There are currently several effective treatments available for arthritis pain but there are many dogs that do not respond to these therapies, the effectiveness of these treatments can diminish over time, and some can have unacceptable side effects. If your dog has been diagnosed with moderate to severe arthritis pain in one or both knees (stifles) which you feel it is not adequately controlled with the use of standard pain management measures, he or she may be a candidate for a new study assessing the effectiveness of a new way to manage this pain. 
RTX or resiniferatoxin is a capsaicin-like medication that has been shown in previous studies to decrease activity along the chronic pain pathway thereby decreasing the sensation of chronic, aching pain. The goal of this study will be to measure the safety and effectiveness of a one-time injection of RTX into the synovial sac of the affected knee for a minimum of 21 days after injection.

Eligibility requirements include:

  • previous diagnosis of arthritis in one or both knee joints
  • evidence of arthritis in at least one knee joint confirmed by a PennVet radiologist
  • weight greater than 33 pounds
  • no significant neurologic or orthopedic conditions on physical exam
  • no signs of acute cruciate rupture within the 3 months prior to enrollment
  • cruciate repair, if performed, must be more than 6 months prior to enrollment

This is an open label study, meaning each dog enrolled will receive the RTX injection. Any screening radiographs (if needed), blood work and all follow-up will be included in the study at no cost to the owner. Throughout the course of the study, you will answer sets of questions asking about pain your dog may be experiencing, his or her ability to get around, as well as his or her quality of life. In addition to the questionnaires, we will be objectively measuring your dog’s ability to walk (gait analysis) by measuring how much force your dog exerts on his or her affected limb. Your dog will also wear an unobtrusive activity collar throughout the study, which monitors activity 24-hours a day. This study requires 5 visits to PennVet over a one month period of time.

If you are interested in learning more about this study, please contact the Veterinary Clinical Investigations Center at 215-573-0302 or vcic@vet.upenn.edu.