Cancer Immunotherapy Developed for Humans Will Be Used to Treat Dogs

As the One Health initiative grows to bridge the gap between human and veterinary medicine, there has been significant research in the area of comparative oncology. So far this year, American Veterinarian^® has reported on immunotherapies that may slow growth or even shrink gliomas in dogs and humans, a liquid biopsy assessment tool to detect tumor cell mutation, and a shared study between the American Kennel Club Canine Health Foundation and the V Foundation for Cancer Research on the treatment of bladder cancer .

Now, another One Health study can be added to this auspicious list. The University of Alabama at Birmingham (UAB) is partnering with veterinary universities to conduct the first immunotherapy study for brain tumors in dogs using an oncolytic herpes simplex virus known as M032.

“Brain tumors in dogs and humans are remarkably similar,” said Renee Chambers, DVM, MD, a UAB neurosurgeon and professor in the department of neurosurgery at UAB School of Medicine. “They share similar rates of incidence and mortality, and they share similar symptoms such as seizures, which is often the first symptom observed in both humans and dogs. Treatment is very much the same too, with surgery, radiation, and chemotherapy the standard of care. It is not unreasonable to assume that the dog will be a highly useful model of human brain tumors.”

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M032 is a second-generation oncolytic herpes simplex virus that selectively replicates in tumor cells. The virus infects tumor cells while leaving healthy cells alone. M032 kills tumor cells directly through oncolytic replication and then proceeds to infect tumor cells in proximity, continuing the process of tumor destruction. M032 was developed by James Markert, MD, chair of the UAB Department of Neurosurgery, and is a second-generation virus to the genetically engineered virus known as G207, which was initially designed for clinical use in patients with malignant brain tumors.

“Both G207 and M032 have been engineered to minimize the production of any toxic effects for the patient receiving the therapy,” said Dr. Markert. “Both are now in human studies, an M032 study in adults at UAB, along with a companion pediatric study of G207 underway at Children’s of Alabama. These studies mark the first time one institution has conducted trials of genetically engineered herpes virus in both adult and pediatric—and now canine—populations.”

Dr. Chambers is working with Auburn University, University of Georgia and Mississippi State University to use M032 to treat their canine patients with naturally occurring brain tumors. The goal is to treat about 14 dogs per year.

“We anticipate that M032 will be as safe and effective in dogs as it is proving to be in humans,” Dr. Chambers said in an interview with UAB. “It opens up an exciting new research pathway while providing the potential of a therapy that could benefit both humans and canines with brain tumors.”

The first step of the project will be to determine an optimal and safe dose of the virus for canine patients. From there, Dr. Chambers said she and her academic veterinary partners will combine this therapy with a checkpoint inhibitor that is expected to keep the immune system “turned on” to capture and kill even more tumor cells.

“This work is important not only to canine brain tumor therapies but also to devising safer and more effective therapies for humans,” Dr. Chambers said. “It will critically inform the medical community on whether this combination approach, using an oncolytic virus followed by a checkpoint inhibitor, will be the next step in the successful treatment of brain tumors in both people and pets.”