The Equine Sarcoid (ES) is a widespread disease affecting more than 10 % of the 3-year-old horse population in Switzerland. ES still poses a major therapeutic challenge, as many different treatment techniques exist, but none of them are 100 % successful, especially since high rates of recurrent tumours are observed. Most treatment options only have a local effect on individual sarcoids and are either very complex or impracticable, depending on the number and location of the tumors. Therefore, immunotherapies which take the entire horse system into account are important and interesting strategies in the treatment of sarcoids.
Mistletoe therapy is effective in the treatment of tumours in cats, dogs and horses. In a prospective, placebo-controlled double-blind study the efficacy of the mistletoe extract Iscador® P as first-line treatment in horses affected by sarcoids was significantly demonstrated one year and five years after the start of treatment.
On the one hand, observations to date show that the healing of ES after the end of mistletoe therapy sometimes took more than one year and, therefore, an extension of the duration of therapy appears to be reasonable. On the other hand, mistletoe therapy is injected subcutaneously three times a week for 15 weeks (42 injections), which is frequently cited as a reason for rejection by owners. This raised the question of the possibility of oral administration of Iscador® P, while maintaining the same therapeutic efficacy, which will be investigated in this study.
Like any other type of treatment, mistletoe therapy is not 100 % successful and it is not yet possible to predict the success of the therapy prior to ES treatment. This study will therefore also investigate the potential of microRNAs as diagnostic and therapeutic biomarkers.