Haddad, Tufia C.

ImportanceThere was a shift in patient volume from in-person to video telemedicine visits during the COVID-19 pandemic.ObjectiveTo determine the concordance of provisional diagnoses established at a video telemedicine visit with diagnoses established at an in-person visit for patients presenting with a new clinical problem.Design, Setting, and ParticipantsThis is a diagnostic study of patients who underwent a video telemedicine consultation followed by an in-person outpatient visit for the same clinical problem in the same specialty within a 90-day window. The provisional diagnosis made during the video telemedicine visit was compared with the reference standard diagnosis by 2 blinded, independent medical reviewers. A multivariate logistic regression model was used to determine factors significantly related to diagnostic concordance. The study was conducted at a large academic integrated multispecialty health care institution (Mayo Clinic locations in Rochester, Minnesota; Scottsdale and Phoenix, Arizona; and Jacksonville, Florida; and Mayo Clinic Health System locations in Iowa, Wisconsin, and Minnesota) between March 24 and June 24, 2020. Participants included Mayo Clinic patients residing in the US without age restriction. Data analysis was performed from December 2020 to June 2021.ExposuresNew clinical problem assessed via video telemedicine visit to home using Zoom Care Anyplace integrated into Epic.Main Outcomes and MeasuresConcordance of provisional diagnoses established over video telemedicine visits compared against a reference standard diagnosis.ResultsThere were 2393 participants in the analysis. The median (IQR) age of patients was 53 (37-64) years; 1381 (57.7%) identified as female, and 1012 (42.3%) identified as male. Overall, the provisional diagnosis established over video telemedicine visit was concordant with the in-person reference standard diagnosis in 2080 of 2393 cases (86.9%; 95% CI, 85.6%-88.3%). Diagnostic concordance by International Statistical Classification of Diseases and Related Health Problems, Tenth Revision chapter ranged from 64.7% (95% CI, 42.0%-87.4%) for diseases of the ear and mastoid process to 96.8% (95% CI, 94.7%-98.8%) for neoplasms. Diagnostic concordance by medical specialty ranged from 77.3% (95% CI, 64.9%-89.7%) for otorhinolaryngology to 96.0% (92.1%-99.8%) for psychiatry. Specialty care was found to be significantly more likely than primary care to result in video telemedicine diagnoses concordant with a subsequent in-person visit (odds ratio, 1.69; 95% CI, 1.24-2.30; P < .001).Conclusions and RelevanceThis diagnostic study of video telemedicine visits yielded a high degree of diagnostic concordance compared with in-person visits for most new clinical concerns. Some specific clinical circumstances over video telemedicine were associated with a lower diagnostic concordance, and these patients may benefit from timely in-person follow-up.

The promise of highly personalized oncology care using artificial intelligence (AI) technologies has been forecasted since the emergence of the field. Cumulative advances across the science are bringing this promise to realization, including refinement of machine learning– and deep learning algorithms; expansion in the depth and variety of databases, including multiomics; and the decreased cost of massively parallelized computational power. Examples of successful clinical applications of AI can be found throughout the cancer continuum and in multidisciplinary practice, with computer vision–assisted image analysis in particular having several U.S. Food and Drug Administration–approved uses. Techniques with emerging clinical utility include whole blood multicancer detection from deep sequencing, virtual biopsies, natural language processing to infer health trajectories from medical notes, and advanced clinical decision support systems that combine genomics and clinomics. Substantial issues have delayed broad adoption, with data transparency and interpretability suffering from AI’s “black box” mechanism, and intrinsic bias against underrepresented persons limiting the reproducibility of AI models and perpetuating health care disparities. Midfuture projections of AI maturation involve increasing a model’s complexity by using multimodal data elements to better approximate an organic system. Far-future positing includes living databases that accumulate all aspects of a person’s health into discrete data elements; this will fuel highly convoluted modeling that can tailor treatment selection, dose determination, surveillance modality and schedule, and more. The field of AI has had a historical dichotomy between its proponents and detractors. The successful development of recent applications, and continued investment in prospective validation that defines their impact on multilevel outcomes, has established a momentum of accelerated progress.

