Jade Biosciences Announces Preclinical Data Characterizing JADE301, a Potentially Best-in-Class, Half-Life-Extended Anti-IFN-β Monoclonal Antibody in Development for Dermatomyositis, at EADV 2026

• JADE301 is designed to build on a clinically validated IFN-β mechanism with a differentiated profile designed for infrequent subcutaneous dosing
  
• JADE301 demonstrated high-affinity, selective IFN-β binding and greater functional potency than a dazukibart comparator in disease-relevant human cells
  
• Following subcutaneous administration in non-human primates, JADE301 was effectively half-life extended with an approximately 25-day half-life and predictable distribution into muscle
  
• JADE301 was well tolerated in non-human primates at all evaluated subcutaneous doses
  
• Phase 1 healthy volunteer trial expected to begin in the fourth quarter of 2026; interim data anticipated in the second half of 2027
  
• Company to host conference call and webcast today at 8:30 a.m. ET
  

SAN FRANCISCO and VANCOUVER, British Columbia, Sept. 30, 2026 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (“Jade” or the “Company”) (Nasdaq: JBIO), a clinical-stage biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced preclinical data characterizing JADE301, its potentially best-in-class, half-life-extended anti-interferon beta (IFN-β) monoclonal antibody in development for dermatomyositis (DM), a rare, chronic and debilitating autoimmune disease characterized by painful inflammatory skin disease and progressive muscle weakness. JADE301 is a fully human IgG1 monoclonal antibody with a YTE modification designed to selectively and potently neutralize IFN-β and inhibit downstream signaling implicated as a proximal driver in DM pathogenesis.

The data are being presented in an e-poster at the 2026 European Academy of Dermatology and Venereology (EADV) Congress in Vienna, Austria (Poster #P1813).

“JADE301 was designed to leverage the clinically validated anti-IFN-β mechanism in dermatomyositis with a differentiated molecular and pharmacokinetic profile,” said Andrew King, Ph.D., President, Research & Development of Jade Biosciences. “These preclinical data support potent and selective IFN-β inhibition, and demonstrate pharmacokinetic properties characterized by an extended half-life, favorable subcutaneous bioavailability, and muscle distribution. These attributes support the development of a targeted, disease-modifying therapy that has the potential to provide durable improvement across both skin and muscle manifestations of dermatomyositis, while reducing treatment burden for patients through infrequent subcutaneous dosing.”

“For people living with dermatomyositis, the treatment goal is to control both skin and muscle disease activity, restore strength and daily function, and limit reliance on chronic steroids,” said Rohit Aggarwal, M.D., M.S., Professor of Medicine at University of Pittsburgh and Medical Director of Arthritis and Autoimmunity Center at University of Pittsburgh Medical Center. “Yet targeted treatment options remain limited, and many patients continue to experience substantial disease and treatment burden. The clinical validation of IFN-β as a therapeutic target represents a promising advance for the field. JADE301’s preclinical profile, including potent and selective IFN-β neutralization, extended half-life, and subcutaneous administration, supports clinical evaluation to assess if this approach can deliver durable disease control with a less burdensome treatment regimen.”

Summary of JADE301 Preclinical Data

High-affinity, selective and potent IFN-β neutralization

• JADE301 demonstrated high-affinity binding to IFN-β, with a K_D of 11.3 pM, approximately 2.5-fold higher affinity than a dazukibart comparator, and no detectable binding to other interferon family proteins.
• JADE301 potently inhibited downstream IFN-β signaling.
  • In a human immune cell line, JADE301 inhibited induction of pSTAT with an IC₅₀ of 13 pM, approximately 2.5-fold more potent than the dazukibart comparator.
  • Suppression of MX-1, a marker of IFN pathway activity relevant to DM, was demonstrated in human dermal fibroblasts, a disease-relevant skin cell type, and peripheral blood mononuclear cells; in human dermal fibroblasts, JADE301 inhibited MX-1 induction with an IC₅₀ of 11 pM, approximately 8-fold more potent than the dazukibart comparator.

