Early Triple-negative Breast Cancer Research Articles

Abstract PS18-04: Prospective evaluation of patients with metaplastic (Mp) triple negative breast cancer (TNBC): Molecular characteristics and outcomes with neoadjuvant therapy (NAT)

Abstract Background: MpBC is a rare breast cancer subtype that is commonly triple-negative and associated with a diminished response to NAT in published retrospective data sets, prompting some clinicians to recommend surgical resection followed by adjuvant therapy. Methods: The ARTEMIS trial (NCT02276443) uses imaging response and molecular profiling to personalize NAT in early stage TNBC. Patients with sensitive disease after 4 cycles of AC receive standard taxane-based NAT as the second phase of NAT, while those with resistant disease are offered biomarker-guided therapeutic trials. Pathologic response is assessed at surgical resection. Prospective data from 195 patients with early-stage TNBC (MpTNBC: N=37; Non-MpTNBC: N=158) enrolled on the ARTEMIS trial were evaluated. Due to short duration of follow-up, restricted mean survival time up to four years of follow-up was used to evaluate event-free survival (RM-EFS), metastasis-free survival (RM-MFS) and overall survival (RM-OS). RNAseq and whole exome sequencing (WES) were performed on pre-NAT core biopsies (155 and 158 non-MpTNBC respectively; 20 MpTNBC). Stromal tumor infiltrating lymphocytes (sTIL) and PD-L1 staining were also compared. Results: Pathologic complete response (pCR) rates were significantly lower in MpTNBC vs non-MpTNBC (18.9% vs. 41.4%, p=0.013). Among MpTNBC without pCR (n=30, 81%), 21 were detected early to have progression (PD) or suboptimal response to standard therapy with ultrasound and clinical exam and were offered the opportunity to participate in clinical trial. Notably, 6 patients (16.2%) had PD after 2 cycles of AC. There was a non-statistically significant trend of lower RM-EFS, RM-MFS, and RM-OS in MpTNBC; however, MpTNBCs with pCR had similar RM-OS compared to non-MpTNBCs with pCR. MpTNBCs had lower rates of high TIL (>20%) compared to non-MpTNBCs (16% vs. 36%, p=0.02) but similar rates of PD-L1+ disease. Compared to non-MpTNBCs, using Vanderbilt classification methods, MpTNBCs were more frequently M/MSL subtype (50% vs 22%, p=0.011) and less frequently BL-1 subtype (p=0.028). By RNAseq, MpTNBC tumors had significantly lower gene expression of epithelial markers CDH1, EPCAM, ESRP1, and increased expression of EMT inducer TWIST1. WES identified PIK3CA missense mutations in 15% of MpTNBCs. Unsupervised clustering based on expression profiles revealed that 85% of MpTNBCs had a Mp-like expression signature. Interestingly, the Mp-like expression signature was identified in 12% of histologically defined non-MpTNBC. The pCR rate was lowest in the MpTNBC (18.9%) but similar between Mp-like TNBC (36.8%) and non-MpTNBC (42.2%). Conclusion: Early-stage MpTNBC has lower rates of pCR with NAT however those with pCR appear to have similar survival rates to non-MpTNBC with pCR. Notably, 16.2% of MpTNBC had PD after 2 cycles of AC NAT suggesting that a neoadjuvant approach with frequent imaging would reduce unnecessary exposure to inactive chemotherapy. 81% of MpTNBCs had either PD or suboptimal response to AC chemotherapy, thus novel treatment strategies need to be developed for this chemorefractory subtype of TNBC. PAM (PI3K/mTOR/AKT) pathway alterations were frequently detected in MpTNBCs and novel inhibitors should be further tested. Citation Format: Nour Abuhadra, Clinton Yam, Ryan Sun, Lei Huo, Jason White, Elizabeth Ravenberg, Beatriz Adrada, Aysegul Sahin, Jennifer Litton, Bora Lim, Naoto T Ueno, Banu Arun, Debu Tripathy, Senthil Damodaran, Rashmi Murthy, Vicente Valero, Gabriel Hortobagyi, Nuhad Ibrahim, Alastair Thompson, Anthony Lucci, Elizabeth Mittendorf, Stacy Moulder, Jeffrey Chang. Prospective evaluation of patients with metaplastic (Mp) triple negative breast cancer (TNBC): Molecular characteristics and outcomes with neoadjuvant therapy (NAT) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-04.

Abstract PS7-12: Impact of race/ethnicity on triple negative breast cancer molecular features, treatment response and clinical outcomes in patients receiving neoadjuvant therapy

