Mortimer, Joanne

635 Background: Prospective data on efficacy, quality of life, and treatment-related toxicities in older adults with breast cancer are limited. The ATOP trial (NCT03587740) evaluated T-DM1 in older adults and demonstrated favorable 5-year invasive disease-free survival. Here, we report patient-reported adverse events (AEs) and health-related quality of life (HRQOL) findings from ATOP. Methods: ATOP was a single-arm, phase II, multicenter study of adjuvant T-DM1 for those aged 60 with stage I-III HER2+ breast cancer. Protocol therapy included postoperative administration of T-DM1 (3.6 mg/kg) every 21 days for one year (17 cycles). PRO-CTCAE (assessing specific symptoms) and EQ-5D (a measure of HRQOL) surveys were administered electronically or on paper at baseline (pre-treatment), on Day 1 of each treatment cycle, and at a single 6–12-month post-treatment time point. Participants who responded to the baseline and at least one follow-up survey were included in the PRO analysis. EQ-5D changes from baseline were assessed using general linear mixed models. Summary statistics were used to assess PRO-CTCAE scores to evaluate which symptoms developed between baseline and 1 subsequent survey(s) and their severity. Results: Among the 111 patients enrolled on ATOP (median age=71, range 60-88 years), 98 responded to the baseline survey and 1 subsequent survey(s). 1435 surveys were returned that included at least one PRO-CTCAE response, and 1661 surveys were returned that included EQ-5D. The Table displays the % of participants who reported PRO-CTCAE symptoms that worsened from baseline to any severity level (scores >0) or to a severe level (scores ≥3). More than 60% of survey respondents reported new or increased dry mouth, fatigue, muscle aches, decreased appetite, nausea, pain, and/or numbness/tingling at some point during or after treatment, but these were usually not severe. EQ-5D scores did not change significantly from baseline at any time point. Conclusions: In this adjuvant trial for patients aged >60, participation rates for PRO data collection were high. Reassuringly, global HRQOL was not impacted by T-DM1, and though frequently reported, the vast majority of patient-reported symptoms were mild. Future analyses of this trial will focus on duration and predictors (clinical and biomarker-based) of severe AEs, agreement between patient-reported and clinician-reported AEs, and whether sharing PRO reports with clinicians impacted clinician-reported AE grades. Clinical trial information: NCT03587740 . Most common new or worsening symptoms reported via PRO-CTCAE in ATOP (n=95). Symptom % with score >0 n (%) with score 3+ Dry mouth 79% 26% Fatigue 71% 29% Muscle aches 69% 20% Decreased appetite 69% 12% Nausea 67% 6% Pain 66% 21% Numbness/tingling 65% 9% Blurry vision 60% 4% Mouth or throat sores 60% 5%

536 Background: Folate receptor alpha (FRα) is overexpressed in ~80% of triple-negative breast cancers (TNBC). We previously demonstrated that patients (pts) with breast cancer naturally mount immune responses to FRα. In prior Phase I and II studies, a GM-CSF-adjuvanted FRα peptide vaccine (FRPV) was safe and induced durable FRα-specific T-cell immunity in 83–90% of pts with breast and ovarian cancer. Methods: Eligible pts were women ≥18 years with TNBC (ER/PR ≤10%) with 1+ of the following: stage ≥T1c disease, node-positivity, or residual disease after neoadjuvant chemotherapy. Pts were randomized 2:1 to receive FRPV or placebo (GM-CSF alone) every 28 days for cycles 2-7 and then every six months for 7 booster doses, with cycle 1 consisting of cyclophosphamide 50mg orally twice daily for days 1-7 and 15-21 (in both arms). Randomization was stratified by chemotherapy setting (adjuvant only vs neoadjuvant) and stage (I/II vs III). FRα expression was evaluated by immunohistochemistry. The study was designed to detect (at 30 months after the last pt enrolled) a disease-free survival (DFS) difference of 14% assuming a 3.5-year DFS rate of 70% in the control group and with 78% power. Results: 280 pts were enrolled (median age 52). The majority had stage I or II tumors (n = 219, 78%). There were numerically more node-positive tumors in the vaccine arm, 78 (41%) vs 27 (32%), p = 0.15. Median follow-up was 3.5 years, and 33 (FRPV: 25, placebo: 8) DFS events were observed; 3.5-year DFS rate was 88% with FRPV and 90% with placebo (HR 1.42, 95% CI 0.64–3.15; p = 0.39). Overall survival (OS) also did not differ by arm (HR 2.48, 95% CI 0.55–11.20; p = 0.22). Among node-positive pts (n = 105), DFS did not differ between arms (HR 0.95, 95% CI 0.34–2.66; p = 0.92). However, a numerical DFS event rate improvement (14% for vaccine vs. 26% for placebo) was observed in 61 patients with stage III disease (HR 0.51, 95% CI 0.16–1.68; p = 0.26). DFS did not differ by chemotherapy setting or by receipt of anthracycline, capecitabine, and/or an immune checkpoint inhibitor. FRPV was well tolerated, with predominantly grade 1–2 adverse events (AEs) and no vaccine-related grade ≥4 AEs. FRα expression was available from tumor in 230 pts, with 72% expressing > 0. Overall, DFS was not significantly associated with FRα expression (0 vs > 0; HR 0.55, 95% CI 0.21–1.44; p = 0.21), and no significant differences in DFS by FRα expression were observed between treatment arms. Conclusions: FRPV following oral cyclophosphamide was safe, with no vaccine-related high-grade AEs. While no significant improvement in DFS or OS was observed overall, a numeric trend toward improved DFS was observed in pts with stage III TNBC. This finding is hypothesis-generating and supports further evaluation of FRα-targeted vaccination in higher-risk TNBC. Immune correlative analyses are ongoing to better define vaccine immunogenicity and its relationship to clinical outcomes. Clinical trial information: W81XWH-15-1-0293.

