Citations

Abstract Purpose: CD4 T-cell immunity is associated with improved survival in patients with breast cancer. We previously reported a phase I trial evaluating a folate receptor alpha (FRα) vaccine administered with cyclophosphamide (CP), demonstrating excellent safety and immunogenicity. To simplify the vaccine strategy for ease of use, we report here the results of a randomized phase II trial evaluating a lower vaccine dose alongside the original dose, administered with or without CP pretreatment. Patients and Methods: Patients with triple-negative breast cancer who completed all systemic and local therapies were assigned to receive either low-dose (825 μg) or high-dose (2.5 mg) vaccine peptides plus GM-CSF in six 4-week cycles, with or without CP prior to vaccination. Safety was monitored, and immunogenicity was evaluated before and after vaccination. Results: A total of 80 patients were dosed with vaccine, and 58 patients were evaluable for immunogenicity. Vaccination was well tolerated and elicited immunity in 83% of patients. Levels of FRα-specific T cells were high, persistent, and comparable with T-cell levels against tetanus toxoid. No differences in immunity were observed between the two doses. CP pretreatment also did not affect the immune responses. Recurrences occurred in eight evaluable patients and were unrelated to the treatment arm. No patients died during the study because of their disease. Conclusions: The reduced-dose FRα vaccine is as effective as the original dose and does not require CP to generate maximal immunity. These findings may inform the design of trials testing efficacy in triple-negative breast cancer or other cancers.

Abstract The highest risk for liver allograft rejection is within the first weeks to months after a liver transplant; however, while later-stage mechanisms are well described, the initial window at the moment of alloantigen influx (e.g., ~ 1 h post-reperfusion) remains unmapped. T-cell priming is initiated in lymph nodes, yet these sites are rarely profiled in humans and their relationship to rejection risk is unclear. To address this gap, we profiled paired pre- and ~ 1 h post-reperfusion hepatic draining lymph nodes from liver transplant recipients using multiplexed immunofluorescence and GeoMx whole-transcriptome profiling to identify features that predict rejection versus non-rejection. Early after reperfusion, CD4 + and CD8 + T cells became proximal to macrophages in rejection compared to dendritic cells in non-rejection, which also displayed an immunoregulatory-leaning profile marked by PD-1, IDO1, and CD39, suggesting that macrophages and dendritic cells differentially influence early T-cell alloimmunity. These results provide nodal targets for precise immune modulation.

569 Background: Several studies established the prognostic role of both the amount and locations of tumor-infiltrating lymphocytes (TILs) in TNBC. Three distinct immunotypes were described based on the amount and locations of TILs: immune enriched (IN), immune excluded, and immune desert. Using single-cell spatial transcriptomic analysis in the Mayo Clinic TNBC cohort, our previous studies showed the central role of interferon (IFN) signaling in IN phenotype. Herein, we evaluated the association between IFN and outcomes in TNBC in 3 independent datasets. Methods: NanoString IO360 was performed in 114 samples from FinXX (NCT00114816) to generate 22-gene IFNα and 33-gene IFNγ signatures. RNA sequencing was performed in 388 samples from CALGB 40603 (NCT00861705). 3038 TNBC samples were tested by WTS (NovaSeq; Caris Life Sciences, Phoenix, AZ). Median values were used as cut-offs for high vs low IFNγ RNA expression and 18-gene IFNγ signature scores. Caris Life Science CODEai was used to evaluate real-world overall survival (OS) obtained from insurance claims and calculated from tissue collection to last contact using Kaplan-Meier estimates. Chi-square, Mann-Whitney U, ANOVA, and Cox regression were used. Results: A high 22-gene IFNα signature score was associated with significantly improved recurrence-free survival (RFS) in FinXX (hazard ratio [HR] 0.32, 95% confidence interval [CI] 0.14-0.74, p 0.007) and OS (HR 0.28, 95%CI 0.12-0.66, p 0.003). Similar findings were observed with 33-gene IFNγ signature with significant improvement in RFS (HR 0.21, 95%CI 0.09-0.51, p < 0.001) and OS (HR 0.18, 95%CI 0.08-0.44, p < 0.001). Furthermore, in CALGB 40603, both IFNα and IFNγ scores were positively associated with pathologic complete response (pCR: IFNα p 0.019 and IFNγ p 0.007) and residual cancer burden (RCB: IFNα p 0.044 and IFNγ p 0.013). Using the Caris data platform to further validate, we identified 2899 TNBC patients (pts) with genomic and clinical outcome data. High IFNγ expression was associated with significant improvement in OS (25.95 vs 17.43 months; HR 0.65, 95% CI 0.59 – 0.72, p < 0.001). Similarly, pts with high IFNγ signature scores had significant improvement in median OS (25.79 vs 16.22 months; HR 0.66, 95% CI 0.6 – 0.73, p < 0.001). Conclusions: This study underscores the pivotal role of IFN signaling in TNBC. High IFNα and IFNγ signatures were consistently associated with improved RFS, OS, higher pCR rates, and lower RCB across clinical trial cohorts and real-world data. These findings signify IFN signaling as a potential key biomarker and therapeutic target in TNBC. Support: U10CA180821, U10CA180882, U24CA196171; Breast Cancer Research Foundation, Mayo Clinic Breast Cancer SPORE (P50CA116201-17), Bankhead Coley, W81XWH-15-1-0292, P50CA015083, R35CA253187; https://acknowledgments.alliancefound.org . Genentech. Clinical trial information: NCT00114816 and NCT00861705 .

