Radiotherapy statements of the 18th St. Gallen International Breast Cancer Consensus Conference-a German expert perspective

PURPOSE

To summarize the radiotherapy-relevant statements of the 18th St. Gallen Breast Cancer Consensus Conference and interpret the findings in light of German guideline recommendations.

METHODS

Statements and voting results from the 18th St. Gallen International Breast Cancer Consensus Conference were collected and analyzed according to their relevance for the radiation oncology community. The voting results were discussed in two hybrid meetings among the authors of this manuscript on March 18 and 19, 2023, in light of the German S3 guideline and the 2023 version of the Arbeitsgemeinschaft Gynäkologische Onkologie (AGO) guidelines.

RESULTS AND CONCLUSION

There was a high level of agreement between the radiotherapy-related statements of the 18th St. Gallen International Breast Cancer Consensus Conference and the German S3 and AGO guidelines. Discrepancies include the impact of number of lymph node metastases for the indication for postmastectomy radiotherapy.

Ratios of monocytes and neutrophils to lymphocytes in the blood predict benefit of CDK4/6 inhibitor treatment in metastatic breast cancer

Biomarkers to identify metastatic breast cancer (mBC) patients resistant to CDK4/6 inhibition (CDK4/6i) are currently missing. We evaluated the usefulness of the monocyte-to-lymphocyte ratio (MLR), the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) as predictive markers for de novo resistance to CDK4/6i. Various blood cell counts and MLR, NLR, PLR were recorded before treatment initiation (baseline) and four weeks later from 97 mBC patients receiving endocrine therapy (ET) alone or in combination with CDK4/6i. Binary blood cell count/ratios (mean = cut-off) were related to outcome using Cox regression. High MLR (p = 0.001) and high NLR (p = 0.01) at baseline significantly correlated with a shorter progression-free survival (PFS) in the CDK4/6i cohort, independent of any other clinical parameter as determined by multivariate Cox regression. Both, high MLR (p = 0.008) and high NLR (p = 0.043) as well as a decrease in PLR after four weeks of CDK4/6i first line treatment (p = 0.01) indicated a shorter overall survival. Moreover, decreasing PLR (p = 0.043) and increasing mean corpuscular volume (MCV; p = 0.011) within the first cycle of CDK4/6i correlated with a shorter PFS and decreasing MLR (p = 0.039) within the first cycle of first-line CDK4/6i was also correlated with shorter PFS. In summary, easily assessable blood cell parameter were shown to have predictive, monitoring and prognostic value and thus, could, in future, be used for individualized CDK4/6i therapy management. Most importantly, the imbalance of NLR and MLR at baseline might serve as predictive marker for de novo resistance to CDK4/6i in mBC patients.

Applicability of magnetic seeds for target lymph node biopsy after neoadjuvant chemotherapy in initially node-positive breast cancer patients: data from the AXSANA study

PURPOSE

Currently, various techniques are available to mark and selectively remove initially suspicious axillary lymph nodes (target lymph nodes, TLNs) in breast cancer patients receiving neoadjuvant chemotherapy (NACT). To date, limited data are available on whether the use of magnetic seeds (MS) is suitable for localizing TLNs. This study aimed to investigate the feasibility of MS in patients undergoing target lymph node biopsy (TLNB) or targeted axillary dissection (TAD) after NACT.

METHODS

Prospective data from the ongoing multicentric AXSANA study were extracted from selected patients in whom the TLN had been marked with an MS before NACT and who were enrolled from June 2020 to June 2023. The endpoints of the analysis were the detection rate, the rate of lost markers, and the potential impairment on magnetic resonance imaging (MRI) assessment.

RESULTS

In 187 patients from 27 study sites in seven countries, MS were placed into the TLN before NACT. In 151 of these, post-NACT surgery had been completed at the time of analysis. In 146 patients (96.0%), a TLN could successfully be detected. In three patients, the seed was removed but no lymphoid tissue was detected on histopathology. The rate of lost markers was 1.2% (2 out of 164 MS). In 15 out of 151 patients (9.9%), MRI assessment was reported to be compromised by MS placement.

CONCLUSION

MS show excellent applicability for TLNB/TAD when inserted before NACT with a high DR and a low rate of lost markers. Axillary MS can impair MRI assessment of the breast.

TRIAL REGISTRATION NUMBER

NCT04373655 (date of registration May 4, 2020).

Treatment of Early Breast Cancer: The 18th St. Gallen International Breast Cancer Consensus Conference against the Background of Current German Treatment Recommendations

This year's 18th St. Gallen (SG) consensus conference on the treatment of early breast cancer (SGBCC: St. Gallen International Breast Cancer Conference) focused on practice-oriented questions. The individual situation and risk-benefit assessment were discussed in great detail. As in previous years, a German working group of leading breast cancer experts presented the results of the international SGBCC 2023 against the background of German treatment recommendations - especially the updated treatment recommendations of the Arbeitsgemeinschaft Gynäkologische Onkologie e. V. (AGO) - for everyday clinical practice in Germany. The German treatment recommendations of AGO are based on the current evidence. The comparison with the clinical approach in Germany has proven useful, as the SGBCC panel consists of experts from different countries and disciplines. That is why country-specific characteristics can be incorporated into the SGBCC recommendations.

Update Breast Cancer 2023 Part 3 - Expert Opinions of Early Stage Breast Cancer Therapies

The St. Gallen (SG) International Breast Cancer Conference is held every two years, previously in St. Gallen and now in Vienna. This year (2023) marks the eighteenth edition of this conference, which focuses on the treatment of patients with early-stage breast carcinoma. A panel discussion will be held at the end of this four-day event, during which a panel of experts will give their opinions on current controversial issues relating to the treatment of early-stage breast cancer patients. To this end, questions are generally formulated in such a way that clinically realistic cases are presented - often including poignant hypothetical modifications. This review reports on the outcome of these discussions and summarises the data associated with individual questions raised.

Update Breast Cancer 2023 Part 2 - Advanced-Stage Breast Cancer

In recent years, a number of new therapies have led to advances in the treatment of patients with advanced breast carcinoma. These substances are mainly CDK4/6 inhibitors and other substances that can overcome endocrine resistance, oral selective estrogen receptor degraders, antibody drug conjugates (ADCs), and PARP inhibitors. This review summarizes and evaluates the latest study results that have been published in recent months. This includes the overall survival data of the Destiny-Breast03 study, the first analysis of the CAPItello-291 study, the comparison of CDK4/6 inhibitor treatment with chemotherapy in the first line of therapy (RIGHT Choice study), the first analysis of the Destiny-Breast02 study in the treatment setting after T-DM1 treatment, and the first analysis of the Serena-2 study. Most of these studies have the potential to significantly change the therapeutic landscape for patients with advanced breast carcinoma and show that the continued rapid development of new therapies is always producing new results.

Update Breast Cancer 2023 Part 1 - Early Stage Breast Cancer

With abemaciclib (monarchE study) and olaparib (OlympiA study) gaining approval in the adjuvant treatment setting, a significant change in the standard of care for patients with early stage breast cancer has been established for some time now. Accordingly, some diverse developments are slowly being transferred from the metastatic to the adjuvant treatment setting. Recently, there have also been positive reports of the NATALEE study. Other clinical studies are currently investigating substances that are already established in the metastatic setting. These include, for example, the DESTINY Breast05 study with trastuzumab deruxtecan and the SASCIA study with sacituzumab govitecan. In this review paper, we summarize and place in context the latest developments over the past months.

Systemic Therapy of Premenopausal Patients with Early Stage Hormone Receptor-Positive, HER2-Negative Breast Cancer - Controversies and Standards in Healthcare

In patients with existing ovarian function, there are some special aspects to adjuvant endocrine therapy in premenopausal patients with hormone receptor-positive, HER2-negative (HR pos./HER2 neg.) breast cancer. Treatment options include tamoxifen with or without a GnRH analog, and aromatase inhibitors with a GnRH analog. Furthermore, ovarian function is affected by previous chemotherapy. Both aromatase inhibitors (+GnRH analogs) and GnRH analogs in combination with tamoxifen are supposed to be indicated for patients at increased risk of recurrence. However, national and international guidelines and therapy recommendations do not provide a clear definition of intermediate or high risk; as a result, therapy decisions are often made for each patient on an individual basis. This is also reflected in the considerable variability at national and international levels, e.g., with regard to the use of aromatase inhibitors + GnRH analogs. This review summarizes the data on completed studies (e.g., SOFT, TEXT, EBCTCG meta-analyses) and the current multigene testing studies (TailorX, RxPonder, ADAPT), discusses the rationale for current studies (e.g., CLEAR-B), and looks ahead to future questions.

Abstract 2140: DNA damage response in circulating tumor cells shows predictive value for metastatic breast cancer patients receiving CDK4/6 inhibitors

Background: Resistance to CDK4/6 inhibitors (CDK4/6i), like Palbociclib and Ribociclib, plus endocrine therapy (TX) is an omnipresent topic for metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients (pts). Circulating tumor cells (CTCs) represent the oncogenic heterogeneity in real time. Here, we aim to identify markers of resistance to CDK4/6i by mRNA profiling of CTCs.

Methods: Blood of 90 HR+/HER2-MBC pts drawn before CDK4/6i plus endocrine TX (baseline: n=57 pts first line; n=33 second or more line pts), 19 HR+/HER2-MBC pts receiving endocrine monoTX (control group) and matched samples of 78/62 of these 109 pts after six months of TX/at progression (PD) were analyzed. Isolation of CTCs was conducted using the AdnaTest EMT2/StemCell Select. Expression profiling was conducted with preamplified cDNA utilizing QuantiNova LNA Probe assays targeting 25 genes. qPCR data were normalized to CD45 and data of 20 healthy female donors. Consumables: QIAGEN, Germany. Only results with Benjamini Hochberg corrected p<0.05 in univariate Cox regression and multivariate Cox regression with non-adjusted p<0.05 are demonstrated.

