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• Results from the Phase 3 VELA clinical trials in adults with moderate-to-severe hidradenitis suppurativa (HS) show that clinical responses continue to improve to Week 40, with 62% of patients treated with sonelokimab (SLK) achieving HiSCR75 and up to 32% of patients achieving HiSCR100 
• An analysis of different hallmark lesions of HS shows that up to 25% of patients achieved inflammatory remission at Week 40, defined as a 100% reduction in abscesses (A100), nodules (N100) and draining tunnels (DT100)
• Patients treated with SLK also showed substantial improvements in HiSQOL items at week 40 versus baseline, ranging from 41% (pain), to 54% (walking, getting dressed) to 62% (down or depressed)
• Up to 43% of patients achieved an at least 3-point improvement from baseline in the worst skin pain NRS, while 65% of patients achieved an improvement of at least 4 points from baseline in DLQI
• No new safety signals were detected in the VELA trials to-date
• Detailed results will be presented at the S034 Late-Breaking Research: Session 2 by Prof. Alexa Kimball, Investigator at Beth Israel Deaconess Medical Center, and Professor of Dermatology at Harvard Medical School, at the 2026 AAD Annual Meeting on March 28, 2026

ZUG, Switzerland, March 28, 2026 – MoonLake Immunotherapeutics (NASDAQ: MLTX) (MoonLake or the Company), a clinical-stage biotechnology company focused on creating next-level therapies for inflammatory diseases, today announces long-term Week 40 results of the Phase 3 VELA-1 and VELA-2 clinical trials of its registrational global program in patients with moderate-to-severe HS and confirms the presentation of the data at the 2026 American Academy of Dermatology (AAD) Annual Meeting later today.

The Phase 3 VELA program in adults with moderate-to-severe HS used the higher clinical response level of HS Clinical Response (HiSCR) 75 as the primary endpoint, which defines a response as an at least 75% reduction in abscess and inflammatory nodule count, with no increase from baseline in abscess or draining tunnel count. Key secondary endpoints included the change from baseline in the HS Quality of Life score (HiSQOL) as well as other scores that reflect the evolving needs of HS patients, treating physicians and regulators. These included the percentage of participants achieving at least a 55% reduction in the International HS Severity Scoring System (IHS4-55), the percentage of participants achieving at least a 3-point improvement from baseline in the worst skin pain Numerical Rating Scale (NRS) among participants with a baseline score of at least 3 points, and the percentage of patients achieving a Dermatology Quality of Life Index (DLQI) total score improvement of ≥4 (minimal clinically important difference), among participants with a baseline DLQI ≥4. A total of 838 patients were enrolled across both trials. Following the primary endpoint at Week 16, patients in the placebo arm were switched to receive SLK treatment for the remaining duration of the trial until Week 52. Patients originally randomized to the SLK arm continued to receive SLK at the monthly 120mg maintenance dose. All patients have completed Week 40 and discontinuation rates were at the low end to those observed in other pivotal HS trials. After Week 52, patients have the opportunity to switch into a two-year open-label extension trial.

SLK demonstrated continued improvement of clinical scores and Patient Reported Outcomes (PROs) at Week 40. Across both VELA-1 and VELA-2, 62% of patients treated with SLK achieved HiSCR75 response and up to 32% of patients achieved HiSCR100 response at Week 40 (as observed). The results were consistent across both trials (VELA-1: 61.9% HiSCR75, 32.4% HiSCR100; VELA-2: 61.8% HiSCR75, 28.1% HiSCR100; as observed). Up to 77% of patients achieved an IHS-4 55 response (VELA-1: 74.3%, VELA-2: 77.4%; as observed) and up to 25% of patients achieved inflammatory remission at Week 40 (A100 + DT100 + N100; VELA-1: 25.2%, VELA-2: 21.1%; as observed).

With 62% of SLK patients reaching a HiSCR75 response already at Week 40, SLK sets a new standard in long-term lesion control of HS. Approved IL-17A and IL17A & F inhibitors reported HiSCR75 response rates of approximately 40% and 60%, respectively, at the 1-year mark of their respective pivotal trials (approved doses, pooled analysis across pivotal trials).

The strong long-term clinical responses were accompanied by continued improvement in PROs, which reflect critical quality of life outcomes for patients with HS. Patients treated with SLK showed a significant improvement of HiSQOL score at Week 40 with a -11.8 change from baseline in VELA-1, and -12.4 change from baseline in VELA-2 (mean HiSQOL at baseline of 26.5 (VELA-1) and 28.0 (VELA-2); as observed). While 59% of patients were within the “very severe” category on the HiSQOL severity score at baseline, 63% of patients were in the “mild / none” category at Week 40 (as observed, pooled). Improvements versus baseline in HiSQOL-Mini items ranged from 41% (pain), to 54% (walking, getting dressed) to 62% (down or depressed) at Week 40 (in patients with baseline >0, as observed, pooled). In addition, up to 43% of patients experienced a marked reduction of pain, as measured by an at least 3-point improvement from baseline in the worst skin pain NRS (VELA-1: 43.2%, VELA-2: 37.2%; as observed, baseline score of at least three points). 65% of patients achieved a meaningful (at least four points from baseline) improvement in DLQI (VELA-1: 64.6%, VELA-2: 65.3%; as observed, baseline DLQI of at least four points).

