# Pharmacokinetics of bleomycin in dogs treated with electrochemotherapy

## TL;DR

This study examines how bleomycin behaves in dogs during electrochemotherapy, finding consistent drug levels that support current treatment protocols.

## Contribution

The study provides new pharmacokinetic data for bleomycin in dogs undergoing electrochemotherapy, supporting existing treatment timing and dosage guidelines.

## Key findings

- Bleomycin's half-life in dogs was 22.03 minutes, with no significant differences in tumour concentrations at different time points.
- The volume of distribution and clearance values suggest no need for dose adjustments based on body weight or age.
- The results validate the 8–28-minute window for applying electric pulses after drug administration.

## Abstract

Bleomycin (BLM) is a cytotoxic antibiotic used in veterinary oncology, primarily in electrochemotherapy (ECT), a local ablative therapy where electric pulses increase drug uptake in tumours. BLM is administered intravenously or intratumourally, with the standard intravenous dose for dogs being 15,000 IU/m², followed by electric pulses 8–10 minutes later. This protocol is derived from human oncology and lacks extensive pharmacological data in dogs. We studied BLM pharmacokinetics in 29 dogs with various tumours treated with intravenous BLM and ECT between 2017 and 2023. Samples were collected from serum of 15 dogs, serum and tumours of 8 dogs, and tumours of 6 dogs. The mean volume of distribution (Vd) of BLM was 224.5 ± 75.02 ml/kg, clearance (CL) was 7.04 ± 2.05 ml/kg/min, and area under the curve (AUC) was 65.87 ± 2.11 µg·min/l. The half-life (t₁/₂) of BLM in dogs was 22.03 ± 0.88 minutes. No significant difference was found in tumour BLM concentrations between 8 minutes post-administration and 2 minutes after pulse completion. These results support the recommended 8–28-minute window for applying electric pulses following intravenous BLM administration and may indicate no need for dose adjustments based on body weight or age.