Observing the safety and effectiveness of IBRANCE® in breast cancer patients

Post Marketing Surveillance Study to Observe Safety and Efficacy of IBRANCE®

Observational Pfizer · NCT03445637

This study is testing how safe and effective IBRANCE® is for women with advanced breast cancer over nine years to ensure it works well in everyday treatment.

Quick facts

Study typeObservational
Enrollment540 (estimated)
Ages18 Years and up
SexFemale
SponsorPfizer Industry-sponsored
Locations1 site (Seoul)
Trial IDNCT03445637 on ClinicalTrials.gov

What this trial studies

This observational study aims to monitor the safety and efficacy of IBRANCE® in women with advanced or metastatic breast cancer as part of a post-marketing surveillance commitment to the Ministry of Food and Drug Safety in Korea. The study will involve at least 1,000 participants who will receive IBRANCE® in routine clinical practice over a period of nine years following its approval. Participants must meet specific eligibility criteria, including being diagnosed with estrogen receptor-positive and/or progesterone receptor-positive breast cancer. The study will collect data on patient outcomes to ensure ongoing safety and effectiveness of the medication.

Who should consider this trial

Good fit: Ideal candidates for this study are women aged 18 and older with a confirmed diagnosis of advanced or metastatic breast cancer who are suitable for hormone therapy.

Not a fit: Patients who are pregnant or have known hypersensitivity to letrozole or any CDK4/6 inhibitor are unlikely to benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide valuable insights into the long-term safety and efficacy of IBRANCE® for patients with metastatic breast cancer.

How similar studies have performed: Other studies have shown success in monitoring the safety and efficacy of medications in similar patient populations, making this approach well-established.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria

* Women of ≥18 years of age with proven diagnosis of advanced/metastatic breast cancer (locoregionally recurrent or metastatic disease).
* Estrogen Receptor+ (ER+) and/or Progesterone Receptor+ (PgR+) tumor based on local laboratory results (test as per local practice).
* Human Epidermal Growth Factor Receptor 2 -(HER2-) breast cancer based on local laboratory results (test as per local practice or local guidelines)
* Patients must be appropriate candidates for hormone therapy.
* Evidence of a personally signed and dated informed consent document indicating that the patient (or a legally acceptable representative) has been informed of all pertinent aspects of the study.
* During the post marketing surveillance (PMS) period, patients who initially administer IBRANCE®

Exclusion Criteria

* Known hypersensitivity to letrozole or its excipients or to any Cyclin-Dependent Kinase 4/6 (CDK4/6) inhibitor excipients.
* Pregnant women

Where this trial is running

Seoul

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Breast NeoplasmMetastatic breast cancersafetyibrance
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.