Dr. Lunn's New Study - Finally Available

From Dr. Lunn:
Attached is the final version of the project information - feel free to post on the website.Thanks for all your help with it.
We need a total of 6 cats. Nobody has actually started on the study yet, so still plenty of openings.


Long-Acting Octreotide Therapy for Cats with Acromegaly: Project Information

This document is intended to provide more information about our study of a new medical therapy for acromegaly in cats. If you have further questions, please do not hesitate to contact Dr. Lunn:

Email: kathylunn@me.com
Office phone: 970 297 4010
Clinic phone: 970 297 5000

What is acromegaly?

Acromegaly is an endocrine (hormonal) disease of cats. It is caused by a tumor in the pituitary gland. The pituitary gland is a small gland located in the brain. The normal pituitary gland secretes many hormones that control other glands in the body. In acromegaly, a tumor grows in the pituitary gland and secretes excessive amounts of growth hormone (GH). It is the GH that causes problems for these patients. Acromegaly also occurs in humans, but is very rare in dogs. The condition was previously reported to be rare in cats, but appears to be more common than we originally thought, and many veterinarians are just beginning to learn about the significance of this disease.

What are the effects of excessive GH in cats with acromegaly?

The excessive GH levels have many effects. One of the most obvious is that GH causes “insulin resistance”. This eventually leads to diabetes mellitus. Diabetes that requires high doses of insulin and is difficult to regulate is the commonest sign of acromegaly in cats.

Excess GH levels also leads to high levels of another hormone, called IGF-1. IGF-1 causes the growth of bone, soft tissues and organs. Therefore cats with acromegaly often have large kidneys, thickening of the heart muscle, changes in the shape of their face, large feet, and noisy breathing (due to thickened tissues in the throat).

What about the pituitary tumor? Does that cause problems itself?

It is uncommon for the tumor to cause problems directly, in the early stages of acromegaly. If the tumor is large enough then it could cause headaches, lethargy and decreased appetite. If it is very large there could potentially be neurological problems such as seizures or behavioural changes. If untreated, it is likely that the tumor will continue to grow, however we do not know how many cats will develop neurological problems.

When is acromegaly suspected in cats?

Acromegaly is suspected in an older cat that has diabetes that is difficult to control. Cats with acromegaly require very high doses of insulin (10-15 units per dose, or more). The disease may also be suspected if physical changes are seen (enlarged feet, big kidneys, change in shape of the face or noisy breathing).

How is acromegaly diagnosed?

The most common test is an IGF-1 level on the blood. This test should be run at Michigan State University. There is now also a GH test. We recommend that this be run at the University of Minnesota. The pituitary tumor can be detected by CT or MRI scans.

How is acromegaly treated?

Many of our treatments are borrowed from human medicine. There are basically 3 types of treatment: surgery, radiation therapy and medical therapy. Pituitary surgery is very difficult in cats (compared to humans) and is not available in the United States at this time. Radiation therapy can be successful. At CSU we use “stereotactic radiation therapy” (SRT) and we have had good results with this. This costs around $4-5,000 for the course of 4 treatments. In humans, several different medical therapies are used, but have not been tried in cats.

What is the prognosis for acromegaly? What will happen if a cat is not treated?

In the short term, the prognosis is good. But in the long term it is poor. Cats with acromegaly usually die or are euthanized due to complications of poorly controlled diabetes. Cats with acromegaly can also develop significant heart or kidney disease that will shorten their lifespan.

What is this study about?

This study is designed to see if medical therapy can help cats with acromegaly. We are using a drug that is used to treat acromegaly in humans. We would like to have more treatment options available for cats with this disease. Although radiation therapy appears to be helpful in many of these cats, it is not available to everyone, due to location and cost. Thus it is important to begin to evaluate other possible treatments for these cats. Because this is a study, we cannot predict what the outcome will be, but we do know that the results will help us make an important step forward in understanding and managing feline acromegaly.

What is the drug and how does it work?

The drug is long-acting octreotide (called Sandostatin-LAR: http://www.sandostatin.com). This drug is a “somatostatin receptor ligand” or SRL. The SRLs bind to cells in the pituitary tumor and shut off GH production. This should decrease both GH and IGF-1 levels. In humans treated with SRLs, the pituitary tumor can shrink in some cases.

How effective is long-acting octreotide in cats?

We do not know, as it has not been tried. It is an effective treatment in some humans, although it is often combined with surgery or radiation in people. The efficacy in humans is around 70%, but it varies a lot between different studies.

How can a cat qualify for this study?