The safety profile of SLK in the VELA clinical trials remains consistent over time, with no new safety signals detected.

Prof. Alexa Kimball, President and CEO of Harvard Medical Faculty Physicians at Beth Israel Deaconess Medical Center, Professor of Dermatology at Harvard Medical School said: “The Week 40 results from the VELA trials show an early and increasing clinical benefit over time for patients treated with sonelokimab, addressing a critical goal in HS treatment: long-term disease control. The consistency of the VELA data over time reinforces the opportunity for sonelokimab to address this important unmet need for patients living with HS.”

Details of the Week 40 results from Phase 3 VELA clinical trials in HS will be presented by Prof. Alexa Kimball at the 2026 AAD Annual Meeting (S034 Late-Breaking Research: Session 2). The presentation titled Sonelokimab in Moderate-to-Severe HS: Long-term Results through Week 40 of Two Phase 3 Trials will be on March 28, 2026 at 4pm – 4.12pm ET (2pm – 2.12pm MT).

Important upcoming anticipated milestones for MoonLake:  

• Q2 2026: 52-week data of the VELA-1 and VELA-2 trials in HS
• Mid 2026: Primary endpoint readout of the Phase 3 IZAR-1 trial in PsA
• H2 2026: Submission of a BLA for HS
• H2 2026: Primary endpoint readout of the Phase 3 IZAR-2 trial in PsA

-Ends-

MoonLake Immunotherapeutics

MoonLake Immunotherapeutics is a clinical-stage biopharmaceutical company unlocking the potential of sonelokimab, a novel investigational Nanobody^® for the treatment of inflammatory disease, to revolutionize outcomes for patients. Sonelokimab inhibits IL-17A and IL-17F by inhibiting the IL-17A/A, IL-17A/F, and IL-17F/F dimers that drive inflammation. The Company’s focus is on inflammatory diseases with a major unmet need, including hidradenitis suppurativa, psoriatic arthritis, axial spondyloarthritis and palmoplantar pustulosis – conditions affecting millions of people worldwide with a large need for improved treatment options. MoonLake was founded in 2021 and is headquartered in Zug, Switzerland. Further information is available at www.moonlaketx.com.

About Nanobodies

^®


Nanobodies^® represent a new generation of antibody-derived targeted therapies. They consist of one or more domains based on the small antigen-binding variable regions of heavy-chain-only antibodies (VHH). Nanobodies^® have a number of potential advantages over traditional antibodies, including their small size, enhanced tissue penetration, resistance to temperature changes, ease of manufacturing, and their ability to be designed into multivalent therapeutic molecules with bespoke target combinations.

The terms Nanobody^® and Nanobodies^® are trademarks of Ablynx, a Sanofi company.

About Sonelokimab

Sonelokimab (M1095) is an investigational ~40 kDa humanized Nanobody^® consisting of three VHHs covalently linked by flexible glycine-serine spacers. With two domains, sonelokimab selectively binds with high affinity to IL-17A and IL-17F, thereby inhibiting the IL-17A/A, IL-17A/F, and IL-17F/F dimers. A third central domain binds to human albumin, facilitating further enrichment of sonelokimab at sites of inflammatory edema.

Sonelokimab is being assessed in two lead indications, hidradenitis suppurativa (HS) and psoriatic arthritis (PsA), and the Company is pursuing other indications in dermatology and rheumatology, including adolescent HS, palmoplantar pustulosis (PPP) and axial spondyloarthritis (axSpA).

For adults with HS, sonelokimab is being assessed in two identical Phase 3 trials, the VELA-1 and VELA-2 trials, using the higher clinical response level of HS Clinical Response (HiSCR) 75 as the primary endpoint, which defines a response as an at least 75% reduction in abscess and inflammatory nodule count, with no increase from baseline in abscess or draining tunnel count. In September 2025, the primary endpoint data from the VELA-1 and VELA-2 clinical trials were announced. In the combined VELA program, patients treated with SLK experienced a clinically meaningful and statistically significant improvement across all primary and key secondary endpoints using both pre-specified strategies (p<0.001). In VELA-1, SLK achieved statistical significance for all primary and key secondary endpoints using both pre-specified strategies (HiSCR75, delta to placebo of 17%, p<0.001). In VELA-2, intercurrent events in the higher-than-expected placebo arm precluded the study from achieving statistical significance in the week 16 primary endpoint using the composite strategy (HiSCR75, delta to placebo of 9%, p=0.053). From week 16, all patients are expected to continue to receive the 120mg dose of SLK through to 48 weeks, with a last assessment planned at week 52, followed by an open-label extension for up to two years. The safety profile of sonelokimab in the VELA trials was consistent with previous trials with no new safety signals detected.

