Associations of Multiparametric Breast MRI Features, Tumor-Infiltrating Lymphocytes, and Immune Gene Signature Scores Following a Single Dose of Trastuzumab in HER2-Positive Early-Stage Breast Cancer

Dynamic biomarkers that permit the real-time monitoring of the tumor microenvironment response to therapy are an unmet need in breast cancer. Breast magnetic resonance imaging (MRI) has demonstrated value as a predictor of pathologic complete response and may reflect immune cell changes in the tumor microenvironment. The purpose of this pilot study was to investigate the value of breast MRI features as early markers of treatment-induced immune response. Fourteen patients with early HER2+ breast cancer were enrolled in a window-of-opportunity study where a single dose of trastuzumab was administered and both tissue and MRIs were obtained at the pre- and post-treatment stages. Functional diffusion-weighted and dynamic contrast-enhanced MRI tumor measures were compared with tumor-infiltrating lymphocytes (TILs) and RNA immune signature scores. Both the pre-treatment apparent diffusion coefficient (ADC) and the change in peak percent enhancement (DPE) were associated with increased tumor-infiltrating lymphocytes with trastuzumab therapy (r = -0.67 and -0.69, p < 0.01 and p < 0.01, respectively). Low pre-treatment ADC and a greater decrease in PE in response to treatment were also associated with immune-activated tumor microenvironments as defined by RNA immune signatures. Breast MRI features hold promise as biomarkers of early immune response to treatment in HER2+ breast cancer.

Abstract 2719: Tumor-associated macrophage reprogramming by novel nano-in-cryogel biomaterials for breast cancer immunotherapy

Tumor-associated macrophages (TAMs) represent more than 50% of the immune cells in breast tumors, even in immune dysregulated, ‘cold’ tumors. TAMs that express an M2-like phenotype promote tumor growth and create an immunosuppressive tumor microenvironment (TME). High levels of M2-like TAMs correlate with a poor prognosis. However, macrophages display phenotypic plasticity and can be repolarized from one phenotype to another through signaling molecules, such as cytokines. Macrophages that express an M1-like phenotype are inflammatory and can induce anti-tumor immunity. Administration of pro-inflammatory cytokines reprogram M2 TAMs toward an M1-like phenotype that can reduce tumor growth and stimulate an inflammatory response within the TME. However, systemic delivery of these inflammatory cytokines generates toxic, dose-limiting off target effects. This work seeks to develop a localized delivery approach that enables TAM polarization toward M1 programs while abrogating systemic toxicities. We have developed an injectable alginate cryogel (hydrogel fabricated at -20oC) to act as localized delivery depot for inflammatory cytokines and macrophage-specific chemokines to repolarize TAMs. To delay the release of our chemoattractant relative to our repolarizing cytokines, we are developing a second generation cryogel, loaded with free chemokines and poly(lactic-co-glycolic acid) (PLGA) nanoparticles encapsulated with cytokines to delay their release. With our first generation cryogel (without nanoparticles), we used qRT-PCR, flow cytometry, Luminex panels, and single cell RNAseq to characterize the impact of treatment. For in vitro studies, bone marrow derived macrophages were extracted from FVB mice, while TAMs and tumor explants were extracted from the spontaneous mammary tumors of PyMT mice. It was found that our cryogel significantly increased M1 markers and decreased M2 markers in all three in vitro models.Peritumoral injection of the cryogel system into FVB female mice with orthotopic mammary tumors resulted in significantly suppressed tumor growth, an increase in T cell infiltration, and an increase in the M1:M2 ratio of TAMs. This activated immune response and elevated presence of T cells suggests that localized chemokine/cytokine treatment ‘primes’ the TME, potentially making it more susceptible to immunotherapies that rely on T cells, such as immune checkpoint blockade.We have concluded that our first-generation gel demonstrates the potential of priming the TME to slow tumor growth. Characterization of our second generation, nano-in-cryogel system is currently underway. Based on mathematical modeling, we hypothesize that the nano-in-cryogel will induce a more pronounced repolarization effect by allowing the chemoattractant to induce M2 TAM migration prior to the release of the inflammatory, reprogramming cytokines from the PLGA nanoparticles.

Citation Format: Sydney Ros Henriques, Ori Z. Chalom, Evan B. Glass, Sohini Roy, Abigail E. Manning, Benjamin C. Hacker, Marjan Rafat, Laura C. Kennedy, Fiona E. Yull, Young J. Kim, Todd D. Giorgio. Tumor-associated macrophage reprogramming by novel nano-in-cryogel biomaterials for breast cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2719.

