Oral Add-On Treatment for Type 1 Diabetes

Can an oral medicine be added to insulin for type 1 diabetes?

Type 1 diabetes is caused by autoimmune destruction of insulin-producing beta cells, which means people with the condition need lifelong insulin to survive. The clinical interest in oral add-on therapy comes from a persistent problem: even with modern insulin analogs, pumps and continuous glucose monitoring, many patients still face glucose variability, hypoglycemia risk, weight gain and difficulty reaching individualized glycemic targets.

In 2019, the European Medicines Agency's human medicines committee recommended extending dapagliflozin, an SGLT2 inhibitor, as an adjunct to insulin for certain adults with type 1 diabetes whose glucose control remained inadequate despite optimized insulin therapy. The recommendation was narrow, limited to patients with a body mass index of at least 27 kg/m2 and specialist supervision, reflecting that oral add-ons were never intended to replace insulin.

Why did ketoacidosis risk become the key safety concern?

SGLT2 inhibitors lower blood glucose by increasing urinary glucose excretion. That mechanism can reduce glucose levels, body weight and blood pressure, but in type 1 diabetes it can also mask a dangerous shift toward ketosis if insulin is reduced too far, food intake falls, illness occurs or dehydration develops. This is especially important because SGLT2-associated diabetic ketoacidosis can be euglycemic, meaning blood glucose may look less alarming than clinicians and patients expect.

EMA's original review noted a considerable increase in diabetic ketoacidosis risk despite risk-minimization measures. In 2021, dapagliflozin's type 1 diabetes indication was voluntarily withdrawn across Europe and the UK, and regulators advised that patients already using it for type 1 diabetes should discontinue under specialist guidance rather than stopping insulin or changing treatment alone.

What should patients take from this regulatory history?

The dapagliflozin experience illustrates why diabetes drug approvals depend on more than average HbA1c change. For people with type 1 diabetes, a therapy that modestly improves glucose control may still be unacceptable if it adds a hard-to-detect risk of ketoacidosis, especially outside closely monitored trial settings. Real-world safety depends on sick-day rules, ketone testing, insulin adjustment, hydration and rapid access to clinical advice.

Current diabetes standards continue to place insulin, glucose monitoring, education and individualized risk reduction at the center of type 1 diabetes care. People with type 1 diabetes should not start an SGLT2 inhibitor or any glucose-lowering add-on without an endocrinology plan that explicitly addresses ketone monitoring, illness management and when to seek urgent care.