Predictive factors for treatment-related mortality and major adverse events after autologous haematopoietic stem cell transplantation for systemic sclerosis: results of a long-term follow-up multicentre study

Autologous haematopoietic stem cell transplantation (HSCT) improves survival in systemic sclerosis (SSc) with poor prognosis, but is hampered by treatment-related mortality (TRM).To evaluate event-free survival (EFS), TRM, response to treatment, disease progression and patient characteristics associated with events.All patients treated with HSCT for SSc in The Netherlands until 2017 (n=92) were included. Data on skin involvement (modified Rodnan skin score (mRSS), pulmonary function (forced vital capacity (FVC) and diffusion capacity of the lungs for carbon monoxide (DLCO)), extent of interstitial lung disease on high-resolution CT using Goh scores and left ventricular ejection fraction (LVEF) were collected at baseline, 1, 2 and 5 years. Occurrence of events, defined as death or major organ failure, were collected until 2019. As control, a comparison between patients treated with cyclophosphamide (CYC) and patients with HSCT who participated in the Autologous Stem Cell Transplantation International Scleroderma (ASTIS) trial was performed.Median follow-up was 4.6 years. EFS estimates at 5, 10 and 15 years were 78%, 76% and 66%, respectively. Twenty deaths occurred. Mean FVC, DLCO, mRSS and Goh scores all improved significantly. Disease progression occurred in 22 patients. Frequency of TRM decreased over time and occurred more often in males. Events were independently associated with male sex, LVEF <50% and older age. In ASTIS, patients treated with HSCT (n=23) 7 events occurred versus 13 in the CYC group (n=22).Our data confirm long-term efficacy of HSCT in improving survival, skin and lung involvement in SSc. Male sex, lower LVEF and older age at baseline were identified as risk factors for events.