Abstract P2-23-05: Trastuzumab-Induced Tumor Microenvironment Changes in Early HER2+ Breast Cancer

Background Trastuzumab (H) is a critical component of therapy (tx) for HER2+ breast cancers (BCs) and can induce anti-tumor immune responses that as part of its mechanism of action. Pre-clinical studies have suggested that antibody-dependent cell-mediated cytotoxicity (ADCC) through NK cells is a major driver of the immune response. However, there is also evidence that macrophages and dendritic cells (DCs) can play an important role in H immune response through antibody-dependent cellular phagocytosis (ADCP). Here, we present pre- and post-tx gene expression and immunohistochemistry (IHC) data to characterize the tumor microenvironment (TME) changes in response to a single dose of H in patients (pts) with early HER2+ BC. Methods Pts with Stage I-III HER2+ BC with minimum 1 cm tumors were eligible. Pts received 8 mg/kg IV H followed by tissue collection. There was a minimum of 14 days between (btw) H and post-tx tissue collection. Pre- and post-tx tissues were assessed for tumor-infiltrating lymphocytes (TILs), immune-related gene expression, and AE1/3, CD31, CD4, CD8, CD11b, CD68, and CD56 expression through IHC. Results Thirteen pts were enrolled and evaluable. 5/13 were estrogen-receptor positive (ER+). TILs were assessed independently by two pathologists and the results averaged. Tx with H resulted in an increase in TILs in the post-tx tissue (p &lt; 0.01). Pre-tx TILs ranged from 2-80% (median 6%) and post-tx TILs ranged from 2-80% (median 20%). 6/13 pts had immune infiltration (Inf), defined as a TIL increase of greater than 1 decile btw pre- and post-tx samples. 2/6 pts with Inf were ER+. Pts with Inf had a significantly higher DC immune signature (ISS) compared to pts without Inf (p &lt; 0.01, univariate analysis). No other ISS reached significance. 6 pts had paired pre- and post-tx samples evaluated by IHC. 4/6 pts had Inf per prior definition. Pts with Inf had an increase in CD11b+ (includes macrophages and some DCs) and CD56+ cells (includes NK cells) after H tx within the tumor compartment (p &lt; 0.05). Pts with Inf had an increase in CD11b+, CD56+, and CD44+ cells in the stromal compartment (p &lt; 0.05). Conclusions Innate immune cells such as macrophages and DCs are key players in H-induced immune response in the early HER2+ BC TME. This data is consistent with prior pre-clinical findings.

Citation Format: Laura C. Kennedy, Rebeca Alvarez, Suzanne Dintzis, Vijayakrishna K. Gadi. Trastuzumab-Induced Tumor Microenvironment Changes in Early HER2+ Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-23-05.

Abstract GS5-03: Evaluation of anti-PD-1 Cemiplimab plus anti-LAG-3 REGN3767 in early-stage, high-risk HER2-negative breast cancer: Results from the neoadjuvant I-SPY 2 TRIAL

Background: I-SPY2 is a multicenter, phase 2 trial using response-adaptive randomization within biomarker subtypes defined by hormone-receptor (HR), HER2, and MammaPrint (MP) status to evaluate novel agents as neoadjuvant therapy for high-risk breast cancer. The primary endpoint is pathologic complete response (pCR). Cemiplimab is an anti-PD-1 inhibitor approved for the treatment of NSCLC and cutaneous basal and squamous cell CA. Lymphocyte activation gene 3 (LAG-3) binds MHC class II leading to inhibition of T-cell proliferation and activation and is often co-expressed with PD-1. REGN3767 is a fully humanized mAb that binds to LAG-3 and blocks inhibitory T-cell signaling. Concurrent blockade of LAG-3 with an anti-PD-1 may enhance efficacy of an anti-PD-1.

