Immune Markers and Tumor-Related Processes Predict Neoadjuvant Therapy Response in the WSG-ADAPT HER2-Positive/Hormone Receptor-Positive Trial in Early Breast Cancer

Prognostic or predictive biomarkers in HER2-positive early breast cancer (EBC) may inform treatment optimization. The ADAPT HER2-positive/hormone receptor-positive phase II trial (NCT01779206) demonstrated pathological complete response (pCR) rates of ~40% following de-escalated treatment with 12 weeks neoadjuvant ado-trastuzumab emtansine (T-DM1) ± endocrine therapy. In this exploratory analysis, we evaluated potential early predictors of response to neoadjuvant therapy. The effects of PIK3CA mutations and immune (CD8 and PD-L1) and apoptotic markers (BCL2 and MCL1) on pCR rates were assessed, along with intrinsic BC subtypes. Immune response and pCR were lower in PIK3CA-mutated tumors compared with wildtype. Increased BCL2 at baseline in all patients and at Cycle 2 in the T-DM1 arms was associated with lower pCR. In the T-DM1 arms only, the HER2-enriched subtype was associated with increased pCR rate (54% vs. 28%). These findings support further prospective pCR-driven de-escalation studies in patients with HER2-positive EBC

Detection of circulating tumor cells using manually performed immunocytochemistry (MICC) does not correlate with outcome in patients with early breast cancer – Results of the German SUCCESS-A- trial

Background: Recently, the prognostic significance of circulating tumor cells (CTCs) in primary breast cancer as assessed using the Food-and-Drug-Administration-approved CellSearch® system has been demonstrated. Here, we evaluated the prognostic relevance of CTCs, as determined using manually performed immunocytochemistry (MICC) in peripheral blood at primary diagnosis, in patients from the prospectively randomized multicenter SUCCESS-A trial (EudraCT2005000490-21). Methods: We analyzed 23 ml of blood from 1221 patients with node-positive or high risk node-negative breast cancer before adjuvant taxane-based chemotherapy. Cells were separated using a density gradient followed by epithelial cell labeling with the anti-cytokeratin-antibody A45-B/B3, immunohistochemical staining with new fuchsin, and cytospin preparation. All cytospins were screened for CTCs, and the cutoff for positivity was at least one CTC. The prognostic value of CTCs with regard to disease-free survival (DFS), distant disease-free survival (DDFS), breast-cancer-specific survival (BCSS), and overall survival (OS) was assessed using both univariate analyses applying the Kaplan–Meier method and log-rank tests, and using multivariate Cox regressions adjusted for other predictive factors. Results: In 20.6% of all patients (n = 251) a median of 1 (range, 1–256) CTC was detected, while 79.4% of the patients (n = 970) were negative for CTCs before adjuvant chemotherapy. A pT1 tumor was present in 40.% of patients, 4.8% had G1 grading and 34.6% were node-negative. There was no association between CTC positivity and tumor stage, nodal status, grading, histological type, hormone receptor status, Her2 status, menopausal status or treatment. Univariate survival analyses based on a median follow-up of 64 months revealed no significant differences between CTC-positive and CTC-negative patients with regard to DFS, DDFS, BCSS, or OS. This was confirmed by fully adjusted multivariate Cox regressions, showing that the presence of CTCs (yes/no) as assessed by MICC did not predict DFS, DDFS, BCSS or OS. Conclusions: We could not demonstrate prognostic relevance regarding CTCs that were quantified using the MICC method at the time of primary diagnosis in our cohort of early breast cancer patients. Further studies are necessary to evaluate if the presence of CTCs assessed using MICC has prognostic relevance, or can be used for risk stratification and treatment monitoring in adjuvant breast cancer. Trial registration The ClinicalTrial.gov registration ID of this prospectively randomized trial is NCT02181101; the (retrospective) registration date was June 2014 (study start date September 2005)

MUC1 (CA27.29) before and after Chemotherapy and Prognosis in High-Risk Early Breast Cancer Patients

Simple Summary CA27.29 (MUC1) is a well described biomarker for prediction of prognosis and treatment efficacy. CA27.29 is mainly evaluated in the preoperative setting. However, testing of postoperative levels and additional assessment after chemotherapy might be more informative for analyzing the usefulness of CA27.29 in relation to the efficacy of chemotherapy. Thus, both pre- and post-chemotherapy values were assessed from patients enrolled in the breast cancer SUCCESS-A trial. Pre-chemotherapy assessment was associated with disease-free survival. It had no prognostic value in node-negative patients, but there was a clear association in node-positive patients. Furthermore, it was shown that post-chemotherapy CA27.29 assessment did not add any prognostic value, either on its own or in addition to pre-chemotherapy assessment. In conclusion, this indicates that pre- and post-chemotherapy values do not provide additional information. However, pre-chemotherapy CA27.29 could be a suitable tool to identify a group with unfavorable prognosis among node-positive patients. Abstract Soluble MUC1 has been discussed as a biomarker for predicting prognosis, treatment efficacy, and monitoring disease activity in breast cancer (BC) patients. Most studies in adjuvant settings have used preoperative assessment. This study, part of the SUCCESS-A trial (NCT02181101), assessed the prognostic value of soluble MUC1 before and after standard adjuvant chemotherapy. Patients with high-risk BC were treated within the SUCCESS-A trial with either three cycles of 5-fluorouracil, epirubicin, and cyclophosphamide followed by three cycles of docetaxel or three cycles of FEC followed by three cycles of docetaxel and gemcitabine. Cox regression analyses were performed to investigate the prognostic value of CA27.29 before and after chemotherapy relative to disease-free survival (DFS), along with established BC prognostic factors such as age, body mass index, tumor size, nodal status, estrogen receptor, progesterone receptor, HER2 status, and grading. Pre-chemotherapy and post-chemotherapy CA27.29 assessments were available for 2687 patients of 3754 randomized patients. Pre-chemotherapy CA27.29 assessment was associated with DFS in addition to established prognostic factors. It had no prognostic value in node-negative patients, but there was a clear association in node-positive patients. Post-chemotherapy CA27.29 assessment did not add any prognostic value, either on its own or in addition to pre-chemotherapy CA27.29 assessment

