Clinical Studies

Cats Receiving Vincristine

“Enhancing the therapeutic index of vincristine in cats”


Purpose of Study

The purpose of this study is to determine if cats with a specific genetic characteristic (MDR1 mutation) are more likely to develop side effects from vincristine compared to cats without the specific genetic characteristic.


All MDR1 genotyping will be done at no cost to you. Your cat’s susceptibility to adverse drug reactions to vincristine and other drugs may be better predicted by knowing your cat’s MDR1 genotype. This has been shown to be the case in dogs.  In addition, you and your cat could be helping future cats with cancer: rather than using the current “trial and error” approach to chemotherapy drug dosing, the MDR1 genotype may be used to help predict safer dosing strategies for affected cats.

Enrollment Requirements

Participating cats must receiving vincristine, or scheduled to receive vincristine, as routine treatment for their cancer diagnosis. No change in the standard protocol schedule for vincristine is required to participate in this study. Cat owners must fill out (1) a consent form, (2) a form after treatment, and keep the standard protocol schedule for vincristine treatment, which requires blood work prior to and one week after vincristine administration.

Treatment Methods

Once you have enrolled your cat and have signed the study consent form, we will get a DNA sample; with either a check swab or a small, half-teaspoon sized, blood sample. Your cat will then receive their vincristine treatment as directed by your Oncologist. You will be asked to monitor your cat’s dietary and elimination habits closely for 7-10 days after treatment and record any abnormalities on a 1-page Adverse Event Report Form. 7-10 days after treatment, your cat will need to return to the veterinarian for a complete blood count. At this time, you will submit the Adverse Event Report Form and your participation in the study will be complete.

Owner Responsibilities

Owners are responsible for the costs of all treatments and diagnostic tests for your cat EXCEPT for the costs associated with MDR1 genotyping. In addition, this study asks owners to monitor their cats closely after vincristine administration, record any reaction their cats may have to the chemotherapy drug on the Adverse Events form, and submit that form to their veterinarian when they and their cat return for a routine complete blood count test (7-10 days after vincristine treatment).


Multiple veterinarians are participating in this study with Washington State University Veterinary Teaching Hospital. If you do not live near Pullman, Washington, your cat is scheduled to receive vincristine, and you would like to participate, please contact us. We would be happy to collaborate with your Oncologist if s/he is not yet part of the study.

Contact Information

For more information please contact:

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