Clinical significance of pre- and 1-year post-transplant serum ferritin among adult transplant recipients

Investigation of biomarkers to predict outcomes in allogeneic hematopoietic stem cell transplantation

BACKGROUND

Various biomarkers have been developed and evaluated to predict the prognosis and complications of allogeneic hematopoietic cell transplantation (HCT). Most previous studies conducted on different biomarkers evaluated single effects such as those associated with inflammation, immunology, iron metabolism, and nutrition, and only a few studies have comprehensively analyzed markers.

OBJECTIVE

The study aimed to survey comprehensive multiple markers prior to HCT and extract those that significantly predict the outcomes.

STUDY DESIGN

A prospective multicenter observational study was performed. (UMIN000013506) Patients undergoing HCT for hematologic diseases were consecutively enrolled. Besides the usual clinical biomarkers, serum samples for extra-clinical biomarkers were collected and cryopreserved before starting the conditioning regimen. A total of 32 candidate biomarkers were selected, 23 from hematology, biochemistry, immunology, nutrition, and iron metabolism, and 9 from composite markers. Based on the area under the curve (AUC) values for survival, promising biomarkers was extracted. Internal validation for these markers was applied based on bootstrap methods. Setting the cut-off values for them, log-rank test was applied and outcomes including overall survival (OS), relapse, and non-relapse mortality (NRM) were evaluated using multivariate analyses. Furthermore, detailed analysis including transplant-related complications and external validation were conducted focusing on C-reactive protein (CRP) to platelet (Plt) ratio.

RESULTS

A total of 152 patients with hematologic malignancies were enrolled from April 2014 to March 2017. CRP, soluble interleukin-2 receptor (IL2R), CRP to albumin (Alb) ratio, CRP to Plt ratio, Plt to IL2R ratio, and IL2R to Alb ratio were identified as promising markers. Internal validation successfully confirmed their reliability of AUC and multivariate analysis demonstrated the statistical significance between the higher and the lower markers. Above all, a higher CRP to Plt ratio was significantly associated with a lower OS (hazard ratio [HR] 2.77; 95% confidence interval [CI] 1.30-5.91; P = 0.008) and higher non-relapse mortality rates (HR 2.79; 95%CI 1.14-6.80; P = 0.024) at 180 days. Furthermore, univariate analysis showed that a higher CRP to Plt ratio was significantly associated with a higher incidence of sinusoidal obstructive syndrome (P < 0.001) and bloodstream infection (P = 0.027). An external validation test confirmed the significance of the CRP to Plt ratio for these outcomes.

CONCLUSION

The multicenter prospective observational study successfully identified significant biomarkers in patients with hematologic malignancies who received HCT. In particular, CRP to Plt ratio was identified as a novel and useful biomarker for predicting transplant outcomes. Further investigations are needed to validate the novel markers, analysis of the pathophysiology, and application to treatment settings other than HCT.

Post-transplant ferritin level predicts outcomes after allogeneic hematopoietic stem cell transplant, independent from pre-transplant ferritin level

Allogeneic hematopoietic stem cell transplantation (HCT) is associated with significant morbidity and mortality. Elevated pre-transplant ferritin level (ferritin^Pre-HCT) is reported to be associated with increased mortality following HCT. The present study attempted to determine whether post-transplant ferritin level (ferritin^Post-HCT) is associated with outcomes post-HCT, especially in the subgroups which developed acute or chronic graft-versus-host disease (GVHD). Out of 229 patients with serum ferritin level measured post-HCT, median ferritin^Post-HCT was 2178 ng/mL. Patients were stratified into low- or high-risk groups using recursive partitioning, based on ferritin^Post-HCT (≤ 3169 vs > 3169 ng/mL) and ferritin^Pre-HCT (≤ 669 vs > 669 ng/mL). Compared to the low ferritin^Post-HCT group, the high ferritin^Post-HCT group had lower 3-year overall survival (OS) (40.0% vs 66.7%, p < 0.001) and higher non-relapse mortality (NRM) (48.6% vs 17.8%, p < 0.001), but no difference in relapse (10.5% vs 19.7%, p = 0.079). Multivariate analysis confirmed ferritin^Post-HCT as an independent prognostic factor for OS (p = 0.001, HR = 2.323) and NRM (p < 0.001, HR = 3.905). However, ferritin^Pre-HCT did not stratify well for OS or NRM. Ferritin^Post-HCT was also found to be an independent prognostic marker for OS and NRM in the subgroups which developed GVHD. In our cohort, high ferritin^Post-HCT levels were significantly associated with decreased OS and increased NRM independent of ferritin^Pre-HCT or GVHD. Additional studies including larger sample sizes and prospective investigation are warranted to clarify the prognostic significance and pathophysiology of pre- and post-transplant hyperferritinemia.

Deferasirox for the treatment of iron overload after allogeneic hematopoietic cell transplantation: multicenter phase I study (KSGCT1302)

The aim of this study was to assess the safety and optimal dose of deferasirox for the treatment of iron overload after allogeneic hematopoietic cell transplantation (HCT). The primary endpoint was the maximum tolerated dose of deferasirox that was determined by the intrapatient dose escalation methods. A total of 16 patients with post-HCT iron overload were enrolled in the study. After excluding one case of early relapse, 15 remained evaluable. Their median age was 42 years (range 22-68). Median time from HCT to deferasirox administration was 9 months (range 6-84). Deferasirox was started at a dose of 5 mg/kg, and the dose was increased to 7.5 and 10 mg/kg every 4 weeks unless there were no grade ≥ 2 of adverse events. Achievement rates of planned medication were 80% in 5 mg/kg (12 of 15), 73% in 7.5 mg/kg (11 of 15), and 60% in 10 mg/kg (9 of 15), respectively. The reasons for discontinuation of the drug were grade 2 of adverse events (n = 4), late relapse (n = 1), and self-cessation (n = 1). None of the patients developed grade ≥ 3 of adverse events or exacerbation of GVHD. Among 11 evaluable cases, mean value of ferritin decreased from 1560 ng/ml pre-treatment to 1285 ng/ml post-treatment. These data suggested that 10 mg/kg of deferasirox may be maximum tolerated dose when given after HCT. Our dose escalating method of deferasirox is useful to identify the optimal dosage of the drug in each patient.

TRIAL REGISTRATION

UMIN000011251.