PALMIRA is an international, multicenter, randomized, open-label, phase II clinical trial with the objective to evaluate the efficacy and safety of continuation of palbociclib in combination with second-line endocrine therapy (fulvestrant or letrozole) in hormone receptor-positive/HER2-negative Advanced Breast Cancer patients who have achieved clinical benefit during first-line palbociclib-based treatment.
The combination of a CDK4/6 inhibitor with letrozole or fulvestrant is the most active first-line treatment for patients with HR[+]/HER2[‐] advanced breast cancer. Although endocrine sensitivity persists beyond progression, preliminary findings suggest more adaptive resistance mechanisms to endocrine therapy than to CDK4/6 inhibitor. At present, there are no data about prolonging CDK4/6 blockade beyond progression on a CDK4/6 inhibitor.
The aim of this study is to determine whether palbociclib rechallenge combined with second-line endocrine therapy upon progression to a prior palbociclib–based therapy will improve progression-free survival over endocrine therapy alone in HR[+]/HER2[‐] advanced breast cancer patients.
A total of 198 patients will be randomized in a 2:1 ratio to palbociclib plus endocrine therapy (Arm A, N=132) or endocrine therapy alone (Arm B, N=66), until progressive disease or unacceptable toxicity.
Patients previously treated with fulvestrant will change to letrozole treatment, and those previously treated with letrozole, anastrozole or exemestane will switch to fulvestrant treatment.
Currently, the PALMIRA trial is open and recruiting in France, Spain, and the United Kingdom. The patient recruitment started in April 2019.
We thank all participating patients and study team involved in PALMIRA trial.
Author: Pilar Bescós