1512 Background: In response to the COVID-19 pandemic, many cancer practices adopted telehealth, including telephone and video appointments. Following a period of initial expansion that began in March 2020, sustained telehealth integration has emerged across the Mayo Clinic Cancer Practice (MCCP) in 2021. The primary objective of this study was to identify factors associated with utilization of telehealth appointments. Methods: A cross-sectional, multi-site, retrospective analysis was conducted across MCCP – a multisite, multiregional cancer practice with tertiary referral campuses in Minnesota, Florida, and Arizona, as well as rural, community-based hospitals and clinics throughout the Upper Midwest. Multivariable models were used to examine the association of patient- and provider-level variables with telehealth utilization. Results: Outpatient appointments conducted in July – August 2019 (n = 32,932) were compared with those from 2020 (n = 33,662) and 2021 (n = 35,486). The rate of telehealth appointment utilization increased from <0.01% in 2019 to 11.0% in 2020 and 14.0% in 2021. The strongest provider-level predictor of telehealth utilization was female physician provider type (OR 1.06, 95% CI 1.01 to 1.11; P = 0.0297), a trend consistently observed across career stages, practice locations and settings in 2020 and 2021. Additionally, while the rate of telehealth utilization was not significantly different at referral and community-based campuses in 2020, providers at referral campuses were significantly more likely to utilize telehealth than community-based campuses in 2021 (OR 1.1, 95% CI 1.01 to 1.12; P = 0.0289). Regarding patient-level factors, rural residence (defined by Rural-Urban Commuting Area codes), which accounted for 44.2% of the patient population, was significantly associated with lower telehealth utilization as compared to patients with urban residences, particularly for video appointments (OR 1.04, 95% CI 1.02 to 1.07; P < 0.0001). Notably, the disparity in telehealth utilization between rural and urban populations was found to be less pronounced in 2021 as compared to 2020. Conclusions: Multivariable analysis across a multi-site, multi-regional cancer practice identified several factors associated with increased telehealth utilization. These included female physician provider type, referral-based campuses, and patients residing in urban settings. A detailed understanding of the factors that influence telehealth utilization – a method of care delivery which represents a “new normal” across many cancer practices – will be essential to enable continued equitable access to high-quality, high-impact, patient-centered cancer care.

555 Background: Women with early-stage breast cancer (BCa) are living longer, and survivorship issues including second primary cancers (SPCs) are therefore increasingly important. This study seeks to determine the risk of SPCs, including contralateral breast cancer (CBCa), in women with early-stage invasive lobular carcinoma (ILC). Methods: The study population consisted of women with BCa diagnosis between 2000-2018 within the NCI Surveillance, Epidemiology, and End Results (SEER v 3.2.9) registry and between 2000-2021 in the Mayo Clinic Cancer Registry. In the SEER registry, the standardized incidence ratios (SIR) for SPCs were estimated for adult women with histologically confirmed early stage (I-III) ILC compared to the development of any primary cancer in the general population. For reference, SIRs for SPCs for a similar patient population with invasive ductal carcinoma (IDC) of the breast were also estimated. For comparison of CBCa between ILC and IDC, follow up records from the Mayo Clinic Cancer Registry were evaluated among adult women who underwent lumpectomy or unilateral mastectomy for early stage ILC or IDC. A multivariable Cox proportional hazards regression was performed to compare the risk of CBCa between ILC and IDC while adjusting for the age at diagnosis, race/ethnicity and estrogen receptor status of the primary tumor. Results: An increased incidence (p<0.05) of any SPCs and second BCa was noted for both ILC and IDC compared to the expected rate of primary cancer in the general population (Table). Interestingly, women