Differentiated pharmacokinetic profile supports potential for infrequent subcutaneous dosing

• JADE301 demonstrated an approximately 30-day half-life following a 30 mg/kg intravenous dose in non-human primates (NHPs), approximately 3-fold longer than the dazukibart comparator.
• Following subcutaneous (SC) administration in NHPs, JADE301 demonstrated an approximately 25-day half-life. Translational modeling predicted human SC bioavailability of approximately 73%–75%, compared with a reported dazukibart SC bioavailability in humans of approximately 43%–44%, supporting the potential for convenient, infrequent SC dosing.
• JADE301 concentrations in muscle were consistent with the typical range reported for monoclonal antibodies, approximately 1%–4% of serum concentrations, providing a translational framework to inform dose selection and exposure at a key site of active disease in DM.
  

Favorable nonclinical tolerability profile

• In a GLP toxicology study in NHPs, subcutaneous JADE301 was administered every two weeks at doses of 0, 50, 100 and 200 mg/kg and was well tolerated at all dose levels evaluated.
• There were no treatment-related adverse clinical observations or meaningful adverse findings on laboratory or other standard safety assessments. No treatment-related histopathology findings were observed.

JADE301 Phase 1 Development

Jade expects to initiate a placebo-controlled, single ascending-dose Phase 1 trial evaluating subcutaneous JADE301 in 24 healthy volunteers in the fourth quarter of 2026, with interim data anticipated in the second half of 2027. The study is designed to assess safety and tolerability, and to characterize the pharmacokinetic and immunogenicity profile of JADE301.

Conference Call and Webcast

Jade will host a conference call and webcast today, September 30, 2026, at 8:30 a.m. ET to discuss the JADE301 profile outlined in this press release. Investors and the general public are invited to listen to the live webcast and may register on the “Events and Presentations” page of the company’s website at JadeBiosciences.com. To join the live conference call, participants must register here. Upon registering, you will receive dial-in details and a unique PIN to access the call. A replay of the webcast will be available for 90 days on the Jade website. 
About Dermatomyositis

Dermatomyositis (DM) is a rare, chronic autoimmune disease affecting approximately 50,000 adults in the U.S. and characterized by inflammatory skin disease, progressive muscle weakness and potentially serious systemic complications. Excessive type I interferon signaling is a hallmark of DM, with IFN-β believed to play a central role in driving inflammation in both skin and muscle. DM can substantially impair daily functioning, including the ability to walk, climb stairs, bend or lift, while painful skin disease and severe itching can further disrupt sleep and quality of life. Many patients continue to experience chronic disease activity despite treatment, underscoring the need for more effective, durable and less burdensome treatment options.

About JADE301

JADE301 is an investigational anti-IFN-β monoclonal antibody being developed for dermatomyositis. By selectively neutralizing IFN-β, a clinically validated target and key driver of disease pathology, JADE301 is designed to address both skin and muscle manifestations of DM. Engineered with half-life extension technology, JADE301 is being developed with the goal of delivering a convenient, infrequent subcutaneous administration, with the potential to provide durable disease control and reduce treatment burden.

About Jade Biosciences, Inc.

Jade Biosciences is a clinical-stage biotechnology company focused on developing best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently being evaluated for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE301, an anti-IFN-β monoclonal antibody. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn.

Forward-Looking Statements

Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation: Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, JADE201 and JADE301 and their best-in-class potential; the expected timelines for the initiation of, and the availability of interim data from, the Phase 1 clinical trial of JADE301; the projected human bioavailability of JADE301; and the potential therapeutic uses, efficacy, durability, safety profiles, and dosing of JADE301. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to: the planned clinical trial of JADE301 and any other clinical trials may be delayed or may not demonstrate desirable efficacy or predicted performance; adverse events and safety signals may occur; modeled and predicted data may not be realized in actual clinical studies; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may be delayed to a point where they are not commercially viable; clinical trial start up, enrollment or regulatory challenges may occur; challenges associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of its product candidates may occur; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the Quarterly Report on Form 10-Q for the quarter ended June 30, 2026). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements, except as required by law. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade.

Jade Biosciences Contact

Zane Goodwin
IR@JadeBiosciences.com
Media@JadeBiosciences.com