Results: At baseline, in pts treated with CDK4/6i in the first line, CETN2 (HR 3.6)/MLH3 (HR 4)/E2F1 (HR 5.3) overexpression signals in CTCs correlated significantly with shorter progression-free survival (PFS) and shorter overall survival [(baseline to death, OS) (HR 8.3/HR 4.9/HR 3.8)], whereas ESR1 signals correlated with a shorter OS (HR 4.4). After six months of TX, in CDK4/6i treated pts, CXCR4 and CETN2 signals correlated with a shorter PFS and the signal dynamics from baseline to six months of CXCR4, CETN2 and PCNA also correlated with a shorter PFS. At PD, STAT1 signals were identified as potential Ribociclib specific resistance markers and Hippo pathway inhibition as a potential new approach for postCDK4/6i TX, because TEAD2 and WWTR1 correlated with shorter remaining time to death.

Conclusion: We identified overexpression of transcripts involved in DNA damage response mechanisms (CETN2, MLH3 and/or PCNA) at baseline to have predictive and/or prognostic value in first line CDK4/6i treated pts while signal dynamics of CETN2 and PCNA to six months of TX could serve as monitoring marker in these pts. Currently, further longitudinal blood sampling over the course of treatment is underway to give a deeper insight in resistance development under CDK4/6i treatment.

Citation Format: Corinna Keup, Charlotte Gruber, Stefanos Ioannis Moukas, Mitra Tewes, Hans-Christian Kolberg, Rainer Kimmig, Sabine Kasimir-Bauer. DNA damage response in circulating tumor cells shows predictive value for metastatic breast cancer patients receiving CDK4/6 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2140.

Abstract P2-14-01: MOLECULAR FLUORESCENCE-GUIDED SURGERY USING BEVA800 FOR THE ASSESSMENT OF TUMOR MARGINS DURING BREAST CONSERVING SURGERY OF PATIENTS WITH PRIMARY BREAST CANCER (MARGIN-II)

Introduction: The goal of breast conserving surgery (BCS) for early breast cancer (EBC) is to remove the tumor in toto and preserving as much of the normal breast tissue as possible. In 20-50% of cases a re-excision is necessary because of involved margins. Repeat surgeries are not only a burden to patients physically but also psychologically and can delay recommended adjuvant therapies. Accurate determination of tumor margins during surgery is therefore a critical need. Breast cancer tissue produces significantly higher amounts of VEGF-A than healthy tissue. VEGF-A stimulates tumor angiogenesis and is therefore a target for molecular imaging techniques. The fluorescence imaging agent bevacizumab-IRDye800CW (Beva800) is a conjugate of bevacizumab and IRDye800CW and binds specifically to VEGF-A. Beva800 provides a potentially efficacious approach to imaging specimen and cavity margins during BCS. We are presenting a phase II study that combined Beva800 with the SurgVision Explorer Air camera for intraoperative margin assessment during BCS for EBC. Methods: MARGIN II is a multicenter open-label single arm prospective clinical trial aimed at evaluating Beva800 for assessment of tumor margins in women with EBC scheduled for BCS. The study was a within-patient comparison of positive tumor margin rates using BCS standard of care margin assessment compared to intraoperative assessment with 4.5 mg Beva800 and fluorescence imaging with the SurgVision Explorer Air camera. All patients received an i.-v. bolus injection of 4.5 mg of Beva800 three days before surgery. The fluorescent signal was visualized during surgery using NIR fluorescence imaging (700–1000 nm). Standard of care margin assessment was defined as visual inspection, palpation and, in cases of pre-operative wire marking, specimen sonography or mammography. Beva800 efficacy was determined as the number of patients in which a pathology-confirmed positive margin was identified by fluorescence-guided surgery using Beva800 but not by standard of care BCS. Results: 49 patients were included in 5 centers. 4 training cases were only included in the safety analysis, 45 patients were evaluable for the efficacy analysis. 8 patients (17.8%) had involved margins after standard of care BCS, 4 of which were detected by molecular fluorescence intraoperatively resulting in the reduction of patients with positive margins by 50% (95% CI: 15.7%, 84.3%). 4 patients (8.9%; 95% CI: 2.5%, 21.1%) needed a re-excision because of involved margins. In 27 patients (60.0%) the additional molecular fluorescence guided cavity shaving did not change the resection status from positive to negative (false positive). Adverse events were reported by 16 of 49 patients (32.7%), but only 3 (6.1%) were related to Beva800 (syncope, hot flush, hypertensive crisis). One patient experienced a treatment related SAE (hypertensive crisis). No anti-Beva800 antibodies were detected. Conclusion: In our analysis the rate of necessary second operations was reduced by 50% using Beva800 and the SurgVision Explorer Air camera. The safety analysis confirmed the positive safety profile of Beva800 found in previous studies. Molecular fluorescence-guided surgery may have the potential to change the practice of breast conserving surgery by reducing unnecessary re-excisions. Future studies will have to address the high false positive rates.

Citation Format: Hans-Christian Kolberg, Carmen Röhm, Angrit Stachs, Florian Schütz, Jens-Uwe Blohmer, Sarah Wetzig, Steffi Hartmann, Jörg Heil, Markus Hahn. MOLECULAR FLUORESCENCE-GUIDED SURGERY USING BEVA800 FOR THE ASSESSMENT OF TUMOR MARGINS DURING BREAST CONSERVING SURGERY OF PATIENTS WITH PRIMARY BREAST CANCER (MARGIN-II) [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 P2-14-01.

Update Breast Cancer 2022 Part 5 - Early Stage Breast Cancer

The treatment of patients with early stage breast cancer has changed in recent years due to the introduction of pembrolizumab, olaparib, and abemaciclib. These and other drugs with the same class of active ingredient are currently in trial for various indications. This review article summarizes the latest results that have either been presented at major conferences such as the ESMO 2022 or published recently in international journals. This includes reports on newly discovered breast cancer genes, atezolizumab in neoadjuvant therapy in HER2-positive patients, long-term data from the APHINITY study, and on how preoperative peritumoral application of local anesthetics can influence the prognosis. We also present solid data on dynamic Ki-67 from the ADAPT studies.

Update Breast Cancer 2022 Part 6 - Advanced-Stage Breast Cancer

Large-scale study programs on CDK4/6 inhibitors, targeted therapies, and antibody-drug conjugates launched in recent years have yielded results from current studies which are now being published in journals and presented at international conferences. In this context, new results are available from the major CDK4/6 inhibitor studies. Also, an increasing amount of data is being published from large-scale genomic studies on efficacy and resistance mechanisms in patients treated with CDK4/6 inhibitors. These results now form the basis for further research plans to investigate combination therapies and treatment sequencing. Based on the latest published results, sacituzumab govitecan is now available as a second antibody-drug conjugate; this brings an advantage in terms of overall survival for patients with hormone receptor-positive (HRpos)/HER2-negative (HER2neg) breast cancer. In this review article, we summarize the latest developments and place them in context according to the current status of research.

Abstract PD11-03: PD11-03 Comparison of a mono Atezolizumab window followed by Atezolizumab and chemotherapy with Atezolizumab and chemotherapy in triple negative breast cancer – an interim analysis of the adaptive randomized neoadjuvant trial NeoMono

Introduction: Improvement of systemic treatment of TNBC represents an unmet medical need. Targeted therapy of regulatory immune pathways has become an important option in the treatment of many malignant diseases including breast cancer. Neodjuvant trials combining chemotherapy and checkpoint inhibitors (KEYNOTE-522 and IMpassion031) have demonstrated a meaningful benefit regarding pathological complete remission (pCR) for the addition of PD-1- or PD-L1-inhibitors to chemotherapy in patients with TNBC. In the KEYNOTE-522 trial, the addition of an immune checkpoint inhibitor (ICI) to neoadjuvant chemotherapy also had a beneficial impact on event-free survival even in patients who did not achieve a pCR. Of note, in the neoadjuvant GeparNuevo trial only those patients with TNBC who received a 2-week checkpoint inhibitor monotherapy window before the start of neoadjuvant chemotherapy in combination with checkpoint inhibition, achieved a significant pCR benefit from the addition of the PD-1 inhibitor Durvalumab to neoadjuvant chemotherapy alone. Methods: NeoMono is a phase 2 randomized multicenter trial recruiting male and female patients with primary TNBC (defined as ER/PR < 10% and HER2 negative). Neoadjuvant treatment in Arm A and B consists of Atezolizumab 1200 mg every 3 weeks in addition to neoadjuvant chemotherapy (i.e., 12 x Carboplatin and Paclitaxel q1w followed by Epirubicin and Cyclophosphamide q3w). Combination therapy in arm A is preceded by an Atezolizumab monotherapy window (i.e., 840 mg Atezolizumab once two weeks prior to initiation of combination therapy). Study goals are to compare the efficacy of neoadjuvant chemotherapy with Atezolizumab with and without an Atezolizumab two-week monotherapy window (primary endpoint: pCR) and the identification of biomarkers predicting (early) response to or resistance against Atezolizumab. The extensive translational program of the neoMono trial aims at identifying these biomarkers on tumor and patient level through analysis of sequential tissue and liquid biopsies. The NeoMono statistical design adapts the idea of a proof-of-concept trial and uses Bayesian posterior and predictive probabilities for inference about the primary hypothesis. Up to four planned efficacy interim analyses provide decision points for early stopping for success or futility. The expected maximum number of patients to be recruited is 458. Results: The predefined number of 50 patients in each arm being evaluable for the primary endpoint pCR has been reached and the results of the first planned interim analysis will be presented at the meeting. Conclusion: The addition of an ICI to state of the art neoadjuvant chemotherapy has recently been established as a new standard of care in TNBC. NeoMono has the potential to answer the question if the beneficial effect of the ICI can be increased by a chemotherapy free ICI monotherapy window prior to a combination with neoadjuvant chemotherapy.

Citation Format: Hans-Christian Kolberg, Johannes Schumacher, Ramona Erber, Michael Braun, Bernhard Heinrich, Oliver Hoffmann, Peter A. Fasching, Georg Kunz, Michael P. Lux, Christian Schem, Eva-Maria Grischke, Mustafa Deryal, Kristina Lübbe, Arndt Hartmann, Sabine Kasimir-Bauer, Cornelia Kolberg-Liedtke. PD11-03 Comparison of a mono Atezolizumab window followed by Atezolizumab and chemotherapy with Atezolizumab and chemotherapy in triple negative breast cancer – an interim analysis of the adaptive randomized neoadjuvant trial NeoMono [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 PD11-03.

