Pilot Study of a Topical Adhesive Containing Anesthetic and Heating Components to Reduce Injection Pain with Subcutaneous Multiple Sclerosis Medications

Background: Injection pain and fear of pain ("needle phobia") are common problems that limit adherence to injection of subcutaneous (SC) medications for treating multiple sclerosis (MS).  Relieving injection site pain may improve the tolerability of MS medications.  SYNERA™ is a peel-and-stick topical adhesive (S-TA) with a novel heating component designed to enhance the delivery of an anesthetic mixture of lidocaine and tetracaine.  This adhesive is approved in the USA for use in dermal analgesia for venous access and superficial dermatological procedures and may be useful in reducing MS drug injection pain and needle phobia.

Objectives: To determine the effect of S-TA  on immediate pain following injection and other measures of comfort with SC MS drug injection and to determine the preferred period of application (30 to 60 minutes) prior to injection.  

Methods: Thirty subjects with MS taking SC interferon beta (IFNB) or glatiramer acetate (GA) and having injection pain rated 3 or higher on 0-10 visual analog scale (VAS)  are being enrolled in an open-label prospective study.   Subjects will complete injection diaries.  S-TA is applied prior to drug injection, initially for 60 minutes and sbsequently for 30 minutes to assess differences based on time of application.  The study duration is 3-6 weeks (1-2 weeks of baseline observation followed by 2-4 weeks of on-drug observation), depending on which MS drug product the subject is taking.  The primary outcome measure is immediate pain upon injection (0-10 VAS).  Secondary measures will include fear of injection, 12 and 24-hour ratings of pain by VAS and 24-hour local injection site reaction scale (LISR) score.  Statistical analysis (t-test or equivalent non-parametric method) will assess mean values on and off study drug and for comparing 30 vs. 60 minute applications. 

Results: At this writing, 28 subjects are active (N=2) or have completed (N=26) the study.  The number on IFNB = 4 and GA = 24.  The average age = 54 years, average EDSS = 4.0, percent female = 86%.  Average baseline ratings for pain on 0-10 VAS = 5.9 (immediate), 2.9 (12hr), 2.2 (24hr); baseline Fear of Injection = 3.9 (0-10 VAS) and LISR = 2.9 (0-6 scale).  Two treatment related adverse events have been recorded: muscle spasm and lightheadedness (N=1, subject withdrew) and mild dermatitis (N=1, completed). 

Conclusions: Final results will be presented at the Consortium meeting, including Pain and Fear of Injection ratings, analyses of 60 vs 30 minute applications and global impressions. This study explores the clinical utility of a topical adhesive containing anesthetic and heating components in managing subcutaneous medication injections used for MS treatment.