When a beloved dog or cat is diagnosed with a severe, refractory, or terminal illness—most commonly an aggressive cancer like lymphoma, osteosarcoma, or hemangiosarcoma—the news is devastating. Standard treatment options, while established, can sometimes offer limited long-term survival or carry costs that place them out of reach. In these high-stakes moments, pet owners and referring veterinarians frequently turn to veterinary clinical trials as a potential pathway to access cutting-edge, experimental therapies before they are widely available on the market.

Veterinary clinical trials represent a crucial bridge between laboratory discoveries and everyday clinical practice. These studies evaluate the safety and efficacy of novel pharmaceuticals, immunotherapies, vaccines, and medical devices in client-owned companion animals. However, enrolling a pet in a trial is not a simple choice or a free alternative to standard veterinary care. It is a structured scientific and financial commitment that requires a clear understanding of eligibility criteria, study phases, randomisation risks, and the real division of costs between clinical trial grants and the pet owner.

This guide provides a comprehensive roadmap for navigating veterinary clinical trials in the United States. It outlines how these studies are designed, where to find them using canonical resources like the AVMA registry and the National Cancer Institute (NCI) Comparative Oncology Program, how to evaluate inclusion and exclusion criteria, and what the financial realities of enrollment look like.

Quick answer

To find a veterinary clinical trial, search the AVMA Veterinary Clinical Trials Registry (veterinaryclinicaltrials.org) and the NCI Comparative Oncology Program trial list by your pet's species and condition. Enrollment is through a participating university or specialty hospital, eligibility is strict, and while the investigational treatment and study-related care are often covered, trials are not always free and you may pay for standard care, diagnostics, and travel.

---

What is a veterinary clinical trial and what are the phases?

A veterinary clinical trial is a prospective research study conducted in client-owned animals to evaluate the safety, dosage, efficacy, and side effects of an investigational medical intervention. Unlike laboratory research, these studies are conducted in a real-world clinical setting, typically at veterinary teaching hospitals or private specialty clinics, under the supervision of board-certified specialists.

Just like human clinical trials, veterinary trials progress through distinct, sequential phases to ensure safety and gather rigorous scientific evidence:

• Phase I (Safety and Dosage): These initial studies involve a small cohort of pets (typically 10 to 20 patients). The primary goal is to determine the maximum tolerated dose (MTD) of a drug, identify acute toxicities, and evaluate how the drug is absorbed, distributed, and excreted (pharmacokinetics). These studies are often open to pets with various advanced cancers or conditions that have failed all standard therapies.
• Phase II (Efficacy and Safety): Once a safe dosage is established, Phase II trials enroll a slightly larger cohort (typically 20 to 50 patients) with a specific target disease (e.g., canine osteosarcoma or feline chronic kidney disease). The goal is to determine if the drug shows sufficient therapeutic activity (objective response rate) to warrant further testing, while continuing to monitor for side effects.
• Phase III (Comparative Efficacy): These trials involve large groups of patients (often 100 or more) and compare the investigational treatment against the current standard therapy or a placebo. Phase III trials are designed to prove that the new treatment is either superior or non-inferior to standard options, and they represent the final step before seeking regulatory approval from agencies such as the FDA Center for Veterinary Medicine (CVM) or the USDA Center for Veterinary Biologics (CVB).
• Phase IV (Post-Market Surveillance): Conducted after a drug has received regulatory approval and is commercially available, Phase IV studies monitor long-term safety, detect rare side effects, and evaluate real-world efficacy across thousands of patients.

To clarify the difference between an investigational trial and a licensed therapeutic, consider the Oncept canine melanoma vaccine. Oncept is a fully USDA-licensed biologic that primary care veterinarians and veterinary oncologists prescribe and administer routinely. Conversely, patients in a clinical trial are receiving unlicensed, experimental agents—such as novel tyrosine kinase inhibitors, CAR-T cell immunotherapies, or investigational viral vectors—that can only be accessed through participation in an approved study protocol.

How do I find a clinical trial for my dog or cat?

