Efficacy and Safety of Sevuparin, a Novel Non-Anti-Coagulant Heparinoid, in Patients with Acute Painful Vaso-Occlusive Crisis; A Global, Multicenter Double-Blind, Randomized, Placebo-Controlled Phase 2 Trial (TVOC01)

Background and purpose: There are no currently approved treatments for the vaso-occlusive crises (VOC) associated with sickle cell disease (SCD). In addition to causing pain, vaso-occlusion and the resulting hypoxia cause a reduction in overall life expectancy and increase chronic morbidity. Sevuparin is a novel, non-anticoagulant, low-molecular weight heparin analogue, with a preclinical multi-modal activity profile against VOC relevant targets (i.e. P- and L-selectin, thrombospondin, Von Willebrand factor, fibronectin). Due to its low risk for bleeding side effects, sevuparin can be dosed at levels that were previously unattainable with heparinoids. The present study evaluated whether sevuparin could shorten the time with VOC in hospitalized SCD patients compared to placebo. Patients and methods: This phase II, global, multicenter, randomized, double-blind, placebo-controlled and parallel group clinical trial enrolled patients aged 12 to 50 with a diagnosis of SCD (HbSS, HbSC, HbSβ0-thalassemia, HbSβ+-thalassemia). The study recruited patients across 22 sites in 8 countries (Netherlands, Belgium, Turkey, Oman, Bahrain, Lebanon, Saudi Arabia, and Jamaica). Patients with VOC received sevuparin or placebo (1:1) along with standard of care (SoC) therapy with a requirement for parenteral opioid use. The primary endpoint was time to VOC resolution, measured as the time from IMP start until resolution by fulfilment of the two following criteria: a) freedom from parenteral opioid use (8 ± 2 hours), b) readiness for discharge as judged by the patient or physician (whichever occurred first). In addition to assessing safety, main secondary efficacy measures were related to pain and opioid use. The sample size of 120 VOC resolution events was determined based on an assumed between-arm hazard ratio of 0.60. Results: Overall, 147 subjects were randomized (144 dosed) to sevuparin, n=71 (69); or placebo n=76 (75). The median age of subjects entering the study was 22 years with 72% adults and 62,5 % males. Treatment groups were generally balanced with respect to demographic and baseline characteristics. Sevuparin, infused continuously at 18 mg/kg/day, did not confer any benefit over placebo in the primary endpoint of time to VOC resolution (ITT Cox proportional HR 0.89 (95% CI 0.61-1.30; p = 0.554; Figure 1a), which was also reflected by the secondary endpoint analyses (exemplified in Figure 1b). Most AEs were mild to moderate and transient. The number of SAEs was slight