This study aimed to aid decision makers by analyzing the impact of introducing biosimilar prescription targets on physician prescribing behavior in the prescription of biologic erythropoiesis-stimulating agents in Germany.
We combined secondary data of regional level biosimilar prescription targets and secondary data of routinely collected claims data of dispensed prescriptions by physicians operating within the statutory health insurance system in ambulatory care across 7 German regions from 2009 to 2015. Two-way fixed-effects regression analysis was used to identify the average treatment effect of introducing biosimilar prescription targets at the physician level. The main outcome of interest was the share of biosimilar prescriptions on all prescriptions within the substance group. We compared 6 regions that introduced biosimilar prescription targets with 1 region without any prescription target policy.
Introducing biosimilar prescription targets increased the average share of biosimilars between 6 percentage points (P < .05) in Hamburg and up to 20 percentage points (P < .001) in Saxony-Anhalt. Stratification of specialists by prescription volume and adoption status indicated heterogeneous effects. We identified similar but higher effects for high-volume prescribers. Disentangling of effects with regard to the composition of biosimilar share suggested that the increase in biosimilar share was driven by increased biosimilar use accompanied by a nonsignificant decrease in original biologics prescriptions.
Prescription targets to alter physician prescribing behavior meet their intended goals by increasing biosimilar share. Physicians partly responded to the policy by decreasing overall prescriptions of the target substance. Prescription targets might be a useful tool, but decision makers need to consider all aspects of potential responses.