This study aims to evaluate the hematological safety of palbociclib with letrozole in African American women with hormone receptor positive HER2 negative advanced breast cancer. Hematological safety is a composite endpoint of episodes of febrile neutropenia and treatment discontinuation due to neutropenia according to current recommendations for management of neutropenia
The study is designed to assess the rate of completion of planned oncology therapy in the absence of a hematological event defined as episodes of febrile neutropenia and treatment discontinuation due to neutropenia. A completion rate of 80% is considered of clinical relevance as to benefit breast cancer patients who are at a higher risk of having ethnic neutropenia where as a completion rate of 60% is considered poor and to justify additional safety studies. A two stage design with a total of 35 patients is used to test if the completion rate is at least 80% versus if it is below 60% with 80% power at a significance level of 5%.
An exact confidence interval of the completion rate will be calculated. Investigators estimate there will be no more than a 10% rate of febrile neutropenia. Due to the small sample size, the analysis of secondary endpoints will be descriptive and will not include specific hypothesis testing.
1. Self-identified Black, African or African American women of ≥ 18 years of age with proven diagnosis of advanced adenocarcinoma of the breast (locoregionally recurrent or metastatic disease)
2. ER-positive and/or PgR-positive tumor based on local laboratory results
3. HER2-negative breast cancer based on local laboratory results (test to be used as per local practice)
4. Patients must be appropriate candidates for letrozole therapy
5. Eastern Cooperative Oncology Group (ECOG) performance status 0-2
6. Adequate bone marrow function:
- Absolute Neutrophil Count (ANC) ≥ 1,000/mm3 (1.0 x 109/L);
- Platelets ≥100,000/mm3 (100 x 109/L);
- Hemoglobin ≥9 g/dL (90 g/L).
1. Current use of food or drugs known to be potent inhibitors or inducers of CYP3A4
2. Active uncontrolled or symptomatic brain metastases. Previously treated and clinically stable, as per Investigator's judgment, brain metastases are permitted.
3. Previous CDK4/6 inhibitor
|Maximum Eligible Age:||N/A|
|Minimum Eligible Age:||18 Years|