Intratumoural tigilanol tiglate in the multicentre treatment of equine sarcoids and cutaneous melanomas.
Authors: Labens, Saba, Williams, Hollis, Ensink, Jose-Cunilleras, Jordana-Garcia, Bergvall, Ruppin, Condon, Spelta, Elce, De Ridder, Morton, McGee, Reddell
Journal: Equine veterinary journal
Summary
# Tigilanol Tiglate for Equine Sarcoids and Cutaneous Melanomas: A Multicentre Clinical Assessment Intralesional injection of tigilanol tiglate (TT)—a plant-derived molecule from the Australian rainforest plant *Fontainea picrosperma*—represents a promising addition to the limited arsenal of treatments for equine cutaneous neoplasia, with established efficacy in canine mast cell tumours. This multicentre prospective trial evaluated TT's effectiveness across 41 sarcoids and 97 melanomas treated with dose-volume-adjusted injections (0.35 mg/cm³ for sarcoids; 0.2 mg/cm³ for melanomas, maximum 2 mg per lesion). Complete tumour volume regression occurred in 73% and 74% of sarcoids and melanomas respectively, though full clinical response—defined as complete regression with expert-assessed tumour-free status—was achieved in 64% and 61% of cases at median follow-up periods of 546 and 247 days respectively. Critically, initial tumour volume emerged as a significant predictor of treatment success for both neoplasm types; small sarcoids (1 cm³) were six times more likely to achieve full clinical response than larger lesions (6 cm³), whilst perineal melanomas ≤0.3 cm³ showed an eleven-fold greater success rate than those ≥2.0 cm³, with location also influencing melanoma outcomes. With only five adverse events reported across the cohort, early intervention on small lesions offers clinicians a minimally invasive option, though practitioners should anticipate the local tissue response characteristic of TT's oncosis mechanism and understand that larger or anatomically challenging tumours
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Practical Takeaways
- •Intralesional tigilanol tiglate offers a viable non-surgical treatment option for equine sarcoids and cutaneous melanomas, with response rates around 60-74%
- •Earlier intervention when tumors are small significantly improves treatment success—consider this option before lesions become large or multiple
- •Treatment outcomes vary by tumor location and volume; perineal melanomas and smaller initial tumors show the best prognosis, informing client counseling about realistic expectations
Key Findings
- •73% of sarcoids and 74% of melanomas showed complete tumor volume regression following intralesional tigilanol tiglate treatment
- •Full clinical response (complete regression plus likely tumor-free status) achieved in 64% of sarcoids and 61% of melanomas at median follow-up of 546 and 247 days respectively
- •Treatment efficacy was significantly dependent on initial tumor volume, with 6-fold greater probability of response for small sarcoids (1 cm³) versus larger tumors (6 cm³)
- •Tumor location affected melanoma treatment response (p=0.005), with perineal melanomas showing 11-fold greater response probability for smaller volumes (≤0.3 cm³ vs ≥2.0 cm³)
- •Only 5 adverse events reported across 138 treated tumors, indicating good safety profile