Efficacy of Lapatinib in Patients with HER2-Negative Metastatic Breast Cancer and HER2-Positive Circulating Tumor Cells-The DETECT III Clinical Trial

BACKGROUND

The phenotypes of tumor cells change during disease progression, but invasive rebiopsies of metastatic lesions are not always feasible. Here we aimed to determine whether initially HER2-negative metastatic breast cancer (MBC) patients with HER2-positive circulating tumor cells (CTCs) benefit from a HER2-targeted therapy.

METHODS

The open-label, interventional randomized phase III clinical trial (EudraCT Number 2010-024238-46, CliniclTrials.gov Identifier: NCT01619111) recruited from March 2012 until September 2019 with a follow-up duration of 19.5 months. It was a multicenter clinical trial with 94 participating German study centers. A total of 2137 patients with HER2-negative MBC were screened for HER2-positive CTCs with a final modified intention-to-treat population of 101 patients. Eligible patients were randomized to standard therapy with or without lapatinib. Primary study endpoints included CTC clearance (no CTCs at the end of treatment) and secondary endpoints were progression-free survival, overall survival (OS), and safety.

RESULTS

In both treatment arms CTC clearance at first follow-up visit-although not being significantly different for both arms at any time point-was significantly associated with improved OS (42.4 vs 14.1 months; P = 0.002). Patients treated additionally with lapatinib had a significantly improved OS over patients receiving standard treatment (20.5 vs 9.1 months, P = 0.009).

CONCLUSIONS

DETECT III is the first clinical study indicating that phenotyping of CTCs might have clinical utility for stratification of MBC cancer patients to HER2-targeting therapies. The OS benefit could be related to lapatinib, but further studies are required to prove this clinical observation. ClinicalTrials.gov Registration Number: NCT01619111.

Abstract PD3-12: Efficacy of the tyrosine kinase inhibitor lapatinib in the treatment of patients with HER2-negative metastatic breast cancer and HER2-positive circulating tumor cells - results from the randomized phase III DETECT III trial

Background: It is well-known that tumor biology may change during the course of the disease due to clonal evolution, and such changes might have important implications for response to targeted treatments. Circulating tumor cells (CTCs) could serve as a real-time liquid biopsy to detect changes in tumor biology. It has been demonstrated that patients with HER2-negative metastatic breast cancer (MBC) may have discordant, HER2-positive CTCs in the peripheral blood. However, up to now there is no randomized clinical trial investigating whether treatment decisions based on CTC phenotype provide benefits in terms of improved outcome. The aim of the DETECT III study is to investigate whether patients with initially HER2-negative MBC and HER2-positive CTCs benefit from HER2-targeted therapy with the tyrosine kinase inhibitor lapatinib. In addition, the significance of CTCs as an early predictive marker for response to therapy will be analyzed. Methods: The randomized phase III DETECT III trial (NCT01619111) compares lapatinib in combination with standard therapy versus standard therapy alone in patients with initially HER2-negative MBC and HER2-positive CTCs. Efficacy of lapatinib treatment is evaluated by CTC clearance rate, progression-free survival (PFS) and overall survival (OS). In addition, we investigate the association between CTC results and both PFS and OS to assess the utility of CTCs as an early predictive marker for treatment response. CTC enumeration and phenotyping was performed using the CellSearch® technology (Menarini Silicon Biosystems; Bologna, Italy). Survival data are analyzed using log rank tests, univariable and adjusted multivariable cox regressions. Results: First results on CTC clearance rates, PFS and OS of 105 prospectively randomized patients will be presented. Conclusion: This first randomized clinical trial in breast cancer patients with treatment decisions being based on the phenotype of CTCs will show whether patients with HER2 negative MBC and HER2 positive CTCs benefit from additional HER2-targeted therapy with lapatinib. This finding might be increasingly important as novel HER2-targeted drugs become available.

Citation Format: Tanja Fehm, Volkmar Mueller, Maggie Banys-Paluchowski, Peter A Fasching, Thomas WP Friedl, Andreas Hartkopf, Jens Huober, Christian Loehberg, Brigitte Rack, Sabine Riethdorf, Andreas Schneeweiss, Diethelm Wallwiener, Franziska Meier-Stiegen, Oliver Hoffmann, Lothar Müller, Pauline Wimberger, Eugen Ruckhaeberle, Jens Blohmer, Wolfgang Janni. Efficacy of the tyrosine kinase inhibitor lapatinib in the treatment of patients with HER2-negative metastatic breast cancer and HER2-positive circulating tumor cells - results from the randomized phase III DETECT III trial [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 PD3-12.

Relevance of health economics in breast cancer treatment - the view of certified breast centres and their patients

Breast cancer centres - certified in accordance with the criteria of the German Cancer Association and the German Mastology Association - are established throughout Germany. Although the setting up of centres and the subsequent need for certification are associated with a marked increase in costs, initial data show positive effects on quality. Certified centres are cost-effective from the point of view of health economics - they lead to improved quality in processes and results without creating any increase in costs for the funding bodies. However, the organization of the necessary structures, with interdisciplinary treatment, documentation and quality-assurance measures, requires considerable resources. Increasing consolidation of inpatient services is also involved, while shortening of the patients' hospitalization periods is leading to reduced remuneration from the funding bodies. The current cost deficits, which have resulted from the increased resources required, need to be recouped through additional charges. It will only be possible to maintain the high quality achieved if additional charges become available to cover the centres' added costs. Good data are increasingly becoming available as a basis for negotiations on charges - e.g., with regard to the quality of results and the National Cancer Plan - as well as clear support from patients.

Lymphedema in breast cancer survivors: assessment and information provision in a specialized breast unit

OBJECTIVE

Assessment and adequate treatment of lymphedema is required by the European Society of Mastology. The purpose of our study was the evaluation of self-reported incidences of lymphedema in breast cancer survivors and the effect of providing the patients with information about lymphedema on the extent to which lymph-drainage massage services and compression garments were used.

METHODS

A total of 742 breast cancer survivors were analysed in this questionnaire-based survey. The associations between lymphedema and the patients' medical history; morbidity located in the breast, axilla, and arm; the amount of information the patients had received concerning lymphedema; and the extent to which lymph-drainage massage services and compression garments were analyzed.

RESULTS

31.67% of the patients stated to have lymphedema. Radiotherapy was identified as a significant risk factor. Pain, paresthesia, and functional limitations were associated with the occurrence of lymphedema. The only independent positive predictive factor found to be associated with the use of lymph-drainage massage services (OR 5.74) was the provision of information about the condition.

CONCLUSIONS

Self-reported assessment of lymphedema is feasible. The observed lymphedema incidence of approximately 30% may be able to serve as a basis for benchmarking in quality-assurance procedures at breast centers.

PRACTICE IMPLICATIONS

Control mechanisms are required to assess if the indication for lymphdrainage is adequate and the compliance to this subject is sufficient.