Zebeike Niraparib Tosylate and Abiraterone Acetate Tablets

1. Indications and Usage
Prostate Cancer: Abiraterone acetate is indicated for the treatment of metastatic castration-resistant prostate cancer (mCRPC) and metastatic high-risk castration-sensitive prostate cancer (mCSPC).
Parp Inhibitor Context: Niraparib is primarily indicated for advanced ovarian cancer, fallopian tube cancer, primary peritoneal cancer, and endometrial cancer. Its use in prostate cancer is investigational, typically within clinical trials targeting homologous recombination repair-deficient tumors.
2. Dosage and Administration
Niraparib Dosage: The recommended starting dose is 200 mg orally once daily. Dosing is based on weight and platelet count, with possible reductions to 100 mg. It can be taken with or without food.
Abiraterone Dosage: The recommended dose is 1000 mg orally once daily.
Abiraterone Administration: Must be taken on an empty stomach (at least 1 hour before or 2 hours after a meal). It must be administered concomitantly with prednisone or prednisolone (5 mg once daily).
Combination Note: Since no fixed-dose combination exists, these drugs are managed as separate regimens with individualized dose adjustments based on toxicity.
3. Mechanism of Action
Niraparib: A potent, selective inhibitor of poly (ADP-ribose) polymerases (PARP) 1 and 2. It inhibits PARP-mediated DNA repair, leading to synthetic lethality in tumor cells with homologous recombination deficiencies.
Abiraterone: An irreversible inhibitor of CYP17A1 (cytochrome P450 17A1). This blocks androgen biosynthesis in testes, adrenals, and tumors, profoundly depleting androgens that drive prostate cancer growth.
4. Safety and Warnings
Niraparib Warnings: Risk of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Monitoring of complete blood counts (CBC) is required.
Abiraterone Warnings: Mineralocorticoid excess (hypertension, hypokalemia, fluid retention) and hepatotoxicity. Concomitant corticosteroid use is mandatory to mitigate mineralocorticoid effects.
General: Both agents carry risks of fatigue and cardiovascular events.
5. Adverse Reactions and Clinical Research
Niraparib Common Reactions: Thrombocytopenia, anemia, neutropenia, nausea, and fatigue.
Abiraterone Common Reactions: Hypertension, hypokalemia, edema, arthralgia, and fatigue.
Clinical Research: Abiraterone has demonstrated significant overall survival benefits in mCRPC and mCSPC. Niraparib in prostate cancer is an emerging area of study for patients with specific DNA repair mutations.
6. Drug Interactions
Abiraterone Interactions: Abiraterone is metabolized by CYP3A4. Strong CYP3A4 inhibitors (e.g., ketoconazole) may increase abiraterone exposure, while strong inducers (e.g., rifampin) decrease it.
Niraparib Interactions: Niraparib may be affected by P-glycoprotein (P-gp) inhibitors/inducers.
7. Pharmaceutical Information
Niraparib: Typically supplied as enteric-coated tablets (e.g., 50 mg, 100 mg, 200 mg).
Abiraterone: Typically supplied as tablets (e.g., 250 mg).
Storage: Both are generally stored at controlled room temperature (20-25°C).