A randomized placebo-controlled double-blinded study comparing oral and subcutaneous administration of mistletoe extract for the treatment of equine sarcoid disease.
Authors: Beermann Anke, Clottu Ophélie, Reif Marcus, Biegel Ulrike, Unger Lucia, Koch Christoph
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Mistletoe Extract for Equine Sarcoid Treatment Equine sarcoids represent the most prevalent skin tumours in horses, and whilst subcutaneous Viscum album extract (mistletoe) has shown promise as a systemic treatment, oral administration routes remain largely unevaluated. Researchers conducted a 14-month, three-armed randomised controlled trial with 45 horses using a double-dummy design to directly compare oral VAE, subcutaneous VAE, and placebo across both delivery routes, measuring changes in sarcoid number and area as the primary endpoint alongside clinical response rates. Although oral VAE demonstrated slightly higher response rates—27% complete regression and 40% complete or partial regression compared to 13% and 25% in the placebo group respectively—these differences failed to reach statistical significance (odds ratio 2.16, P = 0.336), with subcutaneous administration showing similarly non-significant results. The oral formulation proved well tolerated, yet the study provides no robust evidence that either delivery method of mistletoe extract offers meaningful advantage over placebo for systemic sarcoid management, challenging the clinical utility of VAE as a standalone treatment despite its safety profile. Practitioners should exercise caution when recommending VAE therapy to owners and may wish to prioritise established interventions or multimodal approaches until higher-quality evidence emerges.
Read the full abstract on PubMed
Practical Takeaways
- •While oral VAE shows a numerical trend toward benefit in sarcoid treatment compared to placebo, the effect is not statistically significant and should not be relied upon as primary therapy
- •Subcutaneous VAE administration, previously considered efficacious, did not demonstrate superiority over placebo in this rigorous trial, warranting reconsideration of its clinical utility
- •Good tolerability of oral VAE makes it a safe option to discuss with owners, but expectations for therapeutic efficacy should be managed carefully given lack of proven benefit over placebo
Key Findings
- •No statistically significant difference in composite endpoint (ES number and area change) between oral VAE, subcutaneous VAE, and placebo groups after 14 months
- •Complete ES regression occurred in 27% of oral VAE-treated horses versus 13% in placebo group, but this difference was not statistically significant (OR 2.16, 95% CI 0.45-10.42, P=0.336)
- •Clinical response (complete or partial regression) was 40% with oral VAE, 29% with SC VAE, and 25% with placebo
- •Oral mistletoe extract was well tolerated with no safety concerns reported