The addition of pertuzumab (P) to trastuzumab (H) and docetaxel improves survival in clinical trials of patients with HER2+ MBC, and is a guideline-recommended standard of care for this population. In the real world, however, various factors may influence treatment decisions. Systematic Therapies for HER2-positive Metastatic Breast Cancer Study (SystHERs) is a fully enrolled (June 2012–June 2016), ongoing, US-based, observational study that captures real-world data for patients with HER2+ MBC. Here, we describe the baseline characteristics and treatment patterns of patients who received 1L PH or H without P.
Eligible patients had HER2+ MBC diagnosed within 6 months of enrollment and were ≥18 years of age. Patients were compared descriptively by 1L treatment (PH vs H without P), defined as any therapy received up to first progression.
As of February 10, 2017, among 978 eligible patients, 949 had received 1L treatment (PH, n = 711; H without P, n = 174; no H, n = 64) (Table). 476 (67%) and 88 (51%) of patients in the 1L PH and H without P cohorts, respectively, remain on study. Median follow-up from 1L treatment start was 22 and 25 months, respectively. In patients treated with PH, median duration of treatment with H and P were 15 and 13 months, respectively. In the H without P cohort, median duration of H was 15 months. Among all patients, 68% (648/949) received 1L PH + taxane.Table:
|PH (n = 711)||H without P (n = 174)|
|Median age at MBC diagnosis, years (range)||55 (21–89)||61 (28–90)|
|White, n (%)||565 (79)||137 (79)|
|Eastern Cooperative Oncology Group performance score 0–1, n (%)||613 (86)||146 (84)|
|Private insurance, n (%)||367 (52)||83 (48)|
|Urban or suburban living location, n (%)||556 (78)||138 (79)|
|De novo, n (%)||379 (53)||88 (51)|
|Estrogen receptor positive and/or progesterone receptor positive, n (%)||496 (70)||126 (72)|
|Visceral, n (%)||476 (67)||108 (62)|
|≥3 metastatic sites, n (%)||232 (33)||43 (25)|
|Liver metastasis, n (%)||300 (42)||47 (27)|
|Central nervous system (CNS) metastasis, n (%)||45 (6)a||15 (9)a|
|Prior cardiovascular disease, n (%)||80 (11)||31 (18)|
|Treatment for early breast cancerb, n (%) Any neoadjuvant or adjuvant therapy Any H||n = 332 293 (88) 187 (56)||n = 86 72 (84) 46 (53)|
|1L treatment patterns, n (%) (Treatments are not mutually exclusive)|
|With chemotherapy Taxane Docetaxel Paclitaxel Platinum||673 (95) 648 (91) 479 (67) 195 (27) 69 (10)||117 (67) 87 (50) 34 (20) 51 (29) 40 (23)|
|With hormonal therapy Aromatase inhibitor Tamoxifen||282 (40) 221 (31) 61 (9)||94 (54) 76 (44) 14 (8)|
In patients who did not receive H, 25% (16/64) had CNS metastasis.b
In patients with recurrent disease.
Of patients with HER2+ MBC in the real-world SystHERs study, 68% were treated with PH + taxane. Compared with patients who received PH, those who received H without P were older, less commonly had liver metastasis, and more commonly had prior cardiovascular disease, suggesting that these characteristics may have influenced the treatment choice between PH vs H without P.
Clinical trial identification
Legal entity responsible for the study
P.A. Kaufman: Consulting fees from Genentech. Contracted research paid to institution from Genentech/Roche. S.A. Hurvitz: Research funding from Amgen, Bayer, Boehringer Ingelheim, Genentech, GSK, Pfizer, Roche, Biomarin, Merrimack, PUMA, Dignitana, Medication. Research and travel from Lilly, Novartis, OBI Pharma. J. O\'Shaughnessy: Consulting fees from Genentech. G. Mason: Advisory Board: Avon Foundation for Women Scientific. D.A. Yardley: Fees for services from Novartis and Genentech. Contracted research paid to institution from Genentech and Novartis. A. Brufsky: Consulting fees from Roche. H.S. Rugo: Fees for services from Genomic Health. Ccontracted research paid to institution from Genentech, Pfizer, Novartis, Lilly, OBI Pharma, GTX, Macrogenics, Merck. M. Cobleigh: Royalties and Receipt of IP rights from Genomic Health. Consulting fees from Genentech/Roche and GSK. Contracted research from Genentech/Roche, Merrimack, Macrogenics, NRG foundation. S.M. Swain: Consulting fees from Genentech/Roche, Novartis, and Pieris. Contracted research paid to institution from Genentech/Roche, Pfizer, Merrimack, and Lilly. D. Tripathy: Consulting fees from Puma Biotech, NEKTAR Pharma, Novartis. Contracted research paid to institution from Novartis. L. Chu, V. Antao, B. Yoo: Employment at Genentech. Stock ownership in Roche. M. Jahanzeb: Consulting fees from Roche. Data and Safety Monitoring Board for Puma.