with ILC were observed to have a significantly increased incidence of subsequent gastric cancer which was not seen for women with IDC. An SIR >1.5 was noted for subsequent risk of sarcoma, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) for both ILC and IDC (Table). In the Mayo Clinic Cancer Registry of 2,218 women with ILC and 14,629 women with IDC meeting the inclusion criteria, the 5-year risk of CBCa was 2.6% and 1.5% (log rank statistic p-value =0.001) for ILC and IDC respectively. A significantly increased risk of CBCa was noted in women with ILC (Hazard Ratio 1.82, 95% CI 1.34-2.47, p<0.001) compared to women with IDC in the multivariable analysis. Conclusions: Women with ILC may have an increased risk of SPC and second BCa compared to the risk of any primary cancer in the general population. The increased incidence of gastric cancer and the higher risk of CBCa in ILC survivors compared to women with IDC is intriguing and needs to be investigated further including evaluation of the role of germline genetic factors. [Table: see text]

Abstract Purpose Cyclin dependent kinase 4/6 inhibitors (CDK4/6is), in combination with endocrine therapy (ET), are standard either in the first (1L) or second line (2L) setting for the treatment of hormone receptor (HR) positive, HER2-negative metastatic breast cancer (MBC). However, the optimal sequencing of treatments after progression on CDK4/6i remains unknown. We performed a single institution analysis to identify treatments and outcomes after progression on a CDK4/6i. Methods We identified patients with HR-positive, HER2-negative MBC prescribed a CDK4/6i in the 1L or 2L settings from December 2014-February 2018 at Mayo Clinic in Rochester, Minnesota. Outcomes were collected through September 30, 2020. Results Palbociclib, in combination with letrozole or fulvestrant, was the most prescribed CDK4/6i. The 1L and 2L CDK4/6i cohorts exhibited comparable overall survival (OS), but progression free survival (PFS) was longer in the 1L than the 2L cohort [28.2 months (95% CI 19.6–34.9) vs 19.8 months (95% CI 15.7–29.6)]. The most common post-CDK4/6i treatments were PI3K/mTOR inhibitors (PI3K/mTORi), single agent ET, or chemotherapy. PFS in the 1L CDK4/6i cohort following PI3K/mTORi was 8.5 months (95% CI 5.5 months – NE), single-agent ET was 6.0 months (95% CI 3.3–14.0 months), and chemotherapy PFS was 5.4 months (95% CI 3.3 months- NE). Conclusions Following progression on a CDK 4/6i, mPFS was short, with similar PFS times comparing chemotherapy and ET, with slightly longer PFS for targeted strategies (PI3K/mTOR). These results highlight a major need to better understand the mechanisms of CDK4/6i resistance and identify new therapeutic strategies for these patients.

Abstract Introduction: Hepatopulmonary syndrome (HPS) is characterized by hypoxemia, portal hypertension, and intrapulmonary shunting and manifests as dyspnea. The portal hypertension may be a result of cirrhosis or non-cirrhotic causes such as nodular regenerative hyperplasia of the liver that is associated with drug therapy. Progressive hypoxemia often occurs despite stable liver function. Ado-trastuzumab emtansine (T-DM1; KADCYLA) is an antibody-drug conjugate comprised of a humanized monoclonal antibody trastuzumab covalently linked to the cytotoxic agent maytansine. T-DM1 is prescribed in the postneoadjuvant setting in persons with residual invasive HER2-positive (HER2+) breast cancer (BC) as well as in persons with metastatic HER2+ BC who were previously treated with trastuzumab and a taxane. Liver toxicities including an asymptomatic, transient increase in transaminases and nodular regenerative hyperplasia that results in portal hypertension have been described; however, HPS secondary to noncirrhotic portal hypertension occurring with long-term exposure to T-DM1 has not been reported. We have identified patients (pts) with this infrequent, yet serious complication, and we aim to better characterize their clinical course to guide earlier detection and hopefully prevent irreversible hypoxic respiratory failure. Methods: Institutional search tools were utilized to identify pts at Mayo Clinic with HER2+ BC treated with T-DM1 in either the postneoadjuvant