Overview of Drug-Drug Interactions Between Ritonavir-Boosted Nirmatrelvir (Paxlovid) and Targeted Therapy and Supportive Care for Lung Cancer.

Introduction: Oral administration of ritonavir-boosted nirmatrelvir (Paxlovid) was found to be promising in the treatment of coronavirus disease 2019. The active antiviral component nirmatrelvir in Paxlovid is co-formulated with ritonavir, a strong cytochrome P450 (CYP) 3A4 inhibitor. Many oral targeted therapies indicated for lung cancer are known substrates of CYP 3A4, and concurrent use with Paxlovid may lead to potential drug-drug interaction (DDI). The purpose of this review is to evaluate the potential DDI between targeted therapies and supportive care for lung cancer and ritonavir-boosted nirmatrelvir. Methods: Drug database search in PubMed and the Food and Drug Administration was conducted to identify pharmacokinetic data on oral tyrosine kinase inhibitors (TKIs) used in NSCLC, both Food and Drug Administration approved and those in development. Metabolism pathways for various TKIs are extracted, and the impact of TKI area under the curves and maximum concentration by strong CYP 3A4 inducers and inhibitors is summarized. The most common toxicities and supportive care medications for the TKI were identified. Results: Among EGFR and exon 20 insertion inhibitors, afatinib is least likely to be affected by CYP 3A4, followed by dacomitinib and osimertinib. Among ALK inhibitors, alectinib is the least susceptible to CYP 3A4. ROS1 inhibitors are affected by CYP 3A4 inhibition with the exception of crizotinib. Among MET inhibitors, capmatinib is substantially affected by CYP 3A4 inhibition. Drug exposure of RET inhibitors is expected to increase with CYP 3A4 inhibition, with selpercatinib being the least affected. Certain supportive care medications for lung cancer TKI may have relevant DDIs. Conclusions: The clinical impact of the DDI between lung cancer TKI and ritonavir-boosted nirmatrelvir varies largely on the basis of the susceptibility of CYP 3A4 inhibition caused by the antiviral. Close monitoring and medication adjustments (i.e., dose changes or alternative coronavirus disease 2019 therapy) can be used to overcome DDI to ensure patient safety.