Abstract OT1-03-06: Phase 1b/2 study of ladiratuzumab vedotin (LV) in combination with pembrolizumab for first-line treatment of triple-negative breast cancer (SGNLVA-002, trial in progress)

Background Patients with metastatic triple-negative breast cancer (mTNBC) have a poor prognosis. Treatment combinations of anti-programmed death protein 1 (anti–PD-1) agents with chemotherapy have shown promise in mTNBC. Ladiratuzumab vedotin (LV) is an investigational antibody-drug conjugate directed to LIV-1, a protein highly expressed on breast cancer cells, via a humanized IgG1 monoclonal antibody conjugated to approximately 4 molecules of monomethyl auristatin E (MMAE) by a protease-cleavable linker. LIV-1–mediated delivery of MMAE disrupts microtubules and induces cell cycle arrest and apoptosis. LV has also been shown to drive immunogenic cell death (ICD) to elicit an immune response. LV + pembrolizumab may result in synergistic activity through LV-induced ICD, creating a microenvironment favorable for enhanced anti–PD-1 activity. Interim results from an ongoing, multi-part, open-label study investigating the safety and efficacy of LV in patients with metastatic breast cancer (SGNLVA-001, NCT01969643), showed weekly LV monotherapy at doses up to 1.5 mg/kg were clinically active and generally well tolerated (Tsai 2021). Based on pharmacokinetic and pharmacodynamic modeling and simulation analysis, an intermittent LV + pembrolizumab dosing regimen is being evaluated to further enhance efficacy and improve the tolerability profile. Due to an unmet medical need for patients with unresectable locally advanced (LA)/mTNBC who are programmed death ligand 1 (PD-L1) low or negative, Part D will focus on this patient population. Trial Design SGNLVA-002 (NCT03310957) is an ongoing global single-arm, open-label phase 1b/2 study of LV + pembrolizumab as 1L therapy for patients with unresectable LA/mTNBC. Part D is currently enrolling ~40 patients. Eligible patients must have advanced disease with no prior cytotoxic/anti–PD-1 treatment, PD-L1 combined positive score < 10, measurable disease per RECIST v1.1, and an ECOG performance status ≤1. Patients with Grade ≥2 pre-existing neuropathy or active central nervous system metastases are not permitted. Patients will receive LV at 1.5 mg/kg on Days 1 and 8 every 21 days plus pembrolizumab 200 mg on Day 1 q3w. The primary objectives are to evaluate the safety/tolerability and objective response rate of LV + pembrolizumab. Secondary objectives include duration of response, disease control rate, progression-free survival, and overall survival. Safety and efficacy endpoints will be summarized with descriptive statistics. Global enrollment is ongoing in the US, EU, and Asia.

Citation Format: Patrick Dillon, Reva Basho, Hyo S. Han, Hans-Christian Kolberg, Katherine Tkaczuk, George Zahrah, Maria Gion, Herman Voss, Jane Meisel, Timothy Pluard, Jenny Fox, Mafalda Oliveira, Ursa Brown-Glaberman, Erica Stringer-Reasor, Luis Manso, Sherko Küemmel, Lin Chi Chen, Sheng Wu, Brandon Croft, Valentina Boni. Phase 1b/2 study of ladiratuzumab vedotin (LV) in combination with pembrolizumab for first-line treatment of triple-negative breast cancer (SGNLVA-002, trial in progress) [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 OT1-03-06.

Abstract P5-02-25: Transcriptional profiling of CTCs in metastatic breast cancer patients in the course of CDK4/6 inhibition

Background: De novo resistance defined as progression within six months and acquired resistance are one of the major problems in the subset of metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients without visceral crisis receiving CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy (TX). Here, we aim to identify predictive and monitoring markers of CDK4/6i resistance by conducting transcriptional profiling of circulating tumor cells (CTCs) that represent a real-time snapshot of the heterogeneity. Methods: Blood of (A) 60 HR+/HER2- MBC patients drawn at baseline of Palbociclib plus endocrine TX (TX as first line n=31, second or more lines n=29), (B) 19 HR+/HER2- MBC patients drawn before the initiation of endocrine monoTX (control) and matched blood samples of these patients after six months under TX (n=72) and at the time of progression (n=42) were analyzed. To enlarge the global CDK4/6i cohort at baseline, blood of (C) 32 patients before the initiation of Ribociclib plus endocrine TX was also drawn. Patients with progression within six months were defined as non-responders. Isolation of CTCs was conducted using positive immunomagnetic selection (AdnaTest EMT2/StemCell Select) and preamplified cDNA was analyzed by a multimarker qPCR panel utilizing QuantiNova LNA Probe assays targeting 25 genes involved in the DNA damage -, MAPK -, STAT -, Hippo – pathway or cell cycle, chemokine sensing, multidrug resistance and cell adhesion. qPCR data was normalized to CD45 and data of 20 healthy female donor controls to identify BC CTC specific overexpression signals with a specificity of >90% for all targets. Consumables: QIAGEN, Germany. Statistical analysis included log-rank testing and univariate Cox regression. Results: For first line CDK4/6i treated patients at baseline, CETN2 and E2F1 signals correlated significantly with worse progression-free survival (PFS) while CETN2 signals also related significantly to non-response. Furthermore, CETN2 and PCNA signals were significantly associated with worse overall survival (OS). Analyzing the Palbociclib cohort after six months of TX, PCNA signals correlated significantly with a decreased PFS while EpCAM signals showed a significant association with OS. In addition, CETN2, CXCR4, EpCAM, MLH3, WWTR1 signals after six months were shown to correlate significantly with a decreased OS and PFS and MAPK1 signals were only found in the non-responders. While non-response was related to appearing (from baseline to six months under TX) ABCC2, JUN and MAPK1 signals, disappearing ABCC2 signals were only found in the responders. Dynamics of ABCC2, CXCR4, EpCAM, JUN, MAPK1, MLH3, STAT1 and WWTR1 signals from baseline to six months under TX correlated significantly with OS and CXCR4 signal dynamics significantly with a worse PFS. At the time of progression, the presence of E2F1, JUN, MAPK1 and STAT1 signals correlated significantly with a decreased OS and in comparison to baseline analysis, the prevalence of ABCC2, EpCAM, E2F1, CETN2 and CXCR4 signals increased. Conclusion: CTC overexpression signals at baseline of targets involved in the cell cycle (CETN2 and E2F1) might be predictive markers for de novo resistance to CDK4/6i as first line TX, while ABCC2 (multidrug resistance), EpCAM (cell adhesion), E2F1, CETN2 and CXCR4 (chemokine sensing) signals could indicate acquired resistance to Palbociclib. In case of disease progression, E2F1, JUN (cell cycle) and targets of the MAPK- and STAT- pathway could be relevant targets for therapeutic strategies beyond Palbociclib TX. Monitoring and prognostic value was shown for single and repeated measurement of signals under TX in genes involved in resistance, cell cycle progression, DNA damage response (MLH3, PCNA), chemokine sensing, cell adhesion and the MAPK-, STAT- and Hippo (WWTR1) pathway.

Citation Format: Sabine Kasimir-Bauer, Charlotte Gruber, Stefanos Moukas, Mitra Tewes, Hans-Christian Kolberg, Rainer Kimmig, Corinna Keup. Transcriptional profiling of CTCs in metastatic breast cancer patients in the course of CDK4/6 inhibition [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 P5-02-25.

Breast Conserving Surgery in Combination With Targeted Intraoperative Radiotherapy Compared to Mastectomy for In-breast-tumor-recurrence

BACKGROUND/AIM

Mastectomy is the standard treatment of in-breast-recurrence of breast cancer after breast conserving surgery (BCS) and external beam radiation therapy (EBRT). In selected cases, it is possible to preserve the breast if targeted intraoperative radiotherapy (TARGIT-IORT) can be given during the second lumpectomy. This is a comparative analysis of overall survival and quality of life (QoL).

PATIENTS AND METHODS

Patients in our database with in-breast-recurrence and either mastectomy or BCS and TARGIT-IORT were included. Identified patients were offered participation in a prospective QoL-analysis using the BREAST-Q questionnaire. The cohorts were compared for confounding parameters, overall survival, and QoL.

RESULTS

Thirty-six patients treated for in-breast-recurrence were included, 21 had received a mastectomy and 16 patients had received BCS with TARGIT-IORT. Mean follow-up was 12.8 years since primary diagnosis and 4.2 years since recurrence. Both groups were balanced regarding prognostic parameters. Overall survival was numerically longer for BCS and TARGIT-IORT, but the numbers were too small for formal statistical analysis. No patient had further in-breast-recurrence. Psychosocial and sexual wellbeing did not differ between both groups. Physical wellbeing was significantly superior for those whose breast could be preserved (p-value=0.021). Patient-reported incidence and severity of lymphedema of the arm was significantly worse in the mastectomy group (p=0.007).

CONCLUSION

Preserving the breast by use of TARGIT-IORT was safe with no re-recurrence and no detriment to overall survival in our analysis and led to a statistically significant improvement in physical wellbeing and incidence of lymphedema. These data should increase the confidence in offering breast preservation after in-breast-recurrence of breast cancer.

Pembrolizumab in combination with nab-paclitaxel for the treatment of patients with early-stage triple-negative breast cancer - A single-arm phase II trial (NeoImmunoboost, AGO-B-041)

BACKGROUND

Pembrolizumab is approved for the neoadjuvant/adjuvant treatment of early triple-negative breast cancer (TNBC) patients in combination with chemotherapy. The Keynote-522 trial used platinum chemotherapy. As neoadjuvant nab-paclitaxel (nP) is also highly effective in triple-negative breast cancer patients, this study investigates the response to nP-containing neoadjuvant chemotherapy in combination with pembrolizumab.

PATIENTS AND METHODS

NeoImmunoboost (AGO-B-041/NCT03289819) is a multicenter, prospective single-arm phase II trial. Patients were treated with 12 weekly cycles of nP followed by four three-weekly cycles of epirubicin/cyclophosphamide. Pembrolizumab was given three-weekly in combination with these chemotherapies. The study was planned for 50 patients. After 25 patients, the study was amended to include a pre-chemotherapy single application of pembrolizumab. The primary aim was pathological complete response (pCR), and the secondary aims were safety and quality of life.

