New therapies, diagnostics mark advancements in veterinary oncology

Sue Ettinger, DVM, DACVIM (Oncology), delivering her lecture on veterinary oncology during the 2021 ACVC.

Veterinary oncology continues to evolve with new therapies and diagnostics indicative of the recent innovation associated with animal cancer care.

In a keynote address to kick off the Atlantic Coast Veterinary Conference (ACVC) in Atlantic City today, Sue Ettinger, DVM, DACVIM (Oncology)—well known as Dr Sue Cancer Vet—provided a review of recent advancements in diagnostics and treatments for cancer in companion animals.¹

Therapies

The session, “What’s new in cancer 2021,” first highlighted drug therapies that have recently received support from the FDA. These therapies include the following:

Tigilanol tiglate (Stelfonta: Virbac)

A high efficacy, fast-acting single injection, this therapy is indicated for mast cell tumor treatment in dogs. It works to induce tumor cell death quickly by directly destroying its blood supply, causing necrosis.

“It’s not chemotherapy,” said Ettinger. “It’s going to cause the tumor cell to be destroyed and fall off.”

Investigators have found that 75% of mast cell tumors treated with tigilanol tiglate needed only a single treatment to achieve resolution by 28 days, and 93% of the dogs studied had no recurrence by 84 days.² Additionally, the drug promotes healing at the wound site and provides a good cosmetic outcome, according to Ettinger.

“If they don’t have a complete response with 1 treatment, they can be retreated,” she said.

In another study cited by Ettinger, about 99% of patients treated with the drug demonstrated full healing within 3 months of injection, and most wounds were entirely re-epithelialized within 28 to 42 days of treatment.¹

According to Ettinger, tigilanol tiglate is generally well-tolerated. Studies have also shown that dogs remained free of disease at the injection site 12 weeks after a single dose in 96% of cases.¹

In administering the drug, the tumor should be measured by length x width x height x ½.

The dose is administered by insertion of a sterile, Luer-lock syringe with a 23-gauge needle to the tumor mass through a single injection site. The inserted needle can be fanned in a back-and-forth motion for distributing the therapy, according to Ettinger.

Verdinexor (Laverdia-CA1; Anivive Lifesciences Inc.)

An oral, antineoplastic therapy, verdinexor is conditionally approved by the FDA for lymphoma treatment in dogs. According to Anivive, it is the first small-molecule selective inhibitor of nuclear export drug specifically created for canines.

Verdinexor is used to control the growth and inhibit the spread of cancer in dogs by preventing certain proteins from leaving the nucleus of cancerous cells.

In a study cited by Ettinger, verdinexor demonstrated sustained benefit for many canine patients with lymphoma, including 17 of 58 dogs that showed no disease progression for at least 56 days after taking the drug. Another 3 dogs showed no disease progression for at least 182 days after taking verdinexor.¹

According to Ettinger, verdinexor was well-tolerated in clinical studies with grade 1-2 anorexia reported as the most common adverse effect.¹

Prescribed by veterinarians, verdinexor is administered twice per week and can be administered at home.

Rabacfosadine (Tanovea CA-1; VetDC Inc.)

Fully approved by the FDA in July 2021, rabacfosadine injection is also indicated for lymphoma treatment in dogs. According to the FDA, this drug was the first conditionally approved new animal drug for dogs to receive the agency’s full approval.³

“This is an ‘every 3 weeks’ option,” said Ettinger.

According to the FDA, the efficacy of rabacfosadine was demonstrated in a clinical study with 158 dogs that had been diagnosed with multicentric lymphoma and with at least 1 enlarged peripheral lymph node. The study demonstrated that rabacfosadine extended the median survival rate of the studied dogs by 61 days. Dogs that showed a complete response to the medication had a median progression-free survival extension of 168 days.³

Ettinger said the majority of adverse effects shown with rabacfosadine, reflected in multiple studies, are similar to those of most chemotherapy drugs. However, additional adverse effects with rabacfosadine included pulmonary fibrosis, dermatopathy, and anorexia. Overall, though, she said the drug is well-tolerated.

Rabacfosadine is administered intravenously at 1mg/kg every 3 weeks.

Diagnostics

Along with drug therapies, Ettinger spoke about new liquid biopsies for detecting cancer in dogs. Highlights included the NuQ Vet Cancer Screening Test by Volition. A blood test, the screening tool requires a 4-hour fast and is proving useful for discovering lymphomas and hemangiosarcoma. These are some of the most common forms of canine cancer, Ettinger said.

“I always get the question about cats. They are working on a cat assay as well,” said Ettinger.

According to Ettinger, 80% of clients decline lymphoma treatment for their dogs. “Two thousand dogs every day are being diagnosed with lymphoma,” she said.

Ettinger encouraged the ACVC audience to stay educated on veterinary oncology options. Inspired by pet parents seeking good information, she started an educational blog and uses social media to share information. Her digital persona as “Dr Sue Cancer Vet” also includes a series of vlogs, including those that demonstrate using some of the treatment options she outlined during the keynote address.

References

1. Ettinger S. What’s new in cancer 2021. Presented at: Atlantic Coast Veterinary Conference; Atlantic City, New Jersey. October 11-13, 2021.
2. Randomized controlled clinical study evaluating the efficacy and safety of intratumoral treatment of canine mast cell tumors with tigilanol tiglate. J Vet Intern Med. 2021;35(1):415-429. doi:10.1111/jvim.15806.
3. FDA grants first full approval for treatment of lymphoma in dogs. News release. FDA. July 15, 2021. Accessed October 11, 2021. https://www.fda.gov/news-events/press-announcements/fda-grants-first-full-approval-treatment-lymphoma-dogs