Methods: Women with tumors ≥ 2.5cm were eligible for screening. Only HER2 negative (HER2-) patients were eligible for this treatment; HR positive (HR+) patients had to be MP high risk. Treatment included Paclitaxel 80 mg/m2 IV weekly x 12 and Cemiplimab 350 mg and REGN3767 1600 mg both given q3weeks x 4, followed by doxorubicin/cyclophosphamide (AC) every 2 weeks x 4. The control arm was weekly paclitaxel x 12 followed by AC every 2-3 weeks x 4. Cemiplimab/REGN3767 was eligible to graduate in 3 of 10 pre-defined signatures: HER2-, HR-HER2-, and HR+HER2-. The statistical methods for evaluating I-SPY 2 agents has been previously described. To adapt to changing standard of care, we constructed “dynamic controls” comprising ‘best’ alternative therapies using I-SPY 2 and external data and estimated the probability of Cemiplimab/REGN3767 being superior to the dynamic control. Response predictive subtypes (Immune+ vs Immune-) were assessed using pre-treatment gene expression data and the ImPrint signature.

Results: 73 HER2- patients (40 HR+ and 33 HR-) received Cemiplimab/REGN3767 treatment. The control group included [357 patients with HER2- tumors (201 HR+ and 156 HR-) enrolled since March 2010. Cemiplimab/REGN3767 graduated in both HR-/HER2- and HR+/HER2- groups; estimated pCR rates (as of June 2022) are summarized in the table. Safety events of note for Cemiplimab/REGN3767 include hypothyroidism 30.8%, adrenal insufficiency (AI) 19.2%, hyperthyroidism 14.1%, pneumonitis 1.3%, and hepatitis 3.8%. All were G1/2 except for 6 (7.7%) G3 AI and 3 (3.8%) G3 colitis. Rash occurred in 62.8%, 9% G3 and 2 pts (2.6%) had pulmonary embolism. X% of adrenal insufficiency cases required replacement therapy. 40 patients (11 HR+ and 29 HR-) in Cemiplimab/REGN3767 were predicted Immune+; 32 (29 HR+ and 3 HR-) were predicted Immune-. In the HR+ group pCR was achieved in 10/11 (91%) patients with Immune+ subtype compared with 8/29 (28%) with Immune- subtype. Additional biomarker analyses are ongoing and will be presented at the meeting.

Conclusion: The I-SPY 2 study aims to assess the probability that investigational regimens will be successful in a phase 3 neoadjuvant trial. Dual immune blockade with a LAG-3 inhibitor and anti-PD1 therapy resulted in a high predicted pCR rate both in HR-/HER2- (60%) and HR+/HER2- (37%) disease. The novel Imprint signature identified a group of HR+ patients most likely to benefit from this active regimen.

Table 1: Estimated pCR rates

Citation Format: Claudine Isaacs, Rita Nanda, Jo Chien, Meghna S. Trivedi, Erica Stringer-Reasor, Christos Vaklavas, Judy C. Boughey, Amy Sanford, Anne Wallace, Amy S. Clark, Alexandra Thomas, Kathy S. Albain, Laura C. Kennedy, Tara B. Sanft, Kevin Kalinsky, Hyo S. Han, Nicole Williams, Mili Arora, Anthony Elias, Carla Falkson, Smita Asare, Ruixiao Lu, Maria Pitsouni, Amy Wilson, Jane Perlmutter, Hope Rugo, Richard Schwab, W. Fraser Symmans, Nola M. Hylton, Laura Van’t Veer, Douglas Yee, Angela DeMichele, Donald Berry, Laura J. Esserman, I-SPY Investigators. Evaluation of anti-PD-1 Cemiplimab plus anti-LAG-3 REGN3767 in early-stage, high-risk HER2-negative breast cancer: Results from the neoadjuvant I-SPY 2 TRIAL [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-03.

Abstract 5980: Identification of pre-treatment tumor habitats for the prediction of neoadjuvant therapy response in triple negative breast cancer

Introduction: Triple negative breast cancer (TNBC) patients exhibit varied levels of response to neoadjuvant chemotherapy (NAC), with only 27-51% of patients achieving pathological complete response (pCR). This diverse response can be attributed in-part to heterogeneity of the tumor microenvironment, affecting therapeutic delivery and efficacy. Multiparametric magnetic resonance imaging (MRI) can be used to spatially resolve intratumoral heterogeneity into distinct tumor subregions, or habitats. We investigated whether MRI-derived tumor habitats identified prior to initiation of NAC were predictive of pathological response in TNBC patients.

