Iris is currently participating in a clinical trial. The clinical trial is a regimen of a medication called miglustat (Zavesca) in combination with the ketogenic diet. All the other clinical trials are either observational only or involve bone marrow transplant. The one team we spoke to with respect to a bone marrow transplant required asymptomatic patients. Unfortunately, Iris is not in that category of patients. For our family, we are also not sure we would have chosen that path.
Miglustat is FDA-approved for Gaucher disease, another lysosomal storage disease that affects the brain. The basis of the trial is threefold. Miglustat is believed to possibly be more effective in combination with the ketogenic diet, perhaps as much as 300% more effective. This belief is based off a single research study in rats. The ketogenic diet is also used to control seizures. Many GM1 patients suffer from seizures. As of now, Iris is very fortunate to not have seizures. The diet is also used to mitigate the gastrointestinal side effects of miglustat.
To be clear, some clinical trials are successful and some are not. There is a reason it is called a trial. Furthermore, this specific protocol is not universally accepted. We are very happy to participate in the trial. There’s really nothing else to try. We are hopeful that the regimen is helping Iris. However, it’s not a cure. Hopefully, it’s a way to buy time until a true cure or another treatment emerges.
In our own experiences with the regimen, Iris did cease toe-walking after initiating treatment. However, we had also increased physical therapy at the same time. We thought that her walk possibly improved. Then, other symptoms emerged. Her gait changed in different ways and not for the better. We also thought that her speech might have improved for a bit, but that also can come and go.
There are 2 aspects of the trial that have clear evidence. Limiting carbohydrates does relieve the gastrointestinal side effects. The ketogenic diet is proven to help some people with seizures. It’s been used for quite some time for that purpose separately from this particular study. In general, there are so few patients to verify results. It can also be difficult for the patients to participate in studies in distant locations. Some other GM1 families told us the regimen helped their children, but the evidence is primarily anecdotal at this point.
Technically, Iris is in ketosis, so the diet she follows is ketogenic. However, we achieve ketosis through the Modified Atkins diet. This is a different approach from the more complicated true ketogenic diet involving ratios of fat and protein and calorie counts. So far, we have been fortunate because Iris seems to be able to tolerate Modified Atkins.
She is allowed 15g of carbohydrates a day. To put that in perspective, 1 teaspoon of sugar has 4.2g of total carbohydrate. All the carbs Iris consumes are from fruit and vegetables only. Yes, vegetables have carbs. Low carbohydrate is not the same as gluten-free. This means there is basically never dessert at our house. There is no bread basket. There are no ice cream sundaes, no Halloween candy, and no chocolate bunnies. There is not even true birthday cake. There are ketogenic cream puffs. If we make any sweet at all, it is prepared using a sweetener such as Stevia. The ketogenic diet can cause weight loss and that’s the last thing GM1 kids need. To avoid weight loss, the diet incorporates lots of fat to balance the absence of sugars or carbohydrates.
Iris’ brother Carter has known the word “carbohydrate” since he was 3. Iris has followed this regimen for nearly a year by mouth. Some other children have feeding tubes and use a keto liquid formula or a blenderized diet. We travel with our own food and snacks always.
It is very difficult to establish indisputable evidence that the treatment is effective. Once a course of treatment is established, one can not know the road not taken. One world specialist in GM1 went as far to say that if it were possible to extract the brains of the patients and analyze the brain in a petri dish, it would still be hard to measure the success of the treatment. Another doctor told us that short of a complete miracle and reversal of all symptoms, there can be many gray areas. I don’t know of anyone who experienced a complete miracle, i.e., a cure for GM1, but we sure would love one!