Sonelokimab is currently undergoing evaluation in the VELA-TEEN Phase 3 trial, which is the first clinical study specifically focused on adolescent patients with moderate-to-severe HS.

For PsA, sonelokimab is being assessed in the Phase 3 trials, IZAR-1 and IZAR-2, following the announcement in March 2024 of the full dataset from the global Phase 2 ARGO trial (M1095-PSA-201) evaluating the efficacy and safety of the Nanobody^® sonelokimab over 24 weeks in patients with active PsA. Significant improvements were observed across all key outcomes, including approximately 60% of patients treated with sonelokimab achieving an American College of Rheumatology (ACR) 50 response and Minimal Disease Activity (MDA) at week 24. This followed the positive top-line results in November 2023, where the trial met its primary endpoint with a statistically significant greater proportion of patients treated with either sonelokimab 60mg or 120mg (with induction) achieving an ACR50 response compared to those on placebo at week 12. All key secondary endpoints in the trial were met for the 60mg and 120mg doses with induction. The safety profile of sonelokimab in the ARGO trial was consistent with previous trials with no new safety signals detected.

Sonelokimab is also being assessed in PPP, a debilitating inflammatory skin condition affecting a significant number of patients, including in the completed Phase 2 LEDA program. In the Phase 2 LEDA clinical trial in PPP, SLK demonstrated clinically meaningful and statistically significant benefit. Patients treated with SLK achieved a mean percent change from baseline in the Palmoplantar Pustular Psoriasis Area and Severity Index (PPPASI) of 64% at week 16, and 39% of patients achieved a ≥75% reduction in the PPPASI (PPPASI75), suggesting that SLK could provide clinically meaningful improvements in this disease for which there are currently no approved therapies. The safety profile of SLK in the LEDA trial was consistent with previous trials with no new safety signals detected. 

Additionally, Sonelokimab is being assessed in the ongoing Phase 2 S-OLARIS and P-OLARIS trials for active axSpA and PsA, respectively. Both trials feature an innovative design complementing traditional clinical outcomes with cellular imaging techniques.

Sonelokimab has also been assessed in a randomized, placebo-controlled third-party Phase 2b trial (NCT03384745) in 313 patients with moderate-to-severe plaque-type psoriasis. High threshold clinical responses (Investigator’s Global Assessment Score 0 or 1, and Psoriasis Area and Severity Index 90/100) were observed in patients with moderate-to-severe plaque-type psoriasis. Sonelokimab generally presented a safety profile similar to the active control, secukinumab (Papp KA, et al. Lancet. 2021; 397:1564-1575).

In an earlier third-party Phase 1 trial in patients with moderate-to-severe plaque-type psoriasis, sonelokimab decreased (to normal skin levels) the cutaneous gene expression of pro-inflammatory cytokines and chemokines (Svecova D. J Am Acad Dermatol. 2019; 81:196–203).

About the VELA program

The Phase 3 VELA program has enrolled over 800 patients across VELA-1 and VELA-2. Both global, randomized, double-blind, and placebo-controlled trials are identical in design evaluating the efficacy and safety of the Nanobody^® sonelokimab, administered subcutaneously, in adult patients with active moderate-to-severe hidradenitis suppurativa. Similar to the design of the landmark Phase 2 MIRA trial, the primary endpoint is the percentage of participants achieving Hidradenitis Suppurativa Clinical Response (HiSCR) 75, defined as a ≥75% reduction in total abscess and inflammatory nodule (AN) count with no increase in abscess or draining tunnel count relative to baseline. The trials also evaluate a number of secondary endpoints, including the proportion of patients achieving HiSCR50, the change from baseline in International Hidradenitis Suppurativa Severity Score System (IHS4), the proportion of patients achieving a Dermatology Life Quality Index (DLQI) total reduction of ≥4, the proportion of patients achieving at least 50% reduction from baseline in Numerical Rating Scale (NRS50) in the Patient’s Global Assessment of Skin Pain (PGA Skin Pain) and complete resolution of Draining Tunnels (DT100). The VELA protocols and statistical analysis plans were prepared in accordance with regulatory agency advice and include two analysis strategies. The composite strategy for the VELA trials (also referred to as the primary estimand) is the primary statistical analysis. The protocol specifies the treatment policy strategy as the alternative method of handling intercurrent events to test the robustness of the VELA data. The trials compare a single 120mg dose of sonelokimab to placebo with HiSCR75 reading out at week 16. Results of the week 16 data were announced in September 2025. Further details are available under NCT06411899 and NCT06411379 at www.clinicaltrials.gov.

