Effects of plateau hypoxia on population pharmacokinetics and pharmacodynamics of metformin in patients with Type 2 diabetes / 中南大学学报(医学版)

OBJECTIVES@#Metformin is the basic drug for treating diabetes, and the plateau hypoxic environment is an important factor affecting the pharmacokinetics of metformin, but there have been no reports of metformin pharmacokinetic parameters in patients with diabetes mellitus type 2 (T2DM) in the high-altitude hypoxic environment. This study aims to investigate the effect of the hypoxic environment on the pharmacokinetics and assess the efficacy and safety of metformin administration in patients with Type 2 diabetes mellitus (T2DM).@*METHODS@#A total of 85 patients with T2DM taking metformin tablets in the plateau group (n=32, altitude: 1 500 m) and control group (n=53, altitude: 3 800 m) were enrolled according to the inclusion and exclusion criteria, and 172 blood samples were collected in the plateau group and the control Group. A ultra-performance liquid chromatography/tandem mass spectrometry (UFLC-MS/MS) method was established to determine the blood concentration of metformin, and Phoenix NLME software was used to establish a model of pharmacokinetics of metformin in the Chinese T2DM population. The efficacy and serious adverse effects of metformin were compared between the 2 groups.@*RESULTS@#The population pharmacokinetic modeling results showed that plateau hypoxia and age were the main covariates for model building, and the pharmacokinetic parameters were significantly different between the plateau and control groups (all P<0.05), including distribution volume (V), clearance (CL), elimination rate constant (Ke), half-life(T1/2), area under the curve (AUC), time to reach maximum concentration (Tmax). Compared with the control group, AUC was increased by 23.5%, Tmax and T1/2 were prolonged by 35.8% and 11.7%, respectively, and CL was decreased by 31.9% in the plateau group. The pharmacodynamic results showed that the hypoglycaemic effect of T2DM patients in the plateau group was similar to that in the control group, the concentration of lactic acid was higher in the plateau group than that in the control group, and the risk of lactic acidosis was increased after taking metformin in the plateau population.@*CONCLUSIONS@#Metformin metabolism is slowed down in T2DM patients in the hypoxic environment of the plateau; the glucose-lowering effect of the plateau is similar, and the attainment rate is low, the possibility of having serious adverse effects of lactic acidosis is higher in T2DM patients on the plateau than on the control one. It is probably suggested that patients with T2DM on the plateau can achieve glucose lowering effect by extending the interval between medication doses and enhancing medication education to improve patient compliance.

Economic evaluation of first-line nivolumab plus cabozantinib for advanced renal cell carcinoma in China.

Background: In the Checkmate9ER trial, first-line treatment with nivolumab combined with cabozantinib (NI + CA) has shown efficacy for advanced renal cell carcinoma. This study aims to evaluate the impact of the health and economic outcomes of NI + CA in China. Methods: Clinical efficacy data were derived from pivotal phase III CheckMate 9ER trial. A three-state partitioned survival model was established based on disease progression. Progression-free survival and overall survival of NI + CA vs. sunitinib were fitted with log-logistic and log-normal distributions, respectively. Mixture cure, non-mixture cure, and Royston/Parmar spline models were used to evaluate model robustness. The results derived the computational cost from the Chinese healthcare system perspective. The primary outcomes were quality-adjusted life-years (QALYs), total cost in US dollars, as well as incremental cost-effectiveness ratios (ICERs) at the willingness-to-pay threshold in China. One-way and probabilistic sensitivity analysis were also used to assess the robustness of the model. Results: In the base-case analysis result, 0.86 additional QALYs could be obtained in the NI+CA (3.84 QALYs) versus the sunitinib strategy (2.97 QALYs). The ICER of NI+CA compared with the sunitinib strategy was US$292,945 per QALY. The ICER value in the NI+CA strategy was higher than the Chinese willingness-to-pay threshold of US$38,024 per QALY. Although NI+CA can improve long-term patient survival significantly over sunitinib in the treatment of advanced renal cell carcinoma, it is unlikely to be cost-effective due to high cost. The results of the one-way sensitivity analysis showed that drug cost, health utility value at the stage of disease progression, and subsequent treatment proportion had a greater impact on the stability of ICER values. Conclusions: Nivolumab combined with cabozantinib can prolong the life of patients with advanced renal cell carcinoma and improve their quality of life, but there is a corresponding increase in medical cost. The NI + CA strategy is unlikely to be considered cost-effective in the treatment of advanced RCC from the perspective of Chinese healthcare system.

Research progress of pharmacokinetic factors of metformin / 中国药房

Metformin is the most common first-line oral hypoglycemic drug ，but there are large individual differences in pharmacokinetic parameters and pharmacodynamics during clinical use. The dosage of some patients should be adjusted to achieve satisfactory therapeutic effect. Pharmacokinetic parameters of metformin are affected by many factors ，including respects of transporter gene polymorphism ，drug interaction ，intestinal flora ，plateau hypoxia and physiological function and so on. In order to guide the clinical individualized use of metformin ，this study reviews the research progress on the influencing factors of metformin pharmacokinetics.