Jade Biosciences (JBIO) investor relations material

JADE101 and IgA nephropathy

• JADE101 is a femtomolar-binding anti-APRIL antibody with an Fc YTE half-life extension; Phase I showed ~70% IgA reduction at 700 mg and supports Q12W dosing.

• Phase II began in May, with Q8W and Q12W dose arms; interim results, including UPCR, are expected in Q2 2027.

• Phase III is expected to start in Q4 2026; the design is 1 year randomized, placebo-controlled, followed by 48 weeks open-label, with 2:1 randomization and two dose levels.

• Q2 2027 Phase II assessment will consider UPCR, Gd-IgA1 reduction depth and durability, and ADAs; the goal is a robust dataset with at least ~6 months’ follow-up.

• JADE101 was designed to avoid ADA-related exposure loss; Phase I showed no ADA signal, while Phase II will further assess the fully human antibody and novel epitope.

IgA nephropathy market and clinical context

• Management estimates a $20B U.S. IgAN market, with ~100,000 patients eligible under KDIGO’s >0.5 g/day proteinuria threshold; launched therapies have WACs of $400K–$425K.

• Phase III readouts cited placebo-adjusted proteinuria reductions of 51% for sibeprenlimab, ~42% for atacicept, and 49.8% for povetacicept, with eGFR stabilization reported.

• Management argued clinical data have not shown added efficacy from BAFF inhibition; convenience and safety remain priorities for largely asymptomatic patients.

• Current patient starts remain in the low thousands; sibeprenlimab consensus peak sales for 2026 were cited as below $100M in December, versus a current trajectory toward ~$400M.

• B-cell modulators are expected to remain frontline options alongside ACE inhibitors and ARBs; monthly dosing may offer a convenience advantage, while management sees room for multiple therapies.

JADE201

• JADE201 is an afucosylated anti-BAFF-R antibody designed for enhanced ADCC, deep B-cell depletion, tissue activity, and blockade of compensatory BAFF signaling.

• Phase I in RA began in May, with data expected in 2027; assessment includes B-cell depletion level and durability, plus receptor occupancy.

• Indication evaluation includes ANCA-associated vasculitis, ITP, membranous nephropathy, and potential combinations with anti-APRIL in renal disease; partnering is under consideration.

• Sjögren’s is also being monitored; management expects sibeprenlimab study data around Q2 2027 and may consider a combination strategy based on the findings.