Background
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been widely used in the treatment of EGFR mutation non-small-cell lung cancer. The Chinese government has made great efforts to improve the availability and affordability of these drugs. The aim of this study was to investigate the trends in the consumption and cost of EGFR TKIs in Nanjing, a developed city in China, and evaluate the influence of health insurance coverage and national price negotiation on drug consumption.
Methods
Data about EGFR TKIs applications in 2010–2019 were extracted from Jiangsu Medicine Information Institute. Five types of EGFR TKIs were included. Consumption was expressed in defined daily doses (DDDs) and expenditure. The correlation between defined daily cost (DDC) and DDDs was analyzed by Pearson's correlation test.
Results
The DDC, number of DDDs and expenditure of EGFR TKIs changed little from 2010 to 2015. National price negotiation was initiated as a policy and low-price generic gefitinib came into the market in 2016. Three types of EGFR TKIs moved into the coverage of the national health insurance since 2017. Hence, the DDC decreased, and the number of DDDs increased significantly year by year since 2016. The first generation TKIs always made up of comprised the majority of the total consumption. The predominantly prescribed TKIs were gefitinib and icotinib. DDC was negatively correlated with the number of DDDs. The number of DDDs increased significantly after health insurance enrollment, price negotiation and generic drug replacement.
Conclusion
The consumption of EGFT TKIs has increased and the DDC of EGFR TKIs has decreased since 2016. These trends may be attributed to drug reimbursement, price negotiation and generic drug replacement. Further efforts are needed to translate the high consumption of EGFR TKIs into clinical benefits.
The voltage source converter (VSC) based high-voltage DC (HVDC) transmission system usually adopts damping and inertia control to quickly and independently adjust the active- and reactive- power, to improve the frequency stability and suppress the electromechanical oscillations of the power grid. This paper first analyzes the effect of the proportional-derivative (PD) controller parameter on the HVDC output power. The study shows that when the proportional-derivative controller parameter is increased to the limit value, HVDC will operate in the rapid power compensation (RPC) mode. Namely, according to the positive or negative polarities of the rotor speed deviation and the grid frequency deviation, the active- and reactive- power limits are used as the reference to rapidly control the output power, thereby minimizing the system’s unbalanced power, the rotor oscillation, and the frequency fluctuation. To this end, this paper proposes a coordinated active-/reactive- power control strategy for the VSC-HVDC system based on the RPC mode to suppress the grid electromechanical and frequency oscillations. The RPC mode enables HVDC to quickly release/absorb power, to compensate for system’s required power shortage or suppress excess power. When the speed deviation, the frequency deviation, and their rates of change meet the requirements, the damping control is used to make HVDC exit the RPC mode and further enhance the ability of the VSC-HVDC system. Simulation results prove the effectiveness of the proposed power optimization control strategy.
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