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PURPOSE The immunogenicity and reactogenicity of SARS-CoV-2 vaccines in patients with cancer are poorly understood. METHODS We performed a prospective cohort study of adults with solid-organ or hematologic cancers to evaluate anti–SARS-CoV-2 immunoglobulin A/M/G spike antibodies, neutralization, and reactogenicity ≥ 7 days following two doses of mRNA-1273, BNT162b2, or one dose of Ad26.COV2.S. We analyzed responses by multivariate regression and included data from 1,638 healthy controls, previously reported, for comparison. RESULTS Between April and July 2021, we enrolled 1,001 patients; 762 were eligible for analysis (656 had neutralization measured). mRNA-1273 was the most immunogenic (log10 geometric mean concentration [GMC] 2.9, log10 geometric mean neutralization titer [GMT] 2.3), followed by BNT162b2 (GMC 2.4; GMT 1.9) and Ad26.COV2.S (GMC 1.5; GMT 1.4; P < .001). The proportion of low neutralization (< 20% of convalescent titers) among Ad26.COV2.S recipients was 69.9%. Prior COVID-19 infection (in 7.1% of the cohort) was associated with higher responses ( P < .001). Antibody titers and neutralization were quantitatively lower in patients with cancer than in comparable healthy controls, regardless of vaccine type ( P < .001). Receipt of chemotherapy in the prior year or current steroids were associated with lower antibody levels and immune checkpoint blockade with higher neutralization. Systemic reactogenicity varied by vaccine and correlated with immune responses ( P = .002 for concentration, P = .016 for neutralization). In 32 patients who received an additional vaccine dose, side effects were similar to prior doses, and 30 of 32 demonstrated increased antibody titers (GMC 1.05 before additional dose, 3.17 after dose). CONCLUSION Immune responses to SARS-CoV-2 vaccines are modestly impaired in patients with cancer. These data suggest utility of antibody testing to identify patients for whom additional vaccine doses may be effective and appropriate, although larger prospective studies are needed.

Purpose PI3K/AKT pathway alterations are frequent in hormone receptor-positive (HR+) breast cancers. IPATunity130 Cohort B investigated ipatasertib–paclitaxel in PI3K pathway-mutant HR+ unresectable locally advanced/metastatic breast cancer (aBC). Methods Cohort B of the randomized, double-blind, placebo-controlled, phase 3 IPATunity130 trial enrolled patients with HR+ HER2-negative PIK3CA/AKT1/PTEN-altered measurable aBC who were considered inappropriate for endocrine-based therapy (demonstrated insensitivity to endocrine therapy or visceral crisis) and were candidates for taxane monotherapy. Patients with prior chemotherapy for aBC or relapse 2, days 1, 8, 15), every 28 days until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS). Results Overall, 146 patients were randomized to ipatasertib–paclitaxel and 76 to placebo–paclitaxel. In both arms, median investigator-assessed PFS was 9.3 months (hazard ratio, 1.00, 95% CI 0.71–1.40) and the objective response rate was 47%. Median paclitaxel duration was 6.9 versus 8.8 months in the ipatasertib–paclitaxel versus placebo–paclitaxel arms, respectively; median ipatasertib/placebo duration was 8.0 versus 9.1 months, respectively. The most common grade ≥ 3 adverse events were diarrhea (12% with ipatasertib–paclitaxel vs 1% with placebo–paclitaxel), neutrophil count decreased (9% vs 7%), neutropenia (8% vs 9%), peripheral neuropathy (7% vs 3%), peripheral sensory neuropathy (3% vs 5%) and hypertension (1% vs 5%). Conclusion Adding ipatasertib to paclitaxel did not improve efficacy in PIK3CA/AKT1/PTEN-altered HR+ HER2-negative aBC. The ipatasertib–paclitaxel safety profile was consistent with each agent’s known adverse effects. Trial registration NCT03337724.

We evaluated the efficacy and safety of poly-(adenosine diphosphate-ribose) polymerase (PARP) 1 and 2 inhibitor veliparib and temozolomide in metastatic breast cancer patients with and without germline BRCA1/2 mutations. In this single-arm phase II trial, patients with metastatic breast cancer received veliparib 30 to 40 mg twice daily on days 1 to 7 with concurrent temozolomide 150 mg/m2 on days 1 to 5 of a 28-day cycle. The primary cohort was unselected for BRCA mutation status, and an expansion cohort enrolled only BRCA1/2 carriers. The primary endpoint was objective response rate (ORR) in each cohort. Secondary endpoints included progression-free survival (PFS), clinical benefit rate (CBR), and evaluation of safety and tolerability. In the primary cohort of 41 unselected patients, which included 9 BRCA mutation carriers, the ORR was 10% and clinical benefit rate at 4 months (CBR) was 27%. In the expansion cohort of 21 BRCA1/2 carriers, the ORR was 14% and CBR was 43%. Among all 30 BRCA1/2 carriers, the ORR was 23% versus 0% among non-carriers. In the subset of BRCA1/2 carriers, the ORR was 32% among platinum-naive patients versus 9% among platinum-exposed patients. The median PFS was 3.3 months among BRCA1/2 carriers compared to 1.8 months among non-carriers (HR: 0.48, p = 0.006). A longer median PFS of 6.2 months was observed among BRCA1/2 carriers who had no prior platinum therapy. The most common grade 3 and 4 toxicities were thrombocytopenia (32%) and neutropenia (21%) that generally improved with dose modifications. Veliparib and temozolomide demonstrated clinical activity in platinum-naive BRCA-associated metastatic breast cancer with manageable toxicity at doses of veliparib well below the single-agent active dose. Although the study did not meet its primary endpoint in unselected nor BRCA-associated breast cancer, this regimen was further evaluated in the BROCADE 2 study. NCT01009788 (ClinicalTrials.gov), November 9, 2009

There are limited data on trastuzumab–pertuzumab (HP)-based treatments beyond the first-line, HER2+ metastatic breast cancer (MBC) setting. We conducted a phase II study of eribulin mesylate, which extends survival in MBC, with HP in patients with previously treated HER2+ MBC to evaluate efficacy, toxicity, and genomic alterations driving therapeutic response. After a run-in phase for eribulin dosing, two cohorts were enrolled (Cohort A-no prior pertuzumab; Cohort B-prior pertuzumab). All patients received eribulin 1.4 mg/m2 on days 1, 8 with standard-dose HP on day 1 (21-day cycles). The primary endpoint was objective response rate (ORR). Genomic characterization via whole exome sequencing (WES) was completed on tumor DNA and matched germline DNA from 19 patients. The six-patient run-in established a dose of eribulin 1.4 mg/m2 with HP. Cohorts A and B enrolled 17 and 7 patients, respectively. Accrual stopped early due to an evolving treatment landscape and slow enrollment. The ORR was 26.3% (95% Confidence Interval [CI] 9.2–51.2%) in Cohort A and 0% in Cohort B (95% CI 0–41.0%). WES revealed more frequent alterations in TP53 (p 0.05) in patients without clinical benefit (disease control for

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.

Purpose: Plasma genotyping may identify mutations in potentially “actionable” cancer genes, such as BRCA1/2, but their clinical significance is not well-defined. We evaluated the characteristics of somatically acquired BRCA1/2 mutations in patients with metastatic breast cancer (MBC). Experimental Design: Patients with MBC undergoing routine cell-free DNA (cfDNA) next-generation sequencing (73-gene panel) before starting a new therapy were included. Somatic BRCA1/2 mutations were classified as known germline pathogenic mutations or novel variants, and linked to clinicopathologic characteristics. The effect of the PARP inhibitor, olaparib, was assessed in vitro, using cultured circulating tumor cells (CTCs) from a patient with a somatically acquired BRCA1 mutation and a second patient with an acquired BRCA2 mutation. Results: Among 215 patients with MBC, 29 (13.5%) had somatic cfDNA BRCA1/2 mutations [nine (4%) known germline pathogenic and rest (9%) novel variants]. Known germline pathogenic BRCA1/2 mutations were common in younger patients (P = 0.008), those with triple-negative disease (P = 0.022), and they were more likely to be protein-truncating alterations and be associated with TP53 mutations. Functional analysis of a CTC culture harboring a somatic BRCA1 mutation demonstrated high sensitivity to PARP inhibition, while another CTC culture harboring a somatic BRCA2 mutation showed no differential sensitivity. Across the entire cohort, APOBEC mutational signatures (COSMIC Signatures 2 and 13) and the “BRCA” mutational signature (COSMIC Signature 3) were present in BRCA1/2-mutant and wild-type cases, demonstrating the high mutational burden associated with advanced MBC. Conclusions: Somatic BRCA1/2 mutations are readily detectable in MBC by cfDNA analysis, and may be present as both known germline pathogenic and novel variants.

Purpose During the COVID-19 pandemic, most breast surgery for benign and malignant conditions has been postponed, creating a backlog of patients who will need surgery. A fair and transparent system for assessing the risk of further delaying surgery for individual patients to prioritize surgical scheduling is needed. Methods Factors related to risk of delaying surgery for breast patients were identified. Scores were assigned to each factor, with higher scores indicating a greater risk from delaying surgery. REDCap and Microsoft Excel tools were designed to track and score delayed patients. Results Published data and multidisciplinary clinical judgement were used to assign risk scores based on patient and tumor factors, length of delay, and tumor response to preoperative therapy. Patients completing neoadjuvant chemotherapy were assigned the highest scores as their options for delaying surgery are most limited. Among patients receiving neoadjuvant endocrine therapy or no medical therapy, higher scores were assigned for low-estrogen receptor or high-genomic risk scores, higher grade, larger tumors, younger age and longer delay. High priority scores were assigned for progression during preoperative therapy. Low scores were assigned for re-excisions, atypical lesions and other benign indications. There was good agreement of the tool’s ranking of sample patients with rankings by experienced clinicians. The tool generates risk-stratified patient lists by surgeon or institution to facilitate assignment of surgery dates. Conclusions This tool generates a clinically consistent, risk-stratified priority list of breast surgical procedures delayed by the COVID-19 pandemic. This systematic approach may facilitate surgical scheduling as conditions normalize.

A Woman with Early Breast Cancer during the Covid-19 Pandemic A 62-year-old woman was evaluated for a mass that had been identified in the left breast during the Covid-19 pandemic. Mammography reve...

Purpose: Patients with triple-negative breast cancer (TNBC) with homologous recombination deficient tumors achieve significantly higher pathologic complete response (pCR) rates when treated with neoadjuvant platinum-based therapy. Tumor-infiltrating lymphocytes (TIL) are prognostic and predictive of chemotherapy benefit in early stage TNBC. The relationship between TILs, BRCA1/2 mutation status, and homologous recombination deficiency (HRD) status in TNBC remains unclear. Experimental Design: We performed a pooled analysis of five phase II studies that included patients with TNBC treated with neoadjuvant platinum-based chemotherapy to evaluate the association of TILs with HRD status (Myriad Genetics) and tumor BRCA1/2 mutation status. Furthermore, the relationship between pathologic response assessed using the residual cancer burden (RCB) index and HRD status with adjustment for TILs was evaluated. Results: Among 161 patients, stromal TIL (sTIL) density was not significantly associated with HRD status (P = 0.107) or tumor BRCA1/2 mutation status (P = 0.391). In multivariate analyses, sTIL density [OR, 1.23; 95% confidence interval (CI), 0.94–1.61; P = 0.139] was not associated with pCR, but was associated with RCB 0/I status (OR 1.62; 95% CI, 1.20–2.28; P = 0.001). HRD was significantly associated with both pCR (OR 12.09; 95% CI, 4.11–44.29; P = 7.82 × 10−7) and RCB 0/I (OR 10.22; 95% CI, 4.11–28.75; P = 1.09 × 10−7) in these models. Conclusions: In patients with TNBC treated with neoadjuvant platinum-based therapy, TIL density was not significantly associated with either tumor BRCA1/2 mutation status or HRD status. In this pooled analysis, HRD and sTIL density were independently associated with treatment response, with HRD status being the strongest predictor.

