OBJECTIVE To analyze clinical switching patterns and reasons between bevacizumab biosimilar and originator drugs. METHODS The data were collected from 1 175 cancer patients treated with bevacizumab at Ruijin Hospital， Shanghai Jiao Tong University School of Medicine from January 1， 2018， to December 31， 2023. The patients were divided into originator group （n＝250） and biosimilar group （n＝925）. The switching rate， switching type and reasons of the two groups were compared. RESULTS There were no statistically significant differences in the switching rate， switching types， and the number of switches between the two groups （P＞0.05）. Single， one-way switches were the switching type in both groups. The proportion of patients in the biosimilar group who switched due to adverse events was significantly higher than originator group， while the proportion of patients who switched due to treatment costs was significantly lower than originator group （P＜0.05）. There were no statistically significant differences in the proportions of patients who switched due to efficacy and drug accessibility between the two groups （P＞0.05）. CONCLUSIONS The switching between bevacizumab biosimilar and the originator drugs mainly involves single， one- way switches. Treatment costs and drug accessibility are the main factors for the switches among users of originator drugs， while drug accessibility and adverse events are the main factors for the switches among users of biosimilar.

Aims To construct an expression vector of human lncRNA H 1 9 ,and to determine the effect of H1 9 overexpression on MCF-7 cell proliferation. Methods Total RNA was extracted from MCF-7 cells,and the full-length of H1 9 lncRNA was amplified by RT-PCR and subcloned into pcDNA3.1 (-)ex-pression vector.The constructed H1 9 expression vector was transfected into HEK-293T and COS-7 cells and the H1 9 lncRNA expression was evaluated by real-time PCR.Following the transfection of H1 9 expression vec-tor into MCF-7 cells for 0,24h and 48h and H1 9 siR-NA interference fragment into MCF-7 cells for 24h, MCF-7 cell proliferation was determined by MTS as-say.Results A hH1 9-pcDNA3.1 (-)expression vector was successfully constructed. At Forty-eight hours after the transfection with H1 9 expression vector in to MCF-7 cells,cell proliferation was significantly increased in the transfected group compared to those without transfection and to those transfected with a neg-ative control vector,while twenty-four hours after the transfection with H1 9 siRNA interference fragment into MCF-7 cells,cell proliferation was significantly de-creased in the transfected group compared to those transfected with a negative control vector.Conclusion Ectopic overexpression of H1 9 lncRNA can promote breast cancer MCF-7 cell proliferation.