RESULTS

Of 50 included patients, 33 (66.0%; 95%confidence interval: 51.2%-78.8%) had a (ypT0/is ypN0) pCR. The pCR rate in the per-protocol population (n = 39) was 71.8% (95%confidence interval: 55.1%-85.0%). The most common adverse events of any grade were fatigue (58.5%), peripheral sensory neuropathy (54.7%) and neutropenia (52.8%). The pCR rate in the cohort of 27 patients with a pre-chemotherapy pembrolizumab dose was 59.3%, and 73.9% in the 23 patients without pre-chemotherapy dose.

CONCLUSIONS

pCR rates after NACT with nP and anthracycline combined with pembrolizumab are encouraging. With acceptable side-effect profiles, this treatment might be a reasonable alternative to platinum-containing chemotherapy in cases of contraindications. However, without data from randomised trials and long-term follow up, platinum/anthracycline/taxane-based chemotherapy remains the standard combination chemotherapy for pembrolizumab.

Return of individual genomic research results within the PRAEGNANT multicenter registry study

PURPOSE

The PRAEGNANT study is a registry study for metastatic breast cancer patients, focusing on biomarker detection. Recently, within this study, genetic alterations in 37 breast cancer predisposition genes were analyzed and genetic findings were detected for 396 participants. The aim of this project was to return genetic results to the physicians and to analyze actions taken (e.g., disclosure of results to patients, validation of results, clinical impact, and impact on the patient's quality of life) using a questionnaire.

METHODS

235 questionnaires were sent out to the study centers, with each questionnaire representing one patient with a genetic finding. The questionnaire consisted of twelve questions in the German language, referring to the disclosure of results, validation of test results, and their impact on treatment decisions and on the patient's quality of life.

RESULTS

135 (57.5%) questionnaires were completed. Of these, 46 (34.1%) stated that results were returned to the patients. In 80.0% (N = 36) of cases where results were returned, the patient had not been aware of the finding previously. For 27 patients (64.3%), genetic findings had not been validated beforehand. All validation procedures (N = 15) were covered by the patients' health insurance. For 11 (25.0%) patients, physicians reported that the research results influenced current or future decision-making on treatment, and for 37.8% (N = 17) the results influenced whether family members will be genetically tested.

CONCLUSION

This study provides novel insights into the return of research results and into clinical and personal benefits of disclosure of genetic findings within a German registry.

Update Breast Cancer 2022 Part 4 - Advanced-Stage Breast Cancer

For the treatment of patients with advanced HER2-negative hormone receptor-positive breast cancer, several substances have been introduced into practice in recent years. In addition, other drugs are under development. A number of studies have been published over the past year which have shown either an advantage for progression-free survival or for overall survival. This review summarizes the latest results, which have been published at current congresses or in specialist journals, and classifies them in the clinical treatment context. In particular, the importance of therapy with CDK4/6 inhibitors - trastuzumab deruxtecan, sacituzumab govitecan and capivasertib - is discussed. For trastuzumab deruxtecan, an overall survival benefit in HER2-negative breast cancer with low HER2 expression (HER2-low expression) was reported in the Destiny-Breast-04 study. Similarly, there was an overall survival benefit in the FAKTION study with capivasertib. The lack of overall survival benefit for palbociclib in the first line of therapy raises the question of clinical classification.

Axillary Staging after Neoadjuvant Chemotherapy for Initially Node-Positive Breast Carcinoma in Germany: Initial Data from the AXSANA study

Introduction To date, the optimal axillary staging procedure for initially node-positive breast carcinoma patients after neoadjuvant chemotherapy (NACT) has been unclear. The aim of the AXSANA study is to prospectively compare different surgical staging techniques with respect to the oncological outcome and quality of life for the patients. Little is known about current clinical practice in Germany. Material and Methods In this paper we analyzed data from patients enrolled in the AXSANA study at German study sites from June 2020 to March 2022. Results During the period under investigation, 1135 patients were recruited at 143 study sites. More than three suspicious lymph nodes were initially found in 22% of patients. The target lymph node (TLN) was marked in 64% of cases. This was done with clips/coils in 83% of patients, with magnetic seeds or carbon suspension in 8% each, and with a radar marker in 1% of patients. After NACT, targeted axillary dissection (TAD) or axillary lymphadenectomy (ALND) were each planned in 48% of patients, and sentinel lymph node biopsy alone (SLNB) in 2%. Clinically, the nodal status after NACT was found to be unremarkable in 65% of cases. Histological lymph node status was correctly assessed by palpation in 65% of patients and by sonography in 69% of patients. Conclusion At the German AXSANA study sites, TAD and ALND are currently used as the most common surgical staging procedures after NACT in initially node-positive breast cancer patients. The TLN is marked with various markers prior to NACT. Given the inadequate accuracy of clinical assessment of axillary lymph node status after NACT, it should be questioned whether axillary dissection after NACT should be performed based on clinical assessment of nodal status alone.

Update Breast Cancer 2022 Part 3 - Early-Stage Breast Cancer

This review summarizes recent developments in the prevention and treatment of patients with early-stage breast cancer. The individual disease risk for different molecular subtypes was investigated in a large epidemiological study. With regard to treatment, new data are available from long-term follow-up of the Aphinity study, as well as new data on neoadjuvant therapy with atezolizumab in HER2-positive patients. Biomarkers, such as residual cancer burden, were investigated in the context of pembrolizumab therapy. A Genomic Grade Index study in elderly patients is one of a group of studies investigating the use of modern multigene tests to identify patients with an excellent prognosis in whom chemotherapy may be avoided. These and other aspects of the latest developments in the diagnosis and treatment of breast cancer are described in this review.

The Role of C-Reactive Protein as a Prognostic Biomarker in Patients with Early Breast Cancer Treated with Neoadjuvant Chemotherapy

Background

C-reactive protein (CRP) is an acute phase reactant influenced by inflammation and tissue damage. Elevated CRP levels have been associated with poor outcome of various cancers including breast cancer. However, evidence regarding a potential impact of CRP levels on outcome of neoadjuvant chemotherapy (NACT) in patients with early breast cancer (EBC) is insufficient.

Methods

Patients who had received NACT for EBC and had available data regarding CRP levels before therapy, pathologic complete remission (pCR), and follow-up were included. The association between CRP at baseline and outcome parameters was analyzed.

Results

152 women were included in this analysis; median follow-up was 5.8 years. No association between CRP at baseline and pCR rates could be detected. 6.6% of the patients developed a local recurrence, 10.5% developed a distant recurrence, and 5.2% died from breast cancer. A negative correlation (Spearman-Rho) between CRP at baseline and overall survival (OS) (correlation coefficient (CC) -0.255; p = 0.45), disease-free survival (DFS) (CC -0.348; p = 0.075), local recurrence-free survival (LRFS) (CC -0.245; p = 0.327), and distant DFS (DDFS) (CC -0.422; p = 0.057) was not statistically significant, although especially in DFS and DDFS a strong trend was detected. The probability of death from breast cancer was 2% if the CRP was <0.08 mg/dL and 40% if the CRP was >2.08 mg/dL; this association was highly statistically significant (χ²; p < 0.001). These results were independent from age, estrogen and progesterone receptor status, HER2 status, nodal status, and grading. The hazard ratio for OS was 5.75 (p = 0.004) for CRP <0.08 mg/dL versus CRP >2.08 mg/dL.

Discussion/Conclusion

CRP at baseline is not predictive for pCR in EBC after NACT in our patient dataset. However, an association of parameters of long-term prognosis with CRP could be demonstrated. Although the correlations of higher CRP levels at baseline and shorter OS, DFS, LRFS, and DDFS were not significant, a strong trend could be detected that was reproduced in the analysis of different groups of CRP levels and the probability of breast cancer mortality. Higher CRP levels are indicating a worse prognosis in EBC after NACT in this retrospective analysis. These results justify further investigation of CRP not as a predictive parameter for pCR but as a biomarker of long-term prognosis in EBC in prospective trials and may lead to therapeutic approaches with the aim of lowering CRP levels.

Implementation of CDK4/6 Inhibitors and its Influence on the Treatment Landscape of Advanced Breast Cancer Patients - Data from the Real-World Registry PRAEGNANT

Background Comprehensive data from prospective clinical trials have led to a high level of evidence establishing CDK4/6 inhibitors in combination with endocrine treatment (CDK4/6i + ET) as a standard for the treatment of HER2-negative, hormone receptor-positive (HER2- HR+) breast cancer patients in the first-line advanced therapy setting. Data on patient populations that have been treated in the real-world setting may provide an insight into changes of patient characteristics and prognosis over time. Methods The data were extracted from the prospective real-world registry PRAEGNANT (NCT02338167). Patients had to have HER2- HR+ advanced breast cancer in the first-line metastatic setting. The chosen therapies were described as well as progression-free survival (PFS) and overall survival (OS) in relation to the given therapies and time periods during which they were indicated. Results CDK4/6 inhibitors have been rapidly implemented since their introduction in November 2016. In recent years (2018 - 2022), about 70 - 80% of the patient population have been treated with CDK4/6 inhibitors, while endocrine monotherapy was given to about 10% and chemotherapy to about 15% of all patients. The prognosis was worst in patients treated with chemotherapy. Recently, mainly patients with a good prognosis are being treated with endocrine monotherapy, and patients who are treated with chemotherapy have an unfavorable prognosis. The PFS and OS of patients treated with CDK4/6i + ET have remained similar over time despite changes in patient characteristics. Conclusion A treatment with CDK4/6i + ET has rapidly become the therapy standard for patients in the first-line advanced breast cancer setting. After the implementation of CDK4/6i + ET, endocrine monotherapy is only given to patients with a very favorable prognosis, while chemotherapy is provided to patients with a rather unfavorable prognosis. These changes in patient characteristics did not seem to influence the prognosis of patients treated with CDK4/6i + ET.

Occurrence and characteristics of patients with de novo advanced breast cancer according to patient and tumor characteristics - A retrospective analysis of a real world registry

BACKGROUND

Patients with de novo metastatic breast cancer (dnMBC) may have different clinical and pathological characteristics. In studies concerned with first-line metastatic patients, the proportion of these patients without secondary resistance mechanisms may have a large influence ont the study results. The aim of this study was to identify patient and tumor characteristics that are associated with dnMBC vs. recurrent MBC (rMBC).

METHODS

This is a retrospective analysis of data prospectively collected in the PRAEGNANT metastatic breast cancer registry (NCT02338167). Firs line treated patients were eligible. Patient and tumor characteristics were compared with common disease and tumor characteristics relative to de novo metastatic status, as well as early and late recurrences after primary disease without metastases.