The treatment landscape of invasive early-stage and metastatic breast cancer is evolving constantly. These NCCN Guidelines Insights focus on recent updates included in the most recent version (version 5.2025) of the NCCN Guidelines for Breast Cancer specific to workup, locoregional therapy, surveillance, and systemic neoadjuvant/adjuvant therapy recommendations for invasive, nonmetastatic breast cancer.

1015 Background: T-DXd is an antibody-drug conjugate approved for advanced HER2+/low/ultra-low breast cancer and multiple other solid tumors. T-DXd carries a rare but serious risk of ILD (incidence 12-15%), requiring frequent imaging and symptom evaluation. For > grade (G) 2 ILD, guidelines recommend permanent drug discontinuation. For asymptomatic G1 ILD, drug is held with the option for rechallenge (RC) if imaging findings resolve. Limited data exist on outcomes of RC after ILD in diverse real-world patients (pts). Methods: In this multi-center retrospective study, we analyzed pts with T-DXd related ILD treated from 2017-2024. Pts with ILD were identified via chart/ICD code review. Adjudication of T-DXd related ILD was based on treating providers’ assessment and graded via CTCAE v5. We collected pt demographics, T-DXd and steroid dosing, imaging results, and outcomes after RC. Statistical analysis was performed using Wilcoxon rank sum and Fisher’s exact tests. Results: Four centers treated 712 pts with T-DXd, with a 9.1% rate of any grade ILD (n=65). One other center reported only RC data in 18 pts with ILD. In total, 47 pts were RC; 38 after G1 ILD (81%), 9 after G2. Median (med) time to initial ILD was 145 days (d) after 1st dose (interquartile range [IQR] 78-205). Demographics for pts RC are shown in the table. Among 50 pts with G1 ILD, including pts not RC, 28/50 (56%) received steroids for a med of 36d (IQR 27-79). Radiographic improvement was seen at a med of 24d (IQR 19-63) for pts treated with steroids vs 82d (IQR 48-94) without (p<0.01); and a med of 35d (IQR 22-82) for pts RC vs 81d (IQR 68-105) for pts not RC (p=0.01). Among pts with G1 ILD, 38/50 (76%) were RC at a med of 42d (IQR 36-57) from last dose; 23/38 (61%) were dose reduced. After RC, pts remained on T-DXd for a med of 215d (IQR 60-334); 10/38 (26%) developed recurrent ILD (7-G1, 2-G2, 1-G3) at a med of 211d (IQR 47-273) from RC. No statistically significant differences were seen between ILD onset, time to RC, or demographics for pts with recurrent ILD vs not. Of the 9 pts RC after G2 ILD, T-DXd was continued for a med of 129d (IQR 49-171); 2/9 (22%) developed recurrent ILD (1-G2, 1-G3). No G5 toxicity was seen with RC. Conclusions: In this multi-center study, high RC rates were seen after G1 ILD with long duration of clinical benefit. Pts treated with steroids had faster radiographic ILD improvement, highlighting the importance of early steroid use. Among pts RC after G1 ILD, recurrent ILD rates were low, with the majority G1 and no G5 events. Notably, 9 pts with G2 ILD were RC, with a similar rate of recurrent ILD; this must be interpreted cautiously. Our large cohort data further supports the safety of T-DXd RC in diverse real-world settings. RC Pt Characteristics (n=47) n (%) or Median (IQR) Cancer typeBreastGIGyn 43 (91)3 (6)1 (2) Age (yrs) 57 (52-68) Prior # therapy lines in the advanced/metastatic setting 3 (1-5) Renal impairment (CrCl < 60 mL/min) 8 (17)

Breast cancer is treated with a multidisciplinary approach involving surgical oncology, radiation oncology, and medical oncology. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer include recommendations for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget’s disease, Phyllodes tumor, inflammatory breast cancer, and management of breast cancer during pregnancy. The content featured in this issue focuses on the recommendations for overall management of systemic therapy (preoperative and adjuvant) options for nonmetastatic breast cancer. For the full version of the NCCN Guidelines for Breast Cancer, visit NCCN.org .

