Introduction

Splenic hemangiosarcoma (HSA) is an aggressive, highly metastatic tumor of vascular endothelium which carries a grave prognosis with surgery and standard of care (SOC) Doxorubicin (DOX). This is an expansion of a previous phase I study, which showed evidence of prolonged survival. We hypothesized that IMY alone and in combination with DOX may prolong survival.

Methods

This was a prospective, randomized double blind, placebo and SOC controlled trial. Dogs were eligible if they underwent splenectomy with a life expectancy ≥4 weeks. Owners opted for IMY alone or SOC DOX therapy (open label). Dogs receiving DOX were then randomized to the addition of IMY or placebo (blinded). All were monitored weekly for 15 weeks, then monthly until death.

Results

101 dogs were included in the final analysis, 25 DOX, 51 IMY, and 25 in the IMY with DOX groups. An interaction between treatment group and sex revealed that for males, there was no significant difference in Hazard Ratios (HR) amongst groups. Females receiving DOX alone had significantly lower HR compared to those receiving IMY alone (HR 0.21; p=0.004). Dogs with HCT ≤30 (HR5.28; p<0.001) at screening and stage III dogs (HR 2.9; p=0.014) had significantly higher HRs when controlling for sex and treatment group. Overall, IMY was well tolerated alone and in combination with Doxorubicin.

Conclusion

When controlling for HCT and stage, female dogs treated with IMY alone had reduced survivals compared to DOX treatment groups; in males there was no significant difference identified between SOC vs IMY based treatments.

Funding Information

This study was funded by the makers of I’m Yunity®.