Safety and efficacy of mistletoe extract (Viscum album) Iscador (R) P in the treatment of equine sarcoid - a prospective, randomized, controlled, double-blind study.

Summary

Background:
So far a therapy of the Equine Sarcoid (ES), a semi malignant skin tumor of equids is hardly considered as efficient. Furthermore, Sarcoids can be found as multi-focal typus or in critical localizations where success of surgical interventions is potentially very limited. Goal of this clinical trial was to evaluate in context of a prospective, randomized, controlled, double-blind study, the safety and efficacy of the Mistletoe extract (Viscum album) Iscador® P as a primary therapy of Equine Sarcoid.
Methods: 53 horses with the histologically confirmed diagnosis ES became randomly assigned Verum (V; n=32) or Control (C; n=21). The horses received rising dosages of Iscador® P from 0.1mg to 20 mg extract/dose or physiological NaCl solution 3 times a week over 105 days s.c. The number, localization and morphology of the ES were observed and documented over 12 months.
Results: In the Verum Group, 13 horses (41%) showed an improvement (at least 50% tumor remission). Of these cases a number of 9 patients developed a complete cure (28%). In the Control Group only 3 cases (14%; all showing complete cure) were classified as improved (p<0.05). While in horses with oligo-focal ES (1-2 per animal) no clear difference between Verum and Control could be found, a significant better therapy course appeared after treatment by Verum of horses with more than 2 ES: a number of 12 of 25 horses (48%) showed an improvement, 9 of these a complete remission (36%) including ES localized at the critical areas (head and around the eyes). In comparison, in the Control group only 1 of 15 cases (6%) could be classified as improved in this class.
As side effects of the ISCADOR injections in 10 cases a slight swelling could be observed which decreased spontaneously within few days.
Conclusions: Iscador® P represents a safe and efficient therapy alternative in Equine Sarcoids, especially in cases with multi-focal character. In tumors grown in problematic localizations an attempt with mistletoe therapy should be conducted to avoid the risk of damage the intact surrounding tissue, particularly in the eye area.