PURPOSE Platinum compounds have activity in triple-negative breast cancer (TNBC) in germline BRCA mutation carriers ( BRCA carriers). Limited data exist for estrogen receptor (ER)–positive (+) breast cancer among BRCA carriers. INFORM is a randomized, multicenter, phase II trial comparing pathologic complete response (pCR) rates (ypT0/is, N0) after neoadjuvant single-agent cisplatin (CDDP) versus doxorubicin-cyclophosphamide (AC) in BRCA carriers with stage I-III human epidermal growth factor receptor 2 (HER2)–negative breast cancer. Secondary objectives included residual cancer burden scores (RCB) of 0 or 1 (combined) and toxicity. The goal was to determine whether pCR was ≥ 20% higher with CDDP than AC. PATIENTS AND METHODS BRCA carriers with cT1-3 (≥ 1.5 cm), cN0-3 HER2-negative breast cancer were randomly assigned to preoperative CDDP (75 mg/m2 every 3 weeks × 4 doses) or AC (doxorubicin 60 mg/m2; cyclophosphamide 600 mg/m2 every 2-3 weeks × 4 doses) followed by surgery. Pathologic responses were confirmed by central review. RESULTS A total of 118 patients were randomly assigned; 117 were included in outcome analyses. Mean age was 42 years (range, 24-73 years); 69% were BRCA1+, 30% were BRCA2+, and 2% had both mutations. Clinical stage was I for 19%, II for 63%, and III for 18%; 45% had nodal involvement at baseline. Seventy percent had TNBC. Clinical and tumor characteristics were well matched between treatment arms. The pCR rate was 18% with CDDP and 26% with AC, yielding a risk ratio (RR) of 0.70 (90% CI, 0.39 to 1.2). The risk of RCB 0 or 1 (RCB 0/1) was 33% with CDDP and 46% with AC (RR, 0.73; 90% CI, 0.50 to 1.1). Both regimens were generally well tolerated without unexpected toxicities. CONCLUSION pCR or RCB 0/1 is not significantly higher with CDDP than with AC in BRCA carriers with stage I-III HER2-negative breast cancer for both TNBC and ER+/HER2-negative disease.

Inhibidor d'AKT; Càncer avançat; Fase I Inhibidor de AKT; Cáncer avanzado; Fase I AKT inhibitor; Advanced cancer; Phase I Background This phase Ib study evaluated the safety, tolerability, pharmacokinetics, and preliminary efficacy of the oral AKT inhibitor ipatasertib and chemotherapy or hormonal therapy in patients with advanced or metastatic solid tumors to determine combined dose-limiting toxicities (DLTs), maximum tolerated dose, and recommended phase II doses and schedules. Patients and methods The clinical study comprised four combination treatment arms: arm A (with docetaxel), arm B [with mFOLFOX6 (modified leucovorin, 5-fluorouracil, and oxaliplatin)], arm C (with paclitaxel), and arm D (with enzalutamide). Primary endpoints were safety and tolerability; secondary endpoints were pharmacokinetics, clinical activity per Response Evaluation Criteria in Solid Tumors v1.1, and prostate-specific antigen levels. Results In total, 122 patients were enrolled. Common adverse events were diarrhea, nausea, vomiting, decreased appetite, and fatigue. The safety profiles of the combination regimens were consistent with those of the background regimens, except for diarrhea, hyperglycemia, and rash, which were previously observed with ipatasertib treatment. The only combination DLT across all treatment arms was one event of grade 3 dehydration (ipatasertib 600 mg and paclitaxel). Recommended phase II doses for ipatasertib were 600 mg (and mFOLFOX6) and 400 mg (and paclitaxel), respectively. The maximum assessed dose of ipatasertib 600 mg combined with docetaxel or enzalutamide was well tolerated. Coadministration with enzalutamide (a cytochrome P450 3A inducer) resulted in approximately 50% lower ipatasertib exposure. Conclusions Ipatasertib in combination with chemotherapy or hormonal therapy was well tolerated with a safety profile consistent with that of ATP-competitive AKT inhibitors. This work was supported by Genentech, Inc., a member of the Roche Group, and F. Hoffmann-La Roche Ltd. (no grant number).

Background: Niraparib is a selective poly(ADP-ribose) polymerase 1/2 inhibitor that has demonstrated antitumor activity in advanced triple-negative breast cancer (TNBC) in combination with a programmed cell death 1 inhibitor, with the greatest clinical activity seen in tumors with breast cancer susceptibility gene (BRCA) mutations. Pharmacologically, niraparib has demonstrated a wide volume of distribution and high cell membrane permeability. In breast and ovarian cancer xenograft mouse models, niraparib achieved tumor exposures that were 3.3 times greater than plasma exposure. The objective of this study is to evaluate the antitumor activity of single-agent niraparib in the neoadjuvant treatment of patients with localized, human epidermal growth factor receptor 2 (HER2)-negative, BRCA-mutated breast cancer. The relative concentration of niraparib in tumor versus plasma was also assessed. Methods: Eligible patients were ≥18 years old, with HER2-negative, BRCA-mutated (germline or somatic) resectable breast cancer with a tumor size of ≥1 cm who had not received prior treatment for the current malignancy. Patients received niraparib 200 mg once daily for 2 months. At the end of 2 months, at their treating physician’s discretion, patients proceeded directly to surgery, received additional cycles of niraparib (maximum of 6 months), or received neoadjuvant chemotherapy. The primary endpoint was tumor response rate measured by magnetic resonance imaging (MRI) after 2 months of treatment. Response was defined as a ≥30% reduction in tumor volume from baseline. Secondary endpoints included tumor response rate measured by ultrasound, quantified percent change in tumor volume measured by MRI or ultrasound, pathological complete response, and safety and tolerability. Additionally, niraparib concentrations were measured in tumor and plasma samples using qualified liquid chromatography-tandem mass spectrometry. Results: Twenty-one patients were enrolled. As of June 2019, 18 patients had both an MRI and ultrasound scan at the end of month 2 and were evaluable for response. Ten patients are currently on treatment. The median age of patients was 43 years (range, 21-73). Fourteen patients had a BRCA1 mutation, 6 patients had a BRCA2 mutation, and 1 patient had both. Fifteen patients had TNBC, and 6 patients had hormone receptor-positive disease. All 18 response-evaluable patients had a clinical response after 2 months of treatment by at least one imaging modality; no patient experienced disease progression. Tumor response rate measured by MRI after 2 months of treatment was 89% (n/N = 16/18). Results measured by ultrasound were similar, with a 94% response rate at cycle 2 (n/N = 17/18). The median percent decrease in tumor volume after 2 months of treatment was 88% (range, 26-100%) and 89% (range, 23-100%) as measured by MRI and ultrasound, respectively. In the 5 samples measured thus far, niraparib concentrations in tumor biopsies after 2 months of treatment ranged from approximately 4-131-fold higher than those in corresponding plasma samples. Efficacy and tumor concentration data for all patients will be presented at the meeting. The most common (≥10%) drug-related treatment-emergent adverse events (TEAEs) of any grade were nausea, fatigue, anemia, insomnia, and decreased appetite. The only drug-related grade ≥3 toxicity in ≥10% of patients was anemia (3 patients). Three patients had a dose reduction due to a TEAE; no patient discontinued treatment due to a TEAE. Conclusion: Niraparib was well tolerated and showed promising antitumor activity in the neoadjuvant treatment of patients with localized HER2-negative, BRCA-mutated breast cancer. Niraparib achieved 4-131-fold higher concentrations in tumor than in plasma. Clinical trial information: NCT03329937. Funding: TESARO: A GSK Company (Waltham, MA, USA) sponsored the study. Citation Format: Hyo Han, Minetta C Liu, Erika Hamilton, Hanna Irie, Cesar A Santa-Maria, James Reeves, Andre Liem, Adrianna Milillo Naraine, Julie Nangia, David Page, Meghan Duncan, Ming Shan, Yongqiang Tang, Julie R Graham, Leif W Ellisen, Steven Isakoff, Laura Spring. Pilot neoadjuvant study of niraparib in HER2-negative, BRCA-mutated resectable breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-11-03.

Background: CRA is a surrogate for ovarian toxicity and associated risk of infertility and long-term menopausal symptoms. Therefore, it is important to assess and report the rate of CRA when we study a new neoadjuvant treatment regimen. In the Adjuvant Paclitaxel and Tratuzumab (APT) trial, we found that CRA rate associated with adjuvant TH (12 weeks of paclitaxel and a year of trastuzumab) for human epidermal growth factor receptor-2 (HER2)-positive breast cancer was lower than historically seen with cyclophosphamide-based regimens. The ATEMPT trial allowed a direct comparison of the CRA rate associated with TDM1 and TH. Methods: The ATEMPT trial randomized patients (pts) with Stage I HER2+ breast cancer 3:1 to T-DM1 3.6 mg/kg IV every 3 weeks (w) x17 vs. T 80 mg/m2 IV with H qw x 12 (4 mg/kg load →2 mg/kg), followed by H (6 mg/kg q3w x 13). Participants who reported that they were premenopausal at enrollment were asked to complete menstrual surveys at baseline and every 6-12 months throughout a 36 month follow-up period. For this analysis, CRA was defined as report of no menstruation within the prior six months on a survey completed 18 months after enrollment. Results: Of 512 ATEMPT enrollees, 497 began protocol therapy, 130 (26%) were premenopausal at enrollment and answered baseline menstrual questions, 42 of these 130 were excluded from the current analyses because they did not complete the 18-month survey, and 7 of the remaining 88 had received gonadotropin-releasing hormone agonist before 18 months, leaving 81 for analysis. None had undergone hysterectomy or oophorectomy. Median age was 44 (range 23-53) among the TH patients (n=20), and 46 (range 34-54) among the T-DM1 patients (n=61). On the 18-month survey, 45% of women treated with TH reported at least one one episode of menses during the prior 6 months compared to 75% of women in the T-DM1 arm (p=0.011). Among those ≤ 40 years old, 50% of TH patients and 100% of T-DM1 patients reported menstruation at that timepoint. Please see Table for additional data in subgroups. Conclusions: In this relatively small sample, CRA at 18 months was less common after adjuvant T-DM1 than after TH (though even with TH, nearly half of women did menstruate after chemotherapy, even in the subset aged 41+). This will be reassuring to young patients with HER2-positive breast cancer who seek to maintain ovarian function. Larger studies are needed to confirm this finding and to assess a possible differential impact of these drugs on subgroups based on age, endocrine therapy, and body mass index. Additional research should also focus on menopausal symptoms and actual fertility after receipt of T-DM1. Menstruation in 61 T-DM1 arm patients with informative surveys at 18 monthsMenstruation in 20 TH arm patients with informative surveys at 18 monthsAge at study entry95% CI95% CI≤4012/12 (100%)74-100%4/8 (50%)16-84%41+34/49 (69%)55-82%5/12 (42%)15-72%BMI Citation Format: Kathryn J. Ruddy, Lorenzo Trippa, Jiani Hu, William T. Barry, Chau T. Dang, Denise A. Yardley, Steven J. Isakoff, Vincente V. Valero, Meredith G. Faggen, Therese M. Mulvey, Ron Bose, Douglas J. Weckstein, Antonio C. Wolff, Katherine E. Reeder-Hayes, Hope S. Rugo, Bhuvaneswari Ramaswamy, Dan S. Zuckerman, Lowell L. Hart, Vijayakrishna K. Gadi, Michael Constantine, Kit L. Cheng, Frederick M. Briccetti, Bryan P. Schneider, A. Merrill Garrett, P. Kelly Marcom, Kathy S. Albain, Patricia A. DeFusco, Nadine M. Tung, Blair M. Ardman, Rita Nanda, Rachel C. Jankowitz, Michelle K. DeMeo, Harold J. Burstein, Eric P. Winer, Ian E. Krop, Ann H. Partridge, Sara M. Tolaney. Chemotherapy-related amenorrhea (CRA) after adjuvant trastuzumab emtansine (T-DM1) compared to paclitaxel in combination with trastuzumab (TH) (TBCRC033: ATEMPT trial) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-13-02.