About the MIRA trial

The MIRA trial (M1095-HS-201) is a global, randomized, double-blind, placebo-controlled Phase 2 trial to evaluate the efficacy and safety of the Nanobody^® sonelokimab, administered subcutaneously, in the treatment of adult patients with active moderate-to-severe hidradenitis suppurativa. The trial recruited 234 patients, with the aim to evaluate two different doses of sonelokimab (120mg and 240mg) with placebo control and adalimumab as an active reference arm. The primary endpoint of the trial is the percentage of participants achieving Hidradenitis Suppurativa Clinical Response 75 (HiSCR75), defined as a ≥75% reduction in total abscess and inflammatory nodule (AN) count with no increase in abscess or draining tunnel count relative to baseline. The trial also evaluated a number of secondary endpoints, including the proportion of patients achieving HiSCR50, the change from baseline in International Hidradenitis Suppurativa Severity Score System (IHS4), the proportion of patients achieving a Dermatology Life Quality Index (DLQI) total score of ≤5, and the proportion of patients achieving at least 30% reduction from baseline in Numerical Rating Scale (NRS30) in the Patient’s Global Assessment of Skin Pain (PGA Skin Pain). Further details are available under NCT05322473 at www.clinicaltrials.gov.

About the VELA-TEEN trial

The Phase 3 VELA-TEEN trial is an open-label, single-arm trial designed to evaluate sonelokimab 120mg administered subcutaneously once every two weeks (Q2W) until week six and once every four weeks (Q4W) from week eight onwards. The trial aims to enroll 30-35 adolescents, aged 12-17, with moderate-to-severe hidradenitis suppurativa, from U.S. sites experienced in clinical trials and pediatric dermatology. The primary trial phase will be 24 weeks with a primary endpoint evaluating the pharmacokinetics, safety, and tolerability of sonelokimab. VELA-TEEN will also evaluate several secondary endpoints, including the proportion of patients achieving the higher clinical response measure of the Hidradenitis Suppurativa Clinical Response Score (HiSCR) 75, in addition to HiSCR50. Other outcomes are the change from baseline in the International Hidradenitis Suppurativa Severity Score System (IHS4), which includes the quantitative measure of draining tunnels, and the proportion of patients achieving a meaningful reduction of the Children’s Dermatology Life Quality Index (CDLQI) and the Patients Global Assessment of Skin Pain (PGA Skin Pain). Further details are available under NCT06768671 at www.clinicaltrials.gov.

About Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a severely debilitating chronic skin condition resulting in irreversible tissue destruction. HS manifests as painful inflammatory skin lesions, typically around the armpits, groin, and buttocks. Over time, uncontrolled and inadequately treated inflammation can result in irreversible tissue destruction and scarring. The disease affects an estimated 2% of the population, with three times more females affected than males. Real-world data in the United States indicates that at least 2 million unique patients have been diagnosed with and treated for HS between 2016 and 2023 alone, highlighting a significant unmet need and impact on healthcare systems, and a market opportunity projected to reach $15bn by 2035. Onset typically occurs in early adulthood and HS has a profound negative impact on quality of life, with a higher morbidity than other dermatologic conditions. There is increasing scientific evidence to support IL-17A- and IL-17F-mediated inflammation as a key driver of the pathogenesis of HS, with other identified risk factors including genetics, cigarette smoking, and obesity.

About the IZAR Program

IZAR-1 (NCT06641076) and IZAR-2 (NCT06641089) are global, randomized, double-blind, placebo-controlled Phase 3 trials designed to evaluate the efficacy and safety of sonelokimab compared with placebo in a total of approximately 1,500 adults with active psoriatic arthritis (PsA), with a primary endpoint of superiority to placebo in American College of Rheumatology (ACR) 50 response at Week 16. IZAR-1 is expected to enroll biologic-naïve patients and include an evaluation of radiographic progression, while IZAR-2 is expected to enroll patients with an inadequate response to tumor necrosis factor-α inhibitors (TNF-IR) — reflecting patients commonly seen in clinical practice — and is the first PsA trial to include a risankizumab active reference arm. Both trials will also assess a range of secondary endpoints reflecting the multiple disease manifestations characteristic of PsA. These include skin and nail outcomes, multidomain outcomes, and patient-reported outcome measures such as pain and quality of life assessments. Further details are available under NCT06641076 and NCT06641089 at www.clinicaltrials.gov.

About Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic, progressive and complex inflammatory disease that manifests across multiple domains, leading to substantial functional impairment and decreased quality of life. The clinical features of PsA are diverse, comprising both musculoskeletal (peripheral arthritis, spondylitis, dactylitis, and enthesitis) and non-musculoskeletal (skin and nail disease) domains. PsA occurs in up to 30% of patients with psoriasis, most commonly those aged between 30 and 60 years. Although the exact mechanism of disease is not fully understood, evidence suggests that activation of the IL-17 pathway plays an important role in the disease pathophysiology.

