Cost-effectiveness of rituximab maintenance therapy for patients with follicular lymphoma: The Spanish perspective

Abstract

8092 Background: In patients with relapsed or refractory follicular lymphoma (FL) who attain a response with either cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) alone or Rituximab + CHOP, maintenance treatment with Rituximab has shown to significantly improve overall survival (OS) (85% at 3 years vs. 77%, p=0.011) and progression free survival (PFS) (51,5 vs. 14.9 months, p<0.001) as compared to observation alone (OA). We analyzed the cost-effectiveness, from a Spanish perspective, of Rituximab maintenance therapy (375mg/m2 every 3 months until progression or for 2 years) versus OA according to the population and data described for the European Organization for Research Treatment of Cancer (EORTC) 20981 study (van Oers MHJ Blood 2006). Methods: Incremental cost-effectiveness was assessed through a deterministic, three health states model (disease-free, progression and death) transition model. Base case model: PFS and OS were extrapolated from EORTC 20981 data using a Weibull distribution, Rituximab maintenance benefit was assumed to last 5 years, 10 years time horizon, 3.5% discount rate on costs and benefits, and Spanish National Health Service perspective (direct costs only). Resource use was estimated from a Spanish expert panel and EORTC 20981 study. Unit costs were obtained from local databases (May 2006 €). Health states utility values were derived from an ad hoc study. Sensitivity analyses were performed for all mentioned variables. Results: For the base case, more quality-adjusted life years (QALY), life-years (LY) and progression-free survival years per patient on maintenance therapy were obtained versus OA (incremental values of 0.85, 0.94 and 1.46, respectively). Total cost per patient was higher with Rituximab than with OA (+8,026€). Incremental cost per QALY gained was 9,358€, with a cost per LY gained of 8.493€ and a cost per PFS year gained of 5,485€. In the sensitivity analysis, values ranged between 7.263€ and 22.160€ per QALY gained. Conclusions: This study confirms that in patients with relapsed /refractory FL who attain a response with further therapy, maintenance treatment with Rituximab compared to observation alone is cost-effective. No significant financial relationships to disclose.