Background: BM in MBC patients cause significant morbidity and mortality. BRCA1 germline mutations have previously been shown to be associated with an increased risk of developing BM (Lee et al, 2011), with an incidence as high as 15% (Zavitsanos et al, 2016). We previously reported that a subset of MBC patients may have somatic BRCA mutations in the absence of germline BRCA mutations (Vidula N, SABCS, 2017). In this study, we evaluated the incidence and clinical characteristics of BM in MBC patients with somatic BRCA mutations detected by cfDNA. Methods: MBC patients with somatic BRCA1 or 2 mutations detected by cfDNA (Guardant360TM, next generation sequencing, 73 gene panel; mutations classified as somatic by Guardant360TM) with at least 4 months of follow-up post-testing at an academic institution were identified. From this cohort, we identified patients who developed BM post cfDNA testing. A retrospective review of medical records and Guardant360TM reports was conducted to identify demographics, tumor subtype, type of cfDNA BRCA mutation, whether the BRCA mutation was known to be pathogenic, germline BRCA mutation status, mutant allele fraction (MAF), clonality (MAF ratio of BRCA mutation/gene mutation with highest MAF ≥ 0.25 for clonal, and Results: Of 36 MBC patients with somatic BRCA mutations, 9 (25%) developed BM and 27 (75%) did not have BM (non-BM). The median time to development of BM was 6.7 months after cfDNA testing. Of the BM patients, 5 (56%) had triple-negative (TN) and 4 (44%) had hormone receptor positive (HR+)/HER2- MBC in comparison with the non-BM cases where 5 (19%) had TN, 19 (70%) had HR+/HER2-, and 3 (11%) had HER2+ MBC. Very few patients (1 BM and 2 non-BM) had known co-existing separate germline BRCA mutations (rest not known BRCA carriers confirmed by negative germline testing and/or absence of family history suggestive of a germline BRCA phenotype). The median age at MBC diagnosis was similar for BM and non-BM patients (57 years). PIK3CA and TP53 mutations were commonly seen in both BM and non-BM cases. Additionally, MYC, EGFR, and CCNE1 mutations were commonly seen in BM cases. As outlined in Table 1, among patients with BM, the somatic BRCA mutations were commonly BRCA1, clonal, known to be pathogenic (56%), and present at a higher MAF, but these findings did not reach statistical significance possibly due to the small sample size. Brain tumor tissue mutation status in BM patients and correlation with cfDNA results will be presented at the meeting. Conclusions: We observed a relatively high incidence (25%) of BM in MBC patients with somatic BRCA mutations detectable by cfDNA, which were often known to be pathogenic mutations (56%), and often associated with co-existing MYC, EGFR, and CCNE1 mutations. Further research using a larger cohort with adequate statistical power is needed to validate these findings, and may help identify MBC patients at risk for BM using a liquid biopsy. Table 1.Characteristic BMNon-BMPrior anthracycline and/or platinum6 (67%)16 (59%)Type of somatic BRCA mutationBRCA16 (67%)11 (41%)BRCA22 (22%)15 (56%)BRCA1 and 21 (11%)1 (4%)Median BRCA MAF0.40.17ClonalityClonal6 (67%)13 (48%)Subclonal3 (33%)14 (52%)Mutation known to be pathogenic5 (56%)7 (26%)Common co-existing mutationsPIK3CA5 (56%)12 (44%)TP535 (56%)15 (56%)MYC5 (56%)8 (30%)EGFR5 (56%)8 (30%)CCNE15 (56%)6 (22%)KIT3 (33%)5 (19%) Citation Format: Neelima Vidula, Andrzej Niemierko, Giuliana Malvarosa, Priscilla Brastianos, Erica Blouch, Kristen Shannon, Steven Isakoff, Seth Wander, Laura Spring, Jerry Younger, Kristin Price, Beverly Moy, Dejan Juric, Leif Ellisen, Aditya Bardia. Brain metastases (BM) in patients with metastatic breast cancer (MBC) and circulating cell-free DNA (cfDNA) somatic BRCA mutations [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-09-06.

Background: The cyclin-dependent 4/6 inhibitors (CDK4/6i), in combination with an anti-estrogen, have emerged as the standard of care for patients with HR+/HER2- MBC. While only limited insight exists into the molecular factors that drive progression, emerging evidence suggests that activation of AKT1 may provoke resistance in a subset of patients. Overexpression of AKT1 also conveys resistance in HR+/HER2- breast cancer cells in vitro. AKT1 plays a well-established role in promoting tumor progression and metastasis. Targeting AKT1 following progression on CDK4/6i may provide durable clinical benefit in HR+/HER2- MBC. Trial Design: This is an open-label phase Ib trial with three arms - Arm A includes fulvestrant + ipatasertib and Arm B includes an aromatase inhibitor (AI) + ipatasertib. Arm C includes fulvestrant + ipatasertib + palbociclib. Arm A and B are dose-expansion cohorts while Arm C is a dose-escalation (standard 3+3 design) followed by subsequent dose-expansion. Eligibility Criteria: Key inclusion criteria include the presence of locally advanced/unresectable and metastatic HR+/HER2- breast cancer; postmenopausal status or pre/peri-menopausal status s/p oophrectomy or GNRH agonist; at least one prior therapy for MBC including any CDK4/6i; adequate performance status (ECOG 0-2); and adequate bone marrow and hepatic function. Stable CNS metastatic disease and up to two prior lines of chemotherapy for MBC are allowed (no limit on number of prior lines of endocrine therapy). Key exclusion criteria include prior use of fulvestrant (for Arm A); any prior intolerable toxicity with CDK4/6i (for Arm C); prior exposure to an AKT inhibitor in any setting; active CNS disease; concurrent use of specific CYP3A4 inhibitors or inducers; poorly controlled intercurrent illness; and pregnancy or active child-bearing potential. Specific Aims: The primary objective of this study is to evaluate the safety and tolerability of ipatasertib in combination with endocrine therapy (aromatase inhibitor or fulvestrant) with or without CDK4/6i in patients with HR+/HER2- MBC who have received prior CDK 4/6i. Secondary objectives include assessment of objective response rate (ORR), clinical benefit rate (CBR), and progression free survival (PFS). Exploratory objectives include next generation sequencing of solid tumor biopsies and cfDNA along with immunohistochemical analysis of tumor biopsies to identify genomic and protein-based predictors of response and resistance. Statistical Methods: Arms A and B constitute dose-expansion cohorts to confirm the safety/tolerability of ipatasertib use with anti-estrogens and evaluate preliminary efficacy. A dose-limiting toxicity (DLT) rate of Present and Target Accrual: Anticipated accrual for Arms A+B will be n=15 (each). Arm C enrollment will be n=15-30 pending establishment of RP2D/MTD prior to dose expansion. Current enrollment n=4, since study activation in May 2019. Citation Format: Seth A. Wander, Dejan Juric, Laura M. Spring, Neelima Vidula, Maureen Beeler, Karleen Habin, Elene Viscosi, Lauren Scarpetti, Elizabeth Tripp, Rachel Hepp, Beverly Moy, Steven J. Isakoff, Leif W. Ellisen, Aditya Bardia. A phase 1b trial to evaluate safety and anti-tumor activity of the AKT inhibitor, ipatasertib, in combination with endocrine therapy with/without CDK 4/6 inhibitor for patients with hormone receptor positive (HR+)/HER2 negative metastatic breast cancer (MBC) (TAKTIC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT2-08-01.

Background: The comprehensive analysis of clinically annotated tissue specimens from those with either benign, high risk or malignant breast findings is critical to improve the understanding of breast cancer biology and treatment. Through a multidisciplinary team approach, we designed a protocol to allow a breast research biopsy to be collected with informed patient consent concurrent with the diagnostic biopsy at our institution. Here we describe the feasibility of the project. Methods: IRB approval was obtained for the prospective collection and storage of clinically-annotated specimens, including breast biopsy cores, excess surgical tissue from breast surgery, and optional blood collection. Potential participants are identified through the list of scheduled breast biopsies at the Massachusetts General Hospital breast imaging center. Eligible patients are those ≥ age 18 undergoing a clinical breast biopsy. Research consent is obtained in the procedure room immediately following the clinical consent process and prior to the clinical biopsy. Following completion of standard clinical biopsy workflow, two research core biopsy specimens are obtained with a core biopsy needle ranging from 9 to 18 gauge. The first research specimen is flash frozen and stored on dry ice to preserve high molecular weight DNA and RNA. The second sample is cryopreserved in DMSO or a related agent to allow viable cell recovery. All consented patients are entered into a prospective database in REDCap. Medical records of the participating patients are reviewed periodically to collect data on patient demographics, tumor characteristics, and long-term outcomes. Results: From 1/17/19 through 6/28/19, 144 patients were approached. 77.8% of patients consented, resulting in 96 lesions being biopsied for research. Of these, 45.8% were invasive carcinoma, 3.1% were DCIS, 6.1% were high risk lesions, and 44.8% were benign. Among the invasive breast cancers, 78.6% were hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-), 9.5% were HER2+, and 11.9% were triple negative. Conclusion: We demonstrated that an upfront breast research biopsy program in patients presenting for initial diagnostic breast biopsy is feasible, with high rates of patient participation. Overall, 77.8% of approached subjects agreed to a concurrent research breast biopsy at the time of diagnostic biopsy. This approach may provide a high yield mechanism to generate a rich tissue repository with low cost and marginal additional time commitment by patient and providers that can support novel, cross-disciplinary research. A number of collaborative research projects are planned. Citation Format: Kassidy Beyerlin, Christine Edmonds, Siang Boon Koh, Veerle Bossuyt, Annie Ma, Rachel Jimenez, Michelle Specht, Barbara L Smith, Brian Dontchos, Dennis Sgroi, Steven J Isakoff, Constance Lehman, Leif W Ellisen, Laura M Spring. Feasibility of a multidisciplinary diagnostic breast research biopsy project [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-21-01.

