C4891026 is a prospective, open-label, multicenter, Phase 1b/2 study to evaluate the safety, antitumor activity, and pharmacokinetic (PK) of vepdegestrant in combination with PF-07220060 in the treatment of participants with Estrogen Receptor Positive/Human Epidermal Growth Factor Receptor 2 Negative (ER+/HER2-) Advanced or Metastatic Breast Cancer.
