Genotype-guided thiopurine dosing does not lead to additional costs in patients with inflammatory bowel disease.
J Crohns Colitis. 2019 Jan 30;:
Authors: Sluiter RL, van Marrewijk C, de Jong D, Scheffer H, Guchelaar HJ, Derijks L, Wong DR, Hooymans P, Vermeulen SH, Verbeek ALM, Franke B, van der Wilt GJ, Kievit W, Coenen MJH
Background and aims: Decreased thiopurine S-methyltransferase (TPMT) enzyme activity increases the risk of hematologic adverse drug reactions (ADR) in patients treated with thiopurines. Clinical studies have shown that in patients with inflammatory bowel disease (IBD), pharmacogenetic TPMT-guided thiopurine treatment reduces this risk of ADR. The aim of this study was to investigate, whether this intervention impacts on healthcare costs and/or quality of life.
Methods: An a priori defined cost-effectiveness analysis was conducted in the Thiopurine response Optimization by Pharmacogenetic testing in Inflammatory bowel disease Clinics (TOPIC) trial, a randomized controlled trial performed in 30 Dutch hospitals. Patients diagnosed with IBD (age ≥18 years) were randomly assigned to the intervention (i.e. pre-treatment genotyping) or control group. Total costs in terms of volumes of care, and effects in Quality-Adjusted Life Years (QALYs), based on EuroQol-5D3L utility scores, were measured for 20 weeks. Mean incremental cost savings and QALYs with confidence intervals were calculated using non-parametric bootstrapping with 1000 replications.
Results: The intervention group consisted of 381 patients, the control group had 347 patients. The mean incremental cost savings were €52 per patient (95% percentiles -682, 569). Mean incremental QALYs were 0.001 (95% percentiles -0.009, 0.010). Sensitivity analysis showed that results were robust for potential change in costs of screening, costs of biologicals, and costs associated with productivity loss.
Conclusions: Genotype-guided thiopurine treatment in IBD patients reduced the risk of ADR among patients carrying a TPMT variant, without increasing overall healthcare costs and resulting in comparable quality of life, as compared to standard treatment.
PMID: 30698675 [PubMed – as supplied by publisher]