GvHD prophylaxis – which one is better? Comparison of single-agent post-transplantation cyclophosphamide and calcineurin inhibitors

On Wednesday 21 March 2018 during an oral abstract session at the 44^th Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT), Lisbon, Portugal, Ivan Moiseev of the First Saint Petersburg State Medical University, St. Petersburg, Russia, on behalf of his colleagues presented results from a single-center study which was designed to compare single-agent post-transplantation cyclophosphamide (saPTCy) and calcineurin inhibitors (CNIs) in patients who received matched related bone marrow transplantation (BMT).

In total, 183 patients were enrolled and received BMT from matched related donor, 78 of them received saPTCy, the other 105 control patients received CNI (mycophenolate mofetil or methotrexate). Median follow-up of patients was two years.

Key findings:

• Efficacy

  • Primary graft failure was not significantly different between the saPTCy and the control group: 1.1% vs 1.6%, P = 0.42
  • Engraftment was significantly slower in the saPTCy group than the control group: 24 vs 19 days, P < 0.001
  • PTCy was superior to CNIs in the following parameters:
    • Grade II-IV aGvHD: HR = 0.239 (95% CI, 0.099–0.58), P = 0.002
    • Grade III-IV aGvHD: HR = 0.192 (95% CI, 0.055–0.666), P = 0.009
    • Relapse incidence: HR = 0.519, (95% CI, 0.297–0.893), P = 0.023
    • Overall survival: HR = 0.489 (95% CI, 0.261–0.917, P = 0.03
    • Event-free-survival: HR = 0.571 (95% CI, 0.334–0.976), P = 0.04
    • GvHD-relapse-free survival: HR = 0.493 (95% CI, 0.309–0.786), P = 0.003
  • There was no significant difference found for moderate and severe GvHD and non-relapse mortality (NRM)
    • Moderate and severe cGvHD: HR = 0.898 (95% CI, 0.477–1.69), P = 0.74
    • Non-relapse mortality: HR = 0.384 (95% CI, 0.089–1.437), P = 0.1768

  • Safety

    • Toxicity of BMT was largely equivalent apart from lower incidence of nephrotoxicity after saPTCy: 33% vs 43%, P = 0.008
    • Higher incidence of grade 3-4 mucositis in the saPTCy group was observed: 41% vs 34%, P = 0.02

In conclusion, saPTCy showed superior results to CNIs in prevention of Grade II-IV, Grade III-IV aGvHD and also increased the incidence of relapse. Moreover, patients receiving saPTCy had better overall survival, event-free-survival and GvHD-relapse-free survival.

Key limitations of this study include its single-center retrospective design and a diverse patient group. The speaker concluded that this study demonstrated that saPTCy provides better outcome rates than CNI-based prophylaxis. Doctor Moiseev further added that “these results should be confirmed in the prospective randomized trials.”