An economic analysis of the landmark Cancer and Leukemia Group B (CALGB)/Southwest Oncology Group (SWOG) 80405 trial, which compared bevacizumab and cetuximab in patients with metastatic colorectal cancer, declares bevacizumab the clear winner, because its total cost is $39,000 less than cetuximab.
“Chemotherapy plus bevacizumab costs less and achieves very similar survival and quality-adjusted survival as chemotherapy plus cetuximab for first-line treatment of KRAS wild-type metastatic colorectal cancer,” according to Deborah Schrag, MD, MPH, Chief of the Division of Population Sciences, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, who presented the analysis at ASCO 2015.
At a median follow-up of 24 months, no significant differences were observed in median overall survival or progression-free survival between the treatment groups, which was 29 months and 10.8 months, respectively, with bevacizumab plus chemotherapy and 29.9 months and 10.4 months, respectively, with cetuximab plus chemotherapy.
“Our study objective was to determine the most cost-effective treatment strategy for first-line metastatic colorectal cancer,” said Dr Schrag. “The cost-effectiveness analysis was prospectively planned for CALGB/SWOG 80405, given the high costs of all the study arms.”
The 2014 cost for 1 cycle (8 weeks) of these treatments in the average patient was $9324 for bevacizumab and $20,856 for cetuximab. This was based on an average selling price of $66.60 per 10 mg for bevacizumab given at 5 mg/kg every 2 weeks, and $53.30 per 10 mg for cetuximab, given at 250 mg/m2 every 2 weeks (400 mg/m2 for the first dose).
Dr Schrag and her colleagues calculated the incremental cost-effectiveness and cost-utility ratios for the 2 treatment strategies. Their analysis took into account the utilization and cost of chemotherapy and the major care episodes related to treatment.
They assumed the use of vial sharing and the efficient use of every milligram of drug, that the end-of-life costs were similar between the arms, that the postprogression treatment intensity was identical between the arms, that all hospital regular bed days and intensive care unit days were “created equal,” that the genomic testing costs were identical, and that the arms were similar in terms of provider visits and chair intensity.
The efficacy of the regimens was similar, as were the quality-adjusted life-years (QALYs), Dr Schrag noted; she pointed out that the 2 drugs differ in toxicities but are generally well-tolerated.
The life-years and QALYs, based on the EQ-5D measurements of health outcomes, were 2.88 and 2.75, respectively, for bevacizumab and 3.03 and 2.90, respectively, for cetuximab. The only difference in a subjective measurement was greater “skin satisfaction” with bevacizumab, as was expected.
“There were no meaningful differences” in subjective outcome measures between the arms, Dr Schrag indicated.
The analysis did, however, reveal large cost differences between the treatment arms, which stemmed from differences in the cost of the biologics.
Dr Schrag indicated that if the average selling price of cetuximab was reduced by 45%, the cost would be neutral.
Dr Bach Comments
Peter B. Bach, MD, MAPP, Director of the Center for Health Policy and Outcomes, Memorial Sloan Kettering Cancer Center, NY, commented on Dr Schrag’s study.
“We are in an era when we have decided on a hierarchy of comparative decision-making in cancer that begins with efficacy, then is followed by toxicity and then cost,” Dr Bach said.
“Dr Schrag’s analysis could have been ‘back-of-the-envelope,’ but she spent a lot of effort to lay this out. And she found no statistically significant difference, whether in life-years or QALYs, with 2 drugs that cost considerably different against dealer’s choice backbone chemotherapy,” he said.
“Benefits to some extent are constrained by biology, as are harms. But prices and costs? We accept these prices, put them into our cost-effectiveness analysis….Why not close this loop? If drugs are equal except for cost, why not just say no to the higher-cost agent?”
In fact, that is just what Dr Schrag does. “There’s a good argument” for bevacizumab first line, “and that is what I use,” she said.