Optimizing Patient Selection for Reduced Nonrelapse Mortality After Reduced-Intensity Conditioning: A CIBMTR Analysis

Reduced-intensity conditioning (RIC) is generally associated with lower nonrelapse mortality (NRM) but higher relapse risk compared to myeloablative conditioning (MAC) in allogeneic hematopoietic cell transplantation (HCT). The Risk assessment for the Intensity of Conditioning regimen in Elderly patients (RICE) score, developed using a large Japanese cohort, was designed to identify patients likely to benefit from reduced NRM with RIC. It is calculated based on three factors: advanced age, high comorbidities, and use of umbilical cord blood donor.

In this study, we evaluated the applicability of the RICE score in a Western population using a publicly available CIBMTR dataset.

This study included 2595 patients aged 40 to 65 years with AML and MDS who underwent their first HCT between 2009 and 2015. The primary endpoint was NRM, stratified by conditioning intensity and RICE score.

Among patients with a low RICE score, MAC was associated with similar NRM (HR, 0.86; 95% CI, 0.70 to 1.06; P = .150) but lower relapse, resulting in improved disease-free survival (DFS). In contrast, among patients with a high RICE score, NRM was significantly lower with RIC compared to MAC (HR, 0.69; 95% CI, 0.48 to 0.99; P = .048), while DFS was similar due to a higher relapse rate with RIC.

This study provides external validation of the RICE score in a Western cohort and suggests its potential to inform conditioning-intensity selection based on individual patient characteristics. This simple, data-driven tool may help accurately assess the risk of NRM associated with conditioning intensity and improve transplant outcomes across diverse populations.