Objective:

To assess the safety of aromatase inhibitors (AIs) in combination with CDK4/6 inhibitors using real-world data.

Approach:

• Data Collection: Utilized the FAERS and JADER databases to collect adverse event reports from Q1 2015 to Q3 2023.

Key Findings:

• A total of 28,495 reports related to combination therapy were included in FAERS.
• Disproportionality analysis identified 150 ADEs, with fatigue, neutropenia, and decreased white blood cell count being the most frequent.
• New signals not mentioned in drug labels included skin hypopigmentation, vertigo positional, and plicated tongue.
• Combination therapy showed stronger reporting signals for neutropenia, anemia, and leukopenia.
• In JADER, 1,186 reports identified 25 positive signals, including neutropenia and increased liver enzymes.

Interpretation:

The study identified key signals consistent with previous clinical trials and detected several ADEs not listed in drug labeling, emphasizing the need for further research on causality.

Limitations:

• The study relies on spontaneous reporting systems, which may have underreporting or reporting bias.
• Data is limited to the specified time frame and may not capture all relevant ADEs.

Conclusion:

This study identified key signals consistent with previous clinical trials and detected several ADEs not listed in drug labeling.