or metastatic setting. Electronic health records were manually reviewed for HPS criteria including 1) hypoxemia 2) portal hypertension and 3) intrapulmonary shunt/vasodilation confirmed by contrast echocardiogram or macroaggregated albumin lung perfusion scan. For pts meeting criteria for HPS, imaging was independently reviewed by a hepatologist to determine whether there was preexisting liver disease or if changes occurred after initiation of T-DM1. Results: We identified 259 pts with HER2+ BC treated with T-DM1 in the postneoadjuvant (n=70) or metastatic setting (n=185). Four pts met criteria for HPS (1.5%) while receiving T-DM1 for metastatic disease (Table 1; listed in chronological order of onset of HPS). Median age was 43 (range 35 - 53 years), median prior lines of treatment was 1.5 (range 0 - 7), and the median number of cycles of T-DM1 prior to discontinuation was 68.5 (range 51 - 90). All pts had evidence of left atrial enlargement on echocardiogram, and evidence of portal hypertension as determined by the presence of varices, and splenomegaly. Three pts had documented telangiectasias as well as Grade 1-2 elevations in serum transaminases and bilirubin. Elevations in hemoglobin were noted in 2 pts during treatment with T-DM1. All pts had a confirmed intrapulmonary shunt via contrast echocardiogram and a lung perfusion scan. Three pts discontinued T-DM1 after diagnosis of HPS and experienced some clinical improvement in hypoxia. One pt died two months after stopping T-DM1 due to progression of BC. Conclusion: HPS may occur in the setting of prolonged exposure to T-DM1 and can be associated with severe hypoxic respiratory failure. Further data are required to characterize the spectrum of liver injury that occurs with long-term use of T-DM1 to provide further guidance to clinicians as regards monitoring for these adverse effects. Patients who developed hepatopulmonary syndrome while on T-DM1Age, yrsSites of metastases# lines of prior txCycles of T-DM1Presenting sign or symptomsNon-contrast ECHO findingsSupplemental oxygenTransaminitis; hyperbilirubinemiaEvidence of portal hypertensionTelangiectasiasHgb prior to T-DM1Hgb end of txLung perfusion studyContrast ECHOPt 153LN, bone090DOE, hypoxemia, clubbingleft atrial enlargement (62 mg/m2)YesNovarices, splenomegalyNot documented12.9 g/dL10.7 g/dL13.5%Yes, small shuntPt 235LN, bone, liver751DOEleft atrial enlargement (54 mg/m2)YesGrade 1; Grade 2varices, splenomegaly; thrombocytopeniaYes, face and handsn/a11.9 g/dL24%Yes, large shuntPt 338LN, bone251Hyperbilirubinemiaborderline left atrial enlargementYesGrade 1; Grade 2varices, splenomegalyYes, trunk, extremities, face11.7 g/dL16.2 g/dL17.8%Yes, moderate shuntPt 448LN, liver186DOEleft atrial enlargement (49 mg/m2)NoGrade 1; Grade 2varices, splenomegalyYes, trunk12.5 g/dL16.1 g/dL7.9%Yes, large shunt Citation Format: Ally Higgins, Adham K Alkurashi, Patrick S Kamath, Vivek N Iyer, Ciara O'Sullivan, Tufia C Haddad. Hepatopulmonary syndrome with long term use of ado-trastuzumab emtansine (T-DM1) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-18-03.

Abstract Background: Cyclin dependent 4/6 kinase inhibitors (CDK4/6i) and endocrine therapy (ET) have improved progression-free survival (PFS) and overall survival in HR+ MBC, but progression of disease ultimately occurs. Apart from HR+ status, there are no clinically available biomarkers that enable oncologists to determine prognosis and predict response to CDK4/6i. An emerging biomarker is serum thymidine kinase 1 (TK1), a secreted marker of proliferation that is prognostic in pts with HR+ HER2- MBC. High levels of TKa are associated with inferior PFS, whereas pts with low TKa levels pretreatment, or TKa levels that decrease on ET and a CDK4/6i, have superior PFS. Notably, TKa levels rebound ≥ 5 days off Pb, with resumption of cell cycling. PROMISE (NCT0281902) is a prospective study that enrolled women with HR+ MBC starting Pb + letrozole (L) in the 1st line [FL] or Pb + fulvestrant in the 2nd line [SL] setting. The trial includes a comprehensive “omic” assessment of blood, tumor, urine and the fecal microbiome to identify novel genomic variants and pathways associated with an early decline in TKa (measured