Finding an active clinical trial requires searching multiple regional and national databases, as there is no single, all-encompassing global registry. The primary resources for locating open studies in North America include:

1. The AVMA Veterinary Clinical Trials Registry (AVMA VCTR)

Formerly known as the Animal Health Studies Database, the AVMA Veterinary Clinical Trials Registry (accessible at veterinaryclinicaltrials.org) is the central search tool managed by the American Veterinary Medical Association. It connects pet owners and veterinary professionals with clinical trials across the United States and Canada. Users can filter searches by:

• Species: Canine, feline, equine, bovine, and avian.
• Disease/Condition: Oncology, neurology, cardiology, dermatology, and internal medicine.
• Location: Searching by state or specific academic institution.

The VCTR is actively updated, and the AVMA regularly publishes bulletins highlighting new registry listings (such as the AVMA VCTR April 2026 update), providing a reliable signal of which studies are actively recruiting.

2. The NCI Comparative Oncology Program (COP)

The National Cancer Institute’s Comparative Oncology Program operates the Comparative Oncology Trials Consortium (COTC). The COTC designs and runs clinical trials for dogs with naturally occurring cancers across a network of roughly 20 academic veterinary schools in the US. These trials are highly structured, federally funded, and specifically focused on therapies that have translational relevance—meaning the data gathered from treating pet dogs helps inform human oncology trials. Open trials can be searched directly at ccr.cancer.gov/comparative-oncology-program/trials.

3. Academic Veterinary Teaching Hospitals

Most veterinary schools run independent, locally funded clinical trials alongside national consortium studies. Major academic programs manage a significant volume of trials annually. For example, Colorado State University’s Flint Animal Cancer Center (csuanimalcancercenter.org) manages an average of about 30 active oncology trials per year, covering conditions like osteosarcoma, lymphoma, soft-tissue sarcoma, and brain tumors. Other leading programs with dedicated trial lists include:

• Penn Vet (University of Pennsylvania): Renowned for comparative immunotherapy trials, including CAR-T cell therapy and investigational treatments for canine urothelial (bladder) carcinoma.
• North Carolina State University (NC State): Active in trials investigating osteosarcoma, lymphoma, hepatic tumors, and novel pain management strategies.
• Cornell University: Focuses on endocrine, cardiac, and oncological studies.
• The Ohio State University (OSU): Prominent partner in the COTC network with a broad range of veterinary clinical trials.

4. Secondary Registries

While ClinicalTrials.gov is the gold standard database for human clinical trials, it does contain a small number of veterinary studies, particularly those investigating zoonotic diseases or translational comparative medicine. However, it is poorly suited as a primary search tool for veterinary trials: the database has no structured "species" field, so a text search for terms like "canine" or "bovine" is heavily contaminated by human medical trials (such as "canine retraction" in orthodontic studies, "bovine" bone grafts in dental implants, or "equine-assisted therapy" in human psychotherapy). For this reason, owners and veterinarians should rely on the dedicated AVMA VCTR and NCI COP portals as their primary search tools, and treat ClinicalTrials.gov only as a secondary check.

Registry / Portal	Primary Focus	Best Used For
AVMA VCTR	All veterinary medical conditions	Broad searches across species, geography, and specialties
NCI COTC Trials	Comparative oncology (translational cancer research)	Accessing cutting-edge cancer immunotherapies at academic centers
Academic Teaching Hospitals	Local university-sponsored trials	Finding trials near your home with specific local coordinators
Veterinary Cancer Society (VCS)	Oncology resources and referral networks	General education and trial landscape overviews

Am I eligible to enroll my pet, and what are the inclusion criteria?

Enrolling a pet in a clinical trial is not guaranteed, even if a study is recruiting for your pet's specific diagnosis. Clinical trials are scientific experiments that require a highly uniform patient population to ensure that the data collected is valid. Consequently, every trial has a strict set of inclusion and exclusion criteria that must be verified during a screening appointment.

Typical eligibility requirements include:

1. Histopathologic or Cytological Confirmation

Before enrollment, the patient's diagnosis must be definitively confirmed via laboratory diagnostics. For oncology trials, this usually requires a biopsy with histopathology or a fine-needle aspirate with cytology. If the trial requires a specific tumor subtype, advanced tests like flow cytometry, immunohistochemistry, or PARR (PCR for Antigen Receptor Rearrangement) may be required. For example, a trial evaluating a B-cell-targeted lymphoma drug will exclude T-cell lymphoma cases, which makes immunophenotyping a mandatory screening step.

