Objective To establish a quality control method for monitoring the blood concentrations of cyclosporin A and tacrolimus by HPLC-MS/MS,and to evaluate the quality control samples using the Westgard multi-rule theory.Methods HPLC-MS/MS was used to determine the concentration of cyclosporin A and tacrolimus in human whole blood.The quality control samples of low,medium and high concentration levels in the therapeutic drug monitoring process were statistically analyzed,Levery-Jennings and Z-score quality control charts were drawn,and the Westgard multi-rule theory was applied for in-house quality control evaluation.Results The established method was fully validated with linear ranges of 10.40-1 040.00 ng·mL-1 and 0.50-49.50 ng·mL-1,the quantification limits were 10.40 and 0.50 ng·mL-1,respectively.The extraction recoveries were 108.61％-113.24％and 101.99％-109.37％,respectively.The matrix factors normalized by internal standard were 106.68％-111.27％and 95.70％-97.81％for cyclosporin A and tacrolimus,respectively.The intra-day and inter-day accuracy and precision were less than 15.0％.Other parameters were also validated and met the acceptance criteria.Levery-Jennings and Z-score quality control charts showed that there were 4 warnings(violation of the 12s rule)in the results of the 26 groups of quality control samples in the third quarter of 2022,and no phenomenon was observed to be out of control.Conclusion The established in-house quality control system for therapeutic drug monitoring of cyclosporin A and tacrolimus can effectively ensure the accuracy of blood drug concentration detection.

OBJECTIVE To evaluate the cost-utility of switching to gemcitabine maintenance therapy for patients with unresectable malignant mesothelioma after first-line chemotherapy from the perspective of China’s healthcare system. METHODS A partitioned survival model was constructed based on data from the NVALT19 trial， with a cycle length of 21 days， a time horizon of 10 years， and a discount rate of 5%. Key model outputs included total costs， quality-adjusted life year （QALY）， incremental costs， and incremental cost-effectiveness ratio （ICER）， etc. Cost-utility analysis was conducted to evaluate the cost- effectiveness of gemcitabine maintenance therapy （gemcitabine group） plan versus best supportive care （supportive care group） plan for the patients with unresectable malignant mesothelioma after first-line chemotherapy. Sensitivity analyses were performed. RESULTS Compared with the supportive care group plan， the gemcitabine group plan had an ICER of 54 860.50 yuan/QALY， which was significantly lower than the willingness-to-pay （WTP） threshold （3 times China’s 2023 per capita gross domestic product， 268 077 yuan/QALY）， indicating that gemcitabine group plan was cost-effective. One-way sensitivity analysis revealed that end-of-life care costs and adverse event management costs in the gemcitabine group had the greatest impact on ICER. Probabilistic sensitivity analysis showed gemcitabine group plan was 100% cost-effective when WTP exceeded 270 000 yuan/QALY. CONCLUSIONS From the perspective of China’s healthcare system， switching to gemcitabine maintenance therapy after first-line chemotherapy is cost-effective for unresectable malignant mesothelioma.

Third space fluid(TSF) is a common complication of advanced malignancies, including malignant pleural effusion, malignant ascites, intracranial effusion, and pelvic effusion, etc. The pharmacokinetics(PK) of anti-tumor drugs in vivo are influenced by various factors, and TSF is one of the potential factors that contributes to PK variations, which may consequently affect the efficacy and safety of anti-tumor drugs. This paper aimed to comprehensively investigate PK studies related to anti-tumor drugs in patients with malignant tumors accompanied by TSF. The paper summarized the PK characteristics of common cytotoxic drugs, small molecule targeted drugs, and monoclonal antibodies in both blood and TSF.