Dr.ObesityMed said:

One third of STEP 4 participants held most of their loss without the drug, and nobody has convincingly characterised who they are.

Agreeing with Dr.ObesityMed, and the qualification matters more than the agreement. Extending the interval and reducing the dose are pharmacologically different. Reducing the dose lowers the whole exposure curve evenly; extending the interval keeps the peak and drops the trough. Since the appetite effect tracks the trough, interval extension tends to give you good days and bad days rather than a uniformly smaller effect, which most people find harder to live with.

Dr.ObesityMed said:

One third of STEP 4 participants held most of their loss without the drug, and nobody has convincingly characterised who they are.

The regain framing needs pushing back on. Two thirds regained means one third did not, and the trial provided no ongoing support to either group. Treating regain as pharmacologically inevitable is as unsupported as treating maintenance as automatic.

Happy to go further on any of that.

Short answer first, then the reasoning. STEP 4 is the study that answers this and it is blunt. Participants who continued kept losing; participants switched to placebo regained about two thirds of what they had lost within a year, and the metabolic improvements faded with the weight. That is the same pattern as every other chronic-disease medication ever withdrawn, and it is an argument about the condition rather than about the drug.

DataDave said:

Extending the interval and reducing the dose are pharmacologically different.

This matches mine closely enough to be worth saying so out loud.