after 2 months or end of cycle [C]2) and PFS. Here, we report the association between i) pre-treatment TKa (pre-TKa) levels and PFS (i.e. from registration to the 1st disease event) and ii) TKa levels at the end of C2 (C2-TKa) and PFS-2 (i.e. from the start of C3 to the 1st disease event).Methods: TKa testing was performed using the DiviTum assay (Biovica). TKa+ disease was defined as ≥ 200 Du/L and TKa- disease as below limit of detection to 200 Du/L. Log-rank test and univariate Cox modeling were used to assess the association between pre-TKa levels and PFS and between end of C2-TKa levels and PFS-2. The database was locked on June 28, 2021. Results: Of 68 pts enrolled, 4 were ineligible and pre-TKa data was unavailable for 4. Of the remaining 60 pts (45 FL, 15 SL), the percentage of pts with pre-TKa+ disease was 33.3% in FL (15/45, 95% CI: 20.0-49.0%), and 46.7% (7/15, 95% CI: 21.4-71.9%) in the SL. The median follow-up time for pts on study was 24 months (range: 2-42 months). There were 22 disease events (13 in FL, 9 in SL). In the FL setting, PFS was significantly shorter for preTKa+ pts compared to preTKa- pts (HR: 4.15, 95% CI:1.35-12.74; p=0.007), but not for SL pts (HR: 1.11, 95% CI: 0.30-4.18, p=0.875). End of C2 TKa data was obtained for pts while on Pb (n=5), or after stopping Pb as follows: 1-4 days (n=9), 5-8 days (n=28) and 9-36 days (n=11). PFS-2 was not associated with C2-TKa in the FL (p=0.834) or SL (p=0.454) settings. An analysis of TKa levels by metastatic site will be presented at the meeting.Conclusions: A secreted biomarker of proliferation (TK1) obtained prior to initiating CDK4/6i and ET for the treatment of HR+ MBC is associated with PFS in pts receiving 1st line Pb + L, but not in those receiving 2nd line Pb + fulvestrant. While the end of C2 TKa levels were not associated with PFS, the interpretability of these data are limited, given treatment delays (0-36 days) prior to starting C3 that may result in TKa rebound. Future studies evaluating the predictive nature of TKa and Pb response should focus on earlier timepoints while on drug. Citation Format: Ciara C O'Sullivan, Jun He, Jason Sinnwell, Vera J Suman, Krishna R Kalari, Peter T Vedell, Ann M Moyer, Xiaojia Tang, Kevin J Thompson, Abe Eyman Casey, Alvaro Moreno-Aspitia, Donald W Northfelt, Minetta C Liu, Tufia C Haddad, Saranya Chumsri, Brendan McMenomy, Prema Peethambaram, Kathryn J Ruddy, Karthik V Giridhar, Roberto A Leon-Ferre, Mattias Bergqvist, Adrian Nordmark, Richard M Weinshilboum, Liewei Wang, Matthew P Goetz. Serum thymidine kinase 1 activity (TKa) levels and progression-free survival (PFS) in patients (pts) with hormone receptor positive (HR+) HER2-negative metastatic breast cancer (MBC) on palbociclib (Pb) and endocrine therapy (ET) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-13-22.

Abstract Background: As the development and use of oral anticancer agents increases, it is critical to understand patient adherence to both standard and investigational agents. The open label, phase 3 multicenter PALLAS trial investigates whether adding 2 years of the CDK4/6 inhibitor palbociclib (P) to adjuvant endocrine therapy (ET) improves invasive disease-free survival (iDFS) over adjuvant ET alone in patients (pts) with HR- positive, HR2-negative, stage II-III breast cancer. Pts were randomly assigned to either Palbociclib (125 mg/day, 3 weeks on, 1 week off, in a 28-day cycle) plus ongoing provider/patient-choice adjuvant ET (P+ET) versus ET alone. We examined patient-reported adherence to ET +/- P during the first two years of study treatment. Methods: Adherence outcomes were measured in English-speaking pts in the U.S., UK, Ireland and Australia, Spanish-speaking pts in Spain and Mexico, and German-speaking pts in Germany and Austria. Adherence measures included drug diaries completed at each cycle, pill counts (for P only) collected at each study visit, and the Morisky Medication Adherence Scale-4 item and the McHorney Adherence Estimator questionnaires completed at cycles 2, 3, 6, 12, 18, and 24 (22 months). Mean adherence for each cycle was defined as the average proportion of prescribed pills taken (via drug diary) across all patients who initiated that cycle. Persistence was