About the S-OLARIS trial

The S-OLARIS trial (M1095-axSpA-201) is a Phase 2 trial designed to evaluate the efficacy and safety of sonelokimab 60mg administered subcutaneously in adult patients with active axial spondyloarthritis (axSpA). The trial recruited 26 patients. The primary endpoint is the change from baseline (CfB) in 18F-NaF SUVmax signals at week 12 in the sacroiliac joints and spine as detected by PET. Throughout the trial, several other endpoints will be assessed including established clinical disease activity outcomes (e.g., ASAS), scores related to physical function, spinal mobility, and enthesitis as well as patient reported outcomes. The trial also features an innovative exploratory peripheral blood and tissue biomarker program.

The trial design has been informed by previous successful studies of sonelokimab, including the landmark Phase 2 ARGO trial in psoriatic arthritis, which identified the optimal dosing and demonstrated the potential of sonelokimab to target deep tissue inflammation effectively. Further details are available under EUCT number 2024-513498-36-00 at https://euclinicaltrials.eu.

About Axial Spondyloarthritis

Axial Spondyloarthritis (axSpA) typically impacts young people, with diagnosis based on chronic inflammatory back pain lasting more than three months with onset under 45 years of age. Advanced disease can lead to progressive and pathologic bone formation and joint fusion, severely limiting spinal mobility. Global reported prevalence of axSpA ranges from 0.5% to 1.5%. AxSpA can be categorized by disease progression into two subtypes: non-radiographic axSpA and ankylosing spondylitis (AS), also known as radiographic axSpA, which is diagnosed based on radiographic evidence of structural changes to the sacroiliac joints. Patients with axSpA experience fatigue, persistent morning stiffness, and pain that worsens at night and can disrupt sleep. Many patients also face the burden of comorbidities such as psoriatic arthritis and psoriasis. Studies have found elevated IL-17 levels in the blood and synovial fluid of patients with axSpA, and IL-17A and IL-17F are both thought to be key contributors to pathogenesis across the spondyloarthropathies.

About the LEDA Trial

The LEDA trial (M1095-PPP-201) is a Phase 2 trial designed to evaluate the efficacy and safety of sonelokimab 120mg administered subcutaneously in adult patients with palmoplantar pustulosis (PPP). The trial recruited 32 patients. The primary endpoint of the trial is percent change from baseline in Palmoplantar Psoriasis Area and Severity Index (ppPASI) with important secondary endpoints including ppPASI75 (at least 75% improvement in the ppPASI). The LEDA trial features an innovative translational research program using peripheral blood and tissue biomarkers as trial controls.

The trial design has been informed by previous successful studies of sonelokimab, including the landmark Phase 2 MIRA trial in hidradenitis suppurativa, which identified the optimal dosing and demonstrated the potential of sonelokimab to target deep tissue inflammation effectively. Further details are available under EUCT number 2024-513305-32-00 at https://euclinicaltrials.eu.

About Palmoplantar Pustulosis

Palmoplantar Pustulosis (PPP) is characterized by the development of blister-like pustules within erythematous, scaly plaques on the palms and the soles of the feet. PPP typically develops in adulthood, more frequently impacts females. Patients frequently experience significant pain, burning, and itching sensations on the palms and soles of the feet which can be debilitating and impair their ability to work, sleep, or perform other activities of daily living. Currently, the treatment of PPP is challenging with a significant unmet need for novel therapies to reduce the symptom burden for patients. Evidence suggests that activation of the IL-17 pathway has an important role in disease pathophysiology.

Cautionary Statement Regarding Forward Looking Statements

This press release contains certain “forward-looking statements” within the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Forward-looking statements include, but are not limited to, statements regarding MoonLake’s expectations, hopes, beliefs, intentions or strategies regarding the future including, without limitation, statements regarding: the efficacy and safety of sonelokimab for the treatment of moderate-to-severe HS; potential market opportunities for sonelokimab; and upcoming anticipated clinical milestones, including data of the VELA-1 and VELA-2 trials in HS, the primary endpoint readouts of the Phase 3 IZAR-trial in PsA, Phase 3 VELA-TEEN trial in adolescent HS and Phase 3 IZAR-2 trial in PsA and submission of a BLA for HS. In addition, any statements that refer to projections, forecasts, or other characterizations of future events or circumstances, including any underlying assumptions, are forward looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that statement is not forward looking.

Forward-looking statements are based on current expectations and assumptions that, while considered reasonable by MoonLake and its management, as the case may be, are inherently uncertain. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. Actual results could differ materially from those anticipated in such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, risks and uncertainties associated with MoonLake’s business in general and limited operating history; difficulty enrolling patients in clinical trials; state and federal healthcare reform measures that could result in reduced demand for MoonLake’s product candidates; reliance on third parties to conduct and support its preclinical studies and clinical trials; and the other risks described in or incorporated by reference into MoonLake’s Annual Report on Form 10-K for the year ended December 31, 2025 and subsequent filings with the Securities and Exchange Commission.

