Abstract 314P
Background
Taxanes are one of the most effective chemotherapies (CT) in breast cancer (BC), but the efficacy of taxane rechallenge in early metastatic relapse has been poorly studied. The purpose of this study was to evaluate the efficacy of taxane rechallenge for early metastatic relapse of HER2-negative (HER2-) BC patients who had previously received taxanes.
Methods
We analyzed the French national ESME MBC database, which includes all pts who initiated MBC care between 2008 and 2017 in 18 French centers. We selected all HER2- MBC pts who received CT as first line treatment (trt) for a metastatic relapse occurring 3-24 months after the last previous neo/adjuvant taxane trt. Progression-free and overall survival (PFS, OS) were estimated using Kaplan-Meier method. We used multivariable Cox models to assess for predictors of PFS/OS.
Results
Of 23,501 women MBC pts in the ESME cohort, 1511 pts had received previous taxanes, had early relapsed HER2- MBC and received CT as first-line trt. 775 of them (51.3%) received a taxane-based regimen (96% paclitaxel; 77% concomitant bevacizumab (Bev)), while 736 (48.7%) received another CT. Pts who received taxanes rechallenge had a later time to relapse (median 14.5 vs 11.2 mo, p<0.01). In hormone-receptor positive (HR+)/HER2-, taxane rechallenge led to similar outcomes to those obtained with other CT for both PFS/OS; while taxane + Bev led to higher PFS. Among Triple-negative MBC (TNBC) pts, those treated with a taxane rechallenge had inferior PFS but similar OS, while the addition of Bev increased both median PFS/OS (multivariable analysis adjusted for prognostic factors was showed in the table). The interaction test between taxane rechallenge and time to relapse was not significant for each subtype and both PFS/OS (p>0.2).
Conclusions
Taxane rechallenge in early metastatic relapse of BC seems to be non-inferior to other chemotherapies in HR+/HER2-, while in TNBC early taxane rechallenge without Bev might be inferior regarding PFS. Table: 314P
| Outcome | CT Regimen | N= | Adjusted Hazard ratio* | P value |
| HR+/HER2- | ||||
| PFS | Other CT | 339 | 1 | 0.1 |
| Taxane | 130 | 0.99 [0.8-1.23] | ||
| Taxane + Bev | 252 | 0.82 [0.69-0.98] | ||
| OS | Other CT | 339 | 1 | 0.6 |
| Taxane | 130 | 1.07 [0.84-1.35] | ||
| Taxane + Bev | 252 | 0.94 [0.78-1.14] | ||
| TNBC | ||||
| PFS | Other CT | 397 | 1 | <0.01 |
| Taxane | 98 | 1.33 [1.06-1.67] | ||
| Taxane + Bev | 295 | 0.78 [0.67-0.92] | ||
| OS | Other CT | 397 | 1 | <0.01 |
| Taxane | 98 | 1.06 [0.83-1.34] | ||
| Taxane + Bev | 295 | 0.79 [0.67-0.94] |
*Adjusted for number of metastatic site, performance status and time to relapse.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Luc Cabel.
Funding
The ESME MBC database receives financial support from an industrial consortium (Roche, Pfizer, AstraZeneca, MSD, Eisai, and Daiichi Sankyo). Data collection, analysis and publication are managed entirely by R&D UNICANCER independently of the industrial consortium.
Disclosure
T. De La Motte Rouge: Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: Clovis Oncology; Financial Interests, Personal, Advisory Board: GSK; Financial Interests, Institutional, Advisory Board: MSD; Financial Interests, Personal, Advisory Board: Mylan; Financial Interests, Personal, Advisory Board: Pfizer; Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Board: Tesaro; Financial Interests, Personal, Other, Local PI: AstraZeneca; Financial Interests, Institutional, Other, Local PI: GSK; Financial Interests, Institutional, Research Grant: MSD; Financial Interests, Institutional, Other, Local PI: MSD; Financial Interests, Institutional, Other, Local PI: Netris Pharma; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: Pfizer; Financial Interests, Institutional, Other, Local PI: Pfizer; Financial Interests, Institutional, Other, Local PI: Roche; Non-Financial Interests, Principal Investigator: ARCAGY; Financial Interests, Advisory Role: French National Cancer Institute; Financial Interests, Advisory Role: UNICANCER. All other authors have declared no conflicts of interest.