Introduction

Hemangiosarcoma (HSA) of the canine spleen is an aggressive, chemotherapy resistant tumor, and despite surgery and chemotherapy, most patients succumb to their disease within 6 months. New treatment modalities, such as immunotherapy, may offer a therapeutic advantage. Immunocidin is a USDA-licensed, mycobacterial cell wall fraction, non-specific immunotherapeutic with preliminary intravenous (IV) safety data in dogs with various cancers. The study aims were to evaluate safety of combination doxorubicin and Immunocidin, and the impact of Immunocidin on overall survival time (OST).

Methods

Patients with histologically diagnosed splenic HSA were prospectively enrolled to receive 5 doses of IV doxorubicin (30 mg/m²) and IV Immunocidin every 2 weeks. Adverse events (AEs) were graded according to the VCOG CTCAE scheme. OST was calculated from the date of diagnosis to date of death or loss to follow-up.

Results

Eighteen (18) dogs were enrolled (March 2019 to November 2020). At presentation, 2/18 had confirmed hepatic metastasis. AEs during administration of Immunocidin were infrequent and included hypertension, fever, hypersensitivity, and lethargy. One patient also experienced limb and facial twitching and was removed from the study. The most common AEs following treatment included lethargy, hyporexia, and diarrhea. One patient developed VCOG grade V diarrhea, thrombocytopenia, and anemia (cause uncertain). Doxorubicin dosing was reduced to 27 mg/m² due to observed gastrointestinal AEs. The median OST was 147 days (range: 39–668 days).

Conclusion

The combination of doxorubicin and Immunocidin appeared to cause more gastrointestinal effects than is expected with doxorubicin alone. No improvement in OST was noted in this small group of dogs.

Funding Information

This study was generously funded by NovaVive.