Methods: Women with stage II/III TNBC who received a pre-treatment (baseline) breast MRI and NAC at our institution (2012-2019) were retrospectively identified. Pathological response was determined at surgery, with pCR defined as no residual tumor within the breast or lymph nodes. Both diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI data were collected prior to initiation of NAC. The apparent diffusion coefficient (a measure of cell density) was calculated for each voxel from DW-MRI. Signal enhancement ratio, percent enhancement, and wash-out slope were calculated for each voxel from DCE-MRI, providing measures of vascularity. Hierarchical clustering of voxel data was used to identify tumor habitats, with each subregion labeled in terms of “high” or “low” vascularity and cellularity based on mean parameter values for the subregion. Tumor composition was quantified as percent tumor volume comprised by each habitat. Differences between pCR and non-pCR patients were assessed using Wilcoxon rank sum test, with p&lt;0.05 considered significant.

Results: 46 women with TNBC were retrospectively identified (median age: 48, range 31-77 yrs), of which 14 (30%) achieved pCR. No significant differences between pCR and non-pCR patients were observed in baseline tumor volume or longest diameter (p&gt;0.05). Clustering analysis yielded four tumor habitats: low-vascularity low-cellularity (LV-LC), low-vascularity high-cellularity (LV-HC), high-vascularity low-cellularity (HV-LC), and high-vascularity high-cellularity (HV-HC). Patients who achieved pCR had significantly higher fraction of the HV-HC habitat at baseline (p=0.02). No significant differences were observed for other habitats.

Discussion & Conclusion: Our findings suggest multiparametric MRI can identify physiologically-distinct tumor habitats prior to NAC, which are predictive of response. A higher fraction of HV-HC habitat was associated with pCR, potentially suggestive of increased therapeutic delivery/sensitivity. Clinical translation of this approach would enable more specific characterizations of tumor heterogeneity and prediction of response, which could aid in personalizing regimens for optimal outcomes.

Citation Format: Anum S. Kazerouni, Laura C. Kennedy, Shaveta Vinayak, Suzanne Dintzis, Habib Rahbar, Savannah C. Partridge. Identification of pre-treatment tumor habitats for the prediction of neoadjuvant therapy response in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5980.

Abstract 1981: Immune related liver toxicity and potential risk factors: A case-control study

Introduction: Immune-related hepatitis (irH) is a serious but unpredictable immune-related adverse event of checkpoint inhibitor (CPI) therapy. The impact of underlying liver pathology, including liver cirrhosis or metastasis, on the incidence of irH remains poorly understood. We hypothesized that presence of underlying liver pathology would increase the risk of irH in patients with cancer treated with CPI.

Methods: We conducted a retrospective case-control study of irH in patients with cancer receiving CPI at the University of Washington/Seattle Cancer Care Alliance between 2016 and 2020. Cases of irH were first identified through relevant ICD-10 codes, followed by systematic chart review to confirm provider-documented diagnosis and biochemical criteria for ≥ grade II immune related hepatitis. Controls were matched to cases in a 2:1 ratio based on age (± 5 years), sex, time of CPI initiation (± 1 year), and available follow-up time. Cases were excluded if there were no available controls. Conditional logistic regression was used to estimate the relationship between irH, liver metastasis at CPI initiation and history of cirrhosis, and adjusted for covariates, including ECOG performance status at CPI initiation, combination (vs single agent) CPI, history of autoimmune disease, and hepatitis B or C infection.

Results: Of the 97 cases of irH identified, 43% were women and median age was 61; 45% were undergoing treatment for skin, 22% for genitourinary, 16% for lung, 8% for head/neck cancers and 5% for GI cancers including HCC. 94% of cases had metastatic disease at CPI initiation, including 27% of cases with liver metastases. Cirrhosis was present in only 4.9% (n=5) of cases. Among cases, median doses of CPI received prior to onset of irH was 2 (IQR 1-4). Biochemical liver injury presented with transaminase elevation with median peak values of AST 152 (IQR 101-316), ALT 221 (IQR 139-327), alkaline phosphatase 142 (IQR 92-330) and total bilirubin 0.9 (IQR 0.5-1.6). History of cirrhosis was associated with lower odds of irH (adjusted OR 0.15, 95% CI 0.03-0.76). Presence of liver metastasis was associated with an increased odds of irH (OR 2.61, 95% CI 1.42-4.80), although the association between irH and liver metastasis lost significance (OR 2.0, 95% CI 0.94-4.26) when adjusted for covariates, particularly combination CPI therapy.

Conclusion: We demonstrated an independent negative association between liver cirrhosis and irH, while liver metastasis was not significantly associated with increased odds of irH after adjustment for covariates. The former might be related to misattribution, low number of cases with cirrhosis, and/or potentially due to suppressed transaminase elevation due to underlying hepatocyte exhaustion. Limitations include retrospective nature, small sample size of specific case subsets, potential selection and confounding biases; our findings are hypothesis-generating and warrant external validation.

