Table 3.

Price effect on Part D specialty cancer drug use: Marginal effect for a $100 increase in copayment in initial coverage

	All specialty cancer therapy drugs	Specialty antineoplastics
All study sample (N=297,710)
Specialty cancer drug use
Ordinary least squares (OLS)	−0.035(0.022)*	−0.026(0.016)
IV analysis: 2-stage least squares (2SLS)	−0.068(0.029)**	−0.034(0.017)**
Specialty cancer drug spending among users	N=4,254	N=3,561
OLS	−319.55(279.31)	−146.16(225.64)
2SLS	−262.59(435.53)	−1516.71(341.91)
Patients with leukemia (N=11,371)
Specialty cancer drug use
OLS	−0.244(0.210)	−0.220(0.217)
2SLS	−0.423(0.233)*	−0.403(−0.222)*
Specialty cancer drug spending among users	N= 895	N=852
OLS	−466.21(387.34)	−337.20(363.15)
2SLS	450.31(917.01)	529.64(873.16)

Note: Standard errors (clustered within a plan) are in parentheses;

^*p < 0.10,

^**p < 0.05,

^***p < 0.01