CT-195 Predictive Value of ST2, REG3a, and MAGIC Algorithm in Haploidentical Transplantation With Post-Transplant Cyclophosphamide Outcomes

Abstract

Recent studies have described protein biomarkers in peripheral blood associated to allogeneic-stem-cell transplantation (allo-SCT) outcomes. To date, two studies have focused on haploidentical allo-SCT with post-transplant cyclophosphamide (haplo-SCT-PTCy). These works evaluate ST2 and REG3α at days +15 and +30 but do not include the analysis of the MAGIC algorithm. Analyze ST2, REG3a, and MAGIC algorithm early weekly after haplo-SCT-PTCy and its association with transplant outcomes. Prospective study with 151 consecutive patients who underwent haplo-SCT-PTCy at University Hospital of Salamanca (2012-2020). Serial serum samples were collected on days 0, +3, +7, +14 and +21 in 81 patients. ST2 and REG3a serum concentration was established by Luminex XMap. Median luminescence levels between groups were compared using Wilcoxon-Mann-Whitney test. Cut-off points for each cytokine were estimated using Cutoff-Finder application in R. MAGIC algorithm was determined from the ST2 and REG3α values. Log-rank was used to compare survival curves. Multivariable analyses were carried out with Cox regression, including the most significant clinical variables. Recipient median age of 50 years, 73% of transplants were performed with reduced-intensity conditioning. Median follow-up of 35 months. Higher levels of ST2 were associated with higher NRM 1-year (0, +7, +14), lower OS 2-years (+7, +14), and GRFS 2-years (+14, +21). Higher levels of REG3α were associated with higher NRM 1-year (0, 7, 14, 21), lower OS 2-years (0, +7, +14, +21) and lower GRFS-2y (+14). Similarly, the analysis of MAGIC algorithm in univariate analysis distinguished two statistically significant risk groups for GRFS (+14), OS (0, +14), and NRM 1-year (0, +14). On multivariate analysis, OS was independently associated with HCT-CI ≥3, ST2 (0, +7, 14, +21), REG3α (0, +14, +21) and MAGIC (0, +14), NRM with ST2 (0, +14), REG3α (14) and HCT-CI ≥3. ST2 (+7, +14, +21) REG3α (+14), MAGIC (+14) and HCT-CI ≥3 were the only variables associated to GRFS. These results confirm the prognostic impact of ST2, REG3α in haplo-SCT-PTCy early on days +7 and +14 for OS, NRM and GRFS endpoints. Confirms the identification using the MAGIC algorithm of two risk groups in a homogeneous series of haplo-SCT-PTCy. Standardization in prospective and larger series is still required.