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer address all aspects of management for breast cancer. The treatment landscape of metastatic breast cancer is evolving constantly. The therapeutic strategy takes into consideration tumor biology, biomarkers, and other clinical factors. Due to the growing number of treatment options, if one option fails, there is usually another line of therapy available, providing meaningful improvements in survival. This NCCN Guidelines Insights report focuses on recent updates specific to systemic therapy recommendations for patients with stage IV (M1) disease.

5554 Background: Epithelial ovarian cancer (EOC) is characterized by chemoresistant recurrences primarily confined to the intraperitoneal cavity, frequently leading to malignant small bowel obstructions. Intraperitoneal (IP) chemotherapy has been incorporated in EOC, but only in the first-line setting. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel IP drug delivery method that optimizes tissue penetration depth and drug distribution, to treat recurrent peritoneal malignancies. Recent trials outside the U.S. demonstrated partial to stable response following PIPAC in recurrent EOC. To date, no clinical trials have been completed investigating the role of PIPAC in EOC in the United States. Methods: We performed a multicenter prospective phase I trial using IP cisplatin 10.5 mg/m2 and doxorubicin 2.1 mg/m2 via PIPAC at 6-week intervals. Patients were eligible if they had recurrent disease with peritoneal metastasis; extraperitoneal metastasis was allowed. The primary endpoint was dose-limiting toxicity (DLT). Secondary endpoints included progression free survival, PCI scoring, RECIST measurements, and quality of life (QoL). The patients with gastric and uterine cancers’ toxicity data were used but given inherent prognostic differences the treatment efficacy for these patients were not used in this analysis. Adverse event (AE) monitoring was graded using CTCAE spanning 18 weeks. Following completion of treatment (³2 PIPACs) patients were followed up every 12 weeks. QoL was measured using patient-reported assessments at 0, 6, 12, and 18 weeks. Baseline demographics were summarized. Mean change in PCI was calculated between cycle (C) 1 and 2, and cycle 2 and 3. Toxicities attributed to the surgery or PIPAC were reported with highest grade for each patient. Results: Nine heavily pretreated, recurrent patients were enrolled in the trial: 7 with platinum-resistant recurrent EOC, 1 with uterine cancer, and 1 with gastric cancer. PIPAC completion rate was 71.4%. Median age of participants was 65 years. Median prior lines of chemotherapy were 4 (range 2 - 10). No surgical complications occurred in the cohort. Two patients came off study: one for G3 abdominal pain and the other for G3 anorexia. For the EOC cohort, the median PCI reduction was -1.4% (C1 to C2) and -2.8% (C1 to C3). One low-grade serous EOC patient demonstrated a partial response based on RECIST criteria and received 6 cycles. Two EOC patients showed an initial response based on PCI reduction, but progressed following Cycle 2. Overall, QoL was stable. Conclusions: PIPAC with cisplatin/doxorubicin in platinum-resistant ovarian cancer is well tolerated. Intraperitoneal responses were seen in a subset of low-grade serous ovarian cancer patients, which may warrant further study. Heavily pretreated, platinum-resistant high-grade EOC patients derived limited intraperitoneal control from PIPAC monotherapy. Clinical trial information: NCT04329494 .

The therapeutic options for patients with noninvasive or invasive breast cancer are complex and varied. These NCCN Clinical Practice Guidelines for Breast Cancer include recommendations for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, and management of breast cancer during pregnancy. The content featured in this issue focuses on the recommendations for overall management of ductal carcinoma in situ and the workup and locoregional management of early stage invasive breast cancer. For the full version of the NCCN Guidelines for Breast Cancer, visit NCCN.org .

The NCCN Guidelines for Breast Cancer include up-to-date guidelines for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, male breast cancer, and breast cancer during pregnancy. These guidelines are developed by a multidisciplinary panel of representatives from NCCN Member Institutions with breast cancer–focused expertise in the fields of medical oncology, surgical oncology, radiation oncology, pathology, reconstructive surgery, and patient advocacy. These NCCN Guidelines Insights focus on the most recent updates to recommendations for adjuvant systemic therapy in patients with nonmetastatic, early-stage, hormone receptor–positive, HER2-negative breast cancer.

Several new systemic therapy options have become available for patients with metastatic breast cancer, which have led to improvements in survival. In addition to patient and clinical factors, the treatment selection primarily depends on the tumor biology (hormone-receptor status and HER2-status). The NCCN Guidelines specific to the workup and treatment of patients with recurrent/stage IV breast cancer are discussed in this article.