Market frame

This review centers on products with directly retrievable current U.S. or EU regulatory materials and company disclosures as of May 14, 2026. In that source set, the marketed IL-17 field in major Western markets is built around four branded molecules: secukinumab, ixekizumab, bimekizumab, and brodalumab. 123456

Mechanistically, the class now separates into IL-17A blockade for secukinumab and ixekizumab, dual IL-17A and IL-17F blockade for bimekizumab, and IL-17 receptor A blockade for brodalumab. That split increasingly matters in 2026 because bimekizumab has converted dual-cytokine inhibition into broader adult label expansion and new head-to-head differentiation, while brodalumab remains a more specialized psoriasis asset. 123478

Approved products at a glance

Among currently marketed products, Cosentyx shows the broadest U.S. label in the reviewed materials, spanning plaque psoriasis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, pediatric enthesitis-related arthritis, and hidradenitis suppurativa, and it also has both subcutaneous and intravenous formulations in the U.S. 1

Taltz remains a large IL-17A franchise with U.S. indications in plaque psoriasis, psoriatic arthritis, ankylosing spondylitis, and non-radiographic axial spondyloarthritis. BIMZELX now covers plaque psoriasis, psoriatic arthritis, axial disease, and hidradenitis suppurativa in adults, while SILIQ stays confined to difficult plaque psoriasis and is restricted through a REMS program because of its boxed suicidal-ideation warning. 234

Disease-by-disease competition

In plaque psoriasis, the class remains highly competitive, but bimekizumab has the clearest head-to-head differentiation in the reviewed sources. In BE RADIANT, bimekizumab delivered PASI 100 in 61.7% of patients at week 16 versus 48.9% with secukinumab and 67.0% versus 46.2% at week 48, while oral candidiasis remained an observed trade-off. 7

In psoriatic arthritis, Taltz already had head-to-head evidence against adalimumab before 2026. The SPIRIT-H2H study reported superiority on the combined endpoint of ACR50 plus PASI100 at week 24, with 36% on ixekizumab versus 28% on adalimumab in biologic-naive patients with active psoriatic arthritis and skin involvement. 9

The competitive bar in psoriatic arthritis rose again in March 2026 when UCB reported that bimekizumab achieved statistical superiority over risankizumab on ACR50 at week 16 in the BE BOLD trial. Because the reviewed source is a company topline disclosure rather than a full paper or congress dataset, the magnitude of effect beyond that primary result and the subgroup detail remain unspecified here. 8

Hidradenitis suppurativa is now one of the most important IL-17 battlegrounds. Cosentyx and BIMZELX both carry current U.S. HS labels, but bimekizumab has the deeper published pivotal dataset in the reviewed materials: in BE HEARD I and II, HiSCR50 at week 16 was 48% versus 29% and 52% versus 32% for bimekizumab every two weeks versus placebo, and BE HEARD II also met the primary endpoint with every-four-week dosing at 54% versus 32%. 1310

Safety and monitoring distinctions

Across the class, infection management is not optional. Current U.S. labels for Cosentyx, Taltz, BIMZELX, and SILIQ all require attention to infections and tuberculosis assessment, and each advises against live vaccines during treatment. Current labels for Cosentyx, Taltz, BIMZELX, and SILIQ also call out inflammatory bowel disease risk, caution, or discontinuation triggers, although the exact wording differs by product. 1234

The product-level distinctions matter. SILIQ remains the most restrictive asset because it carries a boxed warning for suicidal ideation and behavior and is dispensed only through the SILIQ REMS Program. BIMZELX does not carry a boxed warning, but its current U.S. label includes warnings on suicidal ideation and behavior, liver biochemical abnormalities, and inflammatory bowel disease in addition to infection and tuberculosis precautions. 43

Taltz's U.S. label reports a higher overall infection rate than placebo in adult plaque psoriasis trials, 27% versus 23%, and notes more frequent oral candidiasis, conjunctivitis, and tinea infections. In Europe, UCB's March 2026 safety summary for bimekizumab listed oral candidiasis frequencies of 7.3% in psoriasis, 2.3% in psoriatic arthritis, 3.7% in axial spondyloarthritis, and 5.6% in hidradenitis suppurativa, reinforcing that candidiasis is a recurring management issue for dual IL-17A and IL-17F blockade. 28

For clinicians, market-access teams, and portfolio strategists, that means class choice is no longer only an efficacy question. Psychiatric history, inflammatory bowel disease risk, need for liver monitoring, pediatric use, route of administration, and willingness to manage candidiasis can materially change where each product fits. 1234

Commercial shape and exclusivity

The class is no longer a single-product story. Novartis reported 2025 net sales of USD 6.668 billion for Cosentyx, Lilly reported approximately USD 3.563 billion for Taltz by combining USD 2.333 billion in U.S. revenue and USD 1.230 billion outside the U.S., and UCB reported EUR 2.227 billion for Bimzelx in 2025. 111213

BIMZELX is scaling from a smaller base but with unusually sharp momentum. In February 2026 reporting, UCB said BIMZELX was available in more than 50 countries, had reached more than 116,000 patients globally in 2025, and generated EUR 1.657 billion of its 2025 sales in the U.S. alone. 1314

The exclusivity picture suggests why competition will keep rising before biosimilar pressure fully arrives. In investor materials, Novartis assumes U.S. Cosentyx loss of exclusivity in 2029 based on the composition-of-matter patent while stating that it will enforce later-expiring patents as appropriate. Lilly lists Taltz compound patent expiry in 2030 in the U.S. and 2031 in major European countries, with U.S. biologics data protection to 2028. UCB lists indicative BIMZELX loss of exclusivity in 2035 in the U.S. without patent-term extension and 2036 in Europe. These company-stated dates are not the same as final legal outcomes, but they do point to a longer runway for bimekizumab than for the older IL-17A incumbents. 151214

What could reshape the class next

The most visible next-wave entrant in the reviewed materials is sonelokimab, not a broad pack of late-stage me-too biologics. MoonLake's 2025 Form 10-K describes sonelokimab as a three-VHH Nanobody with two IL-17A and IL-17F binding domains and one albumin-binding domain, and it places the asset in Phase 3 for hidradenitis suppurativa and psoriatic arthritis with additional programs in adolescent HS, palmoplantar pustulosis, and axial spondyloarthritis. 1617

In hidradenitis suppurativa, MoonLake disclosed more than 800 enrolled patients across VELA-1 and VELA-2 and said the combined Phase 3 program met primary and key secondary endpoints with p-values below 0.001 using both pre-specified strategies, although VELA-2 alone missed statistical significance under the composite strategy because of a higher-than-expected placebo response. In May 2026, the company also said its final pre-BLA FDA meeting identified no remaining filing gaps and that U.S. BLA submission is planned for the end of September 2026. 1617

Incumbents are not standing still. Novartis reported that the Phase III REPLENISH study met its primary endpoint in relapsing polymyalgia rheumatica and said full data would be submitted to health authorities in H1 2026, while UCB says it initiated three global Phase 3 pediatric bimekizumab studies in 2025 for psoriasis, hidradenitis suppurativa, and juvenile idiopathic arthritis. An inference from these disclosures is that the next phase of IL-17 competition is more likely to be shaped by label deepening and selective next-generation entrants than by a crowded wave of undifferentiated launches. 181417