1695 - Impact of pertuzumab and T-DM1 on prognosis of HER2-positive metastatic breast cancer (MBC) and factors affecting their efficacy: results from the AGMT_MBC-Registry

Background

Both pertuzumab and T-DM1 improved overall survival (OS) of HER2+ metastatic breast cancer (MBC) in clinical trials. Little is known about their activity outside of clinical trials and when administered sequentially or after (neo)adjuvant pretreatment. Here we present real-word 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. Unadjusted, univariate survival probabilities of PFS and OS were calculated by the Kaplan-Meier method and compared by the log-rank test, multivariate hazard ratios (HR) were estimated by Cox regression models. In this analysis patients with known HER2 status and available survival data who received at least one palliative treatment line were included.

Results

As of 31/01/2019, 1262 patients were included in the AGMT-MBC-Registry. Out of 1090 evaluable patients, 256 (23.5%) were HER2+. Compared to patients with HER2- disease, HER2 positivity was significantly associated with longer OS (median OS 42.7 vs. 33.6 months; HR 0.80; 95%CI 0.67-0.96; P = 0.017). Patients treated with pertuzumab (106/256=41.4%) or T-DM1 (49/256=19.1%) had a significantly longer OS than patients who were not treated with these agents, respectively (HR 0.35; 95%CI 0.24-0.52; P < 0.001 and HR 0.48; 95%CI 0.31-0.75; P = 0.001). Furthermore, pertuzumab treatment was significantly associated with longer OS in multivariate analysis (P < 0.001). Median PFS of pertuzumab containing treatments was significantly longer when administered in first-line compared to later lines (23.7 vs. 6.3 months; HR 0.35; 95%CI 0.21-0.58; P < 0.001). In T-DM1 treated patients, median PFS of T-DM1 was longer when given in first- or second-line compared to later lines (11.0 vs. 8.4 months) and in pertuzumab naïve patients (11.0 vs. 7.6 months). However, these differences were not statistically significant.

Conclusions

Prognosis of HER2+ MBC has significantly improved by the implementation of pertuzumab and T-DM1 in this real-world population.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Richard Greil.

Funding

Roche, Pfizer.

Disclosure

S.P.P. Gampenrieder: Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution), Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Novartis; Speaker Bureau / Expert testimony: BMS; Advisory / Consultancy, Speaker Bureau / Expert testimony: AstraZeneca; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy: Eli Lilly; Travel / Accommodation / Expenses: Amgen; Travel / Accommodation / Expenses: Shire; Travel / Accommodation / Expenses: Bayer; Travel / Accommodation / Expenses: Celgene; Travel / Accommodation / Expenses: Daiichy Sankyo. G. Rinnerthaler: Advisory / Consultancy: Pierre Fabre; Advisory / Consultancy: Celgene; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self), Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Novartis; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony: Lilly; Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Amgen; Speaker Bureau / Expert testimony: AstraZeneca; Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: BMS. A. Petzer: Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Novartis; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Lilly; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Roche. D. Fuchs: Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Novartis; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: AstraZeneca; Travel / Accommodation / Expenses: Tesa. M. Balic: Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): Amgen; Advisory / Consultancy, Speaker Bureau / Expert testimony: AstraZeneca; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self), Travel / Accommodation / Expenses: Lilly; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: MSD; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Novartis; Advisory / Consultancy, Speaker Bureau / Expert testimony: Pierre Fabre; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self), Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy: Samsung; Speaker Bureau / Expert testimony, Research grant / Funding (self): Celgene; Travel / Accommodation / Expenses: BMS; Travel / Accommodation / Expenses: Boehringer Ingelheim. D. Egle: Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Novartis; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Lilly; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: AstraZeneca. A.F. Zabernigg: Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Honoraria (self), Advisory / Consultancy: Lilly; Honoraria (self), Honoraria (institution), Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer. C.F. Singer: Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Novartis; Honoraria (self), Research grant / Funding (self), Travel / Accommodation / Expenses: Roche; Honoraria (self), Research grant / Funding (self), Travel / Accommodation / Expenses: Amgen; Honoraria (self), Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Pfizer. M. Hubalek: Honoraria (self): Pfizer; Honoraria (institution): AstraZeneca; Advisory / Consultancy: Novartis; Speaker Bureau / Expert testimony: Lilly; Research grant / Funding (self): Amgen; Travel / Accommodation / Expenses: Roche. R. Greil: Honoraria (self), Advisory / Consultancy: Daiichy Sankyo; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self), Travel / Accommodation / Expenses: Roche; Honoraria (self), Research grant / Funding (self): Tarkeda; Honoraria (self), Research grant / Funding (self): Celgene; Honoraria (institution), Research grant / Funding (self): Novartis; Honoraria (self): BMS; Honoraria (self): Amgen. All other authors have declared no conflicts of interest.