AT278 (U500 ultra-rapid insulin aspart)
Arecor Therapeutics
What it is
An investigational ultra-concentrated (500 U/mL), ultra-rapid mealtime insulin aspart from Arecor. In a Phase 1 type 1 diabetes clamp study it was absorbed faster than standard aspart despite being five times more concentrated, pointing to lower injection volumes for people with high insulin needs. Reported findings are from a single-dose study in 38 men with type 1 diabetes.
Editorial review: .
Most recent recorded citation date: 2026-07-30. Only explicit date metadata is included; an undated citation may be newer. This does not mean every claim was reviewed on that date.
Trial status, labels and access can change between reviews. How we review the evidence · How to read the evidence
Evidence behind this assessment
Key evidence notes. Study results, product eligibility and access answer different questions.
- Who was studied?
- Study populations and analysis groups vary. Product age limits alone do not describe who was studied.
- Benefit or performance
- Consistency: Only single-dose Phase 1 clamp data exist in a small all-male T1D cohort; day-to-day and real-world absorption variability is unproven, especially at 500 U/mL.[1]
- Important harms and treatment burden
- Read the safety discussion and original sources. A missing summary does not establish safety.
- Approval and country access
- Country-specific approval and access are not summarized in this record.Approval, trial recruitment, local supply and funding are separate. Check the cited label or access source.
- Follow-up and remaining uncertainty
- Read the full discussion and original sources for follow-up duration and study limitations.
Research status alone does not establish approval, clinical benefit or local availability. This record cites company or conference reports. Those sources may describe interim findings; their source type is shown in the source list.
Editorial score: calculation and evidence
A weighted editorial judgment on a 0–100 scale, not a probability of success or a measured treatment effect. Higher criterion scores mean more favorable assessments.
Default calculation: 80 × 20 + 78 × 25 + 60 × 15 + 50 × 20 + 50 × 10 + 10 × 10 = 6050; divide by total weight 100. Unrounded weighted result: 60.5.
Mealtime convention (faster onset is better): in T1D, onset of glucose-lowering action was 10 min earlier than standard aspart and serum appearance 6 min earlier; faster than today's analogs but no head-to-head vs Fiasp.[1]
Mealtime convention (faster/earlier exposure is better): 4.0-fold higher insulin exposure in the first 30 min and 8.9-fold higher early glucose-lowering effect vs aspart, so action is front-loaded — though still far from the sub-20-min ideal.[1]
Mealtime convention (shorter tail is better): front-loaded exposure implies a relatively shorter tail, but the clamp study did not report a clear duration advantage, so this is scored conservatively. Assessment is editorial on this page, drawn from the cited clamp report.[1]
Only single-dose Phase 1 clamp data exist in a small all-male T1D cohort; day-to-day and real-world absorption variability is unproven, especially at 500 U/mL.[1]
A faster, shorter-acting bolus could in principle reduce residual insulin during activity, but no exercise or hypoglycemia-flexibility data are available; scored neutral. Editorial assessment on this page; no source claim beyond the cited clamp study.[1]
Access convention (cheaper/more available is better): not approved anywhere, no price, no marketed product — effectively inaccessible today.[2]
Insulins are scored relative to their role peers (see tags: rapid, ultra-rapid, basal, inhaled). A basal insulin's onset score compares it to other basals, not to mealtime insulins.
The full picture
AT278 is an investigational mealtime (bolus) insulin from Arecor, built on its Arestat formulation technology. It is unusual in two ways at once: it is ultra-concentrated at 500 U/mL — five times the strength of standard insulin aspart — yet engineered to be absorbed faster, not slower. Normally, concentrating insulin slows absorption, so combining high strength with rapid onset is the technical achievement. Product characterisation follows Arecor; clinical findings in the next paragraph are from the single-dose Phase 1 type 1 diabetes clamp study by Svehlikova and colleagues (Diabetes Care 2023) cited on this page.
The key evidence comes from a Phase 1, double-blind, randomized crossover clamp study in 38 men with type 1 diabetes, comparing a single dose of AT278 against standard insulin aspart. AT278 reached the bloodstream about 6 minutes earlier and began lowering glucose about 10 minutes earlier. Early exposure was 4.0-fold higher in the first 30 minutes, and the early glucose-lowering effect was 8.9-fold higher in the first 30 minutes — a strongly front-loaded profile that more closely mimics a meal-time insulin burst.
