Time to resolution of veno-occlusive disease/sinusoidal obstruction syndrome post-HCT in defibrotide-treated adults from two European registries

We report a pooled analysis of real-world data of adult patients from two European registries of defibrotide use (DEFIFrance and EBMT Post-Authorization Safety Study [EBMT PASS]) to provide insights into the duration of defibrotide therapy to achieve resolution of veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) symptoms by severity. Overall, 275 defibrotide-treated adults with VOD/SOS post-hematopoietic cell transplantation (HCT) were included (severe VOD/SOS, n = 215; nonsevere VOD/SOS, n = 60). Median time from the start of defibrotide treatment to VOD/SOS resolution was 18.5 and 16.5 days in patients with severe and nonsevere VOD/SOS, respectively. Among patients with VOD/SOS resolution, symptoms resolved after >21 days in 31% ( n = 40/128) and 32% ( n = 14/44) with severe and nonsevere VOD/SOS, respectively. In all patients with VOD/SOS resolution independent of severity ( n = 174), the Kaplan-Meier–estimated survival at Day 100 post-HCT was 82% (95% confidence interval [CI]: 75%, 87%); this was 78% (95% CI: 70%, 84%) and 91% (95% CI: 78%, 96%) in patients with severe and nonsevere VOD/SOS, respectively. Serious treatment-emergent adverse events of interest occurred in 31% of patients with VOD/SOS resolution. This pooled analysis supports the utility of defibrotide treatment for VOD/SOS and highlights that treatment may often need to be continued beyond 21 days to achieve resolution.