CYP3A4-mediated metabolic variability drives resistance and systemic toxicities under targeted therapies for non–small cell lung cancer

Targeted therapies, including small molecule inhibitors of mutant ALK, EGFR, and RAS in lung cancers, can produce strong and durable clinical responses, yet a subset of tumors fail to respond, and even strong responders eventually relapse. Further, although targeted therapies are typically well tolerated, a subset of patients displays dose-limiting adverse effects. Therapy resistance is generally considered to be a tumor-intrinsic phenomenon, mediated by cell-intrinsic or microenvironmental mechanisms. We found that hyperactivation of CYP3A4, a P450 family enzyme, can lead to tumor-extrinsic resistance by altering pharmacokinetics and reducing systemic and tumor drug exposure, whereas reduced CYP3A4 activity is expected to increase systemic toxicities. Retrospective analysis of clinical cohorts suggests that variability in CYP3A4 activity might be a major contributor to variability in clinical outcomes. To understand the consequences of altered drug metabolism, we developed a mathematical model linking variability in CYP3A4 activity with temporal variability in systemic drug concentrations. These in silico studies indicate that the impact of altered CYP3A4 activity can be mitigated by altering drug dosing and intervals. Further, we demonstrate that tumor sensitivity can be restored by pharmacological inhibition of CYP3A4. These findings establish systemic metabolic variability as a clinically actionable driver of both resistance and toxicity and provide a framework for personalized dosing to improve safety and efficacy of targeted therapy. The Bulk RNA sequencing data is from mouse livers, either untreated or treated with candidate drug JIB-04 to assess the change in gene expression landscape.