Abstract Background: Triple negative breast cancer (TNBC) disproportionally impacts Black and Hispanic women and is suggested to be partly responsible for disparities observed in breast cancer mortality. We sought to evaluate the impact of race/ethnicity on TNBC molecular subtype, immune profile, pathologic complete response (pCR) and recurrence free survival (RFS). Methods: The ARTEMIS trial (NCT02276443) uses imaging response and molecular profiling to personalize neoadjuvant chemotherapy in early stage TNBC. After 4 cycles of AC, patients with chemo-sensitive disease receive standard taxane-based therapy, while those with chemo-resistant disease are offered therapeutic trials based upon molecular profiling. Pathologic response was assessed at surgery. Patients self-reported race/ethnicity was categorized as Asian, Black/African-American, Hispanic/Latino and White (non-Hispanic). Patients were excluded if no race or ethnicity was reported. Clinical and pathologic factors were recorded and compared. Gene expression profiling was performed by RNAseq to determine Vanderbilt signature. PD-L1 and Androgen Receptor (AR) were determined by immunohistochemistry. Frequencies at which various factors were observed by race/ethnicity were calculated and Fisher’s exact test performed to determine statistical significance. Kaplan-Meier analysis was used to estimate survival stratified by pCR status and race/ethnicity. Results: Among 321 women enrolled in ARTEMIS, 26 (8.1%) were classified as Asian, 50 (15.6%) as Black, 59 (18.4%) as Hispanic and 186 (57.9%) as White. Demographic and clinical features were similar, except Black women were more likely to have BMI ≥30 (70.0%, p<0.001). Comparing by race/ethnicity, there was no statistically significant difference in tumor histology, tumor size, nodal status, clinical stage, chemo-resistant disease, type of surgery or receipt of radiation. A trend toward higher proportion of N3 disease was observed in Black women (24.0%) compared to other groups (p=0.054). Tumor profiling results are listed in Table 1. No statistically significant difference was observed by race/ethnicity in Vanderbilt signature, presence of PD-L1 or stromal tumor infiltrating lymphocytes (sTIL) status. More AR-positive tumors were identified in Asian women (64%, p=0.007). pCR and RCB status did not significantly vary by race/ethnicity however, higher proportion of RCB-III disease was identified in Black (14%) and Hispanic women (16.9%) as compared to Asian (3.8%) and White (8.6%) women (p=0.164). At median follow up of 23.8 months (range 3.4-51.1), there was no statistically significant difference in RFS by race/ethnicity. Conclusion: Among this population of patients with TNBC treated with neoadjuvant chemotherapy there was no statistically significant difference observed in TNBC Vanderbilt signature, PD-L1 staining, sTIL, pCR or RFS by race/ethnicity. Asian women were found to have a higher incidence of AR-positive subtype. Numerically higher rates of N3 stage in Black women and RCB-III classification in Black and Hispanic women were identified, however not statistically significant. Larger cohorts of patients are needed to further investigate these findings. Table 1. TNBC profiling compared by race/ethnicity.Total n (%)Asian n (%)Black n (%)Hispanic/Latino n (%)White n (%)p valueVanderbilt signature n (%) Basal like (BL1) Basal like 2 (BL2) Immunomodulatory (IM) Luminal androgen receptor (LAR) Mesenchymal (M) Mesenchymal stem-like (MSL) Unstable (UNS)231 50 (21.6) 25 (10.8) 42 (18.2) 22 (9.5) 48 (20.8) 14 (6.0) 30 (13.0)21 (9.1) 0 (0.0) 4 (19.0) 5 (23.8) 3 (14.3) 5 (23.8) 1 (4.8) 3 (14.3)35 (15.2) 9 (25.7) 5 (14.3) 6 (17.1) 2 (5.7) 7 (20.0) 1 (2.9) 5 (14.3)43 (18.6) 14 (32.5) 3 (7.0) 10 (23.2) 5 (11.6) 6 (14.0) 2 (4.7) 3 (7.0)132 (57.1) 27 (20.5) 13 (9.8) 21 (15.9) 12 (9.1) 30 (22.7) 10 (7.6) 19 (14.4)NSAndrogen Receptor n (%) Positive (>=10%) Negative (<10%)311 109 (35.0) 202 (65.0)25 (8.0) 16 (64.0) 9 (36.0)49 (15.8) 11 (22.4) 38 (77.6)57 (18.3) 19 (33.3) 38 (66.7)180 (57.9) 63 (35.0) 117 (65.0)0.007PD-L1 n (%) None >1298 212 (71.1) 86 (28.9)24 (8.1) 15 (62.5) 9 (37.5)47 (15.8) 33 (70.2) 14 (29.8)57 (19.1) 40 (70.2) 17 (29.8)170 (57.0) 124 (72.9) 46 (27.1)NSStromal tumor infiltrating lymphocytes (sTIL) n (%) High (>=20%) Low (<20%)319 107 (33.5) 212 (66.5)26 (8.1) 12 (46.2) 14 (53.8)50 (15.7) 13 (26.0) 37 (74.0)58 (18.2) 21 (36.2) 37 (63.8)185 (58.0) 61 (33.0) 124 (67.0)NS Citation Format: Mediget Teshome, Ryan Sun, Elizabeth E. Ravenberg, Abenaa Brewster, Mariana Chavez-MacGregor, Jason B. White, Stacy Moulder. Impact of race/ethnicity on triple negative breast cancer molecular features, treatment response and clinical outcomes in patients receiving neoadjuvant therapy [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-12.

Abstract PD9-02: Personalized ctDNA as a predictive biomarker in high-risk early stage breast cancer (EBC) treated with neoadjuvant chemotherapy (NAC) with or without pembrolizumab (P)

