Netherlands Tests Dual-Hormone Closed Loop for Type 1 Diabetes

A study from the Netherlands is investigating one of the most ambitious advances in type 1 diabetes (T1D) management to date: a fully closed-loop system that automatically delivers both insulin and glucagon — the two hormones your pancreas normally uses to keep blood sugar balanced.

What Is a Dual Hormone Closed Loop System?

Most Americans with T1D who use automated insulin delivery (AID) systems — sometimes called "artificial pancreas" devices — rely on systems that deliver only insulin. These are known as hybrid closed-loop (HCL) systems, and they still require some user input, such as announcing meals.

The Dutch DARE trial takes this a significant step further. Their Dual Hormone Fully Closed Loop (DHFCL) system pairs continuous glucose monitoring (CGM) with an algorithm that automatically controls both insulin (to lower blood sugar) and glucagon (to raise it when needed). The goal: nearly zero manual intervention from the patient.

When blood glucose drops toward a low threshold — roughly under 70 mg/dL (3.9 mmol/L) — the system can release a small dose of glucagon to prevent hypoglycemia, rather than simply shutting off insulin and hoping for the best. The target range for most people with T1D, per American Diabetes Association (ADA) guidelines, is 70–180 mg/dL (3.9–10.0 mmol/L).

About the DARE Trial

Researchers at UMC Utrecht are enrolling 240 adults with type 1 diabetes across 14 hospitals in the Netherlands. Participants are randomly assigned either to the DHFCL system or to continue their current standard care — which may include a hybrid closed-loop device or multiple daily insulin injections combined with CGM or flash glucose monitoring (FGM).

The trial runs for 12 months, making it one of the longer evaluations of this technology to date. Researchers will measure:

• Glycemic control — including time in range (70–180 mg/dL) and A1C levels
• Quality of life — using patient-reported outcome surveys
• Cost-effectiveness — critical for understanding real-world adoption potential

Why This Matters for US Patients

The United States already leads the world in approved AID systems, with devices like Tandem Control-IQ, Omnipod 5, and Medtronic's MiniMed 780G available to patients. However, no dual-hormone fully closed-loop system is currently FDA-approved for routine use in the US.

This Dutch trial is significant for several reasons:

• It addresses one of the biggest remaining challenges in T1D management: hypoglycemia prevention without patient intervention
• A 12-month duration provides far more real-world data than most previous small studies
• Including cost-effectiveness analysis is essential for eventual insurance coverage decisions — a major concern for US patients
• Results from European trials often accelerate FDA review timelines for similar technologies

If the DARE trial confirms that dual-hormone systems outperform current hybrid closed-loop therapy over the long term, it could strengthen the case for US manufacturers and the FDA to fast-track comparable devices. American patients — particularly those who struggle with frequent hypoglycemia or hypoglycemia unawareness — stand to benefit most.

The Bottom Line

The DARE study from the Netherlands represents a carefully designed, large-scale test of technology that could redefine what "fully automated" diabetes management really means. US patients with T1D should watch for results, expected to be published in peer-reviewed journals and presented at international conferences.

Source: Jancev, Snoek, Frederix et al. "Dual hormone fully closed loop in type 1 diabetes: a randomised trial in the Netherlands — study protocol." BMJ Open, 2023. PMID: 37612114. DOI: 10.1136/bmjopen-2023-074984. ClinicalTrials.gov: NCT05669547.