The headline trial: SURPASS-2
SURPASS-2 (Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes)
Frias et al., New England Journal of Medicine, August 2021
Tirzepatide lowered HbA1c by about 2.0 to 2.3 percent across its 5, 10 and 15 mg doses versus 1.9 percent for semaglutide 1 mg over 40 weeks, and produced more weight loss (roughly 8 to 11 kg versus about 6 kg). Both semaglutide and tirzepatide are FDA-labeled for blood-sugar control in type 2 diabetes; in this head-to-head trial tirzepatide was superior on both A1c and weight.
Trial enrollment criteria
- Adults with type 2 diabetes on metformin, HbA1c 7.0 to 10.5 percent
- BMI 25 or greater
- Stable metformin dose for at least 3 months before screening
Does this trial apply to you?
Type 2 diabetes is the original FDA-labeled indication for every major GLP-1 and GLP-1/GIP drug. If your A1c is above target on metformin, semaglutide (Ozempic) and tirzepatide (Mounjaro) are both first-line add-on options under American Diabetes Association guidance. The diabetes indication is also the cleanest prior-authorization path in the whole category: coverage for type 2 diabetes is far broader than coverage for obesity alone.
What to ask your prescriber
- Most recent HbA1c, fasting glucose and any time-in-range data from a CGM
- Whether semaglutide or tirzepatide fits your weight, heart and kidney profile better
- Whether the diabetes indication (E11.x) is a cleaner PA path for you than the obesity indication
- Any personal or family history of medullary thyroid carcinoma or MEN2, which is a contraindication
Editorial notes
- If you also have kidney disease, heart disease, sleep apnea or fatty liver disease, the condition pages below carry the organ-protection trial evidence that strengthens both your treatment plan and your PA letter.
- If you take insulin or a sulfonylurea, your prescriber usually lowers those doses when you start a GLP-1 to avoid hypoglycemia.
- Oral semaglutide (Rybelsus) is an option for patients who prefer not to inject, though the once-weekly injections reach higher drug levels.
Clinical trials for Type 2 diabetes
Or browse the full GLP-1 clinical trials directory, filterable by condition, state and phase.
Take it to your prescriber: PA letter templates
Editable prior-authorization letter templates that cite the registration trial above. Pick the plan your prescriber will submit to, copy the template, fill in the patient-specific findings and have your clinician sign and submit.
Not seeing your plan? The full PA letter librarycovers 20 plans × 10 indications = 200 templates. The appeal letter library handles denials.
Drug profiles
Other GLP-1 conditions
Editorial provenance
Editorial review by John, Editor on 2026-05-23, against SURPASS-2 (Frias et al., New England Journal of Medicine, August 2021). We do not yet have a credentialed medical reviewer on staff (actively recruiting). This page summarises public registration-trial data and FDA labeling. It is not clinician-authored medical advice.
Disclaimer
Educational summary of published registration trial data. Not medical advice. Not a substitute for evaluation by a treating clinician. Trial-level results do not guarantee individual outcomes. Discuss eligibility, contraindications, dose adjustments and drug interactions with your prescriber. We do not have a credentialed medical reviewer on staff yet (actively recruiting); the content below is editor-written from public registration-trial publications and FDA labeling, not clinician-authored medical advice.