Nothing in this press release should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this press release, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. MoonLake does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements to reflect any change in its expectations or in the events, conditions or circumstances on which any such statement is based.

Dr. Kimball is a paid consultant for MoonLake Immunotherapeutics.

Contacts:

MoonLake Immunotherapeutics Media & Investors Relations

[email protected]

ICR Healthcare

Mary-Jane Elliott, Sarah Elton-Farr, Ashley Tapp
Tel: +44 (0) 20 3709 5700
[email protected]

• In the Phase 2 part of the AMETHYST study, litifilimab met the primary endpoint of reduction of disease activity in people living with CLE at Week 16, with more litifilimab participants achieving clear / almost clear skin
• Following positive Phase 2 LILAC results, litifilimab is the only investigational program with consistent, positive efficacy results in multiple CLE studies; if approved litifilimab could be the first targeted therapy for this disease
• CLE is a serious autoimmune disease that impacts the daily lives of patients and can lead to permanent scarring and disfigurement

CAMBRIDGE, Mass., March 28, 2026 (GLOBE NEWSWIRE) — Biogen Inc. (Nasdaq: BIIB) announced positive results from the Phase 2 part of the AMETHYST Phase 2/3 study (Part A) of litifilimab in people living with cutaneous lupus erythematosus (CLE). Litifilimab is the first humanized IgG1 monoclonal antibody (mAb) targeting blood dendritic cell antigen 2 (BDCA2), which has the potential to become the first innovative therapy approved for CLE in 70 years. Part A of AMETHYST evaluated the efficacy and safety of litifilimab through week 24, with reductions in skin disease activity reported across several measures. Results are consistent with the earlier positive Phase 2 LILAC study reported in The New England Journal of Medicine. Phase 2 results from LILAC and AMETHYST supported litifilimab’s recently granted U.S. Food and Drug Administration (FDA) Breakthrough Therapy Designation. Results are being presented today at the American Academy of Dermatology (AAD) Annual Meeting.

“We now have consistent results from two Phase 2 studies of litifilimab showing notable reductions in CLE skin disease activity, representing a significant moment for this program. I am encouraged by these results, which support the potential to bring litifilimab to patients with cutaneous lupus erythematosus, a condition where no targeted therapies are currently approved and where there are significant unmet needs,” said Joseph F. Merola, M.D., Professor and Chair, Department of Dermatology and Professor of Internal Medicine in the Division of Rheumatic Diseases, UT Southwestern Medical Center. “These findings, alongside the FDA Breakthrough Therapy Designation, underscore the potential, if approved, of litifilimab for patients living with this challenging disease. In addition to the efficacy results, litifilimab demonstrated a safety profile consistent with prior studies. Importantly, this trial intentionally enrolled a globally representative population reflective of the heterogeneity of CLE, including many participants with moderate to severe disease at baseline.”

CLE is a complex, heterogenous disease that affects millions of people around the world. Today there are no targeted therapies approved to treat CLE.

AMETHYST is an ongoing seamless two-part, multicenter, double-blind, placebo controlled, randomized study to evaluate the efficacy and safety of litifilimab compared to placebo in participants with a variety of CLE severities. Participants are randomized to receive subcutaneous treatment with litifilimab with standard of care (SoC) or placebo every four weeks in addition to SoC. All participants will receive litifilimab during the 28-week extended treatment period from Weeks 24 to 48. Results reported here are from the double-blind, placebo-controlled Phase 2 (Part A) portion of AMETHYST, Week 0 to 24. In the study, 74% of participants are women and 33% are non-white. This demographic distribution is consistent with the epidemiology of CLE which disproportionately affects women and diverse ethno-racial groups. The Phase 3 part of the study is ongoing and results remain blinded.  

AMETHYST Part A met its primary endpoint with litifilimab demonstrating a statistically significant 11.8% higher reduction in disease activity in people living with CLE (95% confidence interval [CI]: 1.39, 22.27; p < 0.05) as measured by the Cutaneous Lupus Activity Investigators’ Global Assessment Revised (CLA-IGA-R) erythema score of 0-1 (clear/almost clear) at Week 16, compared to placebo (14.7% vs. 2.9%). Secondary endpoints, including the following, were not adjusted for multiplicity in Part A and therefore statistical significance cannot be demonstrated. Litifilimab was associated with rapid and continued improvement in skin disease activity with separation from placebo observed as early as Week 4 (19.3% vs. 5.5%; Δ= 13.8; CI: 1.19, 26.46), as measured by Cutaneous Lupus Erythematosus Disease Area and Severity Index Activity-50 (CLASI-50) response through Week 24 (40.8% vs. 21%; Δ= 19.8; CI: 1.46, 38.15). More participants receiving litifilimab achieved a response compared to placebo (21.7% vs 5.8%), as measured by CLASI-70 at Week 24. CLASI-50 and CLASI-70 responses are defined as 50 percent and 70 percent improvements from baseline in CLASI-A score, respectively. Additionally, 1 in 6 participants receiving litifilimab achieved a CLASI 0-3 score, defined as no or minimal disease activity, compared to placebo at Week 24 (16.3% vs 0%; Δ= 16.3; CI: 7.07, 25.62).

