A Phase 1, First-in-Human Study of MEN2312, a KAT6 Inhibitor, as Monotherapy and in Combination in Participants With Advanced Breast Cancer

Key Inclusion Criteria: * Participant has advanced (locoregionally recurrent or metastatic) breast cancer not amenable to curative therapy. * Presence of genetic alterations in PIK3CA/AKT1/PTEN in participants' tumor tissue. * Participant must have received at least 1 prior line of endocrine therapy for advanced/metastatic disease or participant who has radiological evidence of breast cancer recurrence or progression during or within 12 months from the end of adjuvant treatment with endocrine therapy, as these participants are considered as first-line relapsed participants. * Progression on p…