Background: In the FAIRLANE trial (NCT02301988) in early TNBC, adding the oral AKT inhibitor IPAT to neoadjuvant PAC led to numerical increases in rates of pathologic complete response (pCR; primary endpoint) and complete response by MRI in unselected patients, with a numerically greater treatment effect in patients with PIK3CA/AKT1/PTEN-altered tumors [Oliveira et al., Ann Oncol 2019]. The IMpassion130 trial established the efficacy of first-line atezolizumab + nab-PAC in patients with PD-L1-positive advanced TNBC [Schmid et al., NEJM 2018]. Preliminary phase 1b results showed promising activity with a triplet combination of IPAT, atezolizumab, and taxane as first-line therapy for advanced TNBC across PIK3CA/AKT1/PTEN and PD-L1 biomarker subgroups [Schmid et al., AACR 2019]. Using samples from the FAIRLANE trial, PD-L1 expression was characterized to evaluate relationships between IPAT treatment effect and expression of PD-L1 and biomarkers relevant to IPAT. Methods: Pretreatment tumor samples were evaluated for genomic alterations using the FoundationOne® assay (Foundation Medicine). Pretreatment PD-L1 status was determined using the SP142 immunohistochemistry assay (VENTANA Medical Systems), with PD-L1 positivity defined as PD-L1 expression on ≥1% of tumor-infiltrating immune cells. Tumor-infiltrating lymphocytes (TILs) were quantified using the Salgado method [Salgado et al., Ann Oncol 2015]. Gene expression was measured by RNA sequencing. Results: Samples were evaluable for genomic alterations in 144 patients, TILs in 135 patients, gene expression in 111 patients, and PD-L1 expression in 99 patients. The prevalence of PD-L1 positivity was 39%, consistent with the reported prevalence in IMpassion130. Compared with PD-L1-negative tumor samples, PD-L1-positive tumor samples showed significantly higher levels of TILs (mean 37% vs 24%; p=0.004) and significantly higher expression of the genes encoding for PD-L1 (CD274: geometric mean 10.5 vs 3.9 counts per million; p Citation Format: Matthew J Wongchenko, Mafalda Oliveira, Cristina Saura, Paolo Nuciforo, Isabel Calvo, Jay Andersen, José L Passos Coelho, Miguel Gil Gil, Begoña Bermejo, Debra A Patt, Eva Ciruelos, Zhen Shi, Na Xu, Patricia Villagrasa, Aruna Mani, Steven J Isakoff. Expression of PD-L1 is independent of PIK3CA/AKT1/PTEN alterations in triple-negative breast cancer (TNBC) and is not associated with response to ipatasertib (IPAT) plus paclitaxel (PAC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-10-23.

Background: eTNBC remains at high risk for recurrence despite modern (neo)adjuvant chemotherapy. Immunotherapy with checkpoint inhibition is active in early and metastatic TNBC, and vaccines may further induce host immune response. PVX-410 (PVX, OncoPep) is a novel tetra-peptide vaccine with 3 of the 4 antigens (XBP1 [2 splice variants] and CD138) commonly overexpressed in TNBC. Here we present results from a phase1b study evaluating safety, tolerability and immune response of PVX and durvalumab (DUR) as adjuvant therapy in eTNBC. Methods: Eligibility for this phase 1b multi-center, single arm study included: HLA-A2+ female patients (pts) with TNBC and tumor size at least 1 cm or node positive; treatment with at least 4 cycles of adjuvant or neoadjuvant chemotherapy; completion of all planned therapy 1-6 months prior to study entry. Pts with local-regional recurrence without evidence of distant metastases treated with curative were also eligible. Pts received 6 doses of 800ug PVX (subcutaneously) emulsified in Montanide and co-administered with Hiltonol (IM) every 2 weeks, and 2 doses of 1500mg DUR (IV) concurrent with the 4th and 6th vaccine treatments. The study included a 6 pt run-in to assess for dose limiting toxicity (DLT), followed by a 14 pt expansion. Blood samples were collected for immune response assessment via flow cytometry at week 0 (Baseline) and at weeks 6, 10, 14, and 24 post-treatment. The primary objective was safety and tolerability. The key secondary objective was PVX specific immune response assessment defined at week 14 as a 2-fold or greater change over baseline in the proportion of CD3+CD8+ T cells that expressed IFNγ and the proportion of CD3+CD8+ T cells positive for PVX tetramers following an in vitro stimulation of PBMC with PVX peptides and a flow cytometric determination. Other immune response assessments included the proportion of CD3+CD8+ T cells expressing TNFα, IL-2, and CD137 following the in vitro peptide stimulation. Results: Among 22 pts enrolled, median age was 48 yrs (range 34-68) and anatomical stage at diagnosis was: Stage 1 = 1 (4.5%), Stage 2 = 14 (64%), and Stage 3 = 7 (32%). Among 20 pts evaluable for week 14 immune response, all planned PVX doses were given, and 1 DUR dose was held due to toxicity (tox). No DLTs were observed in the 6 pt run-in. The most common adverse events (all grades) include: injection site reaction (96%), flu-like symptoms, fatigue (41% each), arthralgia, pruritis (36% each), ALT elevation (32%), myalgia (27%), pain, diarrhea, AST and amylase elevation (23% each). One pt had grade 3 diarrhea and 1 pt had grade 3 hyponatremia, AST and ALT elevation. There were no grade 4 or 5 events. Immune response assessment for the first 12 pts are available at the time of abstract submission. Comparing baseline to week 14, 10 of 12 patients demonstrated a PVX specific immune response (as defined above). Immune response persisted in all patient samples tested at 6 months. Additionally, most pts tested to date had increases over baseline in the proportions of CD3+CD8+ T cells that expressed TNFα, IL-2, and CD137 following the in vitro stimulation with PVX peptides. Final immune response assessment in all 20 evaluable patients will be updated for presentation. At the time of data cut off (4/29/19), with a median follow up of 15.4 months, 4 of 22 (18%) pts had a local (1) or metastatic (3) recurrence and 2 (9%) have died. Conclusions: PVX plus DUR is safe and tolerable in pts with eTNBC with no new unexpected toxicities identified. Immune response data demonstrate that PVX induces antigen-specific T cell expansion and activation in these pts as observed by increases in PVX tetramer, IFNγ, TNFα, IL-2 and CD137 positive T cells. These immune responses to PVX persisted for up to 6 months in most patients, indicating a prolonged immune response. Citation Format: Steven J Isakoff, Sylvia Adams, Hatem H Soliman, Nadine Tung, William T Barry, Jiani Hu, Lorenzo Trippa, Rachel Deering, Joanne Parker, Hannah Park, Elena F Brachtel, Leif W Ellisen, Mariano Severgnini, Doris Peterkin, Sara M Tolaney. A phase 1b study of PVX-410 (PVX) vaccine plus durvalumab (DUR) as adjuvant therapy in HLA-A2+ early stage triple negative breast cancer (eTNBC) to assess safety and immune response [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-09-15.

The role of neoadjuvant therapy (NAT) for localized breast cancer has evolved tremendously over the past several years. Currently, NAT is the preferred option for high-risk early triple-negative (TN) and HER2-positive (HER2+) breast cancers and is indicated for some estrogen receptor–positive (ER+) breast cancers. In addition to traditional absolute indications for NAT, relative indications such as the assessment of outcomes at the time of surgery and guidance of treatment escalation and de-escalation have greatly evolved in recent years. Pathologic complete response (pCR) and the Residual Cancer Burden (RCB) index are highly prognostic for disease recurrence and survival, mainly in patients with TN or HER2+ disease. Furthermore, post-NAT escalation strategies have been shown to improve long-term outcomes of patients who do not achieve pCR. Additionally, by allowing the direct assessment of drug effect on the tumor, the neoadjuvant setting has become an attractive setting for the exploration of novel agents and the identification of predictive biomarkers. Neoadjuvant trial design has also evolved, using adaptive treatment approaches that enable treatment de-escalation or escalation based on response. However, despite multiple practice-changing neoadjuvant trials and the addition of various new agents to the neoadjuvant setting for early breast cancer, many key questions remain. For example, patient selection for neoadjuvant immunotherapy in TN breast cancer, de-escalation methods in HER2+ breast cancer, and the use of gene expression profiles to guide NAT recommendations in ER+ breast cancer. This article reviews the current approach for NAT in localized breast cancer as well as evolving NAT strategies, the key remaining challenges, and the ongoing work in the field.

Background: The ATEMPT trial primary analysis found that one year of adjuvant trastuzumab emtansine (T-DM1) achieved a 3-year iDFS of 97.8% for patients with stage I HER2+ breast cancer, but was not associated with fewer clinically relevant toxicities (CRTs) compared with paclitaxel and trastuzumab (TH). In this end-of-study analysis, we report 5-year survival outcomes and correlative analyses from the trial. Methods: Patients with stage I centrally confirmed HER2+ breast cancer were randomly assigned 3:1 to adjuvant T-DM1 for one year or TH and received T-DM1 3.6 mg/kg IV every 3 weeks for 17 cycles or paclitaxel 80 mg/m2 IV with weekly trastuzumab IV followed by trastuzumab for 9 months. The co-primary objectives were to compare the incidence of CRTs between the 2 arms and to evaluate iDFS in patients receiving T-DM1. To investigate proteomic correlates of recurrence, spatial proteomic analyses were performed on samples from 13 patients experiencing iDFS events (cases) and 24 matched controls using the NanoString GeoMx Digital Spatial Profiler. The impact of HER2 heterogeneity on outcomes was investigated among 17 cases and 51 matched controls by fluorescence in-situ hybridization (FISH). HER2 genetic heterogeneity was assessed by scrutinizing the whole tumor area and defined as the occurrence of HER2 gene amplification in >5% but < 50% invasive tumor cells. The risk of recurrence was evaluated centrally with the HER2DX genomic assay from 225 primary tumor samples. Germline whole genome sequencing (WGS) was conducted among 55 patients experiencing T-DM1-induced thrombocytopenia and/or bleeding and 55 matched controls to identify genomic correlates for this side effect. Results: A total of 497 patients who initiated protocol therapy were included in this analysis (383 T-DM1 and 114 TH). After a median follow up 5.8 years, among patients receiving T-DM1 there were a total of 11 iDFS events, with 3 distant recurrences. The 5-year iDFS for T-DM1 was 97.0% (95% CI, 95.3-98.8%), the 5-year recurrence-free interval (RFI) was 98.6% (95% CI: 97.4-99.8%) and the 5-year overall survival (OS) for T-DM1 was 97.8 % (95% CI, 96.3-99.3%). Although the study was not powered to evaluate the efficacy of TH, among the 114 patients receiving TH, a total of 9 iDFS events were observed, including 2 distant events; the 5-year iDFS with TH was 91.3% (95% CI: 86.0-96.9%), 5-year RFI was 93.3% (95% CI: 88.6-98.2%) and 5-year OS was 97.9% (95% CI: 95.2-100%). A total of 56 samples were evaluable for heterogeneity analyses, among which 14% (n=8) harbored HER2 genetic heterogeneity. Spatial proteomic analyses found that NF1 (adjusted p=0.72 × 10-6) and CTLA-4 (adjusted p=0.15 × 10-3) were significantly upregulated in primary samples from cases, while cleaved caspase 9, CD25, GITR, ICOS, p53 and PD-L2 were significantly upregulated in controls (all with adjusted p< 0.05). Germline WGS found that the top gene associations with thrombocytopenia and thrombocytopenia or bleeding were ALMS1 (p=0,19 × 10-3) and APBA3 (p=0,23 × 10-3), respectively, although none reaching the threshold for genome wide significance. rs62143195 and rs114169776 were the top single nucleotide polymorphisms associated with thrombocytopenia and thrombocytopenia or bleeding, respectively. Data on the impact of HER2 heterogeneity and of HER2DX score on survival outcomes will be presented. Conclusion: With longer follow-up, adjuvant T-DM1 confirmed outstanding long-term outcomes among patients with stage I HER2+ breast cancer, demonstrating a 5-year RFI of 98.6%. Spatial proteomic analyses identified a potential association between NF1 and CTLA-4 expression with recurrence. Details on the impact of HER2 heterogeneity and HER2DX assay on prognosis will be presented. Citation Format: Paolo Tarantino, Nabihah Tayob, Chau T Dang, Denise Yardley, Steven J. Isakoff, Vicente Valero, Meredith Faggen, Therese Mulvey, Ron Bose, Douglas Weckstein, Antonio C. Wolff, Katherine Reeder-Hayes, Hope Rugo, Bhuvaneswari Ramaswamy, Dan Zuckerman, Lowell Hart, Vijayakrishna K. Gadi, Michael Constantine, Kit Cheng, Audrey Merrill Garrett, Paul K. Marcom, Kathy S. Albain, Patricia DeFusco, Nadine Tung, Blair Ardman, Rita Nanda, Rachel C. Jankowitz, Mothaffar Rimawi, Vandana Abramson, Paula R. Pohlmann, Catherine Van Poznak, Andres Forero-Torres, Minetta C. Liu, Kathryn Ruddy, Yue Zheng, Romualdo Barroso-Sousa, Adrienne Waks, Michelle K. DeMeo, Molly K. DiLullo, Giuseppe Curigliano, Harold Burstein, Ann Partridge, Eric Winer, Giuseppe Viale, Winnie Hui, Elizabeth A. Mittendorf, Bryan P. Schneider, Aleix Prat, Ian Krop, Sara Tolaney. Adjuvant Trastuzumab Emtansine Versus Paclitaxel plus Trastuzumab for Stage I HER2+ Breast Cancer: 5-year results and correlative analyses from ATEMPT (TBCRC033) [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 PD18-01.