Abstract Purpose: While an addition of immune checkpoint inhibitor (ICI), pembrolizumab, has improved outcomes of patients with TNBC, early-stage TNBC patients with residual cancer burden (RCB) II/III after neoadjuvant chemotherapy in combination with pembrolizumab (NAP) still have poor outcomes. Previously, we demonstrated that intratumoral HLA-DRA expression and interferon-alpha (IFNα) responses were associated with immune-inflamed phenotype and better outcomes in TNBC patients receiving chemotherapy. This study utilized the CosMx™ SMI to investigate in early-stage TNBC treated with NAP. Methods: Of 151 samples from TNBC patients treated with NAP at Mayo Clinic, 8 pre-treatment biopsy samples (5 pCR and 3 RCB II/III were analyzed using the CosMx™ SMI platform. Linear mixed models to assess differential expression (DE), adjusting for hierarchical data structures. DE analyses were expressed as log2-fold changes (logFC), with the Benjamini-Yekutieli method. GSEA and IPA for signaling pathway exploration. Results: 1.7 million cells were identified across 8 samples after stringent quality control. Immune cell profiling revealed higher B cells, plasma cells, plasmablasts, and T cells (CD4 and CD8) in responders, whereas fibroblasts and myeloid cells were enriched in non-responders. DE analysis showed significantly elevated expression of HLA-DRA (logFC 1.955, p&lt;0.001), other MHC class I and II components, and IFNα in responders. Tumor cells in responders exhibited the highest IFNα expression across cell types. GSEA and IPA analysis revealed enrichment in interferon signaling, antigen presentation, and the cGAS-STING pathway, which drives IFNα production. Spatial analysis categorized cells by their proximity to tumor cells: within 50 µm, 50-100 µm, and over 100 µm. T cells, particularly CD8 T cells, showed a distance-dependent distribution, with a higher abundance near tumor cells in responders. CD8 T cell activation scores declined with increasing distance from IFNα-positive tumor cells but remained consistently low near IFNα-negative tumor cells. IFNγ-positive CD8 T cells exhibited higher activation compared to IFNγ-negative cells, with activation levels influenced by proximity to tumor cells. Lastly, MHC expression in tumor cells was examined relative to CD8 T cell proximity. HLA-DRA and CIITA expression decreased as tumor cells were farther from CD8 T cells. Conclusions: This spatially resolved single-cell analysis highlights the pivotal role of tumor-immune interactions in response to pembrolizumab in TNBC. Our data suggest that tumor cells secrete IFNα through the activation of the cGAS-STING pathway, which activates T cells within close proximity, highlighting the potential role of cGAS-STING agonist as well as IFNα signaling and antigen presentation in augmenting TNBC responses to ICIs. Citation Format: Yi Liu, Saranya Chumsri, Yaohua Ma, Jodi M. Carter, Aziza Nassar, Edith Perez, Roberto A. Leon-Ferre, David Zahrieh, David W. Hillman, Judy C. Boughey, James Ingle, Krishna R. Kalari, Fergus J. Couch, Matthew P. Goetz, Keith L. Knutson, E. Aubrey Thompson. Spatially resolved single-cell analysis reveals cGAS-STING-mediated tumor-immune interactions via IFNα as determinants of pembrolizumab sensitivity in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7130.