2. Tumor Stage and Location

Many trials target specific stages of disease. An immunotherapy trial for osteosarcoma in dogs might require that the dog has undergone surgical amputation of the primary bone tumor and completed standard chemotherapy, with no visible metastatic spread (spread to the lungs) at the time of enrollment. Conversely, other trials might specifically target patients with measurable, advanced metastatic disease.

3. Prior Treatment History

This is one of the most common reasons pets are excluded from clinical trials. Many studies require that the patient has received no prior chemotherapy or radiation therapy (a "naive" patient), because prior treatments can make the tumor cells resistant to the investigational drug and confound safety data. Additionally, a patient must typically undergo a "washout period" of two to four weeks if they have recently taken certain medications, such as immunosuppressants or long-acting steroids.

4. Organ Function and Performance Status

Patients must have adequate organ function to tolerate the investigational agent. Screening diagnostics—such as a complete blood count (CBC), serum chemistry, and urinalysis—must demonstrate that the liver and kidneys are functioning normally and that bone marrow parameters are adequate. Studies also use a clinical scoring system (such as the modified ECOG performance status) to ensure the pet has a reasonable life expectancy (often at least 4 to 12 weeks) and is not in terminal distress.

5. Geographic Proximity and Owner Compliance

Trial protocols are highly demanding, requiring frequent, precise follow-up visits for bloodwork, imaging, and drug administration. Academic programs, such as Colorado State University, often require that the pet owner lives within a specific geographic range (e.g., within 150 miles of the teaching hospital) or is willing and able to travel to the clinic on short notice. If a protocol requires weekly visits for six months, an owner's inability to comply with this schedule will disqualify the patient.

Is a veterinary clinical trial free, and what costs do owners still pay?

One of the most persistent misconceptions among pet owners is that clinical trials represent a "free" path to veterinary care. While some trials are fully funded, the Veterinary Cancer Society (VCS) explicitly warns that trials are not always free and that the division of financial responsibility varies dramatically depending on the study's sponsor and funding level.

When evaluating a trial, the financial structure generally falls into one of three categories:

Fully Funded Trials

Typically sponsored by large pharmaceutical companies or federal grants (such as the NCI COTC), these studies cover:

• The cost of the investigational drug or treatment.
• All study-specific diagnostic tests (e.g., repeating bloodwork, CT scans, or ultrasounds at specified intervals).
• The veterinary team's time during study visits.
• Treatment of any adverse events (side effects) directly caused by the study drug, up to a specified cap.

Partially Funded Trials

Commonly sponsored by university departments, private foundations, or non-profit organizations. In these trials, the sponsor may provide:

• The experimental drug at no cost.
• A financial credit (e.g., $1,000 to $3,000) applied toward the patient's hospital bill.
• Owners remain responsible for all other costs, including initial screening diagnostics, supportive care medications, hospitalization, and routine veterinary fees.

Non-Funded / Registry-Only Trials

Some studies are observational or evaluate new combinations of existing, approved drugs. In these cases, the sponsor does not cover clinical costs. The value to the owner is accessing a highly structured treatment protocol monitored by specialists, but the owner pays standard clinical rates for all diagnostics and treatments.

The Hidden Costs of Clinical Trials

Even in a fully funded trial, owners must prepare for out-of-pocket expenses that are rarely covered by study grants:

• Initial Screening Costs: Before a pet is accepted into a trial, the owner must pay for the initial consult and the staging tests (bloodwork, radiographs, ultrasound) required to prove the pet is eligible. If the pet is screened and found to be ineligible, the owner must absorb these diagnostic costs, which can range from $500 to $1,500.
• Standard Treatment Interventions: If a trial evaluates an adjuvant therapy (such as a vaccine given after surgery), the owner must pay for the primary standard therapy. For example, in an osteosarcoma trial, the owner typically pays for the leg amputation and initial carboplatin chemotherapy, which can cost $5,000 to $10,000, before the trial funding begins. For standard oncology cost benchmarks, see our guide on the cost of dog cancer treatment.
• Travel, Lodging, and Time Off: Frequent visits mean significant fuel costs, potential hotel stays near the university clinic, and lost wages from taking time off work to attend scheduled appointments.
• Unrelated Medical Care: If the pet develops a condition unrelated to the trial (e.g., a skin infection or a minor injury), the diagnostic and treatment costs are the owner's responsibility.