Background: Serial cell free DNA (cfDNA) analysis in metastatic breast cancer (MBC) is a noninvasive method for tracking tumor evolution and the emergence of new somatic alterations through the course of the disease. The detection of new actionable alterations may impact treatment selection; thus, serial cfDNA collection is increasingly being performed in the clinic. However, it is not well-understood how often serial cfDNA testing identifies new actionable alterations. We evaluated changes in the genomic spectrum of actionable alterations in serial cfDNA analysis of HER2 negative (HER2-) MBC. Method: Patients with HER2- MBC who underwent plasma-based cfDNA testing (Guardant360, 74-gene assay) between February 2015 and February 2021 at an academic institution were included. A retrospective review of records was conducted to identify subtype, demographics, lines of therapy, and cfDNA results. At baseline cfDNA testing, all cfDNA alterations were considered new. For patients with serial draws, new cfDNA alterations in each draw, compared to previous draws, were quantified and characterized. The pathogenicity of new alterations was determined using the OncoKB precision oncology database. New pathogenic alterations were further classified as actionable alterations (AA) using the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT). Alterations that met the ESCAT I (alteration-drug match was associated with improved outcomes in clinical trials) or ESCAT II (alteration-drug match was associated with antitumor activity) criteria were considered as AA. Results: 344 patients with hormone receptor positive (HR+) MBC and 95 patients with triple negative (TN) MBC had a baseline cfDNA draw. Among the HR+ cohort, 139, 79 and 48 patients had 2nd, 3rd, and 4th serial cfDNA draws, respectively. Among the TN cohort, 33 and 18 patients had 2nd and 3rd serial cfDNA draws, respectively. Table 1 depicts the prevalence of AA found in each of these draws, as well as the median number of prior therapies at each point of collection and the mean time between serial draws. The median number of new genomic alterations was lower in subsequent draws compared to the baseline, regardless of subtype (HR+: 4 vs. 2, TN: 4 vs. 1.5-3, at baseline vs. subsequent draws, respectively). In the HR+ cohort the proportion of patients with new AA (ESCAT I/II) decreased from 63% at baseline to 27-33% in the 2nd-4th draws. While some of the new AA in subsequent draws were new actionable variants in the same genes that were known to be altered in previous draws (in 19%, 68% and 57% of patients with new AA in the 2nd, 3rd and 4th draws, respectively), the remainder were new AA in previously unaltered genes. In the TN cohort 25% of patients had new AA at baseline and this proportion of TN patients with new AA continued to decrease in subsequent draws (9% and 0% in the 2nd and 3rd draws, respectively). PIK3CA and ESR1 were the most frequent genes with new AA in the ER+ cohort, regardless of draw number. In the TN cohort, PIK3CA was the most frequent gene with new AA in the first draw, and in the second draw, new AA in PIK3CA, BRCA2, and ERBB2 were present at an equal frequency. Conclusion: While the proportion of patients with HER2- MBC identified to have new AA in serial cfDNA decreased with time for both HR+ and TNBC, new alterations continue to emerge, particularly for patients with HR+ MBC. Further research is needed to determine the impact of serial cfDNA testing on the selection of genotype-matched therapy and outcomes. Table 1. Citation Format: Yael Bar, Jennifer C. Keenan, Lianne Ryan, Dejan Juric, Jennifer Shin, Seth A. Wander, Laura M. Spring, Beverly Moy, Leif Ellisen, Steven J. Isakoff, Aditya Bardia, Neelima Vidula. Changes in the Genomic Spectrum of Actionable Alterations in HER2 Negative Metastatic Breast Cancer in Serial Cell Free DNA (cfDNA) Analysis [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 P4-01-14.

PURPOSE Accurate monitoring of therapeutic response remains an important unmet need for patients with metastatic breast cancer (MBC). Analysis of tumor genomics obtained via circulating tumor DNA (ctDNA) can provide a comprehensive overview of tumor evolution. Here, we evaluated ctDNA change as an early prognostic biomarker of subsequent radiologic progression and survival in MBC. PATIENTS AND METHODS Paired blood samples from patients with MBC were analyzed for levels of ctDNA, carcinoembryonic antigen, and cancer antigen 15-3 at baseline and during treatment. A Clinical Laboratory Improvement Amendments–certified sequencing panel of 73 genes was used to quantify tumor-specific point mutations in ctDNA. Multivariable logistic regression analysis was conducted to evaluate the association between ctDNA rise from baseline to during-treatment (genomic progression) and subsequent radiologic progression and progression-free survival (PFS). RESULTS Somatic mutations were detected in 76 baseline samples (90.5%) and 71 during-treatment samples (84.5%). Patients with genomic progression were more than twice as likely to have subsequent radiologic progression (odds ratio, 2.04; 95% CI, 1.74 to 2.41; P < .0001), with a mean lead time of 5.8 weeks. Genomic assessment provided a high positive predictive value of 81.8% and a negative predictive value of 89.7%. The subset of patients with genomic progression also had shorter PFS (median, 4.2 v 8.3 months; hazard ratio, 2.97; 95% CI, 1.75 to 5.04; log-rank P < .0001) compared with those without genomic progression. CONCLUSION Genomic progression, as assessed by early rise in ctDNA, is an independent biomarker of disease progression before overt radiologic or clinical progression becomes evident in patients with MBC.

Patients with cancer are more likely to have impaired immune responses to SARS-CoV-2 vaccines. We study the breadth of responses against SARS-CoV-2 variants after primary vaccination in 178 patients with a variety of tumor types and after booster doses in a subset. Neutralization of alpha, beta, gamma, and delta SARS-CoV-2 variants is impaired relative to wildtype, regardless of vaccine type. Regardless of viral variant, mRNA1273 is the most immunogenic, followed by BNT162b2, and then Ad26.COV2.S. Neutralization of more variants (breadth) is associated with a greater magnitude of wildtype neutralization, and increases with time since vaccination; advancing age associates with a lower breadth. The concentrations of anti-spike protein antibody are a good surrogate for breadth (positive predictive value of =90% at >1,000 U/mL). Booster SARS-CoV-2 vaccines confer enhanced breadth. These data suggest that achieving a high antibody titer is desirable to achieve broad neutralization; a single booster dose with the current vaccines increases the breadth of responses against variants., Graphical abstract, Naranbhai et al. examine how well current wildtype-based SARS-CoV-2 vaccines perform in patients with cancer in neutralizing viral variants. The findings support preferring the most immunogenic wildtype vaccines (i.e., mRNA1273 or BNT162b2) for patients at high risk to generate breadth against variants.

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.

BackgroundATRC-101 is an engineered version of an immunoglobulin G1 antibody that was discovered in a patient with non-small cell lung cancer (NSCLC) experiencing stable disease while being treated with anti–programmed death-1 therapy. ATRC-101 targets a tumor-specific ribonucleoprotein complex containing polyadenylate binding protein-1, which has been found to be present in the majority of NSCLC, acral melanoma, breast, colorectal, and ovarian cancer samples tested. Target immunoreactivity and single-agent activity have been observed in mouse models. Preclinical data suggest that ATRC-101 stimulates both innate and adaptive immune activity against tumors.MethodsATRC-101-A01 is a phase 1b trial (3+3 dose escalation with expansion cohorts) in patients with solid tumors treated with ATRC-101 monotherapy every 2 or 3 weeks (Q2W or Q3W), or ATRC-101 in combination with pembrolizumab, until unacceptable toxicity or disease progression at doses of 0.3–30 mg/kg, pending dose-limiting toxicities. The primary objective is safety and secondary objectives are to characterize the pharmacokinetic profile, immunogenicity, and anti-tumor activity of ATRC-101, and to determine the recommended dose for expansion. Pharmacodynamic studies will also be performed to evaluate changes from baseline in specific immune cell populations and cytokine levels in blood and tumors. Results from the ATRC-101 0.3–30 mg/kg monotherapy Q3W cohorts are presented in this abstract (data cutoff: July 16, 2021).ResultsTwenty-four participants with solid tumors (13 colorectal, 5 ovarian, 3 breast, 2 NSCLC, 1 acral melanoma) aged 27–75 years with a median 5 lines of prior therapy were treated Q3W in five dose cohorts. No dose-limiting toxicities were observed. Eight participants (33%) experienced grade ≥3 treatment-emergent adverse events. The maximum serum concentration of ATRC-101 and treatment exposure appeared to be dose proportional. Stable disease was observed in eight patients and best response per RECIST v1.1 was associated with expression of the ATRC-101 target. Multiple biomarkers, such as treatment-associated changes in the composition of CD3+, CD4+, and CD8+ T cells in the blood, and serum cytokines/chemokines, including those predicted to activate antigen-presentation pathways, support the proposed mechanism of action of ATRC-101 and will be presented.ConclusionsThese first-in-human data suggest a manageable safety profile for ATRC-101 Q3W, with no dose-limiting toxicities observed. Pharmacokinetics appear to be dose proportional. Enrollment in the Q2W monotherapy dose-escalation cohort and at the 30 mg/kg dose level Q3W is continuing. Trial sites have been activated to test ATRC-101 in combination with pembrolizumab, and combination with chemotherapy is also planned.Trial RegistrationTrial Registration: NCT04244552Ethics ApprovalThis study was approved by the institutional review board or ethics committee as required for each participating site.