The following is a summary of the requirements for enrollment in this study:

1. The cat must have clinical signs of acromegaly (insulin-resistant diabetes and physical changes) and must have elevated IGF-1 and GH levels.
2. A CT or MRI scan are NOT required for enrollment, although they can be helpful in confirming the diagnosis.
3. The cat should not have any other significant illnesses apart from diabetes (assessed on routine blood tests and urinalysis). Certain diseases are acceptable if they are stable and well-controlled.
4. The owner of the cat must find a local veterinarian who is willing to work with CSU and who understands acromegaly (or is willing to learn about it) and diabetes management.
5. The veterinarian must be willing and able to give the medication and obtain the required follow-up blood samples.
6. The owner and veterinarian must be willing to obtain blood samples at specified times and ship the samples to Dr. Lunn for analysis.

What exactly happens in the study?

First of all, Dr. Lunn will need to review the medical record of the patient, including GH and IGF-1 levels, serum biochemistry profile, complete blood count, and urinalysis. If the patient appears to be suitable, Dr. Lunn will confer with the primary veterinarian to be sure that all follow-up can be performed. Dr. Lunn will be available throughout the study, and beyond, to assist with acromegaly and diabetes management.

The long-acting octreotide will be prepared at CSU and shipped to the veterinarian, one dose at a time. The medication is given once a month, by intramuscular injection. A total of 6 doses will be given in the study, starting at 2 mg monthly. A blood sample will be taken monthly and shipped to Dr. Lunn. This will be used to assess a serum biochemistry profile, GH, and IGF-1 levels. This will allow us to determine if the therapy is working and if there are any adverse effects.

What is the cat owner responsible for?

The owner must take their cat to their veterinarian once a month for the injection and the blood sampling. A physical examination should also be performed at each time. The owner is also responsible for notifying Dr. Lunn about any changes or concerns at any time during the study. The owner and primary care veterinarian will be provided with check-lists to ensure that the study protocol is followed. The owner and veterinarian should also agree to share medical records information with Dr. Lunn.
The owner is financially responsible for the costs of the monthly appointments with the primary care veterinarian, and the costs of any tests beyond those covered by the study. For example, the study will not pay for glucose curves or fructosamine levels. The owner is also responsible for the costs of the initial tests to determine if the cat is suitable for the study.

What is the primary care veterinarian responsible for?

The primary care veterinarian is responsible for administering the medication, performing a monthly history and physical examination, and shipping the appropriate samples to Dr. Lunn.

What will the study pay for?

The study provides the medication for 6 months. The study will pay for all shipping, including the shipping of the samples to Dr. Lunn from the primary care veterinarian. The study will pay for the monthly biochemistry, GH and IGF-1 tests.

What happens if the medication does not work?

We will know that is happening if the diabetes is still difficult to manage and the GH and IGF-1 levels stay high. We will then slowly increase the dose of the long-acting octreotide, up to a maximum of 4 mg. It is still possible that the medication will not work, even at the higher dose.

What happens if the medication does work?

We will know that is happening if the diabetes regulation becomes easier and the GH and IGF-1 levels fall. The study will last for only 6 months. Beyond that time, the purchase and administration of further medication would be the responsibility of the owner and the primary care veterinarian. The pharmacy at CSU is legally unable to provide the medication once the study is completed, unless it is for administration to a patient that attends the Veterinary Teaching Hospital at CSU.

If the medication is continued beyond 6 months, what is the cost?

The cost would be depend on the dose, but is likely to be several hundred dollars per month. Unfortunately this is a very costly drug.

What are the side-effects of long-acting octreotide?

The main side effects in humans include gastrointestinal upset (nausea, diarrhea, flatulence) and sludge or sediment in the gallbladder. We do not know what the side effects will be in cats. This will be monitored with owner observations, examinations by the primary care veterinarian, and monthly biochemistry profiles.

Will the study pay for any complications arising from the use of the long-acting octreotide?

No – the study cannot pay for the management of any complications.

Can an owner withdraw from the study at any time?

Yes. The owner has the right to withdraw their cat from the study at any time. Dr. Lunn should be notified if this is being considered. It is also possible for Dr. Lunn to remove a patient from the study if it appears that the patient is adversely affected by the medication.

Are there any financial incentives for enrollment in this study?

The study will pay for the medication, follow-up blood tests, and all shipping. There are no financial incentives beyond this.

What are the benefits of enrollment in this study?

There are basically two potential benefits to the patient and owner:
1. This medication may alleviate the signs of acromegaly for up to 6 months. Although a short time, this is significant in the lifespan of a cat, particularly if quality of life is improved.
2. Regardless of the final outcome of the study, the findings will help advance our understanding of feline acromegaly, and help all of us to towards our goal of finding more treatment options for this important condition.

 

Thanks for posting this Heather

 

Hi guys - Dr. Lunn contacted me last week and asked that I remind people about her drug trial. While people showed a lot of interest in the beginning, only one cat has actually followed through. Please consider the study - the drug has been used for people for a while (in fact, my stepmother uses the drug for her endocrine cancer). It's not a feasible solution long-term due to the expense, but it will hopefully help advance treatment options.