COST OF THERAPIES TO INDUCE REMISSION IN PATIENTS WITH WEGENER'S GRANULOMATOSIS

Purpose: Wegener’s granulomatosis (WG) is a rare blood vessel disease, fatal without therapy (1 year mortality: 80%). Cyclophosphamide and glucocorticoids, the standard of care to induce remission, are associated with severe side-effects (infections, infertility, malignancies…).  In France, intravenous cyclophosphamide (IVCYC) is recommended in first intention and oral cyclophosphamide (ORCYC) in second, whereas it is the reference therapy in USA. Rituximab, mainly used for treating B-cell lymphomas, has recently been used as salvage therapy in treating autoimmune diseases. As a chronic disease, WG management is in France entirely reimbursed to patients by healthcare insurance. Recently, a non inferiority clinical trial found rituximab as effective as ORCYC in inducing remission. To estimate from a societal viewpoint the costs of 6 months therapy to induce remission in a ‘base case’ patient (53 years old patient affected by severe WG) treated with ORCYC, IVCYC or rituximab.

Method: The database of inpatient stays in a French Hospital during 2009 was analyzed to identify stays required for WG management (type, length and cost of stays). To evaluate the cost of patients’ treatment during 6 months, therapies, protocols and regimens followed were those recommended by healthcare authorities and experts. Our analysis included costs of drugs, hospital stays in public hospitals and treatment of severe pneumonia (the most frequent side-effect). As IV drugs are administrated to inpatients, their costs are included in those of hospital stays except for rituximab classified in the high cost drug list. Non medical costs (i.e. transports and sick pay received by patients during unemployment) were also evaluated.

Result: The average remission-induction therapy costs 19,134€ with ORCYC, 24,217€ with IVCYC and 28,653€ with rituximab. ORCYC is less costly because of less hospital stays needed. Rituximab is the most expensive mainly due to the price of injections higher than IVCYC injections (1674 euros vs. 10 euros).

Conclusion: We could evaluate the average cost of three strategies to induce remission in a base case patient with WG. Rituximab strategy is the highest. The route of administration and the price of drugs are prominent. Therefore, currently, rituximab could be used when cyclophosphamide is contraindicated and in refractory patients where it seems to be more effective. Long term data on remission duration and relapses are expected to evaluate the cost-effectiveness of rituximab.