What questions should I ask before enrolling my pet in a trial?

Before consenting to enroll your dog or cat in a veterinary clinical trial, it is essential to have an open, detailed discussion with the primary investigator or trial coordinator. Use the following checklist to guide your decision:

1. Trial Design and Protocol

• What phase is this clinical trial, and has this drug been tested in this species before?
• What is the schedule of visits, and exactly what happens during each visit?
• How is the drug administered? Is it an in-clinic injection, or an oral medication I must administer at home? (If it is an oral chemo drug, you must follow strict safety handling protocols, similar to those discussed in our review of Laverdia for dogs).
• What is the duration of the study, and what is the long-term follow-up schedule?

2. Randomisation and Control Groups

• Is this a randomized or blinded study?
• Is there a control group, and could my pet receive a placebo or standard therapy instead of the investigational drug?
• If my pet is randomized to the control group or place on a placebo, is there a 'crossover' option that allows them to receive the active drug if their disease progresses?

3. Financial Agreement

• What specific costs are covered by the trial grant, and what is my out-of-pocket responsibility?
• Am I responsible for the cost of the initial screening and staging tests if my pet is disqualified?
• If my pet experiences a severe side effect that requires emergency hospitalization, who pays for that care and is there a funding cap?
• Is there a diagnostic subsidy or financial credit applied to my general account?

4. Safety, Monitoring, and Withdrawal

• What are the known or anticipated side effects of this investigational agent?
• What supportive care medications (anti-nausea drugs, pain medication, appetite stimulants) will be provided?
• What is the criteria for 'treatment failure' or disease progression that would cause my pet to be removed from the study?
• Can I voluntarily withdraw my pet from the trial at any time if I feel their quality of life is declining, and will that affect their ongoing care at this facility?

What are the risks and what happens if my pet is assigned to a control group?

Participating in a clinical trial carries inherent risks that must be carefully weighed against the potential benefits.

The Risk of the Unknown

By definition, investigational drugs do not have a fully established safety profile. While pre-clinical laboratory work and pilot studies offer some guidance, your pet may experience unexpected side effects, allergic reactions, or toxicities. In Phase I trials, the risk is highest because the team is actively searching for the toxic limits of the drug. Side effects can range from mild gastrointestinal upset to severe, life-threatening organ failure or bone marrow suppression.

Randomisation, Blinded Studies, and Placebos

To eliminate bias, many Phase II and Phase III trials are designed as randomized, double-blinded studies:

• Randomisation: A computer algorithm assigns the patient to either the treatment group (receiving the investigational drug) or the control group (receiving a placebo or the current standard therapy).
• Double-Blinding: Neither the pet owner nor the attending veterinary team knows which group the pet is in during the trial. This is done so that clinical evaluations remain completely objective.
• The Placebo Concern: While trials investigating life-threatening conditions rarely use a pure placebo without supportive care, some trials do compare standard care plus the new drug against standard care plus a placebo. If you are seeking a trial because you cannot afford standard care, the risk of your pet being randomized to a placebo group must be carefully discussed. Many trials mitigate this risk by offering a crossover design, where patients in the control group are switched to the investigational drug if their disease begins to progress.

Comparative Oncology: The Translational Value

It is worth noting that veterinary clinical trials do not only benefit the enrolled pet; they also provide critical data for human medicine. This field, known as comparative oncology, studies naturally occurring cancers in companion animals to develop treatments for both animals and humans.

Cancer is a significant disease burden in pets; roughly 50% of dogs over the age of 10 develop cancer. Because dogs share our environment, have intact immune systems, and develop cancers that are biologically and immunologically very similar to human malignancies, they represent a far more accurate model for cancer research than laboratory rodents. For example, approximately 10,000 dogs are diagnosed with osteosarcoma in the United States each year, and the incidence in dogs is estimated to be 10 to 50 times higher than in humans. Research conducted through the NCI Comparative Oncology Trials Consortium has directly informed the development of osteosarcoma immunotherapies, benefiting both veterinary patients and pediatric human oncology patients.

