Direct cost-survival analysis of therapies for metastatic colorectal cancer

Abstract

3515 Background: Patients with metastatic colorectal cancer (mCRC) treated with 5Fluorouracil plus leucovorin (5FU/LV) have a median life expectancy (LE) of approximately12 months. The addition of irinotecan, oxaliplatin, bevacizumab and cetuximab has increased LE significantly. Although they have been widely adopted, little is known about the financial impact of these new drugs. Methods: Using published reports and aggregate data from NCCTG 9741, we developed a Markov Model which assumes forward progression through up to three lines of therapy compared to 5FU/LV alone. Patients who do not die of toxicity (tox) transition through supportive care prior to death. State changes are based on progression and dose-limiting toxicity. Drug costs are based on Average Sales Price. No other direct or indirect costs are included. Dose modifications for toxicity are defined as 80% of standard doses. Sensitivity analyses (SA) were performed on key variables. Results: LE, total drug costs, and cost-effectiveness (CE) ratios compared to single line-5FU/LV and FOLFOX for 9 commonly used treatement sequences are presented below. SA show that results are sensitive to progression rates,drug costs and length of time on supportive care. Changes in 1st line tox rates have a greater impact on final results than changes in 2nd or 3rd line therapy tox rates. Conclusions: Using drug costs alone, this model shows sequential combination therapy including all available agents to cost $2000-$2800K/week life gained ($100-$145K/year) compared to both 5FU/LV and FOLFOX. For clarity only 9 strategies are presented, but the model presented will contain multiple sequences consisting of 1–3 lines of therapy. Refined tox data, associated costs and quality of life adjustments are needed for realistic comparisons among specific combinations. Combination therapy may have CE ratios similar to other currently accepted intensive medical interventions. These data can help inform discussions of how the cost of care impacts patients, providers, and societies. [Table: see text] [Table: see text]