Biogen to Present New Late-Breaking Litifilimab Phase 2 AMETHYST Data in Cutaneous Lupus Erythematosus at 2026 American Academy of Dermatology Annual Meeting

Rhea-AI Summary

Biogen (Nasdaq: BIIB) will present late-breaking Phase 2 AMETHYST Part A data on litifilimab in cutaneous lupus erythematosus (CLE) at the 2026 American Academy of Dermatology Annual Meeting, March 27-31.

Presentations include a late-breaking oral on March 28 and posters on CLASI and CLA-IGA-R measures. Litifilimab, a BDCA2-targeting monoclonal antibody, recently received FDA Breakthrough Therapy Designation for CLE, supported by AMETHYST Part A and prior LILAC results. Phase 3 is on track with a planned data readout in 2027.

Positive

• FDA Breakthrough Therapy designation for litifilimab in CLE
• Phase 2 AMETHYST Part A showed safety and efficacy signals in CLE
• Phase 3 study on track with a 2027 data readout

Negative

• Clinical evidence currently limited to Phase 2 results rather than pivotal Phase 3 data
• Readout uncertainty: Phase 3 data not available until 2027, leaving near-term regulatory and commercial outcomes unresolved

News Market Reaction – BIIB

+0.60%

1 alert

+0.60% News Effect

On the day this news was published, BIIB gained 0.60%, reflecting a mild positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

AMETHYST Part A phase: Phase 2 AMETHYST study design: Phase 2/3 AMETHYST Part A duration: 24-week results +5 more

8 metrics

AMETHYST Part A phase Phase 2 Part A of AMETHYST Phase 2/3 CLE study

AMETHYST study design Phase 2/3 AMETHYST study of litifilimab in CLE

AMETHYST Part A duration 24-week results Efficacy and safety results presented at AAD

AAD 2026 dates March 27–31, 2026 American Academy of Dermatology Annual Meeting window

Litifilimab oral session time 3:24 PM MT / 5:24 PM ET Late-breaking AMETHYST Part A oral presentation on March 28

Late-breaking abstract ID #79781 AMETHYST Part A efficacy and safety oral presentation

Poster ID #71096 CLA-IGA-R content validity qualitative study poster

Poster ID #75155 Correlation between CLASI and CLA-IGA-R poster

Market Reality Check

Price: $183.43 Vol: Volume 841,689 is at 0.94...

normal vol

$183.43 Last Close

Volume Volume 841,689 is at 0.94x the 20-day average, indicating typical trading activity pre-announcement. normal

Technical Price 182.31 is trading above the 200-day MA at 156.36, suggesting a pre-news uptrend versus longer-term levels.

Peers on Argus

Momentum scanner shows only SNY with notable activity, up 1.81% without related ...

1 Up

Momentum scanner shows only SNY with notable activity, up 1.81% without related news. Broader large-cap pharma peers show mixed, modest moves, suggesting this CLE update is company-specific rather than a sector-wide driver.

Previous Clinical trial Reports

5 past events · Latest: Jan 11 (Neutral)

Same Type Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Jan 11	Dravet Phase 3 timelines	Neutral	-1.1%	Updated enrollment and readout timelines for EMPEROR zorevunersen Phase 3 study.
Dec 22	QALSODY long-term data	Positive	-0.1%	Publication of Phase 3 VALOR and extension results for QALSODY in SOD1-ALS.
Nov 25	LEQEMBI sBLA completion	Positive	+2.9%	Completion of rolling sBLA for LEQEMBI IQLIK subcutaneous starting dose.
Sep 02	LEQEMBI sBLA initiation	Positive	+1.4%	Initiation of rolling sBLA for LEQEMBI IQLIK SC autoinjector formulation.
Aug 25	Zorevunersen data presentations	Positive	-2.1%	New 3-year zorevunersen data and EMPEROR Phase 3 support in Dravet syndrome.

Pattern Detected

Clinical-trial-related news for Biogen and partners has produced generally modest, mixed price reactions, with both gains and declines following positive updates.

Recent Company History

Recent history shows Biogen frequently in clinical development headlines, often with partners. Prior clinical-trial-tagged events included zorevunersen timeline updates, long-term QALSODY data in SOD1-ALS, and multiple LEQEMBI IQLIK filings and data disclosures between Aug 25, 2025 and Jan 11, 2026. Reactions around these updates were small (average move about 0.22%) and mixed in direction, indicating that even meaningful clinical data often translated into only modest near-term share moves.

Historical Comparison

+0.2% avg move · Past clinical-trial headlines involving Biogen and partners led to small, mixed stock moves, averagi...

clinical trial

+0.2%

Average Historical Move clinical trial

Past clinical-trial headlines involving Biogen and partners led to small, mixed stock moves, averaging about 0.22%, suggesting limited but variable near-term price impact from similar updates.

