Effective therapeutic drug monitoring (TDM) is crucial for optimizing chemotherapy efficacy and minimizing toxicity, especially with potent anticancer drugs like doxorubicin and cyclophosphamide. Traditional TDM practices often rely on centralized laboratory testing, which can suffer from lengthy turnaround times that delay clinical decision-making. To address these limitations, this study aims to develop and validate a novel electrochemical sensor capable of rapid, onsite TDM at the point of care. We have designed a cutting-edge electrochemical sensor utilizing an MXene-modified glassy carbon electrode (GCE) as the working electrode. The choice of MXene was intended to enhance the electrode's sensitivity and selectivity for the targeted detection of doxorubicin and cyclophosphamide. The preliminary results demonstrate that the sensor can detect these drugs within clinically relevant concentration ranges, with a detection limit ranging from 1.10^-4 to 10.10^-4 M. Furthermore, the sensor's performance has been successfully validated by testing blood samples from patients undergoing chemotherapy, confirming that the measurements are both accurate and reliable. The development of this electrochemical sensor marks a significant advancement in the field of TDM, reducing dependence on centralized laboratories and streamlining the monitoring process. This innovative tool not only holds the potential for improving patient outcomes by ensuring optimal drug dosages but also offers possibilities for expanding its applications to monitor other anticancer drugs and immune biomarkers in the future.