Citation Format: Erica M. Storm, Dimitrios Makraki, Genevieve I. Lin, Laura C. Kennedy, Eshana E. Shah, Amanda I. Phipps, Iris W. Liou, David Hockenbery, Petros Grivas, Ali R. Khaki. Immune related liver toxicity and potential risk factors: A case-control study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1981.

Liquid Biopsy Assessment of Circulating Tumor Cell PD-L1 and IRF-1 Expression in Patients with Advanced Solid Tumors Receiving Immune Checkpoint Inhibitor

BACKGROUND

Reliable biomarkers that can be serially monitored to predict treatment response to immune checkpoint inhibitors (ICIs) are still an unmet need. Here, we present a multiplex immunofluorescence (IF) assay that simultaneously detects circulating tumor cells (CTCs) and assesses CTC expression of programmed death ligand-1 (PD-L1) and interferon regulatory factor 1 (IRF-1) as a candidate biomarker related to ICI use.

OBJECTIVE

To assess the potential of CTC PD-L1 and IRF-1 expression as candidate biomarkers for patients with advanced epithelial solid tumors receiving ICIs.

PATIENTS AND METHODS

We tested the IF CTC assay in a pilot study of 28 patients with advanced solid tumors who were starting ICI. Blood for CTC evaluation was obtained prior to starting ICI, after a single cycle of therapy, and at the time of radiographic assessment or treatment discontinuation.

RESULTS

At baseline, patients with 0-1 CTCs had longer progression-free survival (PFS) compared to patients with ≥ 2 CTCs (4.3 vs 1.3 months, p = 0.01). The presence of any PD-L1+ CTCs after a single dose of ICI portended shorter PFS compared to patients with no CTCs or PD-L1- CTCs (1.2 vs 4.2 months, p = 0.02); the presence of any PD-L1+ or IRF-1+ CTCs at time of imaging assessment or treatment discontinuation also was associated with shorter PFS (1.9 vs 5.5 months, p < 0.01; 1.6 vs 4.7 months, p = 0.05). CTC PD-L1 and IRF-1 expression did not correlate with tumor tissue PD-L1 or IRF-1 expression. Strong IRF-1 expression in tumor tissue was associated with durable (≥ 1 year) radiographic response (p = 0.02).

CONCLUSIONS

Based on these results, CTC PD-L1 and IRF-1 expression is of interest in identifying ICI resistance and warrants further study.

Abstract PD11-08: Associations of baseline breast MRI metrics and immune infiltration with chemotherapy response in triple negative breast cancer

Introduction: In triple-negative breast cancer (TNBC), both response to neoadjuvant chemotherapy (NAC) and the degree of pre-treatment (pre-tx) tumor immune infiltration as defined by tumor-infiltrating lymphocytes (TILs) are prognostic. Improving NAC response prediction in early TNBC would provide the opportunity to consider adjustments to the NAC regimen prior to initiating therapy. Breast magnetic resonance imaging (MRI) enables noninvasive whole-tumor measurement of microenvironment features. We investigated the value of pre-tx MRI metrics in addition to TILs for the prediction of NAC response in early TNBC patients. Methods: Women with Stage I-III TNBC who underwent pre-tx clinical breast MRI and NAC at our institution (2005-2019) were retrospectively identified. Response to NAC was noted, with pathologic complete response (pCR) defined as no residual invasive cancer present within the breast. When tissue was available, diagnostic biopsy was used to quantify pre-tx TILs as deciles from 10-100% by a breast pathologist. Patients underwent pre-tx breast MRI on either a 1.5T or 3T scanner including diffusion-weighted (DW-) and dynamic contrast-enhanced (DCE-) MRI. From DCE-MRI, tumor longest diameter (LD) and T stage (1-4), as well as contrast kinetics including percent enhancement (PE) at 2 minutes post-contrast and signal enhancement ratio (SER) were determined. Tumor peak PE and peak SER (representing the highest mean PE and SER, respectively, for 3×3 voxel subregions) and functional tumor volume (FTV, tumor volume exhibiting PE ≥ 50%) were calculated. Mean apparent diffusion coefficient (ADC) was calculated from DW-MRI. TIL levels and imaging features were compared between pCR and non-pCR groups by Wilcoxon rank sum test and performance for prediction of pCR was evaluated using areas under the curve (AUC) measures from receiver operating characteristic curve analysis. Results: 115 TNBC patients (median age: 49, range 26-79 years) were evaluated, of which 45 (39%) achieved pCR. The majority received an anthracycline-containing regimen. Pre-tx TILs (evaluated in N=60 with available biopsy specimens) ranged from 10% to 80% (median, 10%) and were significantly higher in pCR vs. non-pCR patients (p = 0.02, AUC = 0.63). Pre-tx lesion size on imaging was predictive of response (Table 1), with pCR patients having significantly lower LD (p &lt; 0.01, AUC = 0.68) and FTV (p = 0.01, AUC = 0.67). Peak PE was also associated with response, significantly lower in pCR patients (p = 0.04, AUC = 0.62), while SER and ADC were not (p &gt; 0.05). Stratifying by T stage, both peak PE (p = 0.03) and FTV (p = 0.05) were predictive of response in T1/T2 patients, while no imaging metrics reached significance in T3/T4 patients. Discussion: In a large cohort of TNBC patients undergoing NAC, measures of tumor size and immune infiltration were strongly predictive of NAC response. Preliminary results suggest that baseline peak PE and FTV are associated with NAC response, particularly in earlier stage TNBC patients. These findings support the utility of imaging and TILs assessments to predict response in TNBC and potentially guide NAC regimens for improved outcomes. Future work will extend these analyses to assess the value of changes in imaging metrics over the course of NAC to predict response. Acknowledgments: NIH P30CA015704, R01CA248192, and Roger E. Moe Fellowship, ASCO/CCF Hayden Family Foundation Young Investigator Award in Breast Cancer

