Elipsis: A longitudinal study of electronic patient-reported outcomes, actigraphy and biomarkers to identify and assess at-home vaso-occlusive crises in adults and adolescents with sickle cell disease

Clinical trials in sickle cell disease (SCD) continue to have challenges achieving clinical endpoints. Most SCD clinical trials have focused on painful vaso-occlusive crisis (VOC) episodes because they are prevalent, debilitating and often lead to medical contact. However with VOC as a clinical endpoint: there are no objective, quantifiable biomarkers of pain; pain may not be specific to VOC; the threshold for medical contact varies between patients; VOCs occurring at home without medical contact are not captured; other components of VOC (e.g., fatigue, functioning) are poorly assessed. We therefore undertook the present non-interventional, longitudinal study to test novel tools for the identification of VOCs occurring in SCD patients with varying degrees of medical contact. During 6 months of evaluation, longitudinal measures of pain, fatigue, function, activity (by actigraphy), clinical laboratory and biomarker samples from SCD patients (+/- hydroxyurea therapy) in steady state to VOC were studied. A novel electronic patient-reported outcome tool (ePRO) enabled patients to self-report daily pain, fatigue, function, and medication use. It was also used to report VOC in real time, triggering an alert to a mobile phlebotomy team. Blood collections were taken within 24 and 48 hours of self-reported VOC onset (either at home, emergency department [ED], or hospital). Follow-up blood samples were collected 2 days after resolution of the VOC. Baseline blood samples were drawn at home every 3 weeks during stable, non-VOC periods. Biomarker assays included leukocyte-platelet aggregates and circulating microparticles measured by flow cytometry, cell adhesion in microfluidic flow-based assays to immobilized vascular cell adhesion molecule or P-selectin, and a panel of soluble adhesion molecules, cytokines, inflammatory mediators and coagulation factors. Patients wore a Phillips Actiwatch Spectrum™ actigraphy device to track sleep and activity. Patient-reported outcomes, activity, and biomarkers on non-VOC days were compared to those on VOC days using a mixed model approach and results are reported as means with 95% confidence intervals (95%CI). Abstract source