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Phase 2RecruitingNCT07187531

SAFEGUARD: SAB-142, a fully human anti-thymocyte globulin, in new-onset stage-3 T1D

The first properly powered test of SAB-142, an anti-thymocyte globulin made from human antibodies rather than rabbit ones. Low-dose rabbit ATG already preserves the body's own insulin production after diagnosis, but serum sickness and anti-drug antibodies make it a one-shot drug. A human version is meant to be re-dosable — so SAFEGUARD gives two courses six months apart and measures C-peptide at 12 months.

Primary endpoints

  • Part B: change from baseline in 2-hour mixed-meal-tolerance-test stimulated C-peptide AUC at 12 months
  • Part A: treatment-emergent adverse events, adverse events of special interest and serious adverse events through week 4

Results so far

No results posted. The trial started recruiting in November 2025; ClinicalTrials.gov lists primary completion in November 2027 and study completion in December 2028. SAB Biotherapeutics has guided to topline data in the second half of 2027 — that is company guidance, not a registry commitment.

The full picture

SAFEGUARD is the trial that decides whether SAB-142 is a real drug or a good idea. Anti-thymocyte globulin already works in newly diagnosed type 1 diabetes — a single low-dose course of the rabbit-derived version preserves the body's own insulin production for at least two years (our record on it) — but because it is a rabbit protein, the immune system learns it. Serum sickness and anti-drug antibodies make a second course impractical. SAB-142 is the same class of drug produced as human antibodies, and its entire promise is that you could give it more than once.

SAFEGUARD is the first trial designed to test that promise: two treatment courses, six months apart, in people who were diagnosed within the last 100 days.1

Design

The trial runs in two parts. Part A is an open-label dose-ranging stage in adults aged 15–40, comparing a high and a low dose of SAB-142 with no placebo arm; its primary measure is safety — treatment-emergent adverse events, adverse events of special interest and serious adverse events through week 4. Part B is the randomised, double-blind, placebo-controlled efficacy stage, and it widens the age range to 5–40.1

Participants must have stage 3 T1D diagnosed within 100 days of randomisation, at least one islet autoantibody, a random C-peptide of at least 0.2 nmol/L, and a weight of at least 16 kg. Anyone who has had teplizumab or another investigational anti-CD3, verapamil or baricitinib is excluded — so this is not a trial you can enter after trying the approved new-onset immunotherapy.1

Estimated enrollment is 159, across roughly 70 registered sites in the US, UK, Australia, New Zealand and eleven European countries. It has been recruiting since 25 November 2025.1

Endpoints and timing

The efficacy endpoint that matters is change from baseline in C-peptide AUC over a 2-hour mixed-meal tolerance test at 12 months (Part B) — the same currency teplizumab's trials trade in, and the reason results here will be directly comparable.1

Secondary endpoints reach past C-peptide into outcomes people actually feel: time in tight range (above 70 to 140 mg/dL, or above 3.9 to 7.8 mmol/L), time in range (above 70 to 180 mg/dL, or above 3.9 to 10.0 mmol/L), HbA1c, total exogenous insulin use, and partial-remission rates by IDAA1c of 9 or below.1

ClinicalTrials.gov lists estimated primary completion in November 2027 and study completion in December 2028. SAB Biotherapeutics has said it expects to share topline data in the second half of 2027; that is the company's guidance, not a registry commitment.2 No results have been posted.

What to watch for

Two things will tell you whether the thesis survives.

The first is the second course. Re-dosing is the whole argument for a human ATG, and SAFEGUARD is the first study to give one in T1D. If anti-drug antibodies or infusion reactions show up at month 6 the way they do with rabbit ATG, the advantage over a drug that already exists largely evaporates.

The second is the population. SAB-142's only human efficacy signal so far comes from four people with established T1D in a phase 1 — reported in press releases, not a peer-reviewed paper. SAFEGUARD is testing it in new-onset disease, where there is more insulin-producing tissue left to protect. Mechanistically that should help, but it remains an untested population for this specific drug, and a phase 2b with 159 participants is where optimistic small-sample signals usually get their first honest examination.

The sponsor calls SAFEGUARD "registrational".2 The registry simply calls it phase 2.1 Treat the gap between those two descriptions as the appropriate level of uncertainty.

References

  1. SAb Biotherapeutics. SAFEGUARD — A Phase 2b Study Evaluating the Efficacy and Safety of SAB-142 for Delaying the Progression of Type 1 Diabetes in Patients With Stage 3 New Onset of Type 1 Diabetes, NCT07187531. ClinicalTrials.gov (accessed 2026-07-14). https://clinicaltrials.gov/study/NCT07187531 ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7

  2. SAB BIO to Present Data on SAB-142 at the American Diabetes Association's 2026 Scientific Sessions and FOCIS 2026 Annual Meeting. SAB Biotherapeutics press release, 29 May 2026. https://www.globenewswire.com/news-release/2026/05/29/3303527/0/en/sab-bio-to-present-data-on-sab-142-at-the-american-diabetes-association-s-2026-scientific-sessions-and-focis-2026-annual-meeting.html ↩ ↩2