MoonLake's Sonelokimab Holds 67% Response at Week 52 in Phase 3 Hidradenitis Suppurativa Trials, Setting Up a September FDA Filing
Full Week 52 data from MoonLake's VELA program show sustained response rates for the IL-17 Nanobody, nine months after one of its two pivotal trials missed its primary endpoint.
Overview
MoonLake Immunotherapeutics on June 21 released the full Week 52 results from its Phase 3 VELA program testing the antibody fragment sonelokimab in hidradenitis suppurativa, reporting that 67.2 percent of treated patients achieved a 75 percent reduction in abscess and inflammatory-nodule counts (HiSCR75) one year into treatment, according to MoonLake. The company said it plans to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration at the end of September 2026.
The one-year readout follows a turbulent September 2025, when topline Week 16 data from the same program split across the two pivotal trials and sent the company’s shares down sharply.
What We Know
The VELA program recruited a total of 838 patients across two identically designed Phase 3 trials, VELA-1 and VELA-2, dosing sonelokimab at 120mg once every four weeks, according to MoonLake. Sonelokimab is a humanized Nanobody that, per the company, selectively binds with high affinity to the inflammatory cytokines IL-17A and IL-17F.
At Week 52, across both trials, 67.2 percent of patients on sonelokimab achieved HiSCR75, 33.1 percent reached the more stringent HiSCR100 (complete clearance of abscesses and inflammatory nodules), and 26.0 percent achieved an IHS4-100 response, MoonLake reported. Broken out by study, VELA-1 showed 68.3 percent HiSCR75 and 31.2 percent HiSCR100, while VELA-2 showed 66.0 percent HiSCR75 and 35.1 percent HiSCR100, according to figures carried by StockTitan.
The company also reported patient-reported outcomes. The mean change in HiSQOL, a quality-of-life measure, was -15.3 points in VELA-1 and -14.8 points in VELA-2 between the end of the trial and baseline, and 46.5 percent of patients experienced what the company described as a marked reduction in pain, defined as at least a 3-point improvement from baseline in the worst skin pain Numerical Rating Scale (NRS), according to MoonLake. The company said no new safety signals were detected in the VELA trials through Week 52.
“The final Week 52 data from the VELA program confirm the strength of SLK across most, if not all, metrics that matter in HS: strong early efficacy, sustained and leading improvement over time, a consistent safety profile and great convenience in dosing,” said Dr. Jorge Santos da Silva, MoonLake’s Founder and Chief Executive Officer, in the statement. Prof. Kristian Reich, Founder and Chief Scientific Officer, added: “What is particularly compelling in the final Week 52 dataset is how consistently the strong clinical efficacy of SLK is reflected in Patient-Reported Outcomes.”
Hidradenitis suppurativa is a chronic inflammatory skin disease that produces painful nodules and abscesses, typically in skin folds. The disease affects an estimated 2 percent of the population, with three times more females affected than males, and real-world U.S. data indicate at least 2 million unique patients were diagnosed with and treated for HS between 2016 and 2023, according to MoonLake.
Background: A Split Result at Week 16
The Week 52 figures arrive nine months after the program’s first major test. When MoonLake released topline Week 16 data, the two trials diverged. In VELA-1, sonelokimab achieved statistical significance for all primary and key secondary endpoints, with a HiSCR75 delta to placebo of 17 percent (p<0.001), according to MoonLake. In VELA-2, the company said intercurrent events in a higher-than-expected placebo arm precluded the study from achieving statistical significance on the Week 16 primary endpoint using the composite strategy, where the delta to placebo was 9 percent (p=0.053).
That split hit the company hard. Shares of MoonLake Immunotherapeutics lost more than 80 percent of their value on Sept. 29, 2025, when the topline results landed, BioPharma Dive reported. In VELA-1, 35 percent of sonelokimab recipients met the primary endpoint at four months versus 18 percent on placebo, while VELA-2 failed to meet its primary objective, with the company attributing the miss to an unexpectedly high placebo response, the outlet reported. Some analysts at the time described sonelokimab as uncompetitive with Bimzelx (bimekizumab), according to BioPharma Dive, which also named AbbVie’s Humira (adalimumab) and Novartis’ Cosentyx (secukinumab) among the biologics already available for the disease.
What We Don’t Know
The Week 52 data were disclosed in a company press release ahead of an investor day scheduled for June 22, 2026, and have not yet been published in a peer-reviewed journal or presented with full statistical detail at a medical meeting. The company’s HiSCR75 figures at Week 52 are reported as single-arm response rates in patients who continued on sonelokimab, rather than as a fresh placebo-controlled comparison, so they are not directly comparable to the Week 16 placebo-adjusted deltas.
MoonLake’s own characterization of the data as best-in-class is a competitive claim that cannot be verified from the VELA trials alone, which did not include active comparators. The FDA’s response to the planned BLA, and whether the agency views the VELA-2 Week 16 miss as a barrier to approval, remains unknown.