Faculty Collaboration Database

SPECTREM phase IIIb clinical trial results through week 16: guselkumab efficacy and safety for the treatment of low body surface area, moderate psoriasis with high-impact site involvement. Br J Dermatol 2026 Jan 06;194(1):25-36

Date

08/28/2025

Pubmed ID

40875818

DOI

10.1093/bjd/ljaf327

Scopus ID

2-s2.0-105027988127 (requires institutional sign-in at Scopus site)   4 Citations

Abstract

BACKGROUND: Patients with psoriasis affecting a low percentage of their body surface area (BSA) are under-represented in clinical studies and may face substantial disease burden if high-impact sites are affected.

OBJECTIVES: To evaluate in a phase IIIb randomized placebo-controlled study (SPECTREM; NCT06039189) the efficacy and safety of guselkumab in participants with low BSA (2-15%), moderate [Investigator's Global Assessment (IGA) = 3] plaque psoriasis involving one or more high-impact site (scalp, face, genitals, intertriginous areas).

METHODS: Eligible participants were randomized 2 : 1 to receive guselkumab 100 mg or placebo at week 0 and week 4, then every 8 weeks. The primary endpoint was the proportion of participants achieving IGA 0/1 (cleared/minimal) at week 16. Major secondary endpoints included the proportion of participants achieving ≥ 90% improvement in Psoriasis Area and Severity Index (PASI 90), IGA 0 and 100% improvement in PASI (PASI 100); mean percentage improvements from baseline to week 16 in BSA and PASI; and proportions of participants achieving site-specific IGA or Physician's Global Assessment (PGA) 0/1 among those with scalp, facial, genital or intertriginous site-specific IGA/PGA ≥ 3 at baseline.

RESULTS: Among the 338 randomized participants (guselkumab, n = 225; placebo, n = 113), mean (SD) baseline BSA was 7.6% (3.7) and PASI was 9.0 (3.8). At week 16, all primary and major secondary endpoints were met, with guselkumab demonstrating superiority vs. placebo (all P < 0.001) in the proportions of participants achieving IGA 0/1 (74.2% vs. 12.4%), IGA 0 (40.4% vs. 3.5%), PASI 90 (52.9% vs. 6.2%) and PASI 100 (32.4% vs. 2.7%), and mean percentage improvement from baseline in BSA (80.6% vs. 6.1%) and PASI (82.6% vs. 13.7%). Site-specific IGA/PGA 0/1 response rates for guselkumab vs. placebo were as follows: scalp 75.0% (n = 114/152) vs. 14.5% (n = 11/76); face 87.8% (n = 79/90) vs. 28.6% (n = 12/42); genital 78.0% (n = 64/82) vs. 37.5% (n = 15/40) and intertriginous 86.5% (n = 96/111) vs. 28.8% (n = 15/52). In the guselkumab and placebo groups, respectively, 37.8% and 39.8% experienced one or more adverse event; no new safety signals were identified.

CONCLUSIONS: Through week 16, guselkumab was effective and well tolerated in participants with low BSA, moderate plaque psoriasis with involvement of high-impact sites. Statistically significant improvements across multiple clearance measures, irrespective of baseline BSA, support the effectiveness of guselkumab across a broad range of patients.

Author List

Stein Gold L, Gottlieb AB, Armstrong AW, Alkousakis T, Bissonnette R, Langley RG, Krueger J, Papp K, Choi O, Rowland K, Chan D, Jeyarajah J, Park-Wyllie L, Gao LL, Gordon KB, Merola JF, Lebwohl MG, Strober B

Author

Kenneth Brian Gordon MD Professor in the Dermatology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Aged
Antibodies, Monoclonal
Antibodies, Monoclonal, Humanized
Body Surface Area
Dermatologic Agents
Double-Blind Method
Female
Humans
Male
Middle Aged
Psoriasis
Severity of Illness Index
Treatment Outcome