Clinical news flow shows progression from early- to late-stage programs across neurology, including zorevunersen Phase 3 development and formulation advances for LEQEMBI.

Market Pulse Summary

This announcement highlights late-breaking Phase 2 AMETHYST data for litifilimab in cutaneous lupus ...

Analysis

This announcement highlights late-breaking Phase 2 AMETHYST data for litifilimab in cutaneous lupus erythematosus, supported by FDA Breakthrough Therapy Designation and prior LILAC results. It extends Biogen’s track record of regular clinical updates, where past trial news produced modest average moves of about 0.22%. Investors may focus on how these CLE findings translate into the ongoing Phase 3 portion, as well as parallel neurology programs and upcoming regulatory milestones.

Key Terms

cutaneous lupus erythematosus, breakthrough therapy designation, monoclonal antibody, mab, +4 more

8 terms

cutaneous lupus erythematosus medical

"showing safety and efficacy of litifilimab in cutaneous lupus erythematosus (CLE)"

Cutaneous lupus erythematosus is an autoimmune skin condition in which the body's defense system mistakenly attacks skin, causing rashes, sores or scarring that can be persistent or recurrent; think of it as a security system that misidentifies the skin as a threat. It matters to investors because its chronic nature, need for long‑term treatment, and regulatory hurdles shape demand for therapies, clinical trial designs, approval timelines and potential healthcare costs in the dermatology and specialty drug markets.

breakthrough therapy designation regulatory

"Litifilimab was recently granted Breakthrough Therapy Designation by the FDA for CLE"

A breakthrough therapy designation is a regulatory fast-track given to a drug or treatment that shows early signs of providing a major improvement over existing options for a serious condition. Think of it as a VIP lane that can speed up development and more intensive guidance from regulators, which matters to investors because it can shorten time to market, reduce development risk and potentially increase a company’s value — though it does not guarantee approval.

monoclonal antibody medical

"Litifilimab is a potential first in-class, monoclonal antibody (mAb) targeting blood"

A monoclonal antibody is a laboratory-made protein designed to recognize and attach to a specific target in the body, such as a disease-causing substance or cell. It functions like a highly precise lock-and-key tool, helping to treat or detect illnesses. For investors, companies developing monoclonal antibodies can represent promising opportunities in the healthcare sector, especially as these treatments often address unmet medical needs.

mab medical

"first in-class, monoclonal antibody (mAb) targeting blood dendritic cell antigen 2"

A mAb (monoclonal antibody) is a lab-made protein designed to recognize and bind a specific target on cells or pathogens, like a custom-made key that fits one lock. Investors care because mAbs are often developed as therapies or diagnostic tools whose clinical trial results, regulatory approvals, production capacity, and patent status can drive significant revenue swings and affect a company’s valuation and risk profile.

bdca2 medical

"monoclonal antibody (mAb) targeting blood dendritic cell antigen 2 (BDCA2)"

BDCA2 is a protein found on the surface of a specialized immune cell called a plasmacytoid dendritic cell; it acts like a light switch that helps control those cells’ activity, especially their production of immune-signaling molecules. For investors, BDCA2 matters because drugs or antibodies that target it can change immune responses and are being developed as treatments for autoimmune and inflammatory diseases, so breakthroughs or setbacks can affect the commercial prospects and risks of companies working in that space.

phase 2 medical

"Late-breaking AMETHYST Part A study results to be presented, showing safety and efficacy... Phase 2 AMETHYST"

Phase 2 is the mid-stage clinical trial where a new drug or treatment is tested in a larger group of patients to see if it works and to keep checking safety after initial human testing. Think of it as a field test that proves whether a product actually delivers its promised benefit. Investors watch Phase 2 closely because its results strongly influence a medicine’s chances of reaching the market, the size of its potential sales, and the company’s valuation.

phase 3 medical

"The Phase 3 part of the study, which will further evaluate litifilimab in CLE"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

investigator’s global assessment medical

"Content Validity of the Cutaneous Lupus Activity Investigator’s Global Assessment―Revised (CLA-IGA-R)"

A clinician’s overall rating of a patient’s condition or how well a treatment is working during a clinical trial, usually expressed on a simple scale (for example: clear, mild, moderate, severe). Think of it as a coach giving a single score that sums up a player’s performance rather than listing every statistic. Investors watch this measure because it is often used as an official trial endpoint that can drive regulatory decisions, market expectations, and a drug’s commercial prospects.

AI-generated analysis. Not financial advice.