Abstract Background: In the I-SPY 2 TRIAL, the addition of P to standard NAC resulted in more than doubling of the pathologic complete response (pCR) rates for both hormone receptor-positive (HR+)/HER2- and triple-negative (TN) early breast cancer (EBC) patients (pts) compared to NAC only (Nanda et al, JAMA Oncol, 2020). At 3 years, distant recurrence-free survival (DRFS) rates in pts with pCR following NAC+P was >95%. We hypothesized that ctDNA can serve as a predictive biomarker of response and survival in pts treated with NAC. Methods: A personalized ctDNA test (Signatera) was performed on 511 serial plasma samples from 138 pts with high-risk HR+/HER2- (n=77) or TN (n=61) stage II/III EBC. Pts received P with paclitaxel (Tx) followed by AC (P arm, n=42) or standard NAC only (n=96), an exploratory subset of pts evaluated for P efficacy. Plasma was collected; pretreatment (T0), 3 weeks after treatment initiation (T1), between Tx+/-P and AC regimens (T2), and prior to surgery (T3). ctDNA was deemed positive with a minimum of 2 of the pt specific tumor mutation fragments detected in cfDNA. Association of ctDNA with response and survival was analyzed using logistic and Cox regressions with pCR and DRFS as endpoints. Median follow-up was 2.8 years. Results: Detection of ctDNA decreased over time (P arm: T0-81%, T1-50%, T2-19%, T3-3%) and NAC only: T0-82%, T1-65%, T2-26%, T3-10%). ctDNA data at T0 and T1 was available for 96% (132/138) of pts in P arm or NAC only (Table). Among ctDNA+ patients at baseline, clearance at T1 was significantly associated with pCR (OR=1.92, ctDNA+/-; OR=0.27, ctDNA+/+; LR p<0.001). This association remained significant after adjustment for HR status and treatment (LR p<0.001) and P arm or NAC only (P: LR p=0.03; NAC: LR p=0.01). ctDNA data at T0, T1, and T2 was available for 86% (118/138) pts. (Table). Among all ctDNA+ pts at baseline, dynamics through T2 was associated with pCR (OR=1.44, ctDNA+/-/-; OR=0.33, ctDNA+/+/-, OR=0.12, ctDNA+/+/+; LR p=0.0011). This association remained significant when adjusted for HR status and treatment (LR p<0.001). Analysis within individual treatments showed significant association for NAC (LR p=0.040) and a non-significant trend in NAC+P (LR p=0.063), likely due to smaller sample size. All pts who achieved pCR were ctDNA- at T3 (n=34). Among those who failed to achieve pCR (n=81), DRFS was significantly better in ctDNA- (n=72/81; 20 in P and 52 in NAC) versus ctDNA+ pts (n=9/81; 1 in P and 8 in NAC) (adjusted HR 0.13; 95% CI 0.05-0.37). Conclusions: These exploratory results align with our previous findings that early clearance of ctDNA during NAC treatment was significantly associated with increased likelihood of achieving pCR. Additionally, we show that ctDNA clearance can be an early surrogate marker for therapy response assessment. Residual ctDNA after neoadjuvant treatment was a significant predictor of metastatic recurrence and death. Personalized monitoring of ctDNA during the course of NAC is feasible and provides information that can be combined with imaging and pathology, and may help to optimize decision making for de-escalation or escalation of therapy. Larger studies are ongoing. ctDNA dynamics and pCRctDNA status at T0 and T1 (n=132)ctDNA status at T0, T1, and T2 (n=118)ctDNA-/-ctDNA+/-ctDNA+/+ctDNA-/-/-ctDNA+/-/-ctDNA+/+/-ctDNA+/+/+Total, n (%)24 (18)28 (21)80 (61)22 (19)24 (20)43 (36)27 (23)pCR, n (%)9 (38)15 (54)11 (14)9 (41)12 (50)8 (19)2 (7)No pCR, n (%)15 (63)13 (46)69 (86)13 (59)12 (50)35 (81)25 (93) Citation Format: Mark Jesus M Magbanua, Denise Wolf, Derrick Renner, Svetlana Shchegrova, Lamorna Brown Swigart, Christina Yau, Gillian Hirst, Hsin-Ta Wu, Ekaterina Kalashnikova, Antony Tin, Amy Delson, Douglas Yee, Angela DeMichele, Raheleh Salari, Angel Rodriguez, Bernhard Zimmermann, Himanshu Sethi, Alexey Aleshin, Paul Billings, Laura Esserman, Minetta Liu, Rita Nanda, Laura van ‘t Veer, I-SPY 2 Investigators. Personalized ctDNA as a predictive biomarker in high-risk early stage breast cancer (EBC) treated with neoadjuvant chemotherapy (NAC) with or without pembrolizumab (P) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD9-02.

Abstract OT-13-01: A phase I study of preoperative ipilimumab, nivolumab, and talimogene laherparepvec for localized breast cancer

Abstract Background: Immunotherapy has emerged as a novel therapeutic strategy in many solid malignancies. In breast cancer, treatment with checkpoint inhibitors alone showed minimal response rates, likely because breast cancers are not sufficiently immunogenic to induce adequate baseline T cell activation. Talimogene laherparepvec (T-VEC) is an attenuated herpes simplex virus 1 (HSV-1) engineered to introduce the GM-CSF gene selectively into tumor cells to thereby enhance the immunogenicity of transduced tumor cells. T-VEC has been approved in the treatment of patients with advanced melanoma and injectable tumors. In a phase 1b clinical trial, T-VEC was well tolerated in combination with immunotherapy in patients with advanced melanoma. We evaluated the safety and tolerability of T-VEC, nivolumab, and ipilimumab in the preoperative treatment of early stage localized triple-negative breast cancer (TNBC) and hormone receptor (HR)-positive breast cancer. Trial design and eligibility criteria: This is a single site open-label phase 1b window of opportunity trial of neoadjuvant T-VEC in combination with nivolumab and ipilimumab in patients with localized breast cancer. Twenty patients with localized TNBC or HR-positive breast cancer with palpable tumors will be included. T-VEC is administered intratumorally in week 1 (106 plaque-forming units/mL [pfu/ml]) and then every 3 weeks (108 plaque-forming units/mL [pfu/ml]) for a total of 3 injections. Nivolumab (240 mg) is administered intravenously in week 1 and every 2 weeks for a total of 4 infusions. Ipilimumab (1 mg/kg) is administered intravenously in week 1 and week 6 for a total of 2 infusions. Breast cancer surgery will be carried out after completion of study treatment. Neoadjuvant chemotherapy could be administered before or after study treatment. Study objectives: The primary objective is to evaluate the safety and tolerability of T-VEC in combination with nivolumab and ipilimumab in this population. The secondary objectives are 1) to assess tumor response to T-VEC, nivolumab, and ipilimumab and 2) to descriptively analyze surgical specimens for evidence of tumor necrosis and inflammatory infiltration on histopathological examination. Present accrual: To date, 5 patients have been enrolled. As described above, the projected sample size is 20 patients. Clinical trials identification: NCT04185311 Citation Format: Vina P. Nguyen, Helena R. Chang, Maggie L. DiNome, Denise K. Oseguera, Deborah J. Wong, Anthony T. Nguyen, Stephen L. Shiao, John A. Glaspy. A phase I study of preoperative ipilimumab, nivolumab, and talimogene laherparepvec for localized breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-13-01.

