Reviews/Psoriasis Psoriatic Arthritis/IL-23p19 inhibitors post-withdrawal durability
Pso Il23 · PSA-IL23-03 · v2
The claim says that after patients planned to stop an IL-23p19 inhibitor, most keep clear skin, with many still at a high level of clearance (PASI 90) six months later. The only study in this corpus that actually tested stopping treatment did the opposite of supporting this: when patients came off the drug, the share still at PASI 90 dropped sharply while those who stayed on treatment mostly held their response [1]. The trial's own summary states that most patients lost their response after stopping and regained it only when treatment was restarted [1]. The corpus does not report any figure at the exact six-month mark, and the nearest reported timepoint already shows response collapsing [1]. It also tested only one drug, guselkumab, in a single trial, so a claim about the whole class rests on a very narrow base [1][2].
The only planned-withdrawal evidence is the VOYAGE 2 trial, reported in [1] and [2]. In [1], patients rerandomised to withdrawal fell to PASI 90 of 11.5% versus 86.0% in the maintenance group by week 72, and the abstract states 'most patients lost clinical response' on withdrawal, regaining it after 20 weeks of retreatment (80.4% reaching PASI 90). In [2], the same trial reports better persistence in the maintenance group than the withdrawal group (P<.001). Every other corpus paper measures behaviour on continued treatment — drug survival [3][4][5][7], activity-guided dose reduction [6], and super-responder status [8] — none of which test planned withdrawal. The contested point: The corpus does not divide on the direction of the withdrawal effect: the direct data in [1] run against the claim. The only slack is timepoint indirectness — the reported figure is week 72, roughly ten months after withdrawal, while the claim specifies six months, which no corpus paper measures.
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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
The only on-claim primary data ([1]) show the withdrawal arm at PASI 90 11.5% vs 86.0% maintenance — this refutes 'a substantial proportion maintaining PASI 90' rather than supporting it.
The trial's own stated conclusion is that 'most patients lost clinical response' on withdrawal, directly opposing 'sustained clinical response following planned treatment withdrawal'.
Where it remains uncertain. The nearest reported timepoint is week 72, not the six-month mark the claim specifies, so the exact six-month proportion is unmeasured here [1].
Aleatory
A minority did retain response after withdrawal (11.5% at PASI 90) and retreatment recovered 80.4% [1], so individual outcomes after stopping vary rather than being uniform.
Epistemic
The corpus reports week 72 but no six-month post-withdrawal PASI 90, so the exact figure the claim specifies is unknown here [1].
Inferential
Generalising to 'IL-23p19 inhibitors' rests on inferring from a single molecule in a single trial [1][2].
The load-bearing papers from a corpus of 8, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
Directly contradicts 'substantial proportion maintaining PASI 90' after withdrawal — only 11.5% maintained.
“Upon guselkumab withdrawal, most patients lost clinical response and regained responses with retreatment.”
Panel auditInternal validity: high · scope of inference: Week-28 guselkumab PASI 90 responders with plaque psoriasis who are then withdrawn versus maintained, followed to week 72.Key limitations: exact timepoint of 11.5%/86.0% comparison not fully specified in abstract · no p value or CI reported for the contrast · single agent (guselkumab)
1 of 8 papers shown. The full review lists all of them, with the panel’s arbitration →
Claims are graded at each quarterly release, and re-graded between releases only when a pivotal trial lands. Every change is a new version of the claim.
The direct randomised-withdrawal data affirmatively contradict the claim (11.5% PASI 90), leaving only a low residual confidence tempered by the unmeasured exact 6-month timepoint.
Release 2026-q4 re-graded every claim from its corpus under protocol v0.19. An earlier release's grade is shown for the record; it came from an earlier protocol and is not a movement.
Assumptions that carry weight but are not themselves established.
The panel records the gap that would most move the claim, and the study that would close it.
Six-month post-withdrawal PASI 90 figure. The claim specifies a six-month proportion the corpus never reports; the only figure is at week 72 [1]. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: A withdrawal trial reporting PASI 90 maintenance at a prespecified six-month timepoint after the last dose.
Open question: What proportion of patients maintain PASI 90 exactly six months after planned withdrawal of an IL-23p19 inhibitor? Why it is still open: The corpus reports only week 72 (~10 months), never the six-month timepoint the claim names [1].
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 18 Sep 2026 · protocol v0.19