[Determination of blood levels for oral anticancer drugs]

Area of Science:

• Oncology
• Pharmacology
• Cancer Therapeutics

Background:

• Oral tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin (mTOR) inhibitors are crucial in treating various cancers, typically given at fixed doses.
• Recent studies reveal significant inter-individual variability in drug exposure to these agents.
• Understanding drug exposure, clinical response (efficacy and toxicity), and drug-food interactions is essential for optimizing cancer therapy.

Purpose of the Study:

• To review the variability in exposure to oral TKIs and mTOR inhibitors.
• To explore the relationship between drug plasma concentrations, clinical response, and drug interactions.
• To provide guidance on individualized dosing strategies for specific targeted therapies.

Main Methods:

• Review of observational studies reporting drug exposure variability.
• Analysis of relationships between plasma concentrations, efficacy, and toxicity.
• Evaluation of known drug and food interactions.
• Synthesis of data to inform dosing recommendations.

Main Results:

• Significant variability in plasma concentrations of oral TKIs and mTOR inhibitors observed across patients.
• Correlation established between drug exposure levels and clinical outcomes (efficacy and toxicity).
• Identified key drug-food interactions impacting drug bioavailability and efficacy.

Conclusions:

• Individualized dosing based on therapeutic drug monitoring is recommended for oral TKIs and mTOR inhibitors.
• Optimized dosing strategies can enhance treatment efficacy and minimize adverse events in cancer patients.
• Specific recommendations provided for pazopanib, sunitinib, and imatinib in metastatic renal cell cancer and gastrointestinal stromal tumors.