Purpose: While chemotherapy remains the standard treatment for triple-negative breast cancer (TNBC), identifying and managing chemoresistant tumors has proven elusive. We sought to discover hallmarks and therapeutically actionable features of refractory TNBC through molecular analysis of primary chemoresistant TNBC specimens. Experimental Design: We performed transcriptional profiling of tumors from a phase II clinical trial of platinum chemotherapy for advanced TNBC (TBCRC-009), revealing a gene expression signature that identified de novo chemorefractory tumors. We then employed pharmacogenomic data mining, proteomic and other molecular studies to define the therapeutic vulnerabilities of these tumors. Results: We reveal the RAS-GTPase-activating protein (RAS-GAP) RASAL2 as an upregulated factor that mediates chemotherapy resistance but also an exquisite collateral sensitivity to combination MAP kinase kinase (MEK1/2) and EGFR inhibitors in TNBC. Mechanistically, RASAL2 GAP activity is required to confer kinase inhibitor sensitivity, as RASAL2-high TNBCs sustain basal RAS activity through suppression of negative feedback regulators SPRY1/2, together with EGFR upregulation. Consequently, RASAL2 expression results in failed feedback compensation upon co-inhibition of MEK1/2 and EGFR that induces synergistic apoptosis in vitro and in vivo. In patients with TNBC, high RASAL2 levels predict clinical chemotherapy response and long-term outcomes, and are associated via direct transcriptional regulation with activated oncogenic Yes-Associated Protein (YAP). Accordingly, chemorefractory patient-derived TNBC models exhibit YAP activation, high RASAL2 expression, and tumor regression in response to MEK/EGFR inhibitor combinations despite well-tolerated intermittent dosing. Conclusions: These findings identify RASAL2 as a mediator of TNBC chemoresistance that rewires MAPK feedback and cross-talk to confer profound collateral sensitivity to combination MEK1/2 and EGFR inhibitors.

PURPOSE To evaluate the safety and efficacy of proton beam radiation therapy (RT) for patients with breast cancer who require regional nodal irradiation. METHODS Patients with nonmetastatic breast cancer who required postoperative RT to the breast/chest wall and regional lymphatics and who were considered suboptimal candidates for conventional RT were eligible. The primary end point was the incidence of grade 3 or higher radiation pneumonitis (RP) or any grade 4 toxicity within 3 months of RT. Secondary end points were 5-year locoregional failure, overall survival, and acute and late toxicities per Common Terminology Criteria for Adverse Events (version 4.0). Strain echocardiography and cardiac biomarkers were obtained before and after RT to assess early cardiac changes. RESULTS Seventy patients completed RT between 2011 and 2016. Median follow-up was 55 months (range, 17 to 82 months). Of 69 evaluable patients, median age was 45 years (range, 24 to 70 years). Sixty-three patients (91%) had left-sided breast cancer, two had bilateral breast cancer, and five had right-sided breast cancer. Sixty-five (94%) had stage II to III breast cancer. Sixty-eight (99%) received systemic chemotherapy. Fifty (72%) underwent immediate reconstruction. Median dose to the chest wall/breast was 49.7 Gy (relative biological effectiveness) and to the internal mammary nodes, 48.8 Gy (relative biological effectiveness), which indicates comprehensive coverage. Among 62 surviving patients, the 5-year rates for locoregional failure and overall survival were 1.5% and 91%, respectively. One patient developed grade 2 RP, and none developed grade 3 RP. No grade 4 toxicities occurred. The unplanned surgical re-intervention rate at 5 years was 33%. No significant changes in echocardiography or cardiac biomarkers after RT were found. CONCLUSION Proton beam RT for breast cancer has low toxicity rates and similar rates of disease control compared with historical data of conventional RT. No early cardiac changes were observed, which paves the way for randomized studies to compare proton beam RT with standard RT.

Plasma genotyping identifies potentially actionable mutations at variable mutant allele frequencies, often admixed with multiple subclonal variants, highlighting the need for their clinical and functional validation. We prospectively monitored plasma genotypes in 143 women with endocrine-resistant metastatic breast cancer (MBC), identifying multiple novel mutations including HER2 mutations (8.4%), albeit at different frequencies highlighting clinical heterogeneity. To evaluate functional significance, we established ex vivo culture from circulating tumor cells (CTCs) from a patient with HER2-mutant MBC, which revealed resistance to multiple targeted therapies including endocrine and CDK 4/6 inhibitors, but high sensitivity to neratinib (IC50: 0.018 μM). Immunoblotting analysis of the HER2-mutant CTC culture line revealed high levels of HER2 expression at baseline were suppressed by neratinib, which also abrogated downstream signaling, highlighting oncogenic dependency with HER2 mutation. Furthermore, treatment of an index patient with HER2-mutant MBC with the irreversible HER2 inhibitor neratinib resulted in significant clinical response, with complete molecular resolution of two distinct clonal HER2 mutations, with persistence of other passenger subclones, confirming HER2 alteration as a driver mutation. Thus, driver HER2 mutant alleles that emerge during blood-based monitoring of endocrine-resistant MBC confer novel therapeutic vulnerability, and ex vivo expansion of viable CTCs from the blood circulation may broadly complement plasma-based mutational analysis in MBC.

Background As scientific techniques evolve, historical informed consent forms may inadequately address modern research proposals, leading to ethical questions regarding research with archived biospecimens. Subjects, Materials, and Methods We conducted focus groups among patients with cancer recruited from Massachusetts General Hospital to explore views on medical research, biobanking, and scenarios based on real biospecimen research dilemmas. Our multidisciplinary team developed a structured focus group guide, and all groups were recorded and transcribed. Transcripts were coded for themes by two independent investigators using NVivo software. Results Across five focus groups with 21 participants, we found that most participants were supportive of biobanks and use of their own tissue to advance scientific knowledge. Many favor allowing research beyond the scope of the original consent to proceed if recontact is impossible. However, participants were not comfortable speaking for other patients who may oppose research beyond the original consent. This was viewed as a potential violation of participants’ rights or interests. Participants were also concerned with a “slippery slope” and potential scientific abuse if research were permitted without adherence to original consent. There was strong support for recontact and reconsent when possible and for the concept of broad consent at the time of tissue collection. Conclusion Our participants support use of their tissue to advance research and generally support any productive scientific approach. However, in the absence of broad initial consent, when recontact is impossible, a case-by-case decision must be made regarding a proposal's potential benefits and harms. Many participants support broad use of their tissue, but a substantial minority object to use beyond the original consent. Implications for Practice For prospective studies collecting tissue for future research, investigators should consider seeking broad consent, to allow for evolution of research questions and methods. For studies using previously collected tissues, researchers should attempt recontact and reconsent for research aims or methods beyond the scope of the original consent. When reconsent is not possible, a case-by-case decision must be made, weighing the scientific value of the biobank, potential benefits of the proposed research, and the likelihood and nature of risks to participants and their welfare interests. This study's data suggest that many participants support broad use of their tissue and prefer science to move forward.

This study evaluated development of edema in patients receiving PI3K/mTOR/CDK4/6 targeted therapy for metastatic breast cancer (MBC). We reviewed medical records of 160 patients receiving targeted therapy with PI3K/mTOR/CDK4/6 inhibitors to treat MBC (n = 160; 185 treatment occurrences). Clinicopathologic data, treatment details, and edema incidence were recorded. Edema incidence was 43.1% (69/160) overall and 25.6% (41/160) in the upper extremity ipsilateral to the treated breast. In 185 therapy regimens administered, 6.8% of patients on a PI3K inhibitor, 8.8% of patients on an mTOR inhibitor, and 9.2% of patients on a CDK4/6 inhibitor experienced new onset or worsened preexisting upper extremity edema. Further, 9.1% of patients on a PI3K inhibitor, 18.8% of patients on an mTOR inhibitor, and 10.5% of patients on a CDK4/6 inhibitor experienced new onset or worsened preexisting edema elsewhere in the body. Multivariate logistic regression showed that, beyond the established breast cancer-related lymphedema (BCRL) risk factors [axillary lymph node dissection (Odds Ratio (OR) 2.69, p = 0.020), regional lymph node irradiation (OR 6.47, p

Standard chemotherapy is associated with low response rates and short progression-free survival among patients with pretreated metastatic triple-negative breast cancer. Sacituzumab govitecan-hziy is an antibody-drug conjugate that combines a humanized monoclonal antibody, which targets the human trophoblast cell-surface antigen 2 (Trop-2), with SN-38, which is conjugated to the antibody by a cleavable linker. Sacituzumab govitecan-hziy enables delivery of high concentrations of SN-38 to tumors.We conducted a phase 1/2 single-group, multicenter trial involving patients with advanced epithelial cancers who received sacituzumab govitecan-hziy intravenously on days 1 and 8 of each 21-day cycle until disease progression or unacceptable toxic effects. A total of 108 patients received sacituzumab govitecan-hziy at a dose of 10 mg per kilogram of body weight after receiving at least two previous anticancer therapies for metastatic triple-negative breast cancer. The end points included safety; the objective response rate (according to Response Evaluation Criteria in Solid Tumors, version 1.1), which was assessed locally; the duration of response; the clinical benefit rate (defined as a complete or partial response or stable disease for at least 6 months); progression-free survival; and overall survival. Post hoc analyses determined the response rate and duration, which were assessed by blinded independent central review.The 108 patients with triple-negative breast cancer had received a median of 3 previous therapies (range, 2 to 10). Four deaths occurred during treatment; 3 patients (2.8%) discontinued treatment because of adverse events. Grade 3 or 4 adverse events (in ≥10% of the patients) included anemia and neutropenia; 10 patients (9.3%) had febrile neutropenia. The response rate (3 complete and 33 partial responses) was 33.3% (95% confidence interval [CI], 24.6 to 43.1), and the median duration of response was 7.7 months (95% CI, 4.9 to 10.8); as assessed by independent central review, these values were 34.3% and 9.1 months, respectively. The clinical benefit rate was 45.4%. Median progression-free survival was 5.5 months (95% CI, 4.1 to 6.3), and overall survival was 13.0 months (95% CI, 11.2 to 13.7).Sacituzumab govitecan-hziy was associated with durable objective responses in patients with heavily pretreated metastatic triple-negative breast cancer. Myelotoxic effects were the main adverse reactions. (Funded by Immunomedics; IMMU-132-01 ClinicalTrials.gov number, NCT01631552.).

These NCCN Guidelines Insights highlight the updated recommendations for use of multigene assays to guide decisions on adjuvant systemic chemotherapy therapy for women with hormone receptor–positive, HER2-negative early-stage invasive breast cancer. This report summarizes these updates and discusses the rationale behind them.

Purpose: Despite extensive genomic and transcriptomic profiling, it remains unknown how signaling pathways are differentially activated and how tumors are differentially sensitized to certain perturbations. Here, we aim to characterize AKT signaling activity and its association with other genomic or IHC-based PI3K/AKT pathway biomarkers as well as the clinical activity of ipatasertib (AKT inhibitor) in the FAIRLANE trial. Experimental Design: In FAIRLANE, 151 patients with early triple-negative breast cancer (TNBC) were randomized 1:1 to receive paclitaxel with ipatasertib or placebo for 12 weeks prior to surgery. Adding ipatasertib did not increase pathologic complete response rate and numerically improved overall response rate by MRI. We used reverse-phase protein microarrays (RPPA) to examine the total level and/or phosphorylation states of over 100 proteins in various signaling or cell processes including PI3K/AKT and mTOR signaling. One hundred and twenty-five baseline and 127 on-treatment samples were evaluable by RPPA, with 110 paired samples at both time points. Results: Tumors with genomic/protein alterations in PIK3CA/AKT1/PTEN were associated with higher levels of AKT phosphorylation. In addition, phosphorylated AKT (pAKT) levels exhibited a significant association with enriched clinical benefit of ipatasertib, and identified patients who received benefit in the absence of PIK3CA/AKT1/PTEN alterations. Ipatasertib treatment led to a downregulation of AKT/mTORC1 signaling, which was more pronounced among the tumors with PIK3CA/AKT1/PTEN alterations or among the responders to the treatment. Conclusions: We showed that the high baseline pAKT levels are associated with the alterations of PI3K/AKT pathway components and enriched benefit of ipatasertib in TNBC.

