CSU Animal Cancer Center Clinical Trial

Patient Disease:
We greatly appreciate your interest and involvement in this clinical trial evaluating a new form of cancer treatment for dogs, using a drug known as liposomal clodronate.  Your pet’s oncology clinician will explain the disease characteristics of malignant histiocytosis (MH) in dogs, as well as any other available treatment options for this tumor.  This handout will provide you with information on the purpose of this clinical trial, which is designed to investigate a new treatment for MH.  The brochure will also help explain your responsibilities and what procedures your pet may undergo if you choose to have your pet participate in the study.

Study Name:
Liposomal clodronate in canine cancer.

Purpose of the Study:
Macrophages are immune cells that normally scavenge bacteria and clear a variety of substances (such as cell debris, bacteria, and foreign materials) from the body.  Recent studies suggest that this cell type may actually play an important role in promoting tumor growth and spread (metastasis).  Therefore, we are investigating the effectiveness of a new compound that is designed to eliminate macrophages transiently from the body.  Canine MH is thought to be a tumor arising from macrophages and we have found that canine MH cells are susceptible to liposomal clodronate in vitro (see below).  Studies in mice have indicated that treatment with this drug can significantly inhibit tumor growth.  The study will investigate the effectiveness of a bisphosphonate cancer drug known as clodronate, which is being administered after being encapsulated within liposomes, which are tiny, spherical particles of lipids that are used to deliver various drugs in the body.  Bisphosphonates are used in the treatment of osteoporosis in people and in bone cancer in people and dogs.  Previous research found that liposomal clodronate was an effective agent for depletion of macrophages.  Malignant histiocytosis in dogs is thought to arise from malignant macrophages and our laboratory studies have shown that liposomal clodronate is very effective in killing of canine MH cells in vitro.  Therefore, we believe that administration of liposomal clodronate may also effectively eliminate MH cells in our canine patients in vivo.  The goals of this study are to determine whether repeated treatment with liposomal clodronate is both safe and effective as a cancer therapy for dogs with malignant histiocytosis (MH).

Patient Entry Criteria:
Dogs with biopsy confirmed MH tumor of any site are eligible for this study.  Prior treatment with conventional chemotherapy for MH is acceptable, though to be eligible for the study, the dog can no longer be receiving any form of chemotherapy.  Concurrent administration of other drugs such as NSAIDs that your dog was already receiving before the tumor was diagnosed will however be acceptable.  Dogs with any serious underlying diseases, including renal disease, liver disease, autoimmune disease, and chronic infectious diseases, are however excluded from the study.  Owners must consent to a postmortem examination (autopsy) at the time their pet dies or is euthanized.

Owner Responsibilities:
You are financially responsible for charges associated with staging tests to determine your pet’s eligibility for enrollment in this study. You are expected to make and keep all appointments according to the study protocol.  You must be committed to completing the entire protocol and follow-up examinations.  Please do not hesitate to obtain additional information from your pet’s oncology clinician if you do not understand something about the study or your pet’s care and treatment.

Financial Incentives:
Once enrolled, the study will pay for the costs of study-related blood work and biopsies and the cost of the liposomal clodronate.

Please contact our Consultation Coordinator at (970) 297-4195 if you are interested in learning more about clinical trials.