defined as the duration of drug initiation to treatment cessation (via drug diary). Generalized estimating equations were used to model the “most adherent” pts on the Morisky (score = 5 vs score &lt;5) and “low risk” for adherence problems on the McHorney (score=0 vs score &gt;0) to compare the average difference between arms over time for ET, adjusting for baseline demographic and clinical variables. Results: 81% (N=4688) of PALLAS pts were included in this analysis. Median persistence to ET was 23.6 months in P + ET (n=2169), 23.7 months in ET alone (2136) and 20.4 months for P (n=2194). The number of pts who initiated each cycle for ET declined over time and was similar between arms; the decline was more marked for P (Table 1). Mean adherence range as measured by drug diary was 98.2-99.3% for ET in P+ET and 98.0 - 99.4% in ET alone; and for P, ranged from 93.4 - 98.8%. The adherence and persistence results were nearly identical whether measured by drug diary or pill count for P. The observed percent “most adherent” for P measured by the Morisky scale ranged from 71.9% - 79.6% and the percent “low risk” for adherence problems measured by the McHorney scale, 64.0% - 73.4%. The percent of pts “most adherent” and “low risk” for adherence problems to ET was higher, on average over time, in the P+ET group compared to ET alone (75% vs 68%, p&lt;0.01; 75% vs 72%, p=.05, respectively). Conclusions: Self-reported mean adherence for both P + ET and ET alone was strikingly high for pts who remained on therapy; persistence was also high with ET during the 2-year treatment period. Current analyses suggest that nonadherence to either P or ET was likely not a major contributor to the iDFS results seen in the overall PALLAS trial. These results illustrate the importance of measuring and monitoring patient adherence to oral study agents. Support: AFT, Pfizer; ClinicalTrials.gov (NCT02513394) and EudraCT (2014-005181-30). https://acknowledgments.alliancefound.org Table 1.Adherence and persistence in PALLAS over the 24 month treatment periodPalbocicilb + ETETPalbociclibETETTreatment cycleMean Adherence (SD)N*Mean Adherence (SD)NMean Adherence (SD)N193.4 (13.8)229098.7 (6.1)230999.0 (5.2)2343294.7 (13.3)218198.8 (6.4)220398.4 (7.1)2206397.4 (10.1)211298.7 (7.3)214298.8 (6.3)2168497.6 (10.2)203598.6 (7.8)211099.0 (5.7)2154597.6 (11.1)197598.3 (7.9)209398.1 (8.3)2148698.1 (8.7)189998.7 (6.6)203798.5 (8.2)2116798.1 (9.3)185599.0 (6.3)201298.6 (7.3)2102898.0 (9.1)181098.2 (8.2)199798.1 (8.2)2092998.4 (7.4)173399.0 (6.4)196298.8 (6.8)20511098.3 (8.6)171499.2 (4.9)194699.0 (5.5)20381198.3 (8.0)169198.5 (7.3)193798.2 (8.2)20311298.7 (6.2)161299.1 (5.3)191098.7 (7.5)19861398.5 (7.7)159698.9 (6.4)189398.8 (7.1)19691497.9 (9.3)157698.4 (7.3)188298.0 (9.1)19611598.5 (6.9)151499.2 (4.6)185499.0 (6.0)19281698.2 (8.7)148699.1 (4.6)183599.1 (5.7)19131798.1 (9.8)147998.3 (7.8)182698.5 (6.4)19031898.7 (6.8)141699.3 (4.1)176899.2 (5.3)18601998.7 (7.3)140899.3 (3.8)175699.4 (3.1)18482098.4 (8.9)139798.9 (5.3)174298.7 (5.8)18382198.5 (7.5)130199.0 (6.1)167698.8 (7.1)17842297.8 (9.7)124698.8 (6.2)164799.2 (5.7)17692398.1 (8.8)118098.2 (8.5)161998.4 (8.0)17552498.8 (7.2)108699.0 (6.3)146898.9 (7.1)16192598.8 (6.7)99699.2 (5.2)143298.8 (7.1)15892697.9 (11.2)84599.1 (5.7)140998.6 (8.8)1578ET=Endocrine therapy * Number of pts who initiated the treatment cycle. Citation Format: Eileen Shinn, David Zahrieh, Angela DeMichele, Nick Zdenkowski, Julie Lemieux, Jun Mao, Vesna Bjelic-Radisic, Michelle Naughton, Georg Pfeiler, Karen Gelmon, Ingrid Mayer, Daniel Egle, Gabriele Zoppoli, Tiffany Traina, Miguel Martin Jiménez, Silvia Antolin Novoa, Tufia Haddad, Arlene Chan, Alistair Edward Ring, Antonio Wolff, Jose JuanPonce Lorenzo, Dhanusha Sabanathan, Hal Burstein, Zbigniew Ireneusz Nowecki, Gunda Pristauz-Telsnigg, Adam Brufsky, Meritxell Bellet-Ezquerra, Theodoros Foukakis, Yelena Novik, Gabor Rubovszky, Karoline Muehlbacher, Otto Metzger, Theodora Goulioti, Ernest Law, Ann Partridge, Lisa Carey, Alex Zoroufy, Dominik Hlauschek, Christian Fesl, Erica Mayer, Michael Gnant. Adherence with adjuvant endocrine therapy with or without Palbociclib in the PALLAS trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-12-01.