Abstract PS9-18: Relative risk of various endocrinopathies associated with the use of chemoimmunotherapy for triple-negative breast cancer: A systematic review and meta-analysis

Abstract Background: Chemoimmunotherapy (CPI+C) is an important addition to the triple-negative breast cancer (TNBC) treatment. However, immune checkpoint inhibitors (CPIs) are frequently associated with significant endocrine toxicities. We conducted a systematic review and meta-analysis of phase 3, randomized controlled trials (RCTs) to determine the relative risk of various endocrinopathies associated with use of CPI+C regimens for the treatment of TNBC. Methods: We conducted a comprehensive search in the PUBMED, MEDLINE, EMBASE, San Antonio Breast Cancer Symposium, and American Society of Clinical Oncology meeting abstracts as per PRISMA guidelines from inception until June 2020. We included phase 3 RCTs used CPI+C in the intervention arm for the treatment of TNBC and reported the number of events for various endocrinopathies. We used the Mantel-Haenszel method and the random effects model to calculate the pooled risk ratio (RR) with a 95% confidence interval (CI). Heterogeneity was tested with the I2 value and Cochran’s Q statistics. An RR of < 1 was considered to be favorable for the CPI+C, and an RR of > 1 was considered to be unfavorable for the CPI+C. A P-value ≤ 0.05 was considered statistically significant. Results: Two phase 3 RCTs — IMpassion130 and KEYNOTE-522 — were included in the final analysis. The CPI+C arm included 1233 patients, and the placebo-chemotherapy (P+C) arm included 827 patients. While the IMpassion130 was done in unresectable, locally advanced or metastatic TNBC patients at the first-line setting, the KEYNOTE-522 was done in early stage TNBC patients. For the KEYNOTE-522 study, we used data from the neoadjuvant phase, as in the adjuvant phase, only CPI was continued. The number of patients in the adjuvant phase also differed from the neoadjuvant phase which made it difficult to select appropriate denominator for the RR calculation. Some important characteristics of these studies are included in the table 1. The incidence of any-grade hypothyroidism was 15% in the CPI+C arm vs 3.86% in the P+C arm. The pooled RR of any-grade hypothyroidism was 4.03 (95% CI: 2.79-5.82, P < 0.00001, I2 = 0%). The incidence of any-grade hyperthyroidism was 4.54% in the CPI+C arm vs 1.2% in the P+C arm. The pooled RR of any-grade hyperthyroidism was 3.73 (95% CI: 1.89-7.34, P = 0.0001, I2 = 0%). The incidence of any-grade adrenal insufficiency was 1.78% in the CPI+C arm vs 0% in the P+C arm. The pooled RR of any-grade adrenal insufficiency was 12.87 (95% CI: 1.70-97.34, P = 0.01, I2 = 0%). The incidence of type 1 diabetes mellitus was 0.24% in the CPI+C arm vs 0.24% in the P+C arm. The RR for type 1 diabetes mellitus was not significantly different between the arms — RR: 0.91 (95% CI: 0.14-5.96, P = 0.92, I2 = 0%). Conclusions: The relative risk of hypothyroidism, hyperthyroidism, and adrenal insufficiency were significantly higher with the use chemoimmunotherapy compared to chemotherapy alone in TNBC patients. CPI induced endocrinopathies are often permanent and require long-term treatment. However, treatment discontinuation is not necessary for CPI induced endocrinopathies. A careful monitoring of symptoms and endocrine functions, and initiation of appropriate treatments are crucial to reduce endocrine related morbidities and mortalities in these patients. Table 1. Characteristics of the included studies.StudyAuthor/Journal/YearSettingCPI+C armP+C armRandomizationNo.of patients (CPI+C)No. of patients (P+C)IMpassion130Schmid/NEJM/2018Advanced TNBCAtezolizumab + nab-paclitaxelPlacebo + nab-paclitaxel1:1452438KEYNOTE-522Schmid/NEJM/2020Stage II and III TNBCPembrolizumab + paclitaxel + carboplatin + adriamycin or epirubicin + cyclophosphamidePlacebo + paclitaxel + carboplatin + adriamycin or epirubicin + cyclophosphamide2:1781389CPI+C: chemoimmunotherapy; NEJM: The New England Journal of Medicine; P+C: placebo + chemotherapy; TNBC: triple-negative breast cancer. Citation Format: Nusrat Jahan, Sariya Wongsaengsak, Sakshi Singal, Shabnam Rehman, Fred Hardwicke, Catherine Jones. Relative risk of various endocrinopathies associated with the use of chemoimmunotherapy for triple-negative breast cancer: A systematic review and meta-analysis [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-18.

Abstract PS17-14: Evaluating the efficacy of immunotherapy in triple negative breast cancer