Litifilimab was generally well tolerated in Part A of the AMETHYST study and tolerability was consistent with the safety profile established in completed studies, including the Phase 2 LILAC study. Adverse events (AEs) were reported in 74.6% (44/59) and 64.7% (22/34) of participants receiving litifilimab and placebo, respectively, in the 24-week period. Most AEs were mild to moderate in severity. Serious adverse events occurred in 6.8% (4/59) and 2.9% (1/34) of participants receiving litifilimab and placebo, respectively.

“Cutaneous lupus erythematosus not only leaves scars but can also have a profound emotional and social impact on those living with the disease. With no approved targeted disease-modifying treatments, options for people living with CLE are very limited,” said Daniel Quirk, MD, Chief Medical Officer at Biogen. “We are excited to see results from two studies in which litifilimab was generally well tolerated and was associated with improvement in skin disease in a representative population, giving us encouraging momentum as we advance the Phase 3 program. The work Biogen has done in lupus and in CLE in particular demonstrates Biogen’s commitment to tackling diseases where options are limited or nonexistent.”

About AMETHYST
AMETHYST is a two-part, Phase 2/3 multicenter, double-blind, placebo controlled, randomized study to evaluate the efficacy and safety of litifilimab compared to placebo. The study aims to assess the efficacy of litifilimab in participants with active subacute cutaneous lupus erythematosus (SCLE) and/or chronic cutaneous lupus erythematosus (CCLE) who are refractory or intolerant to antimalarial therapy. The Phase 2 and Phase 3 parts of the study will each be 52 weeks in duration. Participants will be randomized to receive subcutaneous treatment with litifilimab or placebo every four weeks for 20 weeks with an additional dose at Week 2. All participants will receive litifilimab during the 28-week extended treatment period from Weeks 24 to 48. More information on the AMETHYST study (NCT05531565) is available at clinicaltrials.gov.

About Litifilimab (BIIB059)

Litifilimab (known as BIIB059), discovered and developed in-house by Biogen scientists, is a humanized IgG1 monoclonal antibody (mAb) targeting BDCA2 and is being investigated for the potential treatment of systemic lupus erythematosus (SLE) and cutaneous lupus erythematosus (CLE). BDCA2 is a receptor that is predominantly expressed on a subset of human immune cells called Plasmacytoid Dendritic Cells (pDCs). Binding of litifilimab to BDCA2 has been shown to reduce production of pro-inflammatory molecules by pDCs, including type-I interferon (IFN-I) as well as other cytokines and chemokines.^1,2 These pro-inflammatory mediators are thought to play a major role in the pathogenesis of systemic and cutaneous lupus.

Litifilimab is an investigational therapeutic candidate that has not yet been approved by any regulatory authority and its safety and effectiveness have not been established.

About Cutaneous Lupus Erythematosus (CLE)

CLE, a type of lupus, is a serious chronic autoimmune skin disease that can occur with or without systemic manifestations; people with CLE frequently experience symptoms including rash, pain, itch and photosensitivity as well as skin damage that may worsen over time and can include irreversible scarring, alopecia and dyspigmentation that can be disfiguring and substantially impact quality of life.^3-6 Currently, there are no approved targeted therapies for CLE and the last drug was approved in the 1950s.

About Biogen

Founded in 1978, Biogen is a leading biotechnology company that pioneers innovative science to deliver new medicines to transform patients’ lives and to create value for shareholders and our communities. We apply deep understanding of human biology and leverage different modalities to advance first-in-class treatments or therapies that deliver superior outcomes. Our approach is to take bold risks, balanced with return on investment to deliver long-term growth.

We routinely post information that may be important to investors on our website at www.biogen.com. Follow us on social media – Facebook, LinkedIn, X, YouTube.

