or transfer center. We aim to compare the clinical outcomes of patients admitted from the ED to admissions coordinated by the transfer center. Methods Admissions to Mayo Clinic Hospital, Rochester, MN, between July 2019 to June 2021 were identified in this retrospective study and categorized into two cohorts—transfer center and ED. The two cohorts were then matched for age, sex, admitting service, and Charlson Comorbidity Index. Univariate and multivariate analyses were performed to compare hospital length of stay (LOS), mortality, 30-day mortality, and 30-day readmissions between the two cohorts. Results 73,685 admissions were identified, of which 24,262 (33%) were transfer center admissions. In the matched cohorts (n = 19,093, each), in-hospital mortality (2.4% versus 1.9%), 30-day mortality (5.4% versus 3.9%), 30-day readmission (12.7% versus 7.2%), and LOS (6.4 days versus 5.1 days) were significantly higher (P < 0.001) among the admissions coordinated by transfer center. A higher palliative care consultation rate (9.4% versus 6.2%, P < 0.001), and a lower proportion of home discharges home (76.2% versus 82.5%, P < 0.001) among transfer center admissions was observed. Similar findings were noted in multivariate analysis, even when adjusting for LOS. Conclusions Transfer center admissions had higher in-hospital mortality, LOS, 30-day mortality, and 30-day readmission compared to ED admissions. This study also highlights new considerations for palliative care consultation before transfer acceptance, especially to avoid futile transfers. Additional studies analyzing factors behind the outcomes of transfer center admissions are required.