Reviews/Psoriasis Psoriatic Arthritis/Guselkumab 2-year PASI 90 durability
Pso Il23 · PSA-IL23-02 · v2
The evidence asks a narrow question: do patients who stay on guselkumab keep clear or nearly clear skin at the two-year mark? Two studies measure exactly two years and find about three-quarters to four-fifths of patients still at the high PASI 90 response level (a national registry [7] and a real-world clinic cohort [6]). The main clinical trial adds a very similar figure just under two years [1], and its sister trial shows the response holding across the whole period [2]. Several everyday-practice studies point the same way at three years and beyond [4][5]. The one caution is that the real-world figures count only patients still taking the drug, which can make the numbers look a little better than they would for everyone who started; the panel judged this shades the top figures without changing the overall picture.
Two datasets land on the exact 24-month timepoint: the BIOREP registry reports PASI 90 of 75.4% at 24 months [7], and a 104-week real-world cohort reports 79.63% after 2 years [6]. The pivotal RCT extension reports PASI 90 of 79.1% at week 100 [1], and VOYAGE 1 reports week 52 rates of 79.7%, 75.5%, and 80.6% by TFR, NRI, and OBS with maintenance through week 204 [2]. Additional real-world cohorts corroborate maintenance beyond the window, with 77.4% at week 144 [4] and 82.9% at 148 weeks [5]. The reported figures cluster consistently in roughly the 75-84% range across independent trial and real-world sources. The contested point: The division is over how much the real-world figures should count: [4], [5], and [6] measure only patients still on treatment, so response among retained patients is not the same as maintenance across everyone who began. [5]'s 82.9% is conditioned on the 96% still on treatment after 2 years, and [6] notes 91.57% of the cohort remained on guselkumab at 24 months.
All 8 papers behind this claim with their DOIs and what each does to it, the panel’s arbitration, the evidence gap map and the open research questions. Free, and sent to your inbox.
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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
Real-world PASI 90 rates in [4], [5], and [6] are observed-case among patients still on treatment, so survivor bias inflates them relative to an intent-to-treat estimate; [5]'s 82.9% is conditioned on the ~96% retained at 2 years.
The pivotal RCT [1] proxies 2 years with week 100 (~1.9 years) rather than an exact 24-month endpoint, a minor temporal indirectness.
Where it remains uncertain. Real-world rates count only retained patients, so figures such as 82.9% [5] and 79.63% [6] reflect responders still on drug rather than an intent-to-treat estimate.
Aleatory
Several real-world estimates come from single-centre retrospective cohorts [4][6], where limited sample size adds sampling variability to the point estimates.
Epistemic
The corpus reports observed-case real-world rates [5][6] and RCT extension figures but no clean ITT estimate of two-year PASI 90 across all starters.
Inferential
Treating the RCT's week-100 value [1] as the two-year datapoint infers a 24-month rate from a ~1.9-year measurement.
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.
Phase 3 RCT extension shows PASI 90 maintained at ~2 years (week 100 = 79.1%) under continuous dosing.
“The proportions of guselkumab-treated patients who achieved and maintained clinical responses at weeks 100 and 204, respectively, were PASI 90: 79.1% and 79.7%”
Panel auditInternal validity: medium · scope of inference: Continuously guselkumab-treated moderate-to-severe psoriasis patients in VOYAGE 2 over 100–204 weeks.Key limitations: no sample size · imputation method not stated · week 100 is ~23 months, not exactly 104 weeks
VOYAGE 1 RCT extension confirms sustained PASI 90 across analysis methods bracketing the 2-year window.
“At week 204, PASI 90 response rates were 82.2%, 68.4%, and 84.3%, respectively, based on TFR, NRI, and OBS analyses; corresponding proportions at week 52 were 79.7%, 75.5%, and 80.6%”
Panel auditInternal validity: medium · scope of inference: Continuously guselkumab-treated moderate-to-severe psoriasis patients in VOYAGE 1 over 52–204 weeks.Key limitations: no 2-year datapoint reported · no sample size · wide spread between NRI and OBS at week 204 (68.4% vs 84.3%)
Real-world cohort corroborates high PASI 90 maintenance around and beyond 2 years.
“97.6%, 82.9%, and 63.4% of patients respectively achieved PASI 75, 90, and 100 after 148 weeks. Overall, 96% of patients were on treatment after 2 years.”
Panel auditInternal validity: low · scope of inference: Real-world moderate-to-severe plaque psoriasis patients on guselkumab up to 148 weeks.Key limitations: PASI 90 reported only at 148 weeks not at 2 years · no sample size · observational design
PASI 90 of 84.1% and 82.0% at week 252 shows response sustained through 5 years, so the 2-year window within it is maintained by inference.
Panel auditInternal validity: medium · scope of inference: Continuously guselkumab-treated moderate-to-severe psoriasis patients in VOYAGE 1 and 2 through 5 years.Key limitations: reports only week 252, not 2 years · no sample size · no imputation method stated
4 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.
Independent RCT and registry datasets directly evidence sustained PASI 90 at 2 years under continuous dosing, with only survivor-bias tempering that does not threaten the direction or range.
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.
No intent-to-treat two-year rate. Every real-world figure counts only patients still on drug [5][6], leaving the whole-cohort two-year response unquantified. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: Report NRI or full intent-to-treat PASI 90 at exactly 24 months in a prospective cohort, counting discontinuations as non-responders.
Open question: What is the intent-to-treat PASI 90 rate at exactly 24 months, counting discontinuations as non-responders? Why it is still open: The corpus reports observed-case rates among retained patients [5][6] and RCT extension figures, but no ITT two-year estimate.
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 18 Sep 2026 · protocol v0.19