A clinical trial is a study in dogs in which the safety and beneficial effects of a new cancer treatment are determined. Other clinical trials focus on new ways to detect cancer more effectively.
Clinical trials are different from laboratory animal studies in that the participating dogs are pet dogs that have naturally-occurring cancer, and the dogs are receiving a treatment that is expected to be as effective as or better than other drugs at treating the cancer.
Dogs participating in clinical trials live at home with their families and come into the Purdue University Veterinary Hospital periodically for evaluation and treatment.
Clinical trials are crucially important because this is the best way to learn how to detect and treat cancer more effectively. The benefits are expected to apply to the individual dog, to future dogs with cancer, and potentially to human cancer patients. Although much progress has been made in treating and preventing cancer, more progress is still needed!
The diagnosis of cancer is based on a tissue biopsy that is collected and analyzed to determine if the dog has cancer, and if so, what type of cancer. If the diagnosis of cancer is made, the dog owner can talk to their regular veterinarian and to a staff member or veterinarian in the Purdue Comparative Oncology Program (PCOP) to find out if their dog could be eligible for a clinical trial at Purdue University.
Additional tests may be needed to see if the dog could be enrolled in a trial, and to confirm that the clinical trial is the best option for the individual dog. The dog owner has to provide informed consent for the dog to participate in the trial. Once the dog is enrolled in a clinical trial, he/she will be evaluated periodically at the Veterinary Hospital.
Depending on the specific trial, the treatments could involve oral medicines given by the pet owner at home, or medications administered at the Veterinary Hospital or by the primary care veterinarian in the dog’s home town. It is important to point out that clinical trials are much different from experimental laboratory animal research. The dogs live at home other than the periodic visits to the Veterinary Hospital. The treatments are selected and the trial designed with the goal to minimize risk of side effects and to maintain good quality of life for the dog. All clinical trials are approved by the Purdue Animal Care and Use Committee.
There are several benefits to enrolling your dog in a clinical trial at the Veterinary Hospital.
First, the trial may allow your dog to receive treatment with a new cancer therapy that is more effective than existing therapies, or it may help your dog after other therapies are no longer effective.
Second, by enrolling your dog in a clinical trial, you and your dog are making a contribution towards advancing our understanding of cancer. This will lead to better diagnostic tests and improved therapies for pet dogs with cancer and potentially people with cancer. Because certain types of cancer are extremely similar between dogs and humans, successful results in dog studies can ultimately lead to benefits for humans too.
An additional benefit for a dog participating in a clinical trial, is the treatment is often less expensive than other treatments. Depending on the level of funding, the trial may provide financial support that covers part or all of the cost of treating your pet’s cancer as long as the dog is in the clinical trial.
There are many advantages to a dog participating in a clinical trial. The main “unknown” is it has not yet been proven that the new treatment will be effective and safe as expected. For a given trial, the veterinarian will discuss with the dog owner what is currently known about the new treatment, why it is expected to be beneficial, and what the known risks are.
There may be, however, risks, i.e. side effects, that have not yet been seen, but which could occur. Dogs in a clinical trial will be monitored closely for any side effects, and the treatment adjusted or discontinued should it not be well tolerated. If the dog’s quality of life is not good on a given treatment, the veterinarian will discuss other treatment options with the dog owner. These other options could be part of a study or may be therapies available off study. In addition, a pet owner can withdraw their dog from a study at any time if they wish to do so.
To participate in a clinical trial at the Veterinary Hospital, the diagnosis of the cancer must be made by a tissue biopsy examined by a veterinary pathologist. There are many types of cancer and many non-cancerous conditions that can look similar to the naked eye, and even with examination of cells from a mass. Therefore a tissue biopsy is crucial to confirm the type of tumor present in order to select the best treatment and to confirm that the clinical trial would be potentially beneficial to the dog. A biopsy is required prior to enrollment of your pet in a cancer-related clinical trial at Purdue.
Most biopsies are performed with the dog under general anesthesia or heavy sedation. There are many methods for performing a biopsy, and the method used varies according to the location of the tumor in the dog’s body. For dogs with bladder cancer, a biopsy is often performed using a specialized instrument called a cystoscope. A cystoscope is a long, thin, tube-shaped instrument with a camera on the end of it, which is used to nonsurgically obtain biopsy samples from tumors inside the bladder and urethra. For dogs with lymphoma, a small surgical incision is made over one of the lymph nodes affected by the cancer and a small wedge-shaped piece of tissue is removed from the affected lymph node. Biopsy procedures are generally very well-tolerated by pets with cancer, and most pets experience minimal to no side effects or complications related to the procedure.
A necropsy in a dog is similar to an autopsy in a human. Briefly the body and tissues are examined after the dog has died. Tissue samples are removed and examined by the pathologists. Permission to perform a necropsy is requested when a dog in a clinical trial dies or is euthanized due to poor quality of life from the cancer or other conditions.
The information learned can be extremely useful in determining how well the treatment had worked, how and why the cancer was progressing (if it was growing), and if any adverse effects from therapy had occurred. In fact, the information from a necropsy is so important, that we often ask owners of dogs with bladder cancer and lymphoma to allow a necropsy even if the dog was not in a clinical trial.
The necropsy can be completed and then cremation performed, or the dog owner can take the dog’s body for burial. If a dog owner does not want a necropsy performed, due to any reason, then the procedure will not be done.
If you would like more information about a clinical trial, or if you have questions, please contact the following staff members concerning clinical trials at the Veterinary Hospital.