Abstract P6-17-37: Therapy landscape of patients with metastatic, HER2 positive breast cancer - Data from the real world breast cancer registry PRAEGNANT (NCT02338167)

Purpose: This analysis describes comprehensive real-world data concerning the use of anti-HER2 therapies in HER2 positive metastatic breast cancer (MBC). Specifically, it describes the therapy patterns of treatments with trastuzumab (TZM), pertuzumab+trastuzumab (PTZ/TZM), lapatinib (LAP) and trastuzumab emtansine (T-DM1). Methods: The PRAEGNANT study is a real-time, real-world registry for patients with MBC. Patients can be registered for PRAEGNANT at any time during the course of their metastatic disease and are followed up until death. All therapy lines are documented. This analysis presents the utilization of anti-HER2 therapies as well as therapy sequences. Results: Of 1936 patients within PRAEGNANT at the time of database closure 451 were HER2 positive (23.3%). Within the analysis set (417 patients after an unilateral breast cancer diagnosis), of which 53% were included in PRAEGNANT in the 1stline setting, 241 were treated with TZM (58%), 237 with PTZ (57%), 85 with LAP (20%) and 125 with T-DM1 (30%) during the course of their therapies. The sequence PTZ/TZMaT-DM1 was given to 51 patients (12%). Worse ECOG, negative hormone receptor status, and visceral or brain metastases were associated with a more frequent use of this therapy sequence. Most patients received T-DM1 after a therapy with pertuzumab. Conclusions: Both novel therapies (PTZ/TZM and T-DM1) are utilized in a high proportion of HER2 positive breast cancer patients. As most patients receive T-DM1 after pertuzumab real world data might help to understand whether this sequence has similar efficacy like in the approval study. Citation Format: Lux MP, Hartkopf AD, Huober J, Volz B, Taran F-A, Overkamp F, Hadji P, Tesch H, Haeberle L, Ettl J, Lueftner DI, Wallwiener M, Muller V, Beckmann MW, Belleville E, Wimberger P, Hielscher C, Geberth M, Lermann J, Abenhardt W, Kurbacher C, Wuerstlein R, Thomssen C, Untch M, Fasching PA, Janni W, Fehm TN, Wallwiener D, Brucker SY, Schneeweiss A, Kolberg H-C. Therapy landscape of patients with metastatic, HER2 positive breast cancer - Data from the real world breast cancer registry PRAEGNANT (NCT02338167) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-37.