A recent clinical study found that adding a novel vaccine to standard chemotherapy markedly improved long-term survival rates without adding substantial toxicity, offering new hope for managing this aggressive disease.
The study evaluated a new therapeutic approach combining standard DOX chemotherapy with an innovative conjugate vaccine technology called “immune Boost” (iBoost). This vaccine targets extracellular vimentin (eVim), a protein present on the surface of tumor blood vessel cells that is associated with cancer growth and spread.
The trial involved 23 client-owned dogs with visceral HSA. Following splenectomy, the dogs received six cycles of DOX alongside four doses of the eVim iBoost vaccine, followed by maintenance vaccinations. The outcomes for this group were compared to a historical control group of dogs that received only surgery and DOX.
Key findings from the study revealed a dramatic improvement in long-term survival. While the median overall survival time increased from 136 days to 235 days, the most significant benefits were seen in the one-year survival mark. The one-year survival rate for dogs receiving the combination therapy was 44%, compared to just 14% in the control group. The statistical analysis also showed a significant increase of 81 days in the restricted mean survival time at one year.
The combination of DOX and the eVim vaccine was reported to be well-tolerated. Adverse events were generally mild, limited to minor reactions at the injection site, and no systemic toxicity related to the vaccine was observed. The study also found that the chemotherapy did not interfere with the dog’s ability to mount an effective antibody response to the vaccine.
The study had limitations, including its open-label design and the use of a historical control group for comparison. The researchers noted that the full survival benefit might be even greater if all dogs received the combination therapy simultaneously. Importantly, the addition of propranolol, a drug sometimes used for its potential anti-cancer effects, did not appear to provide any additional benefit to the vaccine and chemotherapy regimen.
The results support the further clinical development of eVim-targeted vaccines, not only for veterinary medicine but also as a potential novel therapy for human patients facing angiosarcoma. Future studies with larger, prospective cohorts are planned to validate these encouraging results.
