Human factors validation study of a disposable autoinjector (Bmab 1200 autoinjector) for subcutaneous delivery of Ustekinumab.

Ustekinumab is approved for treating moderate to severe plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis. The Bmab 1200 autoinjector is a simple, two-step device for subcutaneous ustekinumab biosimilar delivery. This was an in vitro, nonclinical, simulated-use human factors validation study to evaluate if intended users could safely and effectively use it. Ninety participants (recruited via purposive sampling) were enrolled (mean age: 43 years; range: 12-72 years), including adult and adolescent patients, lay caregivers, and healthcare professionals. Without formal training, participants performed simulated injections into foam pads. Test personnel observed, documented, debriefed, and reported any errors made by participants while completing assigned tasks and sub-tasks. Each participant was observed throughout the session and observational and performance data were collected in real time by data logger. Performance measures included injection success rates, use errors, and 24 knowledge tasks. Across these knowledge tasks, participants were required to locate, identify, and understand 28 distinct measures. Participants also provided feedback on usability and confidence levels. All participants (100%) completed unaided dose injections. A total of 20 use errors were documented: hand hygiene (n = 8), site preparation (n = 5), and device handling (n = 7), none causing device damage or failed delivery. The knowledge task success rate was 99.6% (2,511/2,520 measures). Nine use errors (study artifacts or inattention to instructions) occurred only among caregivers. All participants expressed confidence in safe dosing and found the device user-friendly. The Bmab 1200 autoinjector demonstrated high usability and safety across diverse users for ustekinumab biosimilar delivery in chronic autoimmune conditions.