RESULTS

Among the 947 patients identified, 355 were included with de novo metastatic disease (37.5%). Older age and HER2-positive disease were significantly associated with a higher frequency of dnMBC. Patients younger than 50, 50-69, or 70 years or older had dnMBC frequencies of 22.7%, 44.0%, and 57.6%, respectively. HER2-positive patients had dnMBC at initial presentation in 49.1% of cases, in comparison with 21.9%, 35.5%, and 37.6% in patients with triple-negative, luminal A-like and luminal B-like breast cancer, respectively.

CONCLUSION

Age and breast cancer subtype are associated with the frequency of first-line MBC patients. Inclusion criteria concerning age or breast cancer subtype can influence the frequency of these patients in a selected patient population and can therefore modify the number of patients with secondary resistance to specific therapies in clinical trials.

Update Breast Cancer 2022 Part 1 – Early Stage Breast Cancer

Evidence relating to the treatment of breast cancer patients with early-stage disease has increased significantly in the past year. Abemaciclib, olaparib, and pembrolizumab are new drugs with good efficacy in the relevant patient groups. However, some questions remain unanswered. In particular, it remains unclear which premenopausal patients with hormone receptor-positive breast cancer should be spared unnecessary treatment. The question of the degree to which chemotherapy exerts a direct cytotoxic effect on the tumor or reduces ovarian function through chemotherapy could be of key importance. This group of patients could potentially be spared chemotherapy. New, previously experimental biomarker analysis methods, such as spatial analysis of gene expression (spatial transcriptomics) are gradually finding their way into large randomized phase III trials, such as the NeoTRIP trial. This in turn leads to a better understanding of the predictive factors of new therapies, for example immunotherapy. This review summarizes the scientific innovations from recent congresses such as the San Antonio Breast Cancer Symposium 2021 but also from recent publications.

Update Breast Cancer 2022 Part 2 – Advanced Stage Breast Cancer

For patients with advanced breast cancer, several novel therapies have emerged in recent years, including CDK4/6 inhibitors, immune checkpoint inhibitors, PARP inhibitors, alpelisib, tucatinib and trastuzumab-deruxtecan, and sacituzumab-govitecan, which have transformed and expanded the therapeutic landscape for patients with advanced breast cancer. Some of these substances have now been approved for use in the early stages of the disease, or are expected to be approved in the near future, so the therapeutic landscape will change once again. Therefore, current scientific efforts are focused on the introduction of new substances and understanding their mechanisms of progression and efficacy. This review summarizes recent developments with reference to recent publications and conferences. Findings on the treatment of patients with HER2-positive breast cancer and brain metastases are presented, as are a number of studies looking at biomarkers in patients with HER2-negative, hormone receptor-positive breast cancer. In particular, the introduction of oral selective estrogen receptor degraders provides new opportunities to establish biomarker-based therapy. Molecular diagnostics is establishing itself as a diagnostic marker and parameter of progression.

Breast preservation after local recurrence of breast cancer: Comparison of length and quality of life (QoL) between breast conserving surgery with intraoperative radiotherapy (TARGIT-IORT) versus mastectomy

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Background: Mastectomy is the standard treatment of in-breast-recurrence of breast cancer after breast conserving surgery (BCS) and external beam radiation therapy (EBRT). In selected cases it is possible to preserve the breast if TARGIT-IORT can be given during the second lumpectomy. We present a comparative analysis of overall survival and QoL. Methods: We identified all patients who had local recurrence of breast cancer after BCS and EBRT in our prospectively maintained database. Patients were included if they had undergone either a mastectomy or BCS along with TARGIT-IORT. Patients with distant disease were excluded. Identified patients were contacted and offered participation in a prospective QoL-analysis using the BREAST-Q questionnaire. The cohorts were compared for confounding parameters, overall survival, psychosocial/physical/sexual wellbeing and satisfaction with the surgical result. Results: 36 patients treated for local recurrence were included in this analysis, 21 had received a mastectomy and 16 patients had chosen to preserve their breast and after due discussion, received BCS along with TARGIT-IORT. Mean follow-up was 12.8 years since primary diagnosis and 4.2 years since recurrence. There were no significant differences between both groups regarding age, ER, PR, HER2neu, tumor size or nodal status at primary diagnosis or at recurrence and the distribution of invasive versus non-invasive recurrences. 1 patient in the BCT and TARGIT-IORT group (6.7%) and 3 patients in the mastectomy group (14.3%) died during follow up. Overall survival was numerically longer for BCS and TARGIT-IORT either calculated from primary diagnosis (median 18 years versus 8 years) or from recurrence (median 5.1 years versus 3.2 years), but the numbers were too small for formal statistical analysis. No patient had further in-breast-recurrence of cancer. 12 patients in the mastectomy group and 10 patients in the BCS and IORT group returned the BREAST-Q questionnaire. Psychosocial wellbeing, sexual wellbeing and satisfaction with the surgeon did not differ between both groups. Physical wellbeing was significantly superior for those whose breast could be preserved (median score for BCS and TARGIT-IORT group was 91 (71-100) vs. 66 (14-100) for the mastectomy group, p-value = 0.021). Conclusions: Many patients who have local recurrence of breast cancer are reluctant to lose their breast. We found that preserving the breast by use of TARGIT-IORT was safe with no re-recurrence and no detriment to overall survival. This is necessarily a small series, because local recurrence is rare, yet, this novel approach led to a statistically significant improvement in physical wellbeing. These data should increase the confidence in offering breast preservation after in-breast-recurrence of breast cancer.

Abstract OT2-29-01: neoMono - An adaptive randomized neoadjuvant two arm trial in patients with TNBC comparing a mono atezolizumab window followed by atezolizumab and chemotherapy with atezolizumab and chemotherapy

Background: Improvement of systemic treatment of TNBC represents an unmet medical need. Recently, targeted therapy of regulatory immune pathways has become an important option in the treatment of numerous malignancies including breast cancer. Neoadjuvant trials combining chemotherapy and checkpoint inhibitors (KEYNOTE-522 and IMPASSION031) have demonstrated a meaningful benefit regarding pathological complete remission (pCR) and event-free survival (EFS) for the addition of PD-1- and PD-L1-inhibitors to chemotherapy among patients with TNBC, respectively. In addition, initial analyzes have presented promising results regarding event-free survival. In the neoadjuvant GeparNuevo trial only a subgroup of patients with TNBC, receiving a 2-week checkpoint inhibitor monotherapy window before the start of neoadjuvant chemotherapy in combination with checkpoint inhibition, achieved a pCR benefit as compared to patients treated with neoadjuvant chemotherapy alone. Trial Design: NeoMono is a phase 2 randomized multicenter trial recruiting male and female patients with primary TNBC (defined as ER/PR &lt; 10% and HER2 negative). Neoadjuvant treatment in Arm A and B consists of Atezolizumab 1200 mg every 3 weeks in addition to neoadjuvant chemotherapy (i.e. 12 x Carboplatin and Paclitaxel q1w followed by Epirubicin and Cyclophosphamide q3w) In Arm A this therapy is preceded by Atezolizumab 840 mg q2w (Atezolizumab mono window). Study goals are the comparison of efficacy and safety of neoadjuvant chemotherapy with Atezolizumab with and without Atezolizumab two-week window (primary endpoint: pCR) and the identification of biomarkers predicting (early) response to or resistance against Atezolizumab. The broad translational program of the neoMono trial aims at identifying these biomarkers on tumor and patient level. The neoMono statistical design adapts the idea of a proof-of-concept trial and uses Bayesian posterior and predictive probabilities for inference about the primary hypothesis. Up to four planned efficacy interim analyses provide decision points for early stopping for success or futility. The expected maximum number of patients to be recruited is 458.

Citation Format: Cornelia Kolberg-Liedtke, Johannes Schumacher, Ramona Erber, Michael Braun, Bernhard Heinrich, Oliver Hoffmann, Peter Fasching, Helmut Forstbauer, Anke Kleine-Tebbe, Georg Kunz, Michael Lux, Joachim Rom, Christian Schem, Nicole Stahl, Arndt Hartmann, Sabine Kasimir-Bauer, Hans-Christian Kolberg. neoMono - An adaptive randomized neoadjuvant two arm trial in patients with TNBC comparing a mono atezolizumab window followed by atezolizumab and chemotherapy with atezolizumab and chemotherapy [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-29-01.

Update Breast Cancer 2021 Part 4 – Prevention and Early Stages

This past year has seen new and effective options for further improving treatment outcome in many patients with early-stage breast cancer. Patients with hormone receptor-positive disease benefited significantly from the addition of the CDK4/6 inhibitor abemaciclib to endocrine adjuvant therapy. In triple-negative disease, data were presented for two treatment regimens. Patients with advanced disease (stage 2 and 3) benefit from neoadjuvant treatment with the immune checkpoint inhibitor pembrolizumab in combination with standard chemotherapy, regardless of PD-L1 expression. When neoadjuvant therapy has failed to achieve the desired remission in BRCA1 and BRCA2 mutations, the administration of the PARP inhibitor olaparib has demonstrated an impressive response. Other data address translational issues in HER2-positive breast cancer and neoadjuvant therapy approaches with the oral SERD giredestrant and the PARP inhibitor talazoparib. This review presents and analyses the findings of this yearʼ s most important study outcomes.

Update Breast Cancer 2021 Part 5 – Advanced Breast Cancer

Despite the COVID 19 pandemic and mostly virtual congresses, innovation in the treatment of breast cancer patients continues at an unabated pace. This review summarises the current developments. Initial overall survival data for CDK4/6 inhibitor treatment in combination with an aromatase inhibitor as the first advanced line of therapy in treatment-naive postmenopausal patients have been published. Similarly, a trial comparing trastuzumab-deruxtecan versus trastuzumab-emtansine revealed a clear benefit regarding progression-free survival. Understanding of biomarkers making checkpoint inhibitor therapy particularly effective is increasing, and new compounds such as oral selective estrogen receptor destabilisers (SERDs) are entering clinical development and completing the first phase III trials.