Summary of imaging characteristics across TNBC cohort. Values indicate mean (standard deviation).Whole cohort. N=115T1/T2. N=80T3/T4. N=35pCR. N=45non-pCR. N=70pAUCpCR. N=39non-pCR. N=41pAUCpCR. N=6non-pCR. N=29pAUCLongest dimension (mm)34 (15)50 (27)&lt;0.010.6829 (11)31 (10)0.410.5561 (6)76 (20)0.060.75FTV (cm3)14.7 (17.0)31.2 (43.4)0.010.6710.4 (11.0)19.0 (20.2)0.050.6446.1 (24.5)52.0 (58.0)0.720.57Peak SER1.77 (0.26)1.78 (0.23)0.960.501.76 (0.26)1.79 (0.23)0.690.531.91 (0.19)1.78 (0.26)0.270.68Peak PE (%)234 (61)268 (69)0.040.62237 (61)275 (71)0.030.66247 (70)256 (63)1.000.5ADC(×10-3 mm2/s)1.19 (0.29)1.31 (0.36)0.180.581.16 (0.28)1.24 (0.30)0.390.561.40 (0.30)1.4 (0.43)0.900.48

Citation Format: Anum S Kazerouni, Laura C. Kennedy, Michael Hirano, Bonny Chau, Debosmita Biswas, Shaveta Vinayak, Matthew J. Nyflot, Habib Rahbar, Suzanne Dintzis, Savannah C. Partridge. Associations of baseline breast MRI metrics and immune infiltration with chemotherapy response in triple negative breast cancer [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 PD11-08.

New targets in endocrine-resistant hormone receptor-positive breast cancer

Endocrine-based treatments are the backbone of initial therapy for advanced hormone receptor-positive breast cancers. Developing new therapeutic strategies to address resistance to endocrine therapy is an area of active research. In this review, we discuss targeted therapies that are currently the standard of care, as well as agents that are at present under investigation as potential treatments for advanced hormone receptor-positive breast cancer.

Quantification of Human Epidermal Growth Factor Receptor 2 by Immunopeptide Enrichment and Targeted Mass Spectrometry in Formalin-Fixed Paraffin-Embedded and Frozen Breast Cancer Tissues

BACKGROUND

Conventional HER2-targeting therapies improve outcomes for patients with HER2-positive breast cancer (BC), defined as tumors showing HER2 protein overexpression by immunohistochemistry and/or ERBB2 gene amplification determined by in situ hybridization (ISH). Emerging HER2-targeting compounds show benefit in some patients with neither HER2 protein overexpression nor ERBB2 gene amplification, creating a need for new assays to select HER2-low tumors for treatment with these compounds. We evaluated the analytical performance of a targeted mass spectrometry-based assay for quantifying HER2 protein in formalin-fixed paraffin-embedded (FFPE) and frozen BC biopsies.

