diaTribe talked quite a bit about the Artificial Pancreas on Wednesday and so did Stu Weinzimer & Ed Damiano from JDRF on Thursday. I skipped Wednesday's session because of arriving late & missed the Thursday session because of Will's eye, but Gene attended both. This post comes from my understanding, Gene's handouts, and the FDA's website.
An artificial pancreas pairs the continuous glucose monitor & insulin pump like the ones that Andrew already wears with a control algorithm that makes changes to his insulin delivery as the data comes in. We already have experimental versions of this. Many trials ask the patient to control their diabetes with set portion sizes and activity one day and then allows the computer to control insulin delivery with the same food & activity the next. The computer algorithm consistently outperforms people. However, the trials are still highly supervised in a hospital setting. They may be moving to a clinical setting, and we will know we are making progress when they get approved for home trial.
There is some danger in giving technology control over insulin delivery when too much insulin or too little insulin can be so dangerous so quickly. The FDA in June 2011 issued a statement of support of developing an artificial pancreas and provided guidelines to companies seeking to develop one. There will be several types of artificial pancreas device systems. The first is a reactive low glucose suspend system. When the cgm detects very low blood sugars and no response from the user, it suspends insulin delivery. It's primary function is to save lives of people who are really low and asleep or passed out and unable to respond to the low. Since we have a system in place to wake me when Andrew is low, I don't expect this first stage to help Andrew's glucose control at all. It will be an important first step in beginning to trust the cgm technology and will mean the next few steps are on the way. A predictive low glucose suspend system will antipate lows and temporarily suspend insulin to prevent lows. Since low blood sugars often rebound to highs, preventing lows would improve patient control and take away some of the fear of embarassing low blood sugars.
I'm even more excited about the treat-to-range or treat-to-target systems. The treat-to-range system system not only prevents lows but prevents high blood sugars as well. You specify the blood sugar range you wish to stay between and the pump dispenses more or less insulin as you approach the high or low end of your range. According to the FDA descriptions, these pumps would still require the patient to check blood sugars & bolus for meals. This sounds to me like what we once told would be a "minimizer" pump, but I don't really hear that terminology much anymore. The treat-to-target systems would be fully automated, requiring no boluses or carb counting. You would calibrate the CGM twice a day with a finger prick & then go about your day staying in target. Is this possible? Yes! Currently, trials are achieving 70%+ time in target with often 90%+ overnight control. The data I saw (See the Future of the Cure Post) showed the patient going slightly over 200 after eating & not bolusing and hitting 68 after exercising and only eating salad for lunch. That was still better than what he did on his own under the same conditions.
The FDA already envisions three types of treat-to-target systems. The first is insulin only, which just adjusts insulin amounts to achieve the results. This is working now in trials & would work even better with faster acting insulin. However, our bodies use a combination of insulin and glucagon to control our glucose levels, so scientists are beginning to conceive of bi-hormonal pumps that give insulin to treat high glucose levels and faster-acting glucagon or similar hormone to raise low glucose. It will take longer to approve through the FDA since there is no currently approved glucagon pump. The last treat-to-target system is a hybrid system that while still fully automated, allows patients to supplement insulin pre-meal to prevent post-meal spikes. I like this idea. Currently, cgms measure interstitial fluid which lags behind blood glucose by about 10 minutes. Then boluses of insulin take about 15 minutes to absorb and start working. So, in an automated system, the insulin would begin working about 25 minutes after ingesting the carbs. Pre-bolusing is important now, so I like the idea of keeping the capability.
Rumor has it that Dexcom has a new CGM that is smaller & more accurate that is pending FDA approval. Insulin pumps have already been approved, so that isn't an obstacle. I don't see anything new coming out until we see the new, more accurate sensors approved. I expect to see low glucose suspend systems next, etc.
Is the artificial pancreas a cure? NO!!! Andrew already wears a pump and a cgm, and I have seen both fail. Being connected to life support is not a cure. I have even seen angry posts from patients toward JDRF for investing so much into the artificial pancreas. I don't agree with them either. I want a cure! In the meantime, however, God has allowed Andrew to have type 1 diabetes. We have to do the best we can to manage it. Andrew already wears the pump and the cgm. Would I like them to talk to each other and prevent those high and low blood sugars that take their toll on his little body? YES! Insulin isn't a cure, but a treatment, but I'm so glad to have it and to see Andrew alive and healthy. The artificial pancreas won't be a cure, but I'd be so glad to have it and to see Andrew alive, healthy, in range, not afraid of lows, and at less risk for the complications of diabetes that come from high blood sugar! So, in my opinion, bring on the artificial pancreas!
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