Lilly registers phase 1 tirzepatide gastric emptying study in type 1 diabetes
An early Lilly study will measure how fast the stomach empties in adults with type 1 diabetes, a group tirzepatide is not approved to treat.
Eli Lilly has registered a phase 1 study of tirzepatide in adults who have type 1 diabetes, using oral acetaminophen to track how quickly the stomach empties. The record for NCT07803744 was first posted on September 4, 2026, and is listed as not yet recruiting [1].
The trial is described as a single-dose, blinded, randomized phase 1 study in adults with type 1 diabetes and overweight [1]. Gastric emptying will be measured with oral acetaminophen [1]. The registry entry does not list an enrollment target, the dose of tirzepatide, the number of study sites, or a start date [1].
Tirzepatide is sold under the brand names Mounjaro and Zepbound. It is not approved for type 1 diabetes [1], so the drug is not an FDA-approved treatment option for people with that condition, and use in that group would fall outside the approved label. The registry record does not say what Lilly hopes to learn from the gastric emptying data, whether the company plans a larger trial in type 1 diabetes, or what result would be considered meaningful [1].
The new phase 1 entry sits alongside a separate registry record for the ongoing SURPASS-T1D phase 3 program in type 1 diabetes [2]. Phase 1 is the earliest stage of testing in people, and this one is a single-dose study of a single measurement rather than a test of whether the drug controls blood sugar. It does not establish long-term safety in people with type 1 diabetes, and it does not test whether tirzepatide reduces the need for insulin in that population [1].
Why it matters for patients
Type 1 diabetes is not an approved use for tirzepatide [1], so there is no standard prescription route to the drug for that purpose today. This newly registered study does not change that, and because the record is listed as not yet recruiting, no one can enroll in it yet [1].
The measurement at the center of the study is gastric emptying, not blood sugar control, insulin use, or weight. The registry entry does not report how gastric emptying data in people with type 1 diabetes would be used, or how the results might relate to treatment decisions [1]. No results have been posted, so nothing in the record supports conclusions about whether tirzepatide is safe or effective for type 1 diabetes [1].
For adults with type 1 diabetes, the practical points are that tirzepatide remains unapproved for their condition [1] and that this is an early, single-dose study of a digestive measurement, not a trial of the drug as a treatment [1].
What happens next
The registry entry lists the study as not yet recruiting and does not include a start date, an estimated completion date, or posted results [1]. Lilly has not disclosed a timeline for when gastric emptying data would be available, and no readout date has been reported.
The two SURPASS-T1D phase 3 trials in type 1 diabetes are ongoing [2]. Their registry records do not include posted results, and no completion dates for them appear in the entries reviewed [2].
Sources
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