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, 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~The total number of patients in Phase 2 for all treatment arm combinations will be 250 patients
This is a multicenter, Phase 1b/2 trial. The phase 1b part of the trial aims to determine the RP2D of elacestrant when administered in combination with alpelisib, everolimus, palbociclib, and ribociclib. 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.