An Open-Label Tolerability and Actual-Use Human Factors Study of Etrolizumab Autoinjector in Healthy Volunteers

Introduction Etrolizumab is a novel, dual-action, anti-β7 integrin antibody in development for patients with moderate to severe ulcerative colitis or Crohn’s disease. Phase 3 studies use a prefilled syringe (PFS) for etrolizumab administration. In parallel, an autoinjector (AI) is being developed to increase delivery options for patients if etrolizumab is approved. Here we describe the overall development strategy and detail the first-in-human study of this AI. Methods This open-label study of healthy volunteers evaluated the tolerability and usability of the etrolizumab AI under development. The primary endpoint was the proportion of participants with greater than mild pain following injection. Adverse events (AEs) and usage errors were also assessed. Results were reported by injection site (thigh vs abdomen) and needle training (experienced vs naive). Pharmacokinetic (PK) variability between participants was an exploratory endpoint. Results Thirty participants completed the study; 97% of them did not experience any pain greater than mild, and 50% did not experience any pain at all. Three usage errors were observed, one of which resulted in delivery of a partial dose of etrolizumab. No patterns of usage errors were observed. Mild injection site reactions (ISRs) were reported; all resolved by the end of the study. Participants injecting into the abdomen reported more ISRs than those injecting into the thigh; needle training did not influence AE incidence or severity. Conclusions Results from this first-in-human study demonstrate that single injections of etrolizumab 105 mg using an AI were well tolerated in healthy volunteers, with transient, mild pain and minimal usage errors. Results from this study also informed the design of a subsequent PK comparability study evaluating exposure of etrolizumab administered by either the PFS or the AI. Overall, the availability of an AI may provide an attractive option for patients desiring a convenient, easy-to-use delivery mechanism for etrolizumab. Trial Registration NCT02629744