Clinical outcomes after palbociclib with or without endocrine therapy in postmenopausal women with hormone receptor positive and HER2-negative metastatic breast cancer enrolled in the TREnd trial

Lorenzo Rossi,
Chiara Biagioni,
Amelia McCartney,
Ilenia Migliaccio,
Giuseppe Curigliano,
Giuseppina Sanna,
Erica Moretti,
Alessandro M. Minisini,
Saverio Cinieri,
Carlo Tondini,
Grazia Arpino,
Antonio Bernardo,
Angelo Martignetti,
Emanuela Risi,
Marta Pestrin,
Luca Boni,
Matteo Benelli,
Laura Biganzoli,
Angelo Di Leo and
Luca MalorniEmail author

Breast Cancer Research201921:71

https://doi.org/10.1186/s13058-019-1149-5

Published: 29 May 2019

Abstract

Currently, there is limited data regarding the effectiveness of standard subsequent line therapies such as endocrine therapy, chemotherapy, or targeted agents after progression on CDK4/6 inhibitor-based regimens. This paper describes time-to-treatment failure beyond progression on palbociclib or palbociclib+endocrine therapy in patients enrolled in the phase II, multicenter TREnd trial. Our results indicate that there is limited benefit from post-palbociclib treatment, regardless of the type of therapy received. A small population of long responders were identified who demonstrated ongoing benefit from a subsequent line of endocrine therapy after progression to palbociclib-based regimens. A translational research program is ongoing on this population of outliers.