Switzerland-based MoonLake Immunotherapeutics (Nasdaq: MLTX) reported Week 52 data from its Phase III VELA-1 and VELA-2 trials showing that 67.2% of adults with moderate-to-severe hidradenitis suppurativa treated with sonelokimab achieved HiSCR75 at one year — a response rate MoonLake says exceeds those reported at comparable timepoints in the pivotal trials of every currently approved biologic in the indication. With a BLA submission planned for late September 2026, the data now define the clinical package MoonLake will take to the FDA, and the strength of that package relative to UCB's Bimzelx (bimekizumab) — the most recently approved and mechanistically closest competitor — will determine whether sonelokimab can carve out meaningful market share in a rapidly crowding field.
The VELA program enrolled 838 adults across two identical, randomized, double-blind, placebo-controlled trials. The Week 52 results are as-observed analyses from 396 treated patients. Beyond the headline HiSCR75 rate, 33.1% of patients achieved HiSCR100 — complete resolution of abscesses and inflammatory nodules — and 26.0% reached IHS4-100, defined as 100% reduction in abscesses, nodules, and draining tunnels simultaneously. Quality-of-life data reinforced the efficacy signal: the mean HiSQOL score improved by approximately 15 points from baseline, representing an average shift from "severe" to "mild" disease-related impairment, and 46.5% of patients with meaningful baseline pain achieved at least a three-point reduction on the worst skin pain numerical rating scale. Approximately 90% of patients across all arms enrolled in the two-year open-label extension, a retention figure that speaks to both tolerability and the convenience of the once-monthly 120 mg subcutaneous dosing regimen. No new safety signals were detected through Week 52.
Competitive context
The HS biologic landscape has expanded considerably since AbbVie's Humira (adalimumab) received the first approval in 2015. Novartis's Cosentyx (secukinumab), an IL-17A inhibitor, was approved for adult HS in October 2023, and UCB's Bimzelx (bimekizumab), a dual IL-17A/F inhibitor, followed in November 2024. MoonLake's own press release draws a direct comparison, noting that sonelokimab's Week 52 HiSCR75 rate of 67.2% exceeds the one-year HiSCR75 rates reported for approved IL-17A inhibitors (approximately 40%) and for the approved dual IL-17A/F inhibitor (approximately 60%), based on pooled end-of-parental-trial analyses. Cross-trial comparisons are limited by differences in patient populations, trial design, and statistical handling of intercurrent events, and no head-to-head data exist. Notably, VELA-2 narrowly missed statistical significance on its primary composite endpoint at Week 16 (p=0.053), a complication MoonLake attributed to higher-than-expected placebo response driven by intercurrent events; the combined program met all primary and key secondary endpoints.
Sonelokimab is a trivalent Nanobody — a small-format biologic format derived from camelid heavy-chain antibodies — that simultaneously inhibits IL-17A and IL-17F dimers, with a third albumin-binding domain intended to extend half-life and enrich the molecule at sites of inflammatory edema. Its smaller molecular size (~40 kDa versus ~150 kDa for conventional monoclonal antibodies) is proposed to support deeper tissue penetration, though this mechanistic claim has not been directly validated against bimekizumab in HS.
Regulatory and strategic significance