This single-arm pilot study (NCT03329937) evaluated neoadjuvant niraparib antitumor activity and safety in patients with localized HER2-negative, BRCA-mutated breast cancer. Twenty-one patients received niraparib 200 mg once daily in 28-day cycles. After 2 cycles, tumor response (≥30% reduction from baseline) by MRI was 90.5% and 40.0% (6 of 15) of patients who received only niraparib (2-6 cycles) had pathological complete response; no new safety signals were identified. High niraparib intratumoral concentration was observed.

PURPOSE Human epidermal growth factor receptor 2 (HER2)–directed treatments improve outcomes for patients with HER2-positive metastatic breast cancer (MBC). Current identification of patients with HER2-positive disease relies on tumor tissue testing, which can be inaccurate because of tumor heterogeneity or tumor evolution. Circulating tumor cells (CTCs) are often present in patients with cancer. We hypothesized that HER2 assessment of CTCs in patients with HER2-negative breast cancer could identify a subset of patients with HER2-positive CTCs who could benefit from HER2-directed treatments. METHODS This was a single-arm, two-stage, phase II trial. Patients with HER2-negative progressive MBC with HER2-positive CTC (defined as HER2/CEP17 ratio ≥ 2.0 by fluorescence in situ hybridization), ≥ 1 prior chemotherapy regimen for MBC, and no prior vinorelbine received trastuzumab in combination with vinorelbine on days 1, 8, and 15 of a 21-day cycle. The primary end point was objective response rate. RESULTS From January 2013 to June 2014, we prospectively screened CTCs from patients with HER2-negative MBC. CTCs were detected in 201 of 311 patients (65%). The median number of CTCs was 10 (interquartile range, 3-57). Sixty-nine of 311 patients (22%) had HER2+ CTCs, with a median of three HER2+ CTCs (range 1-21). Twenty patients with HER2+ CTCs were treated on study. At data cutoff (January 13, 2017), no patients remained on study therapy. The objective response rate was 5% (95% CI, 0.1 to 24.9), with one of 20 patients experiencing a partial response. The clinical benefit rate was 20.0% (1 partial response and 3 stable diseases > 24 weeks, 95% CI, 5.7% to 43.7%). The median progression-free survival was 2.7 months. CONCLUSION CTC analysis of patients with HER2-negative MBC identifies a subset with HER2-amplified CTCs. However, clinical activity of an HER2-directed regimen in this population was low. The functional significance of HER2-positive CTCs remains uncertain.

Chemotherapy-related amenorrhea (CRA) is a surrogate for ovarian toxicity and associated risk of infertility and premature menopause. Here, we compare CRA rate with paclitaxel (T)-trastuzumab (H) to that with ado-trastuzumab emtansine (T-DM1). Patients with T1N0 HER2 + early-stage breast cancer (eBC) enrolled on the ATEMPT trial and were randomized 3:1 to T-DM1 3.6 mg/kg IV every (q) 3 weeks (w) × 17 vs. T 80 mg/m2 with H IV qw × 12 (4 mg/kg load → 2 mg/kg), followed by H (6 mg/kg IV q3w × 13). Enrollees who self-reported as premenopausal were asked to complete menstrual surveys at baseline and every 6–12 months for 60 months. 18-month CRA (no periods reported during prior 6 months on 18-month survey) was the primary endpoint of this analysis. Of 512 ATEMPT enrollees, 123 who began protocol therapy and answered baseline and at least one follow-up menstrual survey were premenopausal at enrollment. 76 had menstrual data available at 18 months without having received a gonadotropin-releasing hormone agonist or undergone hysterectomy and/or oophorectomy. Median age was 45 (range 23–53) among 18 who had received TH and 46 (range 34–54) among 58 who had received T-DM1. The 18-month rate of CRA was 50% after TH and 24% after T-DM1 (p = 0.045). Amenorrhea at 18 months was less likely in recipients of adjuvant T-DM1 than TH. Future studies are needed to understand how T-DM1 impacts risk of infertility and permanent menopause, and to assess amenorrhea rates when T-DM1 is administered after standard HER2-directed chemotherapy regimens.

There are limited data on trastuzumab-pertuzumab (HP)-based treatments beyond the first-line, HER2+ metastatic breast cancer (MBC) setting. We conducted a phase II study of eribulin mesylate, which extends survival in MBC, with HP in patients with previously treated HER2+ MBC to evaluate efficacy, toxicity, and genomic alterations driving therapeutic response.After a run-in phase for eribulin dosing, two cohorts were enrolled (Cohort A-no prior pertuzumab; Cohort B-prior pertuzumab). All patients received eribulin 1.4 mg/mThe six-patient run-in established a dose of eribulin 1.4 mg/mEribulin-HP had manageable toxicity and modest clinical activity in patients without prior pertuzumab exposure. This study provides a preliminary landscape of somatic alterations in this patient cohort. Our data add to the literature on how genomic alterations may predict for therapy response/resistance, as we work to individualize choices in a quickly evolving HER2+ MBC treatment landscape.www.clinicaltrials.gov , NCT01912963. Registered 24 July 2013.

e13592 Background: NLP (artificial intelligence) can automate the identification of records in large datasets. The purpose of this study was to evaluate the feasibility of NLP to identify breast cancer-associated lung metastases to understand clinical characteristics and challenges posed by this common site of breast cancer recurrence. Methods: Patients with pathologically confirmed breast cancer associated-lung metastases seen at a large academic center between 3/2012-5/2019 were identified using NLP of institutional pathology reports, with an IRB approved protocol. Chart review was performed to confirm breast cancer associated-lung metastases and determine clinical and pathological features. Results: Using NLP, 32 patients with pathology reports denoting breast cancer associated-lung metastases were identified, with pathologic confirmation of lung biopsy tissue in the majority of cases (24), and pleural fluid specimens (8) on the remainder. Ten of 32 (31%) were HR+/HER2-, 3/32 (9.3%) HER2+, and 19/32 (59%) TNBC. The majority were invasive ductal carcinoma (21/26) with the remainder invasive lobular carcinoma (2/26) or mixed histology (3/26). Median age at lung metastasis diagnosis was 62 years (range 31-88). The median time to development of lung metastasis following primary breast cancer was 5.6 years (range 0-24.8 years). Fifty six percent of lung metastases were detected on imaging and 44% by symptoms including dyspnea, cough, or pain. Tumor tissue genotyping results on the lung metastases were available for 8 patients showing PI3KCA (5), TP53 (3), SMARCA4 (2), ERBB2 (1), FGFR3 (1), ATM (1), CDK4 (1), MYC (1), and ESR1 (1). Treatment after diagnosis of lung metastases included hormone therapy (61%), chemotherapy (84%), lung irradiation (26%), and surgical resection of lung metastases (6%). Lung metastases were associated with considerable morbidity including pleural effusion (15%), dyspnea (6%), pneumothorax (3%), hemothorax (3%), and atelectasis (3%). Patients diagnosed with lung metastases had brain (32%), bone (35%), renal (6%), skin (3%) and adrenal (3%) metastases during disease course. Conclusions: NLP can help identify organ specific metastases from pathology reports, such as breast cancer associated-lung metastases, which can then facilitate observational, translational, and clinical research to characterize and address challenges posed by this common site of breast cancer recurrence. This cohort of patients highlights the morbidity of breast cancer associated-lung metastases and potential role of NLP for disease characterization and clinical research. (Support from ASCO Medical Student Rotation for Underrepresented Populations Award.)

e12521 Background: The anti-HER2 antibody trastuzumab has vastly improved outcomes for women with early stage and advanced HER2+ breast cancer (BC) when used in combination with chemotherapy. Anthracycline and taxane-based regimens have historically made up the chemotherapy backbone for patients with localized HER2+ BC, though recent evidence suggests anthracyclines can be safely omitted. The single arm phase II APT trial established trastuzumab and paclitaxel as the standard adjuvant regimen for small HER2+ tumors. However, paclitaxel requires weekly treatment, causes alopecia, and has high rates of neuropathy and hypersensitivity reactions. In patients with metastatic HER2+ BC, the combination of trastuzumab and vinorelbine (TV) is effective and well tolerated. There is a need for alternative regimens for patients with HER2+ early-stage BC, especially for those with contraindications to anthracycline and taxane-based regimens. We conducted a retrospective study of patients with early stage HER2+ BC treated with adjuvant TV to evaluate a non-anthracycline/taxane-based, alopecia-sparing regimen. Methods: Clinicopathological characteristics, treatment details, and outcomes of patients with localized HER2+ BC treated with adjuvant TV for from 2007 to 2021 at a large academic medical institution were collected. Study endpoints included invasive disease-free survival (IDFS), overall survival (OS), and safety/tolerability. IDFS and OS were measured from start date of TV treatment to date of event or last follow-up, respectively. 5-year survival rates were generated in GraphPad Prism. Results: A total of 25 patients were treated with TV. All patients received trastuzumab at standard dosing and vinorelbine at a starting dose of 25 mg/m2 on days 1/8 of a 21-day cycle with 4 planned cycles. Median age at diagnosis was 61 years (range: 36-81). 88% of patients had anatomic pathologic Stage IA BC and 12% Stage IIA BC. Of the 25 patients, 24 of them opted to pursue TV due to concerns over alopecia, neuropathy, and other toxicities while 1 patient had received prior adriamycin and therefore opted for TV. With a median follow-up time of 68 months (5.7 years), the 5-year rate of survival from invasive disease was 90.9%, with 1 local and 1 distant recurrence. The 5-year overall survival was 100%. 76% of patients completed 4 cycles of TV without dose holds or delays and 92% completed 4 cycles without dose reductions. 2 patients required hospitalization during treatment with TV due to toxicity (diarrhea attributed to V, rigors/fever attributed to T). No patients experienced alopecia or long-term neuropathy. Conclusions: Trastuzumab in combination with vinorelbine in the adjuvant, early-stage setting for HER2+ BC is effective and well-tolerated and warrants further exploration as an alternative to taxane-based regimen.

