Xuanyuening Bireociclib Tablets

1. Indications and Usage
Hormone Receptor-Positive, HER2-Negative Metastatic or Advanced Breast Cancer: Bireociclib is indicated for adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer.
Combination Therapies: It is approved for use in combination with aromatase inhibitors (AI) as initial endocrine therapy, in combination with fulvestrant following disease progression on endocrine therapy, and as monotherapy after progression on two or more endocrine therapies and chemotherapy in the metastatic setting.
2. Dosage and Administration
Combination Therapy: The recommended dose is 360 mg taken orally twice daily with food for 21 days followed by 7 days off (a 28-day cycle).
Monotherapy: The recommended dose is 480 mg taken orally twice daily with food for 21 days followed by 7 days off (a 28-day cycle).
Administration Requirements: Swallow tablets whole; do not chew, crush, or split. Take at approximately the same time each day.
Missed Doses: If a dose is missed, do not make up the dose. Resume with the next scheduled dose.
3. Mechanism of Action
Bireociclib is a potent, selective inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6). By inhibiting these kinases, it prevents the phosphorylation of the retinoblastoma (Rb) protein, thereby arresting the cell cycle at the G1 phase and inhibiting tumor cell proliferation.
4. Safety and Warnings
Hematologic Toxicity: Neutropenia and leukopenia are common. Complete blood counts (CBC) must be monitored regularly, typically every 2 weeks for the first 2 cycles, and then periodically thereafter.
Hepatotoxicity: Elevations in liver transaminases (ALT/AST) and bilirubin have been observed. Liver function tests (LFTs) should be monitored regularly.
Embryo-Fetal Toxicity: Bireociclib can cause fetal harm. Effective contraception is required for females of reproductive potential during treatment and for at least 1 week after the last dose.
Interstital Lung Disease/Pneumonitis: Monitor for new or worsening respiratory symptoms. If suspected, temporarily withhold or permanently discontinue the drug based on severity.
5. Adverse Reactions and Clinical Research
Adverse Reactions: The most common adverse reactions (incidence ≥10%) include neutropenia, leukopenia, anemia, diarrhea, nausea, fatigue, vomiting, headache, and alopecia.
Clinical Research: Clinical trials have demonstrated that Bireociclib, in combination with endocrine therapies or as monotherapy, significantly improves progression-free survival in patients with HR+/HER2- advanced breast cancer compared to endocrine therapy alone.
6. Drug Interactions
CYP3A4 Inhibitors: Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin) can significantly increase bireociclib exposure. Avoid concomitant use; if unavoidable, reduce the dose.
CYP3A4 Inducers: Strong CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin) can significantly decrease bireociclib exposure. Avoid concomitant use.
QTc-Prolonging Agents: Avoid concomitant use with drugs known to prolong the QTc interval.
7. Pharmaceutical Information
Composition: The active ingredient is bireociclib.
Appearance: Tablets.
Storage: Store at controlled room temperature. Protect from moisture.