T Cell Experience Programs for Canine Lymphoma

WHAT IS LYMPHOMA?

Lymphoma (LSA) is one of the most common cancers in dogs. It is a cancer of lymphocytes which are cells of the immune system. LSA comes in several forms, including: gastrointestinal, mediastinal (chest), multicentric (involving many lymph nodes) and extranodal (involving organs such as the eyes, brain, kidney, skin, etc). Most dogs are diagnosed with the multicentric form (80-85%). The “typical” canine lymphoma patient is a middle-aged dog presented to the veterinarian because one or more lumps have been found. Usually the dog has not been showing any signs of illness and the lymph nodes are not painful to the dog.

Diagnosis is based upon either cytology or biopsy of a lymph node or affected organ. A workup for LSA involves the following: CBC and serum chemistry to evaluate all body systems; Chest radiograph (x-ray) to look for evidence of spread to the chest cavity or lungs; Aspirates of the lymph nodes to determine the phenotype (T cell or B cell), and in some cases an abdominal ultrasound to evaluate the spleen, liver and abdominal lymph nodes for evidence of the cancer.

We generally break LSA in three groups, B cell (~2/3 of the dogs), T cell (~1/3) and null cell (<2%). This information may be obtained through either biopsy or more novel techniques that are less invasive such as immunocytochemistry (ICC), flow cytometry, or PCR for antigen receptor gene rearrangement (PARR). Phenotyping of LSA is important as the result plays a role in prognosis (as B cells carry a better prognosis) and in therapy (as we treat B and T cell LSA with different protocols).

For many years, the “standard of care” treatment for most canine lymphomas has been doxorubicin-based combination chemotherapy, often referred to as CHOP chemotherapy. The acronym “CHOP” denotes the four drugs thought to have the greatest activity against lymphomas: Cyclophosphamide, Hydroxydaunorubicin (doxorubicin), Vincristine, Cyclophosphamide. Oncologists are now modifying protocols depending upon whether the patient has a B cell or T cell lymphoma, thus each are treated differently at Hope VS.

WHAT ARE MONOCLONAL ANTIBODIES?

In human oncology, lymphoma is treated with a combination of chemotherapy, such as CHOP, and monoclonal antibodies.  A monoclonal antibody (mAb) can be used to specifically bind to target cells or proteins. This may then stimulate the patient’s immune system to attack those targeted cells and remove them from the body. Normal lymphocytes can be replenished, as stem cells within the bone marrow are not targeted and as such normal cells are replenished but the cancer lymphocytes are not. These have now become standard of care therapy in human oncology.

In veterinary medicine, we now have a B cell and T cell monoclonal antibodies for use in our patients. The monoclonal antibodies are produced by Aratana Therapeutics. The B cell monoclonal antibody has gained full approval by the USDA and the T cell monoclonal conditional approval.

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HOW CAN MY DOG RECEIVE THE MONOCLONAL ANTIBODY?

  • THROUGH AN EXPERIENCE PROGRAM: We are partnering with Aratana therapeutics on a T cell experience program in which patients with T cell lymphoma can receive the monoclonal antibody. This is NOT a clinical trial.
    • T cell experience program-Patients with T cell lymphoma can receive any chemotherapy protocol with the monoclonal (no restrictions) once deemed they are not eligible for T Cell trial. The owner is responsible for costs associated with the monoclonal and its administration.

This is a very exciting time in veterinary oncology and Hope VS is excited to be on the forefront and provide monoclonal antibodies to patients in our region.

WHO DO I CONTACT FOR ELIGIBILITY?

Primary Contacts at HopeVS: Dr. Craig Clifford and Dr. Kate Vickery

Phone: (610) 296-2099

Email: [email protected]

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