Internal Medicine

Photo: Clinical Trial Flyer for Diabetic Remission in Cats

Feline Infectious Peritonitis (FIP)

The clinical trial for Feline Infectious Peritonitis (FIP) is no longer ongoing. Please see Dr. Pedersen's letter to owners and referring veterinarians for additional information about next steps. 

Below, please find links to all of the clinical trials involving internal medicine. The studies include a multitude of information, including (but not limited to) the study’s purpose, benefits for participating, and financial incentive information. If you have any questions, please contact the individual outlined at the end of each trial summary.

Please visit the Internal Medicine service on the Veterinary Medical Teaching Hospital (VMTH) website if you would like to learn more about the amazing things that our veterinarians can do for you and your animal.

Horses & Ponies

Equine Multinodular Pulmonary Fibrosis (EMPF): Assessing Viral Kinetics of Valacyclovir

Title: Effect of valacyclovir on EHV-5 viral kinetics in horses diagnosed with EMPF

Purpose of Study: Equine multinodular pulmonary fibrosis (EMPF) is a recently reported sporadic, progressive and fibrosing interstitial lung disease of adult horses. There is growing evidence that EMPF is associated with equine herpesvirus-5 (EHV-5). Histopathological results coupled with positive EHV-5 by qPCR on pulmonary tissue are considered the current gold standard for EMPF diagnosis. Valacyclovir, an anti-herpetic drug, is routinely used to treat horses with EMPF. The effect of this anti-herpetic drug has not been determined in regard to its capability to reduce viral loads of EHV-5 in blood, nasal secretions and bronchoalveolar lavage fluid. Due to the costs of the drug, it is imperative to determine if the drug has an antiviral effect against EHV-5.

Contact: Contact Dr. Nicola Pusterla at or Dr. Charlotte Easton-Jones at 

Participation Requirements: Horses diagnosed with EMPF based on a lung biopsy

Initial Evaluation for Participation: The case can be referred to the UC Davis Veterinary Medical Teaching Hospital once full diagnostic work-up has been completed or the case can be worked-up at the VMTH. Costs for the diagnostic work-up will be assumed by you (clinical assessment, minimal data base (CBC and biochemical panel), chest radiographs, BALF collection and cytology, lung biopsy with histopathology). Costs for EHV-5 testing will not be charged to you.

Procedures: If you agree to let your horse participate in this study, the following will happen:

  • Your horse will receive valacyclovir tablets provided by the researchers for 10 days. Blood and nasal secretions will be collected daily during the 10 days of valacyclovir treatment.
  • Immediately following the 10-days of oral valacyclovir treatment and 30 days post-treatment, you will need to bring your horse in for re-examination, blood and nasal secretion collection, and bronchoalveolar lavage.

Benefits: The study will cover the valacyclovir treatment and costs associated with the testing for EHV-5, recheck examinations with blood work and BALF analysis.

We cannot promise any benefits to your horse taking part in this clinical trial; however, the results of this longitudinal study will help us determine if valacyclovir has a beneficial effect on the EHV-5 viral loads in blood, nasal secretions and bronchoalveolar lavage fluid. This information is very important to improve the treatment of EMPF.

Owner Responsibilities: The daily collection of blood and nasal secretions can be performed at the VMTH while the horse is hospitalized or at the location where the horse is stabled if the referring veterinarian and/or you are willing to collect the samples. You will need to bring your horse back to the VMTH for the follow-up collection (at the end of the 10-day valacyclovir treatment and 30 days later).


Diabetic Remission: Assessing a New Therapy for Maintaining Remission

Title: Exenatide Extended-Release for extending remission time in diabetic cats

Purpose of Study: The purpose of this study is to evaluate the benefit of Exenatide-ER for maintaining diabetic cats in remission (in an insulin-independent state).

