Early Secukinumab Sustains Psoriasis Clearance a Year After Stopping

One in 5 adults with newly diagnosed moderate to severe plaque psoriasis maintained clear or almost-clear skin a full year after stopping secukinumab, according to 2-year results from the STEPIn trial (NCT03020199) published in the Journal of the American Academy of Dermatology.¹

Biologics Have Rarely Been Tested This Early in Psoriasis

Most biologic trial data in plaque psoriasis comes from patients who have lived with the disease for years. In the pivotal secukinumab trials ERASURE and FIXTURE, mean disease duration was about 17 years, and patients already carried 2 to 4 comorbidities at diagnosis. Nearly half of patients with moderate to severe psoriasis wait more than 3 years to start a systemic agent, leaving inflammation unchecked.

That delay carries its own cost. Psoriasis affects more than 8 million people in the US, nearly 60% of whom say it significantly disrupts daily life, and it raises the risk of cardiovascular disease, metabolic syndrome, and depression the longer it goes uncontrolled.² STEPIn was designed to test whether treating psoriasis this early could change its long-term course.¹

STEPIn's Withdrawal Design Tested Durability, Not Just Efficacy

The randomized, open-label, multicenter trial enrolled adults aged 18 to 50 across 44 sites with new-onset plaque psoriasis (first plaques within the previous 12 months) and moderate to severe disease (Psoriasis Area and Severity Index [PASI] score of 10 or higher; body surface area of 10% or more; Investigator's Global Assessment modified 2011 score of 3 or higher). All were naive to systemic treatment and phototherapy and received secukinumab, an interleukin-17A inhibitor, 300 mg subcutaneously, or narrow-band UVB, for 52 weeks.

Patients who achieved at least 50% PASI improvement at week 52 in either arm then stopped all study treatment and were followed, drug-free, through week 104. Of 77 patients randomized to secukinumab, 72 (93.5%) completed the treatment phase, vs 45 of 76 (59.2%) on narrow-band UVB. That dropout imbalance was steep enough that the researchers reported only secukinumab's off-treatment results, without a head-to-head comparison, to avoid a selection-bias distortion.

One in 5 Patients Stayed Clear a Year Off Treatment

At week 104, 20.8% of patients previously treated with secukinumab (n = 16 of 77) had sustained a PASI 90 response, and 22.1% (n = 17 of 77) had an Investigator's Global Assessment score of 0 or 1. Baseline median PASI was 15.6; it fell to a median of 0 through week 64 before rising to 3.0 by week 104. Among the 66 patients who entered drug-free follow-up at week 52, 44% (n = 29) never relapsed through week 104, and relapsers took a mean of 32 weeks to do so.

Quality-of-life gains partly held, too. Nearly 20% of patients (19.5%) reported little to no impact of psoriasis on daily life a year after their last dose, and patient-rated disease severity remained 33.6 points below baseline on a 100-point visual scale. A subgroup analysis hinted that timing within that first year still matters: patients diagnosed less than 6 months before enrollment numerically outperformed those diagnosed 6 to 12 months earlier on sustained PASI 90 (28.6% vs 14.3% at week 104), though the difference was not statistically significant.

Those numbers compare favorably with longer-standing disease. In ERASURE and FIXTURE, where patients averaged 17 years of psoriasis, 72.8% reached PASI 90 by week 52, versus 91.1% of STEPIn's new-onset patients, and only 20.8% stayed relapse-free a year after secukinumab withdrawal, compared with 44% in STEPIn. A companion mechanistic substudy offered a possible explanation: secukinumab normalized DNA methylation patterns in lesional skin to match non-lesional skin in new-onset patients, while a residual molecular scar persisted in longer-standing disease, evidence, the researchers said, that the durability reflects altered disease biology rather than lingering drug.

“These findings, together with the observation that IL-17 targeting biologics are more effective if used early in the disease course, support a change in the management of patients with moderate to severe plaque psoriasis towards proactive early intervention,” the researchers wrote.

An Open-Label Design Limits How Far the Findings Travel

The trial's central limitation is its lack of blinding, unavoidable when comparing a self-injected biologic against in-office phototherapy. The narrow-band UVB arm saw far higher dropout by week 52 (40.8%) than secukinumab (7.0%), leaving only phototherapy's strongest responders eligible for drug-free follow-up. That selection bias, the researchers said, made a direct efficacy comparison unreliable, and cross-trial comparisons with ERASURE and FIXTURE carry the usual caveats of differing populations and eras.

For clinicians and payers, the results reframe timing as a lever in its own right, not just a question of which drug to choose. Patients who start a high-efficacy biologic within the first year of diagnosis, well before the multiyear delays common in practice, may retain some benefit through planned interruptions such as surgery or pregnancy. Most patients who stopped secukinumab still lost their response, so the results argue for earlier initiation, not for treating psoriasis as curable once controlled.

References

1. Iversen L, Langley RG, Gudjonsson JE, et al. Impact of early treatment of psoriasis on disease recurrence—results from the STEPIn study. J Am Acad Dermatol. 2026;95(1):95-103. doi:10.1016/j.jaad.2026.03.050
2. Psoriasis statistics. National Psoriasis Foundation. Updated December 21, 2022. Accessed August 25, 2026. https://www.psoriasis.org/psoriasis-statistics/