Abstract The breast cancer microenvironment comprises a complex stroma including tumor-infiltrating lymphocytes (TILs), which can either stimulate tumor progression or promote anti-tumor immunity in response to tumor-derived cues. In general, of all clinical subtypes, triple-negative breast cancer (TNBC) is characterized by the most extensive infiltration of TILs within tumor stroma, which is consistent with the observation that TNBC seems to clinically respond to immunotherapies at the highest rates. Immune checkpoint blockade (ICB), an immunotherapy that promotes prolonged activation of cytotoxic immune cells to mount robust anti-tumorigenic responses, has yielded limited success in treating breast cancer. IMpassion130 was the first clinical trial to indicate that combining anti-PD-L1 with standard-of-care chemotherapy (nab-paclitaxel) to treat TNBC increases progression-free survival in patients exclusively those with PD-L1 positive tumors. Furthermore, the KEYSTONE-522 trial showed that administering anti-PD-1 in addition to various neoadjuvant chemotherapies increased the pathologic complete response in early stage TNBC patients. Despite promising evidence for immunotherapy success, both clinical trials lacked an experimental ICB-only group, and thus cannot address the therapeutic benefit of ICB alone, or which chemotherapy combination would maximize this benefit. Finally, mechanisms of resistance to ICB in breast cancer remain unexplored. We sought to model ICB response in vivo to elucidate the mechanisms responsible for immunotherapy efficacy in breast cancer, explore the synergistic effects of ICB with chemotherapies, and model ICB resistance.In this study, we investigated the efficacy of anti-PD-L1 as single-agent or in combination with paclitaxel or doxorubicin in the EMT6 (Balb/c) orthotopic mammary tumor model. In this model, single-agent immunotherapy was efficacious in reducing primary tumor growth compared to combination treatment, with a small proportion of complete responses, whereas modest benefit was observed with either chemotherapy alone. Following two rounds of treatment, we analyzed the tumor-immune microenvironment by flow cytometry and gene expression analysis. Anti-PD-L1 alone or in combination with either chemotherapy enhanced infiltration of cytotoxic and effector T cell as well as natural killer cells into the tumor microenvironment. Using gene expression analysis, we observed elevated expression of myeloid recruitment and activation markers in combination-treated tumors, supporting a known role of chemotherapy-induced cell death in myeloid recruitment; however as chemotherapy did not add benefit to tumor response or survival, it is unclear if this effect is detrimental or supportive. Interestingly, completely responsive anti-PD-L1 treated tumors that eventually recurred retained resistance to ICB upon re-implantation in naïve recipient mice, suggesting that tumor-intrinsic factors may contribute to resistance.Herein, we explore an in vivo model that corroborates clinical response to combinatorial immunotherapy approaches in breast cancer patients. We report the immunogenic efficacy of single-agent ICB that upregulates tumoricidal immune cell infiltration into the primary tumor, thereby controlling tumor growth, albeit without achieving complete response in all mice. Additionally, post-therapy recurrent tumors retain resistance upon transplantation, indicating tumor-specific adaptive resistance. This study has potentially significant clinical implications for re-evaluating the contributions of chemotherapy in combination with ICB in TNBC patients. Citation Format: Ann Hanna, Paula I. Gonzalez-Ericsson, Violeta Sanchez, Melinda E. Sanders, Justin M. Balko. Evaluating the efficacy of immunotherapy in triple negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-14.

Abstract PS6-56: Clinical validity of compartmental analysis of tumor-infiltrating lymphocytes (TIL) in triple-negative breast cancer (TNBC) - The key is in spatial morphology?

Abstract INTRODUCTIONAnalyzes reported to date on TIL in TNBC have evaluated mostly stromal (sTIL) and possibly intratumoral TIL (iTIL), but none evaluated TIL spatially, separately in compartments of central tumor (CT) and invasive margin (IM). Also, none evaluated connection between TIL and other clinicopathological factors. METHODSWe retrospectively analyzed consecutive sample of 152 early TNBC patients treated at our institution 2009-2012. TIL were assessed morphologically, by hematoxylin - eosin (HE), using standard formalin - fixed - paraffin - embedded (FFPE) samples, according to recommendation of International Working Group for Evaluation of TIL, both sTIL and iTIL, spatially, in compartments of CT and IM. Available clinicopathological variables were analyzed, and correlations of all paramethers were calculated. RESULTSMorphological analysis of TIL spatially by compartments showed as follows: median overall sTIL content was 19%, iTIL 5%, TIL in CT 5%, TIL at IM 18%, sTIL in CT 5%, iTIL in CT 1%, sTIL at IM 30%, and iTIL at IM 5%. Intermediate or high TIL content, defined as ≥10% was present in 48% cases of sTIL in CT, 23% of iTIL in CT, 86% of sTIL at IM, and in 47% of iTIL at IM cases. Quarter of patients had TIL>50% in any of four compartments. There was statistically significant positive correlation between sTIL in CT and age and menopausal status, and also tumor size (T), but w/out correlation to histologic subtype, nodal (N) status, grade, and Ki67; iTIL in CT were statistically significantly positively correlated to histologic subtype (precisely to NOS subtype), but negatively to age and menopausal status, exactly opposite to sTIL in this section, and w/out correlation to other tumor characteristics, such as T, N, grade or Ki67; sTIL on IM, as well as iTIL on IM, showed statistically significant correlation to grade and Ki67, and no correlation to age and menopausal status. DISCUSSIONSection analysis reveals higher density of TIL content at IM, which directs attention towards this neglected tumoral compartment and it's possible role. It also shows, although in small numbers, that possibly iTIL, especially those at IM, could actually not only, as thought so far, serve as ,,satellites“ to sTIL, but an entirely autonomous, and even opposite biomarker. Moreover, all that could be concluded from just a simple and cheap HE morphological analysis of standard tumor specimen. Citation Format: Ana Tecic Vuger, Robert Separovic, Ljubica Vazdar, Mirjana Pavlovic, Sanda Sitic, Ingrid Belac-Lovasic, Damir Vrbanec. Clinical validity of compartmental analysis of tumor-infiltrating lymphocytes (TIL) in triple-negative breast cancer (TNBC) - The key is in spatial morphology? [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-56.

Imbalance of Molecular Module of TINCR-miR-761 Promotes the Metastatic Potential of Early Triple Negative Breast Cancer and Partially Offsets the Anti-Tumor Activity of Luteolin.

BackgroundTriple negative breast cancer (TNBC) poses a great threat to patient prognosis. LncRNA-miRNA is a molecular module formed by a long non-coding RNA (LncRNA) and a microRNA (miRNA) that mediates the metastatic potential of tumours such as TNBC, and luteolin (LU) is a natural compound with anti-TNBC activity.ObjectiveWe aim to explore the regulatory mechanism of terminal differentiation-induced non-coding RNA (TINCR)-miR-761 molecular module in early TNBC, as well as its influence on anti-tumor activity of LU.MethodsThe serum was collected from TNBC patients in early stage to detect the expression of TINCR and miR-761 using RT-PCR. Transwell method was applied for the determination of cell migration and invasion, Western blot for epithelial–mesenchymal transition (EMT), flow cytometry (FCM) for cell apoptosis, and dual luciferase reporter and RNA pull-down experiment for the verification of the targeted relationship between TINCR and miR-761.ResultsBoth TINCR and miR-761 were up-regulated in the serum of patients with early TNBC and the area under the curve (AUC) of the two for distinguishing TNBC from BC was not less than 0.850. In the cell function tests, down-regulation of TINCR or miR-761 notably suppressed the metastatic potentials (cell migration, invasion and EMT) of TNBC cells were remarkably inhibited, while up-regulation of TINCR or miR-761 notably promoted the metastatic potentials. We also confirmed that TINCR acts as the molecular sponge of miR-761, and has positive regulation on it. Besides, LU can significantly down-regulate TINCR and miR-761, and partially offset the anti-TNBC activity of LU when they were abnormally up-regulated, which was mainly reflected in the decrease of anti-proliferation and pro-apoptotic ability of LU against TNBC.ConclusionThere is an imbalance of TINCR-miR-761 molecular module in early TNBC, which may be a potential new therapeutic target of TNBC.