Contact: Dr. Chen Gilor at or 530-752-1393 to make an appointment

Participation Requirements: 

  1. Inclusion Criteria: Cats that are in good body condition (i.e., not underweight) and diagnosed as diabetic with a recent onset of remission according to the following criteria:
    • Previous diagnosis of diabetes mellitus based on clinical signs and a high serum fructosamine
    • Treated with insulin (any type) for at least 2 weeks
    • Has not required insulin treatment for at least 4 but no more than to 12 weeks
    • Has no current evidence of diabetes relapse (normal serum fructosamine and no clinical signs such as increased drinking, urination or appetite)
    • Your cat must be routinely fed a diabetic diet (a high protein, low carbohydrate diet such as Hill’s m/d, Purina DM etc.).
  2. Exclusion Criteria: Cats -
    • Recently given (within the last 2 months) oral hypoglycemic agents
    • With significant concurrent disease (any disease that may require exogenous steroid administration, reduce life-expectancy to <12 months or require intensive management, e.g. gastrointestinal, pulmonary, cardiac, hepatic, neoplastic, or renal disorders [CKD IRIS Stage 3 or higher])
    • With overt evidence of peripheral neuropathy (plantigrade stance, inability to jump), acromegaly and/or untreated hyperthyroidism. Cats will not be excluded if they have controlled hyperthyroidism or are receiving methimazole and/or ACE-inhibitors.

Initial Evaluation for Participation: Blood tests (complete blood count, biochemistry panel, serum fructosamine concentrations T4, spec fPLI and IGF-1) and urinalysis

Procedures: If the exams, tests, and procedures show that your pet can take part in the study, and you choose to enroll them, then the following will happen as part of the study:

  • Randomly placed into one of the two treatment group: Exenatide-ER (Bydureon®) or placebo. After receiving the first injection (of exenatide-ER or placebo) we will schedule your next recheck for the next month (in 27-32 days).
  • At each monthly recheck, a blood sample will be drawn to measure blood glucose levels and if needed, serum fructosamine.

Benefits: The study will pay for one third of the cost of the first office visit as well the full cost of screening tests (including urinalysis and blood tests – CBC, Chemistry, Total T4, spec fPLI and IGF-1) as well as all drug expenses and all follow-up visit expenses. After every recheck exam that you bring your cat in, the study will give you a $35 gift card (for a maximum total of $805).

Participation in this trial may help to increase duration of remission (i.e. increasing the time until diabetes relapses and your cat becomes dependent again on insulin injections), increase numbers and improved function of cells that secrete insulin in the pancreas, and help with weight loss (if your cat is over weight).

Owner Responsibilities: If you wish to have your cat participate in this study, you will be responsible for bringing your cat in to be rechecked once a month until your cat is no longer in remission for up to 24 months.

Printable Flyer (PDF)

Feline Upper Respiratory Tract Disease: Understanding the Disease

Title: Efficacy of famciclovir for control of clinical manifestations of feline upper respiratory tract disease

Purpose of Study: The purpose of this study is to evaluate the utility of a new technique called quantitative PCR (qPCR), which measures the number of viruses and bacteria in the nose, to identify a role for these organisms in cats diagnosed with feline upper respiratory tract disease. We also aim to evaluate the efficacy of famiclovir in combination with standard therapy with an antibiotic for treatment of upper respiratory tract disease.

Contact: Contact Dr. Lucy Kopecny for details at or call (530) 752-1393 to make an appointment

Participation Requirements: Kittens with acute upper respiratory tract disease displaying signs of sneezing, ocular or nasal discharge for less than 3 weeks that have not received prior treatment

Initial Evaluation for Participation: The investigators will determine eligibility for inclusion in the trial following consultation.

Procedures: If you agree to let your cat participate in this study, the following will happen:

  • Prior to treatment – Completion of a survey about your cat’s clinical signs, sample collection from the eyes and mouth using a Q-tip
  • Treatment – Oral administration of an antibiotic (doxycycline) alone or in combination with an antiviral drug (famciclovir) for 3 weeks. During this time, you will be asked to score the severity of your cat’s clinical signs daily
  • 3 weeks post treatment – Completion of a survey about your cat’s clinical signs, sample collection from the eyes and mouth using a Q-tip

Benefits: The study will cover costs associated with the quantitative PCR, medications, and visit costs to obtain samples.