Prognostic effect of low-level HER2 expression in patients with clinically negative HER2 status

PURPOSE

Assessment of HER2 overexpression using immunohistochemistry (IHC) and/or in situ hybridisation (ISH) for the detection of HER2 amplifications is standard to identify patients for established HER2-directed treatments. Patients with lower HER2 expression levels have recently also become candidates for novel therapies targeting HER2. This study aimed to assess tumour and patient characteristics and prognosis in patients with advanced breast cancer (aBC), relative to low HER2 expression levels.

METHODS

PRAEGNANT is a prospective aBC registry (NCT02338167), focusing on molecular biomarkers. Patients in all therapy lines receiving any kind of treatment are eligible. This analysis includes patients with conventionally HER2-negative aBC. Clinical outcome was compared in the groups with no (IHC score 0) or with low HER2 expression (IHC 1+, or IHC 2+/ISH negative).

RESULTS

Low HER2 expression levels in triple-negative aBC patients did not influence progression-free survival. Overall survival appeared poorer in patients with IHC 2+ compared with patients with no HER2 expression in the unadjusted analysis (hazard ratio 2.24, 95% confidence interval 0.1.12-4.47). However, this effect was not maintained in the adjusted analysis. In HER2-negative, hormone receptor-positive patients, low HER2 expression appeared to have no effect on prognosis, neither progression-free survival nor overall survival.

CONCLUSIONS

We could not demonstrate that HER2 expression at a low level and assessed in clinical routine can differentiate patients into prognostic groups. However, the prevalence of patients with a low expression makes this population interesting for clinical trials with potentially active treatments using HER2 as a target.

Update Breast Cancer 2021 Part 3 - Current Developments in the Treatment of Early Breast Cancer: Review and Assessment of Specialised Treatment Scenarios by an International Expert Panel

The continuous availability of findings from new studies repeatedly results in updated treatment recommendations and guidelines. In the case of breast carcinoma in particular, several studies have been published in the last few years that have transformed how early and advanced breast carcinoma is being treated. However, this by no means means implies that there is agreement among all experts on specific issues. It is precisely the diversity of interpretation of guidelines and study findings that reflects the constantly changing available data and its complexity, as well as the availability of new drugs. In recent years, new substances such as pertuzumab, T-DM1, neratinib and capecitabine have become available to treat patients with early stages of breast carcinoma. Furthermore, the first results on the use of CDK4/6 inhibitors for adjuvant treatment have now been published. Last but not least, the use of multigene tests to avoid the necessity of chemotherapy in certain patients is still under discussion. This review summarises the state of the data and publishes the results of the survey completed by experts at the 2021 St. Gallen Breast Cancer Conference on early-stage breast cancer.

Is weight-based IV dosing of trastuzumab preferable to SC fixed-dose in some patients? A systematic scoping review

Trastuzumab, a key treatment for HER2-positive breast cancer, is available in weight-based IV and fixed-dose (600 mg) SC formulations. While the Phase 3 HannaH trial indicated non-inferiority of the SC formulation, there is some concern that the target plasma concentration may not be reached in overweight/obese patients whereas low-body-weight patients may be at risk of toxicity. This scoping review evaluated whether overweight/obese patients are at risk of below-target exposure with fixed-dose SC trastuzumab, whether low-body-weight patients are at risk of increased toxicity, especially cardiotoxicity, and whether IV and SC trastuzumab are equivalent in terms of treatment-emergent adverse events (TEAEs) (e.g. infections). Thirty-seven publications that met the eligibility criteria were included. Body weight is not an important determinant of exposure to trastuzumab at steady state (i.e. pre-dose cycle 8); however, real-world evidence suggests that the target concentration (20 μg/mL) may not be reached with the first SC dose in overweight/obese patients. There is no evidence that low-body-weight patients are at increased risk of cardiotoxicity with SC trastuzumab, although this may be confounded by the higher rate of cardiovascular comorbidities in overweight patients. In Phase 3 trials, SC trastuzumab was associated with higher rates of ISRs, ADAs and SAEs, the latter often requiring hospitalization and occurring during adjuvant treatment when patients are not burdened by chemotherapy. The route of administration of trastuzumab (IV vs SC) in different treatment settings should be discussed with the patient, taking into account the risks and benefits associated with each route.

Mutations in BRCA1/2 and Other Panel Genes in Patients With Metastatic Breast Cancer -Association With Patient and Disease Characteristics and Effect on Prognosis

PURPOSE

Among patients with metastatic breast cancer (mBC), the frequency of germline mutations in cancer susceptibility genes and the clinical relevance of these mutations are unclear. In this study, a prospective cohort of patients with mBC was used to determine mutation rates for breast cancer (BC) predisposition genes, to evaluate the clinical characteristics of patients with mutations, and to assess the influence of mutations on patient outcome.

PATIENTS AND METHODS

Germline DNA from 2,595 patients with mBC enrolled in the prospective PRAEGNANT registry was evaluated for mutations in cancer predisposition genes. The frequencies of mutations in known BC predisposition genes were compared with results from a prospective registry of patients with nonmetastatic BC sequenced using the same QIAseq method and with public reference controls. Associations between mutation status and tumor characteristics, progression-free survival, and overall survival were assessed.

RESULTS

Germline mutations in 12 established BC predisposition genes (including BRCA1 and BRCA2) were detected in 271 (10.4%) patients. A mutation in BRCA1 or BRCA2 was seen in 129 patients (5.0%). BRCA1 mutation carriers had a higher proportion of brain metastasis (27.1%) compared with nonmutation carriers (12.8%). Mutations were significantly enriched in PRAEGNANT patients with mBC compared with patients with nonmetastatic BC (10.4% v 6.6%, P < .01). Mutations did not significantly modify progression-free survival or overall survival for patients with mBC.

CONCLUSION

Multigene panel testing may be considered in all patients with mBC because of the high frequency of germline mutations in BRCA1/2 and other BC predisposition genes. Although the prognosis of mutation carriers and nonmutation carriers with mBC was similar, differences observed in tumor characteristics have implications for treatment and for future studies of targeted therapies.

The role of C-reactive protein (CRP) as a prognostic biomarker in patients with early breast cancer (EBC) treated with neoadjuvant chemotherapy (NACT)

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Background: C-reactive protein (CRP) is an acute phase reactant influenced by inflammation and tissue damage. It has been demonstrated that elevated CRP levels are associated with poor outcome of cancer including metastatic breast cancer. However, evidence regarding an impact of CRP levels on outcome in early breast cancer (EBC) are missing. Methods: Patients after neoadjuvant chemotherapy (NACT) for EBC and with available data regarding CRP levels before therapy, pathologic complete remission (pCR) and follow-up were included. The association between CRP at baseline and outcome parameters was analyzed. Results: 156 women were included in this analysis, median follow up was 5.8 years. No association between CRP at baseline and pCR rates could be detected. 6.4% of the patients developed a local recurrence, 10.3% developed a distant recurrence and 5.1% died from breast cancer. A negative correlation (Spearman-Rho) between CRP at baseline and overall survival (OS) (Correlation coefficient (CC) -0.255; p = 0.45), disease free survival (DFS)(CC -0.348; p = 0.075), local recurrence free survival (LRFS)(CC -0.245; p = 0.327) and distant disease free survival (DDFS)(CC -0.422; p = 0.057) was not statistically significant, although especially in DFS and DDFS a strong trend was detected. The probability of death from breast cancer was 2% if the CRP was < 0.08 mg/dl and 40% if the CRP was > 2.08 m/dl, this association was highly statistically significant (Chi Square; p < 0.001). These results were independent from age, estrogen and progesterone receptor status, HER2 status and grading. Conclusions: CRP at baseline is not predictive for pCR in EBC after NACT in our patient dataset. However, an association of parameters of long-term prognosis with CRP could be demonstrated. Although the correlations of higher CRP at baseline and shorter OS, DFS, LRFS and DDFS were not significant, a strong trend could be detected that was reproduced in the analysis of different cut-offs for CRP and the probability of breast cancer mortality. Higher CRP-levels are indicating a worse prognosis in early breast cancer after NACT in this retrospective analysis. These results justify further investigation of CRP as a biomarker of long-term prognosis in early breast cancer in prospective trials.

Association between mammographic breast density and achievement of a pathologic complete remission (pCR) after neoadjuvant chemotherapy (NACT) for early breast cancer (EBC)

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Background: Neoadjuvant chemotherapy (NACT) is indicated in early breast cancer (EBC) with an unfavorable tumor biology. Achievement of pathologic complete remission (pCR) after NACT is indicating an improved prognosis. An association between pCR and mammographic breast density as defined by BIRADS (Breast Imaging Reporting and Data System) could be demonstrated. However, the definition of mammographic breast density by the American College of Radiology (ACR) is widely used worldwide and data regarding an association of breast density by this definition and pCR after NACT are missing. Methods: We conducted a retrospective analysis among patients who had received neoadjuvant chemotherapy (NACT) for EBC and had available data regarding mammographic breast density as defined by ACR before therapy, pCR, age, estrogen and progesterone receptor (ER, PR) status, HER2neu status and grading were included. An association between mammographic breast density (ACR) and pCR was analyzed. Results: 185 patients were included in this analysis, 35.7% of whom achieved a pCR. Mammographic breast density was ACR 1 in 15.1%, ACR 2 in 41.6%, ACR3 in 38.4% and ACR 4 in 4.9% of the patients. A negative correlation (Spearman-Rho) between mammographic breast density and pCR (correlation coefficient (CC) -0.240) was highly statistically significant (p = 0.001). The association of decreasing pCR rates with increasing mammographic breast density (pCR rates by ACR 1: 53.6%, ACR 2: 41.6, ACR 3: 25.4% and 11.1 %) was statistically significant (Chi-Square, p = 0.013). These results were independent of age, ER status, PR status, HER2neu status and grading. Conclusions: In our analysis higher mammographic breast density as defined by ACR was significantly correlated with a lower chance of achieving a pCR after NACT. Although this result has to be interpreted with caution due to the small sample size and the retrospective character of our investigation, it is completely in line with other investigations using other definitions of mammographic breast density. The pathophysiological cause of this association should be further elucidated to reveal potential mechanisms of treatment resistance.