Biogen Safe Harbor

This news release contains forward-looking statements, including: the potential clinical effects of litifilimab; the potential of litifilimab to improve the health, wellbeing and outcomes for patients with CLE; the potential benefits, safety and efficacy of litifilimab; potential regulatory discussions, submissions and approvals and the timing thereof; potential therapeutic options for the treatment of CLE; the potential of Biogen’s commercial business and pipeline programs, including litifilimab; and risks and uncertainties associated with drug development and commercialization. These forward-looking statements may be accompanied by such words as “aim,” “anticipate,” “assume,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “forecast,” “goal,” “guidance,” “hope,” “intend,” “may,” “objective,” “outlook,” “plan,” “possible,” “potential,” “predict,” “project,” “prospect,” “should,” “target,” “will,” “would” or the negative of these words or other words and terms of similar meaning. Drug development and commercialization involve a high degree of risk, and only a small number of research and development programs result in commercialization of a product. Results in early-stage clinical trials may not be indicative of full results or results from later stage or larger scale clinical trials and do not ensure regulatory approval. You should not place undue reliance on these statements. Given their forward-looking nature, these statements involve substantial risks and uncertainties that may be based on inaccurate assumptions and could cause actual results to differ materially from those reflected in such statements.

These forward-looking statements are based on management’s current beliefs and assumptions and on information currently available to management. Given their nature, we cannot assure that any outcome expressed in these forward-looking statements will be realized in whole or in part. We caution that these statements are subject to risks and uncertainties, many of which are outside of our control and could cause future events or results to differ materially from those stated or implied in this document, including, among others, uncertainty of our long-term success in developing, licensing, or acquiring other product candidates or additional indications for existing products; expectations, plans, prospects and timing of actions relating to product approvals, approvals of additional indications for our existing products, sales, pricing, growth, reimbursement and launch of our marketed and pipeline products; the potential impact of increased product competition in the biopharmaceutical and healthcare industry, as well as any other markets in which we compete, including increased competition from new originator therapies, generics, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways; our ability to effectively implement our corporate strategy; difficulties in obtaining and maintaining adequate coverage, pricing, and reimbursement for our products; the drivers for growing our business, including our dependence on collaborators and other third parties for the development, regulatory approval, and commercialization of products and other aspects of our business, which are outside of our full control; risks related to commercialization of biosimilars, which is subject to such risks related to our reliance on third-parties, intellectual property, competitive and market challenges and regulatory compliance; the risk that positive results in a clinical trial may not be replicated in subsequent or confirmatory trials or success in early stage clinical trials may not be predictive of results in later stage or large scale clinical trials or trials in other potential indications; risks associated with clinical trials, including our ability to adequately manage clinical activities, unexpected concerns that may arise from additional data or analysis obtained during clinical trials, regulatory authorities may require additional information or further studies, or may fail to approve or may delay approval of our drug candidates; and the occurrence of adverse safety events, restrictions on use with our products, or product liability claims; and any other risks and uncertainties that are described in other reports we have filed with the U.S. Securities and Exchange Commission, which are available on the SEC’s website at www.sec.gov. 

These statements speak only as of the date of this press release and are based on information and estimates available to us at this time. Should known or unknown risks or uncertainties materialize or should underlying assumptions prove inaccurate, actual results could vary materially from past results and those anticipated, estimated or projected. Investors are cautioned not to put undue reliance on forward-looking statements. A further list and description of risks, uncertainties and other matters can be found in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025and in our subsequent reports on Form 10-Q. Except as required by law, we do not undertake any obligation to publicly update any forward-looking statements whether as a result of any new information, future events, changed circumstances or otherwise.

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References:

1. Furie R, Werth VP, Merola JF, et al. Monoclonal antibody targeting BDCA2 ameliorates skin lesions in systemic lupus erythematosus. J Clin Invest. 2019;129(3):1359-1371. doi:10.1172/JCI124466
2. Pellerin A, Otero K, Czerkowicz JM, et al. Anti-BDCA2 monoclonal antibody inhibits plasmacytoid dendritic cell activation through Fc-dependent and Fc-independent mechanisms. EMBO Mol Med. 2015;7(4):464-476. doi:10.15252/emmm.201404719
3. Drenkard C, Barbour KE, Greenlund KJ, Lim SS. The Burden of Living With Cutaneous Lupus Erythematosus. Front Med (Lausanne). 2022 Aug 8;9:897987. doi: 10.3389/fmed.2022.897987. PMID: 36017007; PMCID: PMC9395260.
4. Ogunsanya ME, Brown CM, Lin D, et al (2018). Understanding the disease burden and unmet needs among patients with cutaneous lupus erythematosus: A qualitative study. Int J Womens Dermatol. 4(3):152-158.
5. Ogunsanya ME, Cho SK, Hudson A, Chong, BF (2019). Validation and reliability of a disease-specific quality of life measure in patients with cutaneous lupus erythematosus. Br J Dermatol. 180(6):1430-1437.
6. Drenkard C, Parker S, Aspey LD, Gordon C, Helmick CG, Bao G, Lim SS. Racial Disparities in the Incidence of Primary Chronic Cutaneous Lupus Erythematosus in the Southeastern US: The Georgia Lupus Registry. Arthritis Care Res (Hoboken). 2019 Jan;71(1):95-103. doi: 10.1002/acr.23578. PMID: 29669194; PMCID: PMC6193862.