512 Background: Sacituzumab govitecan (SG), a novel antibody-drug conjugate in which the topoisomerase 1 inhibitor SN-38 (active metabolite of irinotecan) is linked to a humanized monoclonal antibody targeting the tumor antigen Trop2, is currently approved for treatment of patients (pts) with pre-treated metastatic triple negative breast cancer (TNBC). We conducted a phase 2 study evaluating neoadjuvant (NA) SG as upfront therapy for pts with localized TNBC (NCT04230109). The primary objective was to assess pathological complete response (pCR) rate in breast and lymph nodes (ypT0/isN0) with SG. Secondary objectives included assessment of radiological response rate, evaluation of the safety and tolerability (CTCAE v5.0) and event-free survival (EFS). Methods: Patients with localized TNBC (tumor size ≥1cm, or any size if node positive) with no prior treatment were eligible. SG was administered IV on Days 1, 8 of each 21-day cycle at a starting dose of 10 mg/kg for 4 cycles. After 4 cycles, patients with biopsy-proven residual disease, considered as no pCR for primary endpoint, had the option to receive additional NA therapy at the discretion of the treating physician. Radiologic response (US or MRI) was defined by RECIST version 1.1 using a composite response of CR & PR. Standard descriptive statistics were utilized, including 95% binomial confidence intervals for all rates estimated. Results: From 7/14/20 – 8/31/21, 50 pts were enrolled (median age = 48.5; 11 stage I disease, 24 stage II, 11 stage III, 4 unknown; 62% node negative). The majority (98%; n = 49) of pts completed 4 cycles of SG. Overall, the radiological response rate with SG alone was 62% (n = 31, 95% CI 48%, 77%). 26 pts proceeded directly to surgery after SG. Overall, the pCR rate with SG alone was 30% (n = 15/50, 95% CI 18%, 45%). The other 11 pts had RCB-1 (n = 3), RCB-2 (n = 5), and RCB-3 (n = 3) disease, respectively. Of the 24 pts who received additional NA therapy, 6 had a pCR (3 received anthracycline-based regimen, 2 carboplatin/taxane, and 1 docetaxel/cyclophosphamide). Among pts with a germline BRCA mutation (n = 8), 7 proceeded directly to surgery after SG and 6 had a pCR (86%, 95% CI 42%, 99%). The most common AEs with SG were nausea (82%, n = 41), fatigue (78%, n = 39), alopecia (76%, n = 38), neutropenia (58%, n = 29), anemia (36%, n = 18), and rash (48%, n = 24). 6% of pts required dose-reduction. No pts discontinued SG therapy due to disease progression or AEs; 1 discontinued due to minimal response per investigator preference. At the time of data cut-off (1/18/22), no pts experienced disease recurrence. Updated biomarker and EFS results will be presented at the meeting. Conclusions: In the first neoadjuvant trial in TNBC with an ADC, SG demonstrated single agent efficacy in localized TNBC. Further research on optimal duration of SG as well as NA combination strategies, including immunotherapy, are needed. Clinical trial information: NCT04230109.

e24119 Background: The need for improvement in education and decision-making support for patients with breast cancer is well documented. Digital health applications offer potential to address these needs through widely available smartphone technology. Understanding patients’ baseline preferences for information sources, breast cancer-related topics of interest, and current use of smartphones and how these interests may differ based on demographic and clinical factors can inform the development of a patient-centered digital navigation tool. Methods: As part of a pilot trial of the Outcomes4Me breast cancer navigation app, we conducted a baseline cross-sectional survey of patients presenting for routine breast cancer care at an academic medical center and community-based sites. Eligible patients had invasive breast cancer of any stage and were actively in treatment. Survey-specific questions addressed sources of cancer information and informational needs. Analysis is descriptive with statistical comparisons based on Fisher’s exact test. Results: Ninety out of 107 patients in the pilot trial completed the survey items of interest. The majority of patients were over age 50 (59%) and 35% had stage IV disease. Baseline reported uses for mobile devices included text (67%), email (61%), phone (47%), social media (41%), accessing the internet (18%), and apps (12%). Only 7% of patients noted using mobile apps for navigating disease and treatment options. When asked to rank the importance of cancer information sources, 88% and 42% of patients reported relying heavily on their oncologist and the rest of the care team, respectively. Forty percent of patients relied at least moderately on the internet for health information and 27% on online support groups, with patients < age 50 more likely than those > age 50 to rely on online support groups for health information (41% vs 17%, P = 0.02). The most common educational needs reported were side effects (79%), followed by prognosis (72%), healthy lifestyle (71%), treatment options (70%), general breast cancer news and research (67%), information about their current cancer status (59%), potential clinical trials (44%), and costs of treatment (14%). Patients with metastatic breast expressed greater interest in information about clinical trials compared to those without metastatic disease (64% vs 36%, P = 0.01), and less interest in information about prognosis (54% vs. 81%, P = 0.01). Conclusions: Despite reliance on their oncologist and oncology team for information, patients report multiple unmet educational needs related to their disease and treatment options. While a substantial percentage of patients with breast cancer turn to the internet for information, there is untapped potential to use mobile devices to improve patient education and awareness of treatment options, including clinical trials.

Introduction The CREATE-X study, conducted in Japan and South Korea, established capecitabine as an adjuvant treatment option for patients with triple negative breast cancer (TNBC) who have residual disease (RD) following neoadjuvant anthracycline or taxane-based chemotherapy. However, there are no reports on the tolerability and outcomes of adjuvant capecitabine in the US setting following publication of the CREATE-X data. Methods We retrospectively collected treatment and tolerability data from the medical records of the first 23 TNBC patients who received adjuvant capecitabine for RD post neoadjuvant chemotherapy at our institution. Disease-free survival was assessed using the Kaplan-Meier method. Results The median starting dosage of capecitabine was 1871 mg/m2/day, most commonly divided into two daily doses on days 1-14 of each 21 day cycle. 34.8% of patients completed the treatment as prescribed. Side effects associated with treatment were common with 69.6% of patients experiencing hand-foot syndrome, 39.1% of patients experiencing diarrhea, and 13.0% of patients requiring hospitalization for side effects. Of 23 patients treated with adjuvant capecitabine, 34.8% completed the planned dose, 30.4% completed with dose reduction, and 34.8% discontinued early. At a median follow-up time of 14 months, the median disease-free survival was 22 months, with 30.4% of patients experiencing recurrence. Conclusion Tolerability was poor overall compared to the CREATE-X cohort. Administering adjuvant capecitabine for TNBC patients with residual disease in the United States is challenging given differences in tolerability. More research is needed to understand how poor tolerability will affect the efficacy of this approach in the US population.

Purpose: Actionable mutations can guide genotype-directed matched therapy. We evaluated the utility of tissue-based and plasma-based genotyping for the identification of actionable mutations and selection of matched therapy in patients with metastatic breast cancer (MBC). Experimental Design: Patients with MBC who underwent tissue genotyping (institutional platform, 91-gene assay) or plasma-based cell-free DNA (cfDNA, Guardant360, 73-gene assay) between January 2016 and December 2017 were included. A chart review of records to identify subtype, demographics, treatment, outcomes, and tissue genotyping or cfDNA results was performed. The incidence of actionable mutations and the selection of matched therapy in tissue genotyping or cfDNA cohorts was determined. The impact of matched therapy status on overall survival (OS) in tissue genotyping or cfDNA subgroups was determined with Cox regression analysis. Results: Of 252 patients who underwent cfDNA testing, 232 (92%) had detectable mutations, 196 (78%) had actionable mutations, and 86 (34%) received matched therapy. Of 118 patients who underwent tissue genotyping, 90 (76%) had detectable mutations, 59 (50%) had actionable mutations, and 13 (11%) received matched therapy. For cfDNA patients with actionable mutations, matched versus nonmatched therapy was associated with better OS [HR 0.41, 95% confidence interval (CI): 0.23–0.73, P = 0.002], and this remained significant in a multivariable analysis correcting for age, subtype, visceral metastases, and brain metastases (HR = 0.46, 95% CI: 0.26–0.83, P = 0.010). Conclusions: Plasma-based genotyping identified high rates of actionable mutations, which was associated with significant application of matched therapy and better OS in patients with MBC. See related commentary by Rugo and Huppert, p. 3275

Background: Inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6i) are widely used as first-line therapy for hormone receptor–positive metastatic breast cancer (HR+ MBC). Although abemaciclib monotherapy is also FDA-approved for treatment of disease progression on endocrine therapy, there is limited insight into the clinical activity of abemaciclib after progression on prior CDK4/6i. Patients and Methods: We identified patients with HR+ MBC from 6 cancer centers in the United States who received abemaciclib after disease progression on prior CDK4/6i, and abstracted clinical features, outcomes, toxicity, and predictive biomarkers. Results: In the multicenter cohort, abemaciclib was well tolerated after a prior course of CDK4/6i (palbociclib)-based therapy; a minority of patients discontinued abemaciclib because of toxicity without progression (9.2%). After progression on palbociclib, most patients (71.3%) received nonsequential therapy with abemaciclib (with ≥1 intervening non-CDK4/6i regimens), with most receiving abemaciclib with an antiestrogen agent (fulvestrant, 47.1%; aromatase inhibitor, 27.6%), and the remainder receiving abemaciclib monotherapy (19.5%). Median progression-free survival for abemaciclib in this population was 5.3 months and median overall survival was 17.2 months, notably similar to results obtained in the MONARCH-1 study of abemaciclib monotherapy in heavily pretreated HR+/HER2-negative CDK4/6i-naïve patients. A total of 36.8% of patients received abemaciclib for ≥6 months. There was no relationship between the duration of clinical benefit while on palbociclib and the subsequent duration of treatment with abemaciclib. RB1, ERBB2, and CCNE1 alterations were noted among patients with rapid progression on abemaciclib. Conclusions: A subset of patients with HR+ MBC continue to derive clinical benefit from abemaciclib after progression on prior palbociclib. These results highlight the need for future studies to confirm molecular predictors of cross-resistance to CDK4/6i therapy and to better characterize the utility of abemaciclib after disease progression on prior CDK4/6i.

The COVID-19 pandemic presents clinicians a unique set of challenges in managing breast cancer (BC) patients. As hospital resources and staff become more limited during the COVID-19 pandemic, it becomes critically important to define which BC patients require more urgent care and which patients can wait for treatment until the pandemic is over. In this Special Communication, we use expert opinion of representatives from multiple cancer care organizations to categorize BC patients into priority levels (A, B, C) for urgency of care across all specialties. Additionally, we provide treatment recommendations for each of these patient scenarios. Priority A patients have conditions that are immediately life threatening or symptomatic requiring urgent treatment. Priority B patients have conditions that do not require immediate treatment but should start treatment before the pandemic is over. Priority C patients have conditions that can be safely deferred until the pandemic is over. The implementation of these recommendations for patient triage, which are based on the highest level available evidence, must be adapted to current availability of hospital resources and severity of the COVID-19 pandemic in each region of the country. Additionally, the risk of disease progression and worse outcomes for patients need to be weighed against the risk of patient and staff exposure to SARS CoV-2 (virus associated with the COVID-19 pandemic). Physicians should use these recommendations to prioritize care for their BC patients and adapt treatment recommendations to the local context at their hospital.

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Bladder Cancer focuses on the clinical presentation and workup of suspected bladder cancer, treatment of non-muscle-invasive urothelial bladder cancer, and treatment of metastatic urothelial bladder cancer because important updates have recently been made to these sections. Some important updates include recommendations for optimal treatment of non-muscle-invasive bladder cancer in the event of a bacillus Calmette-Guerin (BCG) shortage and details about biomarker testing for advanced or metastatic disease. The systemic therapy recommendations for second-line or subsequent therapies have also been revised. Treatment and management of muscle-invasive, nonmetastatic disease is covered in the complete version of the NCCN Guidelines for Bladder Cancer available at NCCN.org. Additional topics covered in the complete version include treatment of nonurothelial histologies and recommendations for nonbladder urinary tract cancers such as upper tract urothelial carcinoma, urothelial carcinoma of the prostate, and primary carcinoma of the urethra.