Budget impact of switching from an immediate-release to a prolonged-release formulation of tacrolimus in renal transplant recipients in the UK based on differences in adherence

Abstract

Gorden Muduma,1 Isaac Odeyemi,1 Jayne Smith-Palmer,2 Richard F Pollock21Astellas Pharma Europe, Chertsey, UK; 2Ossian Health Economics and Communications, Basel, SwitzerlandBackground and aims: Advagraf is a once-daily prolonged-release formulation of tacrolimus with proven noninferiority to Prograf, a twice-daily immediate-release formulation of tacrolimus, in biopsy-proven acute rejection, graft survival and patient survival in renal transplant recipients. Advagraf is associated with improved adherence compared with Prograf, which may ultimately improve long-term outcomes. The present study assessed the budget impact of switching patients from Prograf to Advagraf in the UK.Materials and methods: A budget-impact model was constructed based on published data on acute rejection, graft failure, and mortality in the UK setting. Patients were assumed to convert from Prograf to Advagraf on a 1:1 milligram:milligram basis. In a study comparing the adherence rates between once-daily versus twice-daily formulations of tacrolimus, the proportion of patients taking the prescribed number of daily doses was 88.2% in Advagraf patients and 78.8% in Prograf patients. The model applied a relative risk of graft failure of 3.47 to nonadherent patients based on data from a 2004 meta-analysis (based on graft-failure rates of 1.3%–40.0% in adherent patients, compared with 6.1%–100% in nonadherent patients). Cost data were taken from the March 2013 British National Formulary and 2012–2013 National Health Service tariff information. The analysis was performed over a 5-year time horizon and future costs were not discounted, in line with International Society for Pharmacoeconomics and Outcomes Research guidelines.Results: Over a 5-year time horizon, the mean cost per patient (including tacrolimus, concomitant immunosuppressive medications, dialysis after graft failure, and treatment for acute rejection) was £29,328 (standard deviation [SD] £2,844) for Advagraf versus £33,061 (SD £3,178) for Prograf. The total cost saving of £3,733 (SD £530) was driven primarily by reduced dialysis costs arising from the lower incidence of graft failure (21.6% with Prograf versus 18.3% with Advagraf) in the larger proportion of adherent patients in the Advagraf arm. In a hypothetical transplant centre of 100 kidney-transplant recipients, this would result in cost savings approaching £375,000 over 5 years.Conclusion: Conversion of renal transplant recipients from Prograf to Advagraf was associated with lower pharmacy and dialysis costs, with the reduction in dialysis costs being driven by improved adherence to Advagraf regimen and the consequent improvement in graft survival.Keywords: tacrolimus, patient adherence, costs and cost analysis, Great Britain