METHODS

We used immunoaffinity-enrichment coupled to multiple reaction monitoring-mass spectrometry (immuno-MRM-MS) to quantify HER2 protein (as peptide GLQSLPTHDPSPLQR) in 96 frozen and 119 FFPE BC biopsies. We characterized linearity, lower limit of quantification (LLOQ), and intra- and inter-day variation of the assay in frozen and FFPE tissue matrices. We determined concordance between HER2 immuno-MRM-MS and predicate immunohistochemistry and ISH assays and examined the benefit of multiplexing the assay to include proteins expressed in tumor subcompartments (e.g., stroma, adipose, lymphocytes, epithelium) to account for tissue heterogeneity.

RESULTS

HER2 immuno-MRM-MS assay linearity was ≥103, assay coefficient of variation was 7.8% (FFPE) and 5.9% (frozen) for spiked-in analyte, and 7.7% (FFPE) and 7.9% (frozen) for endogenous measurements. Immuno-MRM-MS-based HER2 measurements strongly correlated with predicate assay HER2 determinations, and concordance was improved by normalizing to glyceraldehyde-3-phosphate dehydrogenase. HER2 was quantified above the LLOQ in all tumors.

CONCLUSIONS

Immuno-MRM-MS can be used to quantify HER2 in FFPE and frozen BC biopsies, even at low HER2 expression levels.

Untangling the Multidisciplinary Care Web: Streamlining Care Through an Immune-Related Adverse Events (IRAE) Tumor Board

Immune-related adverse events (IRAEs) are becoming increasingly common as the use of immune checkpoint inhibitors expands into more tumor types and treatment settings. Although the majority of IRAEs are mild and can be managed in the outpatient setting by the medical oncologist, severe IRAEs can be life threatening and often require complex care coordination among multiple providers. These providers include a variety of non-oncology specialists who have interest and expertise in managing IRAEs. Multiple systems-based solutions have been proposed in the literature, but these need to be tailored to the needs and resources of each practice setting. In this article, we highlight the challenges of IRAE care by presenting an illustrative case from our institution. We then describe the format and structure of the IRAE Tumor Board established at the University of Washington/Seattle Cancer Care Alliance/Fred Hutchinson Cancer Research Center. Finally, we discuss how this tumor board attempts to address clinical issues related to complex IRAE presentations and provide IRAE education.

"Those Conversations in My Experience Don't Go Well": A Qualitative Study of Primary Care Provider Experiences Tapering Long-term Opioid Medications

Objective

Given the risks of long-term opioid therapy, patients may benefit from tapering these medications. There is little evidence to guide providers' approach to this process. We explored primary care providers' experiences discussing and implementing opioid tapering with patients on long-term opioid therapy.

Design

Qualitative study using six semistructured, in-person focus groups.

Subject

Primary care providers (N = 40).

Setting

Six academically affiliated primary care clinics in university, urban safety net, and Veterans Health Administration medical centers in Colorado.

Methods

Focus groups were audio-recorded, transcribed, and analyzed using a mixed inductive-deductive approach in ATLAS.ti. Emergent themes were identified through an iterative, multidisciplinary team-based process.

Results

We identified 1) strategies for identifying candidates for opioid tapering, 2) barriers to opioid tapering, and 3) facilitators of opioid tapering. Strategies for identifying candidates for opioid tapering included evidence of high-risk behavior, serious adverse events, opioid-related side effects, and patient preference. Barriers included the providers' emotional burden, inadequate resources, and a lack of trust between patient and provider. Facilitators of opioid tapering included empathizing with the patient's experience, preparing patients for opioid tapering, individualizing implementation of opioid tapering, and supportive guidelines and policies.

Conclusions

While discussing and implementing opioid tapering present significant challenges, primary care providers described key facilitators. These findings suggest a need to develop and test the effectiveness of resources to support patient-centered opioid tapering and locally developed policies to support and standardize providers' approaches to opioid prescribing.

Preexisting Autoimmune Disease: Implications for Immune Checkpoint Inhibitor Therapy in Solid Tumors

The use of immune checkpoint inhibitors (ICIs) is rapidly expanding to the treatment of many cancer types, both in the metastatic setting and as an adjuvant to other therapies. Clinical trials using ICIs have largely excluded patients with preexisting autoimmune diseases due to concerns for increased toxicity. However, emerging evidence shows that ICIs may be considered in some patients with autoimmunity. This review discusses the commonalities between clinical autoimmune diseases and ICI-induced immunotherapy-related adverse events, and summarizes the existing case series that describes patients with solid tumors who have a preexisting autoimmune disease. This review also discusses which patients with autoimmunity could be considered reasonable candidates for ICI therapy.

