Sibeprenlimab

Preclinical data highlighted JADE101’s femtomolar APRIL binding affinity, extended non-human primate half-life of approximately 27 days, and sustained IgA suppression In non-human primates, JADE101 showed a differentiated pharmacokinetic and pharmacodynamic profile with deep and sustained IgA reductions and the potential to support convenient subcutaneous dosing every eight weeks or longer First-in-human trial expected to begin second half 2025; biomarker-rich interim data in healthy volunteers expected first-half 2026 to inform patient dose and schedule Company to host conference call and webcast today, June 9, 2025, at 8:00 a.m. ET SAN FRANCISCO, CA, USA and VANCOUVER, Canada I June 09, 2025 I Jade Biosciences, Inc. (“Jade”) (Nasdaq: JBIO), a biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced a detailed preclinical characterization of JADE101, its anti-A Proliferation-Inducing Ligand (APRIL) monoclonal antibody, in development for IgA nephropathy (IgAN), a chronic autoimmune kidney disease. The findings, presented during an oral session at the 62nd European Renal Association (ERA) Congress, support advancement of JADE101 into a planned healthy volunteer study in the second half of 2025. “IgA nephropathy often begins in young adulthood and typically requires lifelong treatment, yet current treatment options have limitations in efficacy and ease of use,” said Andrew King, BVMS, Ph.D., Chief Scientific Officer and Head of R&D at Jade Biosciences. “Jade’s preclinical data presented at ERA demonstrate JADE101’s potential to be a best-in-class disease-modifying therapy. JADE101 has the potential to fully capture the efficacy available to the anti-APRIL mechanism with convenient, infrequent dosing. We believe this profile could translate into meaningful long-term benefit for patients, and we look forward to advancing this promising candidate into the clinic later this year.” Summary of Jade Biosciences’ ERA 2025 Presentation Jade’s presentation at ERA focused on a comprehensive preclinical characterization of JADE101, a fully human monoclonal antibody targeting APRIL, designed to address key limitations of earlier molecules in this class. JADE101 incorporates a YTE-modified IgG1 backbone and was engineered to improve target affinity, extend pharmacokinetic exposure, and reduce risks associated with immune complex formation and rapid clearance. The molecular design of JADE101 prolonged systemic exposure that delivers sustained target engagement, with a goal of supporting clinical dosing intervals of eight weeks or potentially longer. JADE101 was compared with sibeprenlimab, an investigational late-stage anti-APRIL monoclonal antibody, manufactured from publicly available sequences. A YTE-engineered version of sibeprenlimab was also tested to isolate the impact of Fc modification on pharmacokinetic profiles in non-human primates (NHPs). Key findings included: Jade plans to initiate a study of JADE101 in healthy volunteers in the second half of 2025. The study will evaluate safety, tolerability, pharmacokinetics, pharmacodynamics, and suppression of key biomarkers including APRIL and IgA. Interim data are expected in the first half of 2026 and are anticipated to guide dose and dose interval selection for future JADE101 studies in patients with IgAN. Conference Call and Webcast Jade Biosciences will host a conference call and webcast today, Monday, June 9, 2025, at 8:00 a.m. ET to review the JADE101 data presented at ERA 2025. Investors and the public are invited to join the live webcast by registering on the “Events and Presentations” page of JadeBiosciences.com . To join the conference call, participants must register here . Upon registering, dial-in details and a unique PIN will be provided. A replay of the webcast will be available shortly after the call concludes. About IgA nephropathy (IgAN) IgAN is a chronic autoimmune kidney disease that affects approximately 169,000 people in the U.S. and is most often diagnosed in young adults. The disease is characterized by the deposition of pathogenic IgA-containing immune complexes in the kidneys. These deposits can lead to increased protein in the urine, also known as proteinuria, declining kidney function, and potentially end-stage kidney disease requiring dialysis or a transplant. IgAN often requires lifelong treatment to preserve kidney function and prevent progression to kidney failure. About JADE101 JADE101 is an anti-APRIL monoclonal antibody being developed for the treatment of IgAN. By targeting APRIL, a protein involved in the overproduction of IgA, JADE101 aims to reduce the levels of disease-driving IgA, decrease proteinuria, and preserve kidney function. Engineered with half-life extension technology, JADE101 is designed for dosing at intervals of at least eight weeks, offering the potential for durable clinical activity and improved patient convenience, particularly important for a condition often diagnosed in young adulthood and potentially requiring life-long treatment. About Jade Biosciences, Inc. Jade Biosciences is focused on developing best-in-class therapies to address critical unmet needs in autoimmune diseases. Its lead candidate, JADE101, targets the cytokine APRIL for the treatment of immunoglobulin A nephropathy, with initiation of a first-in-human clinical trial expected in the second half of 2025. Jade’s pipeline also includes a second development candidate, JADE201, and an undisclosed antibody discovery program, JADE-003, both currently in preclinical development. 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 . SOURCE: Jade Biosciences

Otsuka Pharmaceutical has shared positive results from a late-stage study of its investigational monoclonal antibody sibeprenlimab in adults with the rare kidney disease immunoglobulin A nephropathy (IgAN). The phase 3 VISIONARY study, which Otsuka said is the largest IgAN trial to date, has been comparing the candidate against placebo in approximately 510 patients who were receiving standard-of-care therapy. IgAN occurs when the IgA protein accumulates in the kidneys and damages them. This impedes their filtering function and, as a result, the kidneys start to let substances such as blood and protein leak into the urine. The disease typically appears in adults aged 20 to 40 years and can lead to end-stage kidney disease over the lifetime of most patients. Results presented at this year’s European Renal Association Congress showed that patients treated with sibeprenlimab, administered subcutaneously every four weeks, achieved a 51.2% reduction in excess protein in the urine (proteinuria) compared to placebo at nine months. The safety profile of sibeprenlimab was also found to be favourable and consistent with previously reported data, Otsuka said, with 76.3% of sibeprenlimab-treated patients experiencing any treatment emergent adverse event compared to 84.5% in the placebo group. John Kraus, executive vice president and chief medical officer, Otsuka Pharmaceutical Development & Commercialization, said: “Proteinuria control is an important independent predictor for long-term prognosis, and this interim data reinforces our belief that selectively targeting APRIL [a cytokine in the tumour necrosis factor family] has the potential to be an effective and safe approach for this progressive and irreversible kidney disease.” VISIONARY will continue to evaluate change in kidney function over two years, as measured by estimated glomerular filtration rate, and is expected to be completed early next year. Sibeprenlimab has already been granted Priority Review designation by the US Food and Drug Administration, with a target action date of 28 November 2025. “The safety data emerging from VISIONARY is reassuring and adds to our existing knowledge about sibeprenlimab’s safety profile from prior programmes,” said Dana Rizk, professor of medicine in the division of nephrology at the University of Alabama at Birmingham. “This is very exciting news for patients and adds a therapeutic option with a novel mechanism of action potentially targeting the immunologic pathogenesis of IgAN.”