Abstract Background: Hormone receptor-positive (HR+) breast cancer (BC) accounts for ~60-70% of all BC cases. CDK4/6i combined with endocrine therapy (ET) is the standard of care for first- and second-line therapy of patients with HR+ metastatic breast cancer (MBC) based on substantial improvements in progression free survival (PFS) and overall survival compared to ET alone. Unfortunately, most patients (pts) develop resistance to CDK4/6i. The mechanisms underlying CDK4/6i resistance have not been fully elucidated. Robust in vivo CDK4/6i resistant animal models from pts with de novo and acquired CDK 4/6i resistance are lacking. Patient-derived xenografts (PDXs) are important preclinical tools in oncology to advance our understanding of cancer biology and to evaluate drug response phenotypes. Unfortunately, the establishment of sustainable PDXs from pts with HR+ BC is much more difficult than from HR-negative BC. In order to obtain clinically relevant models that can be utilized to better understand mechanisms of primary and acquired resistance to ET and CDK4/6i, we report the development of PDXs from a prospective study in which percutaneous biopsies were obtained from women receiving palbociclib for the treatment of HR+ advanced or MBC (PROMISE; NCT03281902). Methods: PROMISE (Prospective Study to Evaluate the Role of Tumor Sequencing in Women Receiving Palbociclib for Advanced Hormone Receptor (HR)-Positive Breast Cancer) is a prospective trial which enrolled pts with HR+, HER2-negative MBC who planned to start treatment with palbociclib and letrozole (1st line [FL]) or palbociclib and fulvestrant (2nd line [SL]). For pts enrolled at Mayo Clinic Rochester (MCR), serial tumor biopsies were obtained prior to the start of treatment and at disease progression to establish PDXs. Because baseline take rate was low, we amended the protocol to attempt PDX generation after the 2nd cycle (C2) of therapy. Tissues were received within an hour of excision and were orthotopically implanted in the mammary fat pad of 6~8-week-old nonobese diabetic (NOD)/SCID/IL-2g-receptor null (NSG) mice. Tumor growth was defined as tumor volume ≥ 50 mm3. Tumor take rate was defined as percent of patients with development of at least one stably transplantable (passed at least for two generations) xenograft that was pathologically confirmed as BC. Results: Of the 50 pts enrolled at MCR, 37 were FL pts (2 ineligible) and 13 were SL pts (1 ineligible). Fresh tumor samples obtained pre-treatment from 43 eligible pts (32 FL), after C2 from 17 eligible pts (13 FL), and at disease progression from 10 eligible pts (5 FL) were implanted. Tumor growth was seen in at least one mouse from a pre-treatment specimen in 1 (3.1%) FL pt (confirmed BC) and 4 (36.4%) SL pts (2 confirmed BC); from end of C2 specimens in 2 (15.4%) FL pts and 2 (50%) SL pts (1 confirmed BC); and at progression in 1 (20%) FL pt and 2 (40%) SL pts (1 confirmed BC). The take rate from pre-treatment samples among FL pts was 1/32 (3.1%; 95% CI: 0.08-16.2%). Take rates in other groups are pending histological review. Discussion: In pts receiving palbociclib for HR+ MBC, the take rate using a pre-treatment percutaneous biopsy was low (3.1%) in the FL setting. However, higher growth rates were seen in the SL setting. The observation of higher growth rates at the end of C2 and at progression may relate to the activation of G1/S that occurs with withdrawal of palbociclib, and should be further studied. PDX remains a valuable tool for the evaluation of tumor biology and the development of new therapeutics, especially for those models established from pts with palbociclib and ET resistance. Proteogenomic and sequencing studies are ongoing to fully characterize these PDXs. Citation Format: Jia Yu, Vera J. Suman, Jun He, Jason P. Sinnwell, Ann M. Moyer, Bo Qin, Yayun Gu, Huan Zhang, Jodi M. Carter, Krishna R. Kalari, Brendan P. McMenomy, Minetta C. Liu, Tufia C. Haddad, Kathryn J. Ruddy, Fergus J. Couch, Alvaro Moreno-Aspitia, Donald W. Northfelt, Richard Weinshilboum, Ciara O'Sullivan, Matthew P. Goetz, Liewei Wang. Patient-derived xenografts (PDXs) generated from hormone receptor-positive breast cancer (BC) before and after cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) treatment: Initial findings from the PROMISE study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-01-07.

