Usability of the Ranibizumab 0.5 mg Prefilled Syringe: Human Factors Studies to Evaluate Critical Task Completion by Healthcare Professionals.

PURPOSE: A ranibizumab prefilled syringe (PFS) has been approved by the U.S. Food and Drug Administration. Here we evaluate the use of the ranibizumab PFS for intravitreal injection by assessing whether the PFS enables healthcare providers to successfully prepare and administer an injection without prior training. DESIGN: Simulated-use and actual-use human factors usability studies. PARTICIPANTS: Retina specialists and ophthalmic medical personnel. METHODS: In a simulated-use summative usability study, retina specialists (n = 15) and ophthalmic medical personnel (n = 15) prepared the ranibizumab PFS and performed injections into a model eye. In an actual-use formative usability study (ClinicalTrials.gov identifier: NCT02698566), three assistants and three retina specialists prepared the PFS and performed intravitreal injections, respectively, in study eyes of patients with retinal diseases (n = 35). MAIN OUTCOME MEASURES: Twelve tasks specific to the unpacking, preparing, and properly administering the PFS for intravitreal injection were evaluated by a study assessor. Task performances were evaluated for use errors, close calls, and operational difficulties. Post-injection subjective user evaluations were performed to assess ease of use. RESULTS: All participants successfully performed all essential and safety-critical tasks without use error in both the simulated-use and actual-use human factors usability studies. The majority of participants rated the tasks required to use the ranibizumab PFS as "Easy" or "Very Easy." CONCLUSIONS: Both the simulated-use and actual-use usability studies yielded consistent data, showing that healthcare professionals are able to use the ranibizumab PFS by successfully performing all critical tasks involved in preparing and delivering an intravitreal injection. The simulated-use usability testing was sufficiently realistic and representative of real-world use, and was appropriate and preferred over actual-use usability testing for proper evaluation of the product user interface.LAY ABSTRACT: Ranibizumab is approved in the United States to treat various eye conditions, including neovascular (wet) age-related macular degeneration, macular edema following retinal vein occlusion, diabetic macular edema, diabetic retinopathy, and myopic choroidal neovascularization. It is administered as an injection into the eye once a month, and is available in a vial from which medication needs to be withdrawn using a standard syringe with a 19-gauge filter needle. The filter needle is then replaced by a smaller gauge needle for the intravitreal injection. The recent U.S. Food and Drug Administration approval of a 0.5 mg ranibizumab prefilled syringe eliminates the need for withdrawing medication from a vial and changing needles prior to use. The studies described in this report assessed the usability of the ranibizumab prefilled syringe by retina specialists and ophthalmic medical personnel in simulated- and actual-use settings. Twelve tasks that included unpacking, preparing, and properly administering the prefilled syringe for intravitreal injection were evaluated by a study assessor. Task performances were evaluated for use errors, close calls, and operational difficulties. Participants successfully performed all the tasks without any critical errors in both simulated-use and actual-use human factors usability studies, and most participants found the syringe to be "Easy" or "Very Easy" to use.

Differential effects of x-rays and high-energy 56Fe ions on human mesenchymal stem cells.

PURPOSE: Stem cells hold great potential for regenerative medicine, but they have also been implicated in cancer and aging. How different kinds of ionizing radiation affect stem cell biology remains unexplored. This study was designed to compare the biological effects of X-rays and of high-linear energy transfer (LET) (56)Fe ions on human mesenchymal stem cells (hMSC). METHODS AND MATERIALS: A multi-functional comparison was carried out to investigate the differential effects of X-rays and (56)Fe ions on hMSC. The end points included modulation of key markers such as p53, cell cycle progression, osteogenic differentiation, and pathway and networks through transcriptomic profiling and bioinformatics analysis. RESULTS: X-rays and (56)Fe ions differentially inhibited the cell cycle progression of hMSC in a p53-dependent manner without impairing their in vitro osteogenic differentiation process. Pathway and network analyses revealed that cytoskeleton and receptor signaling were uniquely enriched for low-dose (0.1 Gy) X-rays. In contrast, DNA/RNA metabolism and cell cycle regulation were enriched for high-dose (1 Gy) X-rays and (56)Fe ions, with more significant effects from (56)Fe ions. Specifically, DNA replication, DNA strand elongation, and DNA binding/transferase activity were perturbed more severely by 1 Gy (56)Fe ions than by 1 Gy X-rays, consistent with the significant G2/M arrest for the former while not for the latter. CONCLUSIONS: (56)Fe ions exert more significant effects on hMSC than X-rays. Since hMSC are the progenitors of osteoblasts in vivo, this study provides new mechanistic understandings of the relative health risks associated with low- and high-dose X-rays and high-LET space radiation.