Open-Label Umbrella Study To Evaluate Safety And Efficacy Of Elacestrant In Various Combination In Patients With Metastatic Breast Cancer

Summary

Objectives

This is a multicenter, Phase 1b/2 trial. The Phase 1b aims at selecting the RP2D dose,
defined as a dose that is associated with less than 33% of patients experiencing a DLT of
elacestrant when administered in combination with alpelisib, everolimus, palbociclib,
abemaciclib, and ribociclib, that is, =1 patient experiencing a DLT out of 6 DLT
evaluable patients. For each combination, this phase will have between 1 and 3 cohorts of
6 DLT-evaluable patients each. The total number of DLT-evaluable patients in all the
combinations will vary between 24 and 72.

The Phase 2 part of the trial will evaluate the efficacy and safety of the various
combinations in patients with ER+/HER2- advanced/metastatic breast cancer.

The treatment arms will be:

- Arm A: 50 patients: elacestrant with alpelisib;

- Arm B: 50 patients: elacestrant with everolimus;

- Arm C: 60 patients (30 patients in each combination): elacestrant with either
abemaciclib or ribociclib;

- Arm D: 90 patients (30 patients in each combination): elacestrant with either
palbociclib, abemaciclib, or ribociclib

- Arm E: 60 patients: elacestrant with capivasertib

Phase 1b will have a total of 90 patients, while Phase 2 will have 310 patients for all
treatment arm combinations.