Immunotherapy clinical trials to treat HSA:
https://www.vet.upenn.edu/research/centers-initiatives/mason-immunotherapy-research/therapies-trials/canine-hemangiosarcoma
Canine Hemangiosarcoma
Contact info is on the link above if interested in reading more or contacting him.

Dr. Mason’s lab is currently recruiting dogs for a novel clinical trial using immunotherapy to treat canine hemangiosarcoma.
Hemangiosarcoma is a common, aggressive cancer that arises from the cells that line blood vessels. Common sites of occurrence include the spleen, liver, and the right side of the heart.
The current standard of care for hemangiosarcoma that occurs in the spleen is surgical removal of the spleen followed by chemotherapy. Unfortunately despite surgery and chemotherapy, the disease usually spreads and most dogs succumb to their disease within 6-12 months of diagnosis.