Use of the Intratumoural Anticancer Drug Tigilanol Tiglate in Two Horses.
Authors: De Ridder Thomas, Ruppin Mick, Wheeless Meagan, Williams Stephanie, Reddell Paul
Journal: Frontiers in veterinary science
Summary
Tigilanol tiglate, a novel intratumoural anticancer agent approved for canine mast cell tumours in Europe, works through a tumour-agnostic mechanism that triggers acute inflammation, immune activation, and vascular disruption—suggesting broader therapeutic potential across species and tumour types. De Ridder and colleagues adapted the drug for equine use by reducing the intratumoural dose by 30% relative to canine protocols and implementing concomitant medications to manage the anticipated inflammatory response, then treated two horses: one with a recurrent fibroblastic sarcoid and one with a periocular squamous cell carcinoma. Both cases showed rapid haemorrhagic necrosis within 24 hours, tumour slough between 6–16 days, and complete re-epithelialisation with good functional outcomes; drug-induced inflammation and oedema were adequately controlled and largely resolved within 3 days, whilst minor lethargy and localised discomfort in the first few days post-treatment were the only notable adverse effects. At follow-up, neither horse showed tumour recurrence (at 93 and 189 days respectively), matching clinical responses observed in canine and human patients. For equine practitioners managing cutaneous neoplasias—particularly aggressive or recurrent lesions unsuitable for surgical excision—this preliminary evidence suggests tigilanol tiglate warrants further clinical evaluation as a potential minimally invasive alternative, though species-specific dosing protocols and careful post-treatment wound management remain essential considerations.
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Practical Takeaways
- •Tigilanol tiglate shows promise as a non-surgical option for cutaneous equine tumors, particularly recurrent sarcoids and squamous cell carcinomas, with complete healing and no early recurrence in these cases
- •Species-specific dosing (reduced 30% from canine dose) with coordinated anti-inflammatory support appears necessary and manageable for equine applications
- •Treatment causes predictable acute inflammation and wound formation; plan for 2-3 weeks healing time and monitor for localized discomfort in first 3-5 days post-injection
Key Findings
- •Tigilanol tiglate at 30% reduced dose (vs. canine protocol) induced haemorrhagic tumor necrosis within 24 hours in both equine cases
- •Complete tumor slough occurred within 6-16 days with full re-epithelialisation and good functional outcome in both cases
- •Concomitant anti-inflammatory medication successfully controlled drug-induced inflammation and oedema, largely resolved within 3 days
- •No tumor recurrence observed at 93 days (sarcoid) and 189 days (squamous cell carcinoma) post-treatment