The role of Ki67 in involved lymph nodes as a predictive biomarker for response to neoadjuvant chemotherapy in patients with early breast cancer

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Background: Neoadjuvant chemotherapy (NACT) is a standard in early breast cancer (EBC) with an unfavorable tumor biology and pathologic complete remission (pCR) after NACT is indicating an improved prognosis. Ki67 is well established as a prognostic and predictive biomarker in early breast cancer and the association of high Ki67-results in breast tumors at the time of initial diagnosis and pCR after NACT is used for decision making for versus against NACT in daily routine in many countries. Data about associations of Ki67 in involved lymph nodes and response to NACT are missing. Methods: We conducted a retrospective analysis among patients in our database who had received NACT for EBC, had lymph node involvement verified by core cut biopsy and available data for pCR, age, estrogen and progesterone receptor (ER, PR) status, HER2neu status, Ki67 in the breast tumor and grading. Patients treated in clinical studies were excluded. Ki67 was measured in the archived material of biopsies from involved lymph nodes and the association between Ki67 in involved lymph nodes and response to neoadjuvant chemotherapy was analyzed. Results: 52 patients were included with regard to the criteria mentioned above, 21 had to be excluded because there was not enough lymph node biopsy material for Ki67 analysis. 7 (22.6) of the remaining 31 patients achieved a pCR and 11 (35.5%) achieved a nodal conversion to ypN0. Median Ki67 was 35% [3%, 85%] in involved lymph nodes and 40% [10%, 90%] in the breast. There was no significant correlation (Spearman Rho) between Ki67 in involved lymph nodes and pCR whereas there was for Ki67 in the breast (p = 0.046). The ROC-analysis resulted in a cut-off of 47% with the highest sensitivity for Ki67 in lymph nodes regarding prediction of nodal conversion. An analysis with a cut-off of Ki67 in involved lymph nodes of 47% predicted a nodal conversion in 60% of the cases (Chi-Square and Fisher’s Exact test; p = 0.0049). Conclusions: Our analysis supports Ki67 as a strong predictive biomarker regarding pCR after neoadjuvant chemotherapy. Although high Ki67 expression in involved lymph nodes is significantly associated with nodal conversion, it does not add clinically meaningful information to Ki67 in the breast.

Comparison of therapy benefit from standard anti-HER2 directed approaches in metastatic breast cancer (MBC) between initially HER2-positive patients and patients initially HER2-negative with switch to HER2-positive

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Background: Metaanalyses have demonstrated that 5% of initially HER2 negative breast cancer patients switch to HER2 positive during the course of the disease. Whether there is a difference in benefit from standard HER2 targeted therapies between patients initially HER2 positive and patients switching from negative to positive is unclear. We used data from the PRAEGNANT registry to compare the outcome of those patients. Methods: PRAEGNANT is a prospective advanced breast cancer registry (NCT02338167) focusing on molecular biomarkers. Patients in all therapy lines receiving any kind of treatment are eligible. This analysis compared progression-free survival (PFS) with standard HER2 targeted therapies between patients with tumors initially HER2 negative and switched to HER2 positive and patients with tumors that were initially HER2 positive adjusted for age and hormone receptor status. Results: At the time of this analysis 4061 patients with MBC were included in the PRAEGNANT registry, 49 of which met the requirements for this analysis. Median age was 56 (IQR 48-64) years and 87.8% of the patients were hormone receptor positive. At first diagnosis 15 patients were HER2 negative and 34 patients were HER2 positive. Within a median observation time of 9 months (95%CI: 3.8, 23.7) 35 PFS events occurred. Median observation time was 9 months (95% CI: 3.8, 23.7). Initially HER2 positive patients had a longer progression-free survival (HR = 0.49, 95% CI (0.24, 1.03), p = 0.07) as compared to initially HER2 negative patients switched to HER2 positive. The 1- and 2-year-PFS rates were also higher for patients initially HER2 positive: 1-year-PFS: 52% (95% CI: 36%, 73%) versus 26 % (95% CI: 12%, 52%); 2-year-PFS: 44% (95% CI: 29%, 67%) versus 19% (95% CI: 7%, 50%). Conclusions: Median PFS and 1- and 2-year PFS rate seem to be better in patients HER2 positive at initial diagnosis receiving standard HER2 directed therapies. Although our result has to be interpreted with caution because of the small cohort and the retrospective nature of our analysis, it justifies prospective research including the group of initially HER2 negative patients switched to HER2 positive as a distinct entity. Clinical trial information: NCT02338167 .

Integrative statistical analyses of multiple liquid biopsy analytes in metastatic breast cancer

Background

Single liquid biopsy analytes (LBAs) have been utilized for therapy selection in metastatic breast cancer (MBC). We performed integrative statistical analyses to examine the clinical relevance of using multiple LBAs: matched circulating tumor cell (CTC) mRNA, CTC genomic DNA (gDNA), extracellular vesicle (EV) mRNA, and cell-free DNA (cfDNA).

Methods

Blood was drawn from 26 hormone receptor-positive, HER2-negative MBC patients. CTC mRNA and EV mRNA were analyzed using a multi-marker qPCR. Plasma from CTC-depleted blood was utilized for cfDNA isolation. gDNA from CTCs was isolated from mRNA-depleted CTC lysates. CTC gDNA and cfDNA were analyzed by targeted sequencing. Hierarchical clustering was performed within each analyte, and its results were combined into a score termed Evaluation of multiple Liquid biopsy analytes In Metastatic breast cancer patients All from one blood sample (ELIMA.score), which calculates the contribution of each analyte to the overall survival prediction. Singular value decomposition (SVD), mutual information calculation, k-means clustering, and graph-theoretic analysis were conducted to elucidate the dependence between individual analytes.

Results

A combination of two/three/four LBAs increased the prevalence of patients with actionable signals. Aggregating the results of hierarchical clustering of individual LBAs into the ELIMA.score resulted in a highly significant correlation with overall survival, thereby bolstering evidence for the additive value of using multiple LBAs. Computation of mutual information indicated that none of the LBAs is independent of the others, but the ability of a single LBA to describe the others is rather limited—only CTC gDNA could partially describe the other three LBAs. SVD revealed that the strongest singular vectors originate from all four LBAs, but a majority originated from CTC gDNA. After k-means clustering of patients based on parameters of all four LBAs, the graph-theoretic analysis revealed CTC ERBB2 variants only in patients belonging to one particular cluster.

Conclusions

The additional benefits of using all four LBAs were objectively demonstrated in this pilot study, which also indicated a relative dominance of CTC gDNA over the other LBAs. Consequently, a multi-parametric liquid biopsy approach deconvolutes the genomic and transcriptomic complexity and should be considered in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-021-00902-1.

Update Breast Cancer 2021 Part 1 - Prevention and Early Stages

This review summarises not only the latest evidence on prevention, but also the current research on the treatment of early-stage breast cancer patients. Recent years have seen a growing body of evidence on the risk of high- and moderate-penetrance breast cancer susceptibility genes. A large international consortium has now been able to further refine the answer to the question of the significance of the so-called panel genes. Moreover, the data on treatment selection regarding endocrine efficacy and the decision for or against chemotherapy have also been advanced markedly. There is also new data on adjuvant CDK4/6 (cyclin-dependent kinase 4/6) inhibitors, which are standard in first-line treatment in patients with metastatic HER2-negative, hormone receptor-positive (HR+) breast cancer. For other therapies such as immune checkpoint inhibitors, which have successfully improved the rate of pathologic complete response (pCR) in neoadjuvant treatment settings for patients with triple-negative breast cancer (TNBC), there is a growing understanding of the quality of life and side effects. This is especially important in situations where patients could possibly be cured without such a regimen.

Update Breast Cancer 2021 Part 2 - Advanced Stages, Long-Term Consequences and Biomarkers

This review summarises and discusses significant aspects of recently published studies on patient treatment in advanced breast cancer and on biomarkers in breast cancer. In recent years, a large number of drugs for all molecular subtypes have been developed up to phase III trials. With regard to immune checkpoint inhibitors in metastasised breast cancer, the recent discussion has centred on the best candidate for combined chemotherapy. The oral taxanes could become a new type of oral chemotherapies. There is a growing body of data on biomarkers for the use of CDK4/6 inhibitors, which could also signify further development for other molecular subtypes. New substances have been developed for metastatic HER2+ breast cancer that still result in good remission even after massive prior treatment and/or cerebral metastasis. Similarly, knowledge is growing about targeted therapies with antibody-drug conjugates (ADC) against Trop-2, which could bolster our therapeutic armoury in triple-negative breast cancer (TNBC). In addition, the clinical focus is on understanding how to maintain fertility after breast cancer treatment. Here, pooled analyses provide new insights.

Update Breast Cancer 2020 Part 5 - Moving Therapies From Advanced to Early Breast Cancer Patients

In recent years, significant progress has been made in new therapeutic approaches to breast cancer, particularly in patients with HER2-positive and HER2-negative/hormone receptor-positive (HR+) breast cancer. In the case of HER2-positive tumours, these approaches have included, in particular, treatment with pertuzumab, T-DM1, neratinib and, soon, also tucatinib and trastuzumab deruxtecan (neither of which has yet been authorised in Europe). In patients with HER2-/HR+ breast cancer, CDK4/6 inhibitors and the PIK3CA inhibitor alpelisib are of particular importance. Further novel therapies, such as Akt kinase inhibitors and oral SERDs (selective estrogen receptor down regulators), are already being investigated in ongoing clinical trials. These therapeutic agents are not only being introduced into curative, (neo-)adjuvant therapeutic settings for HER2-positive tumours; a first favourable study on abemaciclib as an adjuvant therapy has now also been published. In patients with triple-negative breast cancer, after many years of negative study results with the Trop-2 antibody drug conjugate (ADC) sacituzumab govitecan, a randomised study has been published that may represent a significant therapeutic advance. This review describes the latest developments in breast cancer subsequent to the ESMO Congress 2020.

Challenges and Opportunities for Real-World Evidence in Metastatic Luminal Breast Cancer

Background

The therapeutic armamentarium for patients with metastatic breast cancer is becoming more and more specific. Recommendations from clinical trials are not available for all treatment situations and patient subgroups, and it is therefore important to collect real-world data.

Summary

To develop recommendations for up-to-date treatments and participation in clinical trials for patients with metastatic breast cancer, the Prospective Academic Translational Research PRAEGNANT Network was established to optimize the quality of oncological care in the advanced therapeutic setting. The main aim of PRAEGNANT is to systematically record medical care for patients with metastatic breast cancer in the real-life setting, including the outcome and side effects of different treatment strategies, to monitor quality-of-life changes during therapy, to identify patients eligible for participation in clinical studies, and to allow targeted therapies based on the molecular structures of breast carcinomas.

