Jade Biosciences Introduces JADE201, An Investigational Half-Life Extended Afucosylated Monoclonal Antibody Targeting BAFF Receptor To Treat Autoimmune Disorders

Jade Biosciences, Inc., a clinical-stage biotechnology company focused on developing advanced therapies for autoimmune diseases, has announced the introduction of JADE201, an investigational half-life extended, afucosylated monoclonal antibody that targets the B-cell activating factor receptor (BAFF-R). The therapy has been designed to address the limitations of existing B cell-directed treatments by combining a dual mechanism of action with half-life extension technology. The goal is to provide stronger, longer-lasting efficacy and improve the clinical benefits of B-cell depleting therapies for a broad range of autoimmune disorders.

According to Tom Frohlich, Chief Executive Officer of Jade, the launch of JADE201 marks a significant step forward in the company’s mission to build a complementary portfolio of therapies that modulate B-cell biology. He stated that JADE201 enhances Jade’s existing autoimmune pipeline, which also includes JADE101, a potentially best-in-class anti-APRIL monoclonal antibody being developed for the treatment of IgA nephropathy. Frohlich explained that JADE201 combines a proven mechanism of action with half-life extension, designed to provide potent and durable activity while offering patients the advantage of less frequent dosing. With a world-class development team and a strengthened financial position following recent private financing, Jade Biosciences is well-equipped to advance new standards of care for autoimmune diseases.

Andrew King, Chief Scientific Officer and Head of Research and Development at Jade, highlighted the scientific foundation behind JADE201. He noted that the new therapy builds on the clinical validation of targeting BAFF-R, a pathway already shown to play a key role in autoimmune disease mechanisms. JADE201 utilizes a dual mechanism of action that enhances B-cell depletion through antibody-dependent cellular cytotoxicity (ADCC) while simultaneously blocking BAFF-R-mediated survival and activation signals. This dual approach is expected to deliver deeper and more sustained B-cell depletion with less frequent subcutaneous dosing, offering a differentiated treatment option across multiple autoimmune diseases.

Current B-cell depleting therapies often have limitations, as they may spare certain pathogenic B-cell populations, leading to the risk of relapse and resistance. These issues are frequently linked to elevated BAFF signaling, which promotes B-cell repopulation and autoimmunity. JADE201 was specifically engineered to overcome these challenges. 

It has been developed with a high binding affinity to BAFF-R, ensuring robust receptor engagement across multiple B-cell subsets. The molecule incorporates afucosylation to enhance ADCC and includes a clinically validated Fc mutation to improve neonatal Fc receptor (FcRn) binding. This design aims to extend systemic exposure while maintaining therapeutic activity, ultimately reducing treatment frequency without compromising efficacy.

The proof of concept for BAFF-R inhibition has already been demonstrated through ianalumab, which has shown efficacy across several autoimmune indications, including multiple positive Phase 3 clinical trials. JADE201 builds upon the pharmacological strengths of ianalumab while addressing one of its key limitations—a relatively short human half-life. By integrating half-life extension technology, JADE201 is expected to provide prolonged drug exposure, enabling less frequent subcutaneous dosing and potentially improving overall efficacy and patient convenience.

In non-human primate studies, JADE201 demonstrated promising preclinical results. It achieved dose-dependent BAFF-R receptor occupancy and sustained B-cell depletion following a single subcutaneous dose. Moreover, it exhibited approximately a two-fold increase in half-life compared with ianalumab. This extended exposure supports the potential for improved treatment durability and reduced dosing frequency, which may lessen the treatment burden on patients while maintaining potency.

Jade Biosciences plans to initiate a first-in-human clinical study of JADE201 in patients with rheumatoid arthritis during the first half of 2026. This will be a randomized, placebo-controlled, single ascending dose trial designed to evaluate safety, tolerability, pharmacokinetics, and pharmacodynamics. The study will also include biomarker-rich endpoints, such as BAFF-R occupancy, soluble BAFF levels, and detailed B-cell subpopulation profiling, to better understand the therapy’s biological effects and potential clinical advantages.

Through the development of JADE201, Jade Biosciences continues to demonstrate its commitment to advancing innovative, science-driven therapies for autoimmune diseases. By leveraging cutting-edge antibody engineering and clinical validation, the company aims to deliver treatments that are not only more effective but also more convenient and sustainable for patients in need.