• Late-breaking AMETHYST Part A study results to be presented, showing safety and efficacy of litifilimab in cutaneous lupus erythematosus (CLE)
• Litifilimab was recently granted Breakthrough Therapy Designation by the FDA for CLE; AMETHYST Part A results supported the designation
• CLE is a serious autoimmune disease that impacts the daily lives of patients and can lead to permanent scarring and disfigurement when left untreated, and has no targeted treatment option
  

CAMBRIDGE, Mass., March 19, 2026 (GLOBE NEWSWIRE) -- Biogen Inc. (Nasdaq: BIIB) today announced upcoming scientific presentations at the 2026 American Academy of Dermatology (AAD) Annual Meeting, taking place March 27-31. Late-breaking data from Part A (Phase 2) of the AMETHYST Phase 2/3 study will be presented that highlight litifilimab’s effect on cutaneous lupus erythematosus (CLE) disease activity. Litifilimab is a potential first in-class, monoclonal antibody (mAb) targeting blood dendritic cell antigen 2 (BDCA2) and was the first investigational therapy to show positive results in CLE, as shown in the Phase 2 LILAC study. Additional presentations at AAD will provide new insights into measures used to assess the severity of CLE disease activity in both clinical trials and clinical practice.

“The data we are presenting at AAD reflect Biogen’s decades of investment in cutaneous lupus, a disease that extends far beyond the skin, significantly impacting the daily lives and mental health of people living with this disease, and often leading to permanent scarring,” said Diana Gallagher, MD, Senior Vice President and Head of AD, MS and Immunology Development Units at Biogen. “We look forward to sharing the Phase 2 results from AMETHYST that show the potential of litifilimab in CLE. The Phase 3 part of the study, which will further evaluate litifilimab in CLE, is on track and a data readout is expected in 2027.”

Earlier this year, the U.S. Food and Drug Administration granted litifilimab Breakthrough Therapy Designation for CLE. Results from the Phase 2 (Part A) part of the AMETHYST study supported the designation, in addition to the previously presented Phase 2 LILAC study results.

Details of the presentations at AAD are as follows:

Late-Breaking Oral Presentation

• “Efficacy and Safety of Litifilimab in Cutaneous Lupus Erythematosus (CLE): 24-week results of the Phase 2 Study, AMETHYST Part A” to be presented Saturday, March 28 3:24 PM MT / 5:24 PM ET in Bellco Theatre 3; #79781
  

Key Posters

• “A Qualitative Study to Support the Content Validity of the Cutaneous Lupus Activity Investigator’s Global Assessment―Revised (CLA-IGA-R): Clinician Perspectives” on display throughout meeting in Poster Exhibits Center; #71096
• “Correlation Between CLASI and CLA-IGA-R Among Patients With CLE in a Multi-Center Cross-Sectional Study in the US” on display throughout meeting in Poster Exhibits Center; #75155

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 patient’s 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, 2024 and 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.

Digital Media Disclosure
From time to time we have used, or expect in the future to use, our investor relations website (investors.biogen.com), the Biogen LinkedIn account (linkedin.com/company/biogen-) and the Biogen X account (https://x.com/biogen) as a means of disclosing information to the public in a broad, non-exclusionary manner, including for purposes of the SEC’s Regulation Fair Disclosure (Reg FD). Accordingly, investors should monitor our investor relations website and this social media channel in addition to our press releases, SEC filings, public conference calls and webcasts, as the information posted on them could be material to investors.

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.

MEDIA CONTACT: Biogen Madeleine Shin + 1 781 464 3260 public.affairs@biogen.com	INVESTOR CONTACT: Biogen Tim Power + 1 781 464 2442 IR@biogen.com

FAQ

What Phase 2 AMETHYST Part A litifilimab data will Biogen (BIIB) present at AAD 2026?

Biogen will present 24-week Phase 2 AMETHYST Part A results showing litifilimab safety and efficacy in CLE. According to the company, the late-breaking oral presentation on March 28 highlights disease activity improvements and safety findings supporting the Breakthrough Therapy Designation.

When and where will Biogen (BIIB) present the late-breaking AMETHYST data at the AAD 2026 meeting?

The late-breaking oral presentation is scheduled for March 28 at 3:24 PM MT / 5:24 PM ET in Bellco Theatre 3. According to the company, poster exhibits on CLASI and CLA-IGA-R will be displayed throughout the meeting, March 27-31.

What is the regulatory status of litifilimab for cutaneous lupus erythematosus (CLE) announced by Biogen (BIIB)?

Litifilimab has received FDA Breakthrough Therapy Designation for CLE. According to the company, AMETHYST Part A and prior LILAC Phase 2 results supported the Breakthrough designation and accelerated development focus.

How does the AMETHYST Phase 3 timeline affect investors in Biogen (BIIB)?

Phase 3 is ongoing with a data readout expected in 2027, delaying pivotal clarity until then. According to the company, the Phase 3 part remains on track, so regulatory and commercial outcomes will depend on that future readout.

What measures related to CLE severity will Biogen (BIIB) discuss at AAD 2026 besides AMETHYST results?

Biogen will present posters on CLA-IGA-R content validity and its correlation with CLASI in CLE. According to the company, these analyses aim to refine clinical trial and clinical-practice assessments of disease activity.