Sotorasib, an oral small-molecule inhibitor, reportedly exerts promising activity against Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutant tumors. However, the currently administered dose may fail to represent the optimal dose based on the therapeutic efficacy. Herein, we developed a simple and sensitive method using high-performance liquid chromatography with ultraviolet (HPLC-UV) to measure the sotorasib concentration in human plasma. The sotorasib calibration curve exhibited linearity across the concentration range of 0.10-20.0 μg/mL (r = 0.9999). The coefficients of intra- and inter-day validation ranged between 0.79-9.75% and 3.01-6.13%, respectively. The assay accuracy ranged between -3.14 and 5.18%, with > 98.5% recovery. Subsequently, we applied the developed method to estimate sotorasib concentrations in a patient with KRAS G12C-mutated non-small cell lung cancer. We anticipate that our HPLC-UV method will be valuable for assessing the safety and efficacy of sotorasib in larger patient cohorts.
