Type 1 diabetes: how immunotherapy delays onset and reduces severity

With innovative drugs, it is possible to intervene on the mechanisms that generate the disease by overcoming the limitation of only managing the metabolic consequences

by Paolo Fiorina*

9 March 2026

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3' min read

Translated by AI

Versione italiana

3' min read

Translated by AI

Versione italiana

For decades, type 1 diabetes was considered an unavoidable condition: once the autoimmune process that destroys insulin-producing pancreatic beta cells was triggered, the only possible strategy was to replace the missing hormone and control the complications over time. Today, for the first time, this paradigm is changing.

New immunological therapies make it possible to intervene before the disease manifests itself, delaying its onset and reducing its severity. This is a major conceptual shift: from metabolic control to modulation of the autoimmunity that underlies the disease.

The diagnosis of type 1 diabetes

Type 1 diabetes is a chronic autoimmune disease in which the immune system progressively attacks the beta cells of the pancreas, leading to the loss of insulin production. The result is hyperglycaemia and the need for lifelong insulin therapy, with the risk of micro- and macrovascular complications in the long term. Unlike type 2 diabetes, it is not related to lifestyle but to an altered immune response, the mechanisms of which are not yet fully understood.

Although less frequent than type 2 diabetes - which affects about 5% of the population - type 1 diabetes is not marginal. In Italia, it affects around 0.2% of the population and the incidence is increasing, with an estimated growth rate of around 3% per year. The impact is particularly significant because it predominantly affects young people, with long-term clinical, social and economic implications.

The new monoclonal antibodies

The most significant new development is Teplizumab, a monoclonal antibody recently approved by the European Medicines Agency. The drug acts selectively on T lymphocytes involved in autoimmune aggression against pancreatic cells. In at-risk individuals - identifiable by the presence of specific autoantibodies and initial blood glucose changes - it is able to delay the onset of type 1 diabetes by about three years.

Three years may appear to be a limited interval, but in paediatric or adolescent age it represents a clinically and socially significant time. Moreover, when the disease does manifest, the onset is generally less severe, with a longer initial phase of partial residual pancreatic function and reduced insulin requirements. This is the first intervention capable of altering the natural history of the disease.

In Lombardy, the University of Milan and ASST Fatebenefratelli-Sacco were among the first centres authorised for compassionate use of the drug, in view of the pathway to reimbursability. This step highlights a central issue for the healthcare system: the ability to rapidly integrate therapeutic innovation into clinical practice, ensuring equity of access and sustainability.

Teplizumab is, however, only the beginning. Numerous other immunomodulating strategies are being studied: drugs directed against immune system costimulatory molecules, against pro-inflammatory cytokines, up to increasingly sophisticated cellular approaches. The goal is common: to selectively switch off autoimmunity, preserving beta-cell function as long as possible.

Current trials

Italian research also fits into this context. At the University of Milan, in collaboration with Boston Children's Hospital and the University of Padua, Immunostem, an experimental approach based on autologous stem cells, has been developed. The cells, harvested from the patient by apheresis, are modified using gene therapy techniques to acquire anti-inflammatory and immunoregulatory properties, then reinfused. Altheia Science biotech created on the basis of Paolo Fiorina's research is bringing Immunostem into the clinic with considerable economic investment.

The rationale is twofold: to target autoimmunity directed against insulin-producing cells and to avoid generalised immunosuppression by using the patient's own cells. Clinical trials are in the start-up phase. These studies are still preliminary, but the potential is significant: to maintain pancreatic function for longer, to prolong the 'honeymoon' phase after onset and, in perspective, to achieve regression of hyperglycaemia in a selected quota of patients.

Type 1 diabetes remains a complex challenge and there are no simple solutions. However, the entry of immunotherapy and gene therapy into this field marks a structural change: for the first time, we are not just managing the metabolic consequences of the disease, but intervening in the mechanisms that generate it.

For the healthcare system, this means rethinking early diagnosis paths, screening programmes in at-risk individuals, and care models that integrate therapeutic innovation and sustainability. For patients, it means opening up a new perspective: not just living with the disease, but changing its course.

It is a step that until a few years ago seemed unrealistic. Today it is a real possibility, based on scientific evidence and rapidly developing research.

*Lecturer in Endocrinology, University of Milan, Director Endocrinology and Diabetology Unit, ASST Fatebenefratelli-Sacco

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