Results from this study may help to identify the most appropriate diagnostic tests to use in this disease process and optimal treatment of affected cats.

Owner Responsibilities: You will be responsible for bringing your cat to all scheduled appointments, completing the surveys and administering medication twice daily during the 3 weeks of treatment.

Printable Flyer (PDF)

Fungal Disease: Examining a Treatment

Title: Voriconazole efficacy in cats with fungal disease

Purpose of Study: Voriconazole is a broad spectrum anti-fungal that is the treatment of choice for systemic aspergillosis in people and also used for variety of other fungal diseases. Drug treatment options in cats are limited because of little information of effect of anti-fungal medications on cats. The purpose of this study is to examine the efficacy of voriconazole against serious systemic fungal diseases like aspergillosis, cryptococcosis, sporotrichosis, histopalsmosis and others.

Contact: Dr. Jane Sykes at or (530) 752-1393

Participation Requirements: Cats with fungal disease that did not respond to existing anti-fungal options (e.g., fluconazole, itraconazole, amphotericin B) or did not tolerate the adverse effects of the above-mentioned medications

Initial Evaluation for Participation: An appointment with the VMTH Internal Medicine service

Procedures: If you agree to let your cat participate in this study, the following will happen:

  • Your cat will be treated with voriconazole by mouth on day 1, and then again every third day.
  • On days 14, 30, 60 and 90 of treatment and then every 60-90 days until exit from study, we will do a physical examination and collect blood to measure voriconazole levels and test liver function.
    • NOTE: If your cat will require dose adjustments, he/she may need to be seen more frequently for blood sampling and rechecks.
  • We ask that you complete a monthly questionnaire and keep a journal to document any adverse effects that occur during the period of the trial.
  • In the unfortunate event of death, we will request that you will allow us to perform a necropsy of your cat (free of charge).

Benefits: Results from this trial may lead to a better disease outcome for your cat since voriconazole is a very efficacious and broad spectrum anti-fungal medication, and cats worldwide being treated with this medication.

Owner Responsibilities: If you allow your cat to participate in this study, you will be responsible for filling out a questionnaire once a month, recording all adverse effects in a journal, and keep all scheduled appointments. You will be responsible for covering all aspects of the care for your pet.

Ureteral obstructions: Evaluating Post-Surgery Outcomes

Title: Evaluation of Post-operative Outcome in Cats Undergoing Ureteral Stent Placement to Relieve Ureteral Obstruction

Purpose of Study: The purpose of this project is to record the intra-operative and postoperative complications associated with the procedure and determine the outcome of the procedure based on objective measures.

Contact: Dr. Culp at or (530) 752-1393

Participation Requirements: Cats with benign ureteral obstruction

Initial Evaluation for Participation: Contact Dr. Culp for details at or (530) 752-1393

Procedures: Cats with a diagnosis of benign ureteral obstruction will be enrolled in the study. Bloodwork values that can be utilized to determine the function of the kidney (should improve with the passage of urine) as well as variables such as the size of the kidney collecting system and ureter (should decrease with passage of urine) in cats both pre- and postoperatively will be evaluated. Lastly, the change in the urine output of cats with ureteral stents will be assessed to determine if the stents improve output.

Benefits: Some of the pre- and post-stent placement bloodwork and pre- and post-stent placement ultrasound evaluations will be paid for by the study.

If this therapy proves to be beneficial, it will have important clinical applications for other cats with the same condition.

Owner Responsibilities: You are responsible for returning with your cat 2 weeks and 3 months after stent placement.

Read about Googgie, a 17-week-old Sphynx, that was helped by participating in this trial!


Hypothyroidism: Evaluating Current Treatment Strategies

Title: Crossover clinical study to evaluate two doses of levothyroxine for thyroxine replacement therapy in hypothyroid dogs

Purpose:  Hypothyroidism is a commonly diagnosed hormonal disease in the dog. Thyroid hormone supplementation is the treatment of choice for this disease and is routinely started at a dose of 0.02 mg/kg administered every 12 hours. Recent clinical experience suggests that some dogs may respond to lower doses of thyroid hormone supplementation. We are currently investigating whether dogs with hypothyroidism can be successfully treated using a lower dose of thyroid hormone and the best way to monitor this treatment.

