DX08
Rebismart Pressure Profile Accessories Can Reduce Injection Site Pain
Injection pain may comprimise treatment adherence in patients with multiple sclerosis (MS). RebiSmart® is the first electronic auto-injector for subcutaneous interferon beta-1a (IFN) treatment of relapsing MS and was designed to reduce several barriers to optimal treatment adherence. However, a minor proportion of patients still experience injection pain. The RebiSmart® electronic autoinjector is not currently approved by the US Food and Drug Administration for use in the US.
Objectives:
We evaluated 4 types of pressure profile accessories used in conjunction with RebiSmart® for their effect on reducing perceived pain at the injection site. Pressure profiles are detachable plastic accessories with geometric protusions that are concentrated around the needle injection site. Application of the accessories on the skin stimulates large sensory nerve fibres to block the transmission of slower small diameter pain nerve fibres. Here we present the optimal pressure profile accessory.
Methods:
We conducted a single centre, single-blind, randomized, 5-treatment, 5-sequence, crossover exploratory study to determine which pressure profile accessories can reduce pain perception. Ten healthy subjects evaluated the pain associated with subcutaneous injections using 4 variations of pressure profile accessories used in conjunction with the RebiSmart®, and one control injection (RebiSmart® only). Pain scores were assessed immediately after injection using a validated 100mm Visual Analogue Scale (VAS). The usability of each pressure profile prototype was also evaluated.
Results:
Six out of 10 healthy subjects met the pre-specified definition of subjects who had a low tolerance of pain (VAS with RebiSmart® alone >30mm). These subjects rated a mean (STDev) reduction in injection pain of 15mm (22mm) on VAS absolutely, or 22% relatively, using the optimal pressure profile accessory compared to RebiSmart® alone. Furthermore, the 4 subjects that responded to the optimal pressure profile accessory had a greater average pain reduction of 27mm (17mm) on VAS absolutely, or 39% relatively, compared to RebiSmart® alone. The majority of subjects rated the usability as easy or very easy, and 10 out of 10 subjects rated the assembly and disassembly of the accessories acceptable.
Conclusions:
Based on this preliminary study, RebiSmart® pressure profile accessories can reduce injection site pain in healthy subjects who have a low tolerance to injection pain. The accessories are easy to use and their effectiveness may further enhance treatment adherence for MS patients. Further investigation in MS patients is warrented.