Journal club: STEP 8 and the fairness of the comparator dose

Journal club: STEP 8 and the fairness of the comparator dose — setting out what I have, and where I think it stops being reliable.

Comparing SURMOUNT-2 (Lancet, 2023) with STEP 8 (JAMA, 2022) and finding the comparison harder than it looks.

Different populations, different durations, different endpoints defined slightly differently, and in one case a different estimand. People compare the headline percentages anyway, including me until recently.

Is there a defensible way to put these side by side, or is the honest answer that there is not and we should stop?

This follows the opening post rather than contradicting it.

STEP 1 (N Engl J Med 2021): The pivotal obesity trial for semaglutide and the reference point for most subsequent comparison. Mean weight reduction was substantially larger than anything previously achieved pharmacologically.

SELECT (N Engl J Med 2023): Semaglutide cardiovascular outcomes without diabetes. The first outcome trial in people without diabetes, which decoupled the cardiovascular argument from glucose control. Read the absolute numbers, not just the relative reduction.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

Coming back to post #3, because the follow-up matters more than the original answer.

SOUL (N Engl J Med 2025): Oral semaglutide cardiovascular outcomes. Extends the cardiovascular evidence to the oral formulation. Note that oral bioavailability is lower and more variable than injectable.

TRIUMPH (ongoing): Retatrutide phase 3. No results yet. Nothing should be attributed to it because it has not finished. When it does, this discussion will return to it.

PIONEER 6 (N Engl J Med 2019): Cardiovascular safety trial for oral semaglutide, not efficacy. Non-inferiority for safety was met. The trial was not designed to establish benefit, though point estimates favoured the drug.