# Clinical impact of butterbur shoot extract in dogs with oral melanoma: a combined phase 1 and 2 clinical trial

## TL;DR

A clinical trial in dogs with oral melanoma found that a butterbur shoot extract is safe and may improve survival rates.

## Contribution

This study demonstrates the safety and potential clinical benefit of butterbur shoot extract in treating canine oral melanoma.

## Key findings

- BSE at 200 mg/kg was found to be safe with no dose-limiting toxicities.
- BSE administration significantly extended overall survival in dogs with stage 3 oral melanoma.
- Grade 1 alanine aminotransferase elevation and diarrhea were the most common adverse effects.

## Abstract

Oral melanoma is one of the most devastating cancers in dogs. We previously developed a novel agent extracted from Japanese butterbur shoots and its petasin derivatives demonstrated anti-proliferative activity in canine oral melanoma cells. The aim of this study was to evaluate the safety and clinical efficacy of the butterbur shoot extract (BSE) in dogs with oral melanoma as a combined phase 1 and 2 study.

All enrolled dogs underwent radiation therapy or surgery as local therapy before BSE administration. We enrolled nine dogs in the phase 1 study, and BSE was orally administered at doses escalating from 50 to 200 mg/kg. Grade 1 alanine aminotransferase elevation and diarrhoea were observed in each dog. We determined that 200 mg/kg BSE was safe to administer. We subsequently administered it to sixteen dogs with stage 3 oral melanoma in the phase 2 study. Their progression-free survival and overall survival were compared with those of the historical controls, and adverse events were assessed. BSE administration significantly extended overall survival but did not prolong progression-free survival. No dose-limiting toxicities were observed.

These results indicate that 200 mg/kg of BSE is safe to administer and may improve the outcome of canine oral melanoma.

The online version contains supplementary material available at 10.1186/s12917-026-05326-w.