Dulaglutide vs Semaglutide: Trial Results

The direct comparison

SUSTAIN 7 randomized 1,201 adults with type 2 diabetes inadequately controlled on metformin. It was an open-label trial: participants and investigators knew the assigned treatment. Its primary endpoint was change in HbA1c, and body-weight change was a confirmatory secondary endpoint, both measured at 40 weeks ^[1].

Semaglutide produced greater reductions in HbA1c and weight than dulaglutide in both tested comparisons. The between-group weight differences were approximately 2.26 kg and 3.55 kg. This supports a specific conclusion about the treatments, population and time point studied ^[1].

It does not establish that one molecule is better for every patient or every outcome. The trial did not use heart attacks, strokes or cardiovascular death as its primary comparison, and it was not a study of people without diabetes seeking obesity treatment.

What REWIND adds

REWIND asked a different question. It randomized 9,901 adults with type 2 diabetes and either previous cardiovascular disease or cardiovascular risk factors to dulaglutide or placebo. Its primary outcome combined nonfatal heart attack, nonfatal stroke and cardiovascular death, with median follow-up of 5.4 years ^[2].

The primary outcome occurred in 12.0 percent of the dulaglutide group and 13.4 percent of the placebo group. The hazard ratio was 0.88, with a 95 percent confidence interval of 0.79 to 0.99. All-cause mortality did not differ significantly ^[2].

That is evidence for a cardiovascular outcome against placebo in the studied population. It is not a head-to-head cardiovascular comparison with semaglutide. Using the weight ranking from SUSTAIN 7 to rank cardiovascular protection would combine questions the trials kept separate.

The later dulaglutide study

AWARD-11 randomized 1,842 adults with type 2 diabetes inadequately controlled on metformin and compared three dulaglutide treatment groups. It assessed HbA1c and weight changes, with the main efficacy comparisons at 36 weeks ^[3].

The highest-strength group achieved greater HbA1c and weight reductions than the lower-strength comparator. For weight, the treatment-regimen analysis reported reductions of 4.6 kg versus 3.0 kg. The study contained no semaglutide group ^[3].

These findings show why an older head-to-head comparison should not be treated as a test of every later option. They do not justify placing results from separate studies into a new ranking: populations, follow-up and analytic methods may differ.

Reading the outcomes side by side

The most useful comparison starts with the question being asked. Glucose control, weight change and cardiovascular events are related clinical concerns, but they are not interchangeable endpoints. A study can establish an effect on one without settling the others.

For a direct relative claim, look for both treatments in the same randomized study. For a claim about long-term events, look for those events as actual outcomes rather than an assumed consequence of a laboratory or weight change.

Tolerability and individual decisions

Gastrointestinal problems were common in SUSTAIN 7 and were the leading reason for discontinuation. REWIND also recorded more gastrointestinal adverse events with dulaglutide than placebo, and AWARD-11 reported nausea and vomiting across its groups ^{[1, 2, 3]}. Neither greater average weight loss nor a favorable cardiovascular result removes the need to consider tolerability.

The dulaglutide and semaglutide monographs contain their separately dated regulatory and safety records. These trial results support a discussion of treatment goals and evidence, not a dose conversion or an instruction to switch medicines.

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