Contact: Dr. Sean Hulsebosch at 

Participation Requirements: Dogs diagnosed with hypothyroidism

Initial Evaluation for Participation: None.

Procedures: If you are willing to have your dog participate in this study, the following will happen:

  • You will need to administer one dose of thyroid hormone orally twice a day for a month.
  • A month after initiating treatment, you will need to bring your dog back to the VMTH to spend a 12-hour day in the hospital. During this time, we will be obtaining a blood sample upon arrival, and then multiple blood smaples through the day following administration of the thyroid hormone.
  • A new 30-day supply of thyroid hormone supplement will be dispensed. You will need to administer this dose twice a day for one month. The same blood sampling will be performed 30 days later as outlined above.

Benefits:  If you choose to enroll your dog, the study will cover the cost of all tests discussed above (thyroid panel, additional subsequent TSH and T4 levels for two months while enrolled in the study), and day case hospitalization. Upon completion of the study, a six month supply of thyroid hormone supplement at the appropriate dose for your dog will be dispensed to you and covered by the study.

Results from this study may help to improve assessment and treatment of hypothyroidism and allow for a customized dose adjustment thereby preventing unnecessary overdosing of medication.

Owner Responsibilities: If you allow your dog to participate in this study, you will be responsible for:

  • Giving oral thyroid supplementation at home twice daily (every 12 hour)
  • Bringing your dog in for the scheduled study visits
  • Covering the cost of the initial exam and any necessary lab work deemed necessary to determine if your dog is eligible

Printable Flyer (PDF)

Cystine Bladder Stones: Investigating an Oral Nutraceutical Treatment

Title: The effects of an oral nutraceutical on the solubility of cystine in canine urine


  • Cystine bladder stones are common in both dogs and humans. This disease occurs due to a genetic predisposition, which occurs in many breeds of dogs. Therapeutic preventive strategies are limited.
  • Clinical signs can be mild or result in urethral obstruction in male dogs.
  • In a collaborative effort between the University of California San Francisco and The Buck Institute, the aim of this study is to evaluate the effects of an oral nutraceutical on cystine solubility in the urine.

Contact: Jodi L. Westropp DVM PhD DACVIM at, Sean Hulsebosch DVM DACVIM at, or make an appointment by calling (530) 752 – 1393.

Participation Requirements:

  • Dogs with a history of cystine stones
  • Healthy dogs with no history of cystine stones of similar breeds

Initial Evaluation for Participation: Known documented history of cystine stones


  • A physical exam, abdominal ultrasound, blood and urine testing will be performed.
  • No follow-up visits will be required; however, urine samples will need to be collected at home after receiving the oral nutraceutical for one week.


  • Free screening and diagnostic testing for your pet, including abdominal ultrasound, bloodwork and urinalyses
  • We hope that the data acquired in this study will allow us to advance the prevention of cystine bladder stones in both pets and people.

Owner Responsibilities:

  • Keeping the scheduled appointment
  • Administering the oral nutraceutical for 7 days
  • Three, at-home urine collections while administering the medication to your dog

Printable Flyer (PDF)

Urinary Incontinence: Using a New Device for Treatment

Title: Use of radiofrequency urethral thermoplasty for the treatment of urinary incontinence

Purpose: Medical therapy using either phenylpropanolamine or synthetic estrogen, alone or in combination is currently considered first line medical therapy for urinary incontinence. While studies have shown that these medications are effective in some patients, both have potential side effects and life-long therapy is generally required. Various surgical treatment options have also been described for those dogs that do not respond to medical management or experience adverse effects from medications; however, these procedures are invasive, require considerable surgical skill to perform and are not always successful. Therefore, the purpose of this study is to test a new device, which uses heat to alter the structure of collagen in the wall of the urethra and thereby strengthen the wall and decrease leakage), to treat urinary incontinence in female dogs.

