Abstract 283P
Background
Real-world data are needed to characterize the current treatment landscape of HER2+ MBC and the potential sequencing of new anti-HER2 drugs recently approved. Here, we present data from the MBC-Registry of the Austrian Study Group of Medical Tumor Therapy (AGMT).
Methods
The AGMT-MBC-Registry is a multicenter nationwide ongoing retrospective and prospective registry for MBC patients in Austria. In this analysis, patients with known HER2 status, available survival data, at least one treatment line and diagnosis of metastatic disease after 01/04/2013 (pertuzumab available) were included.
Results
As of 15/04/2021, 2,024 patients were included in the registry. Out of 1,847 evaluable patients, 320 (17.3%) were HER2+ and 158 (8.6%) fulfilled the inclusion criteria. In patients with metachronous metastasis (53%), 63% had received trastuzumab-based treatment for early breast cancer. Median OS was 50.1 months (95%CI 40.3-66.1). The drop-out rate from 1st- to 5th-line was 19.6%, 18.9%, 18.4% and 32.1%, respectively. This means that 65.2%, 53.2%, and 36.1% received at least 3, 4, and 5 treatment lines for advanced disease, respectively. In 1st-line, 55% were treated with trastuzumab plus pertuzumab and 10% with T-DM1. In 2nd-line 38% had received T-DM1 and 30% trastuzumab-based chemotherapy or endocrine therapy. In 3rd-line 8%, 18% and 43% had received T-DM1, lapatinib-based and trastuzumab-based therapy, respectively. Table: 283P
| Line | Median PFS* (95%CI) | Median TTNT* (95%CI) | ORR | CBR |
| 1st (n=158) | 13.10 (10.60-16.60) | 13.20 (10.50-15.75) | 48% | 70% |
| 2nd (n=90) | 7.70 (3.40-10.15) | 7.90 (4.70-9.80) | 32% | 63% |
| 3rd (n=49) | 5.20 (3.00-7.00) | 6.85 (3.65-9.25) | 21% | 44% |
| 4th (n=28) | 3.20 (0.15-3.60) | 4.10 (0.70-4.90) | 17% | 30% |
| 5th (n=15) | 3.00 (0.70-3.40) | 4.45 (3.30-5.40) | 0% | 17% |
| ≥6th (n=14) | 2.70 (2.00-3.90) | 3.80 (1.25-4.95) | 7% | 21% |
* calculated in patients with available dataPFS=progression-free survival; TTNT=time to next treatment; ORR=overall response rate; CBR=clinical benefit rate
Conclusions
More than a half of patients with HER2+ MBC in Austria receive at least 4 treatment lines. Treatment benefit diminishes from line to line, underlining the medical need for more effective new compounds as well as studies looking at optimal sequencing of multiple treatment lines.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Austrian Study Group of Medical Tumor Therapy (AGMT).
Funding
Roche, Daiichi Sankyo, Pfizer, AstraZeneca.
Disclosure
S.P. Gampenrieder: Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Research Grant: Roche; Financial Interests, Personal, Other, Travel grant: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Other, Travel grant: Daiichi Sankyo; Financial Interests, Personal, Advisory Board: Seagen. G. Rinnerthaler: Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Other, Travel grant: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo. A.L. Petzer: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Board: Seagen; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Other, Travel grant: Roche. M. Balic: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Other, Travel grant: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Advisory Board: Seagen. S. Heibl: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Other, Travel grant: Roche. A. Zabernigg: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Other, Travel grant: Roche. D. Egle: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Other, Travel grant: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Advisory Board: Seagen. M. Sandholzer: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Other, Travel grant: Roche. F. Roitner: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Other, Travel grant: Roche. M. Hubalek: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Other, Travel grant: Roche. M. Knauer: Financial Interests, Personal, Other, Travel grant: Roche. C.F. Singer: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Advisory Board: Seagen; Financial Interests, Personal, Other, Travel grant: Roche. R. Greil: Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Personal, Other, Travel grant: Roche; Financial Interests, Personal, Other, Travel grant: Daiichi Sankyo. All other authors have declared no conflicts of interest.