Basiliximab As Treatment for Refractory Acute Graft-Versus-Host Disease: Long-Term Results from a Single Center

Introduction The treatment of steroid-refractory acute graft-versus-host disease (SR-aGVHD) remains a challenge in low-middle income countries like Brazil due to the lack of access to current standard therapies, such as ruxolitinib. Alternatively, basiliximab - an anti-CD25 monoclonal antibody - has presented good response and overall survival rates in previous studies. Here we evaluated the long-term follow-up of a cohort of mostly high-risk SR-aGVHD patients treated with basiliximab in a reference transplant center in Brazil. Objective To analyze the outcomes of response to treatment and survival rates after the use of basiliximab in SR-aGVHD patients. Methods 120 patients with SR-aGVHD grades II-IV received basiliximab from December 1999 to March 2019. The authors reviewed databases and medical records from 92 of them, since 27 were excluded owing to lack of records. The primary endpoints were the overall response rate (ORR) at day 28 and overall survival (OS) rate in five years. Secondary objectives were identifying risk factors for response and survival. The organs involved were: skin (61; 66%); liver (31; 33%) and GI (65; 70%). Patient's characteristics are summarized in Table 1. Results The ORR at day 28 was 51.1% (47/92), including 22.8% (n = 21) complete responses, 28.3% (n = 26) partial responses and 48.9% (n = 45) failures. The median time to achieve the best response was 10 days (range 1-28, SD = 7.87). The overall survival (OS) rate in five years was 37% (95% CI, 28-48%), with a median of 380.5 days (95% CI, 176-1776). Older patients (> 18 years) had lower OS rates in five years when compared to pediatric patients (HR = 2.18, 95% CI 1.25-3.79, p = 0.006). Only 8 individuals experienced relapse, resulting in a disease-free survival (DFS) rate above 90% in one year. The GVHD-free/Relapse-free survival (GRFS) rate was 55% in one year while the cumulative incidence of Non-Relapse Mortality (NRM) was 50%. Conclusions In this cohort of patients with SR-aGVHD, the ORR at day 28 was 51.1%. The GRFS rate was 55% and the OS rate in five years was 37%, even though most of the patients had grade IV aGVHD, which has been previously associated with very poor survival rates. Thus, we conclude that basiliximab is a viable option of therapy for severe refractory acute GVHD in a scenario of limited resources.