Germline BRCA1/2 mutations and severe haematological toxicities in patients with breast cancer treated with neoadjuvant chemotherapy

BackgroundBRCA1 and BRCA2 play a central role in DNA repair. Therefore, patients harbouring germline (g) BRCA1/2 mutations (m) treated with chemotherapy might be at higher risk of haematological toxicities. MethodsPatients from German Breast Group (GBG) and Arbeitsgemeinschaft Gynäkologische Onkologie-breast group studies with early triple-negative breast cancer (TNBC) and known gBRCA1/2m status treated with anthracycline-taxane-based neoadjuvant chemotherapy were analysed. Primary objective was the rate of neutropenia grade (G)III–IV in cycle 1 (C1). Secondary objectives included effects on overall and other haematological toxicities GIII-IV in C1, cumulative haematological toxicity across all cycles, relative total dose intensity, and granulocyte-colony stimulating factor prophylaxis. Haematological toxicities under taxanes, carboplatin, and cyclophosphamide were explored. ResultsTwo hundred nine of 1171 (17.8%) evaluated patients had gBRCA1/2m. In C1, 37.4% gBRCA1/2m versus 35.7% wild-type patients had neutropenia GIII-IV (P = 0.683). For C1, gBRCA1/2m predicted neither for neutropenia GIII-IV (odds ratio [OR]: 1.26, 95% confidence intervals [CI]: 0.87–1.82, P = 0.226) nor for other haematological toxicities GIII-IV (OR: 0.91, 95% CI: 0.64–1.31, P = 0.625) in multivariable regression models. Analyses of cumulative toxicities across all cycles yielded similar results except thrombocytopaenia GIII-IV, which was increased in gBRCA1m patients. In patients treated with taxanes, the rate of haematological toxicities GIII-IV was higher in gBRCA1/2m compared with wild-type (59.5% versus 43.1%; p < 0.001). No difference was seen under cyclophosphamide or platinum-containing chemotherapies. ConclusionsgBRCA1/2m was not associated with higher risk of overall severe haematological toxicities in the first cycle or cumulatively across all cycles under standard chemotherapy for TNBC. Under taxane, patients with gBRCA1/2m might have a higher risk of haematological toxicities GIII-IV, requiring further research.

Immunotherapy in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is an aggressive subtype of mammary carcinoma. A subset of TNBC is immune activated, suggesting that immunotherapy may be a viable treatment strategy. Phase III clinical trials have shown that atezolizumab or pembrolizumab is well-tolerated in combination with chemotherapy, with progression-free survival benefit in metastatic programmed death ligand-1 (PD-L1)-positive TNBC patients treated first line. Based on IMpassion130, the combination of atezolizumab and nab-paclitaxel is now considered a standard of care for the treatment of PD-L1-positive advanced TNBC. In early TNBC, pembrolizumab and atezolizumab have been tested in combination with standard neoadjuvant chemotherapy, resulting in a higher complete pathologic response rate than standard neoadjuvant chemotherapy alone, regardless of disease PD-L1 status. These findings establish proof of principle for immunotherapy in both early and advanced TNBC. High priorities for the field include developing more active immunotherapy combination regimens and more refined biomarkers that optimally identify patients most likely to benefit from immunotherapy.

Update on systemic treatment in early triple negative breast cancer.

Triple negative breast cancer (TNBC) is a heterogeneous disease representing about 15% of all breast cancers. TNBC are usually high-grade histological tumors, and are generally more aggressive and difficult to treat due to the lack of targeted therapies available, and chemotherapy remains the standard treatment. There is a close relationship between pathological complete response after chemotherapy treatment and higher rates of disease-free survival and overall survival. In this review of systemic treatment in early triple negative breast cancer, our purpose is to analyze and compare different therapies, as well as to highlight the novelties of treatment in this breast cancer subtype.

Patterns of Relapse Related to High Expression of Ki-67 After Neoadjuvant Chemotherapy in Triple Negative Breast Cancer

Introduction: Triple negative breast cancer (TNBC) has been classically considered a high-risk subtype. Early TNBC is usually managed with neoadjuvant chemotherapy (NAC). Residual disease after NAC is generally considered a surrogate marker for event free survival in these patients. The aim of this study was to explore the relationship between high Ki-67 expression in residual disease after NAC and disease relapse. Material and methods: This is a retrospective study of 121 patients diagnosed with TNBC, treated with neoadjuvant chemotherapy in our institution between 2008 and 2018. Clinical features, systemic and surgical therapy and pathological response were analyzed. Ki-67 expression was performed in the post-NAC surgical specimens when a pathological complete response (pCR) was not achieved. Results were correlated with number and type of relapse, and survival. Results: Eighty-one patients (67%) achieved a pCR with a median Ki-67 expression in the residual tumor of 22.5%. Thirteen patients (10.7%) relapsed and all of them belonged to the non-pCR group. In the non-relapse group, the median Ki-67 in the residual tumor was 10% compared to 40% found in the relapse group. (P=0.025). Median Ki-67 post NAC was 70% in those patients who developed a central nervous disease (CNS) relapse, 40% if was a nodal or bone recurrence and 28% if it was a visceral relapse. CNS recurrence was significantly associated with higher Ki-67 levels post NAC (P=0.010). Conclusions: Our results suggest that high expression levels of Ki-67 post-NAC could define different patterns of relapse in TNBC patients treated with NAC.

