SURPASS J-combo
Safety and efficacy of tirzepatide as an add-on to single oral antihyperglycaemic medication in patients with type 2 diabetes in Japan (SURPASS J-combo): a multicentre, randomised, open-label, parallel-group, phase 3 trial.
Kadowaki T et al. · The Lancet Diabetes & Endocrinology
Study record
- Population
443 Japanese adults with type 2 diabetes receiving a single oral antihyperglycemic medication. The six background groups were biguanides, alpha-glucosidase inhibitors, thiazolidinediones, glinides, sulfonylureas and SGLT2 inhibitors. Complete eligibility reconciliation against the main report remains pending.
Inspect extraction gap · Supplementary materialTables S1-S12; Figure S1- Formulation
Tirzepatide administered using single-use pens.
Read source · Supplementary materialFigure S1 caption, p23- Route
Once-weekly subcutaneous administration.
Read source · Supplementary materialFigure S1 caption, p23- Dose & frequency
All participants started at 2.5 mg weekly, increasing by 2.5 mg every four weeks to their assigned 5, 10 or 15 mg dose. Background oral medication was maintained unless reduced for hypoglycemia. This describes the trial, not an individualized regimen.
Read source · Supplementary materialFigure S1 caption p23; Tables S7-S12 footnotes- Study design
Open-label phase 3 trial. Participants were randomized 1:1:1 among tirzepatide doses within their existing oral-medication group. No placebo or non-tirzepatide arm; background medications were not randomized.
Read source · Supplementary materialFigure S1; appendix cover- Duration
52 weeks of treatment followed by four weeks of safety follow-up, after a four-week screening and lead-in period.
Read source · Supplementary materialFigure S1 caption p23- Reported findings
At 52 weeks, adjusted HbA1c changes were −2.57, −2.98 and −3.02 percentage points and weight changes were −3.8, −7.5 and −10.2 kg for 5, 10 and 15 mg. These during-treatment efficacy estimates have outcome-specific denominators: HbA1c 137/134/125 and weight 137/135/125. They are within-group changes, not effects versus untreated patients.
Read source · Supplementary materialTable S18 pp21-22 and analysis footnotes- Adverse events
Summing the six background groups gives 109/148, 109/147 and 125/148 participants with treatment-emergent adverse events for 5, 10 and 15 mg. Adverse events led 8/148, 8/147 and 17/148 to stop the drug; fewer left the study. Documented glucose below 54 mg/dL occurred in 1/148, 1/147 and 3/148, despite no severe hypoglycemia in these tables. Categories overlap.
Read source · Supplementary materialTables S7-S12 pp8-13; totals calculated across distinct background groups- Monitoring
The protocol specifies site physician review of ECGs, blood pressure and heart rate, laboratory tests, and anti-tirzepatide antibody sampling. Clinically significant post-dose ECG, vital-sign or laboratory findings resulting in a diagnosis were to be recorded as adverse events. Central cardiologist ECG overreading was optional, not guaranteed. These are planned trial assessments, not a personal monitoring schedule.
Read source · Study protocolSection 9.4.1–9.4.4, printed pp49–50
What it supports
Describes 52-week glycemic, weight and safety findings when tirzepatide was added to an existing single oral diabetes medication in Japanese adults.
What it does not establish
The oral-medication backgrounds were not randomized, so comparisons across them cannot establish the best pairing. All groups received tirzepatide. Protocol eligibility and planned safety assessments have been inspected; this does not verify that every planned assessment was performed. Full report access remains limited. Supplement S11 prints 4 (3.0%) under N=129 for glucose below 54 mg/dL; the count and denominator do not reproduce that percentage, so no corrected percentage is substituted.
Funding
Eli Lilly and Company (primary abstract). Full sponsor role not yet verified.
Literature search cutoff: 2026-09-08 · Not independently clinically reviewed
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