Table 1.

ITS regression results of trastuzumab monthly consumption at the national level

	Originator consumption			Overall trastuzumab consumption
	β (95% CI)	SE	P value	β (95% CI)	SE	P value
Baseline level	7.028 (6.931 to 7.125)	0.048	< 0.001	7.028 (6.931 to 7.125)	0.048	< 0.001
Baseline trend	0.025 (0.017 to 0.032)	0.004	< 0.001	0.025 (0.017 to 0.032)	0.004	< 0.001
Level change after originator price reduction	− 0.131 (− 0.249 to − 0.014)	0.058	0.029	− 0.147 (− 0.264 to − 0.029)	0.059	0.016
Trend change after originator price reduction	− 0.019 (− 0.030 to − 0.008)	0.005	0.001	− 0.016 (− 0.026 to − 0.005)	0.005	0.005
Trend after originator price reduction	0.006 (− 0.003 to 0.014)	0.004	0.176	0.009 (0.001 to 0.017)	0.004	0.031
Level change after clinical introduction of the 1st biosimilar in all PLADs	− 0.030 (− 0.112 to 0.053)	0.041	0.472	0.009 (− 0.074 to 0.092)	0.041	0.829
Trend change after clinical introduction of the 1st biosimilar in all PLADs	− 0.011 (− 0.019 to − 0.002)	0.004	0.019	− 0.011 (− 0.020 to − 0.002)	0.004	0.014
Trend after clinical introduction of the 1st biosimilar in all PLADs	− 0.005 (− 0.009 to − 0.001)	0.002	0.008	− 0.002 (− 0.006 to 0.002)	0.002	0.227

ITS interrupted time series, PLADs provincial-level administrative divisions, Dickey–Fuller test P = 0.001 (originator consumption) and P = 0.006 (overall trastuzumab consumption); Durbin-Watson statistics = 2.17 (originator consumption) and 2.21 (overall trastuzumab consumption); values in bold are significant (P < 0.05)