Jade Biosciences (JBIO) Study update summary

Program Overview and Rationale

• JADE301 is a fully human, half-life-extended, high-affinity anti-interferon beta monoclonal antibody for dermatomyositis (DM), designed for infrequent subcutaneous dosing.

• DM is a rare, debilitating autoimmune disease with significant unmet need, affecting about 50,000 adults in the U.S.

• Interferon beta is a validated upstream driver of DM, with selective inhibition showing benefit in both skin and muscle disease.

• JADE301 aims to combine potent interferon beta neutralization with convenient subcutaneous dosing and durable disease control.

• JADE301 is part of a pipeline including JADE101 and JADE201, all licensed from Paragon Therapeutics.

Preclinical Data and Differentiation

• JADE301 demonstrated 2.5-fold higher binding affinity and up to 8-fold greater functional potency than dazukibart in vitro, with no off-target interferon binding.

• Potently inhibited downstream IFN-β signaling and suppressed MX-1 in human dermal fibroblasts and immune cells.

• In non-human primates, JADE301 showed a 25–30 day half-life, three times longer than dazukibart, and predicted human subcutaneous bioavailability of 73–75%.

• High subcutaneous bioavailability and favorable pharmacokinetics support infrequent dosing and reduced patient burden.

• Preclinical studies support potential for best-in-class efficacy and a differentiated dosing profile.

Safety and Tolerability

• Well tolerated in non-human primates at all subcutaneous doses up to 200 mg/kg, with no treatment-related adverse clinical or laboratory findings.

• No treatment-related histopathology findings observed in GLP toxicology studies.