The practical promise is twofold: faster post-meal coverage, and a much smaller injection volume for people with high insulin requirements, including pump users. The limitations are real — only single-dose Phase 1 data exist, in a small all-male cohort, and no Phase 2 trial is yet registered on ClinicalTrials.gov. The single-dose scope here reflects the type 1 diabetes clamp study; a separate 2026 type 2 diabetes pharmacology paper cited on this page does not establish type 1 closed-loop outcomes.
But AT278 is no longer an orphan asset. In September 2025 Arecor signed a co-development agreement with the US pump maker Sequel Med Tech, each company committing up to $1.3 million to the work needed to pair AT278 with Sequel's twiist automated insulin delivery system — FDA interactions, clinical trial batch manufacturing, and pump-compatibility testing. As of April 2026 Arecor reports positive feedback from a Type C meeting with the FDA on its Phase 2 study design, says it is targeting a Phase 2 start in the second half of 2026, and is negotiating a broader co-development and commercialisation deal.
Be precise about what that does and does not mean. Positive Type C feedback is not an approval and not an IND clearance — as of the April 2026 update the IND had not yet been filed. The planned study is a roughly six-week crossover against NovoLog in fewer than 100 people with high daily insulin requirements, and it is designed to enrol both type 1 and type 2 diabetes, so it is not a T1D-only trial. A concentrated, ultra-rapid insulin built specifically to run inside a closed loop is close to what the insulin-speed problem actually calls for — but it still has to survive a Phase 2 that has not started. Trial scope and filing status above follow the April 2026 company update cited on this page.
Additional 2026 evidence. A paper published online 30 July 2026 reports faster early absorption and greater first-hour glucose-lowering with AT278 U500 versus standard aspart U100 and regular human insulin U500 in type 2 diabetes. This supports concentrated-insulin pharmacology; it does not establish T1D AID effectiveness or superiority over Fiasp or Lyumjev.6
Coming soon
ETA · Phase 1 complete in type 1 diabetes (2023). Arecor signed a co-development agreement with pump maker Sequel Med Tech in September 2025 to combine AT278 with the twiist automated insulin delivery system, and reports positive FDA feedback on the Phase 2 design. It is targeting a Phase 2 start in 2H 2026 and negotiating a broader co-development and commercialisation partnership. No Phase 2 trial is registered on ClinicalTrials.gov as of 27 August 2026, and there is no approval anywhere.
- →Phase 2 targeted for 2H 2026, pairing AT278 with Sequel Med Tech's twiist automated insulin delivery system — not yet registered on ClinicalTrials.gov. Company target per 2026 updates; registration status as of 27 August 2026.
- →Broader co-development and commercialisation partnership under negotiation as of April 2026
- →If developed, the 500 U/mL strength would cut injection volume ~5-fold for people on large doses or in pumps. Arithmetic from 500 U per mL versus U100; clinical benefit unproven.
Sources
- [1]
- [2]
- [3]Arecor announces publication of Phase 1 data for AT278 in Diabetes Care · Science journalism · 2023-01-30
- [4]Arecor announces Co-development Agreement with US Insulin Pump Device Company (Sequel Med Tech) for AT278 · Manufacturer · 2025-09-25 — Each company commits up to $1.3M to Phase 2 trial-enabling activities (FDA interactions, clinical trial manufacturing, twiist compatibility). An IND filing is anticipated on completion, with a Phase 2 possible in 2H 2026.
- [5]Arecor targets broader AT278 partnership as phase II trial nears · Science journalism · 2026-04-13 — Reiterates positive feedback from a September 2025 Type C meeting with the FDA on the Phase 2 study design. This is neither an approval nor IND clearance.
- [6]AT278 U500 pharmacology in T2D acrossBMI · Peer-reviewed study · 2026-07-30 — Online publication30 July 2026;October 2026 issue. T2D pharmacology, not T1D AID outcomes; comparators were standard aspart U100 and regular human insulin U500.
Svehlikova etal. Diabetes,Obesity&Metabolism.