Closed-Loop Insulin Delivery: The Algorithm Is the Easy Part

Somewhere inside Insulet right now, a product team has agreed to delete a button. The meal-announcement button, the one a person with diabetes presses to tell their pump a meal is coming, is on its way out. Insulet, MiniMed, and Tandem are all chasing the same finish line: an insulin system that doses correctly without ever being told to expect food. The trade press is calling it the arrival of the fully closed loop, and the algorithm gets all the attention. It is the easy part. Deleting that button is a regulatory and validation decision in a UX costume, and the company that understands that is the one that finishes.

The Button They Are Deleting

Here is the state of the race, per MedTech Dive. Insulet started a pivotal study in May for an automated insulin delivery system with no meal announcements, scoped to people with Type 2 diabetes who take insulin, with a 510(k) submission planned for 2027 and a launch targeted for 2028. MiniMed is studying a system called Vivera, where the meal announcement becomes optional rather than gone, in both Type 1 and Type 2 patients, and running a lower insulin target than its current 780G system. Tandem says it will start its own pivotal trial later this year. Three companies, three different answers to the same product question: how much of the human do you design out, and for whom?

The trade-offs are the whole story. Take away the meal announcement and the algorithm now has to detect the meal and deliver the right dose on its own, without tipping a patient into hypoglycemia. Even the systems chasing a fully closed loop are not hands-off: users still adjust for exercise and illness, a sensor failure drops the device into a backup mode that asks for manual input, and performance shifts with the meal, the type of carbohydrate, and the size of the plate. None of that is a problem you solve in the algorithm once. It is a validation burden you carry through every one of those conditions, in front of the FDA, before you are allowed to ship.

Watch where the population lines fall, because that is the real decision. When I was at Galen, we learned the expensive way that your study population is itself a regulatory claim, not a recruiting detail. We told the FDA we would run our cadaver study with surgical residents, got a written yes in the pre-submission, then watched the substantive review reopen it: were we planning to market to residents? We re-ran the entire study with sixteen attending surgeons in two weeks to keep the claim clean. Insulet scoping its first closed-loop system to Type 2 insulin users is that same lesson applied early and on purpose. A narrower population is a smaller, more defensible thing to prove. MiniMed studying both Type 1 and Type 2 is making a broader claim, and broader claims cost more to validate.

Who Owns the Sensor

Two days before that race got fresh coverage, MiniMed answered a different product question, and it is the one founders tend to underrate. On June 3 it expanded its partnership with Abbott to put a dual glucose-ketone sensor on its dosing systems, a sensor that watches for rising ketones to catch diabetic ketoacidosis before it becomes an emergency, per MiniMed. The sensor is built by Abbott, matches the size of the Instinct sensor the two companies already ship together, and is designed to plug exclusively into MiniMed's systems. Abbott holds a CE mark in Europe; the dual sensor is still under FDA review and not yet sold in the United States.

In a closed-loop system, the sensor is not a component. It is the safety system. Everything the algorithm decides rests on whether the number coming off that sensor is true. MiniMed, a standalone diabetes company, has chosen to rent that input from Abbott, a company that sells sensing technology of its own. There are good reasons to do it: Abbott makes one of the smallest, most refined sensors in the world, and standing up a rival in-house would cost years MiniMed may not have. But it is a product-architecture decision dressed as a supply agreement, and it sets who controls the validation, the roadmap, and the failure modes of the one part the whole system has to trust. Adding a second analyte, ketones, widens what the system claims to do and widens what has to be validated next to it. The question worth pushing on is not the price of the sensor. It is what happens to the product the day the supplier's roadmap and yours stop pointing the same way.

Dave Saunders is the founder of Base Reality Group and a Fractional CPO for hard-tech founders. He was a founder and operator at Galen Robotics, where the surgical-robotics platform earned FDA De Novo authorization in 2023, and he managed a 35-patent portfolio licensed from Johns Hopkins. He wrote Founders Who Finish and publishes The Build. More about Dave →