Contact: Dr. Bill Culp (, Dr. Carrie Palm (cpalm@ucdavis.eduor make an appointment by calling (530) 752-1393

Participation Requirements: Female dogs demonstrating signs of urinary incontinence

Initial Evaluation for Participation: To be performed by Dr. Palm or Dr. Culp


  • Testing related to urinary incontinence, including bloodwork, abdominal ultrasound and possibly cystourethroscopy (camera evaluation of the urethra and urinary bladder)
  • Urethral procedure under general anesthesia once your dog is deemed a candidate

Benefits: The study will cover costs associated with anesthesia, the urethral procedure and hospitalization.

We hope that the data acquired in this study will allow us to advance the treatment of our canine patients.

Owner Responsibilities: This study requires 1-year time commitment, although future follow-up may be recommended. You will be responsible for covering costs associated with initial diagnostics including bloodwork, abdominal ultrasound and cystourethroscopy, keeping all scheduled appointments and follow-up visits, and filling out a urination diary throughout the study.

Printable Flyer (PDF)

Fungal Infections (Aspergillus spp) in German Shepherds, Rhodesian Ridgebacks, and Hungarian Vizslas

Title: Genetic analysis of the susceptibility to systemic Aspergillus infections in dogs

Purpose: Systemic fungal infections such as aspergillosis are rare in animals with a competent immune system; however, certain dog breeds (namely the German shepherd, Rhodesian ridgeback and Hungarian vizsla) are reported to have a higher risk of this uncommon disease. A genetic etiology is suspected to cause this over-representation. We propose to use a technique called genome-wide association analysis to evaluate the differences in the genetic material of affected dogs (dogs infected with Aspergillus spp.).

Contact: Dr. Jonathan Dear, DVM, DACVIM at

Participation Requirements:

  • German Shepherds with systemic Aspergillus spp. infections
  • Rhodesian Ridgebacks with systemic Aspergillus spp. infections
  • Hungarian Vizslas with systemic Aspergillus spp. infections

Initial Evaluation for Participation: None.

Procedures: The only procedure required is the collection and submission of a blood sample for DNA extraction. For more information about submitting samples, please contact Dr. Jonathan Dear (details above).

Benefits: Results from this study will hopefully lead to the development of DNA tests that would identify dogs at risk for developing systemic aspergillosis. These tests would help simplify the diagnosis of the disease by identifying at risk individuals and allow breeders to avoid producing affected dogs. Furthermore, if the genetic traits responsible for this disease in dogs are shared with human patients, precision medicine can be used to help develop targeted therapies to treat this life-threatening disease.

Owner Responsibilities: You or the referring veterinarian needs to collect and submit a blood sample and medical records.

Printable Flyers

  • German Shepherds (PDF)
  • Vizslas (PDF)
  • Rhodesian Ridgebacks (PDF)
Cushing's Disease (Hyperadrenocorticism): Improving Diagnostic Values

Title: Evaluation of post-dexamethasone cortisol value used to diagnose hyperadrenocorticism in dogs

Purpose of Study: The cut off values previously used to diagnose hyperadrenocorticism, or Cushing’s disease, were first determined over 30 years ago. Since then, there have been significant advancements in laboratory equipment and techniques as well as the clinician’s ability to identify this disease as a differential diagnosis. The goal of this study is to re-evaluate the cut off values used to diagnose hyperadrenocorticism in dogs.

Contact: Dr. Sean Hulsebosch (  or Dr. Laura Lim or (

Participation Requirements: Adult dogs suspected to have hyperadrenocorticism (Cushing’s disease; either pituitary or adrenal dependent) prior to receiving any medical therapy.

Initial Evaluation for Participation: An appointment with the VMTH Internal Medicine Service will be necessary to confirm eligibility for study, please note to reception staff that you are interested in this study.

Procedures: If you agree to let your dog participate in this study, the following will happen:

  • Day 1: We will collect a blood and urine sample for analysis, assess blood pressure, and need you to collect two urine samples from your pet at home prior to arrival and bring these with you. These samples should be collected first thing in the morning for two consecutive days prior to arrival, and kept refrigerated. You will be required to complete the study questionnaire. This can be performed with initial appointment or an initial assessment and consultation can be performed with you to schedule an additional visit for enrollment and sample collection.
  • Day 2: We will perform an ACTH stimulation test and an abdominal ultrasound.
  • Day 3: We will perform an 8-hour low-dose dexamethasone suppression test which requires a 8-12 hour fast.
  • We may contact you or your regular veterinarian in the future by telephone or email to follow-up on your dog and request that you schedule an appointment for recheck.

