An assessment of dose accuracy and injection force of a novel prefilled insulin pen: comparison with a widely used prefilled insulin pen.

Objective: FlexTouch® (FT) (Novo Nordisk A/S, Bagsværd, Denmark) is a new prefilled insulin pen with a novel injection mechanism encompassing no push-button extension at any dose-setting. This study assessed the dose accuracy and injection force of FT compared with the established Next Generation FlexPen® (NGFP) (Novo Nordisk A/S Bagsværd, Denmark).
Research Design and Methods: Dose accuracy was measured at the minimum, medium and maximum doses (FT, 1, 40 and 80 international units (IU) and NGFP, 1, 30 and 60 IU). Injection force was measured during the injection of the maximum dose (FT, 80 IU; NGFP, 60 IU).
Main Outcomes: FT and NGFP delivered insulin accurately and consistently at all doses (mean ± s.d., FT at 1 IU, 0.98 ± 0.07; 40 IU, 39.86 ± 0.33; 80 IU, 79.76 ± 0.64; NGFP at 1 IU, 1.02 ± 0.08; 30 IU, 29.69 ± 0.30; 60 IU, 59.50 ± 0.51). FT had a significantly (p < 0.0001) lower injection force than NGFP.
Conclusions: The study demonstrated that FT and NGFP deliver insulin accurately and consistently at low, medium and high doses. The novel torque spring injection mechanism of FT results in a significantly lower injection force than NGFP and a pen requiring less thumb-pressure to inject insulin may be welcomed by many people with diabetes.