Key Messages

This article describes the PRAEGNANT network and sheds light on the question of whether the various end points from clinical trials can be transferred to the real-world treatment situation.

Abstract OT-04-02: The AXSANA trial (AXillary Surgery After NeoAdjuvant treatment): An international prospective multicenter cohort study of the EUBREAST study group to evaluate different surgical methods of axillary staging (sentinel lymph node biopsy, targeted axillary dissection, axillary dissection) in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy (NCT04373655)

Background

The optimal surgical staging of the axilla in patients who convert from a clinically positive (cN+) to a clinically negative node status (ycN0) through neoadjuvant chemotherapy is still unclear. Widely diverse techniques such as full Axillary Lymph Node Dissection (ALND), Targeted Axillary Dissection (TAD), Targeted Lymph Node Biopsy (TLNB) and Sentinel Lymph Node Biopsy alone (SLNB) are given preference in different international guidelines. So far, no comparative data on the oncological outcome or the morbidity of the different procedures are available. Further research is needed to safely de-escalate the radicality of axillary surgery in this patient group.

Trial design

The EUBREAST study group initiated an international prospective cohort study including cN+ patients converting to ycN0 status and treated with different axillary staging techniques according to the standard at their treating institution. Participants are patients with cT1-3 tumors with axillary lymph node metastasis confirmed by core biopsy or fine needle aspiration and scheduled for neoadjuvant systemic therapy. The trial is funded by the AGO-B Study Group, the Claudia von Schilling Foundation for Breast Cancer Research and the AWOgyn (Working Group for Reconstructive Surgery in Oncology-Gynecology) and supported by the NOGGO (North-Eastern German Society of Gynaecologic Oncology) and the German Breast Group.

Primary endpoints: 5-year invasive disease-free survival, 3-year axillary recurrence rate and health-related quality of life (HRQoL). HRQoL will be evaluated using four standardized questionnaires (EORTC QLQ-C 30, EORTC QLQ BR 23, Lymph ICF and SOC-13) at baseline and 1, 3 and 5 years after surgery.

Secondary endpoints are the feasibility and performance of different axillary staging techniques (detection rate, number of removed lymph nodes and association with complications, arm morbidity and quality of life, operating time and use of clinical and economic resources); impact of learning curve, and the detailed mapping of surgical and oncological treatment standards in different countries.

Present accrual (July 7th 2020): 5. The first study participant has been recruited in June 2020.

Target accrual: 3000 patients from EUBREAST member states (20)

Citation Format: Maggie Banys-Paluchowski, Elmar Stickeler, Jana de Boniface, Oreste Gentilini, Marc Thill, Steffi Hartmann, Marina Mangold, Christine Solbach, Jens-Uwe Blohmer, Michael Untch, Matilda Appelgren, Hans-Christian Kolberg, Thorsten Kühn, EUBREAST. The AXSANA trial (AXillary Surgery After NeoAdjuvant treatment): An international prospective multicenter cohort study of the EUBREAST study group to evaluate different surgical methods of axillary staging (sentinel lymph node biopsy, targeted axillary dissection, axillary dissection) in clinically node-positive breast cancer patients treated with neoadjuvant chemotherapy (NCT04373655) [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-04-02.

Abstract PS1-21: Molecular fluorescence-guided surgery using Beva800 for the assessment of tumor margins during breast conserving surgery of patients with primary breast cancer (MARGIN-II)

Introduction:The goal of breast conserving surgery (BCS) for early breast cancer (EBC) is to remove the tumor and a surrounding rim of normal tissue, while preserving as much of the normal breast tissue as possible. Incomplete resections are associated with higher rates of surgical re-excision. Repeat surgeries are not only a burden to patients physically but also psychologically and can delay recommended adjuvant therapies. Accurate determination of tumor margins during surgery is therefore critical for successful outcome. Breast cancer tissue produces significantly higher amounts of VEGF-A than healthy tissue. VEGF-A stimulates tumor angiogenesis and is therefore an excellent target for molecular imaging techniques. The fluorescence imaging agent bevacizumab-IRDye800CW (Beva800) is a conjugate of bevacizumab (a humanized antibody targeting human VEGF) and IRDye800CW (a near-infrared fluorescence dye) which binds specifically to VEGF-A. Beva800 provides a potentially highly efficacious approach to imaging specimen and cavity margins during BCS. Herein we present a phase II study that combined Beva800 with the SurgVision Explorer Air camera for intraoperative margin assessment during BCS for EBC.Methods:MARGIN II is a multicenter open-label single arm prospective clinical trial aimed at evaluating Beva800 for assessment of tumor margins in women with EBC scheduled for BCS. The study was a within-patient comparison of positive tumor margin rates using BCS standard of care compared to intraoperative assessment with 4.5 mg Beva800 and fluorescence imaging with the SurgVision Explorer Air camera. Patients undergoing neoadjuvant chemotherapy were excluded. All patients received a single intra-venous bolus injection of 4.5 mg of Beva800 three days before surgery. The fluorescent signal was visualized during surgery using NIR fluorescence imaging (700-1000 nm). This wavelength window typically has very low tissue auto-fluorescence (filtering out background noise) and greater tissue penetration depth due to reduced haemoglobin absorption. Standard of care assessment was defined as visual inspection, palpation and, in cases of pre-operative wire marking, specimen sonography or mammography. Beva800 efficacy was determined as the number of patients in which a pathology-confirmed positive margin was identified by fluorescence guided surgery using Beva800 but not by standard of care BCS. The results per patient were divided into two clusters: results after standard of care BCS and results after fluorescence guided surgery, according to their margin status at pathology. The need for re-operation because of involved margins within 30 days after the first BCS and the safety of 4.5 mg Beva800 was assessed.Results:The recruitment goal of 40 patients in 5 centers has almost been reached and results of the final analysis will be presented at the meeting.Conclusion:Molecular fluorescence-guided surgery using Beva800 has the potential to change the practice of breast conserving surgery by avoiding unnecessary re-operations. This would lead to fewer interventions, a reduced burden on patients through repeat surgery and reduced delay of adjuvant therapies.

Citation Format: Hans-Christian Kolberg, Carmen Röhm, Angrit Stachs, Florian Schütz, Jens-Uwe Blohmer, Sarah Wetzig, Steffi Hartmann, Jörg Heil, Markus Hahn. Molecular fluorescence-guided surgery using Beva800 for the assessment of tumor margins during breast conserving surgery of patients with primary breast cancer (MARGIN-II) [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 PS1-21.

Gene Expression-Based Prediction of Neoadjuvant Chemotherapy Response in Early Breast Cancer: Results of the Prospective Multicenter EXPRESSION Trial

PURPOSE

Expression-based classifiers to predict pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) are not routinely used in the clinic. We aimed to build and validate a classifier for pCR after NACT.

PATIENTS AND METHODS

We performed a prospective multicenter study (EXPRESSION) including 114 patients treated with anthracycline/taxane-based NACT. Pretreatment core needle biopsies from 91 patients were used for gene expression analysis and classifier construction, followed by validation in five external cohorts (n = 619).

RESULTS

A 20-gene classifier established in the EXPRESSION cohort using a Youden index-based cut-off point predicted pCR in the validation cohorts with an accuracy, AUC, negative predictive value (NPV), positive predictive value, sensitivity, and specificity of 0.811, 0.768, 0.829, 0.587, 0.216, and 0.962, respectively. Alternatively, aiming for a high NPV by defining the cut-off point for classification based on the complete responder with the lowest predicted probability of pCR in the EXPRESSION cohort led to an NPV of 0.960 upon external validation. With this extreme-low cut-off point, a recommendation to not treat with anthracycline/taxane-based NACT would be possible for 121 of 619 unselected patients (19.5%) and 112 of 322 patients with luminal breast cancer (34.8%). The analysis of the molecular subtypes showed that the identification of patients who do not achieve a pCR by the 20-gene classifier was particularly relevant in luminal breast cancer.

CONCLUSIONS

The novel 20-gene classifier reliably identifies patients who do not achieve a pCR in about one third of luminal breast cancers in both the EXPRESSION and combined validation cohorts.

Totality of Evidence Supporting the Use of ABP 980, a Trastuzumab Biosimilar: Practical Considerations

ABP 980 (KANJINTI™, Amgen, Thousand Oaks, CA, USA; Amgen Europe B.V., The Netherlands) is a biosimilar to trastuzumab (Herceptin^®), a monoclonal antibody that selectively binds human epidermal growth factor receptor-2 (HER2). Here we provide a brief overview of the totality of evidence (including analytical [structural and functional] characterization, nonclinical evaluation, and human pharmacokinetic [PK], pharmacodynamic, and clinical assessment comparing ABP 980 with trastuzumab reference product [RP]) that supported the approval of ABP 980, along with practical considerations on the reconstitution and use of the lyophilized product to ensure safe and effective administration. ABP 980 has been shown to be highly similar to the RP, with similar mechanism of action, binding, and potency. Key PK parameters, geometric means ratio (GMR [90% CI]) of C_max and AUC_inf, are comparable and within the equivalence margin of 0.80 to 1.25 (ABP 980: 1.04 [0.99–1.08] versus trastuzumab US: 1.06 [1.00–1.12]; ABP 980: 0.99 [0.95–1.03] versus trastuzumab EU: 1.00 [0.95–1.06]). No clinically meaningful differences were found between ABP 980 and RP in a comparative clinical trial in patients with HER2-positive early breast cancer. Pathological complete response—ABP 980: 48% versus RP: 41% (risk difference [RD], 90% CI: 7.3%, 1.2–13.4; relative risk [RR], 90% CI: 1.188, 1.033–1.366). Sensitivity analyses per central pathology review—ABP 980: 48%; RP: 42% (RD: 5.8%, −0.5 to 12.0; RR: 1.142, 0.993–1.312), with RD and RR falling within predefined equivalence margins. Similar to trastuzumab RP, KANJINTI™ is supplied as a sterile, lyophilized cake to be reconstituted with bacteriostatic water for injection (BWFI) for multiple-dose injection or sterile WFI for single use. Stability data support storage of reconstituted solution at 2–8°C (36–46°F), up to 28 days. Reconstituted solution can be diluted in infusion bags containing 0.9% saline and stored for up to 24 h prior to intravenous administration.