Real world costs and cost-effectiveness of Rituximab for diffuse large B-cell lymphoma patients: a population-based analysis
1 Pharmacoeconomics Research Unit, Cancer Care Ontario, Toronto, Canada
2 Centre for Excellence in Economic Analysis Research, St Michael’s Hospital, Canada
3 Canadian Centre for Applied Research in Cancer Control, Toronto, Canada
4 Department of Surgery, Surgical Outcomes Research Center, University of Washington, Seattle, WA, USA
5 Toronto Health Economics and Technology Assessment Collaborative, Toronto, Canada
6 Clinical Decision Making and Health Care, Toronto General Hospital, Toronto, Canada
7 Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada
8 Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Canada
9 Department of Oncology, Niagara Health System, St Catharines, Canada
10 Division of Medical Oncology & Hematology, Princess Margaret Hospital, Toronto, Canada
11 Institute for Clinical Evaluative Sciences, Toronto, Canada
12 Department of Medicine, Mount Sinai Hospital, Toronto, Canada
13 Provincial Drug Reimbursement Programs, Cancer Care Ontario, Toronto, Canada
14 McGill University, Montreal, Canada
15 Sunnybrook Health Sciences Centre, Toronto, Canada
16 British Columbia Cancer Agency, Vancouver, Canada
17 University of British Columbia, Vancouver, Canada
BMC Cancer 2014, 14:586 doi:10.1186/1471-2407-14-586Published: 12 August 2014
Current treatment of diffuse-large-B-cell lymphoma (DLBCL) includes rituximab, an expensive drug, combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy. Economic models have predicted rituximab plus CHOP (RCHOP) to be a cost-effective alternative to CHOP alone as first-line treatment of DLBCL, but it remains unclear what its real-world costs and cost-effectiveness are in routine clinical practice.
We performed a population-based retrospective cohort study from 1997 to 2007, using linked administrative databases in Ontario, Canada, to evaluate the costs and cost-effectiveness of RCHOP compared to CHOP alone. A historical control cohort (n = 1,099) with DLBCL who received CHOP before rituximab approval was hard-matched on age and treatment intensity and then propensity-score matched on sex, comorbidity, and histology to 1,099 RCHOP patients. All costs and outcomes were adjusted for censoring using the inverse probability weighting method. The main outcome measure was incremental cost per life-year gained (LYG).
Rituximab was associated with a life expectancy increase of 3.2 months over 5 years at an additional cost of $16,298, corresponding to an incremental cost-effectiveness ratio of $61,984 (95% CI $34,087‒$135,890) per LYG. The probability of being cost-effective was 90% if the willingness-to-pay threshold was $100,000/LYG. The cost-effectiveness ratio was most favourable for patients less than 60 years old ($31,800/LYG) but increased to $80,600/LYG for patients 60–79 years old and $110,100/LYG for patients ≥80 years old. We found that post-market survival benefits of rituximab are similar to or lower than those reported in clinical trials, while the costs, incremental costs and cost-effectiveness ratios are higher than in published economic models and differ by age.
Our results showed that the addition of rituximab to standard CHOP chemotherapy was associated with improvement in survival but at a higher cost, and was potentially cost-effective by standard thresholds for patients <60 years old. However, cost-effectiveness decreased significantly with age, suggesting that rituximab may be not as economically attractive in the very elderly on average. This has important clinical implications regarding age-related use and funding decisions on this drug.