Treatment Options for Coats’ Disease
Medical Advisory board member Dr. Michael Jumper answers this to the best of his ability. Watch the video below.
Most patients who have severe Coats’ Disease lose blood flow to the retina. Small blood vessels known as capillaries close, and this leads to higher risk of retinal detachment and bleeding. Laser is done to treat these areas of capillary closure that can lead to neovascularization or retinal leakage. It is important to know that the laser is literally “killing” sick retina. The laser is not being used to make vision better. It is preventive. It can only be used in patients who do not have retinal leakage so severe that it has caused retinal separation also known as serous retinal detachment. Laser is done to treat areas of capillary closure that can lead to retinal leakage. Laser can be applied in many different methods. It is used when retina specialists can locate specific areas of retina capillary closure also known as retinal ischemia. Retinal doctors use various tests including fluorescein angiogram, optical coherence tomography, and other tests to locate areas that are safe to treat. Laser cannot be delivered too intensely to the center of the retina where vision is most dependent on healthy function.
Laser and Avastin (see below) can be used separately, or in combination to treat Coats’ Disease. Laser is “permanent”, meaning that it causes death of the specific area of retina treated to achieve a longer term benefit (stopping leakage). Avastin is “temporary”, meaning that when the drug wears off, the leakage may quickly return.
Be advised that the patients who get the laser are not cured. Other areas of retina in Coats’ patient may begin to have capillary closure and lead to retinal ischemia requiring additional laser, or addition of Avastin. Laser can cause loss of vision wherever it is applied. These are called blind spots, also known in ophthalmology as scotoma. The more laser, the more risk of patients noticing blind spots.
Avastin is also known as Bevacizumab and is made by Genentech. This drug is a special medicine that blocks a receptor found on blood vessels, known as vascular endothelial growth factor (VEGF), that causes blood vessels to leak, and new blood vessels to grow (also known as neovascularization). Blocking VEGF causes blood vessels to stop leaking, and new blood vessels to stop growing until the medicine wears off. Avastin was FDA approved for patients with certain cancers/tumors because this effect could shrink the cancer without typical chemotherapy side effects. Retina doctors began using small portions of the medicine to inject directly into the eyes with patients who have retinal problems from blood vessel leakage and neovascularization, such as diabetic retinopathy and macular degeneration. Despite being approved by the FDA for cancers, Avastin is NOT approved by the FDA specifically for the eye. Patients sign a consent form allowing the retina specialist to use the drug knowing the FDA has not approved Avastin (also known as off label use).
Coats’ Disease is characterized by uncontrolled blood vessel leakage, and occasionally neovascularization. Although we don’t know the exact cause of Coats’ Disease, a common problem with the disease is blood vessel leakage. Avastin can stop the leakage and neovascularization in many patients, although the Coats disease is not cured and visual loss cannot always be restored.
Retina specialists use Avastin because if Coats’ is caught early enough, Avastin can be used. Avastin is generally thought to be very safe, and can be given quickly and without major surgery. Compared to other drugs, when given in the eye, it is also not very expensive. Other drugs that are approved by the FDA, cost thousands of dollars. Avastin, when used in individual syringes made by special pharmacies may cost less than 100 dollars
Avastin is generally thought to be very safe, and can be given quickly and without major surgery.
Avastin works. However, it all depends upon how severe the leakage is and how early the Coats Disease is found/diagnosed. Remember, Coats’ Disease does not currently have a cure. If a patient has permanent retinal damage, the Avastin may make the existing leakage go away, but not restore permanently damaged retina. Therefore, patients may not have noticeable improvement in vision. Coats’ Disease, because of its rarity, is hard to study. We don’t know percentages of who gets better and we don’t know if VEGF is produced equally in all patients with Coats’ Disease.
Avastin, when given as an injection to adults is typically safe. The biggest fears were potential stroke, but there is no clear evidence that patients are at higher risk. The procedure in which Avastin is given requires a procedure known as intravitreal injection, which can rarely (0.03-0.05% of the time) cause a severe infection within the eye, known as endophthalmitis. Finally, the long term effects of Avastin on children is unknown. Though there are no reports of direct effects, because it has not been studied formally by the FDA on children, there are potential unknowns as children grow.
The most common misconception about Avastin is that it is chemotherapy. Chemotherapy usually causes direct poisoning of rapidly dividing cells such as cancer cells, but also normal hair cells and gastrointestinal cells. Avastin is not that kind of drug and patients do not get hair loss or lose weight. The other big misconception that patients may have is that Avastin “cures” Coats’ Disease. The benefits can be temporary, and the Avastin may need to be repeated or laser given.
Other Potential Treatments
- Draining of leakage
- Removal of all or part of the eye (enucleation)
For all medical advice and to map out an effective treatment option for you, please consult a medical professional who is familiar with your case.