Jade Biosciences Initiates First-in-Human Phase 1 Trial of BAFF-R Antibody JADE201

Jade Biosciences announced that the first participant has been dosed in a first-in-human Phase 1 clinical trial evaluating JADE201, an investigational half-life extended afucosylated monoclonal antibody targeting the B cell activating factor receptor (BAFF-R) for autoimmune diseases.¹

According to the company, the randomized, placebo-controlled study is evaluating single ascending doses of JADE201 in patients with rheumatoid arthritis (RA) and is designed to assess safety, tolerability, pharmacokinetics, and pharmacodynamics.¹ Interim Phase 1 data are expected in 2027 and may help inform indication prioritization across multiple autoimmune diseases supported by BAFF-R biology.¹

How could BAFF-R targeting expand autoimmune disease treatment options?

JADE201 was engineered to deplete B cells through what the company describes as a dual mechanism of action involving enhanced antibody effector function and blockade of BAFF signaling pathways.¹ BAFF-R signaling has been associated with B-cell survival, activation, and autoreactivity in several autoimmune conditions.²

The investigational therapy also incorporates afucosylation technology designed to enhance antibody-dependent cellular cytotoxicity, alongside half-life extension modifications intended to support less frequent dosing schedules.³

“By integrating enhanced effector function and extended receptor occupancy, JADE201 aims to improve both the depth and durability of response across a range of autoimmune diseases,” the company stated in the press release.¹

Preclinical studies in non-human primates demonstrated dose-dependent BAFF-R occupancy, sustained B-cell depletion, and an extended half-life compared with earlier-generation BAFF-R-directed antibodies, according to the company.^1,3

The Phase 1 study will also evaluate biomarker endpoints, including BAFF-R occupancy, soluble BAFF levels, and B-cell profiling.¹

Why is BAFF-R emerging as a target in autoimmune disease research?

B-cell-directed therapies continue to attract attention across autoimmune disease development programs because of the central role B cells play in antibody production and inflammatory signaling.²

Clinical proof-of-concept for BAFF-R inhibition has previously been demonstrated with other investigational therapies in autoimmune disorders, including systemic lupus erythematosus and Sjögren’s disease.³

Andrew King, chief scientific officer and head of research and development at Jade Biosciences, previously stated that JADE201 was designed to potentially improve durability and convenience compared with existing BAFF-R-targeting approaches.³

Jade Biosciences said the company is developing a broader pipeline of autoimmune disease therapies, including JADE101, an anti-APRIL monoclonal antibody currently in clinical development for immunoglobulin A nephropathy.^1,4

References

1. Jade Biosciences Announces First Participant Dosed in First-in-Human Phase 1 Clinical Trial of JADE201. (2026 May 26). Jade Biosciences. Accessed May 27, 2026. https://www.globenewswire.com/news-release/2026/05/26/3301441/0/en/jade-biosciences-announces-first-participant-dosed-in-first-in-human-phase-1-clinical-trial-of-jade201-a-novel-half-life-extended-afucosylated-anti-baff-receptor-monoclonal-antibod.html
2. Mackay F, Schneider P. (2009 Jul). Cracking the BAFF code. Nat Rev Immunol. https://pubmed.ncbi.nlm.nih.gov/19521398/
3. Jade Biosciences Announces JADE201, a Potentially Best-in-Class Half-Life Extended Afucosylated Anti-BAFF Receptor Monoclonal Antibody in Development for Autoimmune Diseases. ( 2025 Oct 7). Jade Biosciences. Accessed May 27, 2026. https://www.biospace.com/press-releases/jade-biosciences-announces-jade201-a-potentially-best-in-class-half-life-extended-afucosylated-anti-baff-receptor-monoclonal-antibody-in-development-for-autoimmune-diseases
4. Jade Biosciences Announces First Cohort Dosed in Phase 1 Healthy Volunteer Clinical Trial of JADE101. (2025 Sep 2). Jade Biosciences. Accessed May 27, 2026. https://jadebiosciences.com/press-release/jade-biosciences-announces-first-cohort-dosed-in-phase-1-healthy-volunteer-clinical-trial-of-jade101-a-novel-and-potentially-best-in-class-anti-april-monoclonal-antibody-being-evaluated-for-the-treat