Impact of Drug Substitution on Cost of Care: an Example of Economic Analysis of Cetuximab Versus Panitumumab

Background: The alarming increase in the cost of cancer care is forcing all stakeholders to re-evaluate their approach to treatment. Drugs are the main contributor to the cost. To evaluate the significance of drug substitution on the cost of care we assessed the economic value of panitumumab vs. cetuximab in chemo-refractory metastatic CRC (mCRC) with wild-type KRAS from a US societal perspective.

Methods: We developed a Markov model with three health states: progression-free, progressive, and death. We calculated the transition probabilities between states using the ASPECCT trial report and US life tables. Costs of drug and administration were based on the Medicare reimbursement rates. Published data were used for cost of toxicities and utilities. All costs were converted to 2017 US dollars. The model used quality-adjusted life-years (QALYs) to measure health outcomes for each treatment option.

Results: Panitumumab and cetuximab produced 0.45 QALYs at a per patient cost of $66,006 and $71,956, respectively. The incremental net monetary benefit of panitumumab compared to cetuximab is $5237 under a societal willingness-to-pay threshold of $150,000. The model showed robustness to one-way sensitivity analyses and various alternative scenarios and was found to be most sensitive to the cost of cetuximab.

Conclusions: Panitumumab can lower the cost of care without impacting outcomes in chemo-refractory mCRC settings. This finding provides a strong argument to consider panitumumab in lieu of cetuximab in these patients.