Elimination of metastatic melanoma using gold nanoshell-enabled photothermal therapy and adoptive T cell transfer

Ablative treatments such as photothermal therapy (PTT) are attractive anticancer strategies because they debulk accessible tumor sites while simultaneously priming antitumor immune responses. However, the immune response following thermal ablation is often insufficient to treat metastatic disease. Here we demonstrate that PTT induces the expression of proinflammatory cytokines and chemokines and promotes the maturation of dendritic cells within tumor-draining lymph nodes, thereby priming antitumor T cell responses. Unexpectedly, however, these immunomodulatory effects were not beneficial to overall antitumor immunity. We found that PTT promoted the infiltration of secondary tumor sites by CD11b⁺Ly-6G/C⁺ myeloid-derived suppressor cells, consequently failing to slow the growth of poorly immunogenic B16-F10 tumors and enhancing the growth of distant lung metastases. To exploit the beneficial effects of PTT activity against local tumors and on antitumor immunity whilst avoiding the adverse consequences, we adoptively transferred gp100-specific pmel T cells following PTT. The combination of local control by PTT and systemic antitumor immune reactivity provided by adoptively transferred T cells prevented primary tumor recurrence post-ablation, inhibited tumor growth at distant sites, and abrogated the outgrowth of lung metastases. Hence, the combination of PTT and systemic immunotherapy prevented the adverse effects of PTT on metastatic tumor growth and optimized overall tumor control.

Size-controlled synthesis of monodispersed gold nanoparticles via carbon monoxide gas reduction

An in depth analysis of gold nanoparticle (AuNP) synthesis and size tuning, utilizing carbon monoxide (CO) gas as a reducing agent, is presented for the first time. The sizes of the AuNPs are tunable from ~4 to 100 nm by altering the concentration of HAuCl4 and inlet CO gas-injection flow rate. It is also found that speciation of aqueous HAuCl4, prior to reduction, influences the size, morphology, and properties of AuNPs when reduced with CO gas. Ensemble extinction spectra and TEM images provide clear evidence that CO reduction offers a high level of monodispersity with standard deviations as low as 3%. Upon synthesis, no excess reducing agent remains in solution eliminating the need for purification. The time necessary to synthesize AuNPs, using CO, is less than 2 min.

T cells enhance gold nanoparticle delivery to tumors in vivo

Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production). Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation.

A new era for cancer treatment: gold-nanoparticle-mediated thermal therapies

Nanotechnology-based cancer treatment approaches potentially provide localized, targeted therapies that aim to enhance efficacy, reduce side effects, and improve patient quality of life. Gold-nanoparticle-mediated hyperthermia shows particular promise in animal studies, and early clinical testing is currently underway. In this article, the rapidly evolving field of gold nanoparticle thermal therapy is reviewed, highlighting recent literature and describing current challenges to clinical translation of the technology.

Relationship between juvenile obesity, dietary energy and fat intake and physical activity

OBJECTIVE

To determine the relationship of juvenile obesity to dietary fat, particularly saturated fat, and with dietary energy (controlling for activity patterns).

DESIGN

Cross-sectional, evaluation of diet and activity patterns of obese and non-obese children and adolescents.

SUBJECTS

A total of 181 children, aged 4-16 y. Subjects were divided into two groups: obese (body mass index, BMI, > 95th percentile for age and sex), 40 males and 51 females; and non-obese (BMI < 75th percentile for age and sex), 35 males and 55 females.

MEASUREMENTS

Dietary intake was analyzed with a dietary history interview; activity patterns were analyzed with an activity interview and body fat was measured with bioelectrical impedance analysis.

RESULTS

The obese subjects consumed significantly more total calories, total fat in grams and saturated fatty acids (SFA) in grams than did the non-obese subjects. Based on step-wise multiple regression, the total energy consumed, not total fat or SFA, had the strongest relationship to the subject's percentage body fat, controlling for activity levels.

CONCLUSION

We suggest that, although obese children and adolescents consume more dietary energy and fat than non-obese children and adolescents, there is a stronger relationship between total energy consumed and juvenile adiposity than with dietary fat or type of dietary fat consumed.