FAQ

Are veterinary clinical trials only for cancer?

No. While oncology is the most heavily represented field in veterinary clinical trials due to the high demand for cancer therapies, trials exist for many other chronic or refractory conditions. Common non-oncology trial areas include:

• Cardiology: Evaluating new drugs for feline hypertrophic cardiomyopathy (HCM) or canine degenerative mitrial valve disease (MMVD).
• Neurology: Investigating novel anticonvulsant protocols for refractory epilepsy.
• Dermatology: Testing newer monoclonal antibodies or JAK inhibitors for severe canine atopic dermatitis.
• Internal Medicine: Staging trials for feline chronic kidney disease (CKD) or novel therapeutics for canine diabetes mellitus.
• Orthopedics: Testing regenerative medicine techniques, such as stem cell therapy or platelet-rich plasma (PRP), for osteoarthritis.

Can my regular vet enroll my pet in a clinical trial?

In most cases, no. Clinical trials must be conducted under strict regulatory oversight, adhering to a specific protocol approved by an Institutional Animal Care and Use Committee (IACUC). Because of the advanced diagnostic equipment, specialized monitoring, and drug storage requirements, trials are almost exclusively hosted at academic veterinary teaching hospitals or large, multi-specialty referral centers.

However, your primary care veterinarian plays a critical role in the process. They are responsible for gathering the initial diagnostic evidence, recognizing clinical signs, staging the patient, and coordinating the referral to the trial coordinator. The trial team will keep your regular veterinarian updated, and once the study protocol is complete, your pet's routine care will transition back to your primary clinic.

What is comparative oncology and why do dog trials help human medicine?

Comparative oncology is the study of naturally occurring cancers in animals (predominantly pet dogs) and how they relate to cancer in humans. Unlike laboratory mice, which must be artificially injected with human cancer cells and lack functional immune systems, pet dogs develop cancers naturally in the same environments in which humans live.

Because canine tumors share identical histologic appearances, genetic mutations, metastatic patterns, and responses to chemotherapy with human cancers, pet dogs provide an invaluable translational model. Research on canine osteosarcoma, lymphoma, melanoma, and brain tumors helps researchers understand how human cancers behave and accelerates the drug approval process for both human and veterinary pharmaceutical markets.

Sources

• Merck Veterinary Manual. Lymphoma in Dogs (diagnosis by FNA/biopsy; flow cytometry and PARR; WHO staging; systemic chemotherapy). https://www.merckvetmanual.com/circulatory-system/lymphoma-in-dogs/lymphoma-in-dogs
• NCI Comparative Oncology Program - Open Trials (COTC). Comparative Oncology Trials Consortium current trial portfolio and translational cancer research objectives. https://ccr.cancer.gov/comparative-oncology-program/trials
• AVMA Veterinary Clinical Trials Registry. American Veterinary Medical Association animal health studies database search portal. https://veterinaryclinicaltrials.org
• AVMA News. New listings in the Veterinary Clinical Trials Registry, April 2026. Official AVMA bulletin highlighting newly recruiting studies. https://www.avma.org/news/new-listings-avma-veterinary-clinical-trials-registry-april-2026
• Veterinary Cancer Society. Clinical Trials Resources for Pet Owners and Veterinary Professionals. Standard-of-care position on eligibility, cost coverage, and travel requirements. https://vetcancersociety.org/resources/clinical-trials
• Colorado State University Flint Animal Cancer Center. Current Clinical Trials, enrollment criteria, and geographic proximity rules. https://www.csuanimalcancercenter.org/current-clinical-trials
• MIB Agents. Comparative Oncology and Canine Clinical Trials. Comparative statistics on canine vs. human osteosarcoma incidence and translational research outcomes. https://mibagents.org/research/canine-trials
• American Animal Hospital Association. 2026 AAHA Oncology Guidelines for Dogs and Cats. Clinical workflows for primary-care diagnosis, staging, supportive care, and oncological referral. https://www.aaha.org/resources/2026-aaha-oncology-guidelines-for-dogs-and-cats