Neoadjuvant Chemotherapy in Early Triple-Negative Breast Cancer: A Pairwise and Network Meta-Analysis of Pathological Complete Response.

We performed a pairwise and network meta-analysis to compare pathological complete response (pCR) among neoadjuvant chemotherapy in patients with triple-negative breast cancer. We searched PubMed for randomized clinical trials between January 1, 2000 and December 1, 2020. s from meetings were also searched. A frequentist random-effect model was applied to compare pCR and toxicities. The P-score was used to rank treatment effects. Nineteen trials with 16 treatments and 7794 patients were included. On the basis of SoC, the addition of carboplatin (OR = 1.82, 95% CI, 1.24 to 2.68, P < .01) and the addition of checkpoint inhibitors (OR = 1.69, 95% CI, 1.23 to 2.32, P < .01) increased pCR in pairwise meta-analysis; compared with paclitaxel, nab-paclitaxel did not improve pCR rates (OR = 1.81, 95% CI, .80 to 4.12, P = .16). The anthracycline-sparing regimen led to similar pCR compared with the anthracycline-containing regimen (OR = 1.50, 95% CI, .82 to 2.76, P = .19). In network meta-analysis, the addition of carboplatin plus a PD-1 inhibitor (pembrolizumab), carboplatin plus bevacizumab, and carboplatin plus veliparib ranked as the top three treatments for achieving pCR, with corresponding P-scores of .91, .84, and .72, respectively. Among patients with homologous recombination deficiency, the addition of carboplatin (OR = 1.31, 95% CI, .69 to 2.50, P = .41) or carboplatin plus PARP inhibitors (OR = 1.19, 95% CI, .58 to 2.47, P = .63) did not increase pCR. For triple-negative breast cancer, combining carboplatin with taxane-anthracycline-containing neoadjuvant chemotherapy could be the standard of care, and the combination containing checkpoint inhibitor is promising. However, their role in long-term oncologic outcome remains to be determined.

Clinical genomic profiling to identify actionable alterations for very early relapsed triple-negative breast cancer patients in the Chinese population

Background Triple-negative breast cancer (TNBC) represents about 19% of all breast cancer cases in the Chinese population. Lack of targeted therapy contributes to the poorer outcomes compared with other breast cancer subtypes. Comprehensive genomic profiling helps to explore the clinically relevant genomic alterations (CRGAs) and potential therapeutic targets in very-early-relapsed TNBC patients. Methods Formalin-fixed paraffin-embedded (FFPE) tumour tissue specimens from 23 patients with very-early-relapsed TNBC and 13 patients with disease-free survival (DFS) more than 36 months were tested by FoundationOne CDx (F1CDx) in 324 genes and select gene rearrangements, along with genomic signatures including microsatellite instability (MSI) and tumour mutational burden (TMB). Results In total, 137 CRGAs were detected in the 23 very-early-relapsed TNBC patients, averaging six alterations per sample. The mean TMB was 4 Muts/Mb, which was higher than that in non-recurrence patients, and is statistically significant. The top-ranked altered genes were TP53 (83%), PTEN (35%), RB1 (30%), PIK3CA (26%) and BRCA1 (22%). RB1 mutation carriers had shorter DFS. Notably, 100% of these patients had at least one CRGA, and 87% of patients had at least one actionable alteration. In pathway analysis, patients who carried a mutation in the cell cycle pathway were more likely to experience very early recurrence. Strikingly, we detected one patient with ERBB2 amplification and one patient with ERBB2 exon20 insertion, both of which were missed by immunohistochemistry (IHC). We also detected novel alterations of ROS1–EPHA7 fusion for the first time, which has not been reported in breast cancer before. Conclusions The comprehensive genomic profiling can identify novel treatment targets and address the limited options in TNBC patients. Therefore, incorporating F1CDx into TNBC may shed light on novel therapeutic opportunities for these very-early-relapsed TNBC patients.

Recent updates in systemic therapy of breast cancer: A brief narrative review

Breast cancer is the most common malignancy and the leading cause of cancer-related deaths in women globally. Systemic therapy of breast cancer has evolved rapidly in the past few years. In this brief review, we aim to summarize the potentially practice-changing recent updates in the management of breast cancer. We searched the PubMed database for randomized clinical trials for breast cancer treatment conducted over the past 2 years. In addition, abstracts and results of studies reported at major oncology meetings were evaluated. A total of 95 randomized clinical trials were included to prepare this review. Multiple new therapeutic options for almost all subsets of breast cancer have emerged in the past 2 years. Most importantly, for hormone-receptor-positive breast cancer, addition of abemaciclib to endocrine therapy in the adjuvant setting and alpelisib for PIK3CA-mutant refractory advanced disease have been shown to improve the survival outcomes. Addition of pembrolizumab or atezolizumab to neoadjuvant chemotherapy has significantly increased the pathological complete response rate for early triple-negative breast cancer, while adjuvant metronomic capecitabine for 1 year has led to improved disease-free survival. Moreover, adjuvant adotrastuzumab emtansine fared better than trastuzumab in the management of residual disease after neoadjuvant treatment for human epidermal growth factor receptor 2 (HER2)-positive breast cancer, while tucatinib and neratinib have shown meaningfully improved progression-free survival in HER2-positive advanced disease, including patients with cranial nervous system involvement. Expanding access to these advances is soon expected to transform the way we treat breast cancers.

Early triple-negative breast cancer in women aged ≥65: retrospective study of outcomes, resource useand costs, 2010-2016.

Aim: To examine real-world treatment patterns and outcomes in neoadjuvant and adjuvant settings for early-stage triple-negative breast cancer (TNBC). Patients & methods: Using the Surveillance, Epidemiology, and End Results-Medicare database, we identified patients (≥65years) with newly diagnosed stage II/III TNBC in 2010-2015 who had surgery plus neoadjuvant and/or adjuvant (systemic and/or radiation) therapy. Treatment, survival, healthcare resource useand costs were assessed through 2016. Results: Of 1569 patients (>99% women), 6%/74%/20% received neoadjuvant-only/adjuvant-only/both (neo+adj) therapies, respectively. Median overall survival was 23months/not reached (NR)/78months, with longer survival at stage II (NR/NR/78months) than stage III (22/43/38months). Mean per patient per month costs were $10,620 and $17,872 in neoadjuvant and adjuvant periods. Conclusion: These findings provide insights into clinical and economic outcomes for early-stage TNBC in 2010-2016.

Use of Immune Checkpoint Inhibitors in Early Triple-Negative Breast Cancer: Beyond the Early Conflicting Results

In the absence of estrogen, progesterone, and human epidermal growth receptor 2 (HER2) receptors, triple-negative breast cancer (TNBC) forms an aggressive subtype of breast cancer that constituents approximately 20% of all breast cancer cases and is more commonly seen in younger patients.1 Because the malignancy is refractory to targeted therapies blocking the hormonal and HER2 pathway, systemic anthracycline, or taxane-based chemotherapy and surgical removal of the tumor and radiation form the crux of the treatment.

Adjuvant chemotherapy and survival in women aged 70 years and older with triple-negative breast cancer: a Swedish population-based propensity score-matched analysis

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer associated with poor survival, in which adjuvant systemic treatments are limited to chemotherapy. Due to competing mortality risks and comorbidities, older patients with TNBC are often undertreated with adjuvant chemotherapy, and clinical trials on this problem are scarce, despite a growing patient population. This study aimed to assess outcomes for patients aged 70 years and older with TNBC with or without chemotherapy in a national population-based registry, to provide information that can assist in treatment decisions for these patients. In this population-based registry study, data on all patients aged 70 years and older diagnosed with primary early TNBC (larger than 5 mm in diameter and without distant metastasis) and surgically treated between Jan 1, 2009, and Dec 31, 2016, were retrieved from the Swedish National Breast Cancer Register, the Swedish Patient Register, and the Swedish Cause of Death Register. Patients with incomplete data (on oestrogen receptor, progesterone receptor, or human epidermal growth factor receptor 2 status, surgical procedure in the breast, or information about chemotherapy) were excluded. A propensity score-matched (PSM) model was used to examine the outcomes of adjuvant chemotherapy on 5-year breast cancer-specific survival (BCSS) and 5-year overall survival (OS), adjusted for age, tumour size, tumour grade, nodal status, and comorbidities. Of 1130 women eligible for analysis, 368 (32·6%) received adjuvant chemotherapy, 45 (4·0%) received neoadjuvant treatment, and 717 (63·5%) did not receive chemotherapy. 5-year BCSS was significantly improved in patients who received adjuvant chemotherapy (85% [95% CI 81-89]) compared with patients who did not receive chemotherapy (68% [64-72]; p<0·0001). A similar benefit was observed in 5-year OS (79% [95% CI 75-84] vs 49% [45-53]; p<0·0001). In our PSM analysis, 5-year BCSS in patients treated with adjuvant chemotherapy was 83% (95% CI 78-89), versus 73% (67-80; p=0·014) in patients not treated with chemotherapy. 5-year OS in patients treated with adjuvant chemotherapy was 75% (95% CI 69-82), versus 63% (57-71; p=0·029) in patients who did not receive chemotherapy. In this PSM registry analysis of surgically treated female patients aged 70 years and older with TNBC without distant metastasis, we identified a significant benefit both in 5-year BCSS and 5-year OS with adjuvant chemotherapy versus no chemotherapy, which persisted when adjusting for age and comorbidities. These results underline the importance of considering adjuvant chemotherapy in older patients. Knut and Alice Wallenberg Foundation, Assar Gabrielsson Foundation.

Insights for the application of TILs and AR in the treatment of TNBC in routine clinical practice

Triple negative breast cancer (TNBC), usually presenting with a very aggressive phenotype, is a heterogeneous entity. We aim to discuss new biomarkers, suitable for prognostic and predictive purposes. We retrospectively collected clinical variables and immunohistochemical characteristics of early TNBCs, specifically focusing on the prognostic and predictive significance of tumor infiltrating lymphocytes (TILs) and androgen receptor (AR) expression, assessing their correlation with clinical variables. Among 159 patients, TILs were significantly higher in younger patients and with lower BMI, and in tumors with higher ki-67 and greater nodal involvement; conversely, AR was significantly higher in older patients and in tumors with lower ki-67. Interestingly and in line with literature, both TILs level and ARs expression were lower within metastatic sites, in patients who developed distant metastases, compared to those found in the primary site. Small (pT1) and node negative tumors were highly represented and no correlation of either TILs or AR with prognosis could be observed. Our findings support the use of stromal TILs to identify a more aggressive, but chemo-sensitive phenotype, mostly represented in younger women, while AR may identify a less aggressive, slow-growing luminal TNBC subtype, more common among older patients. TILs and AR are worth implementing in routine clinical practice to refine prognosis even if, in our case series, we couldn’t identify a significant correlation of the two variables with either disease-free and overall survival.

Biomolecular Factors Represented by Bcl-2, p53, and Tumor-Infiltrating Lymphocytes Predict Response for Adjuvant Anthracycline Chemotherapy in Patients with Early Triple-Negative Breast Cancer.

Treatment of triple-negative breast cancer is challenging. Standard adjuvant tretment is considered to be the cobination of anthracycline and taxanes although the role of anthracyclines administered preoperatively remains controversial. Actually, some studies recommended taxane-only regimens. We reviewed literatures to examine whether tissue biomarkers available in an ordinary laboratory setting (eg, haematoxylin and eosin and immunohistochemistry) may predict response to adjuvant anthracyclines in patients with triple-negative breast cancer. Our review showed that Bcl-2, p53, and tumor-infiltrating lymphocytes (TILs) expression may become independent predictors for triple-negative breast cancer. This finding was based on data from retrospective studies, and, thus, randomized controlled study is needed to confirm the present results.