According to the results of a phase Ib/II clinical trial (OP-1250-002, NCT05266105) (Study Details A Phase 1 Study of Oral OP-1250 in Combination With Palbociclib in HR+/HER2- Breast Cancer Patients ClinicalTrials.gov, 2023), the combination of 30–120 mg of OP-1250 with 125 mg of palbociclib was safe and well tolerated. Here, ERBB2 is linked to breast cancer.