Clinical Studies

Novel therapy for canine brain tumors

"A study of the safety and effectiveness of Toca 511, a replication competent murine leukemia virus with a cytosine deaminase gene, administered transcranially to companion dogs with spontaneous brain tumors and followed by oral treatment with 5 fluorocytosin"


Purpose of Study

The purpose of this study is to evaluate the safety and effectiveness of combining gene therapy with 5-FC (an anti-fungal drug) to treat primary brain tumors in dogs. This treatment has shown promise in mouse brain tumors and is currently in clinical trials in humans with brain tumors. An effective standard treatment for canine brain tumors has not been established in veterinary medicine. Current possible therapies include surgical removal, radiation therapy and chemotherapy, but canine responses to these therapies have been poorly documented and survival times have been unclear. Using gene therapy to treat brain tumors can be beneficial because only the tumor, and not the entire body, would receive the cancer treatment; therefore, eliminating any systemic side effects associated with treatment.


This form of viral gene therapy may be effective in controlling the growth of canine brain tumors and may result in a longer survival time. The study will cover the costs of the brain biopsy procedure, viral infusions, brain tumor removal surgery if indicated, 5-FC, routine intensive care unit monitoring, blood work and MRI scans (approximate value: $10,000).

Enrollment Requirements

Dogs enrolled in this study must have a diagnosis of a brain tumor. They need to be deemed healthy enough, by a neurologist, to undergo anesthesia, a brain biopsy procedure, brain surgery to remove the tumor, viral infusions and MRI scans. Following the viral infusion, dogs will be required to remain at WSU-VTH for at least five days. Two to six weeks after viral infusion, each dog will either begin taking the oral drug 5-FC or will undergo surgery to remove the tumor and then begin taking 5-FC. Every four weeks, owners will need to give the oral drug to their dogs for five days. For six months following the start of 5-FC, dogs will need to return to WSU-VTH every eight weeks for a neurologic exam, blood work and an MRI. If in the unfortunate event that the dog dies during the study period, an autopsy is required to confirm the cause of death.

Treatment Methods

Participating dogs will be anesthetized for the biopsy procedure and viral infusion of the brain tumor. Immediately following these procedures, the dog will receive an MRI scan. Once the scan is completed, the dog will remain hospitalized at WSU-VTH for at least five days for routine neurologic monitoring. Two to six weeks after the viral infusion, the dog will return to WSU-VTH to either begin taking a drug called 5-FC or undergo surgical removal of the brain tumor and then begin taking 5-FC. For the next six months, participating dogs will need to return to WSU-VTH every eight weeks for a neurologic exam, blood work and an MRI.

Owner Responsibilities

Owners are responsible for the costs of additional hospitalization, medications and procedures associated with unforeseen complications. In addition, to remain in the study, owners are required to bring their dogs back to WSU-VTH two to six weeks after viral infusion and then every eight weeks for the following six months.

Contact Information

For more information please contact:

Valorie Wiss, Clinical Studies Coordinator
Office: 509-335-0798
Cell: 509-432-5345

Dr. Annie Chen-Allen
Office: 509-335-0711