Benefits: Dogs suspected to having hyperadrenocorticism will assist in evaluation of cut off values used to make a diagnosis of hyperadrenocorticism. The study will cover the cost of the abdominal ultrasound, one of the urine cortisol creatinine ratios, endogenous ACTH level, ACTH stimulation test, low dose dexamethasone suppression test, and cost associated with hospitalization during the day. 

Owner Responsibilities: We expect that participation in this clinical trial will last for a total of 3 (non consecutive) days. Testing must be performed before any treatment is initiated. You will be responsible for keeping all scheduled appointments and covering the cost of the treatment of hyperadrenocorticism, initial examination, initial laboratory evaluation (CBC, chemistry panel, urinalysis and urine culture), urine cortisol creatinine ratio, blood pressure, along with any additional testing recommended by the clinician managing the case. These tests would be standard in evaluation of any dog suspected to have hyperadrenocorticism.

Printable Flyer (PDF)

On Hold Until Further Notice

Variety of Tumors: Assessing Minimally Invasive Tumor Ablation in Dogs and Cats

Title: Thermal ablation of cancer

Purpose of Study: The purpose of this study is to evaluate the outcome of treating veterinary patients with minimally invasive tumor ablation technologies including cryoablation and microwave ablation. These methods are growing in the treatment of a variety of cancers in the human medical field, but information in veterinary patients is currently very limited. To date we have completed a study on cryoablation in nasal tumor patients, and this technique has been very successful in reducing tumor volume in nasal tumor patients – although there are no more spots in the formal nasal tumor study, because of this success, we continue to offer this technique as a clinical service to nasal cancer patients, and are expanding the types of cancer that we are evaluating.

Variety of Tumors and Diseases: Improving Operative Detection of Tumors in Dogs and Cats

Title: Fluorescent imaging of cancer

Purpose of Study: Near-infrared fluorescent imaging utilizes special wavelengths of light to identify important structures, and is used in surgery to improve surgical decision making. The fluorescent light is generated by a special contrast agent (a “fluorophore”) that is injected into the patient. When a special light source is used to illuminate the surgical site, any tissue in which this fluorophore is located will glow, aiding the surgeon in identifying the location or extent of disease. Based on early experiments in rodents and human clinical trials, this very sensitive tool has the potential to improve surgical decision-making and improve overall treatment for a wide variety of diseases. The purpose of this study is to evaluate the efficacy of this imaging modality in veterinary patients presenting with naturally occurring neuroendocrine tumors disease processes.

Inflammatory Bowel Disease: Evaluating a Stem Cell Therapy in Dogs

Title: Immunomodulation by Mesenchymal Stem Cells In Canine Inflammatory Bowel Disease

Purpose of Study: Inflammatory bowel disease (IBD) in dogs often involves lifelong steroid therapy, which holds the risk for a variety of potentially serious complications. Because of the ability to regulate immune responses and facilitate tissue regrowth or repair, we believe that fat-derived, mesenchymal stem cells (MSCs) may help to decrease the abnormal immune response and the accompanying inflammation. Therefore, the purpose of this study is to investigate the effectiveness of a new stem cell therapy for canine IBD and better understand how stem cells work to limit inflammation and repair gut tissue.

Ectopic ureters: Evaluating Laser Ablation as a Treatment Option in Dogs

Title: Evaluation of the Use of Cystoscopic-Guided Laser Ablation in the Treatment of Canine Ureteral Ectopia

Purpose of Study: To evaluate urethral pressure profiles (UPPs) in patients undergoing laser ablation of their ectopic ureters. The goal is to determine if pre-treatment UPP values can help to predict continence rates after laser ablation.

If you cannot find what you are looking for, please email us or call (530) 752-5366.