Accepted answer
SURMOUNT-4 would have written it into the protocol, and the wording is the part that matters. Escalation protocols in this class generally permit a delay at the current level, sometimes a single step down with a later re-attempt, and count a participant as remaining in the arm throughout. That is analytically important: an intention-to-treat analysis keeps them at their randomised assignment regardless of the dose they were actually taking, so the "top dose" arm contains people who never reached the top dose. Find the protocol amendment history as well as the paper, because tolerability rules are among the things most often revised mid-programme, and dose-escalation decisions are made under supervision — nothing here is medical advice.
The initiation step in most schedules is not intended to be therapeutic; it is there to introduce the receptor to the drug.
Holding a step for eight weeks instead of four is a legitimate approach with no efficacy cost at the destination, and it is what the trials effectively did for anyone who tolerated poorly.
Worth being precise here: for an agent with a one-week half-life, steady state after a dose change is reached in about four to five weeks. Escalating at two weeks means escalating from a position you have not yet reached, and the resulting exposure is higher than the schedule intends.
Four to five half-lives to steady state is standard first-order pharmacokinetics and gives the four-week interval directly from the one-week half-life.
Stepping back is a normal adjustment, not a failure.