A New Trial is Enrolling Dogs with Hemangiosarcoma

Hemangiosarcoma (HSA) is an aggressive cancer of the blood vessels and, sadly, one of the most common cancers diagnosed in dogs. In golden retrievers, for instance, hemangiosarcoma is the single most common type of cancer. 

With today’s conventional treatment (including surgery followed by Doxorubicin chemotherapy) outcomes are poor. Fewer than 20% of dogs survive beyond 9 months after diagnosis. New treatment options are desperately needed.

Paclitaxel is one of the most effective anticancer chemotherapy agents used in human cancer treatment today.  Paclitaxel interferes with microtubule function during cell division and can arrest cell division.  

Paclitaxel also has an anti-angiogenic effect, i.e., blocking the growth of new blood vessels that tumors need to grow.  Human patients with angiosarcoma, which is equivalent to canine hemangiosarcoma, are usually treated with paclitaxel.  

What’s Paccal Vet?

Although paclitaxel is a powerful chemotherapy drug widely used to treat various solid tumors in human patients, it has not been used to help dogs due to the high risk of severe allergic reactions and toxicities associated with the solvent used in its standard formulation, Taxol. 

Paccal Vet is a new formulation of paclitaxel that encapsulates the drug in nanosized particles, allowing for safer delivery without the harmful solvent. This approach improves tolerability in canine patients while maintaining the drug’s anti-cancer activity. 

Previous studies with Paccal Vet have demonstrated a safety profile that is generally similar to other chemotherapy drugs used in veterinary oncology. Its anti-tumor activity in selected cancers in dogs (including mast cell tumors, squamous cell carcinoma, and mammary cancer) has also been reported for Paccal Vet. These findings suggest that Paccal Vet may be a promising treatment option for dogs with hemangiosarcoma. 

What are the potential benefits and advantages of being part of the clinical trial?

A significant advantage is that the study is fully funded, covering costs for treatment, staging, imaging, blood work, and adverse events, making it a no-cost option for enrolled families.

Unlike Doxorubicin, Paccal Vet does not carry the same risks of cardiotoxicity or cumulative dose limitations. While formal efficacy results have not yet been published, Paccal Vet may offer the potential for a longer disease-free period.

Dogs enrolled in the trial will also benefit from regular medical check-ups and close monitoring throughout the study, including follow-up visits and diagnostic evaluations.

By participating, families are also contributing to critical research aimed at improving outcomes for canine hemangiosarcoma.

What are the potential risks?

Side effects may include fatigue, nausea, low white blood cell count, or, more rarely, liver issues or skin irritation.  Families need to take precautions when handling their dog’s waste (urine, feces, vomit, saliva) in the days following treatment to avoid exposure to the drug.

How is the study structured?

The trial consists of three phases: screening, treatment, and follow-up care. Dogs will receive Paccal Vet once every three weeks for a total of four doses. Each dog will have approximately 10–12 clinic visits over one year—including regular check-ups, blood tests, scans, and quality-of-life surveys—to closely monitor safety and efficacy. 

Where can my dog get this treatment?

• Veterinary Referral Center of Central Oregon – Bend, Oregon

• Bridge Animal Referral Center (BARC) – Edmonds, Washington

• VCA Northwest Veterinary Specialists – Clackamas, Oregon

• Pacific Northwest Pet ER and Specialty Center – Portland, Oregon

• BluePearl Pet Hospital, Tacoma – Tacoma, Washington

• Seattle Veterinary Specialists, BluePearl Kirkland – Kirkland, Washington

• Veterinary Specialty Hospital, North County – San Marcos, California

• Colorado Animal Specialty and Emergency (CASE) – Boulder, Colorado

What type of hemangiosarcoma? Is surgery required?

Dogs who qualify must have recently undergone splenectomy with confirmed splenic hemangiosarcoma. 

Who is sponsoring the study?

Paccal Vet was developed by Vivesto, a Swedish biotech company known for blood cancer and veterinary oncology drug programs.

Where can I get more information?

🔗 View the AVMA Registry for the Clinical Trial Listing (VCT24005788)

🔗 Visit CASTR Alliance for More Info

Who can I contact for the details?  

• Study Contact Name: Doctor Jim Perry

• Study Contact Email: jperry@castr-alliance.com

• Study Contact Phone: +15412096960

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Check out other articles and videos

• New Treatments for Hemangiosarcoma

• Curing Hemangiosarcoma: New Calviri Vaccine Study for Canine Patients

• Canine Cancer Causes and Prevention

• Surprising Findings from 2024

Questions? Email us at info@ccralliance, and we'll get back to you as soon as we can!

Canine Cancer Alliance is a non-profit organization supporting research for canine cancer cures.

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All information on the Canine Cancer Alliance website is for educational purposes only. It is not intended to be a substitute for professional veterinary advice.

Always seek guidance from your veterinarian with any questions regarding your pet’s health and medical condition.