Genetic Alterations, Therapy Response, and Survival Among Patients With Triple-Negative Breast Cancer: A Secondary Analysis of a Randomized Clinical Trial

Importance: Subgroup definitions for possible deescalation of neoadjuvant cancer treatment are urgently needed in clinical practice. Objective: To investigate the effect of BRCA1 and/or BRCA2 tumor pathogenic variants (tPVs) by comparing 2 deescalated neoadjuvant regimens (nab-paclitaxel plus either carboplatin or gemcitabine) on pathologic complete response (pCR), invasive disease-free survival (IDFS), and overall survival (OS) of patients with early-stage triple-negative breast cancer (TNBC). Design, Setting, and Participants: This was a preplanned secondary analysis of a phase 2 prospective randomized clinical trial (ADAPT-TN) conducted by the West German Study Group (WSG) at 45 sites in Germany between June 2013 and February 2015. The trial enrolled patients with noninflammatory early-stage TNBC (clinical tumor size ≥1 cm; estrogen receptor and progesterone receptor expression <1%; and ERBB2 negative). DNA samples from pretreatment biopsies were obtained. Genetic analysis was performed between January 2018 and March 2020. Final data analyses took place in September 2023. Exposure: Patients were randomized to 12 weeks of treatment with nab-paclitaxel plus either carboplatin or gemcitabine; omission of otherwise mandatory anthracycline-containing chemotherapy was allowed in the case of pCR. tPVs in 20 cancer-associated genes, including BRCA1 and BRCA2, were analyzed using a customized gene panel. Main Outcomes and Measures: The prevalence of BRCA1 and/or BRCA2 tPVs and their effect on pCR rate, IDFS, and OS were evaluated using logistic and Cox proportional hazards regression. Results: Of the 307 patients with DNA samples from pretreatment biopsies available, tumor next-generation sequencing analyses were successful for 266 patients. The 266 patients included in this analysis were female, with a median age of 51 years (range, 26-76 years). A total of 162 patients (60.9%) had a clinical tumor size of 2 cm or greater, and 70 (26.3%) had clinical node-positive disease. BRCA1 and/or BRCA2 tPVs were detected in 42 patients (15.8%). The highest pCR rate among patients with BRCA1 and/or BRCA2 tPVs was seen in the nab-paclitaxel plus carboplatin group (9 of 14 patients [64.3%]) compared with the nab-paclitaxel plus gemcitabine group (10 of 28 [35.7%]) (odds ratio, 3.24 [95% CI, 0.85-12.36]; P = .08); the highest numeric 5-year IDFS and OS rates (84.4% and 92.9%, respectively) were seen in the nab-paclitaxel plus carboplatin group. Conclusions and Relevance: In this secondary analysis of the WSG-ADAPT-TN randomized clinical trial on tPVs, deescalated nab-paclitaxel plus carboplatin was superior to nab-paclitaxel plus gemcitabine, particularly in patients with BRCA1 and/or BRCA2 tPVs. These findings suggest that BRCA1 and/or BRCA2 tPV status could be a candidate marker for a deescalation strategy in early-stage TNBC; however, prospective validation of survival outcomes in larger cohorts with differentiation between germline and somatic pathogenic variants is necessary. Trial Registration: ClinicalTrials.gov Identifier: NCT01815242

Gemcitabine as adjuvant chemotherapy in patients with high-risk early breast cancer—results from the randomized phase III SUCCESS-A trial

