Predictors and Outcomes of Dose Reduction of Methotrexate and Cyclosporin Graft-Versus-Host-Disease Prophylaxis Following Allogeneic Haematopoietic Cell Transplantation.

Abstract

Concern regarding dose-related toxicities of methotrexate (MTX) and cyclosporin (CYA) GVHD prophylaxis occasionally lead to dose alterations post allogeneic haematopoietic cell transplant (alloHCT). To clarify causes of MTX and CYA dose alteration and assess impact on patient outcomes including GVHD, relapse, non-relapse mortality (NRM), and overall survival (OS). Analysis of retrospective data was performed in a single tertiary centre of patients who underwent alloHCT for any indication and who received GVHD prophylaxis with CYA and MTX between the years 2011 and 2015. Univariate analysis was conducted using the log-rank test for OS and using competing risk regression for NRM, relapse and GVHD. Fisher exact tests were used to determine if an association existed between each of the pre-transplant variables and MTX alteration. Multivariate models for OS and NRM were constructed using Cox proportional hazards modelling and competing risk regression respectively. 54/196 (28%) had MTX alterations and 61/187 (33%) had CYA alterations. Reasons for MTX alteration included mucositis, renal or liver impairment, fluid overload and sepsis. Causes of CYA alteration were numerous but most commonly due to acute kidney impairment. MTX alteration was associated with inferior OS (HR 2.4, P=<0.001) and higher NRM (OR 4.6, P<0.001) at 6 years(y) post-landmark. CYA alteration was associated with greater NRM (OR 2.7, P= 0.0137) at 6y. GVHD rates were unaffected by dose alteration. Our findings suggest dose alteration in MTX and CYA GVHD prophylaxis is associated with adverse survival outcomes in alloHCT, without a significant impact on GVHD rates. This article is protected by copyright. All rights reserved.