Today is a landmark day for type 1 diabetes. The FDA has approved an expanded indication for Tzield (teplizumab-mzwv) to delay the onset of stage 3 type 1 diabetes in children as young as one year old.

This is a big deal. Let us explain why.

What Is Tzield?

Tzield is the world's first disease-modifying therapy for type 1 diabetes. Rather than managing blood sugar after diagnosis, Tzield works before the disease becomes insulin-dependent — targeting the immune cells that attack the pancreas.

When the FDA first approved Tzield in 2022, it was for people age 8 and older who had been diagnosed with stage 2 T1D (meaning the autoimmune attack had begun, but insulin production hadn't yet failed). Clinical trial data showed it could delay the onset of stage 3 T1D — the point at which insulin therapy is required — by a median of three years.

Today's expansion brings that protection to children as young as one year old.

What Is Stage 2 T1D?

Type 1 diabetes progresses in stages:

Stage 1: Two or more T1D-related antibodies detected in the blood. Blood sugar is normal.
Stage 2: Blood sugar is beginning to go out of range. Symptoms may not be obvious.
Stage 3: Blood sugar is high enough to cause symptoms. This is the point of formal diagnosis for most families.

Most families only discover T1D at stage 3 — often in a medical crisis. But if a child has a family member with T1D, screening can catch it earlier, while there's still a window to intervene.

The PETITE-T1D Study

Today's approval was supported by data from the PETITE-T1D phase 4 study. In an interim analysis, most young children receiving Tzield did not progress to stage 3 type 1 diabetes.

For families of very young children who have tested positive for T1D-related antibodies, this is potentially transformative news.

What Should Families Do?

If your child has been diagnosed with T1D — or if you have a family history and want to screen a sibling or other child — talk to your endocrinologist or pediatrician about whether T1D antibody screening makes sense. And if a family member has stage 2 T1D, ask specifically about Tzield and whether it might be appropriate.

The disease is not standing still. Neither is the medicine.

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