A small step forward
With all that’s going on in the insulin pump world, a statement that appeared in the FDA’s Devices & Diagnostics Letter may have gone unnoticed. According to an article that appeared back on June 27, 2011 entitled “FDA Suggests Endpoint Validator For LGS Artificial Pancreas”; “The FDA is recommending that readings from continuous glucose monitors (CGM) be used to determine if trials for artificial pancreas devices are reaching their endpoints, despite its concerns about the accuracy of the method in this context.”
The article goes onto state; “The agency expressed unease about making this recommendation “Although CGMs have been successful in improving diabetes management through their tracking and trending functions, these devices have not been shown to be accurate enough to support use for insulin dosing,” the guidance says.
Despite this concern, the agency sees no other alternative: “Although a precise, laboratory-based plasma glucose measurement would be ideal, monitor-based estimates (or those with a validated glucose sensor) are the only practical method,” according to the guidance.”
The article also addresses a key issue with closed-loop systems notable the Low Glucose Suspend (LGS) feature, the article states; “An LGS system can help reduce or lessen the severity of a dangerous drop in glucose levels (hypoglycemia) by temporarily limits or stopping insulin delivery. However, patients must still manage glucose levels with a glucose meter and give themselves insulin, if necessary, the FDA says.”
While Diabetic Investor remains pessimistic that a truly closed loop insulin delivery will make it through the FDA and actually be commercially viable this is good news albeit only a small bite of good news. As the article correctly points out, CGM systems are getting better but we are not yet at the stage where they can be used to dose insulin. Secondarily Diabetic Investor believes way too much is being made of the LGS feature which is now available in Europe. Here’s why –
The theory behind LGS is that the pump will shut down and not deliver any insulin therefore preventing the patient from experiencing a serve case of hypoglycemia, a life threatening event. The only problem is this theory does not always work in the real world. Just ask any patient who’s experienced a serve hypoglycemic event or what Diabetic Investor likes to call “crashing”. Yes it’s true that if LGS works it would be somewhat helpful but the fact is LGS as it is designed today would not prevent a hypoglycemic event.
The simple fact is even if insulin delivery is shut down the insulin that’s in the patient’s system continues to work, this is why pump patients must understand duration of action – basically how long does insulin work in their body. With LGS the body does not get more insulin but the insulin on board continues to work. It should also be noted that when glucose levels are decreasing at a rapid rate, i.e. crashing, shutting down insulin delivery really won’t do much.
What is really needed is a system that can predict glucose levels and adjust insulin delivery so that hypoglycemic events are prevented or at minimum the events are minimized. The best way to think of this is like the systems we have in place today that warn people of an oncoming tornado, although not perfect these systems have become more advanced and now can provide advanced warning allowing people to take shelter. As we have seen by the devastating tornado’s this year every minute of advanced warning saves lives. It is this type of advanced warning system that pump patients need as it would give them time to react and make the necessary adjustments.
As Diabetic Investor has stated previously we are not convinced there is a need for a true closed loop system however, we do believe the quest for such a system will eventually lead to better and more useful technology. The only problem is given the ultra-conservative nature of the FDA it’s anyone’s guess when or if this advanced technology will ever see the light of day. The bottom line is until the FDA changes and begins to understand that patients with diabetes need better tools to help them manage their diabetes more effectively not much will change.
