Methotrexate and citrovorum factor after histoincompatible allogeneic bone marrow transplants in dogs

Role of folinic acid in methotrexate-based prophylaxis of graft-versus-host disease following hematopoietic stem cell transplantation

Methotrexate (MTX) is one of the main therapeutic agents currently used for the prophylaxis of graft-versus-host disease (GvHD) following hematopoietic stem cell transplantation. However, it is associated with significant toxicity and considerable side effects in many patients, which lead to either early withdrawal or dose reductions that may expose patients to the risk of GvHD and graft failure. Folinic acid (FA) can bypass the inhibitory effects of MTX on folate availability and control MTX toxicity. However, concerns that FA might inhibit the anti-GvHD effect of MTX and limited reports on its clinical usefulness have led to reluctance in its inclusion in standard GvHD prophylaxis regimens. Additionally, universal dosing and timing guidelines are lacking. I discuss the available literature and evaluate the evidence for the effect of FA on MTX toxicity and its safety regarding GvHD development and graft rejection in both adult and pediatric patients. Although FA administration appears to be safe, its efficacy for routine use in all types of transplants in adult patients is unproven and further research is required to confirm its MTX toxicity-lowering effect, identify the individual parameters that influence its usefulness in clinical practice, and evaluate its potential when developing a personalized prophylaxis regimen.

Efficacy of folinic acid rescue following MTX GVHD prophylaxis: results of a double-blind, randomized, controlled study

The use of methotrexate (MTX) for graft-versus-host disease (GVHD) prophylaxis is associated with increased rates of organ-specific toxicities. Despite limited data, the European Society for Blood and Marrow Transplantation-European LeukemiaNet working group recommend the use of folinic acid (FA) rescue to reduce MTX toxicity after allogeneic hematopoietic cell transplantation (allo-HCT). In a multicenter, double-blind, randomized, controlled trial, we explored whether FA rescue reduces MTX-induced toxicity. We enrolled patients undergoing allo-HCT with myeloablative conditioning with peripheral blood stem cell grafts, with GVHD prophylaxis consisting of cyclosporine and MTX. Patients were randomized to receive FA or placebo starting 24 hours after each MTX dose and continuing over 24 hours in 3 to 4 divided doses. The primary end point was the rate of grades 3 and 4 oral mucositis. After enrollment of 52 patients (FA, n = 28; placebo, n = 24), preplanned interim analysis revealed similar rates of grade 3 and 4 (46.6% vs 45.8%; P = .97) and grades 1 to 4 (83.3% vs 77.8%; P = .65) oral mucositis. With a median follow-up of 17 (range, 4.5-50) months, there was no difference in the rates of acute and chronic GVHD, disease relapse, nonrelapse mortality, and overall survival. These interim results did not support continuation of the study. We conclude that FA rescue after MTX GVHD prophylaxis does not decrease regimen-related toxicity or affect transplantation outcomes. This study was registered at clinicaltrials.gov as #NCT02506231.

Cyclosporin A versus methotrexate, followed by rescue with folinic acid as prophylaxis of acute graft-versus-host disease after bone marrow transplantation

Fifty-seven patients undergoing bone marrow transplantation were randomly assigned to receive either cyclosporin A (CsA, n = 26) or methotrexate, followed by rescue with folinic acid (MTX + FA, n = 31) as prophylaxis for graft-versus-host disease (GVHD). All patients but one receiving CsA had evidence of sustained engraftment, and there was no difference between the two groups on the day in which marrow engraftment was documented. Oropharyngeal mucositis was of similar incidence and severity in the two groups. In contrast, patients receiving CsA showed higher renal and hepatic toxicity rates than those treated with MTX + FA. Severe-to-moderate acute GVHD (grades II-IV) was documented in 12 patients receiving CsA and in 12 treated with MTX + FA. The cumulative incidence of this complication was similar in both groups (46.1% and 38.7%). Similarly, there was no difference in the incidence of chronic GVHD. The leukemic relapse rates were also comparable, as well as the estimated probability of survival, which was 55% in patients treated with MTX + FA and 41% in those who were given CsA. We conclude that MTX + FA is as effective as CsA in the prevention of GVHD, with the additional advantage of reduced renal and hepatic toxicities.