The landscape of psoriasis treatments has undergone rapid change within the last decade, and the dizzying speed of drug development has not slowed, with 4 notable entries into the psoriasis treatment armamentarium within the last year: tapinarof, roflumilast, deucravacitinib, and spesolimab. Several others are in late-stage development, and these therapies represent new mechanisms, pathways, and delivery systems that will meaningfully broaden the spectrum of treatment choices for our patients. However, it can be quite difficult to keep track of all of the medication options. This review aims to present the mechanisms and data on both newly available therapeutics for psoriasis and products in the pipeline that may have a major impact on our treatment paradigm for psoriasis in the near future.
Topical Treatments
Tapinarof—Tapinarof is a topical aryl hydrocarbon receptor (AhR)–modulating agent derived from a secondary metabolite produced by a bacterial symbiont of entomopathogenic nematodes.1 Tapinarof binds and activates AhR, inducing a signaling cascade that suppresses the expression of helper T cells TH17 and TH22, upregulates skin barrier protein expression, and reduces epidermal oxidative stress.2 This is a familiar mechanism, as AhR agonism is one of the pathways modulated by coal tar. Tapinarof’s overall effects on immune function, skin barrier integrity, and antioxidant activity show great promise for the treatment of plaque psoriasis.
Two phase 3 trials (N=1025) evaluated the efficacy and safety of once-daily tapinarof cream 1% for plaque psoriasis.3 A physician global assessment (PGA) score of 0/1 occurred in 35.4% to 40.2% of patients in the tapinarof group and in 6.0% of patients in the vehicle group. At week 12, 36.1% to 47.6% of patients treated with daily applications of tapinarof cream achieved a 75% reduction in their baseline psoriasis area and severity index (PASI 75) score compared with 6.9% to 10.2% in the vehicle group.3 In a long-term extension study, a substantial remittive effect of at least 4 months off tapinarof therapy was observed in patients who achieved complete clearance (PGA=0).4 Use of tapinarof cream was associated with folliculitis in up to 23.5% of patients.3,4
Roflumilast—Phosphodiesterase 4 (PDE-4) is an intracellular enzyme involved in the regulation of cell proliferation, differentiation, and immune responses.5 The inhibition of PDE-4 decreases the expression of proinflammatory cytokines implicated in the pathogenesis of plaque psoriasis, such as tumor necrosis factor α, IFN-γ, and IL-2, IL-12, and IL-23.6 Phosphodiesterase 4–targeted therapies have been thoroughly explored to treat various inflammatory conditions, including atopic dermatitis and plaque psoriasis. The oral PDE-4 inhibitor apremilast was shown to achieve PASI 75 in approximately 30% of 562 patients, accompanied by severe gastrointestinal adverse events (AEs) including diarrhea and nausea associated with treatment.7 Local irritation from the topical PDE-4 inhibitor crisaborole for atopic dermatitis and psoriasis (where it only completed phase 2 trials) limits its widespread use. The lack of tolerable and effective treatment alternatives for psoriasis prompted the investigation of new PDE-4–targeted therapies.
Topical roflumilast is a selective, highly potent PDE-4 inhibitor with greater affinity for PDE-4 compared to crisaborole and apremilast.8 Two phase 3 trials (N=881) evaluated the efficacy and safety profile of roflumilast cream for plaque psoriasis, with a particular interest in its use for intertriginous areas.9 At week 8, 37.5% to 42.4% of roflumilast-treated patients achieved investigator global assessment (IGA) success compared with 6.1% to 6.9% of vehicle-treated patients. Intertriginous IGA success was observed in 68.1% to 71.2% of patients treated with roflumilast cream compared with 13.8% to 18.5% of vehicle-treated patients. At 8-week follow-up, 39.0% to 41.6% of roflumilast-treated patients achieved PASI 75 vs 5.3% to 7.6% of patients in the vehicle group. Few stinging, burning, or application-site reactions were reported with roflumilast, along with rare instances of gastrointestinal AEs (<4%).9
Oral Therapy
Deucravacitinib—Tyrosine kinase 2 (TYK2) mediates the intracellular signaling of the TH17 and TH1 inflammatory cytokines IL-12/IL-23 and type I interferons, respectively, the former of which are critical in the development of psoriasis via the Janus kinase (JAK) signal transducer and activator of transcription pathway.10 Deucravacitinib is an oral selective TYK2 allosteric inhibitor that binds to the regulatory domain of the enzyme rather than the active catalytic domain, where other TYK2 and JAK1, JAK2, and JAK3 inhibitors bind.11 This unique inhibitory mechanism accounts for the high functional selectivity of deucravacitinib for TYK2 vs the closely related JAK1, JAK2, and JAK3 kinases, thus avoiding the pitfall of prior JAK inhibitors that were associated with major AEs, including an increased risk for serious infections, malignancies, and thrombosis.12 The selective suppression of the inflammatory TYK2 pathway has the potential to shift future therapeutic targets to a narrower range of receptors that may contribute to favorable benefit-risk profiles.
Two phase 3 trials (N=1686) compared the efficacy and safety of deucravacitinib vs placebo and apremilast in adults with moderate to severe plaque psoriasis.13,14 At week 16, 53.0% to 58.4% of deucravacitinib-treated patients achieved PASI 75 compared with 35.1% to 39.8% of apremilast-treated patients. At 16-week follow-up, static PGA response was observed in 49.5% to 53.6% of patients in the deucravacitinib group and 32.1% to 33.9% of the apremilast group. The most frequent AEs associated with deucravacitinib therapy were nasopharyngitis and upper respiratory tract infection, whereas headache, diarrhea, and nausea were more common with apremilast. Treatment with deucravacitinib caused no meaningful changes in laboratory parameters, which are known to change with JAK1, JAK2, and JAK3 inhibitors.13,14 A long-term extension study demonstrated that deucravacitinib had persistent efficacy and consistent safety for up to 2 years.15