Abstract Purpose: Activation of the RAS/MAPK pathway is associated with reduced tumor-infiltrating lymphocytes and poor outcomes in triple-negative breast cancer. Previous studies demonstrated that inhibition of the MAPK pathway with a MEK inhibitor is synergistic with immune checkpoint inhibitors. Patients and Methods: We conducted a phase I/II trial of pembrolizumab and binimetinib in patients with metastatic triple-negative breast cancer with ≤3 prior lines of therapy. There were two dose levels (DL) with binimetinib at 45 mg at DL 0 and 30 mg at DL −1. Results: The recommended phase II dose was the standard dose of pembrolizumab with binimetinib 30 mg twice daily. The objective response rate (ORR) was 30.4%, with a numerically higher ORR in patients without liver metastasis at 45.5%. Among patients who achieved objective responses, 80% had a duration of response &gt;12 months and ongoing even after stopping treatment (5.4–69.0 months). Patients with PD-L1–positive tumors (modified proportion score ≥10) were more likely to respond with an ORR of 66.7%. However, clinical benefit was observed in 25% of patients with PD-L1–negative tumors. Consistent with preclinical studies, four of six patients with clinical benefit had either increased PD-L1 or decreased p-ERK expressions in serial circulating cancer-associated macrophage-like cells after starting binimetinib. Conclusions: Pembrolizumab and binimetinib at 30 mg are safe with manageable toxicities. Promising activity was observed in patients without liver metastases. Future larger clinical trials are warranted to further evaluate the efficacy of this chemotherapy-free combination.

537 Background: Translocation renal cell carcinoma (tRCC) is a rare renal cell carcinoma subtype found in about 1-4% of adult patients with RCC and 40% of pediatric RCC cases. Management of advanced tRCC has been guided by clear cell RCC therapy and retrospective reviews which include tRCC cohorts. Novel therapeutic strategies are needed to improve outcomes. This study assessed an individualized neoantigen vaccine with nivolumab plus cabozantinib in a patient with metastatic TFE3-tRCC. Methods: Patient was consented (IRB# 20-011945) for a single-patient investigational new drug (IND#27755). In-house neoantigen prediction bioinformatics pipeline (REAL-neo v2.0) was performed to identify and prioritize neoantigen candidates. Patient underwent lymphodepletion with cyclophosphamide followed by vaccine administration on days 1, 4, 8, 11, 20, 40, week 12, and week 20. Patient was also treated with concurrent nivolumab 480 mg every 4 weeks and cabozantinib 40 mg daily. Objective response rate (ORR) and progression-free survival (PFS) were measured. Results: Patient was diagnosed with TFE3-tRCC and underwent nephrectomy prior to developing metastatic disease. He was treated with multiple liver surgeries, ablations, and radiation therapy without systemic therapy. This controlled his disease for 7 years before he required systemic therapy with ipilimumab plus nivolumab. After 4 cycles, imaging showed progression and was started on cabozantinib which controlled his disease for 1 year. Patient was consented for the neoantigen vaccine. Cycle 1 was administered in April 2022. Three liver lesions and 1 periportal lymph node were monitored. After 4 months of therapy, imaging showed partial response with 34% decrease in sum of target lesions. In June 2023, partial response was ongoing with a 57.4% decrease. A 2 nd vaccine series was administered in June 2023 and had stable disease until progression in June 2024 when patient held his cabozantinib for at least 4 weeks. Neoantigen combination therapy achieved a progression-free survival of 26 months and was well tolerated without significant vaccine-related adverse events. Conclusions: Individualized neoantigen vaccine plus nivolumab and cabozantinib achieved a durable partial response with prolonged progression-free survival. A randomized clinical trial is warranted to further evaluate the efficacy of this combination therapy.

Background: Remote patient monitoring (RPM) is an emerging focus in health care, and specialized programs may reduce medical costs, supplement in-office visits, and improve patient satisfaction. In this study, we describe the development, feasibility, and early outcomes of an RPM program for patients with decompensated cirrhosis. Methods: Forty-six patients were offered enrollment at the time of hospital discharge in the cirrhosis RPM program (CiRPM), of which 41 completed at least 30 days of monitoring. Participants were mailed remote monitoring equipment and a tablet to be used for patient-reported outcomes. Alerts were continuously monitored by virtual nursing staff who could perform targeted interventions. A cohort of historical controls (n = 74) was created for comparison using inverse probability of treatment weighting. Results: Patients were enrolled in the program for a mean of 83.9 days, with 28 (68%) completing the full 90-day program. Participants uploaded vital signs and responded to symptom-based questionnaires on 93% of the monitored days. On end-of-program surveys, over 75% of patients expressed satisfaction with the program. Gender, age, and MELD-Na were similar between CiRPM and weighted control groups. The 90-day readmission rate was 34% in CiRPM and 47% in weighted controls. In the CiRPM group, 12% of subjects had 2 or more admissions, compared to 37% in the weighted control group. Conclusion: This study demonstrates the feasibility of a cirrhosis-specific RPM program. Overall, patient satisfaction and utilization of the CiRPM was high. Future studies are needed to confirm the impact of RPM on the reduction of hospital readmissions in decompensated cirrhosis.