This phase 3 clinical trial compares the safety and efficacy of palazestrant (OP-1250) to the standard-of-care options of fulvestrant or an aromatase inhibitor in women and men with breast cancer whose disease has advanced on one endocrine therapy in combination with a CDK4/6 inhibitor.
Adult female or male participants.
ER+, HER2- locally advanced or metastatic breast cancer that is not amenable to curative therapy.
Evaluable disease (measurable disease or bone-only disease).
Previously received a CDK4/6 inhibitor in combination with an endocrine therapy in the advanced setting. One additional line of ET as a monotherapy is allowed. Duration of the most recent prior ET must be at least 6 months.
Symptomatic visceral disease, imminent organ failure, or any other reason that makes the participant ineligible for endocrine monotherapy.
Previously received chemotherapy in the advanced/metastatic setting.
Previously received treatment with elacestrant or an investigational estrogen receptor-directed therapy.
History of allergic reactions to study treatment.