Economic Evaluation of Weekly Epoetin Alfa versus Biweekly Darbepoetin Alfa for Chemotherapy-Induced Anaemia: Evidence from a 16-Week Randomised Trial
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Abstract
Introduction: A 16-week, open-label, multicentre, randomised trial of weekly epoetin alfa 40_000 units versus biweekly darbepoetin alfa 200mug among 358 patients with solid-tumour cancers and chemotherapy-induced anaemia demonstrated superior haematological outcomes with epoetin alfa. We sought to compare resource use, costs and clinical outcomes between treatment groups and report the results using a cost-consequences framework. Methods: Pre-specified methods were used to assign costs (US,year2004β5values)tomedicalresourcesandpatienttimeusingasocietalperspective.Costsforinpatientcare,outpatientcareandphysicianserviceswerebasedonUSMedicarereimbursementrates.IndirectcostsassignedtopatienttimespentreceivingstudymedicationwerebasedonthemeanhourlywageintheUS.Inthebaseβcaseanalysis,theaveragewholesalepricewasusedtoassigncoststomedications.Clinicaloutcomesincludedallhaemoglobinlevelsandtransfusionsrecordedthroughoutthetrial.Sensitivityanalyseswereperformedtoevaluatetheimpactofdifferentcostingmethods,costsources,perspectivesandmethodstoassignhaemoglobinvaluesfollowingabloodtransfusion.Results:Overameanfollowβupdurationof11.8weeks,theaveragecostofstudymedicationsandtheiradministrationwasthesinglelargestcomponentoftotalcostsandwassimilarbetweengroups(epoetinalfaUS5979 and darbepoetin alfa US5935,differenceUS44; 95% CI -590, 692). There were no significant differences in the proportions of patients hospitalised (epoetin alfa 24.6%, darbepoetin alfa 22.0%; p_=_0.57). Patients randomised to epoetin alfa experienced more inpatient days, on average, than patients randomised to darbepoetin alfa (2.6 vs 1.6, 95% CI for the difference, 0.07, 2.27). However, with regard to transfusions, patients in the epoetin alfa arm required fewer units of blood than patients in the darbepoetin alfa arm (0.46 vs 0.88, 95% CI for the difference -0.77, -0.08). Mean total costs, comprising costs for study medications and their administration, inpatient care, transfusions, unplanned radiation therapy, haematology and laboratory services, chemotherapy and non-chemotherapy drugs and indirect costs were US149β76intheepoetinalfaarmcomparedwithUS14_101 in the darbepoetin alfa arm, a difference of US875(95US2374 vs $US1520; 95% CI for difference -33, 1955). Assessments of multiple clinical measures demonstrated improved outcomes with epoetin alfa relative to darbepoetin alfa. Conclusion: Most clinical outcome measures suggested greater improvement with epoetin alfa relative to darbepoetin alfa, but most costs for both agents appeared similar. Decision makers must evaluate the differences in costs and efficacy measures that are most relevant from their perspectives.Anaemia, Antineoplastics, Cost-analysis, Darbepoetin-alfa, Epoetin-alfa