Abstract Background: Cyclin-dependent 4/6 kinase inhibitors (CDK4/6i) and endocrine therapy (ET) have improved progression-free survival (PFS) and overall survival in hormone-receptor-positive (HR+) metastatic breast cancer (MBC), but endocrine resistance is a major challenge. PROMISE [NCT0281902; n=63] is a multicenter study that enrolled women with HR+ HER2- MBC commencing palbociclib (Pb) with letrozole (1st line [1L]) or fulvestrant (2nd line [2L]), and was designed to perform a comprehensive “omic” assessment of prospectively collected biospecimens (pre-treatment (M1), at 2 months (M2), and at disease progression). The goal is to identify novel genomic variants and pathways associated with resistance to CDK4/6i and ET and PFS outcomes. Here we report the association between the proteomic, metabolomics, and lipidomics data generated from pre-Pb and 2-month serum samples and PFS. Methods: Untargeted mass spectrometry data was generated from Metabolon, assaying 1308 metabolites and 831 lipids. Additionally, 1436 proteins were assayed on the Olink platform. Cox proportional hazard models were used to evaluate the univariate hazard ratio (HR) for all features with respect to PFS. The analyses were performed on samples from 45 patients (N=33 1Lwith 9 progression events and 12 2L with 8 progression events), obtained from M1 and M2 timepoints on Pb + ET. Enrichment analysis p-values are calculated using Fisher’s exact test. Results: Proteomics: In the M1 timepoint, 93 and 43 proteins were associated with PFS in the 1L and 2L settings, respectively; inflammation genes were enriched among the 1L setting (p= 0.034); 33 proteins presented HRs ranging between 0.026 and 0.56. The FABP9 protein (HR of 1.98, 95% CI 1.02-3.83) was associated with worse PFS. Conversely, inflammation genes were not observed to be enriched in 2L. In the M2 timepoint, we observed 60 and 21 proteins significantly associated with PFS, but no biological function was enriched in 1L and 2L. Metabolites: In the M1 timepoint, metabolism of the sulfur-containing amino acids (methionine, cysteine, SAM and taurine) were enriched in the 1L setting (p= 0.035, HR range 0.15-0.33); and the branched-chain amino acids (leucine, isoleucine, and valine) were significantly associated with PFS in the 2L setting (p= 0.028, HR range 0.013-0.33). At the M2 timepoint, the amino acids were no longer enriched, but fatty acid metabolism was significantly enriched for both 1L and 2L (p= 0.048 and 0.067, respectively). Pathways involving lipids, amino acids, and xenobiotics were enriched in metabolites related to PFS (p &lt;0.05) for both treatment lines at M1 and M2. Lipidomics: In the M1 timepoint, 10 and 19 lipids were associated with PFS for 1L and 2L, respectively. The most notable lipid associated with worse PFS in the 1L was an 18 carbon phosphatidylinositol, PI(18:1/18:2), (HR 7.34 (CI 1.27-42.50); 8 triglycerides were associated with improved PFS (HR range 0.39 and 0.55). In 2L, the 19 lipids associated with PFS included 12 phosphatidylcholines (enrichment p = 5.6X10-8). In the M2 timepoint, 15 and 8 lipids were significantly associated with PFS for 1L and 2L. An enrichment of phosphatidylinositols was observed in 1L (p= 1.2X10-5); none were observed in the 2L.Future Directions: Networks are being constructed using the proximity scores of the proteins, lipids, and metabolites associated with PFS in M1 and M2 for 1L and 2L. Network similarities and analyses will be conducted.Conclusion: Distinct multi-omic changes identified in serum samples obtained from PROMISE participants M1 and M2 on Pb correlate with disease progression in both 1L and 2L settings. Additionally, validation studies will determine the significance of these findings. Citation Format: Krishna R. Kalari, Kevin J. Thompson, Jason Sinnwell, Xiaojia Tang, Vera J. Suman, Jun He, Seul Kee Byeon, Akhilesh Pandey, Abe Eyman Casey, Peter T. Vedell, Ann M. Moyer, Alvaro Moreno-Aspitia, Donald W. Northfelt, Minetta C. Liu, Tufia C. Haddad, Saranya Chumsri, Prema Peethambaram, Kathryn J. Ruddy, Karthik V. Giridhar, Roberto A. Leon-Ferre, Richard M. Weinshilboum, Liewei Wang, Ciara C. O’ Sullivan, Matthew P. Goetz. Multiomics data reveal novel biomarkers for CDK4/6 resistance [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-01-03.