Background When chemotherapy is indicated in patients with early breast cancer, regimens that contain anthracyclines and taxanes are established standard treatments. Gemcitabine has shown promising effects on the response and prognosis in patients with metastatic breast cancer. The SUCCESS-A trial (NCT02181101) examined the addition of gemcitabine to a standard chemotherapy regimen in high-risk early breast cancer patients. Methods A total of 3754 patients with at least one of the following characteristics were randomly assigned to one of the two treatment arms: nodal positivity, tumor grade 3, age ≤ 35 years, tumor larger than 2 cm, or negative hormone receptor status. The treatment arms received either three cycles of 5-fluorouracil, epirubicin, and cyclophosphamide, followed by three cycles of docetaxel (FEC → Doc); or three cycles of FEC followed by three cycles of docetaxel and gemcitabine (FEC → Doc/Gem). The primary study aim was disease-free survival (DFS), and the main secondary objectives were overall survival (OS) and safety. Results No differences were observed in the 5-year DFS or OS between FEC → Doc and FEC → Doc/Gem. The hazard ratio was 0.93 (95% CI, 0.78 to 1.12; P = 0.47) for DFS and 0.94 (95% CI, 0.74 to 1.19; P = 0.60) for OS. For patients treated with FEC → Doc and FEC → Doc/Gem, the 5-year probabilities of DFS were 86.6% and 87.2%, and the 5-year probabilities of OS were 92.8% and 92.5%, respectively. Conclusion Adding gemcitabine to a standard chemotherapy does not improve the outcomes in patients with high-risk early breast cancer and should therefore not be included in the adjuvant treatment setting

Abstract OT3-2-04: ADAPT - Adjuvant Dynamic marker-Adjusted Personalized Therapy trial optimizing risk assessment and therapy response prediction in early breast cancer

Abstract Background: Early therapy response is currently not regarded for further treatment decisions as standard of care in the treatment of breast cancer (BC). Predictive markers for the success of a certain therapy could support the physician’s choice of adequate and beneficial therapies by simultaneous reduction of unnecessary toxicity. Proliferation makers as Ki-67 seem to be a suitable tool, as dynamic changes of proliferation (as result of induction therapy) have been shown to be most important for outcome of neoadjuvant chemotherapy prediction in patients with pCR in distinct BC subtypes (luminal B, TNBC, HER2+). Methods: Trial design: ADAPT combines early assessment of prognosis by conventional markers (e.g. molecular classification, nodal status) with dynamic measurement of proliferation changes during a 3-week induction therapy, using baseline diagnostic core biopsy and a second biopsy after induction therapy. ADAPT consists of an umbrella trial and five different sub-trials (HR+/HER2-, HR+/HER2+, HR-/HER2+, HR-/HER2-, Elderly) and is set up as prospective, multi-center, controlled, non-blinded, randomized phase II/III trial. Subtype-specific treatment across the sub-trials is highly innovative and involves the following treatment strategies: • HR+/HER2-: endocrine therapy (ET) vs. chemotherapy (4xPac q2w – 4xEC q2w vs. 8xNab-Pac q1w – 4xEC q2w) + ET, depending on risk classification/early response. • HER2+/HR+: T-DM1 vs. T-DM1 + ET vs. trastuzumab + ET. • HER2+/HR-: Trastuzumab + Pertzumab ± Paclitaxel q1w. • TN: Nab-Paclitaxel + Gemcitabine vs. nab-Pac + Carboplatin. • Elderly: 2xMyocet + Cyclophosphamide q3w, depending on cPR/cCR or NC/toxicity the treatment will be continued for two more cycles or changed to 6xPac q1w. Adaptation/change in therapy regimens can be made by interim analysis after n=130 in each sub-trial. Eligibility criteria: Histologically confirmed unilateral primary invasive BC with known HR-/HER2-status (central pathology) for allocation to the respective sub-trial. Pts requiring chemo- or targeted (anti-HER2) therapy must have adequate laboratory values and organ function and must have no contraindications for the planned treatment. Primary endpoints: Evaluation of dynamic test for outcome prediction/prospective comparison of 5yr EFS in responders (intermediate risk (RS 12-25) / good response to short-term ET in HR+/HER2- or pts with pCR in HER2+/TN BC) compared to low risk HR+/HER2- (RS≤11, N0-1) pts (control group). Statistical methods: Assumption across sub-protocols: adjuvant CTx can be spared in HR+/HER2- or pCR be achieved in HER2+/TN in expected 1120 (HR+/HER2-) or 170 (HER2+/TN) pts, respectively. Outcome will be compared to the control group (expected n=640 HR+/HER2- pts: low risk (by RS), i.e. no CTx). Assuming 94% 5yr survival in control group, one-sided test of non-inferiority at 95% CI will have 80% power for survival non-inferiority margin of 3.2% (i.e. 90.8% survival). Present and target accrual: By June 2014, 73 active sites have recruited 1820 pts for ADAPT HR+/HER2-. Target accrual is 4000 pts. 190 of 380 pts were successfully randomized for ADAPT HER2+/HR+. ADAPT HER2+/HR- has included 17 of 220 pts and ADAPT Triple Negative has recruited 150 of 336 pts. Citation Format: Ulrike Nitz, Oleg Gluz, Raquel von Schumann, Daniel Hofmann, Ronald E Kates, Sherko Kuemmel, Michael Braun, Claudia Schumacher, Benno Nuding, Bahriye Aktas, Helmut Forstbauer, Nicolai Maass, Mahdi Rezai, Stefan Kraemer, Mathias Warm, Rachel Wuerstlein, Nadia Harbeck. ADAPT - Adjuvant Dynamic marker-Adjusted Personalized Therapy trial optimizing risk assessment and therapy response prediction in early breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr OT3-2-04.</jats:p