Correlation Between Severity of cGvHD and Transplant Outcome: A Retrospective Monocenter Study Based on NIH Classification,
Authors: Saillard Colombe , Crocchiolo Roberto , Furst Sabine , El-Cheikh Jean , Castagna Luca , Oudin Claire , Faucher Catherine , Claude Lemarie , Chabannon Christian , Granata Angela , Blaise Didier 
Published: October 2019

Abstract
Abstract 4088

Background:
Chronic graft-versus-host disease (cGvHD) after allogeneic hematopoietic stem cell transplantation (HSCT) for hematological malignancies is associated with lower relapse rate, due to graft-versus-tumor effect. We know that the extensive form is associated with higher transplant-related mortality after myeloablative conditioning regimen, mainly due to infectious complications as a consequence of immunosuppressive treatment. Beside the “classical” Seattle classification (limited or extensive form), a recent classification (from National Institute of Health, NIH) distinguishes three levels of severity: limited, moderate and severe. We compare here both classifications for patients receiving reduced-intensity conditioning (RIC) transplant and looked for any association of cGvHD severity with transplant outcome.

Patients and Methods:
We evaluated data on all adult patients with hematological lymphoid or myeloid malignancies who received HSCT from related or unrelated donor, using peripheral blood stem cells, after RIC regimens (with fludarabine-busulfan-ATG) between 1998 and 2010 at the Institut Paoli-Calmettes (Marseille, France). Data on main pre- and post-transplant variables were collected; cGvHD was classified according to its presentation and severity (with both Seattle and NIH classifications) and was correlated with overall survival (OS), non relapse mortality (NRM), and relapse. cGvHD was considered as time-dependent variable, and was included in uni- and multivariate models, after adjusting for age, disease risk, HLA compatibility, graft source and comorbidity score. Relapse or death before cGvHD was considered as a competing event.

Results:
283 patients were evaluated, 121 have developed cGvHD (27 limited forms and 94 extensive forms), 162 have not, for an incidence rate of 10% and 33% of limited and extensive forms respectively. Median follow up was 607 days, patients had a median age of 50 years, transplanted for acute leukemia (55), lymphoma (78), multiple myeloma (49), myelodysplastic syndrome (24), CLL (12), CML (16) or others malignancies (19). Peripheral stem cells were mostly used (294 versus 20 bone marrow graft). We had 241 related donors and 77 unrelated donors. The median day of cGvHD occurrence was 132, we found 52 de novo forms, 40 quiescent and 26 progressive forms.
After reclassification with NIH criteria, we obtained 28 mild, 52 moderate and 41 severe forms. 22 of 27 limited forms were classified as mild, the extensive forms were divided into 49 moderate and 39 severe forms. In multivariate analysis, mild and moderate forms were associated with better OS compared with other groups. Severe cGvHD was associated with significant increase in NRM. Among the other variables, only age was statistically significative in OS and NRM models. Although the incidence of relapse was lower in patients with cGvHD compared with those without, no significant difference was seen between the 3 groups of patients presenting it.

Conclusion:
Following a fludarabine-busulfan-ATG RIC, it seems that mild to moderate cGVHD forms are associated with better OS than patients without or with severe cGVHD. This is related to lower NRM than patients with severe cGVHD and at least a comparable antitumoral effect with respect to patients without cGVHD. This invites developing strategies limiting severity but not abrogating the effect of cGVHD.

Disclosures:
No relevant conflicts of interest to declare.