MoonLake Immunotherapeutics’ stock has taken a pummeling after the biotech blamed an unexpectedly high placebo response rate for its much-hyped inflammatory disease prospect missing the key goal of one of a pair of phase 3 studies.
The company has been evaluating a single 120-mg dose of the IL-17 inhibitor, called sonelokimab, across two identical studies in 838 patients with moderate to severe hidradenitis suppurativa (HS). The primary endpoint was measured by the proportion of patients who saw at least a 75% reduction in abscess and inflammatory nodule count when compared to placebo.
The proportion of patients who achieved this primary endpoint was similar for both the VELA-1 and VELA-2 studies—at 34.8% and 35.9%, respectively. However, the placebo response rates were more varied—at 17.5% and 25.6%. The “higher-than-expected” placebo response rate in VELA-2 meant that the study by itself missed the endpoint.
Still, MoonLake said it had previously specified that it was entitled to analyze the data “irrespective of intercurrent events,” which still allowed the company to claim a win overall. Both studies also hit key secondary endpoints related to lesion count and patient-reported outcomes, the biotech noted.
“We are encouraged by the results of VELA-1, which follow the expected performance of sonelokimab in all the important metrics for patients and treating physicians,” MoonLake Chief Scientific Officer Kristian Reich, M.D., Ph.D., said in the release.
“The higher-than-expected placebo response rate in VELA-2 is disappointing but we are encouraged by the consistent performance of sonelokimab arms across all endpoints in both studies,” Reich said. “We are pleased to see a favorable safety profile consistent with previous studies, with no new safety signals.”
The warm words weren’t enough to reassure investors, which sent the company’s stock plummeting 87% to $7.81 in premarket trading Monday morning from a Friday closing price of $61.99.
MoonLake will be discussing the unexpected placebo data with regulators while the company continues to chart a path toward a hoped-for approval for the drug. As well as the VELA-1 and VELA-2 studies, which are due to read out 52-week data in the second quarter of 2026, there is also a phase 2 study in palmoplantar pustulosis due to read out this year, and next year brings the results of a phase 2 study in axial spondyloarthritis and phase 3 studies in adolescent HS and psoriatic arthritis.
Analysts at Leerink Partners described yesterday’s readout as “arguably falling into the worst case outcome” for the VELA program.
“We believe these results have introduced uncertainty around sonelokimab’s path to approval in HS on basis of the two VELA trials, though we await more details on a potential path forward and FDA’s receptivity to pooled results, treatment policy analyses, and MoonLake’s arguments around the totality of data,” they wrote in a Sept. 28 note.
Reich said the company is still convinced by sonelokimab’s “convenient dosing, the efficacy data in the lesion-based metrics and the patient-reported outcomes.” But yesterday's mixed data may take the shine off an asset that was reportedly attracting Big Pharma attention.
The Financial Times reported in June that Merck & Co. had submitted a nonbinding offer that valued MoonLake at more than $3 billion earlier this year. The offer was rejected, but talks could be revived, the FT reported at the time.
MoonLake licensed sonelokimab from Germany’s Merck KGaA in 2021. The molecule originated at the nanobody specialist Ablynx, which is now part of Sanofi.