A Study to Learn About the Study Medicine Called PF-07220060 in Combination With Fulvestrant in People With HR-positive, HER2-negative Advanced or Metastatic Breast Cancer Who Progressed After a Prior Line of Treatment

Overall Survival (OS)

Time frame: Time from the date of randomization to the date of death due to any cause up to approximately 3 years

OR by investigator per RECIST v1.1

Time frame: Time From randomization date (every 8 weeks during the first 48 weeks and then every 12 weeks) to the date of progression OR death whichever occurs first (up to approximately 2 years)

Duration of Response (DOR) as defined by investigator per RECIST v1.1

Time frame: From the date of the first objective response (every 8 weeks during the first 48 weeks and then every 12 week) up to approximately 2 years.

Number of Participants With Clinical Benefit Response (CBR) by investigator per RECIST v1.1

Time frame: From randomization date (every 8 weeks during the first 48 weeks and then every 12 weeks) up to approximately 2 years

Number or Patients with Adverse Events (AEs) by Type

Time frame: From screening until 28 days after the last dose, to approximately 3 years

Number or Patients with AEs by Incidence

Time frame: From screening until 28 days after the last dose, to approximately 3 years

Number or Patients with AEs by Seriousness

Time frame: From screening until 28 days after the last dose, to approximately 3 years

Number or Patients with AEs by relationship to study interventions

Time frame: From screening until 28 days after the last dose, to approximately 3 years

Number of Participants With Abnormal Electrocardiogram (ECG)

Time frame: From baseline to approximately 2 years

Number of Participants With Laboratory Test Abnormalities

Time frame: From screening until 28 days after the last dose to approximately 2 years

EQ-5D-5L

Time frame: Screening Days 1, 15 of Cycle 1 and 2, Day 1 of Cycles 3-6, then Day 1 of every other subsequent Cycle starting with Cycle 8 (eg, Cycles 8, 10, 12, etc) and EoT. Each Cycle is 28 days.

EORTC QLQ

Time frame: Screening Days 1, 15 of Cycle 1 and 2, Day 1 of Cycles 3-6, then Day 1 of every other subsequent Cycle starting with Cycle 8 (eg, Cycles 8, 10, 12, etc) and EoT. Each Cycle is 28 days.

EORTC QLQ Breast Cancer Module 23 (BR23)

Time frame: Screening Days 1, 15 of Cycle 1 and 2, Day 1 of Cycles 3-6, then Day 1 of every other subsequent Cycle starting with Cycle 8 (eg, Cycles 8, 10, 12, etc) and EoT. Each Cycle is 28 days.

Ctrough of PF-07220060

Time frame: Cycle 1 (Day 15), Cycle 2 (Day 1), and Cycle 3 (Day 1). Each Cycle is 28 days