Abstract
Background
Originator infliximab (marketed as Remicade) was the first biological therapy approved in patients with Crohn’s Disease (CD), and has been proven to be effective for the induction and maintenance of remission in patients with moderate-to-severe disease. Due to its recent patent expiry, an infliximab biosimilar (infliximab-dyyb, marketed as Inflectra) has been introduced in Canada. Recent trials have shown that switching from originator infliximab to its biosimilar is not inferior to continued treatment with originator infliximab, however the molecular complexity and sensitivity to changes in manufacturing of biologics makes it difficult to verify the similarity of biosimilars to their respective originator biologic. Nevertheless, the lower price of infliximab biosimilar compared to originator infliximab has the potential to result in large cost savings for patients with CD.
Aims
The aim of our study was to compare the cost-effectiveness of infliximab biosimilar (Inflectra) to originator infliximab (Remicade) for the management of CD.
Methods
A Markov model was developed to simulate the clinical pathway of patients with moderate-to-severe CD after initiating either originator infliximab or infliximab-dyyb. We calculated the cost and effectiveness of both treatments arms over a 5-year time horizon. Loss of response rates were obtained using the CD data from the NOR-SWITCH non-inferiority trial. Transition probabilities between health states and utility values for each health state were obtained from a review of the literature. The cost of health states were accessed with the CIHI patient cost estimator, and the drug costs of Remicade and Inflectra were determined by the Alberta Health and Wellness Drug Benefit List. Deterministic and probabilistic sensitivity analysis was performed on all key variables.
Results
Using a 5-year time horizon, originator infliximab costs $190,632 per patient and yields 3.63 quality-adjusted life years (QALYs). Infliximab-dyyb costs $128,306 per patient and yields 3.15 QALYs. Using a willingness-to-pay (WTP) threshold of $50,000 per QALY, infliximab-dyyb has a 83% probability of being cost-effective, whereas originator infliximab has a 17% probability of being cost-effective. The cost-effectiveness of each treatment at a range of WTP thresholds is shown in Figure 1.
Conclusions
Infliximab biosmilar resulted in large cost savings despite similar effectiveness to originator infliximab for patients with moderate-to-severe CD. Based on the results of our model, the mainstream usage of infliximab biosimilar (Inflectra) may help reduce the economic burden associated with CD.
Cost-effectiveness acceptability curve demonstrating the probability that each treatment option is cost-effective at a range of willingness-to-pay thresholds.
Funding Agencies
The Centre of Excellence for Gastrointestinal Inflammation and Immunity Research