Background: Huachansu, a Chinese medicine that comes from dried toad venom from the skin glands of Bufo gargarizans or B. melanostictus, has been used in the treatment of various cancers in China. The authors conducted a pilot study, using a phase 1 trial design, of huachansu in patients with advanced cancer.
Methods: Huachansu was administered intravenously for 14 days followed by 7 days off (1 cycle). Without significant adverse events or progressive disease, treatment continued beyond 2 cycles. The dose of huachansu was escalated as follows with 3 patients per cohort: 10 (level 1), 20 (level 2), 40 (level 3), 60 (level 4), and 90 (level 5) mL/m(2).
Results: Fifteen patients (hepatocellular cancer, n = 11; nonsmall cell lung cancer, n = 2; pancreatic cancer, n = 2) were enrolled in the trial, and no dose-limiting toxicities (DLTs) were found. Eleven patients had no drug-related toxicity greater than grade 1. Six (40%) had stable disease (median duration, 6.0 months; range, 3.5-11.1 months). One of these patients (with hepatocellular cancer) had 20% regression (duration, 11 months) (dose level 1). Quality of life improved for patients with stable disease. Plasma bufalin concentration reached maximal levels at the end of the 2-hour infusion and was proportional to the amount of drug being administered (0.81-3.38 ng/mL).
Conclusions: No DLT was observed with the use of huachansu at doses up to 8x higher than typically used in China. Six patients had prolonged stable disease or minor tumor shrinkage.