Jade Biosciences, Inc. Common Stock Stifel 2026 Virtual Immunology and Inflammation Forum

Everyone, we're back. Really happy to have the Jade Biosciences team here with us for the next fireside, Tom Frohlich, CEO, Andrew King, President of R&D, CSO, IgAN extraordinaire. Maybe I'll kick it over to Tom to give us a quick overview of the company, and then we'll get into the Q&A.

Thanks so much, Alex, and thanks for hosting us and all the support from Stifel in the conference and beyond. Jade, we're a company focused on developing best-in-class assets across a number of different autoimmune diseases. We have three assets that we've licensed from Paragon, which I'm sure many people are familiar with. They're super high-quality protein engineers focused on developing high-affinity binding antibodies with long half-life to develop best-in-class therapeutics. We have three assets. Our lead program is JADE101, which is anti-APRIL, focused on IgAN initially. We think it's a best-in-class profile with a possibility of having deepest levels of IgA reduction to maximize clinical activity available to the mechanism, and to be able to do that in a very convenient format with acute Q12-week maintenance dosing for patients.

That program's currently in a phase II trial with data expected in 2027, and we're moving exceptionally quickly to initiate a phase III trial, which we're anticipating dosing the first patient in the first half of 2027. We also have JADE201, which is an anti-BAFF-R antibody, really applicability across a number of different autoimmune disease, anything that's B-cell mediated. That program is currently in a phase I rheumatoid arthritis trial, moving towards data next year as well in 2027. Broad indication potential. We're following the footsteps of ianalumab, although JADE201 has a longer half-life, so we can capture better clinical activity with more convenient dosing for patients as well. JADE301, recently disclosed, very exciting program. It's an anti-interferon beta, going after dermatomyositis, an area of large unmet need.

We're currently tracking towards initiating that program, dosing the first healthy volunteer this year in a phase I study with data next year in 2027. That program is following in the footsteps of another anti-interferon beta in dermatomyositis called Dasukibart, which is at Pfizer. We're aiming to have subcutaneous dosing where Dasukibart is IV, and really capture the clinical activity that we've seen with interferon beta, which is really the best results in terms of total improvement score on neuromuscular aspects, but also on the skin. Super exciting program. All that's underpinned by a strong financial position and a really high-quality team that can move these programs forward.

Great overview. We have seen now two of the 2-year phase III data sets out of the first-gen APRIL, BAFF-APRILs from both Otsuka with sibeprenlimab and atacicept from Vera. Both of them, long story short, stabilize eGFR at 2 years. From that perspective, where is the unmet need in IgAN as we kind of look at those data sets?

Yeah. You introduced Andrew as IgAN extraordinaire, so Andrew, why don't you take that one?

Yeah. It has been really, truly remarkable to see the evolution of the anti-APRIL response in IgAN over the last 5 or so years. This eGFR stabilization we have now seen that you referenced from both sibeprenlimab and atacicept in phase III is truly transforming for the trajectory of these young IgAN patients that would typically face high lifetime risk of progressing to end-stage kidney disease requiring dialysis or transplantation. We do think that that really sets the bar and is likely the best you can achieve in IgAN is that eGFR stabilization, since decreased eGFR in chronic kidney disease and in IgAN specifically is generally thought to be a result of a loss of nephron number, which won't be restored by a therapy like this. So stabilization is the best you can hope for.

We hope to be able to replicate that with JADE101, that full disease-modifying benefit manifested through eGFR stabilization. But we do think there are important opportunities to differentiate in this patient population. Firstly, as I mentioned, these are young adults when they are diagnosed in their 20s and 30s, so they need lifelong therapy, potentially for decades. So we do think that convenience and reducing the patient burden is going to be really important in IgAN to give them more freedom from their autoimmune disease, and that fear of progressing to end-stage kidney disease. With JADE101, it has been designed for convenient infrequent sub-Q injections to reduce the patient burden, provide better convenience, and more freedom for these young, otherwise healthy IgAN patients.

We also think there's opportunity, according to the guidelines, to really deliver agents that not only stabilize eGFR, which is great long term, but is difficult to treat towards because you need long-term follow-up to really understand the trajectory of eGFR. The guidelines are really focusing on these strict proteinuria targets, driving patients back below 0.5 grams per day, preferably back to within the normal range of 0.3 grams per day, which gives you the greatest confidence that that long-term eGFR and the long-term outcomes will be favorable for these patients without having to track eGFR over time.

We do think there's some opportunity to differentiate on efficacy with JADE101 being a highly potent femtomolar inhibitor APRIL, and being administered with a loading dose or induction dose strategy with the goal to drive IgA down as quickly as possible and as deeply as possible to try and bring earlier benefits in terms of proteinuria reduction and higher rates of achieving those remission-like targets, which would be a great profile to combine with the convenient infrequent dosing schedule.

Yeah. With that context, I guess, can you talk through the phase I data and sort of where those data sort of fit into how you're thinking about that product profile?

Yeah, the phase I data is particularly informative in the setting of an anti-APRIL therapy in IgAN because it's so translationally rich with biomarkers that are ultimately predictive of clinical efficacy in IgAN. IgAN is a disease driven by IgA-containing immune complexes. The really rich responses you get with IgA reduction in healthy volunteers, which is highly consistent with the IgA reduction you ultimately see in IgAN patients with these agents and is predictive of clinical benefit. The early IgA reductions observed at 8 weeks with an anti-APRIL have a high association with the proteinuria reductions you ultimately see at week 36. We think that's a particularly important endpoint to anchor on in the phase I study.

And what we observed with JADE101, consistent with our goal of delivering these rapid and deep IgA reductions early to produce the best benefit on proteinuria, was at the 700 milligram induction dose, we saw a 70% reduction in IgA, which is numerically greater than has been observed with single doses of the first-generation agents, which were really bottoming out in the mid 50% reduction from baseline and required repeat dosing over time to get down to those larger reductions in IgA. We do think that particular endpoint from the phase I study is highly encouraging about the profile of JADE101, and in our view, highly de-risking.

Yeah that we won't be able to deliver the full disease-modifying benefit of IgA reduction.