New, Real-World Data for Rituximab Use in NHL Raise Cost-Effectiveness Issues

June 2011, Vol 2, No 3 -

Baltimore, MD—Using real-world administrative data to examine the costeffectiveness of rituximab (Rituxan), a Canadian team found that the 2-year absolute survival benefit is lower than the overall survival uncovered in other studies, and that the 5-year incremental cost is higher, according to the new data presented at the 2011 International Society for Pharmacoeconomics and Outcomes Research’s annual meeting.

“After we’ve gone over the data, and they’ve been published in a peer-reviewed journal, we’ll be sharing the results with decision makers here, saying, ‘This is evidence in the real world of what you’re paying, and what you’re getting in return,’” said co–lead investigator Jeffrey Hoch, PhD, Director, Pharmacoeconomics Research Unit, Cancer Care Ontario, Toronto. “This may inform changes in drug formulary policy,” he noted.

Dr Hoch, with researchers from Cancer Care Ontario and 12 other researchers, received a grant from the Ontario Ministry of Health Drug Innovation Fund. This was the first study in Canada to incorporate recently developed statistical methods for analyzing costs and cost-effectiveness of a cancer treatment.

Analyzing data from the New Drug Funding program in Ontario—which pays for expensive intravenous cancer drugs—identified 2825 patients who received rituximab for diffuse, large Bcell lymphoma, the most common form of non-Hodgkin lymphoma (NHL).

Historically, the most common treatment for NHL was CHOP (Cytoxan [cyclophosphamide], hydroxydaunorubicin, Oncovin [vincristine], prednisone/prednisolone]. However, in 2001 the New Drug Funding program began paying for the addition of rituximab to CHOP (R-CHOP), initially for older patients (aged 60->80 years) and later (in mid-2004) adding younger patients aged <60 years.

The investigators compared data from patients treated with R-CHOP between 2001 and 2007 and patients treated with CHOP between 1997 and 2004.

To control for significant differences in the 2 sets of patients—for example, the patients receiving CHOP were significantly younger and had much less morbidity—they “hard-matched” the 2 cohorts on age for a total of 1131 in each group. This entailed matching each patient treated with CHOP with a patient treated with R-CHOP of exactly the same age. Patients were also paired by the likelihood of receiving rituximab. The 2 cohorts were similar in both characteristics and treatment choice.

The results showed that 3-year overall survival was 10% higher with RCHOP than with CHOP and 8% higher at 5 years. In addition, the 2-year absolute survival benefit with the addition of rituximab was 8%. Although this is an added total survival, it is lower than the absolute survival benefit shown in 2 previous studies— the European GELA (Groupe d’Etudes des Lymphomes de l’Adulte) trial and an observational study conducted in British Columbia.

Using these real-world data, a cost analysis was done after adjusting for incomplete data (because of insufficiently long follow-up time) and discounting the costs by 3% (because of cost differences in different years).

As can be expected, the adjusted 3- year costs were significantly (P >.011) higher for R-CHOP than for CHOP— $77,000 versus $62,000, respectively. The 5-year costs were approximately $87,000 and $70,000, respectively.

In addition, the incremental costs for adding rituximab to the CHOP regimen was approximately $15,000 at 3 years and $16,700 at 5 years. These figures are higher than in premarketing models studied by an American group and in postmarketing simulations in British Columbia. Moreover, the costeffectiveness ratios for R-CHOP were near $100,000 at 3 years and near $50,000 at 5 years.

The team attributes these differences from previous studies to the methodology applied in this study and the use of “real-world data in a real-world